JP2783411B2 - High strength wet nonwoven fabric and method for producing the same - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a high-strength wet nonwoven fabric and a method for producing the same.

[Conventional technology]

In recent years, nonwoven fabrics have been used in alternative applications such as conventional knitted fabrics or functional applications that cannot be handled by knitted fabrics and the like, utilizing their excellent performance and high productivity characteristics, and have shown remarkable development. Various types of nonwoven fabrics are known, but typical ones are a spunbond method disclosed in JP-B-48-38025 and the like, a flash spinning method disclosed in JP-B-42-19520 and the like. A long-fiber dry nonwoven fabric obtained by directly spinning the fiber-forming polymer of the present invention and simultaneously pulling and accumulating the filaments with air, gas, etc., JP-A-49-489
21 Short fiber dry non-woven fabric with relatively long fiber length obtained by melt blowing method disclosed in 21 etc., after carding short fibers, cross layer, sheeting with air layer etc. by needle punch or columnar water flow according to purpose There are known short-fiber dry nonwoven fabrics obtained by confounding or bonding with adhesives, heat-fusible fibers, etc., and wet nonwoven fabrics obtained by a papermaking method.

Long-fiber dry nonwoven fabrics obtained by spunbonding, flash spinning, etc. are characterized by high strength such as tensile strength and tear strength because the constituent fibers of the nonwoven fabric are filaments. Widely used for industrial materials that require high strength.

However, among the strengths, the nonwoven fabric delamination strength is at most 300 to 400 g / cm, which is not a sufficient strength. This is presumed to be due to the fact that the constituent fibers are long fibers, and that the joining of the fibers is only performed by thermocompression bonding, which is two-dimensional, and that there is almost no entanglement between the single fibers. Is done. Also,
In these nonwoven fabrics, the sheet forming method relies on traction and accumulation by air flow, gas flow, etc., so that the sheet is inevitably uniform, that is, there is a large unevenness in the weight, and the filament bonding means is generally thermocompression bonded, so that the elongation is increased. There was a drawback that it was hard and lacked drapability. In addition, short fiber dry nonwoven fabrics obtained by bonding sheets formed by the card method with needle punches or heat-fused adhesive fibers are inferior in strength due to the shorter fiber length compared to long fiber dry nonwoven fabrics. In many cases, the constituent fibers are joined with an adhesive or the like to compensate, and in this case, there is a disadvantage that the feel is hard.

The so-called spunlace type nonwoven fabric of no binder obtained by entanglement of the sheet formed by the card method disclosed in JP-A-48-13749 and the like with a columnar water stream is bonded with a spun bond, an adhesive, and a heat fusion fiber. Compared to the dry method non-woven fabric made by the card method, it is superior in terms of soft feeling, but also because the sheet is formed by the dry method, uniformity (eye spots)
And the delamination strength is still insufficient.

On the other hand, a wet nonwoven fabric has a feature that it is incomparably better than a dry nonwoven fabric because a very short fiber is dispersed in water to form a sheet. However,
In order to disperse the fibers uniformly in water, the fiber length is generally 3
Since an extremely short length of about 7 mm is required, the nonwoven fabric obtained by this method has extremely low strength, and its use is limited to fields where little strength is required. Further, in the papermaking method, since wet pressing is usually performed by pressing with a felt or a Yankee dryer, the wet nonwoven fabric generally has a disadvantage that the thickness is high, the density is high, and the paper-like feeling is inevitably obtained.

As described above, conventional nonwoven fabrics have characteristics and disadvantages in accordance with the characteristics of the manufacturing method, and there is still no nonwoven fabric having characteristics of excellent uniformity, high strength, and soft feeling. there were.

[Problems to be solved by the invention]

The present invention provides a novel wet nonwoven fabric and a method for producing the wet nonwoven fabric, in which the strength, which is a drawback, is improved while utilizing the characteristics such as excellent uniformity of the wet nonwoven fabric, and the feeling is paper-like. The purpose is to do.

[Means for solving the problem]

The present inventors have earnestly studied the above problems and arrived at the present invention. That is, the above-mentioned purpose is that the diameter of the single yarn is 7 to
Short fibers having a length of 17 μm, a fiber length of 20 mm or less, and a ratio L / D of the fiber length L to the yarn diameter D of 0.8 × 10 ^{3 to} 2.0 × 10 ³ are three-dimensionally entangled with each other. 150 μm between confounding points
m or less and a high-strength wet nonwoven fabric having a delamination strength of 1.0 kg / cm or more.

The high-strength wet nonwoven fabric according to the present invention has a single yarn diameter of 7 to 17 μm, a fiber length of 20 mm or less, and a ratio L / D of the fiber length L to the single yarn diameter D of 0.8 × 10 ^{3 to} 2.0 ×. A sheet is formed from 10 ³ short fibers by a papermaking method, and then the short fibers are three-dimensionally entangled with each other by high-speed fluid flow treatment until the average fiber entanglement distance is 150 μm or less and the delamination strength is 1.0 kg / cm or more. It can be prepared by a method for producing a high-strength wet nonwoven fabric, which is characterized in that:

The wet nonwoven fabric of the present invention is composed of short fibers having a specific shape, and it is an essential requirement that the short fibers are entangled at a specified entanglement density. A high-strength nonwoven fabric that has never been obtained is obtained.

First, it is necessary for the constituent yarn to satisfy both of the two factors of a single yarn diameter of 7 to 25 μm and a ratio L / D of the fiber length L to the single yarn diameter D of 0.8 × 10 ^{3 to} 2.0 × 10 ^3. . If the single yarn diameter is less than 7 μm, even if the L / D is within the above range, the single yarn strength is so low that the tensile strength, the tear strength, and the strength such as the delamination strength are low. Can not achieve the purpose.

If the single yarn diameter exceeds 25 μm, even if the L / D is within the range of the present invention, the fibers are too thick, so that the uniformity of the surface of the nonwoven fabric,
The fineness is lost and the object of the present invention cannot be achieved. Therefore, the single yarn diameter is 7 in terms of strength and uniformity.
2525 μm, and the preferred range is
It is 10 to 17 μm.

Next, the L / D of the yarn is 0.8 × 10 ³ within the range of the fiber diameter.
~ 2.0 × 10 ³ , the preferred range is 1.0
× 10 ^{3 to} 1.5 × 10 ³ . The L / D of the original yarn has been found by the present inventors to have an important relationship with the ease of entanglement between fibers, and when the L / D is less than 0.8 × 10 ³ and 2.0 × 10 3 If it exceeds ³ , the desired nonwoven fabric strength cannot be obtained in any case, and practical high strength can be obtained only in the range of 0.8 × 10 ^{3 to} 2.0 × 10 ³ of the present invention. This surprising fact is presumed as follows. That is, the easiness of movement of the fiber due to the columnar water flow or the like is small as L / D is small, that is, the fiber is thick and short, and the entanglement between fibers is large. On the other hand, the number of points of mutual contact between the fibers increases as the fibers are thinner and longer, that is, as the L / D is larger. However, if the L / D is too large, the movement of the fibers during the entanglement is suppressed, and the entanglement between the fibers becomes smaller. Therefore, it is understood that there is an L / D in the optimum range in which the entanglement density between the fibers is maximum, and this range is from 0.8 × 10 ^{3 to} 2.0 × 10 ³ .

In connection with the above-mentioned optimal range of L / D, if the fiber length is too long, when forming a fiber sheet by a papermaking method,
The fibers tend to become entangled in the papermaking liquid and hinder the preparation of a uniform sheet without spots, and the free movement of short fibers in the bending direction tends to be suppressed in high-speed fluid flow treatment. As shown in Examples below, by preparing a predetermined sheet by using short fibers having a fiber length of 20 mm or less, a solid wet nonwoven fabric having a structure in which the distance between the fiber entanglement points is 150 μm or less was obtained. .

The requirements for constituting the high-strength wet nonwoven fabric of the present invention are that the fiber diameter specified above is composed of short fibers having an L / D, and that such a yarn has an average fiber entanglement distance of 150 μm.
It must be composed of two points that are three-dimensionally entangled with each other in the following state. Even when the wet nonwoven fabric of the specific short fibers according to the present invention is used, the fibers are not entangled with each other as they are made, or even if they are entangled, the average distance between the fiber entanglement points exceeds 150 μm. A loosely entangled state is not included in the present invention because the high strength intended by the present invention cannot be obtained.

Regarding the diameter of the single yarn constituting the present invention, the cross-section of the single yarn may be circular or may be various non-circular modified cross-sections. In the case of a circular shape, the diameter of the single yarn is determined from the value obtained by directly measuring the diameter. In the case of the irregularly shaped yarn, the fineness (denier) of the single yarn is measured by a gravimetric method. Is assumed to be a circle, and is represented by an average diameter obtained by the following equation.

(Where R = diameter of single yarn (μm) ζ = density of polymer constituting the single yarn (g / cm ³ ) d = fineness of single yarn (denier) π = pi What is the distance between confounding points?
It is a value measured by the following method known as 280, and as a measure of the entanglement density between fibers, a smaller value indicates that the entanglement is denser. FIG. 1 is an enlarged schematic view of the constituent fibers when the constituent fibers in the wet nonwoven fabric are observed from the surface in a plane direction. The constituent fibers are f ₁ , f ₂ , f ₃ ..., And any two of the fibers are f ₁ , f 3
_The point at which ₂ is entangled is traced to the point at which the fiber f ₂ above at a ₁ intersects below the other fiber, and the intersected point is referred to as a ₂ . Similarly, a ₃ , a ₄ ,... Next, the straight-line horizontal distance a ₁ between the confounding points thus obtained
a ₂ , a ₂ a ₃ ,... are measured, and an average value of a large number of these measured values is obtained.

The yarn constituting the wet nonwoven fabric of the present invention is nylon 6,
Polyamide fibers such as nylon 66 and nylon 610, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, polyolefin fibers such as polypropylene and polyethylene, and regenerated cellulose fibers such as rayon are within the fiber diameter and L / D ranges of the present invention. Is preferably used. The yarn's Young's modulus is 50-700kg / m
m ² , especially preferably in the range of 50 to 500 kg / mm ² . 700 kg / yarn of mm ² more than such a high Young's modulus is greater flexural rigidity, the distance between the average fiber entangling point referred to in the present invention 150μ
In order to attain a confounding state of m or less, problems such as the necessity of a large confounding force (for example, a columnar water flow with a very high pressure) may occur.

 Since the wet nonwoven fabric of the present invention has such a configuration, the wet nonwoven fabric
If only non-woven fabric has high strength which has been difficult
For long fiber non-woven fabric such as spunbond or card method
From the relatively long and crimped short fibers thus obtained
Type non-woven fabric with entangled web entangled by columnar water flow
(For example, Du Pout's Sontara Spunlace such as
Much stronger than non-woven fabrics such as
It has peeling strength and is a characteristic of wet nonwoven fabric.
It is also small and has excellent uniformity.
Furthermore, compared to wet nonwoven fabric joined with ordinary adhesives, etc.
Fibers are bonded together only by three-dimensional confounding of fibers
It is not necessary to use any bonding means such as
It also has the characteristic that it is rich in hood and drape
It is.

As described above, the nonwoven fabric of the present invention has high strength and soft texture overcoming its drawbacks while having the uniformity which is a feature of the wet method, and further has a long-fiber nonwoven fabric such as spunbond or a spunlace type. It also has the strength of non-woven fabric delamination strength lacking in non-woven fabrics and has performance that could not be expected of conventional non-woven fabrics, so use it for applications that were difficult to apply with conventional non-woven fabrics Can be.

One of the preferable examples is a material for medical and sanitary materials, for example, a medical material such as a surgical pack, a surgical gown, and an underpad, and a sanitary material such as a diaper, a napkin, and a mask. In these applications, the characteristics of the nonwoven fabric of the present invention having rich drape property and high strength are well utilized.

In particular, when the nonwoven fabric of the present invention is used for a surgical gown, the property of being excellent in a liquid barrier property particularly required for a surgical gown is well utilized. The nonwoven fabric of the present invention has a specified L / D
Has a high liquid barrier property per se because the short fibers having a high density are entangled with each other. As an attempt to obtain a liquid barrier property required for surgical gowns with a conventional nonwoven fabric, for example, as disclosed in JP-A-59-94659, wood composed of polyester (polyethylene terephthalate) and fine fibrils is used. Laminating or mixing pulp or jetting a columnar water stream onto the obtained sheet has been devised to increase the density of the nonwoven fabric by entanglement of the pulp with polyester in a so-called "stuffing" manner, but in the present invention, It has been confirmed that excellent liquid barrier properties can be obtained simply by using a 1d, 12.5 mm yarn of polyester (polyethylene terephthalate) without using such special filling binder fibers. I have.

When the nonwoven fabric of the present invention is used for an interlining for clothing, the characteristics of uniformity and high strength are well utilized and are also preferable. It is also suitable for industrial wiping cloths such as in the electronic field. This is because the nonwoven fabric of the present invention is excellent in lint-free properties because the fibers are firmly bonded by entanglement between fibers with no binder, and is excellent in wiping properties because it is flexible. Further, it is recognized that the filter is suitable as a so-called pre-filter for filtering a gas or liquid filter, particularly for filtering particles of 5 to 25 μm. This is a result that the characteristic that the nonwoven fabric has a small average inter-fiber entanglement distance and is dense is sufficiently utilized for the filter function.

When the nonwoven fabric of the present invention is used as a coating base fabric, the characteristics of the nonwoven fabric of the present invention are well utilized. In other words, attempts have been made to use a conventional nonwoven fabric as a coating base fabric in place of the conventional woven or knitted fabric, but in the case of these nonwoven fabrics, the delamination strength is weaker than that of a woven fabric or a knitted fabric. In many cases, coated products obtained by coating polyurethane or polyvinyl chloride caused a peeling phenomenon between layers of the nonwoven fabric during use and were not practically usable. In order to remedy this drawback, an elastic polymer such as polyurethane, polyacrylate, SBR, MBR, NBR, etc. is previously applied to the nonwoven fabric as a binder, and then the surface is coated with polyurethane, polyvinyl chloride, etc. However, in this case, it was unavoidable that the texture became paper-like and the quality was inferior to that of the woven or knitted fabric. On the other hand, since the nonwoven fabric of the present invention has an extremely high delamination strength as compared with the conventional nonwoven fabric, it can be used as a coating base fabric without a binder. It has new characteristics that are excellent in feeling and high delamination strength.

The use of the nonwoven fabric of the present invention as a base fabric for artificial leather is also a preferred example. For example, use this non-woven fabric as its base fabric, and apply polyurethane, vinyl chloride,
By applying a solution or an emulsion of an elastic polymer such as SBR, NBR, MBR or the like with a gravure, a doctor knife or the like, a silver-like artificial leather can be obtained. In this case, if necessary, it is more preferable to impregnate the nonwoven fabric with an elastic polymer such as polyurethane and form it by dry or wet coagulation before filling the surface coating layer, and then to fill the nonwoven.

Furthermore, when it is desired to obtain suede-like artificial leather, a sheet made of ultrafine fibers having a single-fiber fineness of 0.5 d or less is laminated on the present nonwoven fabric, and the laminate is three-dimensionally entangled to form an integrated nonwoven fabric. It is also possible to obtain the desired suede-like artificial leather by raising the microfiber entangled layer, impregnating it with an elastic polymer or the like as necessary, or dyeing it.

Next, a method for producing the high-strength wet nonwoven fabric of the present invention will be described.

First, short fibers having a single yarn diameter of 7 to 25 μm and a specific shape of L / D 0.8 × 10 ³ to 2 × 10 ³ are prepared. 0.1 ~ 3%
To prepare a slurry by dispersing in water to a concentration of
At this time, it is preferable to add a small amount of a dispersant. This slurry is made into a long-mesh or round-mesh paper machine. The basis weight is preferably set in the range of 5 to 500 g / m ² depending on the application. The type of the yarn forming the papermaking sheet may be appropriately selected according to the purpose, as long as the single yarn diameter and the L / D satisfy the range of the present invention.
Alternatively, it is also preferable to use a mixture of two or three types of yarns having different shapes. The obtained sheet is entangled with a high-speed fluid flow. The fluid referred to here is a liquid or a gas, but water is most preferable in terms of ease of handling, cost, and magnitude of collision energy as the fluid. When using water, the water pressure varies depending on the type of yarn used and the basis weight of the papermaking sheet, but in order to obtain an average distance between fiber interlacing points of 150 μm, 5 to 200 kg / cm ² , preferably 10 to 200 μm.
Collide in the range of 80 kg / cm ² . In the case of the same yarn, the lower the fabric weight, the lower the water pressure, and the higher the fabric weight, the higher the water pressure. Further, in the case of a yarn having a high Young's modulus in the case of the same basis weight, it is possible to obtain a high strength, which is the object of the present invention, by treating with a higher pressure water stream. The diameter of the nozzle that jets the water flow is 0.01
~ 1 mm is preferred. The trajectory of the water flow may be a straight line parallel to the traveling direction of the papermaking sheet, or may be a curved shape obtained by a rotational motion of a header having a nozzle attached thereto or an oscillating motion reciprocating at right angles to the traveling direction of the sheet. May be. The entanglement of the multiple overlapping circular water flow trajectories obtained by the rotational movement is effective because the water jet area per sheet per nozzle per nozzle is large and efficient, and at the same time, the water flow trajectory lowers the commercial value depending on the application. This is advantageous because it has the advantage that the unevenness of the nonwoven fabric is hard to be seen and the strength ratio of the background of the nonwoven fabric is small. The method of processing the high-speed water flow on the papermaking sheet may be a method of alternately jetting the water flow on the front and back, or a method of processing only one side. The optimum number of processing times may be selected according to the purpose.

The water pressure conditions for the columnar water flow treatment of these papermaking sheets are selected so as to obtain a desired average fiber-to-fiber entanglement distance of 150 μm or less, and to obtain uniformity.
It is preferred to one or both surfaces treated with water pressure of 10~40kg / cm ² in the case of relatively small basis weight processing papermaking sheet of to 100 g / m ^2, in the case of relatively large weight per unit area of 150~500g / m ² Preferably, the columnar water jets are alternately sprayed on both sides at a water pressure of 30 to 80 kg / cm ² . The columnar water flow conditions for obtaining an entangled state having an average fiber entanglement distance of 300 μm or less will be further described. For example, a 100 g / m ² basis weight sheet made of 1 denier polyethylene terephthalate (PET) and 10 mm long short fibers On the other hand, nozzles with orifice diameters of 0.07 to 0.25 mm are perforated or arranged at nozzle intervals of 1 to 8 mm and 10 to 2
Using a nozzle header equipped with a large number of nozzles arranged in 0 rows, processing is performed once each for front and back alternately at a water pressure of 30 to 50 kg / cm ² . At this time, it is preferable that the nozzle header makes a circular rotation at 50 to 500 rpm (corresponding to a sheet processing speed of 2 to 20 m / min). Further, if necessary, if the water flow trajectory remaining on the sheet surface impairs product quality, insert a wire mesh of 40 to 100 mesh between the nozzle header and the sheet of the same structure to sprinkle the columnar water flow, and It is also a preferred embodiment to reduce the depth.

As an embodiment included in the production method for obtaining a high-strength wet nonwoven fabric of the present invention, after a sheet-making sheet is entangled with a columnar water stream, for example, the sheet is placed on a rough wire mesh (10 to 20 mesh),
It is also preferable to inject a columnar water flow from above the sheet to form a perforated pattern along the wire mesh pattern. The nonwoven fabric of the present invention obtained in this case has the effect of improving bulkiness, dimensional stability (elongation recovery rate), and the like, as compared to before the opening is patterned.

Furthermore, as a mode of post-processing of the high-strength wet nonwoven fabric obtained in the present invention, it is also a preferable method to perform cold or hot pressing with a sculpted roll (embossing roll) and to mold the surface. According to this method, since the entangled sheets are joined, the effect of improving the strength such as the tensile strength was recognized, and it was also found that an unexpected effect of improving the dimensional stability was also exhibited.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to examples.

In the examples, the measured values are measured by the following methods, and all percentages are% by weight.

1) Tensile strength: JISLI096 strip method 2) Tear strength: JISLI096 single tongue method 3) Delamination strength: Cut the nonwoven fabric to a width of 2.5 cm and a length of 13 cm. An adhesive tape (D3200, manufactured by Sony Chemical Co., Ltd.) is adhered to this sample, and then pressed at 70 ° C. and a pressure of 70 g / cm ² for 30 seconds to bond.

A cut is made between the adhesive tape and the nonwoven fabric of the measurement sample thus obtained, and both ends are gripped with an autograph chuck to perform measurement. The autograph measurement conditions are set as follows.

Tensile strength: 10 cm / min Chart speed: 10 cm / min In this case, the tape is strong, and the tape and the non-woven fabric are firmly adhered, so the tape is cut when the measurement sample tape is peeled off from the measurement sample. The peeling force acts so as to peel off one part of the nonwoven fabric from another part without peeling or peeling off the adhesive surface between the tape and the nonwoven fabric. Therefore, the delamination strength of the nonwoven fabric can be measured by this method.

An average value of a total of six values is obtained by selecting three values having a larger intensity value and three values having a smaller intensity value from a stress strain curve obtained when the measurement is performed by an autograph. The number of tests on the measurement sample shall be 5. Such measurement is similarly performed for each of the vertical direction (MD) and the horizontal direction (CD) of the nonwoven fabric, and the average value of the vertical / horizontal values is used as the delamination strength of the nonwoven fabric.

4) Flexibility: JISLI096 45 ° cantilever method The average value in the vertical direction (MD) and the horizontal direction (CD) is taken as the flexibility.

5) Average distance between fiber entanglement points: 100 with a scanning electron microscope
The measurement was performed at a magnification of 2 times, and the average value of 50 samples was taken.

Example 1 1d (10 μm) polyethylene terephthalate fiber was
It was cut into mm (L / D = 10 ³ ) and dispersed in water to obtain a 1% concentration slurry. The slurry was formed into a sheet with a tilting fourdrinier machine to obtain a sheet having a basis weight of 50 g / m ² . Fibers were entangled by jetting a columnar water stream having a water pressure of 30 kg / cm ² from a large number of 18 rows of nozzles having a nozzle diameter of 0.1 mm, a pitch between nozzles of 5 mm, and 18 rows. The distance between the nozzle and the papermaking sheet was 30 mm. Under the papermaking sheet, a stainless steel 80-mesh wire net was used as a support member, and suction dehydration was performed through the wire net. A similar treatment was applied to the opposite side of the sheet.

Subsequently, the water pressure was set to 18 kg / cm ² , and both sides were similarly subjected to jet treatment with a columnar water flow. Thereafter, it was dried to obtain an entangled sheet.
The average inter-fiber entanglement distance of this nonwoven fabric was 70 μm.
The columns showed the following values.

Tensile strength (vertical / horizontal): 2.0 / 1.9kg / cm Tear strength (vertical / horizontal): 1.6 / 1.4kg Delamination strength: 2100g / cm Flexibility (vertical / horizontal average): 28mm Obtained long fiber
Polyethylene terephthalate nonwoven fabric (Asahi Kasei Corporation)
"Asahi Kasei Spunbond" E3050 ”(weight per unit 50g /
m^Two) Were as follows.

Tensile strength: 2.4 / 1.0 kg / cm Tear strength: 1.1 / 1.2 kg Delamination strength: 230 g / cm Flexibility: 41 mm Thus, the nonwoven fabric of the present invention is a wet nonwoven fabric, but has a tensile strength and tear more than that of long fiber nonwoven fabric. It has high strength and much higher delamination strength. Furthermore, it has been found that it has an extremely soft feel and uniformity (basal uniformity) comparable to that of a conventional wet nonwoven fabric, and shows excellent quality as compared with any conventional nonwoven fabric.

Comparative Example 1 0.1 of polyethylene terephthalate (hereinafter abbreviated as PET)
d (3 μm) original yarn was made by a direct spinning method and cut into a length of 3 mm (L / D = 10 ³ ). This was subjected to papermaking and columnar flow treatment in the same manner as in Example 1. The average distance between the fiber entangled points of the obtained nonwoven fabric was 36 μm. The physical properties were as follows, and the tear strength was particularly low.

Tensile strength: 1.4 / 1.2kg / cm Tear strength: 0.2 / 0.2kg Delamination strength: 910g / cm Flexibility: 24mm Comparative Example 2 PET1 denier (10μm) as raw yarn, length 51mm (L / D
= 5.1 × 10 ³ ), and the paper was made at a basis weight of 50 g / m ² in the same manner as in Example 1. In the state of the slurry, the fibers were entangled with each other, and there were fiber lumps in some places, and the dispersibility was insufficient. This sheet was subjected to the same columnar flow treatment as in Example 1. However, pressure is first time is 40kg / cm ^{2, 2-th} time was 25kg / cm ^2. The average inter-fiber entanglement distance was 330 μm, and the physical properties were as follows.

Tensile strength: 0.8 / 0.7 kg / cm Tear strength: 3.6 / 3.4 kg Delamination strength: 210 g / cm Flexibility: 39 mm Comparative Example 3 5 denier (24 μm) of nylon 6 as raw yarn, 5 mm
(L / D = 0.21 × 10 ³ ) to obtain a paper sheet in the same manner as in Example 1. The dispersion state of the raw yarn in the slurry was good. The basis weight was 50 g / m ² . This sheet was subjected to entanglement treatment using a columnar flow under the same equipment and conditions as in Example 1.
The average inter-fiber entanglement distance was 340 μm. The physical properties were as follows.

Tensile strength: 0.4 / 0.2 kg / cm Tear strength: 0.8 / 0.6 kg Delamination strength: 195 g / cm Softness: 43 mm Comparative Example 4 3-denier (22 μm), long polypropylene fiber with a Young's modulus of 900 kg / cm ² as a raw yarn 20mm (L / D = 0.91 × 10 ³ )
Papermaking and columnar flow entanglement were performed in the same manner as in Example 1 using the short fibers of Example 1 to obtain an entangled nonwoven fabric having a basis weight of 50 g / m ² . The average fiber entanglement distance was 350 μm, and the physical properties were as follows.

Tensile strength: 0.1 / 0.09 kg / cm Tear strength: 0.7 / 0.3 kg Delamination strength: 180 g / cm Flexibility: 41 mm Example 2 1.5 d (13.1 μm) of nylon 66 as raw yarn, length 12.5
A 300 g / m ² papermaking sheet was prepared in the same manner as in Example 1 using an original yarn of mm (L / D = 0.95 × 10 ³ ). The column-shaped flow equipment has a nozzle diameter of 0.2 mm, a pitch between nozzles of 5 mm, the number of nozzle rows is 12, the distance between the nozzle and the papermaking sheet is 30 mm, and as a support member for the papermaking sheet
An 80 mesh wire mesh was used. While suction dehydration through a wire mesh, a columnar water flow was sprayed on both sides of the sheet at a first time at a water pressure of 70 kg / cm ^{2 and a} second time at a water pressure of 50 kg / cm ² . After drying, the result of measuring the average inter-fiber entanglement distance of the entangled nonwoven fabric
It was 90 μm. The physical properties are as follows. This nonwoven fabric was uniform and had good vertical / horizontal strength isotropy, and was suitable for civil engineering materials for roofing and the like.

Tensile strength: 16.1 / 15.7kg / cm Tear strength: 9.7 / 10.6kg Delamination strength: 1,900g / cm Flexibility: 74mm Example 3 1 denier of viscose cellulose fiber (rayon)
(9.7 μm), 15 mm (L / D = 1.55 × 10^ThreeUse the original yarn
In the same manner as in Example 1, 40 g / m^TwoGet a sheet of
Was. The conditions for the columnar flow entanglement treatment were as follows. Orifice
0.08mm diameter, 2mm nozzle pitch, 10 nozzle rows, nozzle
The distance between the paper sheet and the sheet is 50 mm, and the wire mesh of the support member is 60 mesh.
1st water pressure 15kg / cm^TwoThe second 23kg / cm^Two3rd time, 16kg / c
m^Two. Three times each for the front and back sides. Of the entangled non-woven fabric obtained after drying
The distance between the fiber entanglement points was 52 μm. Physical properties are as follows
Yes, cellulosic long fibers not measured simultaneously for comparison
Woven cloth ("Benrize" manufactured by Asahi Kasei Corporation) `` 40g / m^TwoToho
Has almost the same strength and softer texture
The non-woven fabric was excellent in wrapping properties.

Tensile strength: 0.14 / 0.10kg / cm Tear strength: 0.30 / 0.25kg Delamination strength: 1,020g / cm Flexibility: 26mm Tensile strength: 0.22 / 0.03 kg / cm Tear strength: 0.21 / 0.24 kg Delamination strength: 160 g / cm Flexibility: 34 mm Example 4 2.0 denier (14 μm), 20 mm (L / D = 1.42 × 1) of PET
0^Three) 20g / m^TwoWas obtained in the same manner as in Example 1.
Was. 30g / m of wood pulp in the same way^TwoPapermaking
I got it. PET sheet 20g / m^TwoPulp between two pieces
Three-layer laminated sheet sandwiching the papermaking sheet in a sandwich
And This laminated sheet is subjected to a columnar treatment under the following conditions.
Was. Nozzle diameter: 0.1mm, nozzle pitch: 5mm, number of nozzle rows: 1
5 rows, distance between nozzle and sheet: 30mm, water pressure: 1st 15kg / c
m^TwoThe second 28kg / cm^Two, Nozzle header rotation speed: 700rp
m, sheet speed: 6m / min, threading method: double-sided treatment both times. Profit
The average inter-fiber entanglement distance of the entangled sheet was 32 μm.
Was. The physical properties are as follows.
It is suitable for making use of disposable clothing such as surgical gowns.
Was.

Tensile strength: 4.1 / 4.0kg / cm Tear strength: 3.1 / 2.9kg Delamination strength: 1,300g / cm Flexibility: 42mm Example 5 1.5 denier (15.6μ) of polypropylene (PP) fiber
m), 17.5 mm (L / D = 1.1 × 10 ³ ), 70% yarn and 1 denier rayon fiber (9.7 μm), 12.5 mm (L / D = 1.3
× 10 ³ ) 30% of the original yarn was mixed, and 60 g
/ m ² was obtained. This sheet was subjected to a columnar flow treatment under the same conditions as in Example 4. The average inter-fiber entanglement distance of the entangled sheet was 150 μm, and the physical properties were as follows. This nonwoven fabric makes use of the antistatic and hygroscopic characteristics of cellulose and other materials,
It was suitable for a floppy desk liner.

Tensile strength: 3.6 / 3.3kg / cm Tear strength: 2.4 / 2.1kg Delamination strength: 1,230g / cm Flexibility: 39mm Example 6 Nylon 66 fiber 2 denier (15.1μm), 15mm (L /
D = 1.0 × 10 ³ ) was used to obtain a 95 g.m ² papermaking sheet. The papermaking sheet was entangled twice with the same columnar flow nozzle as in Example 1 on both front and back sides at a water pressure of 40 kg / cm ² . The average inter-fiber entanglement distance of this nonwoven fabric was 93 μm. Physical properties were as follows.

Tensile strength: 6.3 / 5.6kg / cm Tear strength: 3.5 / 2.7kg Delamination strength: 2.1kg / cm Flexibility: 37mm Polyurethane (concentration: 30%) dissolved in polyether formamide on the surface of this non-woven fabric Was applied so that the coating amount became 45 g / m ² . The resulting coating has a very soft feel because the non-woven fabric has no binder, and the surface of the formed polyurethane film has a fine and fine texture that is as natural and luxurious as the silver surface of natural leather. Met. Further, since the delamination strength is sufficiently high, it was confirmed that there was no damage such as delamination during use even when used as a material such as a chair upholstery.

Example 7 1.5 denier (13.1 μm) of nylon 6 fiber, 12.5 mm
(L / D = 0.95 × 10 ³ ) was used to obtain a 300 g / m ² papermaking sheet. Nozzle diameter: 0.2 mm, nozzle pitch: 5 mm, number of nozzle rows: 18 rows, spacing between paper sheet and nozzle: 30 mm, nozzle header rotation speed: 150 rpm, sheet speed: 5
The columnar flow treatment was performed at m / min. The average inter-fiber entanglement distance of this entangled sheet was 120 μm, and the physical properties were as follows.

Tensile strength: 18.9 / 16.4kg / cm Tear strength: 13.1 / 11.5kg Delamination strength: 2,210g / cm In this entangled sheet, polytetramethylene glycol is used as the polyol component, P, P'-diphenylmethane diisocyanate is used as the isocyanate component, and chain elongation. A 15% dimethylformamide solution of polyurethane using ethylene glycol as an agent was impregnated, squeezed to a squeezing ratio of 300%, and then coagulated in water. After drying, one side of the resulting impregnated sheet was
Buffing was performed with a belt sander equipped with 0-mesh emery paper. Next, the ground surface was heated and pressed with a calender roll having a surface temperature of 150 ° C. This buffing
The hot pressed surface was coated with 30% dimethylformamide having a composition of polybutylene adipate, P, P'-diphenylmethane diisocyanate and ethylene glycol with a gravure roll, coagulated in water, and then dried. In addition, polyethylene glycol, P,
A 40% solution of a mixed solvent of P 'diphenylmethane diisocyanate, methyl ethyl ketone of ethylenediamine and isopropyl alcohol was coated with a gravure roll, and the solvent was dried and removed at 130 ° C. The thus-obtained silver-like sheet-like material has an extremely good surface smoothness of the polyurethane coating layer, an excellent feeling of flexibility, and also has the following physical properties. It had sufficient strength to the extent that it could be obtained.

Tensile strength: 21.5 / 20.6 kg / cm Tear strength: 13.8 / 12.1 kg Flexibility: 81 mm Example 8 1 denier (10.7 μm) of nylon 66 fiber, 10 mm (L /
D = 0.93 × 10 ³ ) 0.1 denier, 5 mm PET obtained by direct spinning on a 200 g / m ² sheet made of short fibers
A 70 g / m ² papermaking sheet made of ultrafine short fibers was laminated. This was subjected to a columnar flow treatment under the same conditions as in Example 6 to obtain an entangled sheet. The average inter-fiber entanglement distance observed from the nylon 66 sheet surface of this nonwoven fabric was 93 μm, and the physical properties were as follows.

Tensile strength: 12.6 / 10.8 kg / cm Tear strength: 8.9 / 8.7 kg Delamination strength: 1,900 g / cm
Buffing was performed with a belt sander equipped with 40-mesh emery paper, and a cold water-insoluble, hot water-soluble 20% aqueous solution of polyvinyl alcohol was coated on the surface with a doctor knife and dried with hot air. This sheet was impregnated with a polyurethane emulsion in which a polyurethane composed of polypropylene glycol, isophorone diisocyanate and ethylenediamine was dispersed in water at a concentration of 1.5%, and water was removed by hot air drying to coagulate. Thereafter, the polyvinyl alcohol was removed with hot water of 80 ° C., and PET and nylon 66 were dyed in the same bath with a circular dyeing machine, washed and dried.
The sheet-like material thus obtained has an excellent suede effect on the surface of the PET 0.1 denier layer, shows a sufficient strength and soft feeling as a whole, and is a high-grade material suitable for clothing and interior fields. It was a feeling of artificial suede.

Tensile strength: 13.0 / 11.3kg / cm Tear strength: 6.7 / 6.0kg Flexibility: 63mm (Effect of the Invention) Since the high-strength wet nonwoven fabric of the present invention is configured as described above, it has the same strength as long-fiber nonwoven fabric. And has a very soft feel. The uniformity of the nonwoven fabric is comparable to that of a wet nonwoven fabric, and is far superior to a spunbond nonwoven fabric of a long-fiber nonwoven fabric.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view of the constituent fibers when observed from one surface in the planar direction of the nonwoven fabric of the present invention. f ₁ ~f ₇ ...... constituent fibers, a ₁ ~a ₇ ...... constituent fibers intertwined points of each other.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) D04H 1/00-18/00

Claims (9)

(57) [Claims] 1. A single yarn having a diameter of 7 to 17 μm and a fiber length of 20 mm
Below, the ratio L / D of the fiber length L to the diameter D of the single yarn is 0.8 × 10
^A high-strength wet nonwoven fabric in which ^{3 to} 2.0 × 10 ³ short fibers are three-dimensionally entangled with each other, the average inter-fiber entanglement distance is 150 μm or less, and the delamination strength is 1.0 kg / cm or more. 2. The high-strength wet nonwoven fabric according to claim 1, wherein the fiber length of the short fibers is 17.5 mm or less. 3. The high-strength wet nonwoven fabric according to claim 1, wherein the short fibers have a Young's modulus in a range of 50 to 700 kg / mm ² . 4. The high-strength wet nonwoven fabric according to claim 1, wherein the short fibers are made of any one or more of polyester fibers, polyamide fibers, polyolefin fibers, and regenerated cellulose fibers. 5. The high-strength wet-laid nonwoven fabric according to claim 1, wherein unevenness of the trajectory of the water flow on the surface is hardly visible. 6. The single yarn has a diameter of 7 to 17 μm and a fiber length of 20 mm.
Below, the ratio L / D of the fiber length L to the diameter D of the single yarn is 0.8 × 10
^A sheet of ^{3 to} 2.0 × 10 ³ short fibers is formed by a papermaking method, and then the high-speed fluid flow treatment is performed until the short fibers have an average inter-fiber entanglement distance of 150 μm or less and a delamination strength of 1.0 kg / cm or more. A method for producing a high-strength wet nonwoven fabric, wherein the nonwoven fabrics are three-dimensionally entangled with each other. 7. The method for producing a high-strength wet nonwoven fabric according to claim 6, wherein the water pressure in the fluid treatment is 5 to 200 kg / cm ² . 8. The method for producing a high-strength wet nonwoven fabric according to claim 6, wherein the diameter of the fluid treatment nozzle is 0.01 to 0.25 mm. 9. The method for producing a high-strength wet nonwoven fabric according to claim 6, wherein the nozzle header for fluid treatment is rotating or reciprocating.