JP3450107B2 - Melt blow spinneret - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a melt-blown nonwoven fabric.
This is related to the spinneret used for manufacturing
Efficient with energy, uniform and ultra-fine with little spots
Melt blow spinneret capable of producing fiber non-woven fabric
Related. [0002] 2. Description of the Related Art A thermoplastic polymer is melted and discharged from a die.
And a pair of so-called lip portions provided adjacent to the base
High-speed hot gas flow from the slit formed between
Fiber formed by jetting and thinning sheet
The melt blow method obtained by collecting on the top is a conventionally known method.
Yes, fibers that constitute the nonwoven fabric obtained by the melt blow method
Is generally as thin as a few microns or less.
Suitable for filters, wipers, batting for clothing, etc.
It has been. [0003] The spinneret used in the melt blow method
For example, JP-A-49-48921 and JP-A-5-49921
It is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-90663. They are
Discharge hole diameter, gas slit width, slit injection angle, nozzle tip
By appropriately adjusting the width of the flat part at the end
Low, continuous operation possible, adjustment and cleaning, discharge port tip
We also provide a melt blow die that does not easily scratch the end
It is. On the other hand, the productivity is improved by the melt blow method.
When increasing the number of holes per row,
The number of holes per row can be increased by increasing the
In this case, the pitch between adjacent holes becomes shorter and
Unfavorable because the polymer streams contact and fuse together
No. To increase the discharge rate per single hole, use melt blow spinning.
There is a limit because the thread cap itself is not high in pressure resistance. JP
No. 5-117954 discloses that the spinneret has improved pressure resistance.
Between the polymer introduction hole and the discharge hole.
A method of providing a plurality of introduction holes having different hole diameters is described.
However, increasing the single hole discharge rate increases the fiber diameter and makes it thinner.
For this reason, a larger hot gas flow or a gas flow
The lit width will be reduced, and energy and process
Not theoretically preferable. Also, Japanese Patent Application Laid-Open No. Hei 3-260154
Has a high-speed gas flow path only around each discharge hole,
Describes a method that can improve the withstand pressure and reduce the gas flow rate
However, in this method, the gas flow path
If clogging occurs, clean the lip if it does not move.
Is difficult. [0005] SUMMARY OF THE INVENTION The object of the present invention is to
Problems with the above prior art in the production of a blown nonwoven fabric
Point and eliminates the
Melt that improves productivity and does not reduce nonwoven fabric quality
An object of the present invention is to provide a blow spinneret. [0006] SUMMARY OF THE INVENTION The present inventors have achieved the above object.
To achieve the melt blow spinneret per row
After careful examination to increase the number of holes, the discharge holes
Installed in a zigzag arrangement in the direction
It has been found that it can be achieved by touching. That is, the present invention relates to a molten thermoplastic polymer.
Multiple ejections arranged in rows to eject body
Oblique injection of heated gas into holes and discharged molten polymer
Provided on both sides of the discharge hole array to make
Melt blow spinning with defined slits (a and b)
In the base, the discharge holes are staggered in two rows.
(1 and 1 ') and the distance from each of the ejection holes is farther
Of the discharge hole on the inclined surface (1b and 1'a) of the slit front wall
Grooves (2 and
2 ′) is provided.
It is a spinneret. Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 shows a melt-blown spinneret of the present invention.
It is a base bottom view which shows an example. Fig. 2- (A)
Section (a) is a cross-sectional view, and FIG.
It is sectional drawing in minutes. Here, 1 and 1 'are pierced in a zigzag
The discharge holes 2, 2 'correspond to the discharge holes 1, 1',
It has a slope provided on the slope front wall 1b, 1'a.
It is a groove to do. Also, a and b obliquely heat gas into the discharge holes.
It is a slit to be sprayed for [0010] As shown in FIG.
-The discharge holes 1, 1 'of the spinneret are
The holes are arranged in a zigzag pattern in two rows in the die width direction.
Two rows of discharge holes are in the same position relative to the base width, not in a staggered arrangement
When installed, the polymer is fused by the gas flow on the left and right sides of the base.
It is not preferable because it becomes easy. The port discharged from the discharge port
Rimmers are drawn and thinned by high-temperature and high-pressure gas flows
However, for example, as shown in FIG.
The gas flow paths (a, b) for (1) are asymmetrical on the left and right.
ing. The distance from the base slope to the discharge hole (1)
The gas flow (a) ejected from the closer gas flow path is
Sufficient for polymer, similar to conventional single-row outlets
The barrel is farther from the base slope than the discharge hole.
The gas flow (b) discharged from the gas flow path of
The velocity of the gas flow is large on the left and right because it does not sufficiently hit the polymer discharged.
The difference is different, and it is not possible to pull enough. That
Therefore, in the present invention, the gas flow (b) is applied to the base slope (1b).
Gas (2) in the vicinity of the discharge hole
Induces (b), generates sufficient traction, and can be ultra-fine
It works. The position of the discharge hole in the flat portion at the tip of the base is
It is appropriately determined according to the discharge hole diameter and the discharge amount.
0.15 to 0.50 mm is preferred. Less than 0.15mm
In the case of, processing is difficult.
It is difficult to obtain yarn and the process condition becomes unstable. Inside the discharge hole opening
The heart is in the flat part and the pressure resistance of the base and stable
It is preferable to form a fiber flow,
The shorter distance X and the diameter D of the discharge hole
It is preferable that D / 2 ≧ X> 0. D / 2 is distance
If it is smaller than X, it can give enough traction to the polymer
Can not. The discharge hole interval Z in the base row direction is the same as the conventional single row discharge.
It may be the same as the outlet interval, but if it is too small, air space
Poor pressure resistance when drilling body flow grooves,
Fusion also tends to occur. Improve productivity even if it is too large
Since it is not, 0.5 to 1.0 mm is preferable. On the slope of the base farther from the discharge hole
The cross-sectional shape of the gas flow ejection groove to be drilled is rectangular or curved.
Which can be adopted. In the case of a rectangle, the width W of the groove is 0.3 mm or less.
Above is preferably as large as possible,
It is necessary to secure the pressure resistance. The opening angle θ of the tip of the base is preferably 30 to 90 °.
Preferably, it is 45-60 °. θ less than 30 °
The base pressure is too low, and if it exceeds 90 °, traction
descend. The bottom of the jet airflow groove (2) and the base on the opposite side
The angle θ 'with the slope is θ <θ', and the inclination of the groove is
Set so that the inclination increases as it goes to the hole tip
In the groove, the jet air flow smoothly without stagnation (b)
Polymer with sufficient traction force
Can be given to. Discharge at the flat end of the base
The smaller the distance Y from the center of the hole opening to the bottom of the groove, the better
Good. If Y-D / 2 exceeds 0.5mm
Can give the polymer enough traction to get too far
I can't. It can be used for the melt blow spinneret of the present invention.
Polymers such as polypropylene and polyethylene
Which polyolefin, polyester, polyamide, poly
Various thermoplastic elastomers such as carbonate and polyurethane
Various thermoplastic polymers such as tomers can be used
You. As the preferred melt viscosity of these thermoplastic polymers
Is 100 poise or more and 2000 poise or less, and more
Preferably not less than 500 poise and not more than 1000 poise.
You. If the melt viscosity is too low, yarn breaks easily and polymer balls
It is more likely to occur, and the uniformity of the fiber diameter also becomes worse. one
If the melt viscosity is too high, it is difficult to reduce the fiber diameter.
Become. If necessary, a heat-resistant agent for the thermoplastic polymer,
Add additives such as antioxidants, weathering agents, and various pigments.
Can be. [0015] The spinning temperature of the polymer is the melting point of the polymer +
The temperature is preferably from 10 ° C to 100 ° C. If the temperature is too low
If the melt viscosity is too high, it is not preferable.
For this reason, long-term operation stability decreases. [0016] High temperature to draw and thin the discharged polymer
The compressed gas is preferably air or steam. Traction gas temperature
Is too far from the spinning temperature of the polymer
To influence the polymer spinning temperature-
10 ° C or higher and polymer melting point + 100 ° C or lower, more preferable
Alternatively, the spinning temperature of the polymer is +10 to 50 ° C. Ma
In addition, the gas flow rate is appropriately determined according to the target fiber diameter and the discharge amount.
As determined, the preferred flow rate is 1 cm in base width.
0.02 to 0.2 Nm per^Three/ Min. 0.02N
m^ThreeIf it is less than / min, the thinning does not proceed sufficiently and the resulting nonwoven
The spots on the cloth also become larger, 0.2 Nm^ThreeFiber / minute
Cutting is excessive, which is not preferable. Melt blow of the present invention
-When using a spinneret, use the
Fiber diameter equivalent to conventional without any need to increase gas flow rate
Of non-woven fabric with high productivity
It will improve. The gas is discharged and drawn by a high temperature and high pressure gas.
Fibers are collected on a collecting surface such as a net with suction.
It is obtained as a nonwoven fabric by depositing. Base of base
~ The distance between the collecting surfaces should be lower than the position where the fiber solidifies
The fibers do not fuse together, and the texture of the nonwoven fabric becomes coarse and hard.
This is preferred in that it does not. Collection surface is too low
When placed, fiber flow is disturbed by jet gas flow and accompanying flow
As a result, the fibers become entangled in a bundle and cause non-woven fabric spots.
Becomes The preferred distance is between 10 and 80 cm. [0018] The melt-blow spinneret of the present invention
The holes are arranged in a zigzag pattern in two rows in the width direction of the base.
To increase the number of holes per die and improve productivity.
You. In addition, by providing a groove on the base slope, each discharge
Enough traction gas flow hits the polymer discharged from the hole
The same per hole as the conventional base.
The texture and fiber diameter of the non-woven fabric that can be obtained even at the discharge rate and gas flow rate
And good ones can be obtained without change. [0019] The present invention will be described below by way of examples. [Example 1] Smell of the base shown in Figs.
And the die hole diameter (D) is 0.3mm, the opening angle of the die tip
(Θ) is 60 °, the angle between the groove bottom and the opposite base slope
Degree (θ ') is 65 ° and the groove depth at the flat end of the base is 0.
2 mm, groove width (W) 0.3 mm, discharge hole opening
The shorter distance (X) from the center to the tip of the flat part is set to 0.
1 mm, distance from the center of the discharge hole opening to the groove bottom (Y)
0.5 mm, distance between discharge holes in the base row direction (Z) 1.0 m
Use a base staggered in two rows with a size of
Polypropylene with a low index of 400 and a melting point of 165 ° C
At a spinning temperature of 230 ° C and a discharge rate of 0.15 per single hole.
g / min, and simultaneously pressurized air at 250 ° C with a mouth width of 1
0.1Nm per cm^ThreeSpouts out of the slit at / min
It was collected on a net placed 25 cm below the gold. Get
The average fiber diameter of the obtained non-woven fabric is 3μ, and the basis weight is 50 g / m. ^Twoso
The texture of the obtained non-woven fabric is good,
The output is 320m per meter of base length^Two/ Hr production efficiency
Met. [Comparative Example] A die hole diameter is 0.3 mm, a die tip
Edge opening angle (θ) is 60 °, from the center of the discharge hole opening to the base
The distance to the tip of the flat part is 0.1 mm, and the discharge holes are spaced
A set of bases installed in a single row in the length direction of the base at 1.0 mm
Used, with a melt flow index of 400 and a melting point of 165
° polypropylene at a spinning temperature of 230 ° C per hole
Discharge at a discharge rate of 0.15 g / min.
0.1Nm of air per 1cm of base width^ThreeSlits per minute
Spouted out onto the net placed 25 cm below the base
Collected. The average fiber diameter of the obtained nonwoven fabric is 3μ,
50g / m^TwoAnd adjusted the collection net speed so that
At this time, the output per unit time is 1 per meter of base length.
62m^Two/ Hr. [Embodiment 2] The same base as in Embodiment 1 was used.
Of polycarbonate with an average molecular weight of 15,000
285 ° C., compressed air temperature 320 ° C., base width 1 cm
0.08Nm^ThreeIn the same manner as in Example 1 with an air flow rate of
Non-woven on the net 15cm below the base
The cloth was collected. The average fiber diameter of the obtained nonwoven fabric is 4.5μ.
It is possible to obtain a flexible ultra-fine fiber non-woven fabric without any problems in the process.
did it.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a bottom view of an example of a melt blow spinneret according to the present invention. FIG. 2 is a sectional view of the base of FIG. [Description of Signs] 1 Discharge hole 2 Traction fluid grooves a, b Traction gas flow X Shorter distance between the center of the discharge hole opening and the tip of the flat portion Y The distance between the center of the discharge hole opening and the groove bottom at the flat portion Distance Z Distance between discharge holes in the direction of the base row W Width of traction gas flow groove

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-6-235111 (JP, A) JP-A-5-59605 (JP, A) JP-A-50-145608 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) D01D 4/02 D01D 5/098

Claims (1)

(57) [Claim 1] A plurality of discharge holes arranged in a row for discharging a molten thermoplastic polymer, and a heating gas is obliquely applied to the discharged molten polymer. Slits (a) provided on both sides of the discharge hole row for jetting into
And b) the discharge holes are staggered in two rows (1 and 1 '),
In addition, as the distance from each of the discharge holes increases toward the front end of the discharge hole, the slit front wall slopes (1b and 1'a) which are farther away.
A melt-blow spinneret characterized by being provided with grooves (2 and 2 ') whose inclination increases.