JPH09111633A - Method for manufacturing meltblown nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production process for melt-blown non-woven fabrics excellent in water absorption properties and having a good fabric hand useful for wiper for a clean-room and industrial wiper by allowing the fibers constituting the non-woven fabric to uniformly and effectively contain a hydrophilizing agent. SOLUTION: This is a production process for a melt-blown non-woven fabric where the molten thermoplastic resin is extruded from the nozzle of a spinning machine thinned into micro fibers simultaneously, the extruded fibers are collected and accumulated to give a non-woven fabric, while the molten thermoplastic resin extruded from the nozzle, thinned, bonded and collected to form a web, the aqueous solution of a surfactant is sprayed with a two-fluid spray nozzle to the thread on the spinning line to quench the thread and giving the fibers hydrophilic properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing a nonwoven fabric suitable for wipers such as cleanroom wipers and industrial wipers.

[0002]

2. Description of the Related Art A manufacturing process of a melt blown nonwoven fabric is a spinning process in which a thermoplastic resin is melted and extruded from a nozzle, and at the same time, a molten resin obtained by high temperature and high speed air is thinned in the vicinity of the nozzle to form ultrafine fibers. And a collection step of forming the nonwoven fabric by accumulating the ultrafine fibers on a collection support in a state where the ultrafine fibers are not completely solidified yet and have a fusion property. The melt blown nonwoven fabric has a bulky and soft texture because the molten resin injected from the nozzle is thinned and is appropriately solidified while reaching the collection surface, and the constituent fibers are partially fused to each other during that time. . Therefore, in order to obtain a more bulky and flexible meltblown nonwoven fabric, the injected molten resin is sufficiently thinned to become ultrafine fibers until it reaches the collecting surface, and to the extent that it can be appropriately solidified. Since it was necessary to discharge the amount of resin, the amount of molten resin discharged per unit of nozzle hole was naturally limited.

That is, if the amount of the molten resin discharged is too large, it will not be sufficiently thinned by the time it reaches the collecting step, the rigidity of the resulting constituent fibers themselves will be high, and fibers that are not sufficiently cooled will be collected. Since the self-fusion between the constituent fibers becomes too strong to reach the surface, only a hard-textured sheet can be obtained, and the insufficiently cooled fibers become resin particles and easily adhere to the fiber surface, and a sheet with many shot defects Will be. Therefore, in order to increase the discharge amount of the molten resin, even if the distance from the spinning process to the cooling process is increased and sufficient cooling can be obtained, fusion between the fibers on the spinning line becomes remarkable. A fiber web that has many rope-like defects in which the fibers are bound in the sheet, and the speed of the yarns when reaching the collection process becomes too small, and the air blows into the collection process. Since the force for pressing the sheet from above is insufficient, sufficient self-adhesion cannot be formed between the constituent fibers, and only a sheet with weak strength can be obtained.

The melt-blown non-woven fabric thus obtained is used as a filter, a mask or the like because the constituent fibers are ultrafine fibers, or by using a hydrophobic thermoplastic resin as a raw material, a water barrier. Property, that is, it has a barrier property against bacteria using a liquid medium, and because the constituent fibers are bonded by self-fusion of the fibers themselves, lint is less likely to occur during use, and it also has air permeability. It has been widely used as a medical base material for surgical gowns, bandages and the like. In addition, a non-woven fabric composed of ultrafine fibers has a small gap between the constituent fibers, and since high liquid absorption and wiping properties due to the capillary phenomenon between the fibers can be expected, the melt blown non-woven fabric can be used as it is, or as a surfactant, bactericide, etc. It is post-processed with various treatment agents and is suitable for use in oil adsorbents and wipers.

Utilizing the above-mentioned properties, meltblown nonwoven fabrics have been widely used in cleanroom wipers and industrial wipers which are required to have particularly high liquid absorbency and a small amount of lint generated. When using a melt blown non-woven fabric for the application of these wipers, a hydrophilic treatment with a surfactant is indispensable. However, since melt-blown non-woven fabric is composed of ultrafine fibers, the surface area of the fibers forming the non-woven fabric is significantly larger than that of conventional woven fabrics and non-woven fabrics. It was difficult to carry out the chemical conversion treatment. Conventionally, methods such as a gravure printing method, a spray method, a foam coating method and an impregnation method have been used as a hydrophilic treatment method for hydrophilicizing a base material such as a woven cloth and a nonwoven cloth. However, when applying these methods to make the meltblown nonwoven fabric hydrophilic, there are the following problems.

For example, when a hydrophilic treatment agent is applied by the gravure printing method to carry out the hydrophilic treatment, the amount of the aqueous solution containing the surfactant which can be applied to the surface of the non-woven fabric can be retained in the cup of the gravure roll. Did not migrate to the surface of the meltblown nonwoven fabric, so that the surfactant was not sufficiently spread over the surface of the constituent fibers, and as a result, it was difficult to impart the necessary hydrophilicity to the meltblown nonwoven fabric. In addition, when performing the hydrophilization treatment by the spray method, it is attempted to reduce the drying load after the hydrophilization treatment, increase the concentration of the aqueous solution containing a surfactant for efficient production, and perform the hydrophilization treatment with a small spray amount. As in the case of the gravure printing method, the surfactant is not sufficiently spread over the surfaces of the constituent fibers, and the necessary hydrophilicity cannot be obtained.

On the other hand, by decreasing the concentration of the surfactant used and increasing the spray amount to increase the coating amount, the surfactant aqueous solution can be spread over the entire meltblown nonwoven fabric, and sufficient hydrophilicity is imparted. However, since a large amount of water is contained in the melt blown nonwoven fabric, a great amount of energy is required to dry the nonwoven fabric. Similarly, when the hydrophilic treatment is performed by the foam coating method, as in the case of using the spray method, a large amount of an aqueous solution containing a surfactant is spread over the entire meltblown nonwoven fabric to impart desired hydrophilicity. A surfactant must be added, and as a result, a large amount of energy is required for the drying process after the hydrophilic treatment. When the hydrophilization treatment is performed by the impregnation method, it is possible to uniformly impart a predetermined hydrophilic property to the entire meltblown nonwoven fabric, but when the excess impregnating liquid is removed by squeezing with a press in the squeezing step after impregnation, the nonwoven fabric is Since it is crushed, the bulkiness of the resulting nonwoven fabric is impaired. Moreover, since the amount of the aqueous solution containing the surfactant attached to the meltblown nonwoven fabric by the impregnation method is as large as that of the spray method or the foam coating method, a great deal of energy is required to dry the nonwoven fabric after the hydrophilic treatment. Become.

[0008]

SUMMARY OF THE INVENTION In view of the above situation, the inventors of the present invention have earnestly studied on the efficient inclusion of a surfactant for imparting hydrophilicity to a meltblown nonwoven fabric, and as a result, a method for producing a meltblown nonwoven fabric has been found. In the spinning process, we focused on thinning the molten resin with high-temperature, high-speed air and cooling while fixing the fibers to each other, and we added a surfactant to the fibers that have been thinned and fixed and still have a considerable temperature. When the aqueous solution is sprayed with a two-fluid spray nozzle and the yarn is rapidly cooled, the amount of discharge is increased and the production amount is increased, and the hydrophilic agent is uniformly contained in the non-woven fabric even without a drying step, which is excellent. It has been found that the nonwoven fabric can be imparted with flexibility, water absorbency and oil absorbency, and the present invention has been completed. An object of the present invention is to spray an aqueous solution containing a hydrophilizing agent onto yarns on a spinning line to uniformly and efficiently include the hydrophilizing agent in the fibers constituting the non-woven fabric, which has excellent water absorption performance, good texture, and a clean room. It is an object of the present invention to provide a method for efficiently producing a meltblown nonwoven fabric which can be suitably used as a wiper such as a wiper for industrial use and a wiper for industrial use.

[0009]

According to the present invention, a thermoplastic resin is melted and extruded through a nozzle hole of an extrusion spinning machine, and at the same time, the molten resin is thinned to form ultrafine fibers, and the obtained fiber group is collected. In a method for producing a melt-blown non-woven fabric, which is collected and accumulated on a support to form a non-woven fabric, a yarn on a spinning line during which a molten resin discharged from the nozzle hole is thinned, fixed, and collected to form a web. A thin aqueous solution containing a surfactant is sprayed by a two-fluid spray nozzle while thinning and fixing are completed, and the yarn is rapidly cooled and hydrophilicity is imparted to the nonwoven fabric. A method for producing a meltblown nonwoven fabric.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a thermoplastic resin is discharged from a nozzle hole in an extrusion spinning machine and spun, and at the same time, high temperature air is blown at a high speed to be finely divided into ultrafine fibers, which are then fused together. The filaments are rapidly cooled by spraying an aqueous solution containing a surfactant onto the filaments before the filaments of the obtained filaments are fixed on the trapping support. Examples of the thermoplastic resin in the present invention include polypropylene-based thermoplastic resins such as polypropylene, polyethylene and ethylene-propylene copolymer, polyester-based thermoplastic resins such as polyethylene terephthalate and polybutylene terephthalate, and polyamide-based thermoplastic resins such as nylon. Can be selected and used from these. Among them, it is preferable to use a polyolefin-based thermoplastic resin, which has a soft texture of the obtained fiber and can be obtained at low cost, particularly a polypropylene resin which does not feel a slimy feel when gripped and has an excellent tactile sensation. JIS K- of the resin used
7210 The melt flow rate measured by the method described in Condition 14 is preferably 500 g / 10 minutes or more. When the melt flow rate is less than 500 g / 10 minutes, it is possible to manufacture a melt blown nonwoven fabric by reducing the discharge amount of the molten resin from the nozzle of the extruder.
However, if the amount of molten resin discharged is increased in order to produce a nonwoven fabric at a high speed, the fibers are not sufficiently thinned in the spinning process, and only a hard-textured sheet can be obtained.

In addition, the spinning temperature is set high in order to advance the thinning in the spinning process while the discharge amount of the molten resin is increased.
It is possible to take a method to increase the fluidity of the resin,
When the spinning temperature is raised, the thermal decomposition of the resin is promoted, and it becomes difficult to efficiently and stably produce a sheet having a good texture, which is not preferable. On the contrary, the melt flow rate of the resin to be used does not have to be as high as possible, and if the melt flow rate becomes too high, it will be difficult to manufacture and granulate the resin, and the extruder will also be used when manufacturing the meltblown nonwoven fabric. The conditions for uniformly ejecting the molten resin from the nozzle hole are strict, and it becomes difficult to stably manufacture the nonwoven fabric, which is not preferable. Therefore, the upper limit of the melt flow rate of the resin that can stably produce the meltblown nonwoven fabric is about 1200 g / 10 minutes. The spinning temperature when the molten resin is discharged from the nozzle hole of the extrusion spinning machine is appropriately selected and determined depending on the type of resin used, the melt flow rate, the device used, etc., for example, when using a polypropylene resin as a raw material, 240 ° C-3
A range of 00 ° C. is preferred. The spinning temperature in this case is 240
When the temperature is lower than 0 ° C, the fluidity of the molten resin discharged from the nozzle is insufficient, the fibers are not sufficiently thinned in the spinning process, and the resulting meltblown nonwoven fabric has a hard texture. On the contrary, if the spinning temperature exceeds 300 ° C., decomposition of the molten resin is likely to proceed and stable spinning is difficult, which is not preferable.

The distance from the nozzle to the collecting surface (hereinafter referred to as the collecting distance) can be appropriately selected depending on the discharge amount of the molten resin, the spinning temperature, and the density of the meltblown nonwoven fabric to be obtained.
That is, when the amount of molten resin discharged is increased or the spinning temperature is set to be high, the fiber sprayed from the nozzle is sufficiently thinned and a long collection distance is set in order to solidify appropriately. Even when trying to obtain a bulky meltblown nonwoven fabric, a long collection distance is required in order to appropriately reduce the velocity of the ultrafine fibers jetted from the nozzle and the hot air that conveys them. As described above, it is necessary to set the production conditions appropriately balanced to obtain the desired characteristics. However, in the present invention, most of the cooling effect of the yarn is obtained by droplets of the jetted aqueous solution of the surfactant reaching the yarn and evaporating, and the texture of the nonwoven fabric is also adsorbed on the fiber surface. The combination of properties does not have to be so exact, as a very smooth nonwoven fabric is obtained due to the effect of the surfactants mentioned above.

In the present invention, the conditions under which the obtained melt-blown nonwoven fabric can obtain the required bulkiness as a wiper may be mainly set, and the collection distance is preferably in the range of 250 to 500 mm. When the collection distance is less than 250 mm, the resulting meltblown nonwoven fabric becomes dense and lacks in bulkiness, resulting in insufficient liquid absorption when used as a wiper, which is not preferable. On the contrary, when the collection distance exceeds 500 mm, fusion between the fibers on the spinning line becomes remarkable,
The rope-like defects increase in the nonwoven fabric, and the speed of the yarn and the hot air accompanying the yarn when reaching the collecting surface decreases, and the strength of the resulting meltblown nonwoven fabric becomes weak.

Examples of the spray nozzle constituting the spraying device used in the present invention include a two-fluid spray and a one-fluid spray such as a full-cone spray, a hollow-cone spray, a flat spray, and the like. It is preferable to use a two-fluid spray capable of uniformly jetting the yarn and efficiently cooling the yarn by the compressed air jetted at the same time as the aqueous solution. One-fluid spray such as full-cone spray, hollow-cone spray, and flat spray sprays too much liquid from one nozzle and the resulting melt-blown nonwoven fabric is soaked in water, requiring a drying process after the collection process. Becomes Furthermore, since a large amount of aqueous solution is jetted onto the spinning line, the flow direction of the yarn discharged from the nozzle is disturbed, which causes deterioration of the basis weight profile of the obtained meltblown nonwoven fabric, which is not suitable for use.

The spray nozzle of the spray atomizer is preferably installed at a position 100 to 200 mm below the nozzle surface of the extrusion spinning machine. This position is 1 from the nozzle surface
When it is less than 00 mm, the yarn is sufficiently thinned, and the yarn is rapidly cooled before being fixed, and the obtained meltblown nonwoven fabric has a hard texture. Further, the aqueous solution sprayed from the spray nozzle of the spray atomizer reaches the nozzle surface of the extruder, and the temperature of the nozzle hole is changed, so that the properties of the meltblown nonwoven fabric obtained are not stable. Will end up. On the contrary, the spray nozzle of the spray atomizer is 2 mm from the nozzle surface of the extruder.
If it is installed at a position exceeding 00 mm, the surface of the yarn is cooled when it begins to cool, so cooling by spray spray cannot be efficiently performed, and the texture of the nonwoven fabric becomes hard.

In the spray nozzle of the above-mentioned spray spraying device, the resin is discharged from the nozzle of the extruder, spun, thinned by air, then fixed, and the spinning wire is taken until it reaches the support for collection. Plural units are installed parallel to the width direction and at right angles to the spinning line so that they can be sprayed uniformly.
This is appropriately determined depending on the size of the extruder, that is, the spinning width, the type of spray nozzle, the performance, and the like. The distance from the spinning line of the spray nozzle is preferably set within the range of 150 to 300 mm. When the distance from the spinning line is less than 150 mm, the compressed air sprayed from the spray nozzle of the spray atomizer strongly contacts and interferes with the yarn flowing on the spinning line, and deteriorates the basis weight profile of the resulting meltblown nonwoven fabric. Therefore, it is not preferable. On the contrary, if the distance from the spinning line exceeds 300 mm and the distance increases, the sprayed aqueous solution is sprayed over a wide range on the spinning line, which is not preferable. That is, in order to efficiently cool the yarn,
Immediately after the yarn has been sufficiently thinned, it is preferable to feed liquid and air into contact with the yarn for rapid cooling, but if the distance from the spinning line of the spray nozzle exceeds 300 mm, it is sprayed from the nozzle. Further, since the aqueous solution is sprayed over a wide range on the spinning line, it becomes difficult to efficiently quench the yarn, and it becomes impossible to obtain a melt-blown nonwoven fabric having a soft texture, which is not preferable. Further, the spray spraying device may be installed on the opposite side (upstream side) of the web conveying direction or on the web conveying direction side (downstream side). It can be installed in both.

The pressure of the compressed air injected from the two-fluid spray forming the spray atomizer is 0.5 to 2.0 k.
A range of g / cm ² is preferred. Compressed air pressure is 0.5 kg
If it is less than / cm ^2, it is difficult to atomize the aqueous solution containing the surfactant into fine particles, and the surfactant cannot be uniformly attached to the fiber surface, which is not preferable. On the other hand, if the compressed air pressure exceeds 2.0 kg / cm ² , the compressed air will come into strong contact with the yarn on the spinning line and interfere with it, deteriorating the basis weight profile of the resulting meltblown nonwoven fabric and cooling and solidifying by air. It is not preferable because the ultrafine fibers of (3) are fused to each other and rope defects are easily formed. The amount of the surfactant aqueous solution sprayed from the two-fluid spray nozzle is appropriately determined depending on the hydrophilicity to be obtained, the amount of molten resin discharged from the nozzle of the extruder, the degree of cooling required, etc. It can be adjusted so that the meltblown nonwoven fabric is in a dry state and has a soft texture and excellent hydrophilicity.

The type of surfactant used in the present invention is
Various known compounds can be used, for example, anionic surfactants such as carboxylates, sulfates, sulfonates and phosphates, primary amine salts, secondary amine salts, Cationic surfactants such as tertiary amine salts and quaternary ammonium salts, amphoteric surfactants of amino acid type, amphoteric surfactants such as betaine type amphoteric surfactant, polyethylene glycol type nonionic surfactant, polyvalent Examples thereof include nonionic surfactants such as alcoholic nonionic surfactants, which are appropriately selected from these and dissolved in water to obtain an aqueous solution containing the surfactant. As described above, the amount of the surfactant contained in the meltblown non-woven fabric obtained by spraying the aqueous solution containing the surfactant onto the yarns of the fiber group on the spinning line by the spray atomizer is 0.5 per weight of the non-woven fabric. It is adjusted in the range of up to 3.0% by weight. When the content of the surfactant is less than 0.5% by weight based on the weight of the nonwoven fabric, it becomes difficult to impart sufficient hydrophilicity to the meltblown nonwoven fabric, which is not suitable for wiper applications. On the other hand, when the content of the surfactant exceeds 3.0% by weight, the hydrophilicity as a wiper is sufficient, but when the large amount of liquid is wiped off, the surfactant is easily detached from the non-woven fabric, and the wiper is easily wiped off. It is not suitable for use as a wiper because foaming tends to occur.

In the present invention, the basis weight of the meltblown nonwoven fabric is determined by the amount of molten resin discharged from the nozzle and the moving speed (line speed) of the collecting surface, which is 20 to 200 g / m 2.
It is in the range of ² . When the basis weight of the non-woven fabric is less than 20 g / m ² ,
The thickness of the obtained wiper is insufficient and a sufficient amount of liquid absorption cannot be obtained, which is not preferable. In addition, the basis weight of the non-woven fabric is 200
If it exceeds g / m ² , the thickness of the obtained wiper becomes too large, and it becomes difficult to handle the wiper, which is not preferable. Melt blown nonwoven fabric according to the present invention, in order to improve the surface strength of the nonwoven fabric, appearance, ease of handling,
Embossing may be performed by a known heat embossing device or ultrasonic bonding device.

The most important point in the present invention is that the two-fluid spray nozzle of the spray atomizer is installed toward the spinning line between the nozzle of the extruder and the collecting surface, and the surfactant is placed in the direction perpendicular to the spinning line. By spraying an aqueous solution containing the above, the yarn is rapidly cooled and the non-woven fabric is rendered hydrophilic. By this process, it is possible to obtain a wiper base material that is rich in water absorption in one step, and the aqueous solution sprayed from the spray nozzle of the spray atomizer is a fiber obtained by discharging and spinning the resin from the extruder nozzle. No special drying device is required because it is evaporated by the heat of the yarns of the group and dried when collected on the collection support. In addition, the yarn on the spinning line is cooled by the aqueous solution containing the surfactant and the compressed air blown together with the aqueous solution by spraying, after being thinned and fixed and then rapidly cooled, so that the yarn discharged from the extruder nozzle is cooled. The problem of shortage is solved, so that the discharge amount of the molten resin in the extruder can be set high, and the production efficiency is significantly improved.

Furthermore, since the aqueous solution containing the surfactant is sprayed onto the individual yarns on the spinning line, the surfactant is evenly and uniformly attached to the surface of each fiber, and the hydrophilicity of the resulting meltblown nonwoven fabric is improved. It is remarkably improved and the water absorption is high. Further, in the known process for producing a melt-blown nonwoven fabric, even after the fibers reach the collecting surface, the nonwoven fabric is formed by mutual fusion of the fibers due to the hot melt adhesive force still remaining on the fiber surface. By cooling the fibers with an aqueous solution containing a surfactant and compressed air before they are webbed on the collecting surface, it is possible to weaken the melt adhesive force when the fibers reach the collecting surface. As a result, the adhesion of the fibers to each other is appropriately suppressed, and thus the obtained meltblown nonwoven fabric becomes very bulky and flexible. As described above, the present invention is a method for manufacturing a non-woven fabric by the melt blow method, in which the molten resin discharged from the spinner is thinned, at a right angle toward the spinning line where fibers are formed while adhering, by a two-fluid spray nozzle. A method for producing a melt-blown nonwoven fabric, characterized in that an aqueous solution containing an atomized surfactant is jetted together with compressed air to rapidly cool the yarn and impart excellent bulkiness and hydrophilicity to the resulting nonwoven fabric. The melt-blown nonwoven fabric having excellent water absorption and good texture can be efficiently produced with high productivity.

[0022]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, all percentages are by weight.

Example 1 A polypropylene resin having a known melt-blowing nozzle was used as a raw material of a polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in JIS K 7210 condition 14, and a collecting surface was provided from the nozzle. Distance to is 350
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at intervals of 1 mm in the width direction was used. The amount of molten resin discharged was 1.0 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 260 ° C. which is immediately blown at a high speed,
An aqueous solution containing a surfactant is made perpendicular to the spinning line (flow of the yarn) by a spray nozzle of a spray spraying device installed at a position below the spinning line and 200 mm upstream of the spinning line (a method opposite to the flow direction of the nonwoven fabric). The yarn was sprayed, quenched with the above aqueous solution and cold compressed air, and collected on a collecting surface moving at a speed of 12 m / min to obtain a melt blown nonwoven fabric having a basis weight of 75.8 g / m ² .

The spray spray device is a two-fluid spray
Four nozzles are arranged in the width direction at intervals of 150 mm.
Contains a surfactant sprayed by a spray spray device.
Aqueous solution is sodium dialkylsulfosuccinate
Anion-based surface active agent (brand name: Ne
Ocol SW-C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), with water to a concentration of 1%
It was used after diluting. Compressed air supplied to a two-fluid spray
Atmospheric pressure is 1.0 kg / cm ^TwoAnd an aqueous solution containing a surfactant
The spray amount of 1100 g / min per 1 m width
Was. The content of the surfactant was 1.1% based on the weight of the nonwoven fabric.
Was. The unit weight, thickness, and density of the obtained meltblown nonwoven fabric
Degree, tensile strength, texture, water absorption rate, water retention rate, oil absorption rate,
The oil retention rate was tested by the following test method, and the results are shown in Table 1.
did.

Test Method (1) Unit Weight The weight of 10 A4 size samples was measured and the weight per 1 m ² and g were calculated. (2) Thickness The thickness (μm) under a load of 2 KPa was measured according to JIS L1906. (3) Density The fabric weight was divided by the thickness and displayed in g / cm ³ . (4) Texture The texture was evaluated by sensory evaluation by 20 monitors. The monitor grasps the non-woven fabric by hand and judges the bulkiness, softness, feel of the surface of the sheet, etc., and expresses it with an evaluation of 0 to 5 points according to the following criteria, and the total points (100 points) The full score was expressed as a texture value. 5 points: Very good feel of the sheet 4 points: Excellent feel of the sheet 3 points: Normal feel of the sheet 2 points: Slightly poor feel of the sheet 1 point: Of the sheet Inferior to the touch 0 point: Very inferior to the feel of the sheet

(5) Tensile strength In accordance with JIS L 1906, the sample width was measured at 50 mm and displayed in g / 50 mm. (6) Water absorption rate (0.5 g of pure water was dropped from a height of 10 mm and the time (seconds) until it was absorbed in the sheet was measured to obtain the water absorption rate. (7) Water retention rate 100 mm × A sample cut to 100 mm is placed in pure water for 1
After soaking for 1 minute, it was taken out from pure water and drained in the air for 1 minute, and the water retention rate (%) was calculated from the total weight after draining and the sample weight before immersion in the equation (1). Water retention rate (%) = {(total weight after draining-weight of sample before immersion in water) / weight of sample before immersion in water} × 100 (1) (8) Oil absorption speed Other than using salad oil instead of pure water Was measured in the same manner as (6) Measurement of water absorption rate. (9) Oil retention rate Measurement was performed in the same manner as (7) Measurement of water retention rate except that salad oil was used instead of pure water.

Example 2 JIS K 7210 polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in Condition 14 of JIS K 7210 was used as a raw material resin, equipped with a known melt-blowing nozzle, and a collecting surface from the nozzle. Distance to 400
using an mm extruder at a spinning temperature of 280 ° C.,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at intervals of 1 mm in the width direction was used. The amount of molten resin discharged was 1.5 g / min per nozzle hole.

The yarn discharged from the nozzle of the extruder is
Immediately, it is sprayed at a high speed with heated air at a temperature of 300 ° C. to make it thin and fixed while flowing down toward the collecting surface, and 200 mm below the nozzle and 120 from the spinning wire.
An aqueous solution containing a surfactant is spun by the spray nozzles of a pair of left and right spray atomizers, which are installed at a position mm upstream and 200 mm below the nozzle, and 120 mm downstream (the flow direction of the nonwoven fabric) from the spinning line (flow of yarn). Sprayed at right angles to the above, the yarn was rapidly cooled from the front surface and the back surface with the aqueous solution and cold compressed air, accumulated on the collecting surface moving at a speed of 9 m / min, and melt-blown with a basis weight of 151.8 g / m ² . A non-woven fabric was obtained. The spray spraying device, spraying conditions, and type of surfactant are the same as those used in Example 1. The spray amount was 1100 g / min from each of the downstream and the upstream. Content of surfactant is 1.5 per weight of non-woven fabric
%Met. The nonwoven fabric obtained was tested in the same manner as in Example 1, and the results are shown in Table 1.

Example 3 Polypropylene resin having a melt flow rate measured by the method described in JIS K 7210 condition 14 of 700 g / 10 min was used as a raw material resin, equipped with a known melt-blowing nozzle, from the nozzle to the collecting surface. Distance is 400mm
Was melted and spun at a spinning temperature of 270 ° C. The melt-blowing nozzle used has a diameter of 0.3 m
m nozzle holes having a width of 500 mm installed at intervals of 0.8 mm in the width direction were used. The amount of molten resin discharged was 1.0 g / min per nozzle hole.

The yarn discharged from the nozzle of the extruder is
Immediately, it is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 270 ° C., which is 120 mm below the nozzle and 180 from the spinning wire.
mm spraying an aqueous solution containing a surfactant at a right angle to the spinning wire (flow of yarn) with a spray nozzle of a spray spraying device installed upstream (a method opposite to the flow direction of the non-woven fabric) and cold compressing the aqueous solution. The yarn is rapidly cooled with air and accumulated on the collecting surface that moves at a speed of 25 m / min.
A melt blown non-woven fabric of g / m ² was obtained. The spray atomizer has a two-fluid spray nozzle with a width of 100 mm.
An aqueous solution containing a surfactant sprayed by a spray spraying device is arranged at six intervals, and an anionic surfactant mainly containing dialkylsulfosuccinic acid sodium ester salt (trade name: Perex OT-P, (Made by Kao)
Was diluted with water to a concentration of 1.5% and used. The compressed air pressure supplied to the two-fluid spray was 1.5 kg / cm ² , and the spray amount of the aqueous solution containing the surfactant was 1300 g per 1 m width.
/ Min. The content of the surfactant was 1.6% based on the weight of the nonwoven fabric. The nonwoven fabric was tested in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 JIS K 7210 A polypropylene resin having a melt flow rate of 1,000 g / 10 min measured by the method described in Condition 14 was used as a raw material resin, and a known melt-blowing nozzle was provided. Distance to 450
using an mm extruder at a spinning temperature of 280 ° C.,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 3 mm and a width of 500 mm arranged at intervals of 0.8 mm in the width direction was used. The amount of molten resin discharged was 1.5 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 280 ° C. which is immediately blown at high speed.
50 mm below, 200 mm upstream from the spinning line and 150 mm below the nozzle, and the spinning line (flow of yarn)
The aqueous solution containing the surfactant is sprayed at right angles to the spinning line by the spray nozzles of the pair of left and right spray spraying devices installed at a distance of 200 mm downstream from each other, and the yarn is rapidly cooled with the aqueous solution and cold compressed air, and the speed is 18 m. The melt-blown non-woven fabric having a basis weight of 90.6 g / m ² was obtained by accumulating on the collecting surface moving at a speed of 1 / min.

In the above-mentioned spray atomizer, four two-fluid spray nozzles are arranged at intervals of 150 mm in the width direction, and the aqueous solution containing the surfactant atomized by the spray atomizer is dialkylsulfosuccinic acid sodium ester salt. An anionic surfactant (trade name: Perex OT-P, manufactured by Kao) whose main component is was diluted with water to a concentration of 2.0% and used. The compressed air pressure supplied to the two-fluid spray was 0.7 kg / cm ² , and the spray amount of the aqueous solution containing the surfactant was 1300 g / min per 1 m of width. The content of the surfactant was 2.8% based on the weight of the nonwoven fabric.
The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Example 5 A meltblown nonwoven fabric obtained in the same manner as in Example 1 except that the basis weight was set to 79.6 g / m ² was heated with a pair of heated embossing rolls and a smooth roll. It was introduced into an embossing device and embossed. A large number of circular protrusions having a diameter of 0.6 mm were arranged on the embossing roll, and the surface temperatures of the embossing roll and the smooth roll were both 110 ° C. The area of the heat-bonded portion formed on the melt-blown nonwoven fabric by this embossing was 7.3 area% of the area of the entire nonwoven fabric. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Example 6 A meltblown nonwoven fabric obtained in the same manner as in Example 1 except that the basis weight was 77.3 g / m ² was used, and one embossing roll and ultrasonic waves arranged in the width direction were used. It was introduced into an ultrasonic embossing device composed of a horn and embossed. The embossing roll had a large number of circular protrusions having a diameter of 0.6 mm arranged therein. The area of the bonded portion formed on the melt-blown nonwoven fabric by this embossing was 7.3 area% of the area of the entire nonwoven fabric. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Comparative Example 1 Polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in JIS K 7210 Condition 14 was used as a raw material resin, equipped with a well-known melt-blowing nozzle, and a collecting surface from the nozzle. Distance to 400
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at 1.0 mm intervals in the width direction was used. The amount of molten resin discharged was 0.5 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 260 ° C which is immediately blown at a high speed, and the collecting surface moves at a speed of 6 m / min. The melt-blown nonwoven fabric having a basis weight of 71.5 g / m ² was obtained by accumulating on the above. This non-woven fabric was impregnated with an anionic surfactant containing sodium dialkylsulfosuccinate as a main component (trade name: Neocor SW-C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) in an amount of 1.0% by weight of the non-woven fabric. And then dried to obtain a melt blown nonwoven fabric. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Comparative Example 2 Polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in JIS K 7210 condition 14 was used as a raw material resin, equipped with a well-known melt-blowing nozzle, and a collecting surface from the nozzle. Distance to 400
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at 1.0 mm intervals in the width direction was used. The amount of molten resin discharged was 0.8 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air which is immediately blown at a high temperature of 260 ° C, and the collecting surface moves at a speed of 10 m / min. The melt-blown nonwoven fabric having a basis weight of 75.5 g / m ² was obtained by accumulating on the above. This non-woven fabric was impregnated with an anionic surfactant containing sodium dialkylsulfosuccinate as a main component (trade name: Neocor SW-C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) in an amount of 0.1% based on the weight of the non-woven fabric. Was applied, and the excess amount of impregnation was pressed and squeezed to remove, and then dried to obtain a meltblown nonwoven fabric. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Comparative Example 3 Polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in JIS K 7210 condition 14 was used as a raw material resin, equipped with a well-known melt-blowing nozzle, and collecting surface from the nozzle. Distance to is 350
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at intervals of 1 mm in the width direction was used. The amount of molten resin discharged was 1.0 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 260 ° C. which is immediately blown at a high speed,
mm below and 200 mm upstream from the spinning line, an aqueous solution containing only water is sprayed at a right angle to the spinning line by a spray nozzle of a spraying device, and the yarn is rapidly cooled with the aqueous solution and cold compressed air. The melt-blown non-woven fabric having a basis weight of 79.5 g / m ² was obtained by accumulating on the collection surface moving at a speed of 12 m / min.

The spray atomizer has four two-fluid spray nozzles arranged at intervals of 150 mm in the width direction, and the aqueous solution containing only water atomized by the spray atomizer has a compressed air pressure of 1.0 kg / cm ² . , 1100 g / min per 1 m width. To this non-woven fabric, an anionic surfactant (trade name: Neocor SW-, whose main component is sodium dialkylsulfosuccinate) is used.
C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was applied by an impregnation method so as to be 5.0% based on the weight of the nonwoven fabric, and the excess impregnated amount was pressed and squeezed to remove it, followed by drying to obtain a meltblown nonwoven fabric. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1. When the obtained non-woven fabric was wiped off, foaming was observed.

Comparative Example 4 JIS K 7210 A polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in Condition 14 was used as a raw material resin and equipped with a known melt-blowing nozzle. Distance to is 350
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
A nozzle having a width of 4 mm and a width of 500 mm arranged at intervals of 1 mm in the width direction was used. The amount of molten resin discharged was 1.0 g / min per nozzle hole. The yarn discharged from the nozzle of the extruder is thinned and fixed while flowing down toward the collecting surface with heated air at a temperature of 260 ° C., which is immediately blown at a high speed.
mm below and 200 mm upstream from the spinning line, an aqueous solution containing only water is sprayed at a right angle to the spinning line by a spray nozzle of a spray atomizer, and the yarn is rapidly cooled with the aqueous solution and cold compressed air. The melt-blown nonwoven fabric having a basis weight of 77.2 g / m ² was obtained by accumulating on the collection surface moving at a speed of 12 m / min.

The spray atomizer has four two-fluid spray nozzles arranged at intervals of 150 mm in the width direction, and the aqueous solution containing only water atomized by the spray atomizer has a compressed air pressure of 1.0 kg / cm ² . , 1100 g / min per 1 m width. To this non-woven fabric, an anionic surfactant (trade name: Neocor SW-, whose main component is sodium dialkylsulfosuccinate) is used.
C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) was applied by a gravure coating method so as to be 1.5% based on the weight of the nonwoven fabric, and then dried to obtain a melt blown nonwoven fabric. The gravure roll used is 1
At 20 mesh, the cup depth was 60 μm. The nonwoven fabric obtained in the same manner as in Example 1 was tested, and the results are shown in Table 1.

Comparative Example 5 Polypropylene resin having a melt flow rate of 1,000 g / 10 min as measured by the method described in JIS K 7210 condition 14 was used as a raw material resin, equipped with a known melt-blowing nozzle, and a collecting surface from the nozzle. Distance to is 350
melt at a spinning temperature of 260 ° C. using an mm extruder,
Spun The melt-blowing nozzle used had a diameter of 0.
4 mm nozzle holes were used at 1 mm intervals in the width direction. The discharge amount of the molten resin is the nozzle hole 1
It was 1.0 g / min per piece. The yarn discharged from the nozzle of the extruder is immediately sprayed at high speed at a temperature of 2
Thinning and fixing are performed while flowing down toward the collecting surface with heated air at 60 ° C., and only water is contained by a spray nozzle of a spray atomizer installed 150 mm below the nozzle and 200 mm upstream from the spinning wire. A melt-blown non-woven fabric having a basis weight of 78.5 g / m ² is obtained by spraying the aqueous solution at right angles to the spinning line, quenching the yarn with the aqueous solution and cold compressed air, and accumulating on the collecting surface moving at a speed of 12 m / min. Got

In the spray atomizer, four two-fluid spray nozzles are arranged at intervals of 150 mm in the width direction, and the aqueous solution containing only water atomized by the spray atomizer has a compressed air pressure of 1.0 kg / cm ² . , 1100 g / min per 1 m width. To this non-woven fabric, an anionic surfactant (trade name: Neocor SW-, whose main component is sodium dialkylsulfosuccinate) is used.
(C, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) is diluted with water to 1.0%, and the foaming ratio is adjusted to 20 times by stirring, and the hydrophilic agent is attached by the foam coating method so that the ratio becomes 1.0% based on the weight of the nonwoven fabric. After that, it was dried to obtain a melt blown nonwoven fabric. The nonwoven fabric obtained was tested in the same manner as in Example 1, and the results are shown in Table 1.

[0043]

[Table 1]

As is clear from Table 1, according to the present invention, it is not necessary to dry the nonwoven fabric after adding the aqueous solution containing the hydrophilizing agent, and the yarn can be effectively cooled. Compared with 1), the discharge amount of resin can be increased (1.0 g / min / hole or more), and the production amount can be increased. In addition, the nonwoven fabric of the present invention has a low density, an excellent texture, and an excellent water absorption rate, water retention rate, oil absorption rate, and oil absorption rate. On the other hand, when the discharge amount is increased by a known method (Comparative Example 2), insufficient cooling of the yarn occurs, resulting in a non-woven fabric having a poor texture. After discharging the resin, the yarn is cooled by spraying an aqueous solution containing only water (Comparative Examples 3, 4 and 5).
Although the discharge amount can be increased, if the hydrophilic agent is added to the nonwoven fabric by the impregnation method later, the squeezing operation of squeezing and removing the excess impregnating liquid after the impregnation is performed, so that the density of the resulting nonwoven fabric is reduced. It becomes high and the texture is inferior (Comparative Examples 2 and 3).

In this case, when the content of the hydrophilizing agent is lowered, the degree of squeezing becomes relatively large, so that the texture of the obtained nonwoven fabric is remarkably deteriorated and the water absorption is remarkably poor (Comparative Example 2). On the other hand, if the content of the hydrophilizing agent is large, the degree of squeezing can be small, and the texture does not become extremely bad (Comparative Example 3). On the contrary, since the hydrophilizing agent is too much, the nonwoven fabric is used. It is not suitable for practical use because foaming occurs when it is wiped off. When the method for containing the hydrophilizing agent is a coating method such as gravure printing (Comparative Example 4) or foaming method (Comparative Example 5), the hydrophilizing agent cannot be uniformly attached to the entire fibers of the non-woven fabric, resulting in a water absorption rate. Will be inferior. The present invention
As described above, the melt-blown non-woven fabric containing the hydrophilizing agent is a method of producing it with a large discharge amount and without performing drying after the hydrophilizing treatment. And the manufacturing method can be simplified.

[0046]

INDUSTRIAL APPLICABILITY The present invention sprays an aqueous solution containing a surfactant with a two-fluid spray nozzle toward a spinning line on which molten resin injected from a die of an extruder is thinned and solidified to form fibers. By rapidly cooling the yarn, the discharge amount is increased to increase the production amount, and without using a drying process, it is bulky and has excellent flexibility, as well as excellent water absorption and oil absorption, for clean room wipers and industrial It is effective to provide a method for producing a meltblown nonwoven fabric suitable for use as a wiper such as a wiper.

Claims (1)

[Claims] 1. A thermoplastic resin is melted and extruded through a nozzle hole of an extrusion spinning machine, and at the same time, the molten resin is thinned to form ultrafine fibers, and the obtained fiber group is collected and accumulated on a collecting support. In the method for producing a melt-blown nonwoven fabric, the molten resin discharged from the nozzle hole is thinned, fixed, collected and collected toward the yarn on the spinning line during web formation and fixation. The method for producing a meltblown nonwoven fabric, characterized in that, while being completed and collected, an aqueous solution containing a surfactant is sprayed by a two-fluid spray nozzle to quench the yarn and impart hydrophilicity to the nonwoven fabric.