JP3223390B2 - Melt blow device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

[0001] The present invention relates to a melt blow apparatus. More specifically, the present invention relates to a melt blow apparatus capable of producing a melt blown nonwoven fabric having no variation in the flow velocity distribution of the heating gas, uniform fiber diameter distribution and uniform fiber distribution, and non-uniform weight and thickness.

[0002]

2. Description of the Related Art In a melt-blowing apparatus, a slit-shaped gap to be a supply path of a heating gas, that is, an air slot is formed between a nozzle piece and an air lip plate, and the heating gas is spun through the air slot. The molten resin is injected near the mouth, and the molten resin spun from the spinning mouth is drawn and thinned by the ejection force. Therefore, if there is a variation in the flow velocity distribution of the heating gas, the fiber diameter distribution and the fiber distribution of the melt-blown non-woven fabric produced by the apparatus also vary, and the produced melt-blown non-woven fabric has uneven weight and uneven thickness. Was invited.

[0003] In the conventional melt blower, by adjusting the gap between the air slots, variation in the flow velocity distribution of the heating gas is prevented.

[0004]

However, in the conventional melt blower, as shown in FIG. 7, the air lip plate 4 is fixed laterally to the nozzle piece 3 with bolts 5, so that the center portion is formed. Since the gap between the formed air slots 2 is maintained, the gap between the air slots 2 easily changes due to the temperature difference between the time of cooling and the time of heating (300 to 350 ° C.). Even if it was adjusted, the flow velocity distribution as adjusted could not be obtained during spinning.

In addition, since the gap between the air slots is adjusted to a predetermined interval by an operator by inserting a gauge plate into the gap between the nozzle piece and the air lip plate, an artificial variation appears, and high accuracy is required. Could not be adjusted. For example, when trying to adjust the gap between the air slots at intervals of 0.3 mm, an error of about 10 to 20 μm has occurred.

The present invention has been made in view of the above circumstances, and provides a melt-blown nonwoven fabric having no variation in the flow velocity distribution of the heating gas, having a uniform fiber diameter distribution and a uniform fiber distribution, and having no uneven weight and thickness. It is an object of the present invention to provide a melt-blowing apparatus capable of performing the above-described steps.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a nozzle peak is provided.
Formed when the air lip plate and the air lip plate are joined.
With a blocking wall that blocks a part of the heating gas supply path
In addition, the sum total of the air slots
Orifice-like passage with an opening area smaller than the product
The gist of the present invention is a melt blow device characterized by being provided .

[0008] According to the second aspect of the present invention, an air refill is provided.
Lip plate and the side of the air lip plate and heated gas
It is fixed at two places on the blocking wall that blocks a part of the supply channel.
The gist of the present invention is a melt blow apparatus according to claim 1 .

According to a third aspect of the present invention, the total of the opening areas of the orifice-shaped passages is 60 to 90% of the cross-sectional area of the air slot. Was the gist.

[0010] In the invention according to claim 4, the blocking wall is provided.
3. The device according to claim 1, wherein the device is exchangeable.
The melt-blowing apparatus of the above was the gist.

Hereinafter, a melt blow apparatus according to the present invention will be described in detail with reference to the drawings. The melt blow device 11 shown in FIG. 1 includes a die body 12, a nozzle piece 13 attached to the die body 12 with bolts, and an air lip plate 14. It should be noted that the melt blow apparatus 11 shown in the drawings is merely an illustrative example, and each configuration can be appropriately changed within the scope described in the claims.

A resin inlet 15 for receiving molten resin is provided at an upper portion of the die body 12.
Inside 2, a flow path 16 formed into a slit shape for distributing the molten resin supplied from the resin inlet 15 in the width direction of the die body 12, and for guiding the molten resin from the resin inlet 15 to the flow path 16. Are provided. Further, an extruder (not shown) for sending out the molten resin and a heater (not shown) for melting the resin are provided above the die body 12, so that the resin can be melted and extruded. I have. At the left and right ends of the die body 12,
A gas supply port 18 for taking in a heated gas is arranged, and a gas supply pipe 19 is arranged inside. still,
As the gas supply pipe 19, a device for obtaining a uniform air flow may be employed.

The nozzle piece 13 has a substantially isosceles triangular cross section, and a flow path 21 of molten resin is formed inside the nozzle piece 13 in the width direction of the nozzle piece 13. In this flow path 21, the molten resin from each of the resin inlets 15 is filled with the flow path 1.
7. The nozzle orifice 2 is provided in the nozzle piece 13 and is guided through a flow path 16.
The feed is supplied to the spinning port 24 at the tip of the nozzle piece 13 via the nozzle 3.

The air lip plate 14 is a plate which is attached to the lower part of the die body 12 in a state where the air lip plate 14 is joined to the nozzle piece 13. 14, a slit-shaped gap to be a heating gas supply path, that is, an air slot 20.
Is formed. The heating gas from the gas supply pipe 19 is injected near the spinning port 24 through the air slot 20, and the molten resin is drawn and narrowed by the injection force.

In a part of the heating gas supply path from the gas supply pipe 19 of the die body 12 to the air slot 20 formed between the nozzle piece 13 and the air lip plate 14 in the melt blow apparatus 11, the sum total is equal to the air slot. An orifice-shaped passage having an opening area smaller than the cross-sectional area is provided.

That is, as shown in FIG. 2 and FIG.
-When the lip plate 14 is joined to the nozzle piece 13
A part of the heating gas supply passage 27 formed at the time of
The total of the opening area penetrates the cut wall 26 and the air slot is
An orifice-like passage 25 smaller than the cross-sectional area of 20 is provided.
It has been damaged.

For this reason, the processing in the melt blower is
Shape of the part with the highest ventilation resistance in the hot gas supply path
Is fixed and the opening area does not change.
Fruit, Do variation occurs in the flow velocity distribution of the substantive heated gas
It has become.

The passage 25 may be provided in any one of the die body 12, the nozzle piece 13, and the air lip plate 14, and the number thereof is not limited. The opening area of the passage may have a total sum smaller than the cross-sectional area of the air slot.
When it is 0%, the flow velocity distribution of the heating gas is stable, and a uniform nonwoven fabric having no variation in fiber diameter distribution or fiber distribution can be manufactured.

FIGS. 2 and 3 show that when the air lip plate 14 is joined to the nozzle piece 13, the air lip plate 14 is provided with a blocking wall 26 that blocks a part of the heating gas supply path 27. A large number of orifice-like passages 25 whose total opening area is smaller than the cross-sectional area of the air slot 20 are provided in the wall 26 across the width of the blocking wall 26. As a result, the passage 25 provided through the blocking wall 26 is the portion having the largest ventilation resistance in the heating gas supply passage 27 in the melt blow device 11, but the shape and the opening area of the passage 25 do not change. The flow rate of the heating gas supplied to the air slot 20 through the passage 25 is made uniform among the passage groups provided in the width direction of the blocking wall 26. At the same time, the flow rate of the heating gas in each passage 25 does not change with time.

FIGS. 2 and 3 show a heating gas formed when the air lip plate 14 is joined to the side of the air lip plate 14 and the nozzle piece 13 and the air lip plate 14. It is fixed to the die 12 and the nozzle piece 13 by bolts 28 and 29 at two places on a blocking wall 26 that blocks the supply path 27, and has a stable structure in which the gap of the air slot 20 does not easily change.

FIGS. 4 and 5 show another example of the heating gas supply path, in which the blocking wall 26 is formed of a member independent of the air lip plate 14, and is adapted to the spinning conditions. The opening area of the orifice-like passage can be changed by replacing the blocking wall. The blocking wall 26 is fixed to the air lip plate 14 by bolts 30, and the air lip plate 14 is fixed to the die 12 by bolts 28. At the same time that the air lip plate 14 is fixed to the die 12, the blocking wall 26 is pressed against the die 12 or the nozzle plate 13 and fixed by pressure, so that the air lip plate 14 is substantially fixed at two places. Thus, the air slot 20 has a stable structure that does not easily change. When the blocking wall is crimped and fixed as described above, it is not necessary to penetrate the bolt into the blocking wall, so that the orifice-like passage can be freely designed, and the orifice-like passage can be more uniformly arranged in the width direction.

[0022]

Embodiment 1 When the air lip plate 14 shown in FIGS. 4 and 5 is joined to the nozzle piece 13, a blocking wall 26 for blocking a part of the heating gas supply path 27 is provided on the air lip plate 14. Using a melt-blowing device in which a large number of orifice-shaped passages 25 whose total opening area is 72% of the cross-sectional area of the air slot 20 is provided in the wall 26 over the width direction of the blocking wall 26, the gap between the air slots 20 is reduced. 0.4m
m, the temperature of the heated gas is 350 ° C., and the pressure is 1.0 kg /
In order to examine the distribution of the flow velocity of the heated gas in the width direction when the pressure was set to cm 2 G, the distribution of the ejection pressure of the heated gas was measured by applying a simple measuring device in which a differential pressure gauge was connected to an injection needle to an air slot. The result is shown in FIG.

Example 2 Using the same melt-blowing apparatus as in Example 1, the gap of the air slot 20 was 0.3 mm, the temperature of the heating gas was 300 ° C., and the pressure of the heating gas was 1.0 kg / cm 2 G. The distribution of the ejection pressure in the width direction was measured by a simple measuring device using an injection needle. The result is shown in FIG.

COMPARATIVE EXAMPLE 1 An air lip plate 4 shown in FIG. 7 is fixed laterally to a nozzle piece 3 with bolts 5 so as to maintain a gap of an air slot 2 formed in a central portion. Use air slot clearance of 0.4
mm, heated gas temperature 350 ° C, pressure 1.0kg
The distribution of the ejection pressure in the width direction of the heated gas at / cm 2 G was measured by a simple measuring instrument using an injection needle. The result is shown in FIG.

COMPARATIVE EXAMPLE 2 Using the same melt-blowing apparatus as in Comparative Example 1, the gap of the air slot 2 was 0.3 mm, the temperature of the heating gas was 300 ° C., and the pressure of the heating gas was 1.0 kg / cm 2 G. The distribution of the ejection pressure in the width direction was measured by a simple measuring device using an injection needle. The result is shown in FIG.

Comparative Example 3 Using the same melt blow apparatus as in Comparative Example 1, the gap of the air slot 2 was 0.3 mm, the temperature of the heating gas was 40 ° C.
When the pressure was set to 1.0 kg / cm 2 G, the distribution of the ejection pressure in the width direction of the heated gas was measured by a simple measuring device using an injection needle. The result is shown in FIG.

As is apparent from FIG. 6, the flow rate distributions of Comparative Example 1 and Comparative Example 2 are different between Example 1, Comparative Example 1, Example 2 and Comparative Example 2 in which the gap, temperature and pressure of the air slots are the same. Have variations of ± 9% and ± 6%, respectively, whereas in Examples 1 and 2, there was hardly any variation in the flow velocity distribution. Also, in Comparative Example 3 and Comparative Examples 1 and 2 in which the temperature of the heating gas is different, the variation of Comparative Example 3 in which the temperature is low is small. On the other hand, although the temperatures of Examples 1 and 2 were different between 300 ° C. and 350 ° C., almost no variation was observed in the flow velocity distribution.

Using the melt blow apparatus of Example 1, the polypropylene resin was melt-spun at 290 ° C. at an extrusion rate of 0.25 g / min so that the filament diameter became 1.5 μm. At a temperature of 310 ° C. and a pressure of 1.3 kg / cm 2 G to produce a melt blown nonwoven fabric. The basis weight distribution and the air permeability distribution in the width direction of the obtained nonwoven fabric were measured and are shown in Table 1.

Using the melt-blowing apparatus of Comparative Example 1, the polypropylene resin was melt-spun at 290 ° C. at an extrusion rate of 0.25 g / min so that the filament diameter became 1.5 μm. At a temperature of 310 ° C. and a pressure of 1.0 kg / cm 2 G to produce a melt blown nonwoven fabric. The basis weight distribution and the air permeability distribution in the width direction of the obtained nonwoven fabric were measured and are shown in Table 1.

The basis weight distribution is non-woven fabric (total width: 76 cm)
2cm width from one side end to the other side end
A 15 cm sample was cut out sequentially, the basis weight of each sample was measured, and the distribution was examined. The air permeability distribution was measured by using a Frazier air permeability tester (measurement range: 7 cmφ), measuring the air permeability from the one end of the nonwoven fabric to the other end at a 3.5 cm pitch while shifting the measurement center in the width direction. Was examined.

Table 1

From Table 1, it can be seen that the melt-blown non-woven fabric produced using the melt-blowing apparatus of Example 1 has less variation in both the basis weight distribution and the air permeability distribution than those produced using the melt-blown apparatus of Comparative Example 1. It was confirmed that the melt blown nonwoven fabric was homogeneous.

[0033]

According to the present invention, the above-mentioned structure is provided.
In the melt blower described, the nozzle piece and
Heating formed when joining with the lip plate
In addition to providing a blocking wall that blocks a part of the gas supply path,
The total sum exceeds the cross-sectional area of the air slot
Orifice-shaped passage with a small opening area
From this, the shape of the portion having the largest ventilation resistance in the heating gas supply path in the melt blowing device is fixed,
Since the opening area does not change and the flow velocity distribution of the heating gas does not substantially vary, it is possible to produce a melt-blown nonwoven fabric having a uniform fiber diameter distribution and a uniform fiber weight distribution and a uniform thickness. it can.

According to the second aspect of the present invention, the air lip plate cuts off a side of the air lip plate and a heating gas supply path formed when the nozzle piece and the air lip plate are joined. Since it is fixed to the nozzle piece at two locations on the blocking wall, the gap between the air slots does not change easily, and a nonwoven fabric with stable quality can be manufactured.

According to the third aspect of the present invention, since the total opening area of the passage is 60 to 90% of the cross-sectional area of the air slot, the flow velocity distribution of the heating gas is most stable, and the fiber diameter distribution. And a homogeneous nonwoven fabric having no variation in fiber distribution can be manufactured.

In the melt blow apparatus according to claim 4,
Has a replaceable barrier and can be changed according to the spinning conditions.
Open the orifice-like passage by replacing the barrier
The mouth area can be changed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a state in which a nozzle piece in a melt blow device of the present invention is attached to a die body.

FIG. 2 is an enlarged sectional view showing a heating gas supply path in the melt blowing device of the present invention.

FIG. 3 is an enlarged sectional view showing the blocking wall of FIG. 2 and a large number of orifice-shaped passages provided in the blocking wall.

FIG. 4 is an enlarged cross-sectional view showing another example of the heating gas supply path in the melt blowing device of the present invention.

FIG. 5 is an enlarged sectional view showing the blocking wall of FIG. 4 and a large number of orifice-shaped passages provided in the blocking wall.

FIG. 6 is a graph showing a flow velocity distribution in a width direction of a heating gas.

FIG. 7 is an enlarged sectional view showing a heating gas supply path in a conventional melt blow device.

[Explanation of symbols]

 13 nozzle nozzle 14 air lip plate 20 air slot 25 orifice-like passage 26 blocking wall 27 heating gas supply passage

Continuation of the front page (56) References JP-A-1-62391 (JP, U) JP-B-41-7883 (JP, B1) European Patent Application Publication 377926 (EP, A1) (58) Fields investigated (Int) .Cl. ⁷ , DB name) D01D 5/08 D01D 4/00 D04H 1/72 D04H 3/14-3/16

Claims (4)

(57) [Claims] 1. A nozzle piece and an air lip plate
Cut off part of the heating gas supply path formed when joining
A barrier wall, and a total
Has an opening area smaller than the cross-sectional area of the air slot
Characterized in that an orifice-shaped passage is provided.
Blow device. 2. The air lip plate is the same as the air lip plate.
Of a blocking wall that blocks the side of the rate and part of the heating gas supply path
2. The fixing device according to claim 1, wherein the fixing member is fixed at two places.
Melt blown equipment. 3. The melt-blowing apparatus according to claim 1, wherein the total opening area of the orifice-shaped passage is 60 to 90% of the cross-sectional area of the air slot. 4. The method according to claim 1, wherein the barrier is replaceable.
The melt blow device according to claim 1.