JPH0765264B2 - Melt blow spinning method and melt blow spinning apparatus - Google Patents

Description

TECHNICAL FIELD The present invention relates to a melt blow spinning method and a melt blow spinning apparatus which are effective for providing a melt blow nonwoven fabric having a uniform basis weight distribution in the width direction, and particularly to a sheet. The present invention relates to a melt-blowing spinning method and a melt-blowing spinning device which are effective for making the areal weight distribution and the physical properties uniform at the widthwise end of the.

[Prior Art] Conventionally, as a melt blowing apparatus and method effective for producing a melt blue non-woven fabric having a uniform basis weight distribution by controlling an air flow, Japanese Patent Publication No. Sho 62-12345 and Japanese Unexamined Patent Publication No. The technology described in Japanese Patent No. 134176 is proposed.

Among them, in the invention described in Japanese Examined Patent Publication No. 62-12345, the uniformization of the non-woven fabric sheet is performed by fixing the side plate for rectification and the exhaust duct, etc. between the time when the polymer is discharged from the die and the time when the polymer is collected. This is achieved by using a tool.

Further, in the invention described in JP-A-54-134176, the sheet is made uniform by devising the suction method of the exhaust duct.

As can be seen from these conventional techniques, in the conventional art, after the polymer is exclusively discharged from the die, the injection gas port width is optimized, and the associated air is controlled to make the non-woven fabric uniform, particularly the end portion of the non-woven fabric sheet. No means for achieving uniformity in the above has been considered.

[Problems to be Solved by the Invention] In view of the above points, an object of the present invention is to provide a melt-blown nonwoven fabric having a uniform distribution in the fabric weight in the width direction, and particularly a uniform distribution in the fabric weight at the edges in the sheet width direction and the physical properties. It is intended to provide a method and device for doing so.

[Means for Solving the Problem] In order to solve the above problems, the present invention has the following configuration.

That is, in the melt blown spinning method of the present invention, a melt blown non-woven fabric is produced by injecting a gas into a fiber by injecting a gas from an injection gas port provided adjacent to a plurality of molten polymer discharge holes arranged therein, and then collecting the fiber. In the melt-blowing spinning method, the width of the injection gas in the width direction of the nonwoven fabric is made wider than the width of the discharge hole array of the molten polymer by 2 cm or more on one side.

Further, in the present invention, the method is preferably characterized in that the injection gas port width is made wider than the width of the discharge port hole of the molten polymer by at least 5 cm.

Further, the melt-blowing spinning device of the present invention produces a fiber by jetting gas from a jetting gas port provided adjacent to a plurality of molten polymer discharge holes, and then collecting the fiber to produce a melt-blown nonwoven fabric. The melt blow spinning device is characterized in that the width of the injection gas in the width direction of the nonwoven fabric is made wider than the width of the discharge hole array of the molten polymer by 2 cm or more on one side.

[Operation] Hereinafter, the present invention will be described in detail.

Generally, as a means for making the sheet unevenness in the width direction of the meltblown nonwoven fabric as uniform as possible, it is important to make the assembly of the injection gas ports uniform, but no matter how evenly assembled, the end portion of the sheet width direction is There is a problem in that the basis weight distribution is not uniform due to the influence of the accompanying air from the width direction and the basis weight of the end portions increases.

The product sheet width is generally narrower than the mouthpiece width, although it depends on the collection distance. Therefore, there arise problems of effective sheet width, reduction of product yield, and change of physical properties.

For this reason, methods such as a combination of the rectifying side plate and the exhaust duct and a suction method for the exhaust duct have been proposed, but it is surprisingly difficult to set the conditions for these methods.

Further, the installation of the rectifying side plate or the like brings about a disadvantage that the workability of observing the die discharge portion and the cloth making is deteriorated.

For this reason, the present inventors have an effect of making the widthwise end portions of the sheet uniform by another method, and
As a result of extensive studies on the relationship between the injection gas port width that injects gas and the width of the molten polymer discharge hole array, etc., as a result of obtaining melt-blowing spinning technology that can bring many effects to uniformization over the entire width, the collection distance , The required width varies depending on the amount of injected gas and the pressure of the injected gas, but by constructing the equipment so that at least the width of the injected gas is wider than the width of the discharge hole row of the molten polymer, the basis weight distribution at the end in the sheet width direction is It has been found that the uniformity is improved without being affected by.

That is, the method of the present invention is effective sheet width, product yield,
This is a method capable of producing a melt-blown non-woven fabric that improves the physical properties of a sheet, and the equipment is configured so that the injection gas port width is wider than the width of the molten polymer discharge hole array.

In the widely installed part, the contribution of polymer to fiber is small,
Although it may seem inefficient in some cases, the injected gas in the same part acts as a barrier against so-called entrained air that flows in from the outside, and only improves the basis weight distribution in the sheet width direction edge part. Not only that, with the accompanying air, the difference in fineness due to the difference in fiber cooling speed between the central portion and the end portion of the sheet is reduced, the difference in physical properties is reduced, and the effective sheet width and the product yield are improved.

Regarding the injection gas port width, it can be said that it is effective if the width that can be set wider than the width of the discharge hole row of the molten polymer is wide, but if the collection distance is about 10 to 50 cm, the widening distance is at least one side. 20 cm or more is recommended.

It is preferably 5 cm or more, more preferably 10 cm or more.

If the width of the injection gas opening, which is wider than the width of the discharge hole array of the molten polymer, is less than 2 cm on one side, the effect is small.

In order to explain the melt blow spinning method according to the present invention,
This will be described in more detail with reference to the model diagrams of the melt blowing apparatus shown in FIGS. 1, 2 and 3.

FIG. 1 is a schematic view of a melt-blowing device, FIG. 2 is an enlarged cross-sectional schematic view of a mouthpiece portion, and FIG. 3 is a schematic view of the vicinity of the mouthpiece portion when the vicinity of the mouthpiece discharge surface is seen from the polymer discharge direction.

In FIG. 1, gas lines 2 and 2'for supplying a jet gas are provided from both left and right sides of the drawing of the spin block 1 in which a spinneret is set, and air control valves 3 and 3'are respectively installed in the gas lines. The supply amount is variable. Also,
The gas heating heat exchangers 4 and 4'are arranged at the rear side to heat the gas. The molten polymer is supplied to the spin block 1 from the extruder 5 via the gear pump 6 and the filter 7.

FIG. 2 is an enlarged view of the vicinity of the nozzle, in which the mouthpiece 8 and the gas guiders 9 and 9'are combined to form the gas injection holes 10 and 10 'on both sides. The nozzle tip of the mouthpiece part 8 projects from the gas injection ports 10 and 10 ', and the gas lines 2 and 2'supplying the injection gas shown in FIG. 1 are connected to the gas injection ports 10 and 10'. ing.

In FIG. 3, the die 8 is provided with a plurality of discharge holes 11 in a row, and the polymer is melt-spun from the discharge holes 11. In the present invention, as shown in FIG. 3, the width between the discharge holes located at both ends is defined as the "width of the melted polymer discharge hole array".

The space between the base 8 and the gas guider 9, that is, the gas injection port 10 is partitioned by side plates 12 and 12 '. In the present invention, the width between the side plates 12 and 12 ', that is, the width between both ends of the gas injection port is referred to as "injection gas port width", and this injection gas port width is the width of the molten polymer discharge hole array. As described above, at least one of them is wider than 2 cm.

By adopting such a melt blow spinning device and melt blow spinning method, the gas flow injected from a widely installed portion acts as a barrier against so-called associated air flow flowing from the outside during melt blowing. The basis weight distribution of the sheet width direction end portion of the obtained nonwoven fabric can be made very good.

Further, the difference in fineness due to the difference in the fiber cooling speed between the central portion and the end portion of the sheet caused by the entrained air flow is reduced, and the uniformity of the sheet characteristics is improved.

As a result, the effective sheet width and the product yield are improved.

[Examples] The present invention will be described below with reference to Examples.

The method for measuring the sheet areal weight distribution is as follows.

The sheet is taken out from the end mouth hole to a position directly under 30 cm inside, and strip-shaped samples are taken at intervals of 2 cm in the width direction and 20 cm in the length direction.

Calculate the weight of the strips and compare the distribution of the areal weights. As shown in the abscissa of the diagram in Fig. 4, the distribution of the areal weights is based on the base position (0 cm) at the end of the die and the inner side of the non-woven fabric side is 32 cm in 2 cm increments above. It was measured by measuring the basis weight up to 4 cm in increments of 2 cm on the outer end side of the reference position.

The fineness is measured by taking a 1000 times photograph of the surface of the fabric sheet with an electron microscope and determining the peak fineness from the frequency distribution of 300 lines.

Example In assembling a melt blow mouthpiece having a width of a discharge hole array of molten polymer of 1.2 m, the injection gas port width was 1.4 m, and both ends were
The average value of the difference between the gas injection port and the nozzle tip (nozzle protrusion length) is 1.4 m for those with a wide gas injection port of 10 cm each.
m, variation R = 0.09 mm, average value of gas injection port (gap width) 0.7 mm, variation R = 0.1 mm.

This device supplies heated air of 0.9 Nm ³ / min per 10 cm,
The results of melt blown spinning at a polypropylene collection distance of 30 cm are shown in Table 1 and FIG.

Comparative Example In assembling a melt blow mouthpiece with a 1.2 m wide row of discharge holes for molten polymer, the injection gas mouth width was 1.21 m, and as shown in FIG. 2 of Japanese Utility Model Laid-Open No. 1-62391, the melt spinning was performed from the mouthpiece. If the difference between the effective width of the molten polymer (width of the die hole row) and the width of the gas injection port (0.5 cm on one side) is the same,
Others were the same as those in the above-mentioned embodiment and were assembled with the same assembly precision.

This device supplies heated air of 0.9 Nm ³ / min per 10 cm,
The results of melt blown spinning of polypropylene at a collection distance of 30 cm are shown in Table 1 and FIG.

As can be seen from these results, when comparing the example according to the present invention and the example according to the comparative example, according to the method and the apparatus according to the present invention, the basis weight distribution of the sheet width direction end portion becomes good, which is caused by the accompanying air. It is possible to obtain a non-woven fabric sheet having a small difference in fineness due to a difference in fiber cooling speed between the central portion and the end portion of the sheet, a wide effective sheet width, and an improvement in product yield.

On the other hand, in the comparative example, the fabric weight distribution at the end portion in the sheet width direction is large, the fineness at the same portion is also thick, and only the nonwoven fabric having a narrow sheet width can be obtained. Met.

[Advantages of the Invention] The melt-blown nonwoven fabric obtained in the present invention not only has a uniform basis weight distribution in the sheet width direction end portion, but also has a difference in fineness due to a difference in fiber cooling speed between the central portion and the end portion of the sheet due to the accompanying air. It is an excellent product that has been reduced.

Further, according to the present invention, the effect of improving the effective sheet width and the product yield can be brought about.

The meltblown nonwoven fabric obtained by the present invention is a useful meltblown spinning method and meltblown spinning apparatus capable of providing a wide range of substrates such as various filters, wipers, masks, dustproof garments, and separators.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall outline of a melt blow spinning device. FIG. 2 is an enlarged cross-sectional schematic view of the mouthpiece portion of the meltblowing device. FIG. 3 is a diagram showing an example of a nozzle configuration according to the melt blowing device of the present invention, and is a schematic view of a nozzle portion when the vicinity of the discharge surface of the die is viewed from the discharge direction side. FIG. 4 shows the measurement results of the sheet distributions obtained in the examples and the comparative examples. The weights of the strip-shaped samples were determined to examine the distributions, and the results according to the present invention and those according to the comparative examples are shown in comparison. It is a graph. 1: Spin block 2, 2 ': Gas line 3, 3': Gas control valve 4, 4 ': Heat exchanger 5: Extruder 6: Gear pump 7: Filter 8: Cap 9,9': Gas guider 10, 10 ': Gas Jet 11: Mouth hole 12, 12 ': Side plate

Continuation of the front page (56) Reference JP-A-58-41960 (JP, A) JP-A-2-26976 (JP, A) JP-A 52-59775 (JP, A) JP-B-49-30861 (JP , B1)

Claims (3)

[Claims] 1. A melt blown spinning method for producing a melt blown nonwoven fabric by injecting a gas from an injection gas port provided adjacent to a plurality of molten polymer discharge holes to form a fiber, and then collecting the fiber to produce a melt blown nonwoven fabric. A melt blow spinning method, characterized in that the width of the injection gas port in the width direction of the nonwoven fabric is made wider than the width of the discharge hole array of the molten polymer by at least 2 cm. 2. The melt blown spinning method according to claim 1, wherein the injection gas port width is made wider than the width of the molten polymer discharge hole array by 5 cm or more on one side. 3. A melt-blowing spinning apparatus for producing a melt-blown nonwoven fabric by injecting a gas from an injection gas port provided adjacent to a plurality of molten polymer discharge holes to form a fiber, and then collecting the fiber to produce a melt-blown nonwoven fabric, A melt blow spinning device characterized in that the width of the injection gas port in the width direction of the non-woven fabric is made wider than the width of the discharge hole array of the molten polymer by at least 2 cm.