JPH08260323A - Biodegradable filament nonwoven fabric and its production - Google Patents

Abstract

PURPOSE: To obtain the subject nonwoven fabric by mixing plural thermoplasticbiodegradable filaments having different heat shrinkable properties, thermally fusing the filaments at point contact bonding parts between single yarns, useful as a diaper, a sanitary article, etc. CONSTITUTION: Plural thermoplastic biodegradable filaments obtained from thermoplastic biodegradable polymers, having heat shrinkable properties are mixed and thermally fused at point contact bonding parts between single yarns to retain a shape. The filament having the smaller heat shrinkage percentage is deformed into a curved state in the thermal fusing to give the objective bulky nonwoven fabric. The plural filaments having different section states are preferably mixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a biodegradable long fiber nonwoven fabric and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a viscose rayon short fiber non-woven fabric obtained by a dry method or a solution dipping method, a cupra rayon long fiber non-woven fabric obtained by a wet spun bond method, a viscose rayon long fiber non-woven fabric, a natural material such as chitin or atelocollagen. Various biodegradable nonwoven fabrics such as a nonwoven fabric made of fibers and a spunlace nonwoven fabric made of cotton are known.

However, since these biodegradable nonwoven fabrics have low strength and hydrophilicity as a constituent material of the nonwoven fabric, the mechanical strength and elongation of the nonwoven fabric are remarkably lowered when absorbing water and getting wet. In addition, the shrinkage is large during repeated drying and wetting, resulting in poor dimensional stability. Also, the flexibility is poor. Further, since the material itself is non-thermoplastic, it has various problems such as not having thermal adhesiveness.

In order to solve the above problems, the present inventors have
As a long-fiber non-woven fabric using a thermoplastic biodegradable polymer, for example, the non-woven fabric described in JP-A-6-207323 and the non-woven fabric described in JP-A-6-207324 have been proposed. The products according to these proposals are useful non-woven fabrics because they are surely excellent in mechanical strength and dimensional stability and also excellent in heat adhesion.

[0005]

However, a nonwoven fabric having bulkiness is required depending on the development of applications, and a biodegradable long-fiber nonwoven fabric having improved bulkiness has been demanded.

The present invention aims to solve the above problems and provide a biodegradable long-fiber nonwoven fabric having improved bulkiness and a method for producing the same.

[0007]

Means and Action for Solving the Problems The present inventors have
The present invention has been achieved as a result of intensive studies to solve the above problems. That is, the present invention provides (1) at least two kinds of long fibers each made of a biodegradable polymer having thermoplasticity and different in heat shrinkage property from each other are mixed, and heat is applied at a point pressure bonding portion between single fibers. A biodegradable long-fiber non-woven fabric characterized by being fused and retained in shape, and (2) at least two biodegradable polymers each having thermoplasticity are individually melt-measured to form a spinneret. At least two kinds of fibers having different heat-shrinking properties were spun from the apparatus, the spun fibers were cooled, and then drawn by an air sucker, and the fibers were deposited on a moving conveyor net to form a fibrous web. Then, the gist is a method for producing a biodegradable long-fiber nonwoven fabric, which is characterized in that the fibrous web is thereafter subjected to point pressure bonding between an engraving roll and a flat roll.

As described above, according to the present invention, at least two kinds of long fibers having different heat shrinkage characteristics are mixed and the shape is maintained by heat fusion at the point pressure bonding portion between the single fibers. During heat fusion, one of the two types of long fibers undergoes heat contraction more than the other, and the other long fiber is deformed into a curved shape, whereby the obtained biodegradable long fibers are obtained. The fibrous nonwoven fabric becomes bulky.

Next, the present invention will be described in detail. As the thermoplastic biodegradable polymer, an aliphatic polyester polymer is suitable. Examples of the aliphatic polyester-based polymer include poly (α-hydroxy acid) such as polyglycolic acid and polylactic acid, or a copolymer of repeating unit elements constituting the poly (α-hydroxy acid). Further, poly (ω-hydroxyalkanoate) such as poly- (ε-caprolactone) and poly (β-propiolactone) can be mentioned. Further, poly-3-hydroxypropionate, poly-3-hydroxybutyrate, poly-3-hydroxycaprolate, poly-3-hydroxyheptanoate, poly-3-hydroxyoctanoate, and these and poly Mention may be made of poly (β-hydroxyalkanoates), such as copolymers with -3-hydroxyvalerate and poly-4-hydroxybutyrate. Moreover, the thing which consists of a condensation polymer of glycol and dicarboxylic acid is mentioned,
This includes, for example, polyethylene oxalate, polyethylene succinate, polyethylene adipate, polyethylene azelate, polybutylene oxalate, polybutylene succinate, polybutylene adipate, polybutylene sebacate, polyneopentyl oxalate or their copolyesters. An example is coalescence.

Further, the aliphatic polyester, polycapramide (nylon 6), polytetramethylene adipamide (nylon 46), polyhexamethylene adipamide (nylon 66), polyundecanamide (nylon 1).
1), even if an aliphatic polyesteramide-based polymer, which is a condensation polymer with an aliphatic polyamide such as polylaurolactamide (nylon 12), is used as long as it has biodegradability You can

The biodegradable polymer for forming at least two kinds of long fibers to be mixed with each other may be appropriately selected from the above polymers having different heat shrinkage characteristics. In the case of composite fibers, the melting point difference is 3 ° C or more and 15
A combination of 0 ° C. or lower is preferable because the low melting point component can contribute as a thermal bonding component and the other components can contribute as a fiber holding component. If the melting point difference is less than 3 ° C., it will be a combination of all fusion type fibers, resulting in lack of thermal adhesiveness, which is not preferable.

When at least two kinds of long fibers to be mixed are selected by a combination of fiber cross sections, they have different cross-section structures such as a round cross section, a modified cross section, a hollow cross section and a composite cross section, and have different heat shrinkage characteristics. The same kind or different kinds may be selected from the above. The composite cross section includes a core-sheath type, a parallel type, a multi-core type, a multi-layer type, various divided types, and the like.

When at least two kinds of long fibers to be mixed and having different heat shrinkage characteristics to be mixed are selected by a combination of their fineness, it is preferable that each fineness is selected from the range of 1 to 10 denier. When it is less than 1 denier, there are problems such as control of the solidification point when forming fibers, improvement of accuracy of die holes, and reduction of productivity due to reduction of discharge amount. If it exceeds 10 denier, flexibility is impaired, which is not preferable.

That is, in order to make the heat shrinkage characteristics of at least two kinds of long fibers to be mixed different, at least one of the above-mentioned fiber constituent polymer, fiber cross section and fineness may be made different. . Any two or all three may be different.

It is sufficient if at least two types of long fibers are mixed, but the number of types may be increased to three types and four types. When the long fibers are mixed, voids increase in areas other than the contact portions between the fibers, resulting in bulkiness and increased flexibility.

Next, specific examples of fibers constituting the nonwoven fabric of the present invention will be described. FIG. 1 is a diagram schematically showing an example of a cross section of the fiber. Here, (b) to (e) show typical examples of modified cross sections, and (f) to (g) show typical examples of hollow cross sections. (h) shows a typical example of a core-sheath type composite section, (i) shows a multi-core type composite section, and (J) shows a typical example of a parallel type composite section. (k) to (o) show typical examples of split-type composite sections and multilayer sections. It is to be noted that these may be combined with a modified hollow cross section, or the one component illustrated may be used as a multilayer component or a blend component.

In the above fibers, heat-resistant agents, light-resistant agents, weather-resistant agents, matting agents, plasticizers, pigments, dyes, surfactants, surface modifiers, various inorganic and organic electrolytes, fine powders, flame retardants, It may also contain an antioxidant and the like.

In the nonwoven fabric of the present invention, it is necessary that at least two kinds of mixed filament long fibers are fused at the point pressure-bonding portion between the single fibers to maintain the shape. The point crimping referred to here is a round shape, a slit shape, a cross shape, a ten-leaf shape, a triangular shape, a trilobal shape, a square shape, a pentagonal shape, a hexagonal shape, an octagonal shape, a four-leaf type, a five-leaf type, a hexalobe shape, Refers to the Yatsuha type, swastika type, etc. This point crimping is evaluated by the crimping area ratio in the non-woven fabric. This crimping area ratio is taken by magnifying an image with a scanning electron microscope using a small piece of non-woven fabric, and the point crimping is performed with respect to the area of the minimum repeating unit. The ratio of the sum of the areas of the parts was individually measured 10 times, and the average value was calculated.

The pressure-bonding area ratio of this nonwoven fabric is preferably 4 to 50%. If it is less than 4%, the flexibility of the non-woven fabric is improved, but the strength of the non-woven fabric is reduced, and fuzzing is likely to occur when the non-woven fabric is rubbed, which causes a problem in practical use. If the pressure-bonding area ratio exceeds 50%, the nonwoven fabric itself becomes extremely hard and the handling becomes poor. Therefore, it is more preferable that the pressure bonding area ratio is 5 to 40%. The non-woven fabric retains its shape by being fused at these point pressure-bonding portions, and since the other portions are not fused, the non-woven fabric is easy to bend and easy to handle.

In the present invention, the basis weight of the nonwoven fabric is not particularly limited. The non-woven fabric having a low basis weight can be applied to top sheets for sanitary materials, household drainage bags, book covers, filters, frost-proof sheets for agriculture, etc. Also, the high-density non-woven fabric can be applied to applications such as planting containers. Therefore, it can be applied to a wide range of applications regardless of the unit weight.

The nonwoven fabric of the present invention retains practical mechanical properties and is excellent in flexibility and especially bulkiness. The value indicating this flexibility is compression stiffness, and the smaller the value of this compression stiffness, the greater the flexibility.

The compression stiffness of the nonwoven fabric of the present invention is 0.2 to
0.4 g / g / m ² is preferred. Compression stiffness is 0.2g
If it is less than / g / m ² , the nonwoven fabric is too soft,
Problems such as lack of morphological stability and impaired web transfer during the production of a non-woven fabric, resulting in inability to produce with good operability, occur. On the other hand, compression stiffness is 0.4 g / g
If it exceeds / m ² , there are problems such as deterioration in flexibility and appearance of coarse and hard feeling. Therefore, the more preferable compression stiffness is 0.22 to 0.38 g / g / m ² , and the most preferable compression stiffness is 0.25 to 0.35 g / g / m.
²

The bulkiness depends on the bulk density, that is, the density of the nonwoven fabric.
The smaller the value, the higher the volume.
You The bulk density of the nonwoven fabric of the present invention is 0.05 to 0.2 g /
cm ³It is preferred that Bulk density is 0.05g / c
m³If less than, it is difficult to manufacture with thermocompression bonding type
It 0.2g / cm³If it exceeds, the bulkiness decreases
As a result, the intended bulky nonwoven fabric cannot be obtained. Accordingly
And more preferable bulk density is 0.06 to 0.17 g / cm.
³And the most preferable bulk density is 0.07 to 0.15.
g / cm³Is.

Next, a method for producing the biodegradable long fiber nonwoven fabric of the present invention will be described. However, it goes without saying that the method of the present invention is not limited to the specific method described below.

In order to produce the biodegradable long-fiber nonwoven fabric of the present invention, a spunbond method using a generally known melt composite spinning device can be applied. In order to produce the long fibers made of the above-mentioned thermoplastic biodegradable polymer, it is sufficient to select two or more appropriate ones from the above-mentioned polymers, but as described above, the melting point difference is 3 ° C. It is preferable that the combination is not less than 150 ° C. and not more than 150 ° C. Then, these biodegradable polymers are individually melted and weighed, and 2
At least one kind of fiber may be spun. 2 with this spinneret device
In order to spin out more than one kind of fiber, take a composite form in which individual components are different in the spinneret device, or take a mixed fiber form by co-spinning so that individual components can be spun individually. Etc. are required.

FIG. 2 shows a spinneret device for obtaining two types of mixed fiber as a specific example of the case where a mixed fiber form by co-spinning is adopted so that individual components can be spun independently in the spinneret device. 3 is a schematic view of a cross section. In FIG. 2, 1 is a distribution plate, 2 is a perforated plate, and 3 is a base plate. The individual polymers into which the two components A and B have been introduced from the side surface of the distribution plate 1 and which have been filtered by the perforated plate 2 are then passed through the individual guide holes 4 and 5 and spun from the spinneret holes 6 and 7. Will be issued. Mouth hole 6
The cross section of the spun fiber is, for example, a circular cross section if the spinneret hole is a round hole, and a modified cross section or a hollow cross section if slit holes are combined as the spinneret hole. By applying this also to the mouth hole 7, a mixed fiber of any combination can be obtained.

FIG. 3 schematically shows a cross section of a spinneret device for obtaining three kinds of mixed fiber as a specific example in the case of taking different composite forms in the spinneret device. In FIG. 3, 8 is a distribution plate, 9 is a perforated plate, and 10 is a base plate. The individual polymers into which the two components A and B have been introduced from the side surface of the distribution plate 8 and which have been filtered by the perforated plate 9 are introduced into the upper portion of the die plate 10 through the guide holes 11 to 16. The component A that has passed through the guide holes 11 and 16 is directly spun out from the mouth holes 21 and 24 through the guide holes 17 and 20 of the die plate 10. On the other hand, the A component that has passed through the guide hole 12 and the B component that has passed through the guide hole 13 merge near the upper portion of the guide hole 18 of the die plate 10, and are spun out from the die hole 22 as a parallel type composite flow.
Further, the A component passing through the guide hole 15 is a sheath component flow, and the B component passing through the guide hole 14 is a core component flow, both of which join together near the top of the guide hole 19 of the die plate 10 to form a core-sheath composite flow. After passing through the guide hole 19, it is spun from the spinneret hole 23. In addition, in FIG.
If it is made into a slit-shaped hole and the spinneret hole 23 is spun out into a round hole, a fiber cross section corresponding to FIG. 1 (j) can be obtained from the spinneret hole 22 and a fiber from the spinneret hole 23 to the FIG. Corresponding fiber cross sections can be obtained, and further, three kinds of fibers consisting of a single component of component A from the die holes 21 and 24 can be obtained as a mixed fiber at the same time. That is, if the die hole is formed into a slit of −, Y, +, * shape or the like, an irregular cross section is obtained, and if a combination of C shape, Y shape, etc. is formed, a hollow cross section is obtained.

In the case of a fiber having a multi-layer structure, an arbitrary cross section can be obtained by passing through a static mixer in the spinneret pack or in a step before that. As a static mixer for that purpose, "Thruzer mixer" of Sruzer Co., "Static mixer" of Kenix Co., "High mixer" of Toray Co., etc., Raschig ring, Morundum, filter media such as a laminate of wire mesh, and these A combination of can be applied. The number of stages of the kneading elements of the static mixer cannot be determined unconditionally because each pressure loss varies depending on the type,
16 is preferable. If the number of kneading elements is too large, the blending type may be mere blended type, and only unnatural ones may be obtained.

There is no problem in measuring each component because they are individually melt-measured. Further, as a measuring means for further distributing one component into a composite component or a single component, for example, when the diameters of the guide holes of the perforated plate 9 in FIG. 3 are the same, the number of guide holes is controlled. The distribution ratio can be changed. Furthermore, when the number of guide holes is the same, the distribution ratio can be changed by changing the hole diameter of the guide holes.

Then, two or more kinds of fibers are spun by the above spinneret device, cooled, and then pulled by an air sucker,
If necessary, the fibers are opened by an opening device, and the fibers are deposited on a moving conveyor net to form a fiber web.

Here, it is important to spin and cool two or more kinds of fibers together with towing with an air sucker. That is, since different fibers are spun out, the solidification points of the single fibers themselves are different, which affects the spinnability.

In order to produce co-spun fibers with good operability, it is particularly necessary to adjust the solidification point of the single fiber itself, and the difference in the solidification point of the single fiber itself (the difference between the solidification points of different fibers It is important to make the maximum difference) as small as possible. Here, the solidification point difference means the difference between the minimum distance and the maximum distance when the distance from the spinneret surface to the point where the fiber is cooled and solidified is measured for each fiber. On the other hand, when the fiber is pulled by an air sucker, the air in the atmosphere is also sucked, so that a very subtle breathing phenomenon appears in the air sucker. This phenomenon may also lead to a change in the solidification point of the spun monofilaments.

Therefore, it is necessary to reduce the difference in solidification point of the single fiber, but in the method of the present invention, the fiber yarn is
Since the components, the fineness, and the cross-sectional shape are individually different, it is preferable that the difference in the solidification point of the fibers of different types is 50 cm or less for simultaneous spinning. This solidification point difference is 5
If it exceeds 0 cm, yarn breakage may occur, which may be a defect of the nonwoven fabric, or adhesion between single fibers may occur, resulting in deterioration of the texture of the nonwoven fabric, which is not preferable.

Traction of fiber yarn by air soccer
It is desirable to make the spinning speed as high as possible within the range where yarn breakage does not occur. The reason is that the orientation of the fibers is increased, the heat shrinkability is suppressed, and the physical properties of the non-woven fabric are improved. That is, the high spinning speed is preferable also from the viewpoint of productivity, and the degree of crystal orientation of the fiber is increased. In addition, since the heat shrinking property is lowered by setting the high spinning speed, the heat resistance and the dimensional stability are naturally improved. Further, since the strength of the fiber itself is maintained, the strength of the non-woven fabric is also increased.

Next, the opened fiber web is point-pressed by an embossing machine and the product is wound by a winding machine, whereby a desired nonwoven fabric can be manufactured. As the embossing method for maintaining the shape of the non-woven fabric by the point pressure bonding, a known hot embossing machine or ultrasonic welding machine currently used for dry non-woven fabric can be applied.

When a hot embossing machine is applied, the processing temperature is generally 5 ° C. lower than the melting point of the polymer component having the highest melting point among the polymers used, and Can be applied up to a temperature of 50 ° C below the melting point of the polymer component having the lowest melting point. If a temperature exceeding 5 ° C. lower than the melting point of this high melting point component is applied,
The texture of the non-woven fabric becomes hard, the handling is poor, and the non-woven fabric has low tear strength. If the processing temperature is further higher than this, the fibrous web is taken by the engraving roll or the metal smooth roll, and it becomes impossible to produce a nonwoven fabric with good operability. On the other hand, when the temperature is lower than the melting point of the low-melting point component by 50 ° C., the fibrous web is not thermocompression bonded, and the shape retention of the nonwoven fabric is deteriorated. If the processing temperature is lower than this, the fibrous web will be picked up by the engraving roll, and it will not be possible to produce a nonwoven fabric with good operability. The reason why thermocompression bonding can be performed even if the processing temperature is lower than the melting point of the low melting point component is that the softening point of the low melting point component is within the processing temperature range and pressure is applied at the pressure bonding point part of the engraving roll. This is because of the state of being fused.

In manufacturing a nonwoven fabric, the pattern formed by point pressure bonding is important because it affects the strength, flexibility and texture of the nonwoven fabric, and the engraving area and shape of this engraving roll is one of the points. . The standard of the engraving area can be indicated by the crimping area ratio when thermocompression-bonding, and the crimping area ratio for obtaining the nonwoven fabric of the present invention is 4 to 5 as described above.
0% is preferable.

On the other hand, in the case of an ultrasonic welding machine, the web may be passed between the engraving roll and a support having an ultrasonic welding mechanism to oscillate an ultrasonic wave of about 20 kHz. When changing the welding state, the wavelength of the ultrasonic wave may be changed appropriately depending on the material used. The linear pressure in this case is 0.5 to 2 kg / c, unlike the heat embossing machine.
About m may be used. Moreover, the crimping area ratio is 4 to 50%.
Is preferred.

This non-woven fabric subjected to point pressure bonding by ultrasonic welding is more preferable because fibers other than the point pressure bonding part are hardly affected by heat and the texture does not become hard.

[0040]

EXAMPLES Next, the present invention will be specifically described based on Examples. In addition, measurement and evaluation of various characteristics in the following examples were performed by the following methods.

Melting point Tc (° C.) of the polymer: the temperature which gives the extreme value of the melting absorption curve measured by using a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. at a heating rate of 20 ° C./min. The melting point (° C) was used.

Crystallization temperature Tm of the polymer: a temperature which gives the maximum value of the solidification exothermic curve obtained by measuring with a differential scanning calorimeter DSC-2 type manufactured by Perkin Elma Co., Ltd. at a heating rate of 20 ° C./min. Was the crystallization temperature (° C).

Melt viscosity (g / 10 minutes): ASTM-D
It measured at the temperature of 190 degreeC according to the method as described in -1238 (E). In the following, this is referred to as "MFR value".

Fiber-spreading property of spun yarn: The nonwoven fabric formed from the web discharged from the fiber-spreading device was visually evaluated according to the following three grades. ◯: Most of the constituent fibers are opened, and no adherent yarn or convergent yarn is observed.

Δ: Adhesive yarn and convergent yarn are recognized in a very small part of the constituent fibers. X: Most of the constituent fibers are in close contact with each other and the openability is poor.・ Unit weight (g / m ² ): 10 cm in length from the standard state sample
Ten pieces of 10 cm wide sample pieces were prepared and equilibrated with water. Then, the weight of each sample piece was weighed, and the average value of the obtained values was converted per unit area to obtain a basis weight (g / m ² ). did.

Tensile strength (kg / 5 cm) and tensile elongation (%) of the non-woven fabric: JIS L-1096 using a constant-speed extension type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.) In accordance with the strip method described in 1., 10 sample pieces having a sample width of 5 cm and a sample length of 20 cm were prepared and measured at a gripping interval of 10 cm and a pulling speed of 10 cm / min. The maximum tensile strength of each individual in that case was averaged to obtain the tensile strength. Further, the elongation corresponding to the maximum strength at that time was averaged to obtain the tensile elongation (%) of the nonwoven fabric.

Thickness (mm): A thickness measuring machine (manufactured by Daiei Kagaku Seiki Seisakusho) was used to measure the thickness (mm) after 10 seconds under an applied load of 4.5 g / cm ² . -Bulk density (g / cm ³ ): Calculated from the above basis weight and thickness by the following formula to obtain the bulk density (g / cm ³ ).

Bulk density (g / cm ³ ) = basis weight / thickness / 1000-Compression stiffness (g / g / m ² ): sample width in the machine direction of the nonwoven fabric is 5 cm, sample length in the direction orthogonal to this direction Is 10
Five sample pieces of cm were prepared, each sample piece was bent in the lateral direction to form a cylindrical shape, and the ends thereof were joined to each other to obtain a measurement sample. Then, each measurement sample was compressed in the axial direction, that is, the width direction of the sample at a compression rate of 5 cm / min using a constant-speed extension type tensile tester (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.) to obtain The average value of the maximum load values (g) thus obtained was divided by the above basis weight to obtain the compression stiffness (g / g / m ² ).

Biodegradability: When a non-woven fabric sample piece is embedded in soil and taken out after 6 months, the non-woven fabric form is not retained, or when the non-woven fabric form is retained, the tensile strength is 50% of that before embedding. The case where it was decreased below was evaluated as good degradability. (Example 1) As the first component, the MFR value was 40 g / 1.
A polybutylene succinate resin having a melting point Tm of 114 ° C. and a crystallization temperature Tc of 75 ° C. is used for 0 minutes, and the second component has an MFR value of 30 g / 10 minutes and a melting point Tm of 102.
C., a crystallization temperature Tc of 52.degree. C., a polybutylene succinate / polyethylene succinate = 85/15 mol% copolymer resin is used, melt spinning is performed, and a nonwoven fabric composed of two kinds of mixed filaments is obtained. Manufactured.

That is, these first and second components are
A spinneret device as shown in FIG. 2 is used to melt the fibers at a temperature of 180 ° C. by using an individual extruder-type melt-extruder to form a mixed fiber of the cross-sections of (a) and (b) of FIG. Was melt-spun. At this time, the single hole discharge rate is 1.3 g /
And the discharge ratio of the first component and the second component is 1/1
As the (weight ratio), mixed filament long fibers were melt-spun.

Next, these spun yarns were cooled by a cooling device, and using an air sucker installed below the spinneret,
The fiber web was collected at a drawing speed of 3500 m / min, and then opened by a known opening device to deposit the fiber web on the moving screen conveyor. This fibrous web has a single-filament fineness of the first component and a single-filament fineness of the second component both of about 3.3 denier, and is the same as the fiber of the cross section of FIG. 1 (a).
It was composed of a long fiber group having a fiber mixture ratio of the cross section of (b) = 1/1 (weight ratio). Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . At the time of thermocompression bonding, the shape of the pressure bonding portion is round, the area is 0.68 mm ² , the engraving pattern is arranged, and the density of the pressure bonding points is 16 pieces / cm ² , and the surface of the metal is smooth. The thermocompression bonding temperature was set to 95 ° C. using an embossing machine consisting of rolls.

Table 1 shows the spinning operability at that time and the physical properties and biodegradability of the obtained nonwoven fabric.

[0053]

[Table 1]

(Example 2) A spinneret device using the same first and second components as in Example 1 to obtain a mixed fiber of the cross sections of (h) and (j) of FIG. Using a spinning temperature of 18
Under the conditions of 0 ° C., single hole discharge rate of 0.8 g / min, and discharge ratio of the first component and the second component = 1/1 (weight ratio), the mixed fiber composite long fibers are melt-spun. I put it out. Next, these spun yarns are cooled by a cooling device, and with an air sucker installed below the spinneret, a pulling speed of 3300 m / min is taken up, and thereafter the fibers are opened by a known opening device. On the moving screen conveyor, the single yarn fineness of the fiber corresponding to the cross section of (h) and the single yarn fineness of the fiber corresponding to the cross section of (j) are both about 2.2 denier, and (h ) And the fiber corresponding to the cross section of (j) have a mixed fiber ratio of 1/1
A fibrous web of long fiber groups (weight ratio) was deposited. In this fibrous web, the second component is the sheath component and the fiber of the cross-section in Fig. 1 (h) and the second component is the convex portion.
It was composed of a long fiber group having a mixed fiber ratio of 1/1 (weight ratio) with the fiber of the cross section of (j). Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The thermocompression bonding conditions were the same as in Example 1. (Example 3) Using the same first and second components as in Example 1, a spinneret device was used in which the fibers of the cross sections of (k) and (d) in Fig. 1 were mixed. Then, the single hole discharge rate from the die hole corresponding to the cross section of FIG.
The first component is configured to form an outer peripheral 6-divided convex portion, and the ejection ratio of the first component and the second component at that time = 1/1.
(Weight ratio). In addition, the first component is discharged from the die hole corresponding to the cross section of FIG.
The mixed filament type composite filament was melt-spun at a rate of g / min. These spun yarns are cooled by a cooling device, and the pulling speed is 3500 m using an air sucker installed below the spinneret.
/ Minute, and then opened with a known opening device. Furthermore, on the moving screen conveyor,
The single yarn fineness of the fiber corresponding to the cross section of (k) and the single yarn fineness of the fiber corresponding to the cross section of (d) are both about 3.3 denier, and the fiber corresponding to the cross section of (k) A fiber web composed of long fiber groups having a mixed fiber ratio with fibers corresponding to the cross section of (d) of 1/1 (weight ratio) was deposited. Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The thermocompression bonding conditions were the same as in Example 1. (Example 4) The fiber web obtained in Example 1 was used for point bonding processing by an ultrasonic heat welding machine. The point of the engraving roll is round, and its area is
The pressure-bonding point density was 0.6 mm ² , the pressure-bonding point density was 20 pieces / cm ² , and the pressure-bonding area ratio was 15%. The frequency was 19.2 kHz. (Example 5) Using the same first and second components as in Example 1, a mixed fiber of three types of fibers having the cross sections of (d), (k), and (j) of FIG. 1 is obtained. A spinneret device was used. Then, the single hole discharge amount from the die hole corresponding to the cross section of FIG.
8 g / min, and the single hole discharge rate from the die hole corresponding to the cross sections of (k) and (j) in the same figure was 1.2 g / min, and the first and second components at that time were set. Discharge ratio = 1
The mixed filament type composite long fiber was melt-spun at a ratio of 1/1 (weight ratio). The arrangement of each component in each cross section was the same as in Examples 2 and 3. Next, these spun yarns were cooled by a cooling device, and were pulled at a pulling speed of 3300 m / min using an air sucker installed below the spinneret, and then opened by a known opening device. . Furthermore, on the moving screen conveyor, the single yarn fineness of the fiber corresponding to the cross section of (d) is 2.2 denier, and the single yarn fineness of the fiber corresponding to the cross sections of (k) and (j) are both about 3.3 denier,
A fiber web consisting of long fiber groups having a mixed fiber ratio of the fibers of the section (d), the fibers of the section (k) and the fibers of the section (j) = 1/1/1 was deposited. Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The thermocompression bonding conditions were the same as in Example 1. (Example 6) The same first component as in Example 1 was used. As the second component, polybutylene succinate / polybutylene adipate = 80/2 having an MFR value of 25 g / 10 minutes, a melting point Tm of 94 ° C. and a crystallization temperature Tc of 48 ° C.
0 mol% of copolymer resin was used. In addition, (h) in Fig. 1
The spinneret device was used so that the fibers of the cross section with (j) were mixed, and the arrangement of the components in each cross section was the same as in Example 2. Then, the spinning temperature is 180 ° C., the single hole discharge amount is 1.5.
g / min, discharge ratio of first component and second component = 1/1
As the (weight ratio), mixed fiber type composite long fibers were melt-spun. Next, these spun yarns were cooled by a cooling device, and were pulled at a pulling speed of 3800 m / min using an air sucker installed below the spinneret, and then opened by a known opening device. . Furthermore, on the moving screen conveyor, the single yarn fineness of the fiber corresponding to the cross section of (h) and the single yarn fineness of the fiber corresponding to the cross section of (j) are both about 3.6 denier, and (h) A fiber web composed of long fiber groups having a mixed fiber ratio of the fibers of the cross section of (1) and the fibers of the cross section of (j) = 1/1 (weight ratio) was deposited. Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The thermocompression bonding conditions were the same as in Example 1 except that the thermocompression bonding temperature was 87 ° C.

Also in these Examples 2 to 6, the spinning operation was performed.
Table 1 shows the properties and the physical properties and biodegradability of the obtained nonwoven fabric.
Shown in. (Comparative Example 1) Using only the first component in Example 1,
In addition, the thread cross section becomes a normal round shape, that is, the cross section of (a) in Fig. 1.
Using a spinning spinneret such as
Long fibers were melt spun at a hole discharge rate of 1.5 g / min. next,
This spun yarn is cooled by a cooling device and installed below the spinneret.
Using air sucker, pulling speed is 3900m /
After collecting it as a minute, open it with a known opening device,
In addition, on the moving screen conveyor, the single yarn fineness is
A fibrous web consisting of filaments of about 3.5 denier
Stacked vertically. Then, the fiber web is thermocompressed and
With 30g / m ²A biodegradable long-fiber non-woven fabric was obtained. Heat pressure
The bonding conditions were those of Example 1 except that the thermocompression bonding temperature was 107 ° C.
Same as. (Comparative Example 2) Using only the second component in Example 1,
In addition, the thread cross section becomes a normal round shape, that is, the cross section of (a) in Fig. 1.
Using a spinning spinneret such as
Long fibers were melt-spun at a hole discharge rate of 1.2 g / min. next,
This spun yarn is cooled by a cooling device and installed below the spinneret.
Using the air sucker, pulling speed of 3600m /
After collecting it as a minute, open it with a known opening device,
In addition, on the moving screen conveyor, the single yarn fineness is
A fibrous web consisting of filaments of about 3.0 denier
Deposited. Then, the fiber web is thermocompressed and
With 30g / m ²A biodegradable long-fiber non-woven fabric was obtained. Heat pressure
The bonding conditions were the same as in Example 1 except that the thermocompression bonding temperature was 87 ° C.
I did the same. (Comparative Example 3) MFR value is 25 g / 10 minutes, melting point Tm is 8
Polybutylene succine with 4 ° C and crystallization temperature Tc of 22 ° C
% / Polyethylene succinate = 60/40 mol%
Only the copolymer resin was used. Also, the thread cross section is an ordinary hollow circle.
Spinneret having a shape, that is, the cross section of Fig. 1 (f)
The spinning temperature is 160 ° C and the single hole discharge rate is 1.2 g / min.
Then, a long fiber having only a hollow cross section was melt-spun. Next
Then, cool this spun yarn with a cooling device and place it below the spinneret.
With installed air soccer, pulling speed is 3500
After taking it up as m / min, open it with a known opening device
Then, on the moving screen conveyor, the single yarn
A fiber c consisting of a long fiber group having a fineness of about 3.1 denier
Web was deposited. Then, heat bond this fiber web.
The basis weight is 30 g / m²To obtain biodegradable long-fiber nonwoven fabric
Was. The thermocompression bonding conditions are actual except that the thermocompression bonding temperature is 70 ° C.
Same as Example 1.

Also in these Comparative Examples 1 to 3, the spinning operability and the physical properties and biodegradability of the obtained nonwoven fabric are shown in Table 1.
Shown in As is clear from Table 1, in Example 1, it is possible to obtain a nonwoven fabric in which a single round fiber having no composite structure and a single trilobal fiber having a high heat shrinkability are mixed. It was The difference in the solidification points of both fibers was 10 cm, and there were no problems in cooling and opening properties, and the operation was good. The obtained non-woven fabric has practical strength, and since the irregularly shaped fibers are mixed, there are many voids between the fibers, which results in bulkiness,
It was excellent in flexibility and biodegradable.

In Example 2, the core-sheath type composite fiber,
It was possible to obtain a non-woven fabric in which three-leaf type parallel-type composite fibers were mixed. The difference in solidification point of both fibers is 15 cm,
There was no problem in cooling and opening properties, and the operation was good.
The obtained non-woven fabric has practical strength, and due to the heat of the thermocompression bonding device, the parallel type fibers have crimps of about 3 pieces / 25 mm, and the deformed fibers are mixed. As a result, there were many voids between the fibers, and the bulkiness and flexibility were excellent. It also had biodegradability.

In Example 3, it was possible to obtain a non-woven fabric in which protrusion type splitting type conjugate fibers and cross type single type irregularly shaped fibers were mixed. The difference between the solidification points of both fibers is 17
It was cm, and there was no problem in the cooling property and the fiber-opening property, and the operation was good. The obtained non-woven fabric was not only excellent in practical strength but also had a large number of voids between the fibers because the irregularly shaped fibers were mixed, and thus the bulkiness was further excellent and the flexibility was excellent. Moreover, it was biodegradable.

In Example 4, since the ultrasonic device was applied as the thermocompression bonding device, the fibers other than the pressure bonding portion are highly effective in being unaffected by heat, and the deformed fibers are mixed without being thermally deformed. Therefore, there were many voids between the fibers, which made the nonwoven fabric more excellent in bulkiness and flexibility. Further, it had a practically strong nonwoven fabric and also had biodegradability.

In Example 5, it is possible to obtain a non-woven fabric in which three kinds of protrusion type split type conjugate fiber, cross type single type irregularly shaped fiber, and trilobal type parallel type conjugate fiber are mixed. did it. The difference in the solidification point of the fibers during spinning was 38 cm, but there were no problems in cooling and opening properties, and the operation was good. The obtained non-woven fabric has practical strength and is mixed with three types of irregularly shaped fibers, and due to the heat of the thermocompression bonding device, the parallel type fibers are crimped by about 3 pieces / 25 mm. Since it was expressed, there were more voids between the fibers, and therefore, bulkiness and flexibility were further excellent. It also had biodegradability.

In Example 6, it was possible to obtain a non-woven fabric in which the core-sheath type composite fiber and the trilobal type parallel type composite fiber were mixed. Since the second component used had a somewhat lower melting point than in Example 2, the difference in the solidification points of the fibers during spinning was 2
Although it was as large as 0 cm, there was no problem in cooling and opening properties, and the operation was good. The obtained non-woven fabric has practically strong strength, is mixed with irregularly shaped fibers, and due to the heat of the thermocompression bonding device, the number of parallel type fibers is 8/25.
Since the crimp of about mm was developed, there were many voids between the fibers, and thus the nonwoven fabric was excellent in bulkiness and flexibility. It also had biodegradability.

As described above, in each of Examples 1 to 6, there is no problem in the cooling property and the fiber-opening property, and the operation is good. It was possible to obtain a non-woven fabric that was flexible and was particularly bulky. In particular, as is clear from Example 5, a nonwoven fabric composed of three types of mixed fibers was able to obtain a bulkier and softer nonwoven fabric than two types of mixed fibers. In Comparative Example 1,
Since the non-woven fabric is composed of a single fiber, there are problems in flexibility and bulkiness. In Comparative Example 2 as well, since the nonwoven fabric is composed of a single fiber similarly, there is a problem in flexibility and bulkiness. Further, a part of the filaments adhered to each other and the openability was lowered. In Comparative Example 3, since a polymer having a low crystallization temperature Tc was applied, most of the filaments adhered to each other and the openability was deteriorated, so that a sheet having a uniform texture could not be collected. (Example 7) The nonwoven fabric obtained in Example 2 was subjected to a relaxation heat treatment at a temperature of 70 ° C for 1 minute using a hot air circulation dryer. Then, in the parallel type fibers in the nonwoven fabric, 20/2
A crimp of 5 mm or more was developed. The nonwoven fabric performance is shown in Table 2. As is clear from Table 2, the nonwoven fabric was more bulky and excellent in flexibility due to the effect of the large number of crimps developed in the side-by-side composite fibers.

[0063]

[Table 2]

Example 8 As the first component, MFR value was 30 g / 10 minutes, melting point Tm was 108 ° C., crystallization temperature T
c is 59 ° C., a polybutylene succinate / polyethylene succinate = 90/10 mol% copolymer resin is used, and the second component has an MFR value of 46 g / 10.
Minutes, melt-spinning was performed using a poly- (ε-caprolactone) resin having a melting point Tm of 63 ° C. and a crystallization temperature Tc of 23 ° C. to produce a nonwoven fabric composed of two kinds of mixed filaments.

That is, these first and second components are
Example 3 was carried out using a spinneret device that melts at a temperature of 160 ° C. using a separate extruder-type melt-extruder to form a mixed fiber of the cross-sections of (k) and (d) of FIG. A fibrous web of long fibers was deposited in the same manner as in. Then, the fibrous web is thermocompression-bonded to have a basis weight of 30 g / m.
To obtain a ^second biodegradable filament nonwoven fabric. The thermocompression bonding conditions were the same as in Example 3 except that the temperature was 55 ° C. The results and the physical properties and biodegradability of the nonwoven fabric are shown in Table 2.

As is clear from Table 2, although poly- (ε-caprolactone) resin was used unlike Example 3, the difference in solidification point was slightly large, but the cooling property and the opening property were not changed, and The bulkiness and flexibility are improved, and the biodegradability is also improved. (Embodiment 9) The single-hole discharge rate from the die hole corresponding to the cross section of FIG. 1 (k) in Example 8 was set to 2.5 g / min, and the discharge ratio of the first component and the second component at that time was set. = 1.5 / 1 (weight ratio). Here, the first component is configured to form an outer peripheral 6-divided convex portion. In addition, the second component is discharged from the die hole corresponding to the cross section of Fig. 4 (d), and the single hole discharge rate is 0.8g.
The mixed filament type composite long fiber was melt-spun. These spun yarns are cooled by a cooling device, and an air sucker installed below the spinneret is used to pull at a speed of 3500 m / m.
It was taken out as a portion and then opened by a known opening device. Furthermore, the single yarn fineness of the fiber corresponding to the cross section of (k)
The single yarn fineness of the fiber corresponding to the cross section of (d) is 6.
A fiber web consisting of long fiber groups having a denier of 4 and 2.1 and a mixed fiber ratio of fibers corresponding to (k) and fibers corresponding to (d) is 1/1 (weight ratio). Were deposited on a moving screen conveyor. Then, the fibrous web was thermocompression-bonded to obtain a biodegradable long-fiber nonwoven fabric having a basis weight of 30 g / m ² . The thermocompression bonding conditions were the same as in Example 8. As a result, the physical properties and biodegradability of the nonwoven fabric are
It shows in Table 2.

As is clear from Table 2, a bulky nonwoven fabric was obtained because the constituent fibers have a wider range of fineness than that of Example 8. (Example 10) As the first component, the MFR value was 30 g /
10 minutes, melting point Tm is 102 ° C, crystallization temperature Tc is 52 ° C
As the second component, the polyethylene succinate resin of MFR value of 46 g / 10 min, melting point Tm of 63 ° C.,
A poly- (ε-caprolactone) resin having a crystallization temperature Tc of 23 ° C. was used. Then, melt spinning and making into a non-woven fabric were carried out under the same conditions as in Example 9 except that the spinning temperature was 155 ° C. to produce a non-woven fabric composed of two kinds of mixed filament long fibers. The results and the physical properties and biodegradability of the nonwoven fabric are shown in Table 2.

As is clear from Table 2, as a result of using the polyethylene succinate resin, a softer nonwoven fabric than that of Example 9 was obtained.

[0069]

According to the present invention, at least two kinds of long fibers, which are made of a biodegradable polymer having thermoplasticity and have different heat shrinkage characteristics from each other, are mixed, and the point pressure bonding portion between the single fibers is mixed. Since it is heat-fused and held in shape, it is possible to cause one of the two types of long fibers to shrink more than the other when heat-sealing, and the other long fiber is curved. The resulting biodegradable long-fiber nonwoven fabric can be made bulky. For this reason,
Practical non-woven fabric It is possible to obtain extremely bulky non-woven fabric with strong strength. This non-woven fabric is used for sanitary materials such as diapers and sanitary products, disposable squeezing cloth, wiping cloth,
It is suitable as a material for daily life such as a base cloth of a pap material, a dust collection bag for home or business use, and other waste treatment materials. Moreover, this non-woven fabric is useful from the viewpoint of protection of the natural environment, or is composted, for example, since it eventually decomposes and disappears completely when left in an environment where many microorganisms are present, such as soil or water, after use. Since it can be reused as fertilizer, it is useful from the viewpoint of resource reuse.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of fibers constituting a nonwoven fabric of the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of a spinneret device for producing the nonwoven fabric of the present invention.

FIG. 3 is a cross-sectional view schematically showing another example of the spinneret device for producing the nonwoven fabric of the present invention.

[Explanation of symbols]

 6 Mouth hole 7 Mouth hole 21 Mouth hole 22 Mouth hole 23 Mouth hole 24 Mouth hole A component B component

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[Procedure amendment]

[Submission date] May 15, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

Fiber-spreading property of spun yarn: The nonwoven fabric formed from the web discharged from the fiber-spreading device was visually evaluated according to the following three grades. ◯: Most of the constituent fibers are opened, and no adherent yarn or convergent yarn is observed. Δ: Adhesive yarn and convergent yarn are recognized in a very small part of the constituent fibers. X: Most of the constituent fibers are in close contact with each other and the openability is poor.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

-Basis weight (g / m ² ): 10 pieces of 10 cm long × 10 cm wide sample piece prepared from the standard state sample were prepared, equilibrated with water, and then the weight of each sample piece was weighed to obtain the obtained value. The average value of is converted per unit area and the basis weight (g / m ² )
And

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

Thickness (mm): A thickness measuring machine (manufactured by Daiei Kagaku Seiki Seisakusho) was used to measure the thickness (mm) after 10 seconds under an applied load of 4.5 g / cm ² . -Bulk density (g / cm ³ ): Calculated from the above basis weight and thickness by the following formula to obtain the bulk density (g / cm ³ ). Bulk density (g / cm ³ ) = basis weight / thickness / 1000

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0048

[Correction method] Change

[Correction content]

Compression stiffness (g / g / m ² ): 5 pieces of sample width of the nonwoven fabric in the machine direction of 5 cm and sample length of 10 cm in the direction orthogonal to this direction were prepared, and each sample piece was prepared. It was bent laterally into a cylindrical shape, and the ends thereof were joined together to obtain a measurement sample. Then, a constant speed extension type tensile tester (Tensilon UTM-4-1-10 manufactured by Toyo Baldwin Co., Ltd.
0) was used to compress each measurement sample in the axial direction, that is, the width direction of the sample at a compression rate of 5 cm / min, and the average value of the maximum load values (g) obtained was divided by the above basis weight to obtain the compression stiffness. (G / g
/ M ² ).

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Claims (9)

[Claims] 1. At least two kinds of long fibers each made of a biodegradable polymer having thermoplasticity and having different heat shrinkage properties are mixed, and heat fused at a point pressure bonding portion between single fibers. A biodegradable long-fiber non-woven fabric characterized by being retained in shape. 2. The biodegradable long-fiber nonwoven fabric according to claim 1, wherein the biodegradable polymer having thermoplasticity is an aliphatic polyester. 3. The biodegradable long-fiber nonwoven fabric according to claim 2, wherein the aliphatic polyester is made of polybutylene succinate or a copolymer containing polybutylene succinate as a main component. 4. The biodegradable long fiber nonwoven fabric according to claim 1, wherein at least two kinds of long fibers are composed of polymers different from each other. 5. The biodegradable long-fiber nonwoven fabric according to claim 1, wherein at least two kinds of long fibers are composed of fibers having different cross-sectional states. 6. The biodegradable long-fiber nonwoven fabric according to claim 1, wherein at least two kinds of long fibers are composed of fibers having different fineness. 7. A bulk density of 0.05 to 0.2 g / cm ^{3 according} to any one of claims 1 to 6.
The biodegradable long-fiber non-woven fabric according to the item. 8. At least two types of biodegradable polymers each having thermoplasticity are individually melt-measured, and at least two types of fibers having different heat-shrinking properties are spun out from a spinneret device. After cooling the discharged fiber, draw it with an air sucker, further deposit this fiber on a moving conveyor net to form a fiber web, and then press-bond this fiber web between an engraving roll and a flat roll. A method for producing a biodegradable long-fiber non-woven fabric, comprising: 9. The method for producing a biodegradable long-fiber nonwoven fabric according to claim 8, wherein the fiber web is formed such that the difference in solidification point between the spun fibers is 50 cm or less.