JP2002317370A - Nonwoven fabric composed of fiber with net structure, and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonwoven fabric having a dense structure composed of an ultrafine fiber with a net structure, capable of counterbalancing the defect possessed by a olefinic polymer with the defect possessed by an ester-based polymer, and capable of using these merits. SOLUTION: This nonwoven fabric is the one constituted of the fibrillated fiber with the net structure. The fiber can be produced by a flash spinning method, and is constituted so that the first fibrillated fiber comprising the olefinic polymer component and the second fibrillated fiber comprising the ester-based polymer component, mutually having no compatibility may be present in a mixed state regulated so that the mixing ratio of the olefinic polymer component to the polyester-based polymer component may be (5/95)-(95/5) by weight. The nonwoven fabric has the net structure bonded between fibrillated fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric which is composed of fibers having an extremely fine network structure and is made of a mixture of incompatible polymers, and which has a dense structure, and a method for producing the same.

[0002]

2. Description of the Related Art As a method for obtaining a non-woven fabric using ultrafine fibers, a sea-island type multi-component filament is spun and then a part of a polymer component is removed with a solvent to obtain a fiber. It is known that a nonwoven fabric is obtained by adhering a nonwoven fabric. Further, it is known to apply a so-called melt blown method, in which a molten polymer is extruded from a spinning nozzle and drawn by a heated fluid to be thinned.
However, the method of removing a part of the polymer component of the multi-component filament with a solvent requires various steps to dissolve and remove the polymer. According to the melt blown method, extremely fine fibers can be obtained, but since the melt blown method involves thinning at the stage of the molten polymer, there is little stretching orientation and crystallization, and the obtained fibers are extremely weak. Has disadvantages.

On the other hand, as a method for obtaining ultrafine fibers from a polymer solution, a so-called flash spinning method has been proposed. The flash spinning method is disclosed in US Pat.
As described in No. 19, a solution of a polymer in a low boiling point solvent is extruded from a spinning nozzle to instantaneously vaporize the solvent.

[0004]

However, since the fibers obtained in this formulation consist of a single polymer component for any material, they have the inherent disadvantages of polymers, which is a disadvantage of the products. However, there is a problem that a limitation is imposed on the development of the application. The same applies to the technology disclosed in JP-B-41-6215 and JP-A-1-97256. Specifically, the olefin-based polymer is excellent in lightness, but has a low modulus, has no feeling of use or wearing, and has a unique slimy feeling. Ester polymers are inherently suitable for high-strength fibers and have a high modulus, but have not been put to practical use because high-strength fibers have not been obtained by flash spinning.

The present invention solves the above-mentioned problems, and in particular, cancels out the disadvantages of the olefin-based polymer and the disadvantages of the ester-based polymer, and makes use of the advantages of these nonwoven fabrics made of ultrafine network-structured fibers. And a method of manufacturing the same.

[0006]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.

[0007] The nonwoven fabric having a dense structure according to the present invention is composed of a fibril fiber having a network structure, and this fiber is obtained by a flash spinning method and is not compatible with each other. The first consisting of
Of fibril fiber and ester-based polymer component
And the fibril fibers are present in a mixed state, and the mixing ratio between the olefin polymer component and the ester polymer component is in the range of 5/95 to 95/5 by weight, and the nonwoven fabric is The fibril fibers of the network structure are adhered entirely or partially.

The method for producing a nonwoven fabric having a dense structure according to the present invention comprises the steps of: mixing a mixed polymer of an olefin polymer and an ester polymer which are not compatible with each other with an olefin polymer and an ester polymer. Is 5 by weight.
/ 95 to 95/5 in a solvent under high temperature and high pressure to form a single bath phase, and then through a nozzle under a condition where the polymer and the solvent are phase separated. The fiber is spun to produce a fibril fiber having a network structure in which a first fibril fiber composed of an olefin polymer component and a second fibril fiber composed of an ester polymer component are present in a mixed state, and this fiber is used as a web. Thereafter, the web is thermocompression-bonded using a group of rolls to bond the fibril fibers having a network structure entirely.

Another method for producing a nonwoven fabric based on the present invention is to mix a mixed polymer of an olefin polymer and an ester polymer which are incompatible with each other by mixing the mixed polymer of the olefin polymer and the ester polymer. The ratio is 5/95 to 9 by weight
In a solvent, the mixture is dissolved under a high temperature and a high pressure under a solvent to form a single bath phase. Thereafter, the polymer and the solvent are spun from a nozzle under a phase-separated state. Thus, a fibril fiber having a network structure in which a first fibril fiber composed of an olefin-based polymer component and a second fibril fiber composed of an ester-based polymer component exist in a mixed state, and this fiber is used as a web. The web is partially thermocompression-bonded using an embossing machine to partially bond the fibril fibers having a network structure.

As described above, according to the present invention, it is possible to obtain a nonwoven fabric having a dense structure constituted by highly fibrillated ultrafine fibers. Of these, non-woven fabrics in which the fibers of the net structure are bonded over the whole are envelopes, packaging materials,
It is suitable for general-purpose applications such as floppy sleeves, waterproof materials, labels, heat insulating materials, synthetic paper, protective clothing as protective materials for sanitary materials, curtains, sheets, wipers, filters, and house wraps. In addition, non-woven fabrics in which the fibers of the net-like structure are partially adhered to each other include clothes, heat insulating materials, protective clothing for medical hygiene materials, curtains, sheets, wipers, filters,
Suitable for general-purpose applications such as house wraps, tents and artificial leather.

[0011]

Next, the fibers having a network structure constituting the nonwoven fabric of the present invention will be described in detail. The term “fiber having a network structure” as used in the present invention refers to a group of fibers in which fibril fibers equivalent to 0.01 to 10 μm are three-dimensionally networked and endlessly formed in the longitudinal direction of the yarn.

It is necessary that the components constituting the fibers are composed of polymer components having no compatibility with each other. This incompatibility with each other means that the mixed polymer components are present independently, meaning that the fibers have the essential fiber properties of the individual polymers. Typically,
It is known that mixed fibers of polymers that are incompatible with each other are liable to be divided into each other by physical force. Since the fibers of the present invention are not compatible with each other, fibril fibers of a very fine polymer alone are mainly constituted. A specific combination of polymer components for this purpose refers to a combination of an olefin polymer and an ester polymer.

Among the polymer components constituting the fiber, examples of the olefin-based polymer include polyethylene, polypropylene, a copolymer mainly composed of ethylene, a copolymer mainly composed of propylene, and the like.

Among these polymers, the viscosity of the ethylene polymer is preferably from 0.3 to 30 g / 10 minutes, as measured by the method of ASTM-D-1238E. Melt index value 0.3g / 1
If the time is less than 0 minutes, the viscosity of the mixed solution becomes too high, and it is difficult to obtain ultrafine fibril fibers. On the other hand, if the melt index value exceeds 30 g / 10 min, the strength of the fiber itself is reduced, and the slimy feeling and tackiness of the fiber are increased, so that the fiber tends to be poorly handled.

[0015] The viscosity of the propylene polymer is ASTM-
The melt flow rate measured by the method of D-1238L is preferably 1 to 40 g / 10 minutes. If the melt flow rate value is less than 1 g / 10 minutes, the viscosity of the mixed solution becomes too high, and it becomes difficult to obtain ultrafine fibril fibers. On the other hand, if the melt flow rate exceeds 40 g / 10 minutes, the strength of the fiber itself is reduced, and the slimy feeling and the tackiness of the fiber are increased, so that the fiber tends to be poor in handling.

Examples of the ester polymer which is another polymer component constituting the fiber include polyethylene terephthalate and polybutylene terephthalate. In addition to these as a main component, isophthalic acid, phthalic acid, glutaric acid, adipic acid, sulfoisophthalic acid, diethylene glycol, propylene glycol,
Those containing 1,4-butanediol, 2,2-bis (4-hydroxyethoxyphenyl) propane, bisphenol A, polyalkylene glycol, or the like as a copolymer component in a range of up to 40 mol% are equally used. Can be. The viscosity of the polymer was 0.2 at a mixing ratio of 1/1 (weight ratio) of tetrachlorethane and phenol at 20 ° C.
It can be applied from a fiber grade having a relative viscosity ηrel measured at 5% of about 1.3 to 1.6 to a high viscosity resin (relative viscosity 1.7) produced by solid-state polymerization. The higher the viscosity of the polymer, the higher the fiber strength, which is the preferred direction.

The components constituting the fibers must be composed of a mixed polymer component which is incompatible with each other and has at least a melting point of 100 ° C. or higher. The reason why it is necessary that they have no compatibility with each other is as described above, and the reason that the polymer components each having a melting point of 100 ° C. or more are required is based on regulations from a practical viewpoint. Those with a melting point of less than 100 ° C will melt even in boiling water,
From the practical point of view, it is extremely limited in the development of applications. Therefore, the melting point is more preferably 120 ° C. or higher. Next, "at least composed" means that the mixed polymer component accounts for 50% by weight or more in the composition ratio in the fiber. If it is less than 50% by weight, the characteristics of the olefin polymer and the ester polymer are lost, which is not preferable.

In this fiber, the mixing ratio (weight ratio) of the olefin polymer and the ester polymer is 5 / 95-9.
It is preferably 5/5. If the mixing ratio of the olefin-based and ester-based polymers is smaller than this range, the characteristics of the respective polymers are lost, which is not preferable. Specifically, when the mixing ratio of the olefin polymer is less than 5% by weight, the lightness and the fiber strength are reduced. When the mixing ratio of the ester polymer is less than 5% by weight, the modulus of the fiber is reduced, and the stiffness and use / wearing feeling of the fabric are lost, and the unique slimy feeling of the olefin polymer occurs. Will come. Therefore, a more preferable mixing ratio is 15 / 85-8.
5/15, and the most preferable mixing ratio is from 25/75 to
75/25.

Next, one method for producing a fiber having a network structure will be described. In order to produce this fiber, a generally known flash spinning method can be applied. Hereinafter, a specific method thereof will be described.

First, a mixed polymer of an olefin polymer and an ester polymer is prepared by using a solvent in which none of these polymers dissolves at low temperature but dissolves under high temperature and high pressure. And dissolve under high temperature and high pressure. Then, after forming one bath phase, the polymer and the solvent are spun from a nozzle in a state where they are phase-separated. Thereby, the above fiber can be manufactured.

Examples of the solvent include generally known aromatic hydrocarbons such as benzene and toluene, aliphatic hydrocarbons such as butane and pentane and isomers and homologs thereof, and alicyclic hydrocarbons. For example, cyclohexane, unsaturated hydrocarbon and the like can be mentioned. Also, halogenated hydrocarbons such as trichloromethane, methylene chloride, carbon tetrachloride, chloroform, 1,1-dichloro-2,2-difluoroethane, 1,2-dichloro-1,1-difluoroethane, methyl chloride, ethyl chloride, etc. No. Furthermore, alcohols, ethers, ketones, nitriles, amides, fluorocarbons and the like can be mentioned. Furthermore, a mixture of the above-mentioned solvents and the like can be mentioned. In recent years, while global environmental issues have been raised, the use of solvents that destroy the ozone layer, in particular, must be avoided. In view of this environmental problem, preferred solvents for the present invention include methylene chloride, 1,1-dichloro-2,2-difluoroethane, 1,2-dichloro-1,1-difluoroethane, and the like.

The concentration range of the polymer cannot be unconditionally limited depending on the degree of polymerization of the polymer, the kind of the solvent, and the pressurized state. It is preferable that the content be 95% by weight. If the concentration of the polymer is less than 5% by weight, it is difficult to obtain continuous long fibers, and if it exceeds 30% by weight, it becomes a tubular fiber containing bubbles without being fibrillated, and an ultrafine high-strength fibril fiber is formed. It is difficult to obtain. When the solvent concentration is less than 70% by weight, the solution viscosity of the spinning mixed solution becomes too high, so that the dissolution of the polymer is difficult to be uniform, and the fibers tend to be hollow fibers instead of ultrafine fibril fibers. On the other hand, if the content exceeds 95% by weight, the network fiber composed of fibril fibers is not continuous, which is not preferable.

It is very desirable to add and inject nitrogen or the like represented by an inert gas before or after preparing the spinning mixed solution in order to increase the spinning pressure. In particular, when an inert gas is added before the temperature is raised, the deterioration of the polymer is prevented and the temperature-raising property is improved, the solubility of the polymer in the solvent is promoted, and an extremely fine fibril network fiber can be produced. This is convenient.

When producing fibers having a network structure, the stretching and orientation of the fibers are performed by the explosive force accompanying the vaporization of the solvent, and the strength of the fibers is determined by whether or not the fibers are sufficiently stretched and oriented. Often. This explosive power
It is the vaporization power due to the instantaneous speed. The solvent evaporates at a stretch in less than 0.1 seconds, and the concentration of the polymer increases in a short time in the process, and only the mixed polymer is finally precipitated. The mixed polymer precipitated by the evaporation of the solvent is cooled. This cooling process is most important for the strength of the fiber, and in order to obtain a high-strength fiber, sufficient cooling by the flash stream and stretching orientation depending on the speed are required. In the production method of the present invention, since the polymers having no compatibility with each other are used, fibrillation is sufficiently promoted by the flash flow, and extremely fine fibril fibers are produced.

When this production method is carried out, polymers which are incompatible with each other are used. Therefore, even if the polymers are dissolved in a solvent, the polymers are easily separated from each other. Is preferred. The addition of this surfactant is effective for keeping the spinning mixed solution stable in an emulsified state, and generally a nonionic surfactant can be applied.
Examples of the surface lubricant include monoesters of lauric acid, stearic acid, and oleic acid, and polyoxyethylene adducts of lauryl alcohol, stearyl alcohol, and oleyl alcohol. The more uniform the mixed solution, the more extremely fine fibril network fibers can be obtained.

In carrying out this production method, the melting and spinning temperature of the spinning mixture is preferably 170 ° C. or higher and 240 ° C. or lower. Particularly, the ester polymer has a large decrease in viscosity in the presence of a solvent. If the temperature exceeds 240 ° C., the coloring of the fiber may be observed, or the decomposition may be accelerated and a fiber having high strength may not be obtained. Not preferred. Also,
If the temperature is lower than 170 ° C., it is not preferable because it does not become an ultrafine fibril fiber but a tubular fiber having a hollow portion.

[0027] The duration of the dissolved state of the spinning mixture during the execution of this production method cannot be unconditionally limited because of the balance between the melting and spinning temperatures. That is, when the temperature is high, the dissolution duration needs to be as short as possible, and when the temperature is relatively low, the dissolution duration can be long. If the dissolution duration is intentionally indicated, the dissolution duration is preferably 5 minutes or more and 90 minutes or less. If the duration of dissolution of the spinning mixture exceeds 90 minutes, the ester polymer may be colored or thermally decomposed, or the fiber strength may be reduced. When the dissolution duration is less than 5 minutes, the dissolution of the polymer becomes insufficient, which may cause a problem of clogging in the filter or a problem of producing uniform fibers, which is not preferable. .

The pressure at the time of spinning the mixed solution in which the polymer is dissolved is not particularly limited by the amount of the solvent, the concentration of the polymer, and the amount of the inert gas added, but is usually preferably 60 kg / cm ² or more. If it is less than 60 kg / cm ² , the explosive power at the time of flash spinning is reduced, and the orientation of the fiber is reduced, so that a high-strength fiber cannot be obtained. Further, there is a problem that the ejection becomes non-uniform, and it is not possible to spin out fibers in a stable high fibril state. The upper limit pressure is not particularly limited, but is 180 kg / cm ² from the viewpoint of suppressing the decrease in viscosity of the polymer.
Is preferred.

When flash spinning is performed, the spinning mixed solution is spun under autogenous pressure or through a pressure drop chamber. A generally known nozzle can be used for the spinning.

The polymer or the spinning mixed solution contains a matting agent, a light-proofing agent, a heat-resistant agent, a pigment, a fiber-opening agent, a weathering agent, an ultraviolet absorber, a heat storage agent, a stabilizer and the like generally used for fibers. Can be added within a range that does not impair the effects of the present invention.

Next, a nonwoven fabric having a dense structure in which the fibers having a network structure are bonded over the entirety and a method for producing the same according to the present invention will be described in detail. This nonwoven fabric is obtained by using the above-mentioned fibers having a network structure.

Here, the nonwoven fabric having a dense structure is
It refers to a nonwoven fabric having an apparent density of 0.2 g / cm ³ or more and the above-mentioned ultrafine network structure fibers being closely bonded. Further, since the fibers constituting the nonwoven fabric of the present invention do not have compatibility with each other, extremely fine polymer-based fibril fibers are mainly constituted. The finer the fiber, the denser the structure when it is made into a nonwoven fabric, and it has a high bacterial barrier property that does not allow even smaller bacteria to pass through than a normal nonwoven fabric.

In the nonwoven fabric of the present invention, it is necessary that the fibers having a network structure are bonded to each other. This means that the fibers having a very fine fibril network structure are closely bonded at the contact points, and are not spot-bonded. In other words, since they are bonded at the contact points between extremely fine fibril fibers,
The resulting nonwoven fabric has an extremely dense structure, and has excellent strength, bacterial barrier properties, water pressure resistance and moisture permeability.

Therefore, the nonwoven fabric of the present invention has a physical strength of 2 g per 100 g / m ² in terms of physical properties.
It is preferably at least 0 kg / 5 cm. Power is 20kg /
If it is less than 5 cm, it cannot be used for general-purpose use, and the use of the nonwoven fabric is extremely limited.

The moisture permeability indicating the performance of dissipating moisture is 1
It is preferably at least 00 g / m ² / hr. 100g moisture permeability
If it is less than / m ² / hr, it will be difficult to dissipate the moisture, and when used as clothing or house wrap, it will be filled with moisture, and eventually will cause dew condensation, causing discomfort or generating mold, and It becomes hygiene. Therefore, the higher the numerical value, the better the moisture permeability.

The water pressure resistance is preferably 50 cm or more. The water pressure resistance is an index of the difficulty of passage of liquid such as water, and is 50 cm.
If the amount is less than the above range, a liquid such as water passes, and at the same time, bacteria also pass therethrough, thereby deteriorating the bacterial barrier property. for that reason,
It cannot be applied to sanitary protection clothing. Therefore, the higher the water resistance pressure, the better.

The method for producing the nonwoven fabric will be described below.
In order to manufacture a nonwoven fabric based on the present invention, first, fibers having a network structure constituting the nonwoven fabric must be manufactured. In manufacturing the fibers having the network structure, the above-described flash spinning method is applied. .

When the mixed solution for spinning is spun out from the nozzle, the flash stream and the precipitated fibers collide with the rotating plate to traverse the fibers of the network structure, and then the fiber is opened. The process of forming the fibers having the network structure is as described above. As the fiber opening method, there are a friction charging method using a rotating plate and a method using a subsequent corona discharge, and either method may be used or both may be used.

After the fibers having the network structure thus opened are deposited on a conveyor to form a fibrous web, the fibrous web is thermocompression-bonded using a group of rolls. As the thermocompression bonding conditions, the temperature condition is set to the melting point of the polymer having the lowest melting point among the polymers constituting the fiber minus 40 ° C. or more and the melting point or less, and the linear pressure condition is set to 0.5 kg / It is better to finally select it as not less than cm and not more than 20 kg / cm. It is more preferable to apply pressure bonding under a roll group at room temperature in advance and then press further under the above-mentioned conditions because the fibril fibers are firmly bonded at the contact points.

The final application of a temperature lower than the melting point of the polymer minus 40 ° C. is not preferred because the adhesiveness between the entire fibers is reduced and the strength of the nonwoven fabric is reduced. Also, when thermocompression bonding at a temperature exceeding the melting point of the polymer, the fibers are melted, and the effect of obtaining ultrafine fibril fibers is reduced,
Not preferred.

On the other hand, if the linear pressure is less than 0.5 kg / cm, it is not preferable because the adhesion between the entire fibers is reduced and the strength of the nonwoven fabric is reduced. In addition, 20kg /
If it exceeds cm, the fiber layer tends to form a film, which is not preferable.

The above-mentioned roll group may be used by combining a steel roll, a rubber roll, and a resin roll. When a steel roll is applied, coating with a fluoroethylene resin, rubber, or the like is preferable because the resulting nonwoven fabric can be prevented from having an unusual luster. 2 to 30 rolls can be used. As a general device for such a roll group, it is most preferable to use a device called a calender roll machine.

In the nonwoven fabric of the present invention, the basis weight can be adjusted by changing the traversing state and the conveyor speed, but a significant basis weight can be changed by laminating the formed web or nonwoven fabric.

Next, a nonwoven fabric having a dense structure in which fibers having a network structure are partially adhered to each other and a method for producing the same will be described in detail. The nonwoven fabric in which the fibers are partially bonded can also be obtained by using the above-described fibers having a network structure.

In this case, it is necessary that the fibers having a network structure are partially adhered to each other in the nonwoven fabric. This means that fibers with extremely fine fibril network structure
It means that the fibers are in a mixed state and are partially adhered to each other with a certain area by a polymer as a low melting point component, but are not totally adhered. In other words, since the extremely fine fibril fibers are partially adhered to each other by the polymer as the low melting point component, the form of the nonwoven fabric is maintained. Since the fibers in the partially unbonded portion are composed of fibers having an extremely fine fibril network structure, the nonwoven fabric becomes a flexible nonwoven fabric having a dense structure, and becomes a nonwoven fabric having excellent strength and moisture permeability. In addition, since it has such a dense structure, it necessarily has a bacterial barrier property.

This partially bonded state can be represented by a bonding area ratio. Adhesive area ratio is the average of 10 times measurement of the ratio of the sum of the areas of the point-bonded parts to the area of the minimum repeating unit using a small piece of non-woven fabric, enlarged and photographed with a scanning electron microscope. Based on the value,
What is measured. The bonding area ratio is preferably 50% or less. If it exceeds 50%, the number of bonded portions increases, the freedom of unfixed fibers in the nonwoven fabric is regulated, and the texture of the nonwoven fabric tends to be hard and lack flexibility. Further, if the bonding area ratio is too small, the morphology as a nonwoven fabric is deteriorated, so that 4% or more is practically preferable. From this, 5% or more and 30% or less are most preferable.

This partially bonded state can also be expressed by the density of bonding points. Adhesion point density was measured using a small piece of non-woven fabric using a scanning electron microscope under magnification, and the ratio of the sum of the number of point-attached parts to the area of the minimum repeating unit was converted per square centimeter. It is calculated by the average value of the measurements.
Bonding point density is preferably 15 / cm ² or more and 120 / cm ² or less. If the number is less than 15 pieces / cm ^2, the morphology of the nonwoven fabric will be reduced, and the abrasion resistance of the nonwoven fabric will be further reduced.
For this reason, the higher the bonding point density, the less practical problems may occur, but if it is too high, the texture of the nonwoven fabric may become hard and lack flexibility. Therefore, the number is preferably 120 / cm ² or less. From the above, a more preferable range is 20 /
cm ² or more and 100 pieces / cm ² or less, may be selected to 30 / cm ² or more and 90 / cm ² or less is the most preferable range.

It is more preferable that both the adhesion area ratio and the adhesion point density are within the above ranges. The forms of these adhesive parts are round, oval, diamond, triangle, T-,-,
Any shape such as a well shape or a lattice shape may be used.

The physical properties of this non-woven fabric were 100 g / m
It is preferable that the strength per ² is 5 kg / 5 cm or more. If the strength is less than 5 kg / 5 cm, practical problems may occur, and the use of the nonwoven fabric is extremely limited.

The non-woven fabric preferably has a compression stiffness of 200 g or less. The compression stiffness indicates the flexibility of the nonwoven fabric, and the smaller the value, the more flexible the nonwoven fabric. Here, the compression stiffness is measured by the following method. First, 50mm in the machine direction (longitudinal direction) of the nonwoven fabric
5 sample pieces each having a sample length of 100 mm in a direction perpendicular to this direction are prepared, and each sample piece is bent in the sample length direction to form a cylindrical shape, and both ends thereof are joined. To make a sample, Tensilon UT manufactured by Toyo Baldwin
Using M-4-1-100, the sample was compressed in the width direction at a compression speed of 50 mm / min, and the stress at the maximum load was measured.
The average value was divided by the basis weight of the nonwoven fabric, and the value converted per 100 g / m ² was defined as the compression stiffness. If the compression stiffness of the nonwoven fabric is more than 200 g, the flexibility is lowered, and a rough feeling appears, which is not preferable. Therefore, more preferably 160 g or less, most preferably 12 g or less.
It is good to be 0 g or less.

The moisture permeability of this nonwoven fabric is 100 g / m ² /
hr or more is preferable. The moisture permeability indicates the performance of dissipating moisture, and the larger the value, the better the performance. Moisture permeability 100 g / m ² / hr
If it is less than this, it will be difficult for moisture to diffuse, so when used as clothing or house wrap, it will be filled with moisture and eventually dew condensation will occur, causing discomfort or generating mold and causing unsanitary I do. Therefore, the higher the numerical value, the better the moisture permeability.

The basis weight of this nonwoven fabric is 50
Although 0 g / m ² is possible, usually 20 to 200 g / m ²
m ² applies. The method for producing the nonwoven fabric will be described below. In order to manufacture this nonwoven fabric, first, fibers having a network structure constituting the nonwoven fabric must be manufactured. In manufacturing the fibers having the network structure, the above-described flash spinning method is applied.

When the mixed solution for spinning is spun from the nozzle, the flash stream and the precipitated fibers collide with the rotating plate, and the fibers having a network structure are traversed. The process of forming the fibers having the network structure is as described above. As the fiber opening method, there are a friction charging method using a rotating plate and a method using a subsequent corona discharge, and either method may be used or both may be used.

After the fibrous web thus opened is deposited on a conveyor to form a fibrous web, the fibrous web is partially pressed using an embossing machine. The embossing machine includes a hot embossing machine and a pin sonic machine using ultrasonic waves.

As the thermocompression bonding conditions in the case of the hot embossing machine, the temperature conditions are set to a melting point minus 40 ° C. or more and a melting point of the polymer having the lowest melting point among the polymers constituting the fibers, It is preferable to select a linear pressure condition of 0.5 kg / cm or more and 50 kg / cm or less. It should be noted that the processing may be performed with a clearance of 0.02 mm to 0.2 mm under the condition of applying the linear pressure in this range. The clearance is taken in order to prevent the crimping point from completely fusing and forming a film, and it may be properly used according to the intended use. In addition, it is preferable to perform embossing under the above-mentioned conditions after preliminarily pre-compression bonding with a roll at room temperature because the fibril fiber web does not disturb. If thermocompression bonding is performed at a temperature higher than the melting point of the polymer during embossing, the fibers may be melted, and the web may be taken up by the roller, making it impossible to form a sheet. Further, the fibers having an extremely fine network structure are fused, and the effect of obtaining the ultrafine fibril fibers is reduced. On the other hand, when a temperature lower than the melting point of the polymer minus 40 ° C. is finally applied, the adhesiveness between the fibers is reduced, and the strength of the nonwoven fabric is undesirably reduced.

On the other hand, if the linear pressure is less than 0.5 kg / cm, the adhesiveness at the crimping point between the fibers decreases, and the strength of the nonwoven fabric decreases, which is not preferable. On the other hand, if it exceeds 50 kg / cm, the crimping point tends to be formed into a film, and if it exceeds that, a nonwoven fabric with holes is formed, which is not preferable.

The crimping conditions in the case of the pin sonic processing machine may be such that the fibers are partially fused by, for example, ultrasonic vibration of about 20 kHz so that the nonwoven fabric is maintained.
The degree of fusion may be arbitrarily selected by changing the amplitude of the ultrasonic wave. If this ultrasonic fusion method is applied,
When the web having a large heat-fusibility is bonded, the web is hardly affected by heat except for the bonded portion, so that the nonwoven fabric as a whole is maintained while maintaining the heat shrinkability. For this reason, when producing a nonwoven fabric having high heat shrinkability, the effect is further exhibited.

The embossing form of these embossing machines is generally formed by an engraving roll having a projecting pattern and a flat roll. The projecting pattern can be constituted by mainly controlling the above-mentioned bonding area ratio and bonding point density.
Any shape such as a round shape, an elliptical shape, a rhombic shape, a triangular shape, a triangular shape, a T shape, a negative shape, a well shape, or a lattice shape can be adopted as the tip end surface shape of these engraving rolls.

It is to be noted that another embossing may be performed before or after embossing under another condition or under the above-mentioned conditions without departing from the scope of the present invention. Good.

[0060]

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

Melting point of polymer: using a "Differential Scanning Calorimeter DSC-2" manufactured by PerkinElmer Co., Ltd. at a heating rate of 20.degree.
The temperature at which the extreme value of the melting absorption curve measured in / min was given was taken as the melting point.

Fiber fineness: A positive fineness was determined according to JIS L-1090. Specific surface area; "BELSORP2" manufactured by Nippon Bell Co., Ltd.
Using "8", the specific surface area of the fiber was measured by the BET nitrogen adsorption method, and determined in m ² / g.

Dyeing property: After performing the following dispersion dyeing or cationic dyeing, reduction dyeing was carried out, and after washing with water and drying, the dyeing property of the fiber was evaluated as follows.

◎ Very good, ○ Good, △ Somewhat good, × Poor Disperse dyeing: 1% o of disperse dye Blue E-FBL (manufactured by Sumitomo Chemical)
wf, 1 g / l of a dispersant Disper-TL (manufactured by Meisei Chemical Co., Ltd.) and 0.1 g / l of formic acid as an auxiliary agent were prepared, and the mixture was subjected to boiling dyeing for 60 minutes at a bath ratio of 1:50.

Cationic dyeing: Cationic dye “Astrazon B
lue FFR (manufactured by Bayer) 1% owf, leveling agent "Miggle Girl WA-10 (manufactured by Senka)" 0.5 g / l, and sodium sulfate 10% owf as an auxiliary agent were prepared. : 50 for 60 minutes.

Reduction dyeing: "Sunmol RL" as a scouring agent
-100 (manufactured by Nikka Chemical Co., Ltd.), 1 g / l of hydrosulfite, and 1 g / l of caustic soda were prepared at a bath ratio of 1:50 and treated at 80 ° C. for 20 minutes.

KS strength and tensile elongation of non-woven fabric: "Tensilon UTM-4-1-10" manufactured by Toyo Baldwin Co., Ltd.
According to the strip method described in JIS L-1096, ten 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 tensile speed of 10 cm / min. In each case, the maximum tensile strength was averaged, and a value converted to 100 g / m ² was defined as the KS strength. The maximum elongation at that time was averaged to obtain the tensile elongation of the nonwoven fabric.

Apparent density of nonwoven fabric: A total of five specimens each having a specimen width of 10 cm and a specimen length of 10 cm were prepared, and the basis weight was measured for each specimen. Then, using a thickness measuring instrument manufactured by Daiei Kagaku Seiki Seisaku-sho, Ltd. A 4.5 g / cm ² load was applied, the thickness was measured after standing for 10 seconds, the apparent density was calculated by the following equation, and the average value was defined as the apparent density of the nonwoven fabric.

Apparent density (g / cm ³ ) = basis weight (g / m ² ) / thickness (mm) / 1000 Moisture permeability of nonwoven fabric; temperature 40 ° C., humidity 90% according to JIS-L 1099-A-1 Under the condition of (g / m
² / hr). Example 1 600 g of high-density polyethylene having a melting point of 132 ° C., a density of 0.96 g / cm ³ and a melt index of 0.8 g / 10 min, a melting point of 256 ° C. and a relative viscosity in a 10 liter autoclave ηrel is 1.
The autoclave was charged with 900 g of polyethylene terephthalate of No. 7 and methylene chloride as a solvent. Further, lauryl ether to which 3 mol of polyoxyethylene was added and isotridecyl stearate were added as surfactants in an amount of 0.2% by weight based on the mixed polymer. Then close the autoclave and continue
Nitrogen was injected into the autoclave until the pressure reached 20 kg / cm ² , stirring was started at an appropriate speed, and heating was started. As for the solution concentration of each component, the concentration of the polymer was 20% by weight and the concentration of the solvent was 80% by weight.

The time from when the temperature reached 100 ° C. to when the temperature reached 220 ° C. was 40 minutes. After the temperature reached 220 ° C., stirring was continued for 10 minutes to obtain a homogeneous solution. The pressure at this time showed a gauge pressure of 109 kg / cm ² . Next, while the autoclave was pressurized to 110 kg / cm ² by a continuous high-pressure nitrogen gas injection device,
Immediately, three valves were opened, and spinning was performed from three nozzles having a pressure drop chamber with a hole diameter of 0.75φ and L / D = 1. This was made to collide with a rotating plate, then spread, and deposited on a moving conveyor net to form a web. The pressure in the pressure drop chamber was 92 kg / cm ² .

Next, the web was laminated and passed through a hydraulic clearance calender having three pairs of rollers to produce a nonwoven fabric having a basis weight of 50 g / m ² . The upper rollers of this calender are all made of urethane rubber,
The lower roller was a heating roller having a steel surface coated with a fluororesin. The temperature and linear pressure from the first roller to the third roller are 60, respectively.
120, 125 ° C, 0.3, 0.8, 1.5 kg / cm.

The obtained nonwoven fabric has a very good fibril state of the fibers, no coloring, and the fibers are adhered over the entire surface. Therefore, the strength of the nonwoven fabric is high, and the moisture permeability and water pressure resistance are high. Was also expensive. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of this nonwoven fabric were as follows.

Specific surface area: 31 m ² / g Non-woven fabric KS strength (MD / CD): 38.4 / 39.8 kg / 5 cm Non-woven fabric elongation (MD / CD): 18/26% Apparent density: 0.40 g / cm ³ Moisture permeability: 280 g / m ² / hr Water pressure: 180 cmH ₂ O Dyeability: 〔[Example 2] Using the same apparatus as in Example 1, melting point 162
C., 400 g of polypropylene having a density of 0.910 g / cm ³ and a melt flow rate of 4 g / 10 min, 1100 g of polyethylene terephthalate having a melting point of 256 ° C. and a relative viscosity ηrel of 1.6, and methylene chloride as a solvent. And in an autoclave. Further, lauryl ether to which 3 mol of polyoxyethylene was added and isooctyl laurate were added as surfactants in an amount of 0.2% by weight based on the mixed polymer. After closing the autoclave, nitrogen was injected into the autoclave until the pressure became 40 kg / cm ² , stirring was started at an appropriate speed, and heating was started. The concentration of the mixed polymer in the solution was 20% by weight, and the concentration of the solvent was 80% by weight.

The time from when the temperature reached 100 ° C. to when the temperature reached 200 ° C. was 30 minutes. After the temperature reached 200 ° C., stirring was carried out for 10 minutes to obtain a uniform solution. The pressure at this time showed a gauge pressure of 118 kg / cm ² . Next, while the autoclave was pressurized to 120 kg / cm ² by a continuous high-pressure nitrogen gas injection device,
Immediately, three valves were opened, and spinning was performed from three nozzles having a pressure drop chamber with a hole diameter of 0.75φ and L / D = 1. This was made to collide with a rotating plate, then spread, and deposited on a moving conveyor net to form a web. The pressure in the pressure drop chamber was 99 kg / cm ² . Next, the webs were laminated, and the temperatures from the first roller to the third roller in the calender were increased to 60 ° C., 150 ° C., and 1 ° C., respectively.
The same as in Example 1 except that the temperature was changed to 55 ° C.
A non-woven fabric of 0 g / m ² was produced.

The obtained non-woven fabric has a very good fibril state of the fiber, no coloring, and has a structure in which the fiber is adhered to the entire surface, so that the non-woven fabric has high strength, moisture permeability, and water pressure resistance. Was also expensive. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of the obtained nonwoven fabric were as follows.

Specific surface area: 29 m ² / g Non-woven fabric KS strength (MD / CD): 32.3 / 33.6 kg / 5 cm Non-woven fabric elongation (MD / CD): 22/29% Apparent density: 0.47 g / cm ³ Moisture permeability: 263 g / m ² / hr Water pressure: 159 cmH ₂ O Dyeability: ◎ [Example 3] Melting point: 247 ° C., relative viscosity ηrel: 1.3
Using polyethylene terephthalate copolymerized with 5 mol% of sulfoisophthalic acid,
A nonwoven fabric was manufactured under the same conditions as in Example 2 except that the temperature was set to 00 ° C. The pressure during dissolution was 119 kg / cm ² , and the pressure in the descending chamber was 100 kg / cm ² .

The obtained nonwoven fabric has a very good fibril state of the fibers, no coloring, and the fibers are adhered over the entire surface, so that the nonwoven fabric has high strength, moisture permeability and water pressure resistance. It was expensive. When this nonwoven fabric was dyed using a cationic dye, it was confirmed that the nonwoven fabric could be dyed clearly. The properties of this nonwoven fabric are
It was as follows.

Specific surface area: 28 m ² / g Non-woven fabric KS strength (MD / CD): 29.2 / 30.1 kg / 5 cm Non-woven fabric elongation (MD / CD): 17/25% Apparent density: 0.39 g / cm ³ Moisture permeability: 278 g / m ² / hr Water pressure: 172 cmH ₂ O Dyeability: ◎ [Example 4-8 Comparative Examples 1 and 2] Using the apparatus of Example 1, melting point 132 ° C., density A high-density polyethylene having 0.96 g / cm ³ and a melt index value of 0.6 g / 10 min, a melting point of 256 ° C. and a relative viscosity ηrel of 1.4;
The amount of methylene chloride as the solvent was changed to 6200 g while changing the mixing ratio with polyethylene terephthalate, which was
Autoclave was filled as constant. As a surfactant, lauryl ether to which 3 mol of polyoxyethylene was added and isooctyl laurate were added in an amount of 0.2% by weight based on the mixed polymer, and the autoclave was closed. Subsequently, nitrogen was injected into the autoclave so as to be 40 kg / cm ² , and stirring was started at an appropriate speed and heating was started.

The solution concentration of each component is as shown in Table 1, and the time from when the temperature reaches 100 ° C. to when the temperature reaches 200 ° C. is 3 hours.
It was 5 minutes, and stirring was continued for 10 minutes after the temperature reached 200 ° C. to obtain a homogeneous solution. The pressure at this time is approximately 11
The gauge pressure was 0 kg / cm ² . Next, the pressure in the autoclave was set to 110 by a continuous high-pressure nitrogen gas injection device.
While passing the pressure so as to be maintained at kg / cm ² , three valves were immediately opened to carry out spinning, and a web was formed in the same manner as in Example 1 to obtain a nonwoven fabric.

Table 1 shows the results.

[0081]

[Table 1] As is clear from Table 1, in Example 4-8, as the mixing ratio of the polyester increased, the dyeability with the disperse dye also tended to be good, and the obtained nonwoven fabric had a very good fibril fiber state. And there was no coloring. In addition, since these fibers are bonded over the entire surface, the strength of the nonwoven fabric is high, and the moisture permeability and the water pressure resistance are high.

In Comparative Example 1, the obtained nonwoven fabric had a good fibril state and a relatively high nonwoven fabric strength, but had no dyeability because it did not contain any polyester.

In Comparative Example 2, polyethylene was completely used.
Because it does not contain, the obtained nonwoven fabric is based on disperse dye
Stainability was good, but fibril condition was too good
With strong nonwoven fabric, low moisture permeability and low water pressure
there were. Example 9 Melting point: 228 ° C. and relative viscosity ηrel: 1.
7 using polybutylene terephthalate
And the spinning temperature was 200 ° C, except that the spinning temperature was 200 ° C.
A non-woven fabric was manufactured. The pressure during dissolution is 112kg / cm
^Two , The pressure in the descending chamber is 93kg / cm ^Two Met.

The obtained nonwoven fabric has a very good fibril state of the fibers, no coloring, and the fibers are bonded over the entire surface, so that the nonwoven fabric has high strength, moisture permeability and water pressure resistance. It was expensive. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of this nonwoven fabric were as follows.

Specific surface area: 31 m ² / g Non-woven fabric KS strength (MD / CD): 36.3 / 37.4 kg / 5 cm Non-woven fabric elongation (MD / CD): 21/29% Apparent density: 0.37 g / cm ³ Moisture permeability: 292 g / m ² / hr Water pressure: 191 cmH ₂ O Dyeability: ◎ [Example 10] Using a 10 liter autoclave,
600 g of high-density polyethylene having a melting point of 132 ° C., a density of 0.96 g / cm ³ , and a melt index value of 0.8 g / 10 minutes; 900 g of polyethylene terephthalate having a melting point of 256 ° C. and a relative viscosity ηrel of 1.7;
The autoclave was charged with methylene chloride as a solvent. In addition, isooctyl stearate and isostearyl ester were added as surfactants in an amount of 0.2% by weight based on the mixed polymer. The autoclave was closed, nitrogen was subsequently injected into the autoclave so as to be 20 kg / cm ² , stirring was started at an appropriate speed, and heating was started. The solution concentration of each component was 20% by weight of the polymer and 80% by weight of the solvent.

The time from when the temperature reached 100 ° C. to when the temperature reached 220 ° C. was 40 minutes. After the temperature reached 220 ° C., stirring was continued for 10 minutes to obtain a homogeneous solution. The pressure at this time showed a gauge pressure of 109 kg / cm ² . Next, while the autoclave was pressurized to 110 kg / cm ² by a continuous high-pressure nitrogen gas injection device,
Immediately, three valves were opened, and spinning was performed from three nozzles having a pressure drop chamber with a hole diameter of 0.75φ and L / D = 1. This was made to collide with a rotating plate, then spread, and deposited on a moving conveyor net to form a web. In addition,
The pressure in the pressure drop chamber was 92 kg / cm ² .

[0087] Next laminating this web, through a hydraulic clearance embossing machine to produce a basis weight 50 g / m ² non-woven fabric. The upper roll of this embossing machine was an engraving roll, the lower roll was a flat roll, and both were heating rolls. No clearance between the upper and lower rolls, linear pressure 20 kg / cm, temperature 125 ° C, speed 1
Embossing was performed at 0 m / min. The adhesion area ratio of the engraving roll was 25%, and the adhesion point density was 60 pieces / cm ² .

The obtained nonwoven fabric had a very good fibril state of the fiber, and no coloring was observed. Moreover, this fiber has a configuration in which many small crimping points are present, and thus has excellent flexibility and moisture permeability while maintaining practical nonwoven fabric strength. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of this nonwoven fabric were as follows.

Specific surface area: 31 m ² / g Non-woven fabric KS strength (MD / CD): 17.3 / 18.6 kg / 5 cm Non-woven fabric tensile elongation (MD / CD): 28/31% Apparent density: 0. 28 g / cm ³ Compression stiffness: 125 g Moisture permeability: 250 g / m ² / hr Dyeability: ◎ [Example 11] Using the same apparatus as in Example 10, melting point 16
400 g of polypropylene having a temperature of 2 ° C., a density of 0.910 g / cm ³ , and a melt flow rate of 4 g / 10 minutes;
An autoclave was charged with 1100 g of polyethylene terephthalate having a melting point of 256 ° C. and a relative viscosity ηrel of 1.6, and methylene chloride as a solvent. In addition, isooctyl stearate and isostearyl ester were added as surfactants in an amount of 0.2% by weight based on the mixed polymer. Close the autoclave and subsequently inject nitrogen into the autoclave until 40 kg / cm ²
Stirring was started at an appropriate speed and heating was started. The concentration of the mixed polymer in the solution was 20% by weight, and the concentration of the solvent was 8%.
It was 0% by weight.

The time from when the temperature reached 100 ° C. to when the temperature reached 200 ° C. was 30 minutes. After the temperature reached 200 ° C., stirring was carried out for 10 minutes to obtain a homogeneous solution. The pressure at this time showed a gauge pressure of 118 kg / cm ² . Next, while the autoclave was pressurized to 120 kg / cm ² by a continuous high-pressure nitrogen gas injection device,
Immediately, three valves were opened, and spinning was performed from three nozzles having a pressure drop chamber with a hole diameter of 0.75φ and L / D = 1. This was made to collide with a rotating plate, then spread, and deposited on a moving conveyor net to form a web. The pressure in the pressure drop chamber was 99 kg / cm ² . Next, this web was laminated, and a nonwoven fabric having a basis weight of 100 g / m ² was produced in the same manner as in Example 10 except that the temperature of the embossing was set to 120 ° C.

The obtained nonwoven fabric has a very good fibril state of the fiber, no coloration is observed, and since the fiber has a structure in which many small crimping points are present, practical nonwoven fabric strength is maintained. Moreover, it was excellent in flexibility and moisture permeability. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of this nonwoven fabric were as follows.

[0092] The specific surface area: 29 m ² / g nonwoven KS strong (MD / CD): 16.2 / 17.7 kg / 5cm nonwoven tensile elongation (MD / CD): 30/33% apparent density: 0. 29 g / cm ³ Compression hardness: 120 g Moisture permeability: 231 g / m ² / hr Dyeing property: ： [Example 12] Melting point: 247 ° C., relative viscosity ηrel: 1.
Using polyethylene terephthalate copolymerized with 5 mol% of sulfoisophthalic acid, which is 3, the melting and spinning temperature is 20
A nonwoven fabric was produced under the same conditions as in Example 20 except that the temperature was set to 0 ° C. The pressure during melting was 119 kg / cm ² , and the pressure in the descending chamber was 100 kg / cm ² .

The obtained nonwoven fabric has a very good fibril state of the fiber, no coloring is observed, and the fiber has a structure in which many small crimping points are present. Moreover, it was excellent in flexibility and moisture permeability. When this nonwoven fabric was dyed using a cationic dye, it was confirmed that the nonwoven fabric could be dyed clearly.
The characteristics of this nonwoven fabric were as follows.

Specific surface area: 28 m ² / g Non-woven fabric KS strength (MD / CD): 14.5 / 15.7 kg / 5 cm Non-woven fabric tensile elongation (MD / CD): 37/39% Apparent density: 0. 30 g / cm ³ compression stiffness: 118 g breathable: 247 g / m ² / hr dyeability: ◎ using the apparatus of example 13-17 Comparative examples 3 and 4] example 10, melting point 132 ° C., While changing the mixing ratio of high-density polyethylene having a density of 0.96 g / cm ³ and a melt index value of 0.6 g / 10 min, and polyethylene terephthalate having a melting point of 256 ° C. and a relative viscosity ηrel of 1.4. , The amount of methylene chloride as a solvent is 62
The autoclave was filled to a constant volume of 00 g. Isooctyl stearate and isostearyl ester were added as surfactants in an amount of 0.2% by weight based on the mixed polymer, and the autoclave was closed. Subsequently, nitrogen was injected into the autoclave so as to be 40 kg / cm ² ,
Stirring was started at an appropriate speed and heating was started.

The solution concentration of each component is as shown in Table 2. The time from when the temperature reached 100 ° C. to when the temperature reached 200 ° C. was 35 minutes. After the temperature reached 200 ° C., stirring was continued for 10 minutes. A homogeneous solution was obtained. The pressure at this time showed a gauge pressure of about 110 kg / cm ² . Next, three valves were immediately opened and spinning was performed by using a continuous high-pressure nitrogen gas injecting device so that the pressure in the autoclave was maintained at 110 kg / cm ^2. Thus, a web was formed and a nonwoven fabric was obtained.

Table 2 shows the results.

[0097]

[Table 2] As is clear from Table 2, in Examples 13 to 17, the dyeability with the disperse dye tends to be improved as the mixing ratio of the polyester increases, and the obtained nonwoven fabric has an extremely good fibril fiber state. It is not colored, and because this fiber has a structure with many small crimp points, while maintaining practical nonwoven fabric strength,
It was excellent in flexibility and moisture permeability. In addition, when these nonwoven fabrics were dyed using a disperse dye, it was confirmed that clear dyeing was possible.

In Comparative Example 3, the obtained nonwoven fabric had a good fibril state and a relatively high strength of the nonwoven fabric. However, since it did not contain any polyester, the dyeability was quite poor.

In Comparative Example 4, since no polyethylene was contained, the obtained nonwoven fabric had good dyeability with a disperse dye, but the fibril state was not so good, and both the strength and the moisture permeability of the nonwoven fabric were low. Was something. Example 18 A nonwoven fabric was produced under the same conditions as in Example 15 except that polybutylene terephthalate having a melting point of 228 ° C. and a relative viscosity η rel of 1.7 was used and the melting and spinning temperature was 200 ° C. Melting pressure is 112kg
/ Cm ² and the pressure in the descending chamber was 93 kg / cm ² .

The obtained nonwoven fabric has a very good fibril state of the fiber, no coloration is observed, and since this fiber has a structure in which many small pressure-bonding points are present, it is possible to maintain a practical nonwoven fabric strength. , Flexibility and moisture permeability. When this nonwoven fabric was dyed with a disperse dye, it was confirmed that the nonwoven fabric could be dyed clearly. The characteristics of this nonwoven fabric were as follows.

Specific surface area: 31 m ² / g Non-woven fabric KS strength (MD / CD): 15.3 / 16.5 kg / 5 cm Non-woven fabric tensile elongation (MD / CD): 37/39% Apparent density: 0. 27 g / cm ³ Compression stiffness: 109 g Moisture permeability: 262 g / m ² / hr Dyeing property: 実 施 (Examples 19 to 25) When manufacturing the nonwoven fabric of Example 16, the type of the embossing roll was changed. Then, as shown in Table 3, the bonding area ratio and the bonding point density were changed. Table 3 shows the results.

[0102]

[Table 3] As is evident from Table 3, the nonwoven fabrics of Examples 19 to 24 maintain practical nonwoven fabric strength while the strength of the nonwoven fabric tends to increase and the flexibility tends to decrease as the bonding area ratio and the bonding point density increase. In addition, it was excellent in flexibility and moisture permeability.

In Example 25, since the bonding area ratio was 100% due to pressure bonding using only a flat roll, the obtained nonwoven fabric was slightly inferior in flexibility, but practical nonwoven fabric strength and excellent moisture permeability were obtained. It was equipped.

[0104]

As described above, according to the present invention, there is provided a non-woven fabric constituted by fibril fibers having a network structure, wherein the fibers are obtained by a flash spinning method and are not compatible with each other. First consisting of a polymer component
Of fibril fiber and ester-based polymer component
And the fibril fibers are present in a mixed state, and the mixing ratio between the olefin polymer component and the ester polymer component is in the range of 5/95 to 95/5 by weight, and the nonwoven fabric is Since the fibril fibers having the network structure are bonded over the whole or partially bonded, it is possible to obtain a nonwoven fabric having a dense structure composed of highly fibrillated ultrafine fibers. .

 ──────────────────────────────────────────────────の Continuing from the front page (72) Inventor Koichi Nagaoka 23 Uji Kozakura, Uji-city, Kyoto Unitika Inside the Central Research Laboratory, Ltd. (72) Inventor Hiroshi Nishimura 23 Uji Kozakura, Uji-shi, Kyoto Unitika Central Research, Ltd. In-house F-term (reference) 4L035 AA04 BB42 FF05 LA01 4L047 AA14 AA21 AA27 AB08 AB09 BA09 BA22 CA12 CB01 CB08 CB10 CC02 CC04 CC05 CC10 CC12

Claims (12)

[Claims] 1. A nonwoven fabric having a dense structure, which is composed of a fibril fiber having a network structure, wherein the fiber is obtained by a flash spinning method and is an olefin polymer component having no compatibility with each other. And the second fibril fiber composed of an ester-based polymer component are present in a mixed state, and the mixing ratio of the olefin polymer component to the ester-based polymer component is A ratio of 5/95 to 95/5 in a ratio, wherein the non-woven fabric is formed of fibers having a network structure, wherein fibril fibers having the network structure are bonded to each other. 2. The olefin polymer component is any one of an ethylene polymer, a propylene polymer, a copolymer mainly composed of ethylene, and a copolymer mainly composed of propylene. A nonwoven fabric comprising the fibers having a network structure according to claim 1. 3. The nonwoven fabric comprising fibers having a network structure according to claim 1, wherein the ester-based polymer component is one of polyethylene terephthalate and polybutylene terephthalate. 4. The mixing ratio of the olefin polymer to the ester polymer in the mixture is from 15/85 to 8 by weight.
4. The range of 5/15.
A nonwoven fabric comprising the fibers having a network structure according to any one of the above. 5. The network fibers are adhered to each other throughout, and the nonwoven fabric has a strength of at least 20 kg / 5 cm, a water pressure resistance of at least 50 cm, and a moisture permeability of 100 g / m 2.
^The nonwoven fabric made of a fiber having a network structure according to any one of claims 1 to 4, wherein the nonwoven fabric is not less than ² / hr. 6. The inter-network fibers are partially bonded is, as the nonwoven fabric performance, tenacity 5 kg / 5 cm or more, the compression stiffness is 200g or less, and moisture permeability 100 g / m ² /
The nonwoven fabric made of a fiber having a network structure according to any one of claims 1 to 4, wherein the nonwoven fabric has a length of not less than hr. 7. A method for producing a nonwoven fabric having a dense structure, comprising mixing a mixed polymer of an olefin polymer and an ester polymer which are not compatible with each other with an olefin polymer and an ester polymer. Under a solvent, the mixture is dissolved under a high temperature and a high pressure so as to have a mixing ratio of 5/95 to 95/5 by weight, thereby forming a single bath phase. A fibril having a network structure in which a first fibril fiber composed of an olefin-based polymer component and a second fibril fiber composed of an ester-based polymer component are mixed and spun out of a nozzle in a separated state. Make fiber,
A method for producing a nonwoven fabric made of fibers having a network structure, wherein the fibers are formed into a web, and then the web is thermocompression-bonded using a group of rolls to bond the fibril fibers having a network structure entirely. 8. The temperature at which the web is thermocompression-bonded using the roll group is set to a temperature exceeding the melting point of the polymer component having the lowest melting point among the polymer components constituting the fiber minus 40 ° C. and not more than the melting point. Range, and the linear pressure during thermocompression bonding is 0.5
The method for producing a non-woven fabric comprising fibers having a network structure according to claim 7, wherein the non-woven fabric is in a range of not less than kg / cm and not more than 20 kg / cm. 9. A method for producing a nonwoven fabric having a dense structure, comprising mixing a mixed polymer of an olefin polymer and an ester polymer which are not compatible with each other with an olefin polymer and an ester polymer. Under a solvent, the mixture is dissolved under a high temperature and a high pressure so as to have a mixing ratio of 5/95 to 95/5 by weight, thereby forming a single bath phase. A fibril having a network structure in which a first fibril fiber composed of an olefin-based polymer component and a second fibril fiber composed of an ester-based polymer component are mixed and spun out of a nozzle in a separated state. Make fiber,
This fiber is made into a web, and thereafter, the web is partially thermocompression-bonded using an embossing machine, and a non-woven fabric made of a fiber having a network structure characterized by partially bonding between fibril fibers having a network structure. Production method. 10. The temperature at which the web is thermocompression-bonded using an embossing machine is set to exceed the melting point of the polymer component having the lowest melting point among the polymer components constituting the fiber minus 40 ° C. and not more than the melting point. 10. The method for producing a nonwoven fabric made of fibers having a network structure according to claim 9, wherein the linear pressure at the time of thermocompression bonding is within a range of 0.5 kg / cm or more and 50 kg / cm or less. 11. The fiber having a network structure according to claim 9 or 10, wherein a bonding area ratio when partially bonding the fibril fibers having a network structure is 4% or more and 50% or less. Manufacturing method of nonwoven fabric. 12. The bonding point density when fibril fibers having a network structure are partially bonded to each other is not less than 15 pieces / cm ² and 1
The method for producing a non-woven fabric comprising fibers having a network structure according to any one of claims 9 to 11, wherein the number is set to 20 / cm ² or less.