JPH0341584B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a three-layer ultrafine fiber nonwoven fabric.
More specifically, the present invention relates to an ultrafine fiber nonwoven fabric having a three-layer structure consisting of two web layers made of cellulose fibers and a web layer made of ultrafine fibers arranged between the two web layers. [Problems to be solved by the prior art and the invention] The fibers made of wood pulp and the aggregate made of synthetic organic fibers are treated with a thin columnar jet of water having an orifice supply pressure of at least 6900 Kpa. A method for obtaining spunlaced nonwoven fabric by intertwining fibers of
It is disclosed in Publication No. 94659. This nonwoven fabric is mainly suitable for medical applications (uses that take advantage of its bacterial barrier properties). However, when this nonwoven fabric is used as a packaging material after being sterilized, plasticizers, stabilizers, etc. contained in the synthetic fibers may be extracted during steam sterilization and come out on the surface of the fibers. Many of these plasticizers and stabilizers are harmful to the human body and have become a problem. Also E, O, G
When sterilizing with (ethylene oxide gas), synthetic fibers adsorb much more than cellulose, and there are problems in that it takes a long time to leave the fibers in order to reduce residual E, O, and G. In addition, a nonwoven fabric in which a layer of hydrophobic fine fibers is sandwiched between two layers of a composite material consisting of a low melting point component material and a high melting point component material, and is fused and integrated at a temperature lower than that of the high melting point material is disclosed in JP-A-Sho. It is disclosed in Japanese Patent No. 62-104954 and is said to be suitable for sterile packaging materials. However, since this composite nonwoven fabric is heat-sealed at 135°C to 145°C, low-melting components may harden during steam sterilization, and plasticizers and stabilizers contained in the fibers may be extracted during steam sterilization and appear on the fiber surface. There are problems such as coming. Also, as a wiper in the electronics field,
The two-layer nonwoven fabric of wood pulp and organic synthetic fibers disclosed in JP-A No. 59-94659 has a fibrillated wood pulp layer on the surface, so it has good liquid absorption properties, but it does not absorb well due to wear and friction. Fiber fluff and falling fibers are likely to occur. Therefore, there is a problem in that it is still unsatisfactory for use in clean rooms with high cleanliness. The present invention solves the above-mentioned problems of conventionally known nonwoven fabrics of this kind, and although it is a nonwoven fabric mainly composed of cellulose fiber web, it has high lint-free properties, abrasion resistance, and excellent water absorption and bacteria barrier properties. The purpose of the present invention is to provide a nonwoven fabric having characteristics such as elasticity. [Means for Solving the Problems] The above-mentioned object of the present invention is to provide two web layers made of long fibers or cellulosic fibers having a relatively long fiber length, and a web layer disposed between the two web layers. An ultrafine fiber nonwoven fabric with a three-layer structure consisting of a web layer made of ultrafine fibers, in which the fibers constituting each web layer of the nonwoven fabric are integrally intertwined with the fibers constituting other web layers. This is achieved by using a microfiber nonwoven fabric with the following characteristics. That is, in the nonwoven fabric according to the present invention, cellulose fibers are selected from which impurities are not extracted during steam sterilization, and the cellulose fibers have an extremely low Young's modulus in a wet state, and have the property of being easily moved by water flow and easily entangled with other fibers. Focusing on this point, the lint falling off from the ultrafine fiber web forming a dense layer is covered by sandwiching the web between the front and back surfaces of the web with cellulose fiber webs. Furthermore, the entire structure is integrated by intertwining the fibers. The three-layer ultrafine fiber nonwoven fabric of the present invention will be described in detail below based on an example shown in the drawings. FIG. 1 is a diagram schematically showing the state of the ultrafine fiber nonwoven fabric of the present invention before entanglement. In FIG. 1, and are web layers made of cellulose fibers, and are web layers made of ultrafine fibers. FIG. 2 is a schematic diagram showing an enlarged cross section of the ultrafine fiber nonwoven fabric of the present invention (magnification: about 60 times). In Figure 2, and is a web layer made of cellulose fibers, and is a web layer made of ultrafine fibers. These three web layers are stacked in a sandwich pattern, and the fibers intertwine with each other to form a structure. has been done. A part 1' of the constituent fibers of the web layer made of cellulose fibers 1 sticks between the ultrafine fibers 2 of the web layer made of ultrafine fibers 2, and a part is bent in all directions and intertwined with the ultrafine fibers 2. There is. Furthermore, some of the fibers 1'' are inserted into the web layer made of cellulose fibers, and some of them are bent in all directions and intertwined with the cellulose long fibers 1. In addition, cellulose fibers are inserted from both sides in the same manner as above. The nonwoven fabric may be integrated by penetrating the web layer of the ultrafine fiber nonwoven fabric of the present invention, entangling it, penetrating it, and sticking it to the web layer of cellulose fibers on the opposite side.The degree of integration of the ultrafine fiber nonwoven fabric of the present invention is measured by peel strength. The microfiber nonwoven fabric of the present invention having such a structure can be used in aseptic packaging materials that are sterilizable and require high lint-free properties, abrasion resistance, and excellent bacterial barrier properties, and can be used in clean rooms. The nonwoven fabric according to the present invention can be usefully used in wiping wipers that require high lint-free properties, high abrasion resistance, and excellent water absorption. The layers are integrated to such an extent that they do not peel off during bending or wiping.The cellulose fiber web layer used in the present invention is made of regenerated cellulose fibers such as Cupro ammonium rayon or viscose rayon, or cotton. A web made of natural cellulose fibers such as short fibers having a fiber length of 20 mm or more, preferably 28 mm or more, and more preferably consisting of substantially continuous long fibers may be used. If the fiber length is less than 20 mm, the abrasion resistance and lint-free properties targeted by the present invention cannot be achieved.The cellulosic fiber web layer may be formed by, for example, a web formed by aligning fibers with a card, or a web formed by wet paper making. It may be a paper-like web, or a wet sponbond nonwoven fabric, as long as the constituent fibers move with water flow.Furthermore, the fiber cross section may have an irregular shape such as a triangle or an I-shape.Next, the ultrafine fiber web layer is Synthetic polymers such as polyamide, polyester, polyacrylonitrile, and polypropylene or their copolymers, as well as fibers such as cuprammonium rayon and viscose rayon, with a thickness of 0.6 d or less are used.Special Examples of ultrafine fibers include fibrillated fibers, such as pulp, linter, beaten products of other natural fibers, and pulp-like particles of synthetic polymers.The length of ultrafine fibers is not particularly limited, but pulp etc., a thickness of 2 mm or more is suitable.
If it is less than 2 mm, the problem arises that the abrasion resistance and lint-free properties targeted by the present invention cannot be achieved. More preferably, it is 5 mm or more. Regarding the thickness of the fibers, there is a problem in that fibers with a thickness of 0.6 d or more cannot achieve the bacteria barrier properties that are the object of the present invention. In the case of synthetic fibers, a web can be formed by spinning fibers with uniform fineness by melt spinning.
Furthermore, in the case of Kyupura ammonium rayon, a fiber of 0.1 d can be spun by wet spinning.
(Refer to JP-A-51-70311) In addition, the beaten fibers are distributed from 0.01 d to 2 d, and it is sufficient if the average denier is 0.6 d or less. If the fiber is 0.6 d or more, the bacteria barrier properties will be poor as described above, and it is more preferable to use fibers with a diameter of 0.3 d or less. The ultrafine fiber web layer has a basis weight of 6 to 50 g/m ² . If it is less than 6 g/m ² , the bacteria barrier properties will be poor, and if it is more than 50 g/m ² , it will be too dense and have poor breathability. A more preferable range is 8 to
It is in the range of 40g/ ^m2 . The ultrafine fiber web layer can be formed by spinning using a normal melt spinning method, cutting and carding to form a web, or by spinning using a melt blow spinning method to form a web, or by wet spinning recycled fibers. It is possible to use a paper formed into a web, or a paper made by beating natural fibers. The ultrafine fiber nonwoven fabric of the present invention has the above-mentioned ultrafine fiber web layer sandwiched between cellulose long fiber web layers in a sandwich pattern, laminated, and integrally intertwined. It provides properties such as abrasion resistance, lint-free properties, bacterial barrier properties, and water absorption. Next, a method for manufacturing the ultrafine fiber nonwoven fabric of the present invention will be explained. When using a cellulosic fiber web, for example, a web made of cuprammonium rayon, this web has a structure formed by self-adhesion and light entanglement of the fibers, and can be rearranged by water flow, but is free from other fibers. When using a web made of PVA, CMC, or the like, it is preferable to use a web whose state is maintained using a water-soluble adhesive such as PVA or CMC. Next, a web made of an appropriate type of ultrafine fiber is prepared, and three layers are laminated by sandwiching the ultrafine fiber web. At this time, webs manufactured in different manufacturing processes may be laminated and manufactured in an off-line process, or the processes for manufacturing each web may be combined. For example, a process for producing a recycled fiber spunbond nonwoven fabric using a wet method and a process for producing a melt-blown nonwoven fabric may be combined. The lamination of three layers of web is shown in Figure 1.
A web made of ultrafine fibers is laminated between two layers of cellulosic long fiber web layers, and this is placed on a screen, and a high-pressure thin water jet is sprayed from above. Alternatively, the web may be reversed and subjected to water jet treatment. Screen mesh is usually 200
~100 are used. The jet pressure of the water jet is usually 25Kg/ ^cm2 or more, preferably 30Kg/ ^cm2.
More selected. If it is less than 25 kg/cm ² , satisfactory wet strength is often not obtained. After the treatment, it is dried to obtain an ultrafine fiber nonwoven fabric. The present invention utilizes the property that when the fibers constituting the cellulosic fiber web layer are wetted, they become fibers with an extremely low Young's modulus and are easily moved by water flow. As a result, the cellulose fibers are inserted into the ultrafine fiber web layer, packed and entangled with the fibers, and penetrated through the ultrafine fiber web layer and inserted into the cellulose fiber web layer on the opposite side, entwined with the fibers, and intertwined together. be done. If the web layer is further inverted and subjected to the water jet treatment described above, the same phenomenon as described above will occur, increasing the chance of intertwining of the fibers and making them even more integrated. [Example] The present invention will be explained in detail with reference to Examples below. Prior to describing the examples, the definitions and measurement methods of characteristic values used in the examples will be collectively shown. ◎Basic weight: Take three samples of 250 x 250 mm from the standard sample, and after reaching a moisture equilibrium state, measure the weight (g) and calculate the average value per unit area (g/m ² ). represent. ◎Water absorption rate: Take a 14.5 x 2.2 cm test piece from the sample,
Collect 3 pieces of one piece each in the vertical and horizontal directions, and make 20 pieces.
Hold it at a constant height above a beaker containing Hemacel at ±2°C and fasten it vertically with a clip. Next, the Hemacel was brought close to the test piece, and the water absorption height (mm) of the Hemacel was measured 1 minute after the contact, and the average value (mm) was expressed. ◎Water absorption: Cut the sample into 10 cm x 10 cm and weigh it (W ₁ ), sandwich this sample between 10 mesh wire mesh,
Soak in Hemacel solution for 5 minutes. Next, leave it on a wire mesh for 5 minutes, pick it up with tweezers for 30 seconds to remove excess hemacel, and weigh it (W ₂ ). W ₂ −W ₁ /W ₁ = (times) Expressed in water absorption capacity. ◎Strong elongation: Measured according to JIS-1068. Expressed in strength (Kg/5cm width) and elongation (%). ◎Abrasion resistance: Sample in standard condition, width 25mm x length
A 250mm piece was rubbed using a Gakushin type bending friction tester (manufactured by Shimadzu Corporation) under the conditions of a load of 200g and 50 frictions. After rubbing, accurately collect a small piece of 25 x 25 mm, approximately 2 g, and place it in an ultrasonic cleaner (Yamato, B220H).
Fill with 250 c.c. of water, wash for 15 minutes, remove the sample piece, collect the fallen lint on black paper, dry it, adjust the humidity, and measure its weight using a microbalance. The higher the lint (mg), the worse the wear resistance. ◎ Bacterial barrier property: The upstream and downstream concentrations of the test specimen are measured simultaneously with two detectors under a flow of monodisperse particles under certain conditions, and the dustproof rate (%) is determined. Stearic acid aerosol with an average diameter of 0.3 μm was used as the monodisperse particles. Flow rate is 2.1
cm/sec, and the measurement time was 1 minute. The measuring device is SIBATA Digital Dust Ingicator
Model AP-632 was used. Dust-proof rate (%) = (1-D ₂ /D ₁ )×100 D ₁ ; Upstream photo counter D ₂ ; Downstream photo counter The higher the dust-proof rate (%), the better the bacterial barrier property. ◎Peel strength: Measured according to JIS-1068. Strength (Kg/5cm width) Example 1 A web made of copper ammonia cellulose fiber (copper ammonia rayon) continuous filament (single yarn 1.5 d) according to the method for manufacturing recycled fiber spunbond nonwoven fabric described in Japanese Patent Publication No. 52-6381. was manufactured. Products with a basis weight of 8 g/m ² and 10 g/m ² were produced. Separately, described in Japanese Patent Application Laid-Open No. 51-67411,
A web made of ultrafine polyester fibers was produced according to the melt blowing spinning method. The single yarn fineness is 0.05d, and the basis weight is 5g/m ² , 6g/m ² , 8
g/m ² , 12 g/m ² and 20 g/m ² were produced. Next, the next ultra-fine fiber web was sandwiched between the previous two layers and laminated into three layers, placed on a 100-mesh screen, and treated by spraying a high-pressure thin jet of water from above. . At the same time, suction was drawn from the bottom of the screen. The web layer was also inverted and subjected to the water jet treatment described above. The processing conditions are shown below. Orifice diameter: 0.15 mmφ Processing density: 30 holes/cm x 5 times Processing pressure: 30 Kg/cm ² Processing speed: 5 m/min After the processing, it was dried through a drier to obtain an ultrafine fiber nonwoven fabric. Table 1 shows the combinations of webs and the characteristic values of the obtained microfiber nonwoven fabrics. As can be seen from Table 1, the dustproof rate of the ultrafine fiber web with a basis weight of 5 g/m ² is 2.2%, which is 10.1% of the conventional product.
It can be seen that if it is 6 g/m ² or more, it is possible to manufacture products that are equivalent to or higher than conventional products. Furthermore, these products of the present invention have water absorption properties and wet strength close to those of conventional products. What is noteworthy is that the ultra-fine fiber web with a basis weight of 20g/m ² and a total basis weight of 40g/m ² exhibits a dustproof rate of 46.0%, which is four times better than conventional products.
The product of the present invention can be formed thinly and can be said to have excellent bacteria barrier properties. Furthermore, it can be seen that the wear resistance of the product of the present invention is about three times better than that of the conventional product after wear. Moreover, the peel strength shows such a value that when used in a wiper for wiping, each layer does not peel off during bending or wiping during use. Furthermore, another web made of copper ammonia rayon continuous filament with a basis weight of 10 g/m ² and a web made of ultrafine polyester fiber with a basis weight of 20
g/m ² was selected, and among them, copper ammonia rayon web was dyed under the following conditions. Copper ammonia rayon web dyeing, paint: Kayarus Supra Red 6BL (Nippon Kapowder KK product) Dyeing: 3% owf Bath ratio 1:50 Temperature rise: 30 minutes Room temperature to 90℃ 90℃ Washing with water for 45 minutes; Color fixing for 5 minutes ; Amigen (Daiichi Kogyo Seiyaku KK product) 0.2% Bath ratio 1:50 After immersing for 10 minutes, dehydrate and dry. Then, sandwich the next ultrafine fiber web between two layers of copper ammonia rayon web to make three layers. Confounding processing was performed according to the conditions described earlier, and after processing,
After drying, an ultrafine fiber nonwoven fabric was obtained. When the cross-section of this nonwoven fabric was observed under a microscope, it was found that the red-dyed copper ammonia rayon fibers penetrated into the white polyester ultrafine fiber web layer and were intertwined with each other, as described in detail above. was able to be observed. Example 2 Among the webs made of copper ammonia cellulose fiber continuous filament (single yarn 1.5 d) used in Example 1, one with a basis weight of 10 g/m ² was used. Also, among the webs made of ultrafine polyester fibers used in Example 1, one with a basis weight of 20 g/m ² was used. Separately, a random card web of viscose rayon staple fiber (single yarn 2d, fiber length 51 mm) with a basis weight of 15 g/m ² was prepared. These webs were laminated with a polyester ultrafine fiber web with the viscose rayon staple fiber web facing down, and then a copper ammonia cellulose fiber continuous filament web was laminated thereon, and treated according to Example 1 to obtain an ultrafine fiber nonwoven fabric. was manufactured. The characteristic values are shown in Table 1. As can be seen from the table, the water absorption and wet strength are on par with conventional products, but despite being thin with a basis weight of 45 g/ ^m2 , the dustproof rate is 51.7%, which is five times higher than conventional products, and the wear resistance is also low. I know it's excellent. Example 3 Among the webs made of copper ammonia cellulose fiber continuous filament used in Example 1, the fabric weight was 10.
g/m ² was used to form two layers, a sufficiently beaten pulp sheet (fabric weight 20 g/m ² ) was sandwiched between the two layers, and treated according to Example 1 to obtain an ultrafine fiber nonwoven fabric. The characteristic values are shown in Table 1. As can be seen from the table, the water absorbency and dustproof rate are on par with conventional products, but the abrasion resistance is slightly superior.

【table】

[Table] Example 4 In this example, the fineness of the ultrafine fibers was changed and the relationship with the dustproof rate was examined. The copper ammonia cellulose fiber (copper ammonia rayon) continuous filament web used in Example 1 was prepared. Separately, a web was produced by spinning ultrafine polyester fibers using a melt spinning method. At that time, the fineness of the fibers was changed to 1.0d, 0.6d, and 0.3d, and webs of each denier were produced by spinning. Then, the ultrafine fiber web was sandwiched and laminated into three layers, each having a different denier.
It was processed according to the processing conditions of Table 2 shows the characteristic values of the ultrafine fiber nonwoven fabric for each denier. Further, the characteristic values in the case of using a web of ultrafine fibers of 0.05 d are those of Example 1. As can be seen from Table 2, the fineness of the ultrafine fiber is 1.0d.
The dustproof rate of this product is 3.9%, which is much lower than the 10.1% dustproof rate of the conventional product described in Example 1.
7.8%, indicating that it is possible to manufacture products close to conventional products. Also, 0.3d is 10.6%, 0.05d
It is found that the fineness of the ultrafine fiber is 0.6d or less, which is as high as 13.8%. Example 5 Copper ammonia cellulose fibers (copper ammonia rayon) were spun using a falling tension spinning method to obtain 15
Four types of staple fibers (single yarn 1.6d, basis weight
20g/ ^m2 ). In addition, using the ultrafine yarn spinning device disclosed in Japanese Patent Application Laid-open No. 70311/1983, a large number of copper ammonia cellulose fibers each having a single yarn of 0.1 d were spun.
A web of g/m ² was produced. Then, a microfiber web was sandwiched between each of the four types of webs and laminated in three layers, and treated with a high-pressure thin water jet according to Example 1. Table 2 shows the characteristic values of the obtained ultrafine fiber nonwoven fabric. As can be seen from the table, the fiber length of 15 mm has a low wet strength of 1.1 kg/5 cm width, a low dustproof rate of 3.3%, and a low peel strength of 110 g/5 cm width.
It can be seen that if the fiber length is 20 mm or more, each characteristic value can be formed close to that of conventional products.

【table】

〔Effect of the invention〕

The microfiber nonwoven fabric of the present invention has water absorption and hygroscopicity comparable to conventional products, and has excellent effects such as high lint-free property, that is, abrasion resistance, and excellent bacteria barrier properties (dustproof properties) that cannot be obtained with conventional products. This makes it possible to provide a composite nonwoven fabric suitable for applications in the medical and electronics fields. The ultrafine fiber nonwoven fabric of the present invention is useful as a packaging material in the medical field. No impurities are extracted during steam sterilization, which is excellent for hygiene. Furthermore, even after E, O, G sterilization, no E, O, G remains. It also has excellent water absorption and high lint-free properties, making it useful as wipers in the electronics field.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically illustrating the state of the ultrafine fiber nonwoven fabric of the present invention before entanglement, and FIG. 2 is an enlarged cross-sectional view of the ultrafine fiber nonwoven fabric of the present invention (magnification: approximately 60
times). and...a web layer made of cellulose long fibers,...a web layer made of ultrafine fibers, 1,
1', 1'', 1... cellulose long fiber, 2...
Ultra-fine fiber.

Claims (1)

[Claims] 1 Ultrafine fibers with a three-layer structure consisting of two web layers made of long fibers or cellulose fibers with relatively long fiber length, and a web layer made of ultrafine fibers arranged between the two web layers. An ultrafine fiber nonwoven fabric characterized in that the fibers constituting each web layer of the nonwoven fabric are integrally intertwined with the fibers constituting other web layers.