JPH08158233A - Reinforced nonwoven fabric and its production - Google Patents

Abstract

PURPOSE: To obtain readily producible reinforced nonwoven fabric useful for a filter, etc., having flexibility, lint-free properties, drape properties, soft handle and excellent balance of warp and weft strength, by reinforcing a short fiber web layer with a strengthening substrate layer, an air-permeable orientated material. CONSTITUTION: Fibers of web layers 11 and 11' obtained from cellulosic fibers or synthetic fibers in a short fiber state are interlaced with a strengthening substrate layer 12, an air-permeable orientated material by a spun lace method by a high-pressure water flow injector 15 and integrated. Reinforced nonwoven fabric 19 having excellent mechanical strength such as peel strength, reinforcing function and relative lightness in weight is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforced nonwoven fabric having improved mechanical strength, drapeability, flexibility, texture and the like and a method for producing the same. More specifically, industrial materials such as filters and industrial wipers, surgical gowns,
The present invention relates to a reinforced nonwoven fabric widely used for medical disposable products such as sheets, towels and masks, and a method for producing the same.

[0002]

2. Description of the Related Art A method of intertwining fibers constituting a web by injecting a high-pressure fluid onto a short fiber web to give an appropriate entangled structure and specific physical properties to the web is widely known as a spunlace method. It has been implemented. Nonwoven fabric manufactured by the spunlace method has more flexibility, lint-free property and drape property because each fiber has more freedom to move than other non-woven fabrics because there are no bonding points between fibers. It has a soft texture. However, since the fibers are not bonded to each other, they are weak in strength, unstable and easily deformed. In addition, since the injection traces of high-pressure fluid remain continuously in the vertical direction (flow direction) of the web, the strength balance between the vertical and horizontal directions is poor, and the entanglement process becomes complicated if an attempt is made to improve the strength balance. There are drawbacks. As a method of improving such a defect, a method of using a non-woven fabric made of staple fibers as a reinforcing base material (JP-A-54-82481),
A method using a reinforcing material composed of a woven fabric, a knitted fabric or a non-woven fabric (JP-A-54-101981, JP-A-61-22).
5361), a method of using wood pulp as a reinforcing base material (JP-A-59-94659), and the like.

[0003]

However, all of the methods of improvement by the reinforced support found in the disclosed techniques achieve the object of reinforcement to some extent, but are further characterized by the flexibility of the nonwoven fabric by the spunlace method. A non-woven fabric that retains lint-free property, drape property, soft texture, etc., and has a good strength balance in the vertical and horizontal directions and is simple and economical, or a manufacturing method thereof is still satisfactory. Absent.

[0004]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a multi-layer laminate in which a specific base material is superposed on a web layer made of short fibers as a reinforcing support layer. By injecting a high-pressure water stream onto the body, the short fibers are entangled with the reinforced support layer to improve the strength balance in the longitudinal and transverse directions, and also the flexibility, lint-free property, drape property, soft texture, etc. The present invention has been completed by finding that a reinforced nonwoven fabric having the above can be obtained. That is, a first invention of the present application is that the web layer and the reinforced support layer are formed by intertwining the fibers of the web layer made of short fiber-like cellulosic fibers or synthetic fibers with the reinforced support layer by a spunlace method. A reinforced non-woven fabric obtained by integrating the reinforced non-woven fabric, wherein the reinforced support layer comprises a breathable oriented body. In addition, a second invention of the present application is to superimpose a web layer made of short fibrous cellulosic fibers or synthetic fibers on one side or both sides of a reinforced support layer made of at least one layer of breathable alignment material and superposing the web layers. 30-300kg while conveying the laminated body formed by
High-speed water stream of / cm ² is injected, processing speed is 1 to 150 m / min
The method for producing a reinforced non-woven fabric is characterized in that the web layer and the reinforced support layer are integrated with each other by performing the entanglement process.

The present invention will be described in more detail below. The web layer composed of short-fiber cellulose fibers or synthetic fibers used in the present invention is rayon, regenerated cellulose fibers such as cupra, semi-synthetic cellulose fibers such as acetate, cotton, linters, natural cellulose fibers such as pulp, polyethylene, One of synthetic fibers such as polypropylene, polyester, polyamide, polyacrylonitrile, and vinylon or conjugate fiber, or a mixture thereof is used as a raw material. To form a web layer, wet-spun recycled fibers or melt-spun synthetic fibers are cut, and the fibers are aligned by a card machine to form a web, or melt-blown. A method of spinning to form a web, a method of aligning natural fibers with a card machine to form a web, or a method of beating to make paper are used.

The single yarn fineness of the short fibers is preferably 0.0
5-20 denier (d), more preferably 0.1-6 d
And the fiber length is preferably 5 to 60 mm, more preferably 10 to 50 mm. Single yarn fineness is 0.05d
If it is less than 20 d, the lint-free property is poor, and if it exceeds 20 d, the texture is poor. If the fiber length is less than 5 mm, the entanglement is insufficient and the peel strength is low, and if it exceeds 60 mm, the dispersibility is deteriorated, which is not preferable. The basis weight of the web layer is preferably 20 to 250 g / m ² , more preferably 50 to 100 g / m ^2.
Is. If the basis weight is less than 20 g / m ² , the density of the fibers will be uneven during the high-pressure water treatment, and if it exceeds 250 g / m ² , the density will be too high and the moldability will be poor, so both are not preferable.

The present invention uses a breathable alignment material as the reinforcing support layer. As the breathable oriented body, a uniaxially or biaxially oriented perforated film, punching film or the like made of a thermoplastic resin as a raw material can be used, and preferably (a) a vertically uniaxially oriented reticulated film. ,
A non-woven fabric or a woven fabric is used in which at least one kind of uniaxially oriented body selected from (b) a laterally uniaxially oriented reticulated film and (c) a uniaxially oriented multilayer tape is laminated or woven in a weft manner so that the orientation axes intersect.

The longitudinally uniaxially oriented reticulated film (a) made of the above-mentioned thermoplastic resin has a second melting point lower than that of the first thermoplastic resin on one or both sides of the first thermoplastic resin layer.
The multilayer film laminated with the thermoplastic resin layer of is uniaxially stretched or uniaxially rolled in the longitudinal direction (film molding direction),
Moreover, it is desirable that the fibers are split in the machine direction using, for example, a slitter before and / or after the stretching or rolling. FIG.
FIG. 4A is a partially enlarged perspective view of an example of (a) a vertically uniaxially oriented reticulated film. In the figure, the longitudinally uniaxially oriented reticulated film 1 is obtained by laminating the second thermoplastic resin layer 3 on both surfaces of the first thermoplastic resin layer 2 and performing stretching or rolling and longitudinal fiber splitting treatment. is there. In the figure, 4 is a trunk fiber and 5 is a branch fiber.

The laterally uniaxially oriented reticulated film (b) made of a thermoplastic resin is a second thermoplastic resin having a melting point lower than that of the first thermoplastic resin on one or both surfaces of the first thermoplastic resin layer. A multilayer film laminated with a plastic resin layer is uniaxially stretched or uniaxially stretched in the transverse direction (direction perpendicular to the film forming direction), and slits in the transverse direction before and / or after stretching or rolling, for example, with a hot blade. Is formed. FIG. 2 is a partially enlarged perspective view of an example of the (b) laterally uniaxially oriented reticulated film. In the figure, the laterally uniaxially oriented reticulated film 6 is also composed of a multilayer structure in which the second thermoplastic resin layer 3 is laminated on both surfaces of the first thermoplastic resin layer 2.

Further, using a thermoplastic resin as a raw material (c)
The uniaxially oriented multilayer tape is obtained by cutting a multilayer film in which a second thermoplastic resin layer having a melting point lower than that of the first thermoplastic resin is laminated on one or both surfaces of the first thermoplastic resin layer, and before and / or Alternatively, it is uniaxially oriented by stretching or rolling later. FIG. 3 is a partially enlarged perspective view of an example of (c) uniaxially oriented multilayer tape. The uniaxially oriented multilayer tape 7 is also obtained by laminating the second thermoplastic resin layer 3 on both surfaces of the first thermoplastic resin layer 2, stretching and cutting the same.

The first thermoplastic resin is a homopolymer of α-olefin such as high density and medium density polyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1, polyhexene-1, propylene-. Examples thereof include polyolefins such as α-olefin mutual copolymers such as ethylene copolymers, polyamides, polyesters, polycarbonates, polyvinyl alcohols and the like.

The second thermoplastic resin having a melting point lower than that of the first thermoplastic resin includes high density, medium density and low density polyethylene, linear low density polyethylene, ultra low density polyethylene, ethylene-vinyl acetate copolymer. Copolymer; ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer; ethylene-acrylic acid ester copolymer such as ethylene-ethyl acrylate copolymer and ethylene-methacryl such as ethylene-ethyl methacrylate copolymer Examples thereof include acid ester copolymers; ethylene- (maleic acid or its ester) copolymers; propylene-based polymers such as polypropylene and propylene-ethylene copolymers; and polyolefins modified with unsaturated carboxylic acids. For manufacturing reasons and for preventing the decrease in strength increased by stretching or rolling of the uniaxially oriented body, the difference in melting point between the second thermoplastic resin and the first thermoplastic resin is preferably 5 ° C. or more, and preferably Is 10 ° C. or higher.

Next, specific examples of the breathable alignment material used in the present invention are shown in the drawings. FIG. 4 is a partial plan view of a nonwoven fabric 8 in which (a) two longitudinal uniaxially oriented reticulated films 1 are laminated. Figure 5
FIG. 6 is a partial plan view of a nonwoven fabric 9 in which (c) two sets of uniaxially oriented multilayer tapes 7 are laminated, and FIG. 6 is a partial perspective view of a woven fabric 10 in which (c) the uniaxially oriented multilayer tape 7 is woven. The breathable uniaxially oriented body preferably has a basis weight of 5 to 50 g / m ² . As a specific example of the nonwoven fabric 8 which is an example of the breathable uniaxially oriented body, "Nisseki Wallif" (trade name, manufactured by Nisseki Plast Co., Ltd.) can be mentioned.

In the present invention, the combination of the web layer composed of the short fiber type cellulosic fiber or the synthetic fiber and the reinforcing support layer is a short fiber web layer (A) and the reinforcing support layer (B).
It is possible to use a structure having two or more layers in which the layers are alternately stacked. For example, A / B, A / B / A, B / A / B, A / B / A /
Any combination of B, B / A / B / A / B, etc. is possible.

Next, the method for producing the reinforced nonwoven fabric of the present invention will be described in detail. The manufacturing method includes (1) a web layer forming step, (2) a supplying step of supplying the web layer and the reinforcing support layer, and (3) a high-pressure hydroentanglement step of performing a water injection process,
It is composed of (4) drying step, and (5) product winding step.

First, in the web layer forming step (1), various forms are used as a method for arranging and forming webs depending on the kind of raw material and the final use. As the characteristics of the web, it is required that the fibers are evenly distributed in the plane of the web.As the web fiber arrangement method, a card parallel method by a mechanical card web forming method in which two-dimensionally arranged in the longitudinal direction, and a diagonal method are used. Card cross-layer method by mechanical cross-web forming method that cross-arranges in the direction, semi-random method by semi-random machine with two-dimensional and three-dimensional intermediate arrangement, fibers are blown on air blow and accumulated on mesh screen A random method in which three-dimensional at random arrangement is performed by an air-ray type web forming method of forming a web by forming a web is exemplified. In addition, the method of forming the web differs depending on the type of raw material.When cutting the raw material such as wet-spun recycled fiber or melt-spun synthetic fiber by the usual method, the fiber is drawn with a card machine. A method of forming a uniform web is used, and a method of forming a web as it is in the case of spinning by a melt blow method is used. Further, there are a method of forming a web by aligning natural fibers with a card machine, a method of forming a web by beating, and a wet web forming method.

FIG. 7 is a schematic view showing an example of the step (2) and subsequent steps of the above steps. In the supply step, the reinforcing support layer 1 fed from the supply roll 12a
The web layer 11 fed from the supply roll 11a is supplied to the upper surface of No. 2 or the web layers 11 and 11 ′ from the supply rolls 11a and 11a ′ are supplied to both surfaces of the reinforcing support layer 12. Alternatively, the web layer directly supplied from the web layer forming step is overlaid with the reinforcing support layer fed from the supply roll, and the web layer is fed to the subsequent high-pressure water entanglement step.

In the next (3) high-pressure hydroentangling step, a fed web layer and a reinforced support layer are laminated on a screen or roll as the treated water-permeable or impermeable transfer support 13. A plurality of thin water streams 15a are jetted from the high-pressure water stream injector 15 to the body 14. When jetting a high-pressure water stream, the energy of the high-pressure water stream causes the stacked web layers and the reinforced support layer to be displaced from each other, or when the two layers are separated from each other. Since a uniform reinforced non-woven fabric having physical properties cannot be obtained, it is preferable to immerse the laminate in water 16a in the water immersion device 16 before jetting the water stream. Further, after the water jet, in order to improve the drying efficiency, it is preferable to suck and remove the moisture by the moisture suction device 17 provided with a reduced pressure suction means or the like.

In the above high-pressure water flow entanglement process, when the high-pressure water flow treatment is performed on the screen, the screen is not particularly limited, but in order to facilitate the discharge treatment of the treated water, the material and the material are selected according to the purpose and application. It is preferable to select the opening and the wire diameter. The screen opening is usually 20-20
It is 0 mesh. In the method using the treated water-permeable transfer support, the treated water is easily discharged, so that it is possible to avoid scattering the web by spraying the water stream and impairing the uniformity. However, a considerable amount of energy still remains in the treated water that has once passed through the web, and the energy utilization efficiency is not high. On the other hand, in the method of using the treated water-impermeable transfer support, the jet water flow that has permeated the web collides with the transfer support and becomes a repulsive flow, which acts on the web again. Entanglement is efficiently performed by the interaction. However, since the high-pressure water stream is jetted to the web floating in the water, there is a drawback that the entanglement stability becomes low. Among these, the method of performing the injection treatment of the high-pressure water stream on the treated water-permeable transfer support is preferable in that stable treatment can be performed and a uniform reinforced nonwoven fabric can be obtained.

The pressure of the jet of water is 30 to 300 kg / cm ² , preferably 60 to 150 kg / cm ² . Pressure is 30
If it is less than kg / cm ² , the entanglement effect is insufficient, and 300 kg
If it exceeds / cm ² , the cost of the high-pressure water stream increases, and it is difficult to handle. 1 injection
It is performed more than once, but it is preferable to perform entanglement by three times of injection. That is, injection of high pressure and large amount of water mainly for entanglement, injection of low pressure and small amount of water for surface finishing,
In addition, it is possible to selectively use the intermediate injection and the like. The shape of the high-pressure fluid is not particularly limited, but a columnar flow is preferable from the viewpoint of energy efficiency. The cross-sectional shape of the columnar flow is determined by the cross-sectional shape of the nozzle or the internal structure of the nozzle outlet, and can be freely selected according to the material of the web, the purpose, the application, and the like. The treatment speed of high-pressure water jet is 1 to 150 m / min, preferably 20 to 1
It is 00 m / min. If the processing speed is less than 1 m / min, the productivity is low, and if the processing speed is more than 150 m / min, the entanglement effect is insufficient.

The laminate composed of the web layer and the reinforcing support layer, which have been entangled by the injection of the high-pressure water stream, is then fed to (4) the drying step, and in the drying step, for example, the oven 18, the hot air oven or the hot cylinder is used. And so on.
Before drying, it may be dehydrated by suction in advance,
Further, the web may be shrunk in the drying step. The non-woven fabric dried in this way is wound up as a reinforced non-woven fabric 19 in the product winding step (5) to become a product.

[0022]

Since the reinforced nonwoven fabric of the present invention is reinforced by the breathable oriented body, it has high strength in spite of being relatively lightweight, which can be achieved by the conventional reinforced nonwoven fabric. It is an excellent advantage that it did not have. Further, the reinforced nonwoven fabric of the present invention is generally excellent in the strength balance in the vertical and horizontal directions, and therefore, as seen in many conventional reinforced nonwoven fabrics, it exhibits excessive strength in the longitudinal direction against insufficient strength in the transverse direction. Rather, it is possible to provide a product with balanced vertical and horizontal strength.

[0023]

The present invention will be described below with reference to examples. <Example 1, Comparative Example 1> The fiber fineness and length are 2dx
A web layer composed of short rayon fibers (A ₁ ) having a basis weight of 45 mm and a basis weight of 30 g / m ² and a basis weight of 16 g / m ² as a breathable alignment material
Non-woven fabric using polyethylene uniaxially oriented body (trade name:
Nisseki Wallif SSS-T, Nisseki Plast Co., Ltd.) (B ₁ )
A reinforced support layer consisting of A ₁ / B ₁ / A ₁ is overlaid and placed on an endless belt conveyor consisting of a treated water permeable screen equipped with a 100 mesh wire mesh. 60kg in the first row through three rows of nozzles with multiple orifices 0.12mm and hole spacing 1.0mm
/ cm ² , second row 70 kg / cm ² , third row 110 kg / cm ² while injecting a high-pressure water stream, entanglement treatment is performed at a speed of 50 m / min, followed by drying to obtain a reinforced nonwoven fabric. It was The results of measuring the physical properties are shown in Table 1. As Comparative Example 1, only the rayon short fiber web (A ₁ ) used in this example was subjected to high pressure water flow treatment under the same basis weight conditions as in this example to obtain a nonwoven fabric. The results are also shown in Table 1. From these results, the reinforced non-woven fabric of the present invention has a significantly higher strength than the non-woven fabric composed of only the short fiber web, and the strength ratio in the machine direction and the cross direction is close to 1, and the balance of strength is improved. You can see that

<Example 2, Comparative Example 2> As a web layer, the fineness and length of the fiber are 2d × 45 mm, and the basis weight is 30 g / m ^2.
The same process as in Example 1 was carried out except that the polypropylene short fiber (A ₂ ) was used. In Comparative Example 2, a polypropylene short fiber web (A ₂ ) was used and treated in the same manner. The results are shown in Table 1.

<Example 3, Comparative Example 3> As a web layer, the fineness and length of the fiber are 2d × 45 mm, and the basis weight is 30 g / m ^2.
The same treatment as in Example 1 was carried out except that the short nylon fiber (A ₃ ) was used. Comparative Example 3 is a nylon short fiber web (A
_It was processed in the same manner using only ₃ ). The results are shown in Table 1.

<Example 4, Comparative Example 4> As a web layer, the fineness and length of the fiber are 2d × 45 mm, and the basis weight is 30 g / m ^2.
Example 1 except that the polyester short fiber (A ₄ )
The same process was carried out. Comparative Example 4 was treated in the same manner using only the polyester short fiber web (A ₄ ).
The results are shown in Table 1.

<Example 5 and Comparative Example 5> A nonwoven fabric using a polyethylene uniaxially oriented body having a basis weight of 31 g / m ^{2 as} the web layer made of the polyester short fibers (A ₄ ) used in Example 4 (trade name: Nisseki Wallif MS-T, Nisseki Plast Co., Ltd.
The same treatment as in Example 1 was carried out except that the reinforcing support layer made of (B ₂ ) was entangled. In Comparative Example 5, only the polyester short fiber web (A ₄ ) was used and treated under the same basis weight conditions as in Example 5. The results are shown in Table 1.

[0028]

The reinforced nonwoven fabric obtained by the present invention is
It has excellent tensile strength, especially vertical and horizontal tensile strength balance, peeling strength, flexibility, texture, drape property, lint-free property, etc., industrial materials such as filters and industrial wipers that utilize the reinforcing function, and surgical garments, Widely used for medical disposable products such as sheets, towels and masks.

[Brief description of drawings]

FIG. 1A is a partially enlarged perspective view of an example of a vertically uniaxially oriented reticulated film.

FIG. 2 (b) is a partially enlarged perspective view of an example of a laterally uniaxially oriented reticulated film.

FIG. 3 (c) is a partially enlarged perspective view of an example of a uniaxially oriented multilayer tape.

FIG. 4 is a partial plan view of an example of a nonwoven fabric.

FIG. 5 is a partial plan view of another example of a nonwoven fabric.

FIG. 6 is a partial perspective view of an example of a woven cloth.

FIG. 7 is a schematic view showing an example of a manufacturing process of the present invention.

[Explanation of symbols]

 1 longitudinal uniaxially oriented reticulated film 2 first thermoplastic resin layer 3 second thermoplastic resin layer 6 lateral uniaxially oriented reticulated film 7 uniaxially oriented multilayer tape 8, 9 non-woven fabric 10 woven fabric 11, 11 'web layer 11a, 11a 'Web layer supply roll 12 Reinforced support layer 12a Reinforced support layer supply roll 13 Transfer support 15 High-pressure water stream injector 15a Water stream 16 Water immersion device 17 Moisture suction device 18 Oven 19 Reinforced nonwoven fabric

[Table 1]

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[Procedure amendment]

[Submission date] January 17, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

<Example 5 and Comparative Example 5> A non-woven fabric using a polyethylene uniaxially oriented body having a basis weight of 31 g / m ^{2 as} the web layer made of the polyester short fibers (A ₄ ) used in Example 4 (trade name: The treatment was performed in the same manner as in Example 1 except that the reinforced support layer made of Nisseki Wallif MS-T and Nisseki Plast Co., Ltd. (B ₂ ) was entangled. In Comparative Example 5, only the polyester short fiber web (A ₄ ) was used and treated under the same basis weight conditions as in Example 5. The results are shown in Table 1.

[Table 1]

Claims (4)

[Claims] 1. The web layer and the reinforcing support layer are integrated by intertwining the fibers of the web layer made of short fiber type cellulosic fibers or synthetic fibers with the reinforcing support layer by a spunlace method. A reinforced non-woven fabric, wherein the reinforced support layer comprises a breathable oriented body. 2. The breathable alignment material comprises the following (a):
A thermoplastic resin non-woven fabric or a woven fabric obtained by laminating or weaving at least one kind of uniaxially oriented material selected from (b) and (c) such that the orientation axes intersect each other. Item 1. A reinforced nonwoven fabric according to item 1, (a) a longitudinal uniaxially oriented reticulated film, (b) a lateral uniaxially oriented reticulated film, (c) a uniaxially oriented multilayer tape. 3. A laminate formed by supplying and superimposing a web layer made of short-fiber cellulose-based fibers or synthetic fibers on one or both sides of a reinforced support layer made of at least one breathable orientation body. While transporting 30
~ 300kg / cm ² high-pressure water jet, processing speed 1-1
A method for producing a reinforced non-woven fabric, characterized in that the web layer and the reinforced support layer are integrated by performing an entanglement process at 50 m / min. 4. The breathable alignment material comprises the following (a):
A thermoplastic resin non-woven fabric or a woven fabric obtained by laminating or weaving at least one kind of uniaxially oriented material selected from (b) and (c) such that the orientation axes intersect each other. Item 3. A method for producing a reinforced nonwoven fabric according to Item 3,
(A) Vertical uniaxially oriented reticulated film, (b) Horizontal uniaxially oriented reticulated film, (c) Uniaxially oriented multilayer tape.