JP3055288B2 - Stretchable long-fiber nonwoven fabric and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long-fiber nonwoven fabric having a uniform texture and excellent elasticity and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, nonwoven fabrics have been used for various purposes such as clothing, industrial materials, civil engineering and construction materials, agricultural and horticultural materials, living related materials, and medical hygiene materials. Among them, nonwoven fabrics used for medical hygiene materials such as pulp materials and supporters are particularly suitable for following the movement of the human body, or because they are easily adapted to the human body,
Elasticity is required. It is known that crimped fibers having good stretchability can be used as constituent fibers in order to impart stretch to a nonwoven fabric.

[0003] When short fibers are used as crimped fibers, the crimped short fibers can be opened by a carding machine to form a fibrous web, and a stretchable nonwoven fabric can be obtained. However, when long fibers are used as crimped fibers,
The fiber web cannot be obtained by opening with a carding machine. Because the card machine is to open the fiber with the needle cloth roller or the like in which the needle is planted on the surface and to transfer the fiber between the needle cloth roller or the like, in the case of the long fiber which can be said to be an endless continuous fiber, In addition, the fiber cannot be transferred and the card machine cannot be used.

[0004] For example, when a long-fiber nonwoven fabric is obtained by a spun bond method, when melt-spun long fibers are introduced into an air soccer and pulled, and when the long fibers are discharged from the air soccer, the long fibers are discharged by a certain means. To give a fibrous web by applying the same charge to the fibers and opening the fibers by the repulsive force between the long fibers. However, if crimps are applied to the long fibers before introducing them into the air soccer, there is a disadvantage that the long fibers are easily entangled with each other and are difficult to spread. If the spreadability is poor, the texture of the resulting fibrous web is poor, and a homogeneous nonwoven fabric cannot be obtained.

[0005] For this reason, there is a method of obtaining a nonwoven fabric by reducing the crimp when discharging the long fiber from the air soccer, obtaining the fiber web by depositing the long fiber, and then expressing the crimp in the long fiber. Widely known. In this method, the composite melt-spinning is performed to obtain a latently crimped filament having a small amount of crimp, which is introduced into an air soccer, then opened by a conventional method to form a fiber web, and then heat is applied. Thus, the non-woven fabric is obtained by causing the latently crimpable long fibers to exhibit crimp. Here, the latently crimpable long fiber is a composite of two types of polymers having different heat shrinkage ratios in a side-by-side or eccentric sheath-core type, and causes the long fiber to exhibit crimp due to the difference in the heat shrinkage ratio. Things.

However, as described above, since the latently crimpable filaments are obtained by composite melt-spinning of two polymers having different heat shrinkage ratios, after spinning and before discharging from air soccer, When subjected to thermal effects such as cooling,
In some cases, crimps were developed. That is,
Although not as great as crimps developed by heat treatment after obtaining the fibrous web, some crimping may occur before discharge from air soccer. Therefore, even when using latently crimpable filaments, at the time of discharge from air soccer, the filaments are likely to be entangled with each other,
There was a drawback that long fibers were difficult to open.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a composite material comprising a propylene-based polymer having a specific melt flow rate ratio as two types of polymers constituting latently crimpable filaments. Non-crimpable and non-latent crimped fibers consisting only of polypropylene to prevent crimping from appearing before discharge from air soccer after melt spinning and to spin the entanglement between latently crimpable filaments. The purpose is to blend the fiber with the latently crimpable fiber to improve the opening property of the latently crimpable fiber, and to obtain a stretchable long-fiber nonwoven fabric having a uniform texture.

[0008]

That is, the present invention relates to an ethylene-propylene random copolymer component having an ethylene content of 1 to 10% by weight and a melt flow rate of the ethylene-propylene random copolymer component. 1.1-2.0
A propylene polymer having a double melt flow rate is composited in a side-by-side or eccentric sheath-core type, and a composite-type long fiber having crimping of 20 to 80% by weight, and a non-composite-type long fiber consisting of only a polypropylene component 80 to 80% 20% by weight, and a point fusion zone in which the long fibers are fused to each other by melting or softening of the ethylene-propylene random copolymer component. TECHNICAL FIELD The present invention relates to a long-fiber nonwoven fabric and a method for producing the same.

First, in the present invention, an ethylene-propylene random copolymer having an ethylene content of 1 to 10% by weight is prepared. This ethylene-propylene random copolymer is composed of 1 to 10% by weight of ethylene and 99 to 90% of propylene.
% By weight and copolymerized. When the ethylene content is less than 1% by weight,
The heat shrinkage stress of the ethylene-propylene random copolymer decreases, and even if heat treatment is performed on the obtained composite type long fiber, a desired crimp cannot be exhibited, which is not preferable. Conversely, if the ethylene content exceeds 10% by weight, it becomes difficult to form chips at the time of copolymerization, or the viscosity of the ejected fibers at the time of melt spinning becomes large, and a composite type long fiber of fineness is obtained. This is not preferable because the composite type filaments are difficult to be formed or the composite type long fibers are stuck together at the time of fiber opening.
In particular, the preferred ethylene content is between 2 and 5% by weight.
The melt flow rate of the ethylene-propylene random copolymer is preferably from 10 to 100 g / 10 minutes, and particularly preferably from 3 to 100 g / 10 minutes.
Most preferably, it is 0 to 80 g / 10 minutes. If the melt flow rate is less than 10 g / 10 minutes, the degree of polymerization is so high that the melting temperature in the melt spinning step must be set high, and smoke is generated during melt spinning or the spinneret becomes dirty. It will be easier. In addition, when high-speed spinning employed in a general spunbonding method is employed, the running tension of the ejected fiber is high, and it is difficult to perform normal thinning, and it tends to be difficult to obtain a composite long fiber having a fineness. Conversely, if the melt flow rate exceeds 100 g / 10 min, the ejected fibers cannot withstand the deformation stress during melt spinning, and tend to break easily. Further, the heat shrinkage stress of the ethylene-propylene random copolymer is reduced, so that even if the conjugated long fiber is heat-treated, the crimp tends to hardly develop. In addition,
In the present invention, the melt flow rate is ASTM D1238 (L)
Was measured by the method described in 1.

On the other hand, a propylene polymer is also prepared. The melt flow rate of this propylene polymer is 20-120 g
/ 10 min, and most preferably 40 to 90 g / 10 min. If the melt flow rate is less than 20 g / 10 minutes, the degree of polymerization is so high that the melting temperature in the melt spinning step must be set high, and smoke is generated during melt spinning, or the spinneret becomes dirty. It will be easier. In addition, when high-speed spinning employed in a general spunbonding method is employed, the running tension of the ejected fiber is high, and it is difficult to perform normal thinning, and it tends to be difficult to obtain a composite long fiber having a fineness. Conversely, the melt flow rate is 120g / 10
If the length exceeds the limit, the ejected fiber cannot withstand the deformation stress during melt spinning, and tends to be easily broken.

What is important in the present invention is that the melt flow rate of the propylene polymer is 1.1 to the melt flow rate of the ethylene-propylene random copolymer.
That is to 2.0 times. Particularly preferably, 1.2 to 1.
6 The melt flow rate of the propylene polymer is 1.1
If it is less than twice, the difference in heat shrinkage characteristics between the two polymers will be small, and even if heat treatment is performed on the obtained composite type long fiber, a desired crimp cannot be exhibited. Conversely, if the melt flow rate of the propylene polymer exceeds 2.0 times, the difference in heat shrinkage characteristics between the two polymers will increase, and during melt spinning, the kneading of the ejected fibers will increase, impairing the spinnability. Not preferred. Also, the number of crimps of the composite type filament immediately after melt-spinning becomes relatively large, and the opening property at the outlet of air soccer becomes poor, which is not preferable.

Using the ethylene-propylene random copolymer component and the propylene polymer prepared as described above, composite melt spinning is performed to obtain a composite type long fiber. This composite type long fiber is latently crimpable, and is crimped by performing a heat treatment later. However, since the ethylene-propylene random copolymer and the propylene polymer have different heat shrinkage properties, there is a possibility that the composite type long fiber may be crimped before the heat treatment.
It is preferable that the crimps not exceeding. The composite form may be a parallel type or an eccentric sheath-core type. In particular, it is preferable to use the parallel type illustrated in FIGS. 2 and 3 or the eccentric sheath-core type illustrated in FIG. In the case of an eccentric sheath-core type, an ethylene-propylene random copolymer component is used as a sheath component. This is because the ethylene-propylene random copolymer component becomes an adhesive between the long fibers and must be exposed on the surface. In particular,
When the difference in melt flow rate between the ethylene-propylene random copolymer component and the propylene polymer is large,
It is preferable that the composite form is an eccentric sheath-core type so that kneeling is less likely to occur during melt spinning. When the eccentric sheath-core type is used, the eccentricity defined by the following equation (a) is preferably 15 or more. If the eccentricity is less than 15, the crimp development during heat treatment tends to decrease. Eccentricity = [(distance between center of diameter of long fiber cross section and center of diameter of core component) x 100] / [(diameter of cross section of long fiber) / 2]
… (A)

[0013] Simultaneously with obtaining the conjugated long fiber as described above, a non-conjugated long fiber comprising only the polypropylene component is melt-spun. This polypropylene component may be the same as or different from the propylene polymer used to obtain the composite long fiber. This non-composite long fiber can be obtained by a conventionally known melt spinning method. The cross-sectional shape of the conjugate long fiber or the non-composite long fiber is not limited to a round shape, but may be an irregular shape or a hollow shape. The fineness of the conjugate long fiber or the non-composite long fiber is an item that can be arbitrarily determined, but is preferably 6 denier or less so as not to impair the flexibility of the obtained elastic long fiber nonwoven fabric. The ethylene-propylene random copolymer component, the propylene polymer component or the polypropylene component may include any of matting agents, pigments, flame retardants, deodorants, antistatic agents, antioxidants, ultraviolet absorbers and the like. Additives may be added.

The conjugated filaments and the non-composite filaments obtained by melt spinning are cooled by a blowing air using a conventionally known cooling device such as a lateral spray or an annular spray, and then introduced into an air soccer. Is done. Both filaments are drawn by air soccer and are drawn and thinned to the desired fineness. The traction speed is preferably 2000 m / min or more, most preferably 30 m / min.
00 m / min or more. When introduced to air soccer,
The fiber is mixed at a ratio of 20 to 80% by weight of the composite type long fiber and 80 to 20% by weight of the non-composite type long fiber. In particular, composite type long fiber 40-60% by weight
It is preferred that the fibers are mixed at a ratio of 60 to 40% by weight of the non-composite long fibers. If the blending ratio of the non-composite filament exceeds 80% by weight, the amount of the composite filament becomes relatively small, and the amount of the crimped filament that appears in the composite filament by heat treatment decreases, and the non-woven fabric becomes nonwoven. This is not preferable because good elasticity cannot be given to the film. Conversely, if the blending ratio of the non-composite filaments is less than 20% by weight, entanglement between the composite filaments having a slight crimp cannot be effectively prevented even before the heat treatment, It is not preferable because the spreadability becomes poor.

[0015] The composite long fiber and the non-composite long fiber are simultaneously introduced into the air soccer and pulled, and both the long fibers are discharged from the outlet of the air soccer. After discharging, the same charge is applied to both filaments by a conventionally known method such as a corona discharge method or a triboelectric charging method for applying a high piezoelectric field, and the filaments are opened. Thereafter, both filaments are deposited on a collection conveyor to obtain a fibrous web. Heat is applied to the spaced spot areas of the fibrous web.

As a method of applying heat to the point area, a heated concavo-convex roll, a heated or room-temperature smooth roll,
Alternatively, it may be performed by introducing a fibrous web between the heated uneven roll and the heated or normal temperature uneven roll. In this way, the area of the fiber web abutting on the convex portion of the uneven roll becomes a point area. At this time, the heating temperature of the concave-convex roll is preferably set to a temperature equal to or lower than the melting point of the ethylene-propylene random copolymer. When the ethylene-propylene random copolymer is heated to a temperature exceeding the melting point, even in an area other than the point area corresponding to the convex portion of the uneven roll, the ethylene-propylene random copolymer may be melted or softened. . The heating temperature of the concavo-convex roll is preferably ethylene-
The temperature is preferably 30 to 5 ° C. lower than the melting point of the propylene random copolymer. When the temperature of the concavo-convex roll is higher than the temperature lower by 5 ° C. than the melting point of the ethylene-propylene random copolymer, the ethylene-propylene random copolymer is melted or softened even in areas other than the point areas as described above, The feeling of the obtained nonwoven fabric becomes hard, and the flexibility tends to decrease. Conversely, the temperature of the concavo-convex roll is 30 ° C. higher than the melting point of the ethylene-propylene random copolymer.
If the temperature is set lower than the low temperature, the ethylene-propylene random copolymer does not melt or soften even in the point area, and there is a tendency that the fusion between the long fibers becomes difficult. In the present invention, the melting point of the ethylene-propylene random copolymer and other polymers, the differential scanning calorimeter DSC-2 manufactured by Perkin Elmer Co., using a heating rate of 20
It is the temperature that gives the extreme value of the melting absorption curve measured in ° C./min.

As a method of applying heat to the point area,
This may be performed by introducing a fibrous web into the surface of the uneven roll that oscillates ultrasonic waves from the convex portions. At this time, in the area of the fiber web in contact with the projection, the long fibers rub against each other,
The frictional heat causes the ethylene-propylene random copolymer to melt or soften. This ultrasonic method does not require a large pressure to be applied to the point area, unlike the case of using the above-mentioned heated uneven roll. Therefore, the flexibility of the obtained elastic long-fiber nonwoven fabric is not easily reduced, so that it is preferable. The shape of the tip of the convex portion of the heated concave-convex roll or the convex portion of the concave-convex roll that oscillates ultrasonic waves is round, elliptical, rhombic, triangular,
Any shape such as a T-shape and a well-shape can be adopted.

As described above, by applying heat to the point area of the fibrous web, the ethylene-propylene random copolymer is melted or softened, and then solidified, thereby fusing between the long fibers to form a dot. Obtain a fusion zone.
The ratio of the total area of the point fusion zone is preferably 3 to 40% based on the area of the fiber web. When the ratio of the total area of the point fusion areas is less than 3%, the fusion areas between the long fibers are small, and the resulting nonwoven fabric tends to have poor shape retention and mechanical properties. On the other hand, if the ratio of the total area of the point fusion areas exceeds 40%, the fusion area between the long fibers tends to be too large, and the flexibility of the obtained nonwoven fabric tends to decrease.

At the same time as the formation of the point fusion zone, or after the formation of the point fusion zone, heat treatment is performed to cause the composite type long fiber to exhibit crimp. As a method of performing the heat treatment at the same time as the formation of the point fusion zone, when the fibrous web is introduced into the heated uneven roll, the radiant heat from the concave portion can be applied to the fibrous web. In addition, as a method of heat treatment after forming the point fusion zone, the fibrous web having the point fusion zone formed can be introduced into a hot air circulation type heat treatment machine. At this time, the temperature of the hot air is
Although it depends on the mode of the heat treatment machine and the introduction speed and introduction time into the hot air treatment machine, it is generally preferable to set the temperature to a temperature lower than the melting point of the ethylene-propylene random copolymer and lower by 30 ° C. than the melting point. As described above, it is possible to obtain a stretchable long-fiber nonwoven fabric having a point fusion zone and crimping of the conjugate long fiber in an area other than the point fusion zone. The expressed number of crimps is preferably from 6 to 100/25 mm, and most preferably from 20 to 80/25 mm. In addition, the basis weight of the obtained elastic long-fiber nonwoven fabric is generally 150 g /
m ² or less, but may be about 500 g / m ² for a thick product.

One embodiment of the method for producing a stretchable long-fiber nonwoven fabric according to the present invention is as shown in FIG. That is, the spinning device melts and extrudes the propylene polymer and measures it (in this case, the same polymer is used as the propylene polymer of the composite type long fiber and the polypropylene of the non-composite type long fiber). And a measuring section 2 for melt-extruding and measuring the ethylene-propylene random copolymer. Then, each is introduced into the spinneret 3, and the ethylene-propylene random copolymer component and the propylene polymer component are composited and subjected to composite melt spinning, and the composite type long fiber 4 is spun out. Further, the propylene polymer (polypropylene) is melt-spun alone, and the non-composite long fiber 4 is spun out. Each spun long fiber 4 is cooled by a cooling device 5 and then introduced into an air soccer 6 to be pulled. Therefore, the composite type long fibers and the non-composite type long fibers are mixed at a predetermined ratio. At the outlet of the air soccer 6, a corona discharge opening device 7 capable of forming a high piezoelectric field is attached. When passing through the corona discharge opening device 7, each long fiber 4 is charged to the same charge and spread. Is done. Then, the long fibers 4 are deposited on the moving collection conveyor 8 to form the fiber web 9. This fiber web 9 is introduced into an embossing device composed of a heated uneven roll 10 and a smooth roll,
In the point area of the fiber web 9 abutting on the convex part of the uneven roll 10, the ethylene-propylene random copolymer component is melted or softened, and the long fibers 4 are fused together to form a point fusion area. You. Thereafter, the fiber web 9 is introduced into the heat treatment machine 11 while being kept in a relaxed state between the pair of rolls 12 and the pair of rolls 13. At this time, crimps appear in the composite type long fiber, and a long-fiber nonwoven fabric excellent in elasticity can be obtained. This stretchable long-fiber nonwoven fabric is wound up as a product roll 15 by the winder 14.

The stretchable long-fiber nonwoven fabric according to the present invention preferably has the following physical property values. That is, 30%
The elongation recovery rate during elongation is preferably 20% or more in both length and width. Here, the elongation recovery rate at 30% elongation is determined by the following measuring method. That is, using Toyo Baldwin Tensilon UTM-4-1-100, JISL-
According to the strip method described in 1096A, a tensile test was performed on a sample piece having a sample width of 5 cm and a sample length of 10 cm at a tensile speed of 10 cm / min, and a strength-elongation curve at an elongation of 30% was drawn (FIG. 7). E
Line), and then release the tension from the specimen to increase the strength of the specimen-
An elongation curve was drawn (R line in FIG. 7). Then, the area (X) of the dotted line portion and the area (Y) of the hatched portion shown in FIG.
It is obtained by the following equation. That is, the elongation recovery rate (%) at the time of 30% elongation = 100Y / (X + Y). The length of the nonwoven fabric refers to the direction in which the machines are arranged during the production of the nonwoven fabric, and the width of the nonwoven fabric refers to a direction orthogonal to the longitudinal direction. If the elongation recovery rate at 30% elongation is less than 20% in either the vertical or horizontal direction of the nonwoven fabric, there is a tendency that sufficient elasticity cannot be obtained.

The stretchable long-fiber nonwoven fabric according to the present invention preferably has a compression stiffness of 80 g or less. The compression stiffness indicates the flexibility of the nonwoven fabric, and the smaller the value of the compression stiffness, the higher the flexibility. here,
The compression stiffness is measured by the following method. That is, a sample width of 50 mm was taken in the machine direction of the nonwoven fabric (vertical direction of the nonwoven fabric), and five sample pieces having a sample length of 100 mm in a direction perpendicular to this direction were prepared. After bending in the direction to form a cylindrical shape and joining both ends thereof to prepare a sample, Toyo Baldwin Co., Ltd. Tensilon UTM-4-1-
Using 100, the sample was compressed in the width direction of the sample at a compression speed of 50 mm / min, the stress at the maximum load was measured, and the average value was defined as the compression softness. When the compression stiffness of the nonwoven fabric exceeds 80 g, the flexibility of the nonwoven fabric is reduced, and a tendency to appear coarse and hard appears. The compression stiffness is particularly preferably 50 g or less, and most preferably 30 g or less.

The stretchable long-fiber nonwoven fabric according to the present invention preferably has an apparent density of 0.1 g / cm ³ or less.
The apparent density indicates the bulkiness of the nonwoven fabric, and the smaller the value, the higher the bulkiness. Here, the apparent density is measured by the following method. That is,
Five sample pieces having a sample width of 10 cm and a sample length of 10 cm were prepared, and the basis weight (g / m ² ) of each sample piece was measured. / Cm ² , and the thickness (t) after standing for 10 seconds was measured. The apparent density was calculated by the following equation, and the average value was defined as the apparent density of the nonwoven fabric. Apparent density (g / cm ³ ) = [weight per unit area (g
/ M ² ) / 1000 t (mm)]. 0.1g / apparent density
If it exceeds cm ³ , there is a tendency that sufficient bulkiness cannot be obtained.

[0024]

Next, the present invention will be specifically described based on examples. In the examples, the measurement and evaluation of various characteristics were performed by the methods described above, and those not described above were measured and evaluated by the following methods. (1) Tensile strength of long-fiber nonwoven fabric: Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd. was used, and a sample piece having a sample width of 5 cm and a sample length of 10 cm was cut into 10 pieces according to the strip method described in JIS L-1096. Individually prepared, the maximum tensile strength was individually measured at a tensile speed of 10 cm / min, and the average value was converted to a basis weight of 100 g / m ² . (2) Elongation of long-fiber nonwoven fabric: Elongation at the maximum tensile strength measured by the method of (1). (3) Spreadability between long fibers: The openness of the long fibers discharged from the corona discharge spreader provided at the outlet of the air soccer was visually evaluated and evaluated as follows. ：: No bundle of long fibers was observed, and each long fiber was opened. ×: Many bundles of long fibers are observed, and the spread state is poor.

Example 1 First, an ethylene-propylene random copolymer having an ethylene content of 4% by weight, a melting point of 138 ° C. and a melt flow rate of 50 g / 10 minutes was prepared. A propylene polymer having a melting point of 162 ° C. and a melt flow rate of 70 g / 10 minutes was prepared. These polymers are separately charged into an extruder type extruder using a spinning apparatus as shown in FIG. 1, and are melted and weighed. After that, the composite ratio of both polymers was set to 1: 1 and composite melt spinning was performed with a spinneret.
As shown in the figure, a parallel composite type long fiber was obtained. Simultaneously, only the propylene polymer was introduced into the same spinneret and melt-spun to obtain a non-composite long fiber having a round fiber cross section as shown in FIG. In the spinneret, spin holes 105 for composite melt spinning and 105 holes for ordinary melt spinning are alternately arranged. Then, the composite melt spinning and the ordinary melt spinning were performed at a spinning temperature of 210 ° C. while the single hole discharge amount of the spinning holes was set to 1.25 g / min.
The discharged fibers discharged from each spinning hole are mixed and introduced into the air soccer installed below the spinning hole, and while being pulled and pulled, a composite filament and a non-composite filament with a fineness of 2.8 denier are obtained. Was. Then, each filament was passed through a corona discharge region forming a high piezoelectric field provided at the exit of the air soccer to open the fiber. At this time, the composite type long fiber had some crimp, but as shown below, the spreadability was good. After that, each long fiber was deposited on the moving collection conveyor to obtain a fiber web. At this time, the fibrous web was obtained by uniformly mixing the composite type long fibers and the non-composite type long fibers at an equal ratio.

The obtained fibrous web was introduced into an embossing device composed of a concavo-convex roll having a ratio of the total area of the convex portions to the total surface area of the roll of 6% and a smooth roll. The temperature of the uneven roll was 125 ° C., and the linear pressure between the uneven roll and the smooth roll was 30 kg / cm. By introducing the fiber web into this embossing device, the ethylene-propylene random copolymer is melted or softened in the point areas corresponding to the convex portions of the uneven roll, and the long fibers are fused to each other, and the point fusion area is formed. Was formed. At the same time, the heat of the concavo-convex roll is applied to the entire fibrous web, and the number of crimps is 32
A crimp of pieces / 25 mm was developed. The non-composite long fiber is
It had 2 crimps / 25 mm crimps. Various physical properties of the long-fiber nonwoven fabric thus obtained were as follows. Note Opening property of each long fiber: ○ Weight of long fiber nonwoven fabric: 52 g / m ² Strength of long fiber nonwoven fabric: 18.8 kg Elongation of long fiber nonwoven fabric: 68% Elongation recovery rate at 30% elongation of long fiber nonwoven fabric: 27% (vertical) 30% (horizontal) Apparent density of long-fiber nonwoven fabric: 0.048 g / cm ³ Compression softness of long-fiber nonwoven fabric: 25 g

Example 2 The long-fiber nonwoven fabric obtained in Example 1 was further introduced into a hot air circulation type heat treatment machine and heat-treated in a relaxed state. The conditions of the heat treatment were a hot air temperature of 135 ° C. and a treatment time of 1 minute. The composite long fibers in the long-fiber nonwoven fabric thus obtained exhibited crimps of 38 crimps / 25 mm.
On the other hand, the number of crimps of the non-composite filament was 2 as in Example 1.
Pieces / 25 mm. Various physical properties of the long-fiber nonwoven fabric obtained as described above were as follows. Note Weight of long-fiber nonwoven fabric: 50 g / m ² Strength of long-fiber nonwoven fabric: 13.6 kg Elongation of long-fiber nonwoven fabric: 72% Elongation recovery rate at 30% elongation of long-fiber nonwoven fabric: 43% (length) 45% (width) ) Apparent density of long-fiber nonwoven fabric: 0.039 g / cm ³ Compression softness of long-fiber nonwoven fabric: 12 g

Example 3 A non-woven fabric was obtained in the same manner as in Example 1, except that a spinneret having 120 spin holes for composite melt spinning and 90 spin holes for ordinary melt spinning was used. Then, the nonwoven fabric was subjected to a heat treatment under the same conditions as in Example 2. The composite long fiber in the long-fiber nonwoven fabric obtained as described above has a crimp number of 36.
An individual crimp of 25 mm was developed. On the other hand, the number of crimps of the non-composite long fiber was 2/25 mm as in Example 1. Various physical properties of the long-fiber nonwoven fabric obtained as described above were as follows. Note Opening property of long fiber: ○ Weight of long fiber nonwoven fabric: 49 g / m ² Strength of long fiber nonwoven fabric: 12.6 kg Elongation of long fiber nonwoven fabric: 76% Elongation recovery rate at 30% elongation of long fiber nonwoven fabric: 45 % (Vertical) 47% (horizontal) Apparent density of long-fiber nonwoven fabric: 0.036 g / cm ³ Compression softness of long-fiber nonwoven fabric: 10 g

COMPARATIVE EXAMPLE 1 An ethylene-propylene random copolymer having an ethylene content of 4% by weight, a melting point of 138 ° C. and a melt flow rate of 8 g / 10 minutes was used.
A nonwoven fabric was obtained in the same manner as in Example 1 except that the temperature was changed to ° C.
In this case, since the melt flow rate of the polypropylene is 8.75 times the melt flow rate of the ethylene-propylene random copolymer, the knee angle of the fiber discharged from the spinning hole is large, and the surface of the spinneret becomes dirty. It was complicated and the operability was significantly reduced. Also, before being introduced into the air soccer, the composite filaments are crimped at 23 crimps / 25mm, and even if the non-composite filaments are mixed, the composite filaments are not air-sucked. Entangled at the exit,
The spreadability was poor. Further, the number of crimps of the composite type long fiber in the obtained nonwoven fabric was 26 pieces / 25 mm, and the number of crimps of the non-composite type long fiber was 2 pieces / 25 mm. Various physical properties of the nonwoven fabric obtained as described above were as follows. Note Opening property of long fiber: × Weight of long fiber nonwoven fabric: 53 g / m ² Strength of long fiber nonwoven fabric: 16.5 kg Elongation of long fiber nonwoven fabric: 56% Elongation recovery rate at 30% elongation of long fiber nonwoven fabric: 14 % (Vertical) 17% (horizontal) Apparent density of long-fiber nonwoven fabric: 0.078 g / cm ³ Compression softness of long-fiber nonwoven fabric: 38 g

[0030]

As described above, according to the present invention, an ethylene-propylene random copolymer component and a propylene copolymer component having a specific melt flow rate ratio are provided in a parallel type or an eccentric sheath core. Since the composite crimped composite filaments used in the mold are used, there is almost no crimping between the composite melt-spinning and the heat treatment. Therefore, at the time of opening at the outlet of the air soccer, the composite type long fibers are less likely to be entangled with each other, and an effect that the opening property is excellent. In addition, since non-composite filaments having substantially no crimp are introduced into the air soccer together with the composite filaments, the effect that the non-composite filaments can further prevent entanglement of the composite filaments can be obtained. Play. Due to the synergistic effect of the two, at the outlet of the air soccer, both filaments are well spread and then deposited on a collecting conveyor to form a fibrous web. Therefore, in this fibrous web, both long fibers are evenly distributed, and an effect that a fibrous web and a nonwoven fabric with good formation can be obtained.

The long fibers in the fiber web are fused by melting or softening an ethylene-propylene random copolymer component, which is one component of a composite type long fiber compounded in a side-by-side or eccentric sheath-core type, Morphological stability is imparted. And this fusion | melting area | region is a point fusion | melting area | region spaced apart. Furthermore, in areas other than the point fusion area,
Simultaneously with or after the formation of the point-welded area, a heat treatment is performed so that the latently-crimpable conjugated continuous fiber develops crimp. Therefore, the composite type long fiber in the area other than the point fusion area freely expands and contracts, and the long fiber nonwoven fabric has an effect of showing good elasticity. Therefore, the stretchable long-fiber nonwoven fabric according to the present invention can be suitably used for various applications such as clothing, industrial materials, civil engineering construction, agricultural and horticultural materials, life-related materials, and medical hygiene materials. Things.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an apparatus for producing an elastic long-fiber nonwoven fabric according to an example of the present invention.

FIG. 2 is a schematic view showing an example of a cross section of a composite type long fiber used in the present invention.

FIG. 3 is a schematic view showing an example of a cross section of a composite type long fiber used in the present invention.

FIG. 4 is a schematic view showing an example of a cross section of a composite type long fiber used in the present invention.

FIG. 5 is a schematic view showing an example of a cross section of a non-composite long fiber used in the present invention.

FIG. 6 is a schematic diagram showing an example of a cross section of a non-composite long fiber used in the present invention.

FIG. 7 is a strength-elongation curve for explaining the definition of elongation recovery rate at 30% elongation used in the present invention.

[Explanation of symbols]

 4 long fiber 6 air soccer 8 collection conveyor 9 fiber web

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuo Noguchi 23 Uji Kozakura, Uji City, Kyoto Prefecture Inside the Central Research Laboratory of Unitika Ltd. (56) References JP-A-49-48973 (JP, A) JP-A-2-289159 (JP, A) JP-A-5-5261 (JP, A) JP-A-5-125645 (JP, A) JP-A-5-263344 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) D04H 1/00-18/00

Claims (7)

(57) [Claims] An ethylene-propylene random copolymer component having an ethylene content of 1 to 10% by weight, and a melt flow rate 1.1 to 2.0 times the melt flow rate of the ethylene-propylene random copolymer component. 20 to 80% by weight of a composite type long fiber having a propylene polymer having a side-by-side or an eccentric sheath-core type and having crimp, and 80 to 20% by weight of a non-composite type long fiber consisting only of a polypropylene component. A stretchable long-fiber nonwoven fabric characterized by being uniformly mixed and having a point fusion zone in which long fibers are fused to each other by melting or softening of the ethylene-propylene random copolymer component. 2. The elongation recovery rate at 30% elongation is 20% both vertically and horizontally.
Above, and the compression stiffness is less than 80 g, the apparent density 0.1 g / cm ³ or less is claim 1 stretchable filament nonwoven fabric according. 3. The melt flow rate of the ethylene-propylene random copolymer component is from 10 to 100 g / 10 minutes,
Melt flow rate of propylene polymer is 20 to 120 g / 1
The stretchable long-fiber nonwoven fabric according to claim 1 or 2, wherein the time is 0 minutes. 4. An ethylene-propylene random copolymer component having an ethylene content of 1 to 10% by weight, and a melt flow rate 1.1 to 2.0 times the melt flow rate of the ethylene-propylene random copolymer component. Melt-spinning a conjugated long fiber obtained by compounding a propylene polymer having a side-by-side or eccentric sheath-core type with a propylene polymer, and melt-spinning a non-composite long fiber consisting only of a polypropylene component, and then the conjugated long fiber 20 to 80% by weight and the non-composite long fiber 80 to
20 wt% was simultaneously introduced into the air soccer and pulled, then both long fibers were discharged from the air soccer and opened, and then both the long fibers were deposited on a collecting conveyor to obtain a fiber web. Heat is applied to the spaced point areas of the fibrous web to melt or soften the ethylene-propylene random copolymer component to fuse between the long fibers to form a point fused area, and A method for producing a stretchable long-fiber nonwoven fabric, characterized in that a heat treatment is performed at the same time as the formation of the crimping section or after the formation of the point fusion section, so that the composite long fiber develops crimp. 5. The ethylene-propylene random copolymer component has a melt flow rate of 10 to 100 g / 10 minutes,
Melt flow rate of propylene polymer is 20 to 120 g / 1
The method for producing a stretchable long-fiber nonwoven fabric according to claim 4, wherein the time is 0 minutes. 6. The expansion and contraction roll according to claim 4, wherein an uneven roll heated to a temperature equal to or lower than the melting point of the ethylene-propylene random copolymer component is used to apply heat to the spaced point areas of the fibrous web. Method for producing non-woven long-fiber nonwoven fabric. 7. The method for producing a stretchable long-fiber nonwoven fabric according to claim 4, wherein ultrasonic waves are used to apply heat to the spaced point areas of the fibrous web.