JPH09273060A - Conjugate long fiber nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a core-sheath type conjugate long fiber nonwoven fabric composed of a sheath component of a high density polyethylene and a core component of a polypropylene and excellent in softness and feeling and to provide a method for producing the nonwoven fabric excellent in spinnability and opening abilities. SOLUTION: A sheath component is composed of a high density polyethylene having a Q-value (a weight average molecular weight/a number average molecular weight) of >3.5 and <=4.5, a melt flow rate of 10-70g/10min determined by a method with conformity to JIS K-7210 under conditions of 210 deg.C and a load of 2.16kg, and a density of 0.94-0.97g/cm<3> . A core component is composed of a polypropylene having a melt flow rate in the range of 10-100g/10min. The core component and the sheath component are combined so that the difference in the melt flow rates between the core component and the sheath component is in the range of 0-35g/10min. The core component and the sheath component are spun by melt extrusion spinning at an identical temperature selected from a range of melt spinning temperature of 220 deg.C to 270 deg.C, taking up a group of the spun continuous filaments at a high speed by an ejector, forming a web by collecting and laying fibers of 1-10 denier in fineness on a moving supporting body for collection followed by thermobonding.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to medical / hygiene materials,
It can be used in a wide range of fields such as general industrial materials, and due to its flexibility, it is particularly suitable for surface materials of sanitary materials such as disposable diapers and sanitary napkins. The present invention relates to a manufacturing method.

[0002]

2. Description of the Related Art A thermoplastic resin is melt-spun in a melt extruder, and the spun continuous filament (filament) is taken up by high-speed high-pressure air and placed on a moving net for support. Spunbond nonwoven fabric, which is obtained by collecting and depositing it into a web and then hot embossing, has higher productivity than other dry or wet nonwoven fabrics, and because it consists of continuous long fibers, it has mechanical properties such as tensile strength. Are better. In particular, among the spunbonded nonwoven fabrics, a spunbonded nonwoven fabric made of a polyolefin resin has a small specific gravity, as compared with a nonwoven fabric manufactured using a polyamide resin such as nylon or a polyester resin such as polyethylene terephthalate as a raw material, and a filament. Due to its excellent flexibility, disposable sheets,
Advances have been made in fields such as surface materials for sanitary materials such as diapers and sanitary napkins.

However, in a spunbonded non-woven fabric composed of a thermoplastic resin as a single component, when heat-bonding is performed by heat embossing, the bonding point is formed into a film without maintaining the fiber shape, and the texture is significantly impaired. Since this is not preferable, in order to improve this point, it has been proposed to use a composite fiber composed of different resins. Conventionally, a part or all of the fiber surface is covered with another thermoplastic resin having a softening point lower than that of the thermoplastic resin forming the fiber, that is, a core-sheath fiber is formed, and a difference in softening point is formed. Nonwoven fabrics that improve the adhesiveness and the texture after bonding are known (Japanese Patent Publication No. 42-21318 and Japanese Patent Publication No. 43-1776). Also, Japanese Examined Japanese Patent Publication Sho 54-38
In JP-A-214, a crystalline polymer having a fiber-forming ability such as polypropylene is used as a core component, and polystyrene, polyethylene, ethylene-propylene copolymer having a softening point lower than that of the polymer by at least 40 ° C. is used as a sheath component. In such a case, in the conventional method of producing a composite fiber by two steps of spinning and drawing, since the affinity at the core-sheath interface is weak, drawability is poor, and in order to eliminate the disadvantage that each component peels depending on the drawing conditions, When performing composite spinning, the spinning yarn is 3 per minute,
A manufacturing method is disclosed in which it is taken at a speed of 200 to 9,800 m, and is deformed, cooled, and solidified all at once.

As described above, the composite long-fiber non-woven fabric made of polyolefin resin is most commonly composed of polypropylene resin as the core component and polyethylene resin as the sheath component. Among them, linear low-density polyethylene is expected to have a soft texture, but it has poor spinnability and cannot provide a uniform nonwoven fabric. There is a problem that you cannot do it.
In order to improve this problem, JP-A-2-61156 discloses a copolymer of ethylene and octene-1, which contains substantially 1 to 10% by weight of octene-1 and has a density of 0.900 to 0. A linear low density polyethylene of 940 g / cm ^{3 was used} as the sheath component of the composite fiber, the core component of the composite fiber was polypropylene with a melt flow rate value of 5 to 45 g / 10 min, and the weight ratio of the polyethylene to the polypropylene was A non-woven fabric composed of a composite long fiber of 20:80 to 80:20 is disclosed. However, even with this method, the spinnability is improved to some extent, but there is a drawback in that the openability is still poor.

Further, in order to solve the problem of openability,
In JP-A-5-186951, high density polyethylene as a sheath component of composite fibers is blended with 2 to 25% by weight of polypropylene per high density polyethylene, and Q value (weight average molecular weight / number average molecular weight) is 3.5 or less. As a core component, the melt flow rate is 5 to 70 g.
Disclosed is a non-woven fabric made of a composite fiber which uses polypropylene for / 10 minutes and has a heat-bonding property with good texture even in a low basis weight. In this case, the blended polypropylene prevents the peeling phenomenon of the core-sheath component and plays a role of improving the spinnability, but the process for blending is additionally increased, which is disadvantageous in manufacturing cost and at the same time, The presence of the polypropylene component causes the thermal characteristics to approach those of the core polypropylene, so that the physical properties of the spunbonded nonwoven fabric are inferior when heat-bonded.

[0006]

In view of the above situation, the present inventors have earnestly studied a combination of a high density polyethylene as a sheath component of a core-sheath type composite nonwoven fabric and polypropylene as a core component, and as a result, as a sheath component, Focusing on the difference in the molecular weight distribution of the high-density polyethylene used and the melt flow rate of the two thermoplastic resins, the weight average molecular weight was divided by the number average molecular weight even if the density of the resin was in a specific high range. Is defined as a value, and a high-density polyethylene having a Q value indicating a molecular weight distribution width in a specific range is used as a sheath component, and polypropylene having a difference in melt flow rate from the resin in a specific range is combined as a core component,
Moreover, when the same melting temperature is used during melt spinning, the charge amount is large, the defibration property is excellent, the viscosity does not become large when the spun filament group is extended, and the spinnability and spinnability are improved. It is extremely excellent and dusty with its excellent heat adhesion.
They have found that a core-sheath type composite long-fiber nonwoven fabric excellent in flexibility and texture can be obtained, and have completed the present invention. An object of the present invention is to use a high-density polyethylene resin as a sheath component and a polypropylene resin as a core component, and a core-sheath type composite long-fiber nonwoven fabric excellent in flexibility and texture and having good spinnability and openability and having the above-mentioned characteristics. It is to provide a method for producing the non-woven fabric.

[0007]

The first aspect of the present invention is to define a non-woven fabric formed from a composite long fiber composed of a core component and a sheath component, wherein the sheath component is defined as a value obtained by dividing the weight average molecular weight by the number average molecular weight. According to JIS K 721, the high density polyethylene and the core component having a Q value of more than 3.5 and 4.5 or less and a density of 0.940 to 0.970 g / cm ³ are used.
210 ° C, load 2.16 measured by the method described in 0.
The melt flow rate under the condition of kg is 10 to 10
A composite long-fiber nonwoven fabric comprising polypropylene in the range of 0 g / 10 minutes and having a fineness of the composite long fibers in the range of 1 to 10 denier. A second aspect of the present invention is the composite continuous fiber nonwoven fabric according to the first aspect of the present invention, wherein the weight ratio of the sheath component in the fiber cross-sectional area orthogonal to the fiber axis is in the range of 20 to 80%. A third aspect of the present invention is a method for producing a nonwoven fabric formed of a composite long fiber consisting of a core component and a sheath component, which comprises melt extrusion of different thermoplastic resins, and the sheath component has a weight average molecular weight of a number average. Q value defined by the value divided by the molecular weight is 3.5
In the range of more than 4.5 and not more than 4.5, the melt flow rate under the conditions of 210 ° C. and a load of 2.16 kg measured by the method described in JIS K 7210 is 10 to 70 g / 10.
Within the range of minutes, and the density is 0.940 to 0.970 g / c
The high-density polyethylene and the core component of the composite long-fiber in the range of m ³ have a flow rate measured by the above method of 10 to 10
Polypropylene in the range of 0 g / 10 minutes is combined with the difference in the melt flow rates being in the range of 0 to 35 g / 10 minutes and melted at the same temperature selected from the range of melt spinning temperature 220 ° C to 270 ° C. Extrusion spun, spun continuous filaments at high speed with an ejector to bring the composite filaments to a fineness range of 1 to 10 denier, then depositing the fibers on a moving collector to form a web. And then heat-bonding the composite long-fiber nonwoven fabric.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic high-density polyethylene resin used as the sheath component of the composite long fiber in the present invention is defined as the weight average molecular weight divided by the number average molecular weight (weight average molecular weight / number average molecular weight). The Q value to be used should be more than 3.5 and 4.5 or less, preferably 3.7 to 4.3. This Q value means gel
Permeation chromatography (gel permeati
It is indicated by the ratio of the weight average molecular weight and the number average molecular weight of the polymer obtained by on chromatography), and this value indicates the distribution width of the molecular weight of the resin, and when the thermoplastic resin is melt-spun by a melt extruder. It is known that this has a great influence on the manufacturability and processability of the filament. That is, it means that the width of the molecular weight distribution becomes wider as the Q value becomes larger, and when the resin is melt-spun in a melt extruder and the spun filament is elongated, the viscosity of the resin becomes large and the spinnability is increased. Is reduced. If the Q value of the high-density polyethylene exceeds 4.5, yarn breakage frequently occurs during melt spinning, and it becomes difficult to produce a composite continuous fiber having a fineness of 10 denier or less, which is not suitable. When the Q value is 3.5 or less, it is difficult to control the synthesis conditions for producing the polymer, and thus it is not easy to obtain the resin.

The density of the high density polyethylene is 0.
940 to 0970 g / cm ³ , preferably 0.945 to
It is in the range of 0.965 g / cm ³ . Density is 0.940
When a polyethylene polymer of less than g / cm ³ is used, when the core-sheath type composite continuous fiber using this resin is charged and the fibers are opened, the charge amount is reduced and the openability is reduced. The texture of the composite long-fiber non-woven fabric is deteriorated and the density becomes 0.
High density polyethylene exceeding 970 g / cm ³ is difficult to obtain on the market. As the high-density polyethylene, the melt flow rate (hereinafter referred to as MFR) measured by the method described in JIS K 6760 is 10 to 70.
g / 10 minutes, preferably 10 to 50 g / 10 minutes. High-density polyethylene with an MFR of less than 10 g / 10 min cannot easily be subjected to high-speed melt spinning unless the melting temperature is extremely high during spinning, and the spinneret surface becomes soiled during spinning at extremely high temperatures. Easy and not preferable for operation. On the other hand, when the MFR exceeds 70 g / 10 minutes, yarn breakage is likely to occur, and not only the texture of the obtained composite long-fiber nonwoven fabric is deteriorated but also the strength is lowered, which is not preferable. The high-density polyethylene may contain additives such as a lubricant, a pigment, a stabilizer, a flame retardant and an antibacterial agent.

The polypropylene used as the core component in the present invention has a Q value in the range of 2.0 to 3.5 and J
210 measured by the method described in IS K 7210
MFR of 10 to 10 under conditions of ℃ and load of 2.16 kg
It is in the range of 0/10 minutes, preferably 30 to 80 g / 10 minutes. A polypropylene having a Q value of less than 2.0 is difficult to obtain because it is difficult to manufacture, and a polypropylene having a Q value of more than 3.5 causes yarn breakage. Polypropylene having an MFR of less than 10 g / 10 min is not preferable for operation because high-speed melt spinning cannot be easily performed unless the melting temperature is raised and the spinneret is liable to be contaminated at spinning at a high temperature. On the other hand, if the MFR exceeds 100 g / 10 minutes, yarn breakage is likely to occur, and not only the texture of the obtained composite long-fiber nonwoven fabric is deteriorated but also the strength is lowered, which is not preferable. Further, the polypropylene may contain additives such as a lubricant, a pigment, a stabilizer and an antibacterial agent as in the case of the high density polyethylene.

In the present invention, the weight ratio of the high-density polyethylene as the sheath component in the fiber cross-sectional area of the composite long fibers constituting the nonwoven fabric is 20 to 80% by weight. If the weight ratio of the high-density polyethylene is less than 20% by weight, the fiber strength will be high, but the adhesive strength will be weak, and the strength of the resulting nonwoven fabric will be too weak, which is not preferable in practice. On the contrary, the weight ratio of high density polyethylene is 80
If the content is more than 10% by weight, the adhesive strength will be high, but the fiber strength will be too weak, and the strength of the resulting nonwoven fabric will be too weak, which is not preferable. The fineness of the composite long fibers used in the present invention is in the range of 1 to 10 denier. Fineness of long fiber is 1
If it exceeds 0 denier, the fiber diameter becomes too thick, the resulting nonwoven fabric becomes hard and the texture is deteriorated, and if the fineness is less than 1 denier, it is difficult to manufacture. The cross-sectional shape of the composite long fiber may be a modified shape or a flat shape in addition to the circular cross section.

The basis weight of the composite long-fiber nonwoven fabric according to the present invention is 5 to 150 g / cm ² . Unit weight is 150g / c
When it exceeds m ² , the nonwoven fabric becomes too hard and the texture becomes poor, and when the basis weight is less than 5 g / cm ² , the strength of the nonwoven fabric becomes too low and it becomes difficult to stably manufacture the nonwoven fabric.
The present invention relates to a nonwoven fabric formed from composite long fibers composed of a core component and a sheath component by melt extrusion of different thermoplastic resins and a method for producing the same, wherein the sheath component has a Q value of 3.
MFR of 10 to 70 g / in the range of more than 5 and 4.5 or less
In 10 minutes, the density is 0.940-0.970 g / cm
High density polyethylene and core components in ³ ranges have Q value of 2.
In the range of 0 to 3.5, polypropylene having an MFR of 10 to 100 g / 10 min is combined, and the difference between the MFRs is combined in the range of 0 to 35 g / 10 min, and the melt spinning temperature is 220 ° C. to 270 ° C. Melt-extrusion spinning at the same temperature selected from the range of 1., the spun continuous filament group is taken up by air sucker at high speed to make the fineness of the composite long fiber in the range of 1 to 10 denier, and then the fiber A web is formed by collecting and depositing on a moving support for collection, and then heat-bonding.

The composite continuous fiber of the present invention can be obtained by using a known melt extrusion spinning apparatus for composite continuous fiber. The polypropylene of the core component and the high-density polyethylene of the sheath component are required to be melt-spun with respective resins at the same temperature selected from the range of 220 to 270 ° C. for melt spinning. If the spinning temperature is outside the above range, the spinning condition will be poor and it will be difficult to obtain a satisfactory nonwoven fabric. That is,
If the spinning temperature is lower than 220 ° C., the spinning speed must be increased, which requires high air pressure.
It is difficult to obtain fibers having a fineness of 1 to 10 denier without causing yarn breakage. On the other hand, when the spinning temperature exceeds 270 ° C, the strength of the spun filament is weakened, and not only the yarn breakage is likely to occur, but also the nozzle surface is easily soiled, and the nozzle surface is soiled when operating for a long time. This is not preferable because the yarn breakage due to the yarn increases. The same temperature selected from the above range during melt spinning means, in the present invention, that the respective resins of the core component and the sheath component are spun at substantially the same melt spinning temperature. Within ± 1.5 ° C, preferably ± 1.0 ° C
Is allowed up to. If the absolute value of the difference between the melt spinning temperatures of the two types of resin exceeds 3 ° C and becomes large, the adhesiveness is impaired at the contact surface between the core component and the sheath component, which eventually causes yarn breakage, resulting in non-uniform nonwoven fabric. Become.

In the present invention, MFR of high density polyethylene as the sheath component and MFR of polypropylene as the core component are further used.
And the difference between and is in the range of 0-35g / 10 minutes,
By melt-spinning at the same temperature selected from the melt-spinning temperature range, the composite long-fiber filament after melt-extrusion becomes smooth, and no deviation occurs at the joint portion of the core-sheath due to uneven cooling, Since there is no distortion due to the difference in melt elongation characteristics, good spinnability can be realized. The high-density polyethylene as the sheath component and the polypropylene as the core component were extruded from the respective spinnerets of the melt-extrusion spinning machine at the same temperature and spun, and then drawn by high-speed air by an ejector, stretched, and then formed. A large number of long fibers are applied to a collision plate to be triboelectrically charged, and the fibers are opened by the repulsive force of the electric charges. In this case, corona discharge treatment can be performed as the charging method. Next, the large number of filament filament groups that have been uniformly spread are collected and accumulated on a collecting support to form a web. In this way, even with fine denier composite filaments, a web can be formed very easily, and composite filaments composed of polypropylene and high-density polyethylene, which have an extremely excellent texture, can be obtained from high-speed spinning with a reduced yarn breakage rate. Will be available.

In the present invention, a large number of long fibers accumulated on a support is formed into a web, and the web is heat-bonded by providing self-bonding areas of the fibers at regular intervals. . This self-fusing area is formed by introducing the web between a heated uneven roll and a smooth roll, and applying heat and pressure treatment, whereby the sheet portion corresponding to the convex portion of the uneven roll is fused. To be done. In this case, the temperature of the roll is 5 than the melting point of HDPE of the sheath component.
-30 ° C, preferably 10-25 ° C lower temperature. If the difference between the roll temperature and the melting point of the resin is less than 5 ° C., the fibers adhere to the roll during thermocompression bonding with the roll, which causes manufacturing troubles, which is not preferable. On the other hand, if the difference between the roll temperature and the melting point of the resin exceeds 30 ° C., the self-fusing part is not sufficiently formed, the strength of the sheet is remarkably lowered, and fuzz becomes severe, which is not suitable. The pressure when performing thermocompression bonding with an uneven roll and a smooth roll is
10-80 kg / cm, preferably 20-60 kg / c
m. If the pressure is less than 10 kg / cm, the formation of the self-bonding area by the thermocompression bonding process may be insufficient,
If it exceeds 80 kg / cm, the self-fusing area becomes a film and the texture of the nonwoven fabric may be impaired. As a method of forming the self-fusing region, a web composed of a continuous continuous fiber filament group is introduced between an uneven roll and an ultrasonic horn, and subjected to ultrasonic treatment,
It is also possible to form a spot fusion-bonded portion corresponding to the convex portion.

In the present invention, the area of each self-bonding zone is in the range of 0.03-4 mm ² . If the area of the self-bonding area is less than 0.03 mm ² , the strength of the nonwoven fabric is insufficient, which is not preferable. Conversely, the self-fusing area is 4 mm
^When it exceeds ² , the nonwoven fabric becomes too hard. The total area of the self-bonding area is 2 to 3 of the total surface area of the composite long-fiber nonwoven fabric.
It is 0 area%. Total area of self-bonding area is 2% by area
If it is less than 1, the strength of the nonwoven fabric is insufficient and the self-bonding area is 30.
If the area% is exceeded, the nonwoven fabric becomes hard. The composite long-fiber non-woven fabric composed of high-density polyethylene as a sheath component and polypropylene as a core component obtained as described above has excellent flexibility and texture, and is variously processed as necessary, a sanitary material, Medical substrate, clothing substrate, household substrate,
Used as an industrial base material.

[0017]

EXAMPLES The present invention will be described more specifically with reference to examples below, but the present invention is of course not limited to these. In the following Examples and Comparative Examples,% means% by weight unless otherwise specified.

Example 1 MFR 20 g / 10 minutes, density 0.960 g / cm ³ , Q
High-density polyethylene resin (manufactured by Mitsubishi Chemical Corporation) having a value of 4.0 and a melting point of 131.5 ° C is used as a sheath component, and MFR 40g / 10
Min, polypropylene resin with Q value of 3.0 (manufactured by Mitsubishi Chemical Corporation)
Was prepared as a core component. Next, using a core-sheath composite spinning spinneret in a melt extruder, the weight ratio of the sheath component to the fiber cross-sectional area orthogonal to the fiber axis of the composite long fibers constituting the non-woven fabric was set to 30%, and each of the above resins was used. 250 ± 1
After heating to ℃ to melt and extruding from a large number of fine holes,
A long fiber filament group was formed by drawing with a high-speed air by an ejector, and collected and deposited on a moving wire-made collection support to obtain a web. Then this web 1
It is introduced between an uneven roll and a smooth roll heated to 20 ° C., and a portion corresponding to the convex portion of the uneven roll is fused at a linear pressure of 40 kg / cm to obtain a composite continuous fiber nonwoven fabric having a basis weight of 40 g / m ^2. It was The area of each self-fusion area is 0.1
2mm ² , total area of self-bonding area is 4% by area
The fineness of the composite filament was 3 denier. The obtained long-fiber nonwoven fabric was tested by the following test method to evaluate its quality.

Test method (1) Spinnability: The spinnability of the resin was evaluated by the number of yarn breakages during melt spinning. The evaluation was carried out in the following five stages. 5 ... No yarn breakage and extremely good spinnability. 4 ... Almost no yarn breakage and good spinnability. 3 ... There is some yarn breakage, but there is no problem and spinnability is normal. 2 ... There are many yarn breaks, and the spinnability is poor. 1 ... Many yarn breakages and extremely poor spinnability. (2) Sheet formation: The formation of the obtained long-fiber nonwoven fabric was evaluated by sensory evaluation. The evaluation was carried out in the following five stages. 5 ... The formation is extremely good. 4 ... The formation is good. 3 ... The formation is normal. 2 ... The formation is bad. 1 ... The formation is extremely bad.

(3) Flexibility: The flexibility of the obtained long-fiber nonwoven fabric was evaluated by sensory evaluation. The evaluation was carried out in the following five stages. 5: The flexibility is extremely good. 4 ... Good flexibility. 3 ... Flexibility is normal. 2 ... Inferior in flexibility. 1 ... The flexibility is extremely poor. (4) Tensile strength: The tensile strength was measured by the method specified in JIS P8113.

Example 2 MFR 25 g / 10 minutes, density 0.955 g / cm ³ , Q
A high density polyethylene having a value of 3.5 and a melting point of 134 ° C. (manufactured by Mitsubishi Chemical Co., Ltd.) was used as a sheath component, and a polypropylene resin having an MFR of 50 g / 10 minutes and a Q value of 2.7 (manufactured by Mitsubishi Chemical Co., Ltd.) was prepared as a core component. Next, using a core-sheath composite spinning spinneret in a melt extruder, the weight ratio of the sheath component to the fiber cross-sectional area orthogonal to the fiber axis of the composite long fibers constituting the non-woven fabric was set to 30%, and each of the above resins was used. It is heated to 240 ± 0.5 ℃, melted, extruded from a large number of fine holes, and then stretched by high-speed air with an ejector to form filament filament groups, which are collected on a moving wire-made collection support.・ The web was deposited. This web is then 115
It was introduced between a concavo-convex roll heated to ℃ and a smooth roll, and a portion corresponding to the convex part of the concavo-convex roll was fused at a linear pressure of 20 kg / cm to obtain a composite long-fiber nonwoven fabric having a basis weight of 14 g / m ² . . The area of each self-bonding area is 1.0 mm ²
The total area of the self-fusing area was 15% by area, and the fineness of the composite continuous fiber was 2.8 denier.

Example 3 The resin was melt-spun in the same manner as in Example 1 except that the resin was heated to 260 ± 1 ° C., melted, and extruded through a large number of fine holes, and then stretched with a high-speed air by an ejector. To form a long fiber filament group, which was collected and deposited on a moving wire collecting support to form a web. Then, this web is introduced between a concavo-convex roll heated to 110 ° C. and a smooth roll, and a portion corresponding to the convex part of the concavo-convex roll is fused at a linear pressure of 60 kg / cm to give a basis weight of 50.
A composite long-fiber non-woven fabric of g / m ² was obtained. The area of each self-bonding area was 2.0 mm ² , the total area of the self-bonding area was 10% by area, and the fineness of the composite continuous fiber was 7.5 denier. The obtained composite long-fiber nonwoven fabric was tested by the above-mentioned test method to evaluate its quality.

Example 4 The resin was melt-spun in the same manner as in Example 2 except that the resin was heated to 230 ± 0.5 ° C. to be melted and extruded through a large number of fine holes, and then the resin was ejected with a high-speed air by an ejector. A long fiber filament group was formed by stretching and collected and deposited on a moving wire-made collection support to obtain a web.
Next, this web was introduced between a concavo-convex roll heated to 117 ° C. and a smooth roll, and a portion corresponding to the convex part of the concavo-convex roll was fused at a linear pressure of 30 kg / cm to obtain a composite having a basis weight of 24 g / m ² . A long-fiber nonwoven fabric was obtained. The area of the individual self-bonding areas was 0.28 mm ² , the total area of the self-bonding areas was 8 area%, and the fineness of the composite filament was 2.5 denier. The obtained composite long-fiber nonwoven fabric was tested by the above-mentioned test method to evaluate its quality.

Example 5 Other than using a spinneret for core-sheath composite spinning in a melt extruder and setting the weight ratio of the sheath component to the fiber cross-sectional area orthogonal to the fiber axis of the composite long fibers constituting the nonwoven fabric to 70%. A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1. The obtained composite continuous fiber was tested by the above-mentioned test method to evaluate its quality.

Comparative Example 1 A composite continuous fiber non-woven fabric was obtained in the same manner as in Example 1 except that a high density polyethylene resin for sheath component having a Q value of 5.0 (manufactured by Mitsubishi Chemical Corporation) was used. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 2 A composite continuous fiber non-woven fabric was obtained in the same manner as in Example 1 except that a polypropylene resin for core component (manufactured by Mitsubishi Chemical Corporation) having an MFR of 5 g / 10 min was used. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 3 As a sheath resin, MFR 35 g / 10 min, density 0.93
A long-fiber non-woven sheet was obtained in the same manner as in Example 1 except that linear low-density polyethylene having 7 g / cm ³ , a Q value of 3.0 and a melting point of 127.2 ° C. was used. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 4 A composite continuous fiber non-woven fabric was obtained in the same manner as in Example 1 except that the resin was heated to 280 ± 1.5 ° C., melted, extruded from a large number of fine holes and spun. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 5 A composite continuous fiber non-woven fabric was obtained in the same manner as in Example 1 except that each resin was heated to 210 ± 0.5 ° C. to be melted, extruded from a large number of fine holes and spun. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 6 When a resin was melted by heating, extruded through a large number of fine holes and spun, the melting temperature was 240 ° C. for the sheath component and 250 ° C. for the core component.
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the above was adopted. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 7 Except that the weight ratio of the sheath component in the cross-sectional area of the fibers orthogonal to the fiber axis of the composite long fibers constituting the nonwoven fabric was 90%.
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 2. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 8 Except that the weight ratio of the sheath component in the cross-sectional area of the fibers orthogonal to the fiber axis of the composite long fibers constituting the nonwoven fabric was set to 10%.
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 2. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

Comparative Example 9 A composite continuous fiber nonwoven fabric was obtained in the same manner as in Example 1 except that the fineness of the composite continuous fiber was 12 denier. The obtained long-fiber nonwoven fabric was tested by the above test method to evaluate its quality.

The results obtained in Examples 1-5 and Comparative Examples 1-9 are shown in Table 1.

[0035]

[Table 1]

As is clear from Table 1, according to the method of the present invention, when the resin is melt-spun, there is no yarn breakage, the spinnability is very excellent, and the texture is good. It is extremely excellent in texture and flexibility without damaging (Examples 1 to 5). On the other hand, when the Q value of the high-density polyethylene used as the sheath component exceeds 4.5, the yarn breaks frequently and the spinnability is poor (Comparative Example 1). A composite long-fiber nonwoven fabric having poor fineness and good texture cannot be obtained (Comparative Example 3). If the MFR of the polypropylene used as the core component is too low, yarn breakage frequently occurs during melt spinning, the spinnability is poor, and the texture is impaired (Comparative Example 2).

On the other hand, if the melting temperature is too high (280 ° C.) during melt spinning, the yarn is broken and the spinnability deteriorates, and the flexibility is normal, but the defibration property is poor and the formation is poor. (Comparative Example 4), if the melt spinning temperature is too low (210
C.), many yarn breakages, poor spinnability, and normal texture, but poor flexibility (Comparative Example 5). If a difference of 10 ° C is provided between the melting temperatures of the core component resin and the sheath component resin (core: 250 ° C,
(Sheath: 240 ° C.), many yarn breakages deteriorate spinability, and the texture is normal, but the flexibility deteriorates (Comparative Example 6). When the weight ratio of the sheath component occupying the fiber cross-sectional area orthogonal to the fiber axis of the composite long fiber constituting the nonwoven fabric is high (90%, Comparative Example 7) and when the weight ratio is low (10%, Comparative Example 8), The strength of the obtained composite long-fiber nonwoven fabric becomes weak. Furthermore, when the fineness of the composite long fibers becomes large (fineness: 12, Comparative Example 9), the spinnability is good, and the strength and texture of the obtained composite long fiber nonwoven fabric are normal, but the flexibility becomes extremely poor.

[0038]

INDUSTRIAL APPLICABILITY As described above, the present invention provides a core-sheath type composite filament made of polyolefin which is extremely excellent in flexibility and formation and can be used in a wide range of fields such as medical / sanitary materials and general industrial materials. An effect of providing a non-woven fabric and a manufacturing method thereof is obtained.

Claims (3)

[Claims] 1. A non-woven fabric formed from a composite long fiber comprising a core component and a sheath component, wherein the sheath component has a Q value defined as a value obtained by dividing a weight average molecular weight by a number average molecular weight of more than 3.5. In the range of 0.5 or less, the density is 0.940 to 0.97
The high-density polyethylene and the core component in the range of 0 g / cm ^{3 have} a melt flow rate of 210 to 100 g / 10 min in the condition of 210 ° C. and a load of 2.16 kg measured by the method described in JIS K 7210. A composite continuous fiber non-woven fabric made of polypropylene and having a fineness of the composite continuous fiber in the range of 1 to 10 denier. 2. The composite continuous fiber non-woven fabric according to claim 1, wherein the weight ratio of the sheath component in the fiber cross-sectional area orthogonal to the fiber axis is in the range of 20 to 80%. 3. A method for producing a non-woven fabric formed of composite long fibers composed of a core component and a sheath component, which comprises melt-extruding and spinning different thermoplastic resins, wherein the sheath component has a weight average molecular weight in a number average molecular weight. When the Q value defined by the divided value exceeds 3.5 and is 4.5 or less, JIS K 72
210 ° C., load 2.1 measured by the method described in 10.
Melt flow rate of 10 to 70 under the condition of 6 kg
In the range of g / 10 minutes, and the density is 0.940 to 0.97.
The high-density polyethylene in the range of 0 g / cm ³ and the core component of the composite filament have a flow rate of 1 measured by the above method.
Polypropylene in the range of 0 to 100 g / 10 minutes is combined within the range of 0 to 35 g / 10 minutes in the difference between the melt flow rates, and the same temperature is selected from the range of melt spinning temperature of 220 ° C. to 270 ° C. Melt-extruded and spun, and the spun continuous filaments are collected by an ejector at high speed to make the fine filaments have a fineness in the range of 1 to 10 denier, and then the fibers are deposited on a moving collector to form a web. A method for producing a composite long-fiber non-woven fabric, which comprises: