JP2871888B2 - 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 nonwoven fabric having a good texture, good touch, excellent drapability, texture, air permeability and strength, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, nonwoven fabrics have been widely used in many fields instead of woven fabrics. Because of its low cost and high productivity, it can be used as a substitute for a conventional woven fabric, or can be used as a functional nonwoven fabric because it can impart performance that cannot be obtained with a woven fabric. Further, conventionally, the use of nonwoven fabrics in the field of paper pulp as a raw material has been actively utilized as a high-performance material by utilizing the functionality of the nonwoven fabric.

Typical methods for forming a nonwoven web include a spunbond method, a melt-blow method, a dry method, and a wet method.

[0004]

However, individual methods cannot cover all fields.

[0005] Nonwoven fabrics obtained by the spunbonding method have high strength such as tensile strength and are widely used as industrial materials requiring high strength. However, since the method of joining the webs is mainly by thermocompression bonding, there is a drawback that the web is dense, the sheet is hard, and the drapability is poor.

[0006] Further, the nonwoven fabric produced by the melt blow method can produce an ultrafine fiber sheet, but has poor formation, is low in productivity, and is expensive.

[0007] The web formed by the card method or the air lay method by the dry method has a bulk and a feeling as compared with those obtained by the above method. However, for the purpose of imparting sheet strength, a binder is applied or heat is applied. When crimping is performed, bulkiness,
The texture decreases. Further, the card method cannot be applied to fibers having a diameter of 7 μm or less. In the air lay method, it is difficult to disperse long fibers exceeding 6 mm.

[0008] Nonwoven fabrics and special public sho 4 by the needle punch method
As disclosed in JP-A-8-13749, a spunlaced nonwoven fabric obtained by entanglement of a web formed by a card with a columnar water stream can be formed into a sheet with no binder, has a good texture, and has excellent drape properties. I have.

[0009] However, the web obtained by the above method has a problem that the formation is generally worse than that of the wet papermaking method.

On the other hand, the web obtained by the wet papermaking method has higher productivity, can use fibers having a small fiber diameter, can mix a plurality of fibers at an arbitrary ratio, and has a very good formation. There is an advantage that there is. However, in the usual method, the fiber length is required to be evenly dispersed in water and a uniform sheet is required, so that the strength is weak and the application is limited.

Conversely, if the fiber length is increased, the fibers are entangled and tied, making uniform dispersion difficult.

[0012] Further, since the drying method after paper-making is press-bonded to a Yankee or multi-cylinder dryer, or even when a through-type dryer is used, since the fibers are two-dimensionally oriented, paper-like There is also a problem that the air permeability and the drape property are inferior, and the one using the ultrafine fibers has a high density and the air permeability is poor.

In the method disclosed in Japanese Patent Application Laid-Open No. 2-6651, a short fiber web having a fiber diameter of 7 to 25 μm and a ratio (L / D) of a fiber length (L) to a fiber diameter (D) of 800 to 2000 is used. Is disclosed. The wet nonwoven fabric is obtained by three-dimensionally entangled with a high-pressure columnar water flow.

This non-woven fabric has attracted attention as an improvement over the weakness of the wet non-woven fabric, which is a weakness due to the short fiber length. However, in the prior art of this specification, a fiber length of about 3 to 7 mm is generally required in order to uniformly disperse fibers in water, and a nonwoven fabric obtained by processing a wet web having a fiber length of more than 7 mm is required. States that the formation is bad. In other words, this invention cannot be said to take advantage of the advantage of the wet papermaking method, such as good formation. In addition, since the fiber diameter is relatively large, 7 to 25 μm, there is also a problem that drape property, touch, and softness are inferior.

In Japanese Patent Application Laid-Open No. 54-27067, an ultrafine synthetic fiber filament is provided with a non- (difficult) water-soluble sizing agent, bundled into a fiber bundle, cut into 20 mm or less, and made into a paper by a wet papermaking method. A method is described in which this is laminated with a woven fabric, entangled with a high-pressure jet, and then the glue is removed. In this method, the fiber bundle is dispersed by the high-pressure jet,
The dispersed fiber only spreads at that portion, has a direction as a bundle, and has a problem in overall texture and feel.

In Japanese Patent Application Laid-Open No. 53-28709, a web containing splittable fibers is split by a water jet.
Furthermore, a method of performing confounding with a water jet is described. However, this method has a problem that the texture is not uniform in portions where splitting is not performed, and the feel is poor.

In JP-A-53-122869,
Although a method of laminating and entanglement ultrafine fibers of 0.5 denier or less on a knitted or woven fabric is exemplified, there is a problem that the woven or knitted fabric is expensive and has low productivity.

The present invention takes advantage of the characteristics of wet nonwoven fabric, such as good formation, uniformity, and the use of ultrafine fibers.
An object of the present invention is to provide a nonwoven fabric in which the drawbacks of a wet nonwoven fabric such as low strength, poor drape, poor texture, and poor air permeability have been improved.

[0019]

Means for Solving the Problems The present inventors diligently studied the above problems. As a result, ultrafine fibers having a fiber diameter of 7 μm or less were three-dimensionally entangled and obtained by a wet papermaking method using a nonwoven fabric having a specific void diameter, and further using two or more kinds of fibers having a fiber diameter of 7 μm or less having different fiber lengths. By laminating a single layer or a plurality of webs and three-dimensionally entangled with a high-pressure columnar water stream, it is possible to obtain a nonwoven fabric with good sheet formation and excellent drape, texture, air permeability, and strength. I found it. The present invention has been achieved based on these findings.

That is, the present invention relates to a non-woven fabric comprising fibers having a fiber diameter of 7 μm or less, wherein the fibers constituting the non-woven fabric are wet papermaking.
This is a nonwoven fabric which is formed into a sheet by a method, is three-dimensionally entangled by a water flow, and has a maximum void diameter value within 5 times the average void diameter.

Further, the present invention relates to a method for producing one or more fibers having a diameter of 7 μm.
m: fiber length (L) to fiber diameter (D) ratio (L / D)
Organic fiber of 2000 or less, one or more types of fiber diameter 7μm
The following 2000 <(L / D) contains an organic fiber is ≦ 6000, 2 in the following fiber diameter 7μm on the weight of the nonwoven fabric
000 <(L / D) ≦ 6000 organic fibers for 10 to 90
It is a nonwoven fabric containing weight% .

When one or more fibers have a fiber diameter of 7 μm or less, L
Organic fiber with / D of 2000 or less, 1 or more fiber diameter 7
It contains an organic fiber satisfying 2000 <(L / D) ≦ 6000 at μm or less, and has a fiber diameter of 7 μm or less based on the weight of the nonwoven fabric.
2000 <(L / D) ≦ 6000 organic fibers
A slurry is prepared so as to contain 0 to 90% by weight, and a single layer or a plurality of webs obtained by a wet papermaking method using the slurry are laminated, placed on a support, and a high-pressure columnar water stream is injected from above. , Fibers are entangled three-dimensionally and dried
A method for producing a nonwoven fabric.

Hereinafter, the present invention will be described in detail.

The fibers used in the nonwoven fabric of the present invention have a fiber diameter of 7 μm or less. More preferably, the ratio (L / D) of the fiber length (L) to the fiber diameter (D) is 2000 when the fiber diameter is 7 μm or less.
<(L / D) ≦ 6000 or less organic fiber (hereinafter high L)
/ D fiber), and a fiber diameter of 7 μm or less, L / D
Organic fiber with a molecular weight of 2000 or less (hereinafter referred to as low L / D fiber)
It is.

These organic fibers include polyester fibers, polyolefin fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, nylon fibers, and the like.
Regenerated cellulose fibers and the like are used. The polyester fiber refers to a fiber composed of homopolymer and copolymer such as polyethylene terephthalate, polybutylene terephthalate, and modified polymers of these polymers. Polyolefin fibers are polypropylene, polyethylene,
Fibers composed of homopolymers and copolymers such as polystyrene and their modified polymers. Polyacrylonitrile fiber refers to acrylic fiber, modacrylic fiber and the like. The polyvinyl alcohol fiber refers to a fiber made of polyvinyl alcohol. Polyamide fibers refer to fibers made of polymers such as nylon 6 and nylon 66.

The organic fiber used in the present invention is the above-mentioned 2
It may be in the form of a composite fiber composed of more than one kind of polymer. The cross-sectional shape of the fiber may be a so-called irregular cross-sectional shape such as a triangular, Y-shaped, T-shaped, U-shaped, star-shaped, dog-bone-shaped as well as a circular or elliptical shape.

When the fiber diameter of these organic fibers is more than 7 μm, the obtained nonwoven fabric has an unfavorable touch and drape property. When the fiber diameter is 5 μm or less, a nonwoven fabric having more excellent touch and drapability can be obtained.

The high L / D fiber and the low L / D fiber may be fibers having the same composition or fibers having different compositions.

The organic fibers having a fiber diameter of 7 μm or less used in the present invention preferably have low rigidity. The fibers having too high rigidity are difficult to be entangled even in the range of L / D of the present invention, and when a high-pressure columnar water flow is used, the arrangement of the fibers becomes irregular and the sheet becomes uneven or the sheet is damaged. Problem.

Further, the high L / D fiber is based on the weight of the nonwoven fabric.
The content is preferably 10 to 90% by weight. If the amount is less than 10% by weight, three-dimensional entanglement is not performed firmly, and the strength of the nonwoven fabric is reduced. If it exceeds 90% by weight, it is necessary to remarkably lower the dispersion concentration, and the productivity becomes worse. In addition, suction is required to be very large to perform dewatering from the papermaking wire, and a large amount of energy is required.

Naturally, in addition to the above-mentioned fibers, it is possible to include a small amount of fibers other than those limited by the present invention and other materials in the nonwoven fabric, but a range that impairs the performance of the nonwoven fabric of the present invention. Should not be.

Next, the pore size of the nonwoven fabric of the present invention will be described. The void diameter is measured as a maximum void diameter and an average void diameter by a bubble point method and a mean flow point method described in ASTM F-316.

The maximum void diameter of the nonwoven fabric of the present invention is 25
0 μm or less, and the average void diameter is preferably 150 μm or less. When the maximum void diameter is larger than 250 μm, and when the average void diameter is larger than 150 μm, entanglement is insufficient and a strong nonwoven fabric cannot be obtained. It is considered that the fibers are entangled and entangled strongly when the void diameter is reduced.

Further, it is necessary that the pore diameter is within the above range and the maximum pore diameter is within a range of 5 times or less with respect to the average pore diameter, in order to uniformly entangle the fibers.
If the maximum void diameter exceeds 5 times, formation is poor, the nonwoven fabric lacks uniformity, and confounding is not performed firmly,
The drapability and feel of the nonwoven fabric are inferior.

As described above, by measuring the maximum and average void diameters of the nonwoven fabric, it is possible to evaluate not only the entangled state, the formation and uniformity of the nonwoven fabric, but also the touch and drape property from which these are derived.

Next, the method for producing the nonwoven fabric of the present invention will be described.

It is necessary to pay particular attention to the high L / D fiber in the defibration and dispersion steps so that the fiber does not become entangled as compared with the low L / D fiber. As described above, the decrease in formation due to the tying of the web obtained by wet papermaking greatly affects the performance of the nonwoven fabric.

For disintegration and dispersion, a rotary type can be used, but in particular, a reciprocating reversal type is preferable in order to complete the dispersion and maintain a uniform dispersion state. Before disintegrating the fibers, a method of uniformly dispersing the dispersant in an aqueous solution in advance, or pre-soaking the fibers in a solution of about 1% of the dispersant, in order to promote the disintegration of the fibers, This is effective in preventing unity after disaggregation.

The order of dispersion of the fibers is not particularly limited. In particular, in the case of uniformly dispersing effectively, low L / D fibers, which are easy to disperse, are first dispersed, and then the slurry is added to the slurry. It is desirable to introduce and disperse high L / D fibers. When fibers are charged in this order, fiber bundling does not easily occur.

This is because the low L / D fiber acts as a kind of interference agent, enters between the high L / D fibers once defibrated, and maintains the high L / D fiber distance. Therefore, it is considered that the fibers are entangled during dispersion or after the dispersion is completed, thereby preventing the fibers from binding. As described above, when low L / D fibers are mixed, an unexpected effect of not only improving the dispersion density but also preventing the binding is obtained.

The stirring is preferably performed promptly for disaggregation so that the fibers are not entangled. If the fibers are insufficiently disintegrated by stirring for a short time, it is preferable to increase the stirring speed instantaneously, apply an impact to the undisintegrated fiber bundle, and promote disintegration. The stirring speed is only temporarily increased, and if the stirring time is long, binding between fibers is formed, which is not preferable. When disaggregation is not performed once, it is preferable to repeat the process of slowing down the stirring speed and then increasing the stirring speed again for a short time.

Next, the dispersion is performed under gentle stirring as much as possible to prevent the binding of the fibers. The concentration of the pre-disintegrated slurry is further reduced by adding water, and then the tackifier is quickly added. During this time, stirring is performed as slowly as possible as described above. Thus, a uniformly dispersed slurry is prepared. Here, “uniform” means a state in which fibers are not substantially bound or aggregated during stirring.

In the present invention, not only high L / D fibers but also low L / D fibers are mixed for papermaking. Therefore, for the reasons described above, the dispersion concentration is increased more than only high L / D fibers. It is possible to increase the papermaking available basis weight and improve the efficiency of papermaking.

Using the slurry thus prepared, papermaking can be performed by a wet papermaking method. continue,
It is possible to perform three-dimensional entanglement using a high-pressure columnar water flow, but there are two methods of entanglement from papermaking: an on-machine method of continuous entanglement after papermaking, and an off-state method of once entanglement after papermaking. Machine method is conceivable.

The on-machine method is a method in which entanglement is continuously performed after papermaking, and is preferable as a method for simplifying the process. In the on-machine manufacturing method, the web is already wet and there is no need to saturate in water before entanglement. Further, it is effective for producing a nonwoven fabric having a relatively low basis weight and a nonwoven fabric which is easily entangled.

In the off-machine method, it is necessary to dry the paper web once to obtain a sheet, and it is necessary to use a binder for binding fibers.

As the binder, a binder soluble in water or hot water is preferably used. Examples of the material include polyvinyl alcohol (PVA), modified polymer resins such as polyester and polyolefin, and fibrous materials thereof. The method of adding a binder may be a method of mixing a fibrous material into a slurry, a method of impregnating a web into a binder solution after forming a web, a method of applying, spraying, or a combination of both. However, the present invention is not limited to the above method.

The content of the binder is preferably in the range of 1 to 10% by weight based on the weight of the sheet obtained by the wet papermaking method.
If it is less than 1% by weight, the sheet strength is weak, and it is difficult to handle after drying the paper. If it exceeds 10% by weight, a large water pressure is required for confounding, which is not preferable. Further, the strength between the laminated layers is low.

The web formed by wet papermaking and formed can be dried by a usual drying method using a Yankee dryer, a multi-cylinder cylinder dryer, an air dryer, or the like.

When entanglement is performed by the off-machine method, the fibers are fixed via a binder, and the formation of the fibers by water flow is hardly reduced. Further, it is possible to laminate an arbitrary number of paper-dried sheets. For this reason, it is effective to use a nonwoven fabric having a relatively large basis weight and a case of performing entanglement under strong conditions.

As described above, since the binder component is composed of a component soluble in water or hot water, it can be eluted in the step of entanglement of the fibers with a high-pressure columnar water flow.
Further, it is also effective to saturate with water or hot water before, after, or before and after processing with a high-pressure columnar water flow.

As described above, the off-machine method and the on-machine method can be appropriately selected depending on the fiber material and basis weight of the nonwoven fabric to be produced. Further, both methods may be used in combination.

Next, a method for performing three-dimensional entanglement using a wet paper-made web or a dried sheet will be described. In the entanglement method, a single layer or a plurality of sheets of a web or a sheet are laminated, placed on a support of about 50 to 200 mesh, and a water flow is driven from above to perform three-dimensional entanglement of the fibers. The conditions for performing confounding firmly and properly according to the purpose are described below.

The diameter of the nozzle for injecting the water stream and entanglement of the fibers is preferably in the range of 10 to 500 μm in order to perform entanglement firmly and to keep the formation good. The interval between the nozzles is preferably 10 to 1500 μm.

These nozzles are used for web, sheet type,
In consideration of the basis weight, processing speed, and water pressure, the number of nozzle heads can be changed and used within a range where sufficient confounding can be obtained. Also, the number of confounds can be arbitrarily selected.

The water pressure is preferably used in the range of 10 to 250 kg / cm ² . When confounding by on-machine method 10
~ 100kgf / cm ² , 50 ~ ² for off-machine
More preferably, it is performed at 50 kg / cm ² . The processing speed can be used in the range of 15 to 200 m / min.

If the water pressure of confounding is low, sufficient confounding cannot be obtained. On the other hand, if the water pressure is higher than necessary, formation may be disturbed or the sheet may be damaged, which is not preferable.

The water pressure is gradually increased from the initial stage to the final stage of processing, so that the surface quality is not impaired.
Strong confounding becomes possible. Further, the nozzle diameter and / or the nozzle interval can be sequentially reduced, which is also preferable in that the surface quality of the nonwoven fabric is improved. Further, the surface quality can be further improved by rotating the nozzle header, oscillating it left and right, or oscillating the support wire of the web left and right. Furthermore, after entanglement, it is also possible to improve the surface quality by inserting a wire mesh of 40 to 100 mesh between the nozzle and the web to sprinkle the columnar water stream and spray it on the web. further,
It is also possible to easily improve the surface quality by lowering the water pressure immediately before the end of the confounding or by lowering the water pressure just before and two rows before.

The confounding method can be performed on one side only or on both sides. Further, after the entanglement is performed, the sheets can be further laminated to perform the entanglement.

After the three-dimensional confounding treatment is performed as described above, excess water is removed by a method such as suction or wet pressing, and then drying is performed using an air dryer, an air through dryer, a suction drum dryer, or the like. Can be.

Naturally, it is possible to entangle the nonwoven fabric with other nonwoven fabrics such as dry nonwoven fabrics, pulp sheets, wet nonwoven fabrics containing fibers outside the scope of the present invention, etc. from one side or both sides. Needless to say, it should not be in a range that hinders the purpose of the above.

The nonwoven fabric with good formation of the present invention obtained by the above-mentioned method can be subjected to post-processing such as bending, resin impregnation, and water-repellent processing, thereby providing new performance. Can be granted.

The use of the nonwoven fabric of the present invention having good formation is considered for medical and hygiene materials. It is rich in drapability, and particularly fine in fiber diameter of 7 μm or less, so it is soft, has good touch, and has excellent barrier properties, and is suitable for applications such as masks and surgical gowns.

Further, although the fiber diameter is fine,
It is suitable for use as a liquid or gas filter because it has good air permeability, and is subjected to a water-repellent treatment with a water-repellent agent to improve liquid barrier properties.

Further, it is suitable for artificial leather, particularly as a base material for high-quality suede-like artificial leather because of its good texture and good texture. As described above, examples of the use of the nonwoven fabric of the present invention have been described, but it should be noted that the use is not limited to these.

[0066]

According to the present invention, the ultrafine fibers are three-dimensionally entangled and have a specific void diameter. As a result, the formation is uniform and the skin feels good, and the drape, texture, air permeability and strength are excellent. A good nonwoven fabric, which could not be obtained with the nonwoven fabric, can be obtained. Further, by using the ultrafine fibers in combination with the high L / D fibers and the low L / D fibers, it is possible to significantly improve the dispersibility during wet papermaking, and as a result, it is composed of the ultrafine fibers. But it was not possible to obtain with a conventional nonwoven fabric that was uniform, had good touch, good texture, air permeability, and strength.
A good nonwoven fabric can be obtained with high efficiency.

[0067]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
All parts and percentages described in the examples are by weight. The fineness indicates an approximate value.

The rigidity shown in the examples is JIS-L1
The measurement was performed using the 45-degree cantilever method described in No. 096, and the average value in the vertical and horizontal directions was shown. As air permeability, JIS-B99
The pressure loss was measured at a wind speed of 5.3 cm / sec according to Model No. 08. Under the condition at the time of air permeability measurement as a barrier property,
The collection efficiency of 0.3 μm DOP (dioctyl phthalate) aerosol was measured. The pore size of the nonwoven fabric is ASTM
Maximum void diameter (MAX), average void diameter (M) according to the bubble point method and mean flow point method described in -F-316.
FP).

The formation of the nonwoven fabric was visually evaluated on a four-point scale: ◎ is very good, 良 い is good, △ is slightly bad, and × is bad. ◎ is very good, ○
The evaluation was made on a four-point scale of good, poor, and bad.

In this example, a sheet obtained by the wet papermaking method is referred to as a sheet, and a sheet obtained by three-dimensionally entangled is referred to as a nonwoven fabric.

Examples 1-3, Comparative Example 1 Polyethylene terephthalate (PET) fiber having a fineness of 0.1 denier and a fiber length of 10 mm (fiber diameter 3 μm, L / D =
3.3 × 10 ³ ) (high L / D), fineness 0.1 denier,
PET fiber with a fiber length of 5 mm (L / D = 1.7 × 10 ³ )
The mixing ratio of (low L / D) is shown in Table 1. For a total of 100 parts of these fibers, a fineness of 1 denier and a fiber length of 3
mm hot water soluble polyvinyl alcohol fiber (VPB10
7, Kuraray Co., Ltd.).

First, polyvinyl alcohol fiber, low L /
The D fiber is stirred at high speed with a pulper to disintegrate. Water was added to the slurry, and the slurry was transferred to a chest equipped with a reciprocating rotary stirrer (Agitator, manufactured by Shimazaki Seisakusho). The high L / D impregnated in a 1% nonionic dispersant solution was added while gently stirring the agitator. The fiber was put in water and stirred. The process of temporarily increasing the stirring and then returning to gentle stirring was repeated three times. Then, immediately, polyacrylamide 0.1
% Solution (viscous agent), and after agitation is accelerated temporarily,
Slow stirring was performed. Thus, a uniform slurry was prepared. The mixing ratio of (high L / D fiber) / (low L / D fiber) is shown in Table 1. Using the slurry, a web having a width of 50 cm and a basis weight of 20.5 g / m ^{2 was formed with} a fourdrinier paper machine and dried at 110 ° C. with a Yankee dryer to obtain a sheet.

[0073]

[Table 1]

Four sheets are laminated, and the nozzle head is
The confounding was performed with a columnar water flow using a head. The nozzle of the first head has a nozzle diameter of 120 μm, the nozzle interval is 0.6 mm, the water pressure is 100 kgf / cm ^{2 in} two rows, and the nozzle diameter of the second head is 120 μm.
m, nozzle spacing 0.3 mm, water pressure in one row 100 kgf / cm ² ,
The third head has a nozzle diameter of 100 μm and a nozzle interval of 0.3 m
m, the water pressure in one row is 120 kgf / cm ² . A 100-mesh support made of stainless steel was arranged under the laminated sheet, and the fiber was firmly entangled by passing the laminated sheet under the above-mentioned water flow. Similarly, the same processing was performed on the back surface. The confounding speed was 20 m / min. The entangled sheet was dried at 120 ° C. using a suction through dryer to obtain Examples 1 to 3 and Comparative Example 1 nonwoven fabric. Table 2 shows the measurement results.

In Comparative Example 1, since there were many low L / D fibers,
Sufficient confounding is not obtained and the strength is weak. In addition, the surface quality and formation were disturbed by the water current, and the non-woven fabric was inferior in drapability and touch.

[0076]

[Table 2]

Example 4 The fiber length of the high L / D fiber was 7 mm (L / D = 2.3 × 10
³ ), and a nonwoven fabric was obtained in the same manner as in Example 1 except that the mixing ratio of (high L / D fiber) / (low L / D fiber) was 85/15. Table 2 summarizes the composition and the like, and Table 4 shows the measurement results.

Example 5 The fiber length of high L / D was 15 mm (L / D = 5.0 × 1)
0 ³ ), the fiber length of low L / D is 3 mm (L / D = 1.0 × 1)
0 ³ ), and a nonwoven fabric was obtained in the same manner as in Example 1 except that the mixing ratio of (high L / D fiber) / (low L / D fiber) was 20/80. Table 2 summarizes the composition and the like, and Table 4 shows the measurement results.

Comparative Example 2 A fiber having a high L / D length of 20 mm (L / D = 6.7 × 10
^A nonwoven fabric was obtained in the same manner as in Example 5 except that ³ ) was performed. Table 2 summarizes the composition and the like, and Table 4 shows the measurement results.

The sheet obtained by wet papermaking and drying had many undisintegrated portions of fibers and binding. L / D is 600
It is considered that fibers exceeding 0 are difficult to disintegrate even when the disintegration concentration is reduced, and that the fibers are entangled during stirring. Due to this, the entanglement was insufficient, and the entangled nonwoven fabric had low strength and poor texture, resulting in poor touch and drape.

Example 6 The fineness of the high L / D fiber was 0.3 denier and the fiber length was 15
mm (fiber diameter 5 μm, L / D = 3.0 × 10 ³ ), and a nonwoven fabric was obtained in the same manner as in Example 3. Table 1 summarizes the composition and the like, and Table 2 shows the measurement results.

Comparative Example 3 The fineness of the high L / D fiber was 1 denier and the fiber length was 51 mm.
(Fiber diameter 10 μm, L / D = 5.1 × 10 ³ ), and a nonwoven fabric was obtained with the same composition as in Example 2. Table 2 summarizes the composition and the like, and Table 4 shows the measurement results.

In the sheet produced by the paper machine, many undisintegrated portions of fibers and binding were observed. Although L / D is within the range of the present invention, it is considered that the fiber diameter is large, the fiber length is long, the fiber is difficult to disintegrate, and the fibers are entangled during stirring. As a result, the entanglement of the nonwoven fabric was insufficient, the maximum void diameter exceeded 300 μm, the measurement was impossible, the formation, the touch, the texture were poor, and the drapability was poor.

[0084]

[Table 3]

Example 7 Example 1 A slurry was prepared using the same fiber and composition as described above.
A sheet having a basis weight of 82 g / m ² was prepared by wet papermaking, and the sheet was entangled with a single layer to obtain a nonwoven fabric. Table 4
Table 5 shows the measurement results.

Example 8 Two sheets obtained in Example 1 were laminated, and the fibers were entangled by a high-pressure columnar water flow. However, the confounding conditions are that the water pressures of the first head, the second head, and the third head are 60, 65, respectively.
A non-woven fabric was obtained in the same manner as in Example 1 except that the weight was 75 kgf / cm ² . Table 4 summarizes the composition and the like, and Table 5 shows the measurement results.

Further, one sheet obtained in Example 1 was laminated on this web, and the web was entangled only from the side laminated with the same water pressure. Further, on the opposite side of the further lamination, one sheet obtained in Example 1 was laminated and entangled with the same water pressure,
Hereinafter, a nonwoven fabric was obtained in the same manner as in Example 1.

In the present invention, it was confirmed that a good nonwoven fabric could be obtained even if the lamination method was changed.

Example 9 Using the same high L / D fiber and low L / D fiber as in Example 1,
A slurry was prepared without using VA fibers, and the basis weight was 82 g / m ^2.
Was made by wet papermaking, and subsequently, a high-pressure columnar water stream was continuously jetted to perform a three-dimensional entanglement treatment on the front and back surfaces. However, the water pressure of confounding is 70 kgf / cm ² at the first head,
90 kgf / cm ^{2 for} the second head, 100 kgf / c for the third head
a m ^2.

Example 10 The web immediately after entanglement obtained in Example 1 was dried at 80 ° C. before drying.
Passed through the hot water. Thereafter, drying was performed in the same manner as in Example 1. Table 4 summarizes the composition and the like in Table 4.
Shows the measurement results.

Comparative Example 4 Using the same high L / D fiber and low L / D fiber as in Example 1, 6 parts of heat fusible fiber were mixed with 100 parts of these fibers to prepare a slurry. The wet-laid paper was dried, and the physical properties of the obtained sheet having a basis weight of 80 g / m ² were measured. Table 4 shows the composition and the like, and Table 5 shows the measurement results.

Although the fiber length is within the range of the present invention, since it was produced only by the wet papermaking method, it became a nonwoven fabric having a high density and tightness, and was inferior in texture and drapability. Also, the air permeability was extremely inferior to the spunlace nonwoven fabric of the present invention.

[0093]

[Table 4]

[0094]

[Table 5]

Example 11 A high L / D fiber was an acrylic fiber having a fineness of 0.1 denier and a fiber length of 10 mm (fiber diameter 3.5 μm, L / D = 2.9 × 1
0 ³ ) A non-woven fabric was obtained in the same manner as in Example 2 below, using low-density fibers as acrylic fibers (L / D = 1.7 × 10 ³ ) having a fineness of 0.1 denier and a fiber length of 6 mm. However, an anionic dispersant was used as the dispersant for the acrylic fiber. Table 6 summarizes the composition and the like, and Table 7 shows the measurement results.

The obtained nonwoven fabric had a good drape property and a soft touch, and had a good texture. Good results were obtained with different materials.

Example 12 Two sheets each having a basis weight of 20 g / m ² obtained in Example ^{2 and} a sheet having a basis weight of 20 g / m ² obtained in Example 11 were used, and a total of four sheets were laminated. In the same manner as in Example 1, a nonwoven fabric was obtained. Table 6
Table 7 shows the measurement results.

It has been confirmed that good confounding can be obtained even between sheets of different materials.

Example 13 The uniformly dispersed slurry of Example 2 and the uniformly dispersed slurry of Example 11 were prepared at the same concentration and mixed in the same amount. No fiber aggregation or fiber entanglement was found in the slurry. Using the mixed slurry, a sheet having a basis weight of 20 g / m ² was prepared, and four sheets were laminated, and a nonwoven fabric was obtained in the same manner as in Example 2 below. Table 6 summarizes the composition and the like, and Table 7 shows the measurement results.

A good nonwoven fabric could be obtained by using a sheet obtained by mixing fibers of different materials and making a paper.

[0101]

[Table 6]

[0102]

[Table 7]

[0103]

The nonwoven fabric of the present invention, which is made of ultrafine fibers having a specific fiber diameter, is entangled three-dimensionally and has a specific void diameter, and further has a specific fiber length to fiber diameter ratio (L) The nonwoven fabric of the present invention, which is composed of ultrafine fibers having high L / D and organic fibers having low L / D, and having these fibers three-dimensionally entangled, has a good texture and a good feel, Excellent drape and good ventilation. In addition, low L /
By mixing the organic fibers of D in a specific ratio, the dispersibility is improved without significantly impairing the performance of the nonwoven fabric, and the productivity can be increased. These are realized for the first time with a well-formed nonwoven fabric produced by the specific method of the present invention.

Claims (3)

(57) [Claims] 1. A non-woven fabric comprising fibers having a fiber diameter of 7 μm or less, wherein the fibers constituting the non-woven fabric are formed into a sheet by a wet papermaking method.
A nonwoven fabric which is entangled three-dimensionally by a water flow and has a maximum void diameter value within 5 times the average void diameter. 2. An organic fiber having at least one fiber diameter of 7 μm or less and a fiber length (L) to fiber diameter (D) ratio (L / D) of 2,000 or less, and 2,000 or less of at least one fiber diameter of 7 μm or less.
(L / D) ≤ 6000, and 2000 <(L / D) with a fiber diameter of 7 μm or less based on the weight of the nonwoven fabric.
The nonwoven fabric according to claim 1, which contains 10 to 90% by weight of an organic fiber of ≤ 6000. 3. An L / D with one or more fiber diameters of 7 μm or less.
Is 2000 or less organic fiber, 1 or more kinds of fiber diameter 7μm
In the following, organic fibers satisfying 2000 <(L / D) ≦ 6000 are contained.
A slurry is prepared such that D contains 2,000 or less organic fibers of 10 to 90% by weight, and a single layer or a plurality of webs obtained by a wet papermaking method using the slurry are stacked, and the web is placed on a support. A method for producing a nonwoven fabric, characterized by injecting a high-pressure columnar water stream from above, confounding fibers three-dimensionally, and drying.