JPH10158969A - Conjugate filament nonwoven fabric and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sheath-core type conjugate filament nonwoven fabric extremely excellent in flexibility and touch, and to provide a method for producing the nonwoven fabric from the filaments good in spinnability and openability. SOLUTION: This method for producing the conjugate filament nonwoven fabric comprises melt-spinning a core component comprising polypropylene having a melt flow rate of 10-100g/10min and a sheath component comprising 20-80wt.% of high density polyethylene having a Q value of <=4.5, a melt flow rate of 10-70g/10min and a density of 0.945-0.970g/cm<3> and 80-20wt.% of linear low density polyethylene having a melt flow rate of 10-70g/10min and a density of 0.850-0.940g/cm<3> at a melt-spinning temperature of 220-270 deg.C, simultaneously taking off the spun fibers with a high speed ejector to draw and open the filaments, collecting and accumulating the obtained conjugate filaments having a fineness of 1-10 denier on a moving support to form a web, and subsequently subjection the web to an embossing treatment to thermally adhere the filaments. The difference between the melt flow rates of both the polyethylene is 0-35g/10min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to medical and hygiene materials,
It can be used in a wide range of fields such as general industrial materials, and especially its flexibility makes it possible to use a core-sheath type composite long-fiber nonwoven fabric made of a polyolefin resin suitable for surface materials of sanitary materials such as disposable diapers and sanitary napkins. It relates to a manufacturing method.

[0002]

2. Description of the Related Art A thermoplastic resin is melt-spun in a melt extruder, and a spun continuous filament (filament) group is drawn while being stretched by high-speed air, charged, opened, and then moved. It is obtained by collecting and depositing on a support consisting of a collecting net to form a web, melting and bonding the long fibers to each other with a hot embossing device consisting of a heating roll, and imparting form stability. Spunbond nonwoven fabrics have higher productivity than other dry nonwoven fabrics and wet nonwoven fabrics, and are excellent in mechanical properties such as tensile strength because they are composed of continuous filaments. In particular, among the spunbonded nonwoven fabrics, spunbonded nonwoven fabrics made of a polyolefin resin have a small specific gravity, compared to nonwoven fabrics manufactured using a polyamide resin such as nylon or an aromatic polyester resin such as polyethylene terephthalate as a raw material. In addition, due to the excellent flexibility of the filament itself, it has been attempted to advance into fields such as surface materials of sanitary materials such as disposable sheets, diapers, and sanitary napkins.

[0003] However, in a spunbonded non-woven fabric made of a thermoplastic resin consisting of a single component, when hot-melt bonding is performed by heating, the bonding point is formed into a film without maintaining the fiber shape, and the texture is significantly impaired. In order to improve this point, a nonwoven fabric using conjugate fibers composed of resins having different melting points as constituent fibers has been proposed. Conventionally, part or all of the fiber surface is covered with another thermoplastic resin having a lower softening point than the thermoplastic resin constituting the fiber, that is, a core-sheath fiber is formed, and the difference in softening point is reduced. Nonwoven fabrics are known which have improved adhesiveness by hot melting and improved texture after bonding (JP-B-42-21318 and JP-B-43-1776).

[0004] Japanese Patent Publication No. 54-38214 discloses that
A crystalline polymer having a fiber-forming ability such as polypropylene as a core component, and having a softening point at least 40 ° C. lower than that of the polymer, polystyrene, polyethylene, ethylene-
In the case where a poropylene copolymer or the like is used as the sheath component, in the conventional method of producing a conjugate fiber by two steps of spinning and drawing, the drawability is poor because the affinity at the interface between the core and the sheath is weak. However, in order to solve this drawback, in the case of composite spinning, the spun yarn is taken at a speed of 3,200 to 9,800 m / min, and is deformed, cooled, and solidified at once. Is disclosed. As described above, as a composite long-fiber nonwoven fabric made of a polyolefin resin, the configuration in which the core component is a polypropylene resin and the sheath component is a polyethylene resin is the most common.

[0005] Among these, linear low-density polyethylene is expected to have a soft hand, but has poor spinnability, does not provide a uniform nonwoven fabric, and has poor openability when forming a web. There is a problem that a nonwoven fabric having a low basis weight cannot be formed because of poor quality. In order to improve this problem, Japanese Patent Application Laid-Open No. 2-61156 discloses a copolymer of ethylene and octene-1 in which octene-1 is substantially one.
-10% by weight, density 0.900-0.940g
/ Cm ³ as a sheath component of the composite fiber, and the core component of the composite fiber has a melt flow rate of 5 / cm ^3.
45 g / 10 min. Polypropylene, wherein the weight ratio of the low density polyethylene to the polypropylene is 20:80 to
A nonwoven fabric composed of 80:20 composite filaments is disclosed. However, even with this method, although the spinnability is improved to some extent, there is a drawback that the spreadability is still poor.

[0006] In order to solve the problem of the spreadability, Japanese Patent Application Laid-Open No. Hei 5-186951 discloses that high density polyethylene is blended with 2 to 25% by weight of polypropylene per high density polyethylene as a sheath component of a composite fiber. A structure having a Q value (weight average molecular weight / number average molecular weight) of 3.5 or less was used, and the melt flow rate was 5 to 70 as a core component.
A nonwoven fabric made of a conjugate fiber using g / 10 minutes of polypropylene and having good thermal adhesion with good formation even at a low basis weight is disclosed. In this case, the polypropylene blended with the sheath component prevents the core-sheath component from peeling off and plays a role in improving spinnability. However, the presence of the polypropylene component in the sheath provides a soft touch unique to polyethylene. At the same time, the thermal properties approach those of polypropylene as the core component, so that when a spunbond nonwoven fabric is obtained by thermal bonding, a new problem arises in that the physical properties are poor.

[0007]

In view of this situation, the present inventors have considered the above-mentioned combination of high-density polyethylene and linear low-density polyethylene as the sheath component of the core-sheath type composite nonwoven fabric and polypropylene as the core component. As a result of intensive research to solve the problem, focusing on the difference between the molecular weight distribution of high-density polyethylene used as a sheath component and the melt flow rate of the three types of thermoplastic resins, the density of the resin is within a specific high range. Even if there is, defined by the value obtained by dividing the weight average molecular weight by the number average molecular weight, the Q value indicating the distribution width of the molecular weight is a high-density polyethylene having a specific range, and a linear low-density polyethylene having a lower melting point than the high-density polyethylene. Is used as a sheath component, and polypropylene having a difference in the melt flow rate of the resin within a specific range is further combined as a core component. In addition, when the same melting temperature is used during melt spinning, the charge amount increases, thereby significantly improving the spreadability, and furthermore, the spinnability and spinnability are extremely excellent, and furthermore, its excellent heat adhesion and Together, they found that a core-sheath type composite long-fiber nonwoven fabric excellent in flexibility and feeling could be obtained,
The present invention has been completed.

[0008] It is an object of the present invention to provide a core-sheath type having a very high flexibility and hand by combining a high-density polyethylene resin and a linear low-density polyethylene in a specific weight ratio to form a sheath component, and further comprising a polypropylene resin as a core component. It is an object of the present invention to provide a composite long-fiber nonwoven fabric and a method for producing the nonwoven fabric having good spinnability and spreadability and having the above-described properties.

[0009]

Means for Solving the Problems The first aspect of the present invention is that the fineness formed from a composite filament consisting of a core component and a sheath component is 1 to 1.
In a non-woven fabric made of 10 denier, the core component is JI
230 measured by the method described in S K 7210
The melt flow rate under the conditions of a temperature of 2.degree. C. and a load of 2.16 kg is made of polypropylene having a melt flow rate of 10 to 100 g / 10 min, and the sheath component has a Q value defined by a value obtained by dividing the weight average molecular weight by the number average molecular weight of 4.5 or less. With a density of 0.945
0.98 g / cm ³ high density polyethylene 20-8
0% by weight and a density of 0.850 to 0.940 g / cm ³
Characterized in that it is a mixed resin with 80 to 20% by weight of a linear low-density polyethylene of the formula (1).
A second aspect of the present invention is the composite long-fiber nonwoven fabric according to the first aspect of the present invention, wherein the weight ratio of the sheath component to the fiber cross-sectional area orthogonal to the fiber axis is 20 to 80% by weight.

A third aspect of the present invention is that two or more kinds of thermoplastic resins having different core components and sheath components are simultaneously melt-extruded from two spinning outlets and spun, and the spun continuous filament group is subjected to high-speed air by an ejector. After drawing, the web is formed by charging and spreading, then collecting and depositing it on a moving support to form a web, and then fusing and bonding the web under heat and pressure to obtain a long fiber. In a method for producing a core-sheath type composite long-fiber nonwoven fabric in which cores are fused together, a melt flow rate at a core component of 230 ° C. and a load of 2.16 kg measured by a method described in JIS K 7210 is 10 to 100 g /. J composed of polypropylene having a range of 10 minutes, wherein the sheath component has a Q value of 4.5 or less defined by a value obtained by dividing the weight average molecular weight by the number average molecular weight,
190 measured by the method described in IS K7210.
At a melt flow rate of 10 to 70 g / 10 min.
0.98 g / cm ³ high density polyethylene 20-8
0 wt%, a melt flow rate of 10 to 70 g / 10 min and a density of 0.850 to 0.940 g / cm ³ under the conditions of 190 ° C. and a load of 2.16 kg measured by the method described in JIS K7210. It is composed of a mixed resin of 80 to 20% by weight of linear low-density polyethylene, and the difference in melt flow rate between the mixed resin of the core component resin and the mixed resin of the sheath component is combined within the range of 0 to 35 g / 10 minutes,
A method for producing a core-sheath type composite nonwoven fabric, characterized in that melt spinning is performed at a melt spinning temperature of 220 to 270 ° C.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The thermoplastic high-density polyethylene resin used as the first component of the sheath component of the composite filament in the present invention has a value obtained by dividing the weight average molecular weight by the number average molecular weight (weight average molecular weight / number average molecular weight). The Q value defined as (molecular weight) must be below 4.5, preferably below 4.3. The Q value is defined as gel permeation chromatog
raphy: GPC) is the ratio between the weight molecular weight and the number average molecular weight of the polymer, which indicates the distribution width of the molecular weight of the resin, and is used when melt-spinning a thermoplastic resin by a melt extruder. It is known that this greatly affects the suitability and processability of filaments. That is, when the Q value increases, the width of the molecular weight distribution increases, and the resin is melt-spun in a melt extruder,
When elongating the spun filament group, the viscosity of the resin becomes too large, and the spinnability decreases. When the Q value of the high-density polyethylene exceeds 4.5, yarn breakage frequently occurs during melt spinning, and it is difficult to produce a composite filament having a fineness of 10 denier or less, which is not suitable. Although there is no particular limitation on the lower limit of the Q value, if it is 2.5 or less, it is difficult to control the synthesis conditions for producing the polymer, and it is not easy to obtain a resin. The lower limit is 2.5.

The density of the high-density polyethylene is:
0.945 to 0.970 g / cm ³ , preferably 0.9
It is in the range of 50 to 0.965 g / cm ³ . Density is 0.
When a polyethylene polymer of less than 945 g / cm ³ is used, the core obtained by melt-spinning using the resin as the first component of the sheath component in the resin combination of the present invention.
When the sheath-type composite long fiber is charged and opened, the charge amount is reduced, the spreadability is reduced, and the texture of the obtained composite long-fiber nonwoven fabric is deteriorated, which is not suitable. On the other hand, a high-density polyethylene resin having a density exceeding 0.970 g / cm ³ is not suitable because it has poor flexibility and is difficult to obtain in the market. The density of the linear low-density polyethylene used as the second component of the sheath component of the composite long fiber is 0.850 to
0.940 g / cm ³ , preferably 0.855 to 0.9
It is in the range of 38 g / cm ³ . 0.850g / c density
When a polyethylene polymer having a molecular weight of less than m ³ is used, in the combination of the resin of the present invention, when the core-sheath type composite long fiber used as the second component of the sheath component is charged and opened, the charge amount is increased. , The openness of the fiber is reduced, and the texture of the obtained composite long-fiber nonwoven fabric deteriorates. On the other hand, in the case of a linear low-density polyethylene resin having a density exceeding 0.940 g / cm ³ , the linear low-density polyethylene This is not suitable because the characteristic soft touch feeling is lost and the resulting nonwoven fabric becomes less flexible.

In the present invention, the thermoplastic high-density polyethylene resin and the linear low-density polyethylene used as the sheath component of the composite long fiber are respectively JIS K6.
190 ° C., load 2. Measured by the method described in 760.
Melt flow rate (MFR) under the condition of 16 kg is 10 to 70 g / 10 min, preferably 10 to 50 g / 10 min.
g / 10 minutes. High-density polyethylene and linear low-density polyethylene having an MFR of less than 10 g / 10 minutes cannot be easily melt-spun at a high speed unless the melting temperature is extremely high during spinning. Spinning at a high temperature tends to cause stains on the spinneret surface, which is not preferable in operation. On the other hand, if the MFR exceeds 70 g / 10 minutes, thread breakage is likely to occur, and not only the texture of the obtained composite long-fiber nonwoven fabric decreases, but also the strength decreases, which is not suitable.

In the present invention, the sheath component of the composite long fiber is 20 to 80% by weight of a high-density polyethylene resin and 80% by weight.
A mixed resin with 〜20% by weight linear low density polyethylene is used. When the weight ratio of the linear low-density polyethylene is less than 20% by weight, the spreadability of the fiber becomes high, but the extremely low thermal melting property and the extremely excellent thermal adhesiveness and flexibility obtained from the soft touch of the linear low-density polyethylene are obtained. Can't embody. vice versa,
When the linear low-density polyethylene weight ratio exceeds 80% by weight, the heat adhesion and flexibility become extremely high, but the fiber opening property becomes poor. In addition, the mixed resin of the sheath component high-density polyethylene and linear low-density polyethylene includes a lubricant, a pigment,
An additive such as a stabilizer, a flame retardant, or an antibacterial agent may be contained and used.

In the present invention, the polypropylene used as the core component has a Q value in the range of 2.0 to 3.5,
230 measured by the method described in IS K 7210
The MFR under the conditions of a temperature of 2.degree.
0 g / 10 min, preferably in the range of 30 to 80 g / 10 min. Polypropylene having a Q value of less than 2.0 is difficult to obtain because it is difficult to produce, and those having a Q value of more than 3.5 cause yarn breakage. Polypropylene having an MFR of less than 10 g / 10 minutes is not preferable in terms of operation because melt spinning at a high speed becomes difficult unless the melting temperature is increased, and the spinning at a high temperature easily causes stains on a die surface. . Conversely, if the MFR exceeds 100 g / 10 minutes, thread breakage is likely to occur, and not only the hand of the resulting composite long-fiber nonwoven fabric is reduced, but also the strength is reduced, which is not suitable. Further, the polypropylene may contain additives such as a lubricant, a pigment, a stabilizer, and an antibacterial agent, as in the case of the sheath polyethylene.

In the present invention, the total weight ratio of the sheath component high-density polyethylene and the linear low-density polyethylene to the fiber cross-sectional area orthogonal to the fiber axis of the composite long fiber constituting the nonwoven fabric is 20 to 80% by weight. It is. The total weight ratio of high-density polyethylene and linear low-density polyethylene is 2
If the amount is less than 0% by weight, the fiber strength is increased, but the adhesive strength is weakened, and the strength of the obtained nonwoven fabric is too weak to be practically suitable. Conversely, the total weight ratio of high-density polyethylene and linear low-density polyethylene is 80% by weight.
If it exceeds, 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 to be suitable. The fineness of the composite filament used in the present invention is 1 to 10
Denier range. If the fineness of the long fiber exceeds 10 denier, the fiber diameter becomes too large, the resulting nonwoven fabric becomes hard and the texture decreases, and it is difficult to produce a fine fiber having a fineness of less than 1 denier. The cross-sectional shape of the composite long fiber may be irregular or flat in addition to the circular cross-section.

The basis weight of the composite nonwoven fabric of the present invention is in the range of 5 to 150 g / m ² . Weight is 150g
If it exceeds / m ² , the nonwoven fabric becomes too hard and the texture deteriorates, and if the basis weight is less than 5 g / m ² , the strength of the nonwoven fabric becomes too low and it becomes difficult to stably produce the nonwoven fabric.
The present invention is a melt extruder for a known composite filament, in which a different thermoplastic resin is melt-extruded and spun, and a nonwoven fabric formed of a composite filament composed of a core component and a sheath component, and a method for producing the same, The sheath component is a mixed resin of a specific high-density polyethylene and a linear low-density polyethylene, and the core component is composed of a specific polypropylene, and the difference between the respective MFRs is within a range of 0 to 35 g / 10 minutes. Combined and the melt spinning temperature is 220-27
The melt-extruded and spun at the same temperature selected from the range of 0 ° C., the spun continuous filament is taken out by an ejector at a high speed, the fineness of the composite filament becomes 1 to 10 denier, The web is formed by collecting and depositing on a moving collecting support, and then heat-bonded.

The melt spinning temperature in the present invention is from 220 to
Each resin needs to be melt-spun at the same temperature selected from the range of 270 ° C. However, if the spinning temperature is out of the above range, the spinning condition becomes poor, and it becomes difficult to obtain a satisfactory nonwoven fabric. . That is, when the spinning temperature is lower than 220 ° C., a high air pressure is required to increase the spinning speed, and it is difficult to obtain a fiber having a fineness of 1 to 10 denier without causing yarn breakage. Conversely, the spinning temperature is 270 ° C
If it exceeds, the strength of the spun filament is weakened and not only is it easy for yarn breakage to occur easily, but also the nozzle surface becomes easy to become dirty, and the yarn breakage due to the nozzle surface dirt increases after a long operation, making it suitable. Absent. The same temperature selected from the above range during melt spinning, in the present invention,
It means that the respective resins of the core component and the sheath component are spun at substantially the same melt spinning temperature, and the temperature is ± 1.5 ° C., preferably ± 1.0 ° C. within the range of the melt spinning temperature. Permissible. When the absolute value of the difference between the melt spinning temperatures of the core component resin and the sheath component resin exceeds 3 ° C., the cooling of the composite yarn after melt extrusion is not smooth, and the cooling to the yarn is uneven. Since distortion remains, good spinnability cannot be realized, and eventually yarn breakage occurs, and the nonwoven fabric becomes non-uniform.

In the present invention, the difference in MFR between the high-density polyethylene of the sheath component and the linear low-density polyethylene and all the differences between the MFR and the MFR of the polypropylene of the core component are 0 to 35 g / 10 min. For the first time, the melt spinning at the same temperature selected from the above melt spinning temperature range makes the cooling of the composite filament filament after melt extrusion smooth for the first time, and at the joint of the core and sheath due to uneven cooling. Since no displacement occurs and no distortion due to the difference in melt elongation characteristics remains, good spinnability can be realized. After the high-density polyethylene of the sheath component, the linear low-density polyethylene and the polypropylene of the core component are extruded and spun at the same temperature from the respective spinnerets of the melt-extruding spinning machine, they are drawn by high-speed air by an ejector and stretched. Then, the formed long fibers are frictionally charged by being applied to a collision plate, and the fibers are opened by repulsion by the electric charge. In this case, corona discharge treatment can be performed as a charging method.

Next, the group of long filaments uniformly spread is collected and deposited on an endlessly rotating mesh support for collection to form a web.
In this way, the web can be formed very easily even with fine denier conjugate filaments, and the composite filaments whose surface is composed of polypropylene and high-density polyethylene having extremely excellent texture as a sheath component have a low yarn breakage rate. And can be obtained by high-speed spinning. In the present invention, a large number of long fibers collected on a support are formed into a web, and the web is further provided with self-fused areas of the fibers at regular intervals, so-called hot embossing for heat bonding. Is applied. The thermal bonding of the long fibers by the hot embossing is performed by introducing the web between the uneven roll and the smooth roll which have heated the web, and performing heating and pressurizing treatments, whereby the fibers of the nonwoven fabric corresponding to the convex portions of the uneven roll are heated. Are formed by fusing. In this case, the temperature of the roll is maintained at 3 to 20C, preferably 5 to 15C lower than the melting point of the low-density polyethylene as the sheath resin. When the difference between the roll temperature and the melting point of the resin is less than 3 ° C., the fibers adhere to the roll during thermocompression treatment by the roll, which is not suitable because it causes a manufacturing trouble. Conversely, if the difference between the roll temperature and the melting point of the resin exceeds 20 ° C., the formation of the fused portion becomes insufficient,
Not only is the strength of the nonwoven fabric significantly reduced, but also the fluff is undesirably severe.

The pressure when the thermocompression treatment is performed with the uneven roll and the smooth roll is 10 to 80 kg / cm, preferably 2 kg / cm.
0 to 60 kg / cm. If the pressure is less than 10 kg / cm, the formation of the fusion zone by the thermocompression treatment may be insufficient, and if it exceeds 80 kg / cm, the self-fusion zone becomes a film and the texture of the nonwoven fabric is impaired. There is. As a method for forming the fusion zone, a web composed of a group of continuous continuous filament fibers is introduced between a concavo-convex roll and an ultrasonic horn, and subjected to ultrasonic treatment, so that a point fusion corresponding to the convex portion is performed. It is also possible to form the attachment part. In the present invention, the area of the individual fusion zones is in the range of 0.03 to ⁴ mm2. If the area of the fusion zone is less than 0.03 mm ² , the strength of the nonwoven fabric is insufficient, which is not preferable. Conversely, if the fused area exceeds 4 mm ² , the resulting nonwoven fabric becomes too hard. The total area of the fusion zone is 2 to 30 area% of the total surface area of the composite long-fiber nonwoven fabric. If the total area of the fusion zone is less than 2% by area,
When the strength of the nonwoven fabric is insufficient and the area of the fusion zone exceeds 30 area%, the nonwoven fabric becomes hard.

As described above, the composite long-fiber nonwoven fabric comprising the high-density polyethylene and the linear low-density polyethylene as the sheath component and the polypropylene as the core component of the present invention has excellent spinnability and spreadability upon production, and has excellent properties. It has flexibility and feel, and is processed variously as needed, sanitary materials,
Used as medical substrates, clothing substrates, household substrates, industrial substrates, and the like.

[0023]

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,% is% by weight unless otherwise specified.

Example 1 MFR 25 g / 10 min, density 0.955 g / cm ³ , Q
50% of high-density polyethylene resin (manufactured by Mitsubishi Chemical Corporation) having a value of 3.5 and a melting point of 127.8 ° C., an MFR of 20 g / 10 minutes, a density of 0.895 g / cm ³ , a Q value of 2.8 and a melting point of 102.5 ° C.
50% linear low density polyethylene resin (Mitsubishi Chemical Corporation)
A mixed resin consisting of
A polypropylene resin (manufactured by Mitsubishi Chemical Corporation) having a Q value of 3.0 was prepared as a core component. Next, using a core-sheath composite spinneret in a melt extruder, the weight ratio of the sheath component to the fiber cross section orthogonal to the fiber axis of the composite long fiber constituting the nonwoven fabric was set to 30%, and the above-mentioned resin was used in each case for 250%. ± 1
After heating to ℃ and melting, extruding through a number of micropores and spinning, the spun filaments are stretched and drawn by high-speed air with an ejector, and spread on a moving wire collecting support. It was collected and deposited to form a web. Next, the web was introduced between a concavo-convex roll and a smooth roll heated to 97 ° C., and a linear pressure of 40 kg / cm.
Then, a portion corresponding to the convex portion of the concave-convex roll was fused to obtain a composite long-fiber nonwoven fabric having a basis weight of 40 g / m ² . The area of each fusion zone is 0.12 mm ²
The total area of the fused areas was 4 area% based on the total surface area of the nonwoven fabric, and the fineness of the composite filament was 3 denier.

The spinnability and the formation, flexibility and tensile strength of the obtained long-fiber nonwoven fabric were tested and evaluated by the following test methods. Test Method (1) Spinnability: The spinnability of the resin was evaluated based on the amount of yarn breakage during melt spinning. The evaluation was performed in the following five stages. 5 ... No yarn breakage, and spinning properties are extremely good. 4: There is almost no yarn breakage, and the spinnability is good. 3: There is a little yarn breakage, but there is no problem and the spinnability is normal. 2 ... Yarn breakage is considerable and spinnability is poor. 1: Very many yarn breaks and spinning properties are extremely poor. (2) Formation: The formation of the obtained long-fiber nonwoven fabric was evaluated organoleptically. The evaluation was performed 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: Flexibility of the obtained long-fiber nonwoven fabric was evaluated organoleptically. The evaluation was performed in the following five stages. 5 ... The flexibility is extremely good. 4: Good flexibility. 3 ... Flexibility is normal. 2 ... Poor flexibility. 1 ... very poor flexibility. (4) Tensile strength: Performed according to the method shown in JIS L 1906.

Example 2 MFR 20 g / 10 min, density 0.960 g / cm ³ , Q
50% by weight of a high-density polyethylene resin (manufactured by Mitsubishi Chemical Corporation) having a value of 4.0 and a melting point of 133.0 ° C., and an MFR of 30 g / 10 min.
Density 0.930 g / cm ³ , Q value 3.7, melting point 125.
3 ° C linear low-density polyethylene resin (Mitsubishi Chemical Corporation) 5
A mixed resin consisting of 0% by weight was used as a sheath component, and MFR 50 g
A polypropylene resin (manufactured by Mitsubishi Chemical Corporation) having a Q value of 2.7 was prepared as a core component. Next, using a core-sheath composite spinneret in a melt extruder, the weight ratio of the sheath component in the fiber cross section orthogonal to the fiber axis of the composite long fiber constituting the nonwoven fabric was set to 30%, and each of the resins was 240
After heating and melting to ± 0.5 ° C, extruding and spinning from a number of micropores, the spun filaments are stretched while being pulled by an ejector with high-speed air, and the fiber is stretched and opened. It was collected and deposited on a support to form a web. Next, the web was introduced between the uneven roll and the smooth roll heated to 115 ° C.
By applying heat embossing at 0 kg / cm and fusing a portion corresponding to the convex portion of the concave-convex roll, the basis weight is 14 g / m ^2.
Was obtained. The area of the individual fused areas is 1.0 mm ² , the total area of the fused areas is 15 area% based on the total surface area of the nonwoven fabric, and the fineness of the composite filament is 2.
It was 8 denier. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Example 3 Except that each of the resins was heated to 260 ± 1 ° C. and melted and extruded from a large number of fine holes, the resin was extruded from a large number of fine holes and spun. The ejected filament group was stretched and drawn while being taken up by an ejector with high-speed air, and collected and deposited on a moving wire-made collecting support to form a web. Then
This web was introduced between a concavo-convex roll and a smooth roll heated to 96 ° C., subjected to hot embossing at a linear pressure of 60 kg / cm, and fused to a portion corresponding to the convex portion of the concavo-convex roll to obtain a basis weight of 50 g / m 2. A composite long fiber nonwoven fabric of No. ² was obtained. The area of each of the fused areas was 2.0 mm ² , the total area of the fused areas was 10 area% based on the total surface area of the nonwoven fabric, and the fineness of the composite filament was 7.5 denier. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Example 4 Except that the resin was heated to 230. +-. 0.5.degree. C. and melted, respectively, and extruded from a large number of fine holes, the resin was extruded from a large number of fine holes and spun. The spun filament group was stretched and drawn while being taken up by an ejector with high-speed air, and collected and deposited on a moving wire-made collecting support to form a web. Next, the web was introduced between a concavo-convex roll heated at 117 ° C. and a smooth roll, subjected to hot embossing at a linear pressure of 30 kg / cm, and a portion corresponding to a convex portion of the concavo-convex roll was fused to obtain a basis weight of 24 g. / M ² was obtained. The area of each fusion zone is 0.28 mm ² , and the total area of the fusion zone is 8 area% based on the total surface area of the nonwoven fabric.
The fineness of the composite filament was 2.5 denier. The spinnability and the obtained long-fiber nonwoven fabric were tested by the test method described above,
evaluated.

Example 5 Except that the weight ratio of the sheath component to the fiber cross-sectional area perpendicular to the fiber axis of the composite long fiber constituting the nonwoven fabric was set to 70% using a core-sheath composite spinning die in a melt extruder. Is
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1. The spinnability and the obtained long-fiber nonwoven fabric were tested by the test method described above, and the quality was evaluated.

Example 6 As a sheath resin, MFR 25 g / 10 min, density 0.95
30% by weight of a high-density polyethylene resin (manufactured by Mitsubishi Chemical Corporation) having 5 g / cm ³ , a Q value of 3.5, and a melting point of 127.8 ° C., and an MFR
20 g / 10 min, density 0.895 g / cm ³ , Q value 2.
8, a composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that a mixed resin consisting of 70% by weight of a linear low-density polyethylene resin (manufactured by Mitsubishi Chemical Corporation) having a melting point of 102.5 ° C. was used. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Comparative Example 1 A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that a high-density polyethylene resin for a sheath component having a Q value of 5.0 (manufactured by Mitsubishi Chemical Corporation) was used. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

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

Comparative Example 3 A composite long fiber was prepared in the same manner as in Example 1 except that a mixed resin consisting of 10% by weight of a high-density polyethylene resin and 90% by weight of a linear low-density polyethylene resin was used as the resin for the sheath. A non-woven fabric was obtained. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Comparative Example 4 In a melt extrusion spinning machine, the resin was
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the mixture was melted by heating to 1.5 ° C. and extruded from a large number of micropores. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Comparative Example 5 In a melt extrusion spinning machine, the resin was
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1, except that the mixture was melted by heating to 0.5 ° C. and extruded from a large number of micropores. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Comparative Example 6 In a melt-extrusion spinning machine, the resin was heated and melted, extruded from a number of micropores, and spun, the melting temperature of the sheath component was set to 240 ° C. and the melting temperature of the core component was set to 250 ° C. Except for the above, a composite long-fiber nonwoven fabric was obtained in the same manner as in Example 1. The spinnability and the obtained long-fiber nonwoven fabric were tested and evaluated according to the test method described above.

Comparative Example 7 Except that the weight ratio of the sheath component to the fiber cross-sectional area perpendicular to the fiber axis of the composite long fiber constituting the nonwoven fabric was set to 90% using a core-sheath composite spinneret in a melt extruder. Is
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 2. The spinnability and the obtained long-fiber nonwoven fabric were tested by the test method described above, and the quality was evaluated.

COMPARATIVE EXAMPLE 8 Except that the weight ratio of the sheath component to the fiber cross-sectional area perpendicular to the fiber axis of the composite long fiber constituting the nonwoven fabric was set to 10% using a core-sheath composite spinning die in a melt extruder. Is
A composite long-fiber nonwoven fabric was obtained in the same manner as in Example 2. The spinnability and the obtained long-fiber nonwoven fabric were tested by the test method described above, and the quality was evaluated.

Comparative Example 9 A composite filament nonwoven fabric was obtained in the same manner as in Example 1 except that the fineness of the composite filament was changed to 12 denier. The spinnability and the obtained long-fiber nonwoven fabric were tested by the test method described above, and the quality was evaluated.

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

[0041]

[Table 1]

As is clear from Table 1, according to the present invention, when the resin is melt-spun in a melt-extruding spinning machine, there is no thread breakage and the spinning properties are extremely excellent. Good, without losing strength,
Extremely excellent formation and flexibility (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, yarn breakage occurs frequently and spinnability is poor (Comparative Example 1), and the weight of the linear low-density polyethylene of the sheath component is low. If the ratio is too high, the spreadability is poor and a composite long-fiber nonwoven fabric having a good texture cannot be obtained (Comparative Example 3). If the MFR of the polypropylene used for the core component is too low,
During the melt spinning, yarn breakage frequently occurred, the spinnability was poor, and the texture was impaired (Comparative Example 2). On the other hand, when the melting temperature is too high (280 ° C.) during melt spinning, yarn breakage is large, spinnability is poor, and flexibility is normal, but openability is poor and formation is poor (comparative). Example 4) On the contrary, when the melt spinning temperature is too low (210 ° C.), the yarn breakage is large and the spinnability is poor, and the formation is normal, but the flexibility is poor (Comparative Example 5).

The melting temperature of the resin of the core component and the sheath component is 10 ° C.
(Core: 250 ° C., sheath: 240 ° C.), yarn breakage is large and spinnability is poor, and formation is normal, but flexibility is poor (Comparative Example 6). When the weight ratio of the sheath component in the fiber cross-sectional area perpendicular 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) In both cases, the strength of the obtained composite long-fiber nonwoven fabric decreases. Further, when the fineness of the composite long fiber is increased (fineness: 12 denier), the spinnability is good, and the strength and texture of the obtained composite long fiber nonwoven fabric are normal, but the flexibility is extremely poor (Comparative Example 9). .

[0044]

According to the present invention, there is provided an effect of providing a core-sheath type composite long-fiber nonwoven fabric which is free from thread breakage, has excellent spinnability, and is extremely excellent in flexibility and formation of the nonwoven fabric, and a method for producing the same.

Claims (3)

[Claims] 1. A nonwoven fabric having a fineness of 1 to 10 deniers formed from a composite filament composed of a core component and a sheath component, wherein the core component is measured at 230 ° C. under a load of 2 measured by a method described in JIS K7210. The melt flow rate under the condition of 0.16 kg is made of polypropylene of 10 to 100 g / 10 min, the sheath component has a Q value defined by a value obtained by dividing the weight average molecular weight by the number average molecular weight of 4.5 or less, and has a density of not more than 4.5. 20 to 80% by weight of high density polyethylene of 0.945 to 0.970 g / cm ³ and a density of 0.850 to
0.940 g / cm ³ linear low-density polyethylene 80
A composite long-fiber nonwoven fabric characterized by being a mixed resin of up to 20% by weight. 2. The composite long-fiber nonwoven fabric according to claim 1, wherein the weight ratio of the sheath component to the fiber cross-sectional area orthogonal to the fiber axis is 20 to 80% by weight. 3. Two or more types of thermoplastic resins having different core components and sheath components are simultaneously melt-extruded from two spinning outlets and spun, and the spun continuous filaments are drawn while being stretched by high-speed air by an ejector. After being charged and opened, and then collected and deposited on a moving support to form a web, the web is melt-bonded under heat and pressure to fuse the long fibers together. In the method for producing a core-sheath type composite long-fiber nonwoven fabric, the core component is JIS K
The melt flow rate at 230 ° C. and a load of 2.16 kg measured by the method described in
Consisting of polypropylene in the range of ~ 100 g / 10 minutes,
The sheath component has a Q value defined by a value obtained by dividing the weight average molecular weight by the number average molecular weight of 4.5 or less, and JIS K721
190 ° C, load 2.16 measured by the method described in No. 0
Melt flow rate under 10 kg condition is 10-70 g
/ 10 minutes, the density is 0.945 to 0.970 g /
20-80% by weight of high density polyethylene of cm ³ , JI
190 measured by the method described in S K 7210
At a melt flow rate of 10 to 70 g / 10 min and a density of 0.850 to 0.1 g under a condition of a temperature of 2.degree.
940 g / cm ³ linear low density polyethylene 80-20
% By weight, and the difference in melt flow rate between the core component resin and the mixed resin of the sheath component is 0 to 35.
g / 10 minutes and the melt spinning temperature is 2
A method for producing a core-sheath type composite nonwoven fabric, which is melt-spun at 20 to 270 ° C.