JPS6022100B2 - Manufacturing method of nonwoven fabric - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves continuously feeding molten thermoplastic resin into paper threads through edge thread holes, and at the same time discharging gas at high speed from gas discharge holes installed adjacent to the bush thread holes. The present invention relates to an improved method for producing non-sprayed fabrics, which comprises drawing threaded thermoplastic resin fibers, forming a fiber stream consisting of the fibers and the gas, and then collecting the fiber stream.

More specifically, a method for producing a nonwoven fabric with good feel and no pinholes by bringing the fiber stream into contact with fine droplets and then collecting the fibers, and
), relates to a method for producing non-sprayable fabrics made of a resin with a slow curing rate, such as thermoplastic polyurethane. A method of producing nonwoven fabrics by making thermoplastic resin into molten paper threads and then spraying and collecting them as fine fibers on a horizontal collector board that is moving with high-speed gas is known as the melt-blowing method (Tokukan Sho 491). Publication No. 102, JP-A-49-489
Melt-blowing PrMes
(see Japanese Patent Publication No. 44-25871, Japanese Patent Publication No. 44-25871, Japanese Patent Publication No. 44-25871)
(Refer to Japanese Patent No. 126977).

The nonwoven fabrics obtained by these methods have a diameter of 0.5~
It is a porous non-woven fabric made of 20mm fibers, and its pore diameter can be set within a wide range depending on the purpose.
Lead-acid battery polar plate separators, filter materials, medical masks,
It is used for applications such as artificial leather and adhesives.

However, when thin nonwoven fabrics are produced using conventional methods, not only do pinholes occur and the product value decreases, but also parts that are completely unusable are created, making it difficult to obtain long products. there were.

Furthermore, resins such as polyamide (especially Nine 12), thermoplastic polyurethane, etc. that have a slow curing speed or have high adhesiveness (blocking properties) can cause the sprayed fibers to fuse, so the conventional method cannot be used. Manufacturing nonwoven fabrics has been extremely difficult. The inventors of the present invention have conducted extensive studies on the causes of pinholes that occur when manufacturing thin nonwoven fabrics and methods for preventing their occurrence. Depending on the cause, bead-shaped parts may occur in the middle of the fibers, or particles that do not become fibers and are deposited near the shark thread holes are blown onto the collection slope with high-speed gas, and the heat dissolves the surrounding fibers. The present invention was developed based on the discovery that the generation of pinholes due to the above-mentioned causes can be prevented by bringing the fiber stream into contact with fine droplets and then collecting them.

In addition, by using the method of the present invention, polyamide (especially nylon 12) and thermoplastic polyurethane, which have been extremely difficult to manufacture, have a slow curing speed and are sticky (
They have discovered that it is also possible to produce nonwoven fabrics from resins that have blocking properties. That is, the gist of the present invention is to continuously spin a molten thermoplastic resin through a plurality of paper yarn holes installed in a spinning device, and at the same time to release gas from a gas discharge hole installed adjacent to the spinning holes. The thermoplastic resin is discharged at high speed to draw the fibers and form a fiber stream consisting of the fibers and the gas, and then the fiber stream is collected at a portion where the fibers are sufficiently drawn and are not completely solidified. A method for producing a nonwoven fabric made of the fibers by spraying the fibers onto a slope, which involves bringing the fiber stream into contact with fine droplets and then spraying the fibers onto a citrus board and collecting the fibers in a bottle.

The thermoplastic resin used in the method of the present invention includes:
Homopolymers of Q-olefins such as ethylene or propylene, butene-1,4-methylbentene-1,
A copolymer or a mixture of these polymers, or a homopolymer, a copolymer of Q olefin, or a mixture of these polymers is added with various unsaturated monomers such as maleic anhydride,
Modified polyolefins grafted with hymic anhydride, acrylic acid or their esters, homopolymers, copolymers of the above Q-olefins, or mixtures of these polymers with modified polyolefins, polyamides such as nylon 6, nylon 66, nylon 6, 12, nylon 12, nylon 11, nylon 610 (both trade names or common names) or mixtures thereof, polyester,
Examples include polyethylene glycol terephthalate, polybutylene glycol, terephthalate or mixtures thereof, thermoplastic polyurethane, polystyrene, polymethyl acrylate, asphalt, pitch, etc., but polyolefin, polyamide, polyester, thermoplastic polyurethane, and pitch are particularly preferred. It is. The present invention may also use resins with slow curing speed and adhesiveness (blocking properties) such as nylon 12, nylon 6,12, and thermoplastic polyurethane. In addition, the grade yarn die used in the present invention is a die with spinning holes arranged in a ring or a straight line, but dies with paper yarn holes installed in a straight line, such as those described in Tokokukan Sho 49-10258, Kaisho 49-489
No. 21, Jikai Sho 50-121570, Hakama Yami Sho 50-46972, Samurai Ko Sho 44-25871, Japanese Patent Publication Sho 44-26977, and Japanese Patent Application Laid-open Sho 51-67.
Any die having the structure described in Publication No. 411 can be used, but in particular, Samurai Kosho No. 44-25871, Samurai Seki No. 49-48921, and JP-A No. 51-6741 can be used.
A die having the structure described in Publication No. 1 is preferred.

Next, as the cord collecting plate used in the present invention, metal or synthetic resin sheets, films, thin plates, woven fabrics, non-woven fabrics, nets or perforated plates made by weaving, punching, or other methods can be used. . In particular, the shape of the collection plate is a hollow cylinder,
Preferably, it is a ring or band-shaped net or perforated plate wrapped around a simply cylindrical drum or roll, or a woven or non-woven fabric wrapped around the surface thereof. In addition, the shape of the part on the collecting slope where the fiber stream is sprayed may be simply a flat part, but in particular, the collecting plate having a large number of through holes and the holding plate having a large number of through holes may be movable, and
The collecting plate and the holding plate are in contact with each other via a connecting fiber, and
In a fiber collecting section installed in such a way that the gap between the surfaces of the collecting plate and the presser plate in the direction opposite to the moving direction of the bottle collecting plate from the contacting part increases as the distance from the contacting part increases, It is particularly preferable to set the distance from the contact portion to within 5 times the distance of the fiber stream on the fiber stream on the orange board, since a uniform nonwoven fabric can be obtained and there will be less scattering of the fibers. Specific examples of the collection plate and presser plate of the fiber collection unit that satisfy these conditions include: '1) Either or both of the collector plate and the presser plate have a hollow cylindrical shape; , if at least one part of the fiber collecting part is a hollow cylindrical part, '2
) When either or both of the bridge collecting plate and the holding plate are ring-shaped, and at least one of them is part of a hollow cylinder in the fiber collection part, {31 The bridge collecting plate and the holding plate are band-shaped. The fiber collecting section is installed on a drum or roll, and at least one side of the fiber collecting section is a part of a hollow cylinder.

Next, as a preferable example of the collecting board and the holding board, 5 to 100
A woven mesh metal or synthetic resin mesh or a perforated plate corresponding to the above-mentioned mesh, supported by rolls or hollow cylindrical drums, in which the hollow cylindrical drums in the fiber collecting section are One example is one that has a through hole with a diameter of 1 to 5 capes on the side.

The thermoplastic resin is made into paper thread from the spinning hole, and is stretched by the action of high-speed gas to become fine fibers, which together with the gas form a fiber stream that is blown onto the collection plate as described above. According to the method, the fiber stream is sprayed onto a collecting plate after the fibers have been sufficiently drawn and come into contact with fine droplets at a portion where they are not completely solidified.

The liquid constituting the droplets is usually water or an aqueous solution or suspension, but depending on the purpose, it may also be an organic solvent or solution such as alcohol, hydrocarbon, or chlorinated hydrocarbon. Aqueous solutions include inorganic salts, surfactants, water-repellent resins,
An aqueous solution of a dye or a mixture with an organic solvent can be used as a suspension, or a suspension with an inorganic substance such as silica, silica gel, calcium carbonate, alumina, alumina gel, talc, clay pigment, disaster prevention agent, etc. Examples include suspensions or emulsions of water-soluble resins, surfactants, and organic substances such as oils, fats, natural oils, fragrances, disaster prevention agents, synthetic resins, and natural resins. The gas used in the present invention is usually air, but depending on the type of thermoplastic resin used, it is also possible to use gases that are inert to the thermoplastic resin, such as nitrogen or carbon dioxide.

It is desirable, but not essential, that the droplets be fine.

Usually its diameter is 0.1 to 1,000 Buddha, preferably 0.
．． 1 to 20, and can be obtained by methods such as spraying, rotary atomization, and ultrasonic atomization, with ultrasonic atomization being particularly suitable for obtaining fine droplets. The method of contacting the droplets with the fiber stream is then achieved by feeding or spraying the liquid bottle obtained in the above method in the vicinity of the collecting plate or directly onto the fiber stream.

The amount of droplets sprayed also depends on various conditions, but when producing nonwoven fabrics of polypropylene, polyamide, polyurethane, etc., the amount of droplets sprayed is 0.1 to 10 parts by weight per 1 part by weight of resin. It is preferable to use The fiber stream and the fibers contained in the fiber stream are thus brought into contact with the droplets, some by the liquid bottle,
In part, not only does the temperature drop rapidly due to the latent heat of vaporization of the droplets, but also liquid molecules adhere to the fiber surface and cover the fiber, cooling the bead-like material and preventing the formation of pinholes. . Further, even if the resin has a slow curing speed, such as nylon 12, the fibers are prevented from fusing together, so a nonwoven fabric made of fine fibers of such a resin can be obtained. Furthermore, the method of the present invention has the advantage that by using droplets of an aqueous solution or suspension, a surface-treated nonwoven fabric can be obtained directly.

Furthermore, in the method of the present invention, the part where the fiber flow contacts the droplet can be arbitrarily set, which not only makes it possible to arbitrarily set the thermal history of the Hina-kama Junction according to the properties of the intended nonwoven fabric. ``Since it does not affect the air flow near the spinning hole, it has the advantage that a stable fiber flow can be obtained continuously for a long time.In the present invention, the place where the fiber flow and the droplets come into contact is The fibers made of the molten resin are sufficiently drawn and completely solidified, and there are no spots, which can be arbitrarily set depending on the paper yarn conditions, the type of resin, etc.

Generally, when the two are brought into contact near the exit of the spinneret,
That location is undesirable because the fibers are quenched, resulting in insufficient stretching of the fibers. Regarding the method of contact between the fiber stream and droplets, there is not only a method of spraying droplets onto the fiber stream, but also a method in which an atmosphere is created in which droplets exist between the die and the bottle collection board, and the fiber stream is sprayed there. It is also possible to use the fiber flow to attract the droplets and bring them into contact. In this way, the method of the present invention discharges water from a water discharge hole installed adjacent to a conventionally known gas discharge hole, and causes water droplets to be included in the high-speed gas from the gas discharge hole. The effect is fundamentally different from that of the method of removing the resin deposited near the paper thread holes (Jikoko No. 20248/1983). In other words, in this method, the purpose of this method is to remove the resin that has settled in the spinning hole or prevent its deposition by spraying water around the spinning hole, and the structure around the paper yarn hole becomes complicated. Not only is it expensive to manufacture, but the adjustment of the splicing holes, gas discharge holes, and water discharge holes is extremely complicated.Furthermore, as these are constantly in contact with water, they are subject to severe corrosion, and special equipment is required to prevent this. There are many technical and economic difficulties, such as the need for different materials. Furthermore, since the fibers spun from the spinning holes are immediately quenched, the fibers cannot be drawn sufficiently, making it difficult to produce non-spun fabrics made of fine fibers. However, according to the method of the present invention, it is possible to sufficiently draw the fibers and then cool them as described above, so that a nonwoven fabric made of fine fibers can be obtained with a simple device. Although FIGS. 1 to 6 show specific examples of the method of the present invention, the present invention is not necessarily limited to these specific examples.

In FIG. 1, the thermoplastic resin is supplied to a hopper 11 of an extruder 1, heated and melted by the extruder 1, and fed to a die 2 installed in the extruder 1, where it is fed into a paper thread hole 21 of the die 2. The yarn is graded continuously. A gas discharge hole 22 and a gas supply pipe 23 for supplying gas to the gas discharge hole 22 are installed in the die 2 adjacent to both sides of the yarn hole 21 . The high pressure gas supplied to the gas supply joint stock 23 of the die 2 is discharged from the gas discharge hole 22 at a speed close to the speed of sound. The thermoplastic resin threaded from the paper thread hole 21 is turned into fine fibers by the high-speed airflow discharged from the gas discharge hole 22, and the fiber flow 7 is formed together with the gas.
form. The fiber stream 7 is sprayed onto the fiber spraying part P of the collector plate 3 after coming into contact with the droplets 101 that are combined from the droplet supply device 10 produced by the droplet production device (for example, ultrasonic spray) of the present invention. It will be done. The collection plate 3 is a mesh or perforated plate made of metal or synthetic resin, and the mesh size is 5 to 200 mesh, preferably 5 to 100 mesh, and more preferably 10 to 40 mesh, and has a hollow cylindrical shape. It is installed on the surface of the drum 31. The drum 31 has a hollow cylindrical shape, and a large number of through holes are installed on its side. The shape of the through hole installed on the side surface is preferably tapered as shown in FIGS. 2 and 3. The fibers blown onto the surface of the collecting plate 3 as the fiber stream 7 are separated from the fiber stream 7 to form the nonwoven fabric 5, which is pressurized to a predetermined thickness by the presser plate 4 and then passed through rolls 71, 71'. It is wound up by a winding machine 8. The holding plate 4 is a net or perforated plate similar to the bottle collecting plate 3, and is wound around a drum 41 and a drum 41' similar to the drum 31. In addition, in the case of Fig. 1, the fiber stream 7 is blown onto the fiber collecting section 6 consisting of the bridge collecting board 3 and the holding plate 4, so when it is sprayed onto a flat collecting slope as shown in Fig. 4a, In comparison, a uniform nonwoven fabric with less scattering of fibers can be obtained. In the present invention, after the fiber stream 7 comes into contact with fine droplets 101, it is sprayed onto a collecting slope to separate the fibers.As shown in FIG. is the fiber flow 7 along with the gas.
This is achieved by spraying it towards the The droplets 101 are dispersed in gas (usually air) and then combined, and the liquid constituting the droplets is usually water, but may be a solution, dispersion, or suspension as described above. . When water droplets are used as the liquid droplets, the amount of water droplets used is usually preferably 0.1 to 1 part by weight per 1 part by weight of the thermoplastic resin. In the case of FIG. 1, the droplet supply device 10 uses ultrasonic spray, but it may also be a simple spray, a rotary atomizer,
An ultrasonic humidifier or the like may also be used. Further, 9 is a spray for cooling the collecting plate 3, but it is not necessary depending on the amount of droplets used. FIG. 4a shows the location where the fiber stream 7 is blown onto a point P on the plane of the annular collecting plate 3 held by the drums 31 and 31'.

In this case, water droplets dispersed by ultrasonic waves by a droplet production device (not shown) are distributed to liquid bottle supply devices 10 and 10' having slit-like entrances 102 and 102' on both sides of the fiber stream 7.
is supplied through the supply pipe 104. Droplet supply device 10
, 10' are supplied to both sides of the fiber stream 7 from the closed parts 102, 102' (Fig. 4b).
is a top view of the droplet supply device 10, 10'.
-W' plane cross-sectional view). FIG. 5a shows an example in which a two-layer nonwoven fabric is produced, in which a nonwoven fabric made of thick fibers is produced from the extruder 1, and then fine fibers are sprayed from the extruder 1'. In this case, the fiber stream 7' from the extruder 1' is sprayed onto the bottle collecting plate through the gap 201 of the slit 200, and at the same time, droplets are sprayed from between the slit 200 and the die 2'. In this way, the fiber stream 7' is sprayed through the slit 200 onto the first nonwoven fabric 5 formed on the bridge collecting board 3, and at the same time, the slit 200
It is desirable to supply the droplets from between 00 and the die 2', since the supplied droplets very easily come into contact with the fiber stream 7' and the fibers. As shown in FIG. 5b, the distance 1 between the slit 200 and the die 2' is usually 15 to 50 ribs, preferably 50 to 20 ribs, and the gap 2 between the slit 200
The middle f of 01 is usually 20-20, preferably 50-1
00 sail, and the length g of the slit must be wider than that in the fiber stream, and is usually 20 to 200 mm wider than that in the fiber stream.
It is desirable that it be larger by 50 to 100 ribs, preferably 50 to 100 ribs. Although the size of the slit 200 is not particularly limited, if it is too small, the effect of the slit 200 cannot be obtained sufficiently. In order to fully obtain the effect of the slit 200, the medium h should be at least twice the length of f, preferably 3 to 5 times, and the length i should be -1g is at least twice the length of f, preferably 3 to 5 times. It is desirable to double the amount. Next, FIG. 6 shows a hollow cylindrical drum 31 and 41 with two perforated plates on their sides, and a camphor tree collecting plate 3 and a holding plate 4 installed therein. Intersections A, A between 42 and the bottle collection board 3 and presser board 4
’ is sprayed between.

After the fibers are separated from the fiber stream blown between A and A', they are pressurized to a constant thickness by a collecting plate 3 and a holding plate 4. In this case, the liquid bottle is supplied from droplet supply devices 10 and 10' installed on both sides of the fiber stream 7, and the entire device is housed in a container 400. Further, such an apparatus is suitable for cases where liquid droplets other than water, such as an aqueous solution, suspension, or dispersion, are used. Furthermore, the nonwoven fabric obtained in this case is a nonwoven fabric in which the fibers 51 are perpendicular to the surface 30 as shown in Figures 7a and b, and by dividing it into two pieces, as shown in Figure 7c. A brushed nonwoven fabric is obtained. In addition, in this case, a woven or non-woven fabric is wrapped around the collector plate 3 and the presser plate 4,
A laminated nonwoven fabric can also be obtained by blowing a fiber stream onto the surface. Hereinafter, the method of the present invention will be explained in detail with reference to Examples. Example 1 Using polypropylene with a melt flow rate of 15.0, as shown in Figure 1, a diameter of 10 mm made only of water was 80 mm
Two types of nonwoven fabrics A and B having different basis weights were produced by spraying droplets of 1 gram per 1 gram of polypropylene from the spray nozzle 10 and bringing them into contact with the fiber stream.

On the other hand, two types of nonwoven fabrics A' and B were similarly produced using a conventional method that does not involve spraying droplets.

The properties of these nonwoven fabrics are shown in Table 1, and polypropylene nonwoven fabrics A and B obtained by the method of the present invention
All of them have no pinholes, have a good texture, and are excellent in other properties, and it can be seen that nonwoven fabric A is suitable for use as a separator for alkaline batteries, and nonwoven fabric B is suitable for use as a mask filter. Table 1 Example 2 A polypropylene nonwoven fabric was produced in the same manner as in Example 1.

However, instead of the water droplets in Example 1, the weight percent of silica sol 1
, surfactant (Toho Chemical Co., Ltd. product Emalgen) 1% by weight
and the remainder water. On the other hand, a nonwoven fabric was produced in the same manner except that droplets of the above mixture were not used.

The pinhole density and physical properties of the nonwoven fabrics obtained by these methods are shown in Table 2. The nonwoven fabrics obtained by the method of the present invention have no pinholes and have good stiffness even though they do not come into contact with droplets. It can be seen that the results are much improved compared to what was obtained. Table 2 Example 3 Nylon 12 instead of polypropylene {General formula H-
NH-(C ratio),. Example 1 using CO]nOH}
A nonwoven fabric made of nylon 12 was manufactured using the same machine.

The results are shown in Table 3, and as is clear from Table 3, in the case of the method that does not contact with droplets, the fibrous resin extruded from the die fuses with each other and forms a fibrous layer. However, in the case of the method of the present invention, which involves contact with a liquid bottle, a nonwoven fabric made of nylon 12 can be produced with good workability, and the nonwoven fabric has excellent properties. I understand. Table 3 Example 4 In the same manner as in Example 1, using a thermoplastic polyurethane elastomer consisting of polytetramethylene ether glycol and 4,4'-diphenylmethane diisocyanate instead of polypropylene. A nonwoven fabric made of thermoplastic polyurethane was produced.

However, instead of the droplets made only of water in Example 1, 95% of water was used.
The results are shown in Table 4 using a liquid bottle containing a mixture of 5% by weight of process oil and 5% by weight of process oil. When not in contact with liquid droplets, it was not possible to form a fibrous layer; however, in the case of contact with droplets, a nonwoven fabric made of thermoplastic polyurethane tongue could be manufactured with good workability, and the nonwoven fabric had excellent properties. It can be seen that it has

Table 4 Example 5 A nonwoven fabric made of pitch was produced in the same manner as in Example 1 using pitch with a melting point of 250q0.

Note that it was not possible to produce a nonwoven fabric when it was not brought into contact with droplets. The pitch nonwoven fabric thus obtained is useful as a raw material for carbon fibers.

[Brief explanation of the drawing]

Fig. 1 is a detailed view of the method of the present invention, Fig. 2 is Fig. 1,
Drum 31 in Figures 5a and 6 and drum 41 in Figure 6
FIG. 3 is a cross-sectional view of FIG. 2, FIG. W-W' line cross-sectional view, No. 5
Figure a is an embodiment of the method of the present invention, and figure b is a slit 20.
0, FIG. 6 shows an embodiment of the method of the present invention, and FIG. 7 shows a cross-sectional structural diagram of a nonwoven fabric produced by the method of the present invention (particularly the method shown in FIG. 6). O diagram O2 diagram O3 diagram Om diagram O5 diagram 6 figure 7 spear figure

Claims (1)

[Scope of Claims] 1. Continuously spinning a molten thermoplastic resin through a plurality of spinning holes installed in a spinning device, and at the same time discharging gas at high speed from a gas discharge hole installed adjacent to the spinning holes. In a method for producing a nonwoven cloth made of the fibers by drawing the thermoplastic resin fibers and forming a fiber stream consisting of the fibers and the gas, and then spraying the fiber stream onto a collection plate. . A method for producing a nonwoven fabric, characterized in that the fiber stream is brought into contact with fine droplets at a portion where the fibers are sufficiently drawn and not completely solidified, and then sprayed onto a collection plate and collected. 2. The method according to claim 1, wherein the droplets are water droplets. 3. The method according to claim 1 or 2, wherein the water droplets are water droplets consisting of water, an aqueous solution, or a suspension. 4. The method according to claim 1, 2 or 3, wherein the droplets have a diameter of 0.1 to 100μ. 5. The method according to claim 1, 2, 3 or 4, wherein the thermoplastic resin is polyamide, thermoplastic polyurethane, polyolefin, polyester or pitch.