JPH11107149A - Nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonwoven fabric having a specific weight per unit area, uniformity, high strength, soft touch feeling and useful for medical drapes, surgical gown, under pad, diaper, napkin, mask or the like by entangling polytrimethylene terephthalate fibers by columnar stream. SOLUTION: This nonwoven fabric having 30-200 g/m<2> weight per unit area is obtained by entangling polytrimethylene terephthalate fibers having >=50%, >=70 mol.%, further preferably 180 mol.%, especially preferably >=90 mol.% trimethylene terephthalate unit by columnar stream.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven fabric having a high strength and a soft feel.

[0002]

2. Description of the Related Art In recent years, non-woven fabrics have been used in alternative applications such as conventional woven or knitted fabrics or functional applications which cannot be handled by woven or knitted fabrics, taking advantage of their excellent performance and high productivity. ing. Various types of non-woven fabrics are known. Typical examples are long-fiber dry non-woven fabrics by spunbonding or flash spinning, short-fiber dry non-woven fabrics having a relatively long fiber length obtained by melt-blowing, and short fibers. After carding, it is made into a sheet with a cross layer, air layer, etc., and entangled with a needle punch according to the purpose, or an adhesive, a short fiber dry non-woven fabric obtained by bonding with heat fusion fibers, etc., carding or paper making method A wet nonwoven fabric or the like obtained by forming a sheet and then entangled with a columnar water flow is known.

[0003] In a long-fiber dry nonwoven fabric obtained by a spunbonding method, a flash spinning method or the like, since the fibers constituting the nonwoven fabric are filaments, the nonwoven fabric obtained by thermocompression bonding these fibers has a tensile strength, a tear strength and the like. It has a great feature and is widely used for industrial materials that require high strength. However, these nonwoven fabrics are formed by index lamination using an air flow, a gas flow, or the like in the sheet forming method, so that the uniformity of the sheet, that is, the unevenness of the basis weight is large, and since the filament bonding means is generally thermocompression bonded, the elongation is increased. There was a drawback that it was hard and lacked drapability. In addition, the short-fiber dry nonwoven fabric obtained by bonding sheets formed by the card method with needle punches, adhesives, and heat-fusible fibers is inferior in strength because the fiber length is shorter than that of the long-fiber dry nonwoven fabric. In many cases, bonding is performed with an adhesive or the like in order to compensate for the problem, and in this case, there is a disadvantage that the texture is inevitably hardened.

[0004] The so-called spunlace type non-woven fabric of no binder obtained by entanglement of a sheet formed by the card method with a columnar water stream is softer than a card-type dry non-woven fabric joined by a spun bond, an adhesive or a heat fusion fiber. It is excellent in terms of texture, but has disadvantages such as insufficient uniformity of the sheet and insufficient delamination strength.

On the other hand, a nonwoven fabric formed by a papermaking method in which extremely short fibers are dispersed in water to form a sheet has a characteristic that the uniformity is incomparably better than a dry nonwoven fabric. However, in order to disperse the fibers uniformly in water, the fiber length is generally required to be extremely short, about 3 to 7 mm. Therefore, the nonwoven fabric obtained by this method has extremely low strength and is required to have very low strength in use. Are not limited to those areas. Further, in the papermaking method, since it is usually pressure-bonded with a felt or a Yankee dryer, there is a disadvantage that the thickness is small and the density is high, resulting in a paper-like texture. As described above, conventional nonwoven fabrics have disadvantages in accordance with the characteristics of their manufacturing methods, and have not yet been provided with nonwoven fabrics having excellent uniformity, high strength, and soft texture. Was.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a sheet formed from short fibers by a card method or a papermaking method, or a sheet formed by synthetic filament fibers or regenerated filament fibers and a card method or a papermaking method. A sheet formed from short fibers according to the above is laminated and subjected to a columnar flow treatment, so that the short fibers are entangled with each other, or the long fiber filaments and the short fibers are mutually entangled. The purpose of the present invention is to provide a nonwoven fabric improved in that it is paper-like.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned problems, and as a result, the use of fibers made of polytrimethylene terephthalate polymer as long fiber filaments or short fibers for use in the nonwoven fabric has led to these problems. Have been solved, and the present invention has been achieved. That is, the present invention is a nonwoven fabric having a basis weight of 30 to 200 g / m ² entangled by a columnar flow, wherein the fibers constituting the nonwoven fabric are polytrimethylene terephthalate fibers.

In the present invention, the term "polytrimethylene terephthalate fiber" refers to a polyester fiber having a trimethylene terephthalate unit as a main repeating unit, and the trimethylene terephthalate unit is about 50% or more, preferably 70 mol% or more, more preferably 80 mol% or more, particularly preferably 90 mol% or more. Therefore, the total amount of the other acid component and / or glycol component as the third component is about 50 mol% or less, preferably 30 mol%.
The polytrimethylene terephthalate is contained in an amount of preferably 20 mol% or less, particularly preferably 10 mol% or less.

[0009] Polytrimethylene terephthalate is produced by condensing terephthalic acid or a functional derivative thereof with trimethylene glycol or a functional derivative thereof under suitable reaction conditions in the presence of a catalyst. In this production process, an appropriate one or more third components may be added to form a copolymerized polyester, or a polyester other than polytrimethylene terephthalate such as polyethylene terephthalate, a polyester such as nylon, and polytrimethylene terephthalate may be separately prepared. , And then blended or composite-spun (sheath core, side-by-side, etc.).

The third components to be added include fatty acid dicarboxylic acid (oxalic acid, adipic acid), alicyclic dicarboxylic acid (cyclohexanedicarboxylic acid, etc.), aromatic dicarboxylic acid (isophthalic acid, sodium sulfoisophthalic acid), fatty acid Aliphatic glycols (ethylene glycol, 1,2-propylene glycol, tetramethylene glycol, etc.), alicyclic glycols (cyclohexane glycol, etc.), aromatic dioxy compounds (hydroquinone bisphenol A, etc.),
Examples thereof include aliphatic glycols containing aromatics (such as 1,4-bis (β-hydroxyethoxy) benzene) and aliphatic oxycarboxylic acids (such as P-oxybenzoic acid). Also,
Compounds having one or more ester-forming functional groups (such as benzoic acid or glycerin) can also be used in a range where the polymer is substantially linear.

Further, polytrimethylene terephthalate has a matting agent such as titanium dioxide, a stabilizer such as phosphoric acid,
UV absorbers such as hydroxybenzophenone derivatives, crystallization nucleating agents such as talc, lubricating agents such as Aerosil, antioxidants of hindered phenol derivatives, flame retardants, antistatic agents, pigments, fluorescent brighteners, infrared absorbers, An antifoaming agent may be contained. The nonwoven fabric of the present invention may be composed of long fibers or short fibers, but is preferably composed of long fibers from the viewpoint of strength.

The sheet comprising the polytrimethylene terephthalate fiber of the present invention is produced, for example, by the following method. The sheet of short fibers forms short fibers having a predetermined fiber length by cutting a large number of continuous filament bundles formed by melt-spinning the polytrimethylene terephthalate polymer from a large number of spinning nozzles. This is dispersed in water to a concentration of 0.1 to 3% to prepare a slurry. At this time, it is preferable to add a small amount of a dispersant. The slurry is made into a paper sheet by using an optional paper machine.

Further, the sheet may be formed by a carding method in which short fibers are opened and combed with a needle cloth mounted on a drum of a card machine to arrange the short fibers in a predetermined direction to form a sheet. In the case of a sheet made of long fibers, a large number of continuous filaments obtained by melt-spinning a polytrimethylene terephthalate polymer from a large number of spinning nozzles were subjected to traction by an air jet or the like. Thereafter, a method of forming a sheet on a moving collecting device may be employed. In the present invention, the basis weight is 30 to 200 g / m ² , preferably 50 to 200 g.
/ M ² , and if it is less than this, the strength is insufficient, and if it exceeds this, confounding becomes insufficient and the object of the present invention is not achieved.

After the obtained sheets are laminated singly or in any combination, they are entangled by a pouring flow. The pouring flow referred to here is a high-speed fluid composed of liquid or gas, but water is most preferable in terms of ease of handling, cost, and the magnitude of collision energy as a liquid. When water is used, the water pressure varies depending on the basis weight of the papermaking sheet to be used, but is 5 to 200 kg / cm ² , preferably 10 to 200 kg / cm ² .
Collision is made in the range of ８０80 kg / cm ² . In the case of a low weight, the water pressure is low, and the higher the weight, the higher the water pressure may be set. In the case of the same basis weight, in the case of a yarn having a high Young's modulus, the treatment with a higher water pressure can obtain the high strength intended for the present invention.

The trajectory shape of the water flow may be a straight line parallel to the traveling direction of the sheet, or may be a curved shape obtained by a rotary motion of a header to which a nozzle is attached or a sliding motion reciprocating at right angles to the traveling direction. There may be. The entanglement of multiple overlapping circular water flow trajectories obtained by the rotational movement is effective because the water jet area per sheet per nozzle increases and the water flow trajectory lowers the commercial value depending on the application. This is preferable because the trace of the non-woven fabric is difficult to see. Further, the strength ratio of the background of the nonwoven fabric is small, which is preferable.

The method of processing the high-speed water flow on the sheet is as follows.
A method of injecting a water flow alternately between the back and the front may be used, or only one side may be treated. Also, the optimum number of processing times may be selected according to the purpose. In particular, the fibers constituting the non-woven fabric are long fibers, and the long fiber groups are arranged in a sinusoidal curve as a whole to form a web, and the long fiber groups are substantially the same on the upper surface of the web. Another web with a sinusoidal curve and a plurality of layers superimposed on it in different phases is entangled with a group of long fibers. And is particularly preferable because of excellent dimensional stability.

In the nonwoven fabric having such a structure, since the long fiber group is arranged by drawing a sinusoidal curve,
Entanglement between the long fibers becomes stronger, and the strength in the width direction of the nonwoven fabric is increased. Further, in combination with the fact that the fibers constituting the nonwoven fabric are polytrimethylene terephthalate fibers, the strength and flexibility are further improved. As for the long fiber group referred to here, the continuous long fiber has 1,000 to 10,000 fibers / inch, preferably 30
It is preferable that the long fibers are arranged in a range of 100 to 6000 fibers / inch, and the long fibers are arranged in a sinusoidal curve to constitute a web. Further, the long fibers are arranged on the upper surface of the web. However, different webs arranged to draw almost the same sinusoidal curve are superimposed in multiple layers, different phases, the long fiber groups are entangled, the intersections are adhered, and as a whole This constitutes the resulting woven structure.

The structure of the woven structure referred to here is shown as a two-phase alternating current, a three-phase alternating current, a multi-phase alternating current, or the like.
The shape of the sine wave curve at this time is such that a web is formed by drawing various shapes of sine wave curves by combining in the range of amplitude 2 to 300 mm, preferably 10 to 200 mm, wavelength 5 to 2000 mm, and preferably 100 to 1500 mm. be able to. The specific manufacturing method is, for example, as follows. The melt spun fiber is given a sinusoidal wave on the net conveyor by giving the swinging motion in the traveling direction of the conveyor and the right and left direction perpendicular to it using a swinging device on the net conveyor which advances the long fiber at a low speed. Draw a curve to form the web.

Subsequently, the web formed on the net conveyor is supported on a net or a roller, and 10 to 100 kg / cm ² , more preferably 3 to 100 kg / cm ² , from the web side.
High-pressure water of 0 to 80 kg / cm ² is sprayed from a nozzle to entangle the long fiber groups, whereby the long fibers are entangled.

The polytrimethylene terephthalate fiber constituting the nonwoven fabric of the present invention has an elastic modulus of 25 to 40 g.
/ D, and the elastic recovery after elongation at 20 ° C. for 3 minutes is preferably 85 to 100%. 25g elastic modulus
When it is less than / d, the texture becomes very soft, but the hardness and the stiffness are insufficient, and the workability at the time of product processing may be deteriorated. Conversely, if it exceeds 40 g / d, the stiffness of the fibers becomes large, resulting in a soft texture, and insufficient entanglement between the fibers may result in insufficient strength. Further, when the elastic recovery rate is less than 85%, the recovery rate of the fiber stretched by the water flow during the columnar flow treatment becomes insufficient, and sufficient strength may not be obtained.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The measured values in the examples are measured by the following methods. (1) Tensile strength: Measured according to JIS-1096, strip method. (2) Flexibility: Measured according to JIS-1096, 45 ° cantilever method, and the average value in the vertical direction (MD) and the horizontal direction (CD) is defined as the flexibility.

(Example 1) A polytrimethylene terephthalate fiber of a single yarn 1d having an elastic modulus of 30 g / d and an elastic recovery rate of 95% was cut into 10 mm, dispersed in water and 1%
A slurry of a concentration was obtained. The slurry was sheet-formed with a 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 nozzle pitch of 5 mm, and 18 rows. The distance between the nozzle and the sheet was 30 mm, and a 100-mesh metal mesh support made of stainless steel was formed below the sheet. A similar treatment was performed on the opposite side of the sheet. Then, the water pressure was set to 18 kg / cm ² , and both surfaces were similarly subjected to jet treatment with a columnar water flow. Thereafter, it was dried to obtain an entangled sheet.

The physical properties of this sheet were as follows. Tensile strength: 2.0 (vertical) /1.0 (horizontal) kg / cm Flexibility (vertical, horizontal average): 20 mm As a comparison, a polyethylene terephthalate long-fiber nonwoven fabric obtained by a spun bond method (“Asahi Kasei Kogyo Co., Ltd.” E
3050 ") (weight per unit area: 50 g / m ² ) were as follows. Tensile strength: 2.4 (vertical) /1.0 (horizontal) kg / cm Flexibility: 42 mm

(Example 2) Polytrimethylene terephthalate is melt-spun on a net conveyor described below. That is, as a spinneret, a spinning hole of 0.8 mm has a length of 1.5 m.
90 rows in the traveling direction on a net conveyor made of vinylidene chloride of 24 mesh with m pitches, and 10 rows in a direction perpendicular thereto.
The arrangement of 00 rows was used. The spinning solution was discharged at a rate of 0.1 g / min per spinning hole.

The traveling speed of the net conveyor is 10 m.
/ Min, and a swinging device in a lateral direction perpendicular to the traveling direction of the conveyor was given to the net conveyor at a rate of 200 times / min using a swinging device. Subsequently, a water pressure of 30 kg was applied to the web formed on the net conveyor from a number of nozzles having a nozzle diameter of 0.1 mm, a pitch between nozzles of 5 mm, and 18 rows.
The fibers were entangled by injecting a columnar water flow of / cm ² .

The distance between the nozzle and the sheet is 30 mm.
Below the papermaking sheet was a 100-mesh metal mesh support made of stainless steel, which was suction-dehydrated through the wire mesh. A similar treatment was performed on the opposite side of the sheet. Then, the water pressure was 18 kg /
cm ² , and both sides were similarly sprayed with a columnar water flow. Thereafter, it was dried to obtain an entangled sheet. The physical properties of this sheet were as follows. Tensile strength: 2.2 (vertical) /1.0 (horizontal) kg /
cm Softness (vertical, horizontal average): 22 mm As a comparison, a polyethylene terephthalate long-fiber nonwoven fabric obtained by a spunbond method (“E” manufactured by Asahi Kasei Corporation)
3050 ") (weight per unit area: 50 g) were as follows. Tensile strength: 2.4 (vertical) /1.0 (horizontal) kg / cm Flexibility: 42 mm

(Comparative Example 1) A 1d polyethylene terephthalate fiber having an elastic modulus of 75 g / d and an elastic recovery rate of 40% was cut into 10 mm. This was subjected to papermaking and columnar flow treatment in the same manner as in Example 1. Physical properties were as follows. Tensile strength: 1.5 (vertical) /1.0 (horizontal) kg / cm Flexibility: 32 mm As described above, the nonwoven fabric of the present invention has the same tensile strength as a long-fiber nonwoven fabric while being a nonwoven fabric by columnar flow, and It has a very soft texture. Also, compared to non-woven fabric by the same column flow using polyethylene terephthalate fiber,
It was found to have excellent tensile strength and flexibility.

[0028]

As described above, the nonwoven fabric of the present invention has the uniformity which is a characteristic feature of the nonwoven fabric by the columnar flow method, has high strength and soft texture overcoming its disadvantages, and can be expected from conventional nonwoven fabrics. It has a function that was not available, and can be used for applications that were difficult to apply with conventional nonwoven fabrics. Preferable examples thereof include materials for medical care and sanitary materials, for example, medical materials such as medical drapes, surgical gowns, and underpads, and sanitary materials such as diapers, napkins, and masks. In these applications, the characteristics of the nonwoven fabric of the present invention having a rich drape property and high strength are well utilized.

Claims (1)

[Claims] 1. A basis weight entangled by a columnar flow is 3
A nonwoven fabric of 0 to 200 g / m ² , wherein the fibers constituting the nonwoven fabric are polytrimethylene terephthalate fibers.