JPH06506734A - Oriented melt-blown fibers, methods for making such fibers and webs made from such fibers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Drawn melt-blown fibers, methods for making such fibers and such fibers Web technology field made from fiber The present invention provides melt blown fiber webs, i.e. melt blown fiber forming materials in a die. A high velocity gas stream through the orifice (which impinges on the extruded material and to an average microfiber size typically on the order of 10 micrometers or less. pertains to webs made by extrusion into a material that is attenuated.

Background technology Melt-blown fibers have a wide range of commercial applications, including filtration, battery electrode partitions and insulation. Over the past 20 years, very small diameter fibers have been used in the body. and the need for webs with good tensile strength has become recognized. however , the tensile strength of melt-blown fibers is low, e.g. It has always been observed that the fabricated fiber is weaker than that of the manufactured fiber (paper Melt-Blowing--A One 5tep Web Processes s For New Nonwoven Products” Robert R, Buntin and Dwight, Lohkca Steel p, Volume 56, No. 4, April 1973, Tappi, page 75, columns 2 and 3), late In 1981, the industry generally recognized that melt-blown webs are inherently , the fineness of the fibers is polished to result in strong fiber strength. Regarding conventional nonwoven webs made by melt-spinning below the melting point of polymers, (Article rTech) nical Development In TheMelt-Blowing ProCess And itS Applications In Abs orber+tPro-ducts 1Ilr, W, John McCull ochaDr, Robert A, Van Brederode.

Ir+sight '81. r, opyrigl+t Marketing/T technology 5service, Inc.

Kalahl;1zoo, Ml, j,’i1B, Heading! 7’Strength The weak strength of tb (see section J) and melt-blown soybean A serious attempt was made to limit the usability and eliminate the weak strength of It has been done.

Such research is described in U.S. Patent No. 3.704.198 to Prpntice. 1,'H,,y7) At least a portion of the melt-blown jaw (,1, Rolling or point joining - 1 - fusion chair 1 - coil. Rolling j: Therefore, wave strength Level: Slightly improved from 1::, but the strength is still C, and the -2 is all Physical strength is weaker than expected.

Other conventional research has shown that before collecting Utbu, 711 components with strong strength - 7-y Melting blowing of Iha-7 eye? Add to ＼-. 2 or melt blowing 7 14 Strong support, e.g. spunbond (U.S. Pat. No. 4.0.41,203 1. No. 4,302,495 and Bi:S4. , +96.245￥j′S:4”’I!(((Z>J:　::?,) ,,1. s　%) y　　　I　is more expensive. “)-,’-1 Licney, 1-:, 7-Toy ＼-′↑! 1F clothes…wa l±, ( 〃-1 Many objectives (1)〆11. Me I, 7. ,, jJ Sense li' Taru J) So’:tir”.

;7,,,+,(C'-'s +5: (-(-Seki 1, (Jl,'R'BH a　11y〼r+r　US time 2 (th, 1, +18.531'j,'i　X;l i　+,'j column) h sibi K) i old ld. No. 2 5th and 6th system) (51 entry (+) jisu, -1, * (1, T, , r is　,,’r,na IX- and extremely high 14-sha l, two Tsui 7(,’l), l’・,’,jl　)Vl. There is a recognition-')L'+h7. j, ka(-5, As recognized by If　a　　　　s　e　r　　　　　　　　　　　　　, A part of a molten soft body with a uniform diameter. 11 Despite the ability to do so, the fiber size distribution is 1 to 2 microphones when using a fiber with an average fiber diameter of 6 to 8 meters Fibers in the micrometer range are present (Examples 5-7). Bu above The larger diameter "shock" described in Ntin et al., p. There is also the issue of reducing the number of "cuts". The shot is impinged on the air in the melt-blowing process. It occurs when the fibers break in the turbulent flow of the source. Runtin is this show shows that the cut is unavoidable and its diameter is larger than that of the fiber j2 ,ing.

U.S. Pat. No. 4,622,259 to McAtaish et al. A melt-blown fiber that is said to have improved strength and is particularly suitable for use in Regarding the web. These webs are made from fiber molding material through a melt-blown die. The T is created by introducing secondary air at high speed near the point where it is being extruded.

As best seen in Figure 2 of this patent, this second air passes through the melt-blowing die. This second stream is introduced from both sides of the leaving melt-blown fiber stream. '7- is introduced in a generally perpendicular path to the fiber stream.

This second air collides with the fiber forming material r1 to form fibers. 7, and this second ′f air joins the fiber path h′ (, 2 changes direction to a more parallel direction -. The combined first, ! - second air is Next, the fiber is transported to the collector. At this time, rI speaks, By using the secondary air, the A long fiber is formed, and the fiber 177' is ``G,'' during fiber recovery: Shows fewer autogenous bonds. Due to the nature of this successor, what this patent describes is It is recognized that the strength of each fiber is strong. This strength is the degree of molecular orientation It is suggested that G depends on the -27 lines), i.e. The high-speed secondary air used in the zero T process is the time when the fiber is made fine. The cooling effect of this second air is due to the fact that the fiber is The molecular orientation of the fiber is extreme due to its deceleration during collection on the clean. The aim is to increase the possibility that the situation will not be alleviated.

The fabric is collected and embossed into a web or chemically binder applied to the web. --- and this fabric has greater strength, e.g. Minimum gripping tensile strength of 0.8 N/g/m” or more, to weight ratio, and 0.04 N/g /m” minimum Elmendorf tear strength to weight ratio It has been reported that - has.

These fibers have been reported to have a diameter of less than 7 micrometers. There is. However, this method has a narrow fiber diameter distribution or 2.0 micrometer or It has not been shown to result in fibers that are substantially free of shot.

Disclosure of invention The present invention provides a greatly improved size distribution of Noah Iher diameter, average fiber diameter, and fiber diameter. new melt-blown fibers and and fibrous webs. This new melt-blown fiber is similar to traditional melt-blown fibers. It has much better orientation and crystallinity than var. Once loaded, the fiber-forming material is passed through the metering means and then through the orifice of the die. In a controlled high-velocity gas stream that rapidly attenuates the extruded material t4 into fibers. extrusion of this attenuated fiber and gas stream to the first open end, i.e. is placed near the die and the attenuated fiber leaves the die. into the inlet end of a tubular chamber extending in a direction parallel to the We introduce air into the chamber with both radial and annular components. The air that is blown along the axis of the chamber moves the fibers into the chamber. (with sufficient velocity to maintain it under tension as it passes), and preferably is perpendicular to the longitudinal axis of this chamber over substantially the entire length of this chamber introducing air in the direction; optionally, inserting the attenuated fiber into a second tubular chamber. where the quenched fiber is blown along the axis of this chamber. further stretched by the air being held; and the opposition of this last tubular chamber. or collecting the fibers after they emerge from the exit end. This is the result of manufacturing according to the method.

Typically, this tubular chamber is a thin, wide, box-like chamber (generally is slightly wider than the width of the melt-blowing die). Orienting air It is generally introduced into this chamber at an angle to the path of the extruded fiber. However, it passes near a curved surface at the first open end of this chamber. Coanda ( Due to the (:oanda) effect, this stretching air flows over this curved surface in a layered, non-turbulent state. This causes the extruded fiber to traverse the path traveled, and this fiber Combines with the 1st Air, which takes Ivar away. Traverse the extruded fiber into the chamber The amount of radial flow component of air that is useful for directing or directing changes the radius of the Coanda surface. It can be adjusted by The large radial flow area is centered on the axis of the chamber. Responsible for better orientation of fibers. A small radius Coanda surface makes the fiber axial flow component of air effective to traverse or direct into the centerline of the axis of the chamber lower the relative amount of However, the strong axial flow from the Coanda surface with a smaller radius components tend to increase the stretching force of the air on the fibers in the chamber. . Generally, a Coanda surface with an unlimited radius range may be utilized. But long As the radius decreases to 0, the angle becomes sharper, and the air becomes more They tend to move away from each other. Radius as small as 1/8 inch are available and generally 0.5 to 1.5 inches.

Preferably, a second vertical cooling stream of air is introduced along the length of the chamber. Ru. This air is preferably in this channel facing the fiber exiting the die. It is introduced into the chamber in a diffused state through the two opposing walls of the chamber. this for example, by having a side wall at least partially made of a porous glass composite. It can be accomplished. This vertical air also prevents stray fibers from reaching the chamber walls. Guide the fiber to the center of the chamber while preventing it from sticking. these The fibers are directed into the chamber in an orderly and compact stream. And it remains compact throughout the chamber. one chamber Preferably, the desired tubular chamber is circumferentially circumferential at its exit end. Sideward drawing air and vertical cooling air generally cool the fibers. (This drawing air stream may be heated, but is usually An atmosphere that is unheated and has a temperature below about 35°C; in certain circumstances This allows stretching air or vertical air to be introduced into the stretching chamber. cooling to ambient temperature before use), this cooling effect is generally desired because it accelerates the solidification of the fiber under drawing conditions and Because it strengthens the power. Furthermore, the stretching air passes through the stretching chamber. Its tensile effect is used to impart orientation to the solidifying fibers. can. The fibers are usually slightly cooled at this point, which further improves their orientation. It is possible to use higher air pressure to impart greater tension to this fiber. Wear. Diffused vertical airflow ensures low tackiness of the fibers within this chamber. However, vertical air can be utilized, although this is not very necessary.

Molecular orientation and crystallinity of the fibers of the present invention compared to conventional melt-blown fibers The oriented fibers of the present invention (Photo A) and the prior art non-oriented -AXS (wide angle This will be explained with reference to Figures 4.7°8, 10, and 11, which show photographs (ray scattering). photograph The annular feature of the optical region in B indicates the high crystallinity of the photographed fiber of the present invention. and ring interference implies that there is a significant crystal orientation.

Brief description of the drawing Figures 1 and 2A and 2B illustrate the method of the present invention being carried out to produce the fabric of the present invention. 1A and 1B are side and perspective views of various devices useful for.

Figures 3.5 and 9 show the fiber of the invention (drawing “A”) and the comparative fiber (drawing “A”). FIG.

Figures 4.7, 8.10 and 11 show the fiber of the invention (photo "A") and the comparative fiber. 6 is a -AX photograph of fiber (photo "B"); and FIG. 6 is a representative fiber of the present invention. Scanning electron micrographs of web (6A) and comparative fibrous web (6B).

Figure 12 shows polymer flow rates for continuous ultramicron (submicron) fibers. , versus fiber diameter.

FIG. 13 is a scanning electron micrograph of the ultramicron fiber of Example 33.

detailed description Representative examples useful for making blown fibers or blown fiber webs of the present invention The apparatus is illustrated in FIG. The part of this equipment that forms the blown fibers is nte, νan^,’5uperfine ThermoplasticFi bers” Hariustrial Eni-neeriHqhemist, r7 Volume 48, page 1342 Iryo (1956), or Wente+V, A,; B oone, C, D; and Fluharty et al., E, L, May 25, 1954. Naval Research, aboratories report released in Japan No. 4364, title: Manufacture of 5uperfine O rganic Fibers J. The equipment shown The section includes a die 10, which includes a series of laterally parallel die orifices. 11, one of which is seen in a cross-sectional view across this die. O The orifice 11 passes from the central die cavity 12.

From extrusion II (not shown), the fibers are introduced into die cavity 12 through opening 13. Introducing the iber forming material. Air installed on both sides of the row of orifices 11 - Gear knob 15 transports heated air at a very high speed. It is called the first air. This air impinges on the extruded fiber-forming material and then on the extruded material. Attenuates the material by pulling it into a mass of fibers. This first air is generally heated , and is supplied to both air gaps I5 at approximately the same pressure. this air - also preferably to prevent dirt or dust from interfering with uniform fiber forming. is filtered. This air temperature is generally lower than the temperature of the molten polymer in the die orifice. Also maintain high temperature. Preferably, the air is at least as high as the temperature of the melt. 5°C higher. Temperatures below this range will cause the polymer to leave the die as it exits the die. This can cause excessive cooling and make stretching in the chamber difficult. too high temperature Intensity can cause excessive polymer degradation or increase the tendency for fiber breakage.

From the melt-blowing die 10, these fibers enter a first tubular drawing chamber 17. is carried. "Tubular" as used herein refers to having an open end at opposite ends of each shaft. , means any ring-shaped structure whose axis is covered by a wall. In general, Chan The bar is a rather thin, wide, box-like chamber, slightly wider than the width of die 10. width, and the stretching air flows smoothly across the chamber without slowing down. 1 minute for the fibrous material extruded from the die to flow into the chamber. The height that it takes 1-minute to travel across this chamber without touching the walls 18) in Figure 1. If the height is too high, maintain tension application air velocity. This would require an unnecessarily large amount of air to hold it. solid wall chamber 1 Good results for 7 are obtained for heights of about 10 mm and above, and we found that for about 25+ It has been found that a height of 1 m1 or more is not required.

The walls 26 across the width of the chamber 17 may be comprised of an air permeable or porous material.

A second cooling diffused air stream may be introduced across the width of the chamber. child The air flow prevents solidification and/or crystallization of the polymer in the cooling chamber 17. Improved functionality. This second cooling air also cools the fibers in chamber 1. 7 and away from the wall 26. However, this cold The air pressure in the cooling air stream is high enough to cause turbulence in the chamber. It shouldn't be expensive. Generally, pressures between 2 and 15 PSI have been found to be acceptable. ing.

The stretching air is used to cause the Phino 1- carried in the first air to enter the chamber. The drawing tip is inserted through an orifice 19 located near the first open end of the chamber into which the It is introduced into the chamber 17. The stretching air is preferably called a Coanda surface. From both sides of the chamber/s+- (i.e., from both sides of the chamber/s+- from the opposite side of the fiber stream). The polymer used has low crystallinity Larger radius Coanda surfaces are preferred when or have slow crystallization rates. Furthermore, when using a low crystalline polymer, from the orifice adjacent to the Coanda surface, Preferably, the air exits at an angle perpendicular to the annular center line of the chamber. At a zero angle, this air is parallel to the annular center line and cannot exit the orifice. Yes, in general, the air discharge angle for stretching can be changed from 0 to 90 degrees, but Larger angles are also possible. An air discharge angle of 30 to 60 degrees is generally preferred. Something interesting has been discovered. A smaller stretching air discharge angle When using a quench chamber or melt blowing highly crystalline polymers before sometimes allowed.

The drawing air introduced into the chamber bends as it exits the orifice. , and moves around the Coanda surface to create a main axial flow along the longitudinal axis of the chamber. Ras. Air movement is fairly uniform and rapid, and this A. Pull the fiber extruded from 10 into the chamber in a uniform state. . Fibers exiting the melt-blown die are generally slightly wider immediately after they leave the gouer. Vibrating in a wide pattern, the fibers exiting the melt-blowing die in the method of the present invention The bars pass uniformly into the center of this chamber with an amazing plane-like distribution, resulting in a remarkable It tends to move longitudinally across the chamber without vibration.

After the fibers exit the chamber 17, they generally form wavy line segments 21 and dotted lines 22. (This shows the general exterior of the fiber stream) shows the vibrational movement shown.

This vibration results from expansion or flaring at the outlet of chamber 17. But long This vibration tends to occur when it is near the melt-blowing die orifice. Does not cause significant fiber damage. The drawing chamber improves the strength of the fiber. post-chip, even if accompanied by an increase in the peak stress to which the fiber is exposed. Chamber vibrations can be withstood without fiber damage.

As shown in FIG. 1, regarding the aspect of the single stretching chamber 17, this chamber 1 7 is preferably flared at its outlet end 23.

This tail widening allows the fibers to flow through the fiber stream without fiber breakage. was found to result in a more random or isotropic arrangement. For example, wide hem The recovered web of fibers of the present invention passed through a chamber having no outlet. tend to have a pattern of directional fibers (i.e., more fibers parallel to the direction of movement of the collector rather than aligned transverse to it (They tend to line up in the same direction). On the other hand, it is collected from a chamber with a flared outlet. The fiber web is more densely balanced in the device and laterally. . This flare is in both the height and width dimensions, i.e. the axis or plane of the drawing More typically, this tail spread may be both in the plane perpendicular to the page. axis in the plane of the drawing, i.e. the thickness of the fiber stream passing through the chamber The spread (angle θ) is ideal for achieving smooth isotropic loading of the fibers. It is believed that there is. Length 24 of the part of the chamber with the flared hem (this is the length of the chamber (which may be called the randomization part of the member) depends on the speed of the drawing air and the frame to be produced. Depends on fiber diameter. For slower speeds and smaller diameters, shorter lengths are advantageous. used. A tail spread length of 25-75C- has been demonstrated to be useful. .

The drawing air is applied as the fiber moves longitudinally across the chamber 17. Enter the drawing chamber at a high enough velocity to keep it under tension. This cha Continuous horizontal movement across the fiber means that the fiber is continuous and that the stress line segment Indicates that it is under tension. The air speed required for stretching (this is the The pressure of the air introduced into the chamber and the orifice or gap 19 (determined by size) depends on the type of fiber forming material used and the fiber varies depending on the diameter. In most cases, the pressure is about 70 PSI (about 500 kPa) and gear width for orifice 19 of 0.005 inch (0,013 cm) (dimension 30 in Figure 1) is optimal to ensure adequate tension. It was found that However, with the above gap width, some poly For example, 20-30 PSI for nylon 66 (140-200 kP a) Very low pressures are used. If chamber 17 is an elephant as soil, cold chi If used as a chamber, a pressure as low as 5 PSI should be used for drawing air. Can be used.

Surprisingly, most of the fibers are on either the top or bottom side of this chamber. can pass through the chamber over long distances without touching any . However, in the first chamber (17 or 37), the side wall of the chamber Introducing a second cooling airflow perpendicular to the fiber in a diffused state through This second cooling air flow is preferably used to preferred for polymers because they have higher adhesion and therefore the fibers are less likely to drift. This is because they tend to loose and adhere to the side walls of the chamber.

This cooling airflow also strengthens the fiber strength through its cooling effect, Reduces the tendency for any fiber breakage before or after the first chamber (17 or 37) Ru.

These chambers are generally at least about 40 cm long (shorter chambers at a lower production rate or when the first chamber is primarily used as a drawing chamber. ) and preferably the desired orientation and at least 100 c- to achieve the desired mechanical properties. Shortish When the chamber length of It can be used. The entrance end of the first chamber is generally within 3-10 cm, And as mentioned above, there is typically a disruptive turbulent flow near the exit of the melt-blowing die. Despite this, these fibers enter the chamber in a unified state. I'm drawn into it.

After exiting the drawing or last chamber (17 or 38), the solidified fiber is reduced. While speeding up and slowing down, they flow as a web 27 onto the collector 26, It is collected as a mass of randomly oriented fibers that are intertwined as much as possible. this The collector is a cylindrical screen with fine holes, a drum, or a rotating It may take the form of a mandrel or a moving belt. Gas recovery equipment helps build up and remove gas. May be placed behind the collector to be useful.

The recovered web of fibers can be removed from this collector and or winding onto a storage roll with a liner separating adjacent windings on the roll; During fiber recovery and web formation, these fibers are completely solidified and distributed. towards These two characteristics tend to make the fiber have a high modulus. The fibers are highly elastic and therefore highly elastic enough to create a manageable cohesive web. It is difficult to slow down and untangle the bar. Stretched melt extruded fiber The web comprising fibers has the cohesive strength of a conventional melt-blown fiber recovery web. For this reason, fiber recovery webs are typically divided into sections, e.g. or by homogeneous rolling at points (generally about 5-40% section). are joined together to form an integral manageable web; or For example, hydraulic entanglement t) Ultrasonic bonding of the web, binder to the fibers in solution or molten state The fibers are melted together, adding the material and then solidifying this binder material. Adding solvent to the web or preparing secondary component fibers for agent bonding and then subject the web to conditions that cause the components to fuse adjacent or intersecting fibers. directly into the device that integrates the web into a cohesive structure by fusing the webs with each other. supply You can also connect this collection web to another web, for example on top of this collector. may rest on the moving web; also on the uncoated side of this collecting web. A second web may be passed over the collection web, which may be a carrier or cover web. or not attached to the liner, or by thermal or solvent bonding, or attached to the web or liner by bonding with a further binder material; good.

The blown fibers of the present invention are microfibers with an average diameter of about 10 μm or less. Preferably, fibers of this size provide improved filtration efficiency and other Responsible for advantageous properties. Very small diameter, on average less than 5 μm, even less than 1 μm Fibers can be blown, however, e.g. Larger diameter fibers can also be blown, and these are used for certain purposes, e.g. For example, it is useful for coarse filter webs.

The present invention is advantageous in forming fibers with small fiber sizes; Fibers made according to the present invention generally include fibers such as those used in the present invention. Fibers made using conventional melt-blowing conditions without the use of a drawing chamber. The diameter of the rim is small. Additionally, the melt-blown fibers of the present invention have very narrow fiber diameters. For example, the present invention has a fiber diameter of 5 μm or more on average. In the web sample, the diameter is typical of conventional melt-blown fibers. Contrary to the larger dispersion, more than 3/4 of the fibers, in fact more than 90% The upper diameter tends to be in the range of about 3 μm. Average fiber diameter is 5μm In preferred embodiments, the diameter is less than or equal to about 2 μm, and more preferably less than or equal to about 2 μm. The largest fibers differ by up to about 1.0 μm from the average value, and generally 9 0% or more of the fibers are in the range of 3.0 μm or less, preferably about 2.0 μm m or less, and most preferably in the range of 1.0 μm or less.

Extremely small average diameter, generally less than 2 μm on average, and very narrow fiber diameter. (for example, 90% belongs to the range of 1.0 μm or less). A suitable embodiment is shown in FIG. 2A. The fiber forming material from the extruder 30 is into a metering means comprising at least a precision metering pump 31 or a purge, etc. let For very small diameter, regular, virtually continuous fibers, Generally, the flow rate of this polymer through each orifice in the die should be slowed considerably. Suitable polymer flow rates for most polymers are 0.01~ 3g+II/hr/orifice and an average diameter of less than 1 or 2 μm. The fiber diameter is preferably 0.02 to 1.5 gm/hr/orifice.

To obtain such low flow rates, conventional extruders require Even if the screw is at a low rotational speed, the screw should be operated at a low rotational speed. This is a little wavy resulting in polymer flow rate. This slight flow undulation results in a very small diameter Having a significant detrimental effect on the size distribution and continuity of melt-blown fibers was discovered.

Preferably, a system of three precision pumps is utilized as the metering means as shown in Figure 2A. Ru. Pumps 32 and 33 split the flow from metering pump 31. pump 32 and 31 may be operated by a single drive, in which case these pumps are connected to each other. is operated at a constant ratio to With this equipment, the speed of the pump 33 can be adjusted to Providing polymer feed at a constant pressure to pump 32 measured by a force transducer continuously adjusted to Pump 33 typically removes excess water from the extruder and pump. Serving as a purge to remove excess polymer feed, the pump 32 leads to the die 35. Provides smooth polymer flow. To feed the polymer into a series of dies Multiple pumps 32 may be used. Preferably pumped to remove any impurities. A filter 34 is provided between the pipe 32 and the die 35. Preferably, this frame The mesh size of the filter is 100-250 holes/inch2 or more. This system Preferably, the polymer is operated at a flow rate as slow and substantially non-waving as necessary. Other facilities feeding the refice are possible.

For example, the hypothetical model shown in Figure 12 (where the y-axis is the resin flow rate (duram/min) /orifice), and the y-axis represents the logarithm of the two fiber velocities (upper 400 m/s for the line segment and 200 m/s for the lower line segment) 0.9 isotropic polypropylene fiber diameter in microns) feed the die at the appropriate flow rate/orifice to create the desired fiber diameter. . This model is designed to reduce the flow rate to create uniform diameter microfibers. As can be seen here, the method of the present invention can be used to obtain very small average diameters. To make continuous microfibers, very slow polymer flow rates are required. Ru. The total theoretical polymer feed rate to the die will depend on the number of orifices. . This suitable polymer feed rate is provided, for example, by metering means. But long At such low polymer flow rates, continuous, high strength, small diameter fibers can be produced. The method of the present invention for obtaining bars is not known or can be achieved by conventional melt blowing techniques. It is not possible to measure P.

The appropriate refrigeration diameter for making fibers with a uniform average diameter of 2 μm or less is 0.0. 25~0.50m5, and 70.025~0.05 is preferable (for example, C eccato 5pinnerets, Milan, Italy or Kas en Nozzle Manufacturing Corporation+ Ltd., +0saka+ Japan).

Suitable aspect ratios for these orifices are in the range 200-20; 100-20 is preferable. High orifice density regarding preferred orifices is preferable to increase the amount of polymer charged. Generally, orifice density of 30/c lock is preferable, and 407 cm or more is more preferable.

When making uniform fibers with an average diameter of 2 μm or less, the pressure of the first air is lowered. polymer melt extruded through the die orifice to reduce the tendency for fiber breakage. Attenuate and pull the stream. Generally, the air gear knob width is approximately 0.4++n. Regarding this, an air pressure of 10 Ibs/inch” PSI (70 kPa) or less is preferable. and more preferably less than about 51 bs/inch t (35 kPa). The air pressure reduces turbulence, and the turbulence created by melt blowing causes the fibers to Blow this continuous fiber into chamber 17 or 37 before splitting. make it possible. The continuous fiber delivered to chamber 17 or 37 is (in chamber 17 or 37 and/or 38). Inside). The temperature of the first air is preferably close to the melting point of the polymer (for example, (approximately 10°C higher than the melting point of remer).

These fibers are removed from the melt-blown die to maintain proper stress-line tension. Must be tensioned by the first and/or second chamber at the exit of the interface. No. These chambers (17 in Figure 1 and 37 in Figure 2A) and/or 38) the melt-blown fibers typically encountered at the exit of the melt-blown die. These fibers are protected from vibrational effects. fibers are random These fibers break when subjected to these vibrational forces for the purpose of It is strong enough to withstand this force without any damage.

The resulting drawn fibers are virtually continuous and can be obtained by scanning electron microscopy. When looking at the microfiber web, no fiber tips were observed. won.

From the fiber-forming orifice, the fiber-forming material is transferred to chamber 17 or 37 (which can be used with or without chamber 38) As explained above, the particles are entrained in the first air, then in the stretching air and the second cooling air. be done. In the preferred installation, the material exits chamber 37 and continues into chamber 3. It is refined in 8.

Tubular chamber 38 functions similarly to chamber 37. the second chamber 38 When used, this chamber is primarily used for stretching, in which case 0.00 Regarding gear tooth width of 5 inch (0.13 mm) air orifice (not shown) The air pressure is -1 to at least 50 PSI (344 kPa), preferably is at least 70 PSI (483 kPa). This second chamber 38 When used, the corresponding pressure in the first chamber 37 for the same gear width will generally be 5 PSI = 15 PSI (35-103 kPa). this place The first chamber 37 in this case mainly functions as a cooling chamber and has some orientation. will occur.

The second thousandth chamber 38 is generally located 2-5C- from the exit of the first chamber 7; In this case, the 1,000th yanbar would not be widened as described above. The dimensions of the second chamber will be that of the first chamber 37.

The randomization of the fibers is performed by increasing the fiber width just before reaching the exit 40. Further enhanced for earth stream usage. This is supplied from the chamber This can be done by an entangling air stream.

This entangling air stream is located at the sidewall and preferably at the chamfer. is fed (preferably laterally) through an opening near the outlet end 38 of the chamber 38. Ru.

Such an air stream may also be used in equipment such as that described in FIG.

The above embodiments primarily involve extremely small diameter, substantially continuous fibers, e.g. Fibers with an average diameter of 2 μm or less, with a very narrow range of fiber diameters. , and used to obtain fibers with strong fiber strength. My This combination of properties in black fiber webs is unique and allows for filtration and Highly desirable for applications such as insulation.

As previously mentioned, the drawn melt-extruded fibers of the present invention are believed to be continuous; This is clearly the case with conventional melt-blown fibers, which are generally said to be discontinuous. Fundamentally different from process-made fibers. These fibers are transported to the drawing chamber (or cooling and then drawing chamber) without and then generally moves without interruption across the drawing fiber. these The chamber introduces stress line tension, which causes the fiber to reach a remarkable degree. and significant vibration of the fibers until they are fully stretched. Prevent fiber tip or shot (fiber breakage) in zero collection web solidified spheres of fiber-forming material, such as those produced when the tension is released. If released, this material would allow the material to shrink.) I couldn't. These characteristics apply even when the average fiber diameter is 2 μm or less. This is due to the extremely small diameter of the low strength exiting the orifice of the die. This is extremely remarkable from the perspective of the polymer flow dream. Furthermore , the fibers in the web exhibit little, if any, thermal coupling between the fibers. did.

Other fibers may be incorporated into the fibrous web of the invention, e.g. After the ream leaves the last tubular chamber and before it reaches the collector , can be combined by supplying other fibers. US Patent No. 4,118,531 discloses crimping that increases the loft of the collection web. Methods and methods for introducing stable fibers into a stream of melt-blown fibers and such methods and apparatus are suitable for the fibers of the present invention. It is useful. U.S. Patent No. 3,016,599 introduces non-crimped fibers. We will teach you how to do this. Additional fibers can be used to fill gaps or slack in the web, This can be a function of increasing the porosity of the web and changing the fiber diameter in the web.

Additionally, the additional fibers can function to impart cohesiveness to the collected web. example fusing fibers, preferably at a temperature lower than the fusing temperature of the other components. A secondary component fiber having a component can be added, and this fusible fiber The bars can be fused at fiber intersections to form a cohesive web. Furthermore, Crimping stablef to web as described in U.S. Pat. No. 4,118,531 It has been found that the addition of fibers will result in a cohesive web.

The crimped fibers provide cohesion and retention to each other and the drawn fibers to the web. Intertwined to provide wholeness.

A web comprising a blend of crimped fibers and drawn melt-blown fibers (e.g. preferably up to about 90% by volume and preferably about 50% by volume. web) has numerous other advantages, especially as an insulating material. It has advantages regarding the use of

First, the addition of crimped fibers makes the web bulkier or more elastic; That increases the insulation properties. Furthermore, this drawn melt-blown fiber has a small diameter and narrow They tend to have a distributed fiber diameter, and both can improve the insulation quality of the web. and because they contribute a large surface area per volume unit of material It is. An additional advantage is that these webs are made of unstretched melt-blown microfiber is more flexible and drapable than a web comprising The obvious reason for this is the lack of thermal coupling between the recovered fibers. . At the same time, because of the strong strength of the drawn fibers, and the orientation of the fibers, it This web is non-woven to make it more resistant to high temperatures, dry cleaning solvents, etc. It's always about durability. This latter advantage is due to the fact that it is made by conventional melt blowing procedures. The properties of polyethylene terephthalate tend to be amorphous. Of particular importance to bars. When exposed to high temperatures, amorphous polyester Rimmer can crystallize to a brittle state, which is a durable material in textile applications. There aren't many. However, the drawn polyester fibers of the present invention are similar to those can be heated without deterioration of its properties.

It has further been discovered that the lighter weight webs of the present invention are made from unstretched melt-blown fibers. The advantage is that it can provide the same insulation value as a heavier web made from bars. The reason One reason is the smaller diameter fibers and narrow distribution in the web of the present invention. The fiber diameter of the present invention is as described in U.S. Pat. No. 4,118,531. results in a larger effective fiber surface area in the web and a larger This is because the surface area of will effectively hold more air there. per unit weight Larger surface areas have also been achieved due to shot and ``ropi ng) J (as occurs in conventional melt blowing through entanglement or thermal bonding) This is because there are no clusters of fibers.

Agglomerated webs combine oriented melt-blown fibers with non-oriented melt-blown fibers. It can also be made by Figure 2B shows the device for creating a loose composite web. and this has the structure of die 1° shown in FIG. 1 (and also die 35 in FIG. 2A). extrusion from the first and second melt-blowing dies 10a and 10b and the first die 10a. comprising at least one drawing chamber 28 through which the drawn fiber passes. Ru. This chamber 28 is similar to the chamber 17 shown in Figure 1 and the chamber in Figure 2A. - Similar to 37 and 38, but with randomization of the tip of this stretching chamber. Portion 29 has a different spread than randomized portion 24 or 40 shown in FIGS. 1 and 2A. has. In the device of Figure 2B, this chamber expands rapidly to higher elevations. and that part narrows slightly all the way to the exit. Such a chamber is Endows the web with improved isoforce properties, but with a more sloped hem of the chamber as shown in Figure 1. The spread confers more isotropic properties.

The polymer introduced with the second die I0B- is formed by the first die IOA. Like fibers, they are extruded through a series of orifices to form fibers. However, the finished fibers exit the drawing chamber 28 as a fiber stream. introduced directly into the . The ratio of drawn to undrawn fibers can vary greatly. and fiber properties ff (e.g. diameter, fiber composition, secondary components) properties) can be changed as desired. Has good isotropic balance properties For example, if the tensile strength of the web in the transverse direction is less than the tensile strength of the web in the machine direction, A web that is at least about 3/4 full can be created.

Some webs of the invention include particulate matter, e.g. to provide improved filterability. , which was introduced into the web in the manner disclosed in U.S. Pat. No. 3,971,373. sell. This additional particle may or may not be bound to the fiber; this is an example For example, by adjusting processing conditions during web formation or by post-heat treatment or shaping operations. Furthermore , the additional particulate material is, for example, a superabsorbent material as described in U.S. Pat. No. 4,429,001. It's possible.

These fibers can be made from a wide variety of fiber-forming materials. Can be done. Typical polymers for making fused fibers include polypropylene; Includes polyethylene, polyethylene terephthalate and polyamide. Nairo Nylon 6 and nylon 66 are particularly effective materials because they have very high strength This is because the fibers of the same degree are formed.

The fibers and webs of the present invention are electrically charged to enhance their filtration capabilities. 4,215,682, which may be applied to the fibers as they are formed. by introducing a charge into the formed web in the manner described in U.S. Pat. , 571,679; No. 4,375,718, No. 4,588,537 and No. 4,592,815 See also, polyolefins, especially polypropylene, are used as charged fibers of the present invention. are desired to be included as components in This is because it holds.

The fibrous web of the present invention may contain other components in addition to microfibers.

For example, a fiber finish can be placed on top of the web to improve its feel. May be sprayed. Additives such as colorants, pigments, fillers, surfactants, abrasives, Light stabilizers, flame retardants, astringents, pharmaceuticals, etc. may also be added to the web of the present invention; By introducing them into the fiber-forming liquid of microfibers, may be added to the fibers during fiber formation or after the web is collected. By spraying onto the bar.

The finished web of the present invention may vary widely in thickness. In most cases, the web is about 0 ．． It has a thickness of 0.05 to 5.0 cm. For some applications, two or more pieces The separately formed webs may be assembled into a single thick sheet product.

The invention will be further described with reference to the following examples.

Example 1 Using the apparatus shown in Figure 2 except for the second holder Ob, the drawn microfibers are Ren resin (formerly mont PF 442; Himont Corp, Wi lming-ton, Delaiiare; 800-1,000 It was made from the melt flow index (with MP value). The die temperature is 200'C, and The temperature of the first air was 190°C. The first air pressure is 10PSI (70kP a), and the gap width at the orifice is 0.015 to 0.018 inches ( 0.038 to 0.046 CI). Pass the polymer through this die orifice. Approximately 0.009 bond/hour/orifice (89g/hr/orifice) Extruded at a degree.

From this die, the inner height is 0.5 inches (1.3 cm) and the inner width is 24 cm as shown in Figure 2. inch (61 cm) and 18 inch (46 cm) long box-like tubular drawing chamber The fiber was pulled across the Randomization or expansion of this chamber 29 is 24 inches long (61c+g) and has a chamber as shown in the drawing. The stretching chamfer is widened at 90' with respect to the wall portion defining the main portion 28 of the consists of a large area wall section that defines the chamber; this wall is the main part of the chamber. flares out to a height of 6 inches (15,24 cm) at their junction with the , and 5 inches (12,7 cm) down to its length of 24 inches (61 cm). +) has narrowed to a height of +). The second air having a temperature of about 25°C is heated to 0.0°C. An orifice with a diameter of 5 inches (0,013C11) 19) at a pressure of 70 PSI (483 kPa). I blew it into Yanno 1-.

The finished fiber exits the chamber at a speed of approximately 5644 m/min and is ladleed from the die. A screen 36 inches (91 cm) away and moving at a speed of approximately 5 m/min) Collected on top of a bottle-type collector. These Phi Noi range from 1.8 to 5.45 miku lon diameter and had an average diameter of about 4 microns. Fiber Nitsu The exit speed/stretch ratio (ratio of exit speed to initial extrusion speed) was 11,288. , and the diameter draw ratio was 106.

The tensile strength of the fibers was measured using an Instron tensile tester. Embossed web (diamonds with a size of 0.54 s + m” over about 34% of its area) It was determined by testing the embossed spot (embossed with a molded spot).

This test was conducted using the gauge length, that is, the gap between the jaws, which was approximately 0.0 as close as possible to o. This was done using a length of 0.09 cm+. The results are shown in Figure 3A. stress in ordinate dy ne/cwt” x 10’ and the apparent strain in % is plotted on the horizontal axis (the stress is plotted in psi x 10" on the right ordinate) did). Young's modulus is 4.47X10' dyne/cm" and breaking stress is 4. ．． 99 x 10' dyne/cm", and the area under the toughening curve) is 2 ．． 69 By using small gaps, the measurements are averaged over the individual fibers. Reflected in the value based on value, and the effect of embossing was avoided. The samples tested were 2 The width was 0-, and the crosshead speed was 20 mm/min.

For comparison purposes, the same polypropylene resin, the same equipment, but for stretching A microfiber-based microfiber similar to this example, made without passing through the chamber. We conducted several tests. These comparison fibers are 3.64 x 12.73 miku lon diameter and had an average diameter of 6.65 microns. response car The strain curve is shown in Figure 3B. Young's modulus is 1.26X10' dyne/cm" The breaking stress is 1.94X10' dyne/cm", and the toughness is 8 ．． 30X10"erg/cs+" The microfiber produced is more durable than the microfiber made by conventional methods. It can be seen that the properties of these materials are 250-300% higher .

WAXS (wide angle X-ray scattering) photographs were made and Figures 4A (fiber of the invention) and 4B (comparative Fiber) For example, the photograph may be placed in the fiber stream exiting the drawing chamber. by collecting the bundle of fibers onto a rotating mandrel or by collecting a collection web. The fibers are cut to a certain length, and then the cut pieces of a certain length are made into bundles. The resulting fiber bundle is shown in the uppermost image).

The crystal orientation of the drawn microfibers is determined by the presence of rings and their rings in Figure 4A. easily revealed by the interference of

The crystal axial orientation function (orientation along the axis of the fiber) is also relevant for the fibers of the present invention. Definitely Alexander, L, E, + X-HaractionMet hods in F’ol yxer 5science, Chapter 4, R, E, Xr ieger Publishing Co., New York, 1979. (For details, see page 241, formula 4-21), It was found that the value was 0.65. This value is the same for conventional melt-blown fibers. It will be very low, at least close to O. A value of 0.5 is a meaningful crystal showing the presence of orientation, and preferred fibers of the invention exhibit values of 0.85 or higher. Ta.

Example 2 Stretched nylon 7 microfibers were made using equipment substantially similar to Example 1. However, the main portion of the drawing chamber was 48 inches (122 cm) long.

This melt-blowing die has a circular smooth surface orifice with a length to diameter ratio of 5:1 ( 25/inch). The die temperature is 270'C, and the first air temperature and pressure are are respectively 270°C and 15PSl (104kPa) and 0.020 inch. C0.05ctm) gap + y gap width), and polymer feeding speed is 0.51b/h r/inch (89g/hr/cs+). For drawing fibers 70 Psi (4 Extruded fibers using a pressure of 83 kPa) and an air temperature of approximately 25 °C. - was extended. The randomization portion of the stretching chamber is 24 inches long. The fiber exited at a speed of approximately 6250 m/min. .

Scanning electron micrographs (SEM) of representative samples range from 1.8 to 9.52 microns. The calculated average fiber diameter was 5.1 microns.

For comparison, an unstretched nylon 6 web was prepared without using a stretching chamber, and , 315, which was selected to make a fiber with approximately the same diameter as the drawn fiber of the present invention. made at a higher Gui temperature of °C (higher Gui temperature reduces the viscosity of the extruded material and this This tends to result in fabricated fibers that are of small diameter; The fibers have a larger diameter than conventionally produced melt-blown fibers as described above. can approach the size of the fibers of the present invention, which tend to be narrower).

The fiber diameter distribution was measured from 0.3 to 10.5 microns, with a 3.1 micron The calculated average fiber diameter was

The tensile strength of the prepared fibers was measured as described in Example I and the obtained The stress curves of the strain curves are shown in Figures 5A (inventive fiber) and 5B (comparative unstretched fiber). (bars), the units of the vertical axis are bonds/inch and the horizontal axis is %.

Figure 6 shows a representative web (6A) of the invention made as described above and a comparative non-stretched web. This is a 32M photograph of the fiber diameter (6B), which further explains the differences in fiber diameter. Illustrate. As you can see, this comparison web contains very small diameter fibers. including, obviously, a large This is the result of turbulence. In the process of the present invention, at the exit of the die This results in a more homogeneous airflow, and this produces fibers with a more uniform diameter. clearly contributes to

FIG. 7 shows the WAX for the fiber of the present invention (7A) and the comparative fiber (7B). S photo is shown.

Example 3 Polyethylene terephthalate 1- (East+wan Ches+1cal C o, East-wsan A150) drawn microfibers from It was produced using the equipment and conditions of Example 2, except that the Gui temperature was 315°C, and The first air pressure and temperature were 20 PSI (138 kPa) and 315 kPa, respectively. It was set to °C. The fiber exit speed was approximately 6000 m/min. F measured with SE- The distribution of iber diameter is 3.18 to 7.73 microns, with an average value of 4.94 microns. It was.

Same resin and same conditions, but slightly higher Gui temperature (335°C) and for stretching Unstretched microfibers were made for comparative example purposes without a chamber. child The diameter of the fibers is 0.91 to 8.8 microns, with an average value of 3°81 microns. It was Ron.

Figure 8 -AXS for oriented (Figure 8A) and comparative non-oriented fibers (Figure 8B) This is a pattern photo. High crystal orientation of drawn microfibers is evident .

Example 4-6 The stretched microfibers were The melt flow index (MFI) of Example 5) and 800 to 1000 (Example 6) was It was made from three types of polypropylene. Using the apparatus of Example 2, the Gui temperature is 185°C, and the first air pressure and temperature are 200°C and 20°C, respectively. PSI (138kPa), the exit speed of the fiber was 9028m/ Microfibers of 400-600MFI were prepared by SEH. , ranging in diameter from 3.8 to 6.7 microns, with an average diameter of 4.9 microns. This was recognized.

The tensile strength of the produced microfibers of 800 to 100,100 O is Inst measured using a ron tester and the stress strain curve shown in Figure 9A (Factor of the invention). 9B (comparative non-stretched fiber).

For comparison purposes, unstretched microfibers were treated with the same resin and under the same conditions, but Made without high Gooey temperature and without drawing fibers.

The fabricated 400-600 MFI fibers ranged in diameter from 4.55 to 10 microns. The average value was 6.86 microns.

Example 7 Using the apparatus of Example 2, polyethylene terephthalate (melting point 251'C, 65~ (crystallizes at 70°C), the drawn microfibers are heated at 325'C (7) The temperature of the first air is 325℃ and 20PSI (138kPa), respectively. pressure and lb/hr/inch (178g/hr/cm) poly I made it with the amount of preparation. The exit velocity of the fiber was 4428 m/min. The fibers ranged in diameter from 2.86 to 9.05 microns, with an average diameter of 7.9 microns. It was Ron.

Comparative microfibers were also produced using the same resin and the same operating conditions, but at higher temperatures. Made without temperature and stretching chamber. These fibers are 3.18-14. 55 microns in diameter and had an average diameter of 8.3 microns.

Examples 8-12 A web was produced using the apparatus of Example 2, except that the randomization section of the drawing chamber was The length should be as wide as shown in Figure 1, and the length should be 20 inches (51c+w). did. Only the two wide walls of the chamber are flared, and the corners of the flared The degree θ was set to 6°. Conditions were as described in Table I below. Furthermore, the same polymer Comparative webs were made from the material except that the fibers were spread across the drawing chamber. The conditions for the comparison web are also shown in Table ■ (symbol “C ), further examples (11X and 12x) similar to those described in Examples 11 and 12. However, the width of the hem of the stretching chamber 24 was randomized. The section was 24 inches (61 cm) long, and the web had a star pattern (center point and 6 linear sections radiating from a point), where 1 part of the area of this web Emboss the web to cover 5%, and then put the web under an embossing roller for 1 day. The embossing temperature and 20 PSr (138 kPa) shown in Table ■ were passed through at a speed of Both the inventive web prepared using pressure and the comparative web had a gripping tensile strength. Machine direction (MO), i.e., collector rotation, for strength and strip tensile strength and the transverse or transverse direction (TO) according to ASTM D 1117 and and the procedure described in D1682), and the results are shown in Tables ■ and ■. Ndorf tear strength (STM D 1424) was also measured for some samples. and report in Table ■.

Theft - Ichinoseki average tear force MO (g) 688 1.64 1916 680 880 101016TO (8321602084124821601884 questions (N) 6.74 1.6 0 18.7B 6.66 8.62 9.95TD(N) 8.15 1.5 ? 20.42 12.23 21.16 18.46 Weight base g/m” 55 54 51 52 52 49 Average tear per weight hese unit Power Question (N/g/Peng”) 0.122 0.03 0.37 0.13 0.166 0.203TD (N/g/Kabura”) 0.148 0.029 0.400 0 ．． 23 0.407 0.377 Example 13 As an illustration of a useful insulating web of the present invention, 65% by weight made according to Example 1 oriented melt-blown polypropylene microfiber (detailed conditions below) (see Table V) and 35% by weight 6 denier crimp 11/4 ( 3.2 cm) A wool comprising polyethylene terephthalate staple fibers. I made a web. This web is crimped with a lickerin roll. Pick up a stable fiber (using the apparatus taught in U.S. Pat. No. 4,118,531) ), then this picked staple fiber is drawn into a melt-blown fiber - into the stream of - as it exits the drawing chamber. I made it. The diameter of this microfiber was measured using SEM, and The average diameter was 5.5 microns. This website The bottle has a very flexible feel and cannot be supported on an upright support, e.g. a bottle. It hung easily when closed.

For comparison, the same crimped stem “luterephthalate phino” and the present invention Microphytsummer on the web of Polypropylene microfibers (without s) are passed through a stretching chamber. (13C) consisting of the following.

The insulation value was determined for two types of web before and after washing 10 times in the 11aytag clothes washing machine. The measured pupils and the results are shown in Table ■.

Table-y Heaven 1119- Die temperature (C) 200 310 310 Temperature (C) 200 310 3 10 orientation chamber Pressure (PSI) 70 70 70 (kPa) 483 483 483 Temperature ("C) Full area Surroundings Dark area Polymer extrusion speed Examples 14-15 80% by weight polysilicine made in the apparatus described in Example 2 using the conditions described in Table ■. Lohexane terephthalate (crystal melting point 295° (; EastmanChem ical Corp, 3879) and Example 13 2011 into a stream of melt-blown drawn fibers by the method described in Contains 6 denier polyethylene terephthalate crimped stable fiber of A heat insulating web of the present invention was produced. It has the weight listed in the table ■ below. Two types of webs with excellent drapability and soft touch were produced. Two types of ware The thermal insulation properties of the tubes are also shown in Table ■.

[■ Sue Tomoko's first +-14th trial Equipment (g/m”) 133 106 150 Thickness (CM) 0.73 0 ．． 71 Adiabatic efficiency (clo) 1.31 1.59 (clo-m’/kg) 9.8 + 5.0 13.9”’ – After 10 washes % insulation efficiency retained 103.1 92.2 99.6 Thickness (% retention rate) 9 7.3 98.6 Example 16 Stretched melt-blown polycyclohexane terephthalate microfiber at 65' bar (East@an 3879) and 35% by weight 6 denier polyethylene Making the insulating web of the present invention comprising phthalate crimped staple fibers It was. The conditions for producing drawn melt-blown microfibers are shown in Table ＼・′, The measured characteristics were as shown in Table ■. This web has excellent drapability and It was soft and soft to the touch.

Examples 17 and 18 A first web (Example 17) of the present invention was produced according to the example, but as shown in FIG. Two dies as shown were utilized. For die IOA, die temperature is 200° C, and the temperature and pressure of the first air are 200°C and 15PSI (10 3kPa), and the air temperature and pressure in the drawing chamber were set at ambient temperature, respectively. The temperature was set at 70 PSI (483 kPa). The polymer charging speed is 0.51 b/hr/inch (89g/hr/c+w). The fibers leaving the fiber are separated from the non-stretched melt-blown polypropylene fibers made in die 10b. Composite with pyrene fiber. For die IOB, die temperature is 270°C The pressure and temperature of the first air are each 30 PSI (206 kPa ) and 270°C. The polymer charging rate was 0.51 b/hr/inch (8 9g/hr/cm).

As a comparison, another inventive web (Example 1B) was made by the method of Example 4 and It comprises only drawn melt-blown fibers. Both Examples 17 and 18, Using a temperature of 275 °C (135 °C) and a pressure of 20 PSI (138 kPa) spot pattern (approximately 0.54 iv" area) at a speed of 8 ft/min. Monde type spots (accounting for about 34% of the total area of the web) were embossed.

Both the embossed webs of Examples 17 and 18 were tested for tensile strength, versus stress. Measure in the device direction, HP, collector movement direction, and lateral direction using a tron tester. and report the results in Table ■ below.

People-■ Moon age 1-17 Ml) CD stress (PSI) 160024002700295016002350265028 50 (kPa) 1100816512185762029611008161 681823219'608 Distortion% 6 12 18 24 6 12 1B 24 Grudge 6 MD CD stress (Psi) 2900400047f) O45005507509251075 (kPa) 199522752032336310233784516063 647396 Strain% 6 12 18 24 6 12 18 24 Example 19 Using the apparatus shown in Figure 2 with the second chamber removed, polypropylene resin Uimont Ultra-fine ultra-micron fibers are blown from Pf422), extrusion temperature is 435° F (224°C), and the die temperature was 430°F (221°C). . The extruder was operated with a 5RP gate with a purge block (3/4 inch diameter, model N o, D-31-T, C, W, Brabender Instrument s of Hac-kensack, New York), Igm+/Orif Excess polymer was purged to bring the polymer flow rate closer to less than . This die has 98 orifices, each approximately 0.005 inch (12 5 μm) orifice size and 0.22 inch (0.57 cm) orifice size. It was fist length. The first air pressure is 30PSI (206kPa), and The gap width was set to 0.01 inch (0.025 cm). This polymer The second stretching air blown into the stretching chamber was 70PSI (483k Pa), the air gear knob width is 0.03 inch, and the ambient temperature And so. The Coanda surface had a radius of 1/8 inch (0.32 cm).

This chamber has an internal height of 1.0 inches (2,54 cm) and a 4 inch (10,16 cm) internal height. cm), and had an overall length of 20 inches (including the flared exit section). .

The formed fibers had an average fiber diameter of 0.6 μm, and the fibers were D 52% was in the range of 0.6 to 0.75 μm. Approximately 85% of fibers are 0 ．． It was in the range of 45 to 0.75 μm. (The fiber size and distribution are Based on the scanning electron micrograph of Bausch & Lomb, Determined by analysis with the sicon™ image analysis system. somewhat of fiber roving (approximately 3%) was observed.

Example 20 This example again uses the apparatus and polymer of Example 19 without using the Hata chamber 38. Using. In this embodiment, the chamber 37 has side walls made of porous glass. and this is a 15 1/2 inch long channel excluding the flared exit portion. It had a bar. The air that cuts through the chamber 37 passes through various angles. It was also adjustable to allow it to be conveyed to the Coanda surface at a degree. this The Coanda surface has a radius of 1 inch (2,54cs+) and a 45 degree air It had an exit angle. The extruder temperature ranges from 190 to 25 from inlet to outlet. 5°C and rotated at 4 revolutions per minute (0.75 inch, 1. 70-mm screw diameter) to keep the polymer flow rate low and the polymer flow rate in the die A purge block was also used here to prevent excessive residence time. The polymer flow rate is 260gm/hr (2.6g/min/orifice), die temperature 186° C and each 0.005 inch (0,013 cm) orifice It had an orifice with an is.

The pressure of the first air is 10PSI (70kPa), and the width of the air gap is It was set to 0.005 inch (0,013 cm). Cooling air through porous glass walls The pressure was 10 PSI (70 kPa). Collector is 2 from die I placed it at 2 inches (56cm). Under a microscope, fibers have an average diameter of 1 μm. It was recognized that the

Examples 21-34 The equipment and polymer of Example 19 above were used.

Process conditions are listed in Table ■ below.

table - person Tan XL Engineering L Engineering 1-1 Red Engineering 11ffi Dan U 12 Engineering, 21 240 250 250 230 25 50 Bo 2 18023 240 25 0 250 230 25 25 so 10 18 (13024025025 02302535521,80T, - Extruder outlet temperature (°C) T2-Purge block temperature (C) T, - temperature of die (°C) T a + Tut - temperature of air stream, i.e. for first air and first stretching Temperature of each air (°C) PmlPmZ - Pressure of the above air stream ( Psi) Fl - Polymer flow rate is approximately 2.5 gm/h for Examples 31-33 r/orifice.

R-Extruder IIPM T, - melting point (°C) Next, the fiber size (micrometer) distribution is determined from the results listed in Table X below. Decided.

21 2.7 2.8 0.6 1.5-3.5 1522 4.8 4.6 2.4 0.1-8.1 1623 2.2 2.1 1.4 0.5-4.5 2124 2.7 2.7 0.6 2.1-3.7 1325 1.7 1 ．． 7 0.3 1.4-2.2 1526 2.0 2.0 0.5 1.5- 3.5 2227 2.6 2.5 0.4 1.6-3.4 1928 2. 5 2.3 1.0 1.0-4.0 2829 2.4 2.4 0.6 1 ．． 0-4.0 2030 2.5 2.6 0.4 1.7-3.8 2031 0.93 0.82 0.38 0.6-1.6 3732 0.80 0. 81 0.25 0.3-1.2 10133 0.90 0.85 0.07 0.78-0.92 100 In Table X, 90% range means 90% or more of the range. This is the size range in which fibers are recognized, and Ct is the number of fibers measured. , and St and Dev represent the standard deviation. Generally narrower size The distribution was observed at slower polymer flow rates. Examples 22 and 23 used a high extruder speed. and a significantly wider fiber diameter range than Examples 21 and 24. The area is shown.

The last three examples (31-33) in Table X have smaller average diameters than the other examples. It had This is a relatively low first air pressure and drawing chamber orifice. It is believed that this occurs in combination with relatively high air pressure from

Implementation f! A33 is an extremely small average diameter fiber with a very narrow fiber diameter range. - brought about. The scanning electron micrograph of the fiber of Example 33 in FIG. Indicates uniformity of fiber size ('5.0kx　The small line segment under J is 1 mile. chromator).

Example 34 In this example, the same equipment and polymer as in Example 20 were used, except that A 2 chamber 38 (ie, that used in Example 19) was used. extruder and A metering pump ratio was used to control the purge block. This extruder The outlet temperature is 240°C, and the purge block and die are 250°C. Ta. Is this extruder 2RP? It was operated at l.

The operation of the purge block was controlled by three precision pumps (pump 1, “Zenit J Pump, Model No., HPB-4647-0,297; Pump 2 and 3, 'ZenitJ pump, model No., HPB-4647-〇, 160 ;Powell Equip+went Company,Minneapo lis, Minnesota).

Pump 1 and Pump 2 are equipped with precision, adjustable, constant speed motors (model number Bar 5RP56 to AA62+ Boston, Massachusetts It was driven by Boston Gear Company. These pons The pump is connected to a full-time gear drive, which allows pump 1 to match the speed of pump 2. Drives at 5x. Pump 3 is driven by a separate precision speed motor of the same type. I let it happen. These pumps split a fast stream of resin into two streams. divide. The larger polymer stream from pump 3 is removed (purged) from this system. ). A smaller stream from Polymer 2 was retained.

The smaller stream was passed through a small glass pipe with a mesh of 240 holes/in. The filter layer of the lens is free from any foreign particles larger than 1 micron (1 μm). The material is then passed through something that can remove the material, which is then conveyed to a die, which then passes through an orifice ( 0.012 inch, 0.03 cm).

The temperature (21O°C) and pressure (0 , 01 inch air gear knob to supply die at 5 PSI) and capacity/unit time. did.

The flow rate of the polymer through the die prior to the actual formation and recovery of the fibers of the present invention. by collecting a sample of the resin stream that emerges just beyond the die. This is done by placing a small weighed piece of mesh/screen at that point. By putting. After 5 minutes, reweigh the screen and record the weight of resin recovered. The extrusion speed in grams/hole/min was calculated.

After making this measurement, the resin stream is routed through two separate chambers. Ta.

The first drawing air stream melts over the first chamber - however. Used to convey a stream of cooled resin.

The pressure of the stretching air was 10PSI (70kPa), and the air gap was 0. Air was pumped through the porous sidewalls of the chamber, measuring 0.3 inches (0.076 cm). It was also introduced at 5 PSI (35 kPa).

These fibers are then subjected to a second draw when they have cooled substantially or completely. The stretching chamber 38 has a width of 0.03 inch (0.03 inch). 60PSI (412kPa) stretching air with air gear knob of 076c+w) Chimney introduced through opening with earth stream and 5 PST (35kPa) It has an entangling air stream near the chamber exit. Pump 1 ( 31) to Figure 2 is operated at 1730 RPM and pump 2 (32 in Figure 2A) is driven at a speed of 115, and pump 3 (33 in Figure 2A) is operated at a steady state. It was operated at approximately 90 ORPM. Polymer feed rate is Igm/hr/original It was a fiss. The fibers formed have an average diameter of 1.1 μm, and all fibers The fiber diameter (6 pieces measured) was in the range of 0.07 to 1.52 μm.

For comparison, this same polymer was added to either chamber (37 to Figure 2 or 38) All conditions for the remaining steps of this melt blowing process are the same. However, the first air pressure was increased to 10PSI (70kPa) 0 times. The collected fibers had an average fiber diameter of 1.41 μm, with a standard of 0.37 μm. It was a standard deviation. All fibers were in the range 0.5-2.1 μm.

For further comparison, a higher polymer blowing rate (89 g+m/hr/orig. See Example 1, which utilizes the This condition applies to stretched and non-stretched melts. This resulted in a wider range of fiber diameters for both blown fibers.

゛ Example 35 This example was carried out according to the procedures and equipment of Example 34. Polymer is polyethylene Dow Aspun (quotient 1) 6806+ Dow Chemical Co, + Mid-1 and Ml). The extruder is 311P ? The outlet temperature was approximately 200'C. Gear pump 1 is 1616R Gear pump 3 was operated at 10171'lPM. of polymer The feed rate was approximately 1.0 gm/hr/orifice. First air temperature and melting temperature The temperature was 162°C in both cases. The air pressure of the first air is 6 PSI (32kP a). The stretching air in the chamber 37 is 0.01 inch (0.02 50 PSI (345 kPa) with a gap width of 5 cm), and The cooling air was set at 10 PSI (70 kPa). 2nd chamber is 50PS Stretching air at l (345kPa) and air at l0PSI (70kPa) It had an airstream for tangling. Average fiber diameter is 1.31 μm and the standard deviation was 0.49 μm (12 samples). ibers range in size from 0.76 to 2.94 micrometers, with 94% being 0. ．． It was 76-2.0 μm. This goo has 56 orifices, each with was 0.012 inch (0.03 cm).

Example 36 Polymer feed rate of Example 35 was 0.992 g/hr/orifice. (1670.922 and 3 gear pump 31, gear pump 33 and 3 respectively) and extruder RPM) as in Example 34. The first air (170℃) is 0 ．． l0PSI (70k Pa). The melting temperature of extrusion from a 200"C die was 140°C (extrusion The exit temperature of the outlet and the block temperature are approximately 170'C). Formed unstretched fiber had an average fiber diameter of 4.5 μm with a standard deviation of 1.8 μm. 93 % of fibers were found in the 2-8 μm range (47 fibers sampled).

In comparison, the polyethylene fiber of Example 3 has approximately the same properties when unstretched. It had the same fiber size distribution, but compared to Example 35, it had the same fiber size distribution. The fiber size distribution was wider.

Examples 37 and 38 These examples were performed according to the procedures of the previous examples. The polymer used is (RASF KR-4405), and for non-stretched and stretched examples, 0.005 inch (0.013 cm) and 0.012 inch (0.03 cm), respectively. ) was utilized. 2 extruders each and 20 RPM with outlet temperatures of 310 and 300"C, respectively. A and feedblock temperatures are 280°C and 270°C, respectively. and 275°C and 270°C. Gear pumps 3I and 33 are respectively It was operated at 1300 and 1330 RPM. The melting temperature is 231 and 23 respectively 4°C, and the first air temperature was 242 and 249°C, respectively. fruit Example 37 was not stretched, but with an air gap of 0.01 inch (0,025 C■). Only primary air of 7 ft'/min (0.2 m'/min) was used. The resulting fa The fibers had an average diameter of 1.4 μm and a standard deviation of 1.0. of fiber 95% of them (62 measured) were fibers in the range of 0.0 to 3.0 μm. It was. For comparison, a taller polymer yielding a wider range of fiber diameters See 1M Example 2 regarding flow rate.

Example 38 is 3.5 ft'/min (0,01-7 cm (0,025 cm) 0) Stretching was carried out using a primary air pressure of 10 PSI or 70 kPa) in an air gear tube.

The 1,000th yanbar 37 uses 20 PSI (140 kPa) stretching air and 5 P si (35 kPa) of side wall air. The second stretching chamber is 40 PSI (277kPa) of air and 5 Psi (35kPa) of air It had air for gluing.

The resulting fibers had an average diameter of 1.9 μm with a standard deviation of 0.66 μm. It was. 91.6% of the fibers (24 fibers measured) are 1.0 to 3.0 μm It had a diameter within the range of .

The above examples are for illustrative purposes only. Various improvements and modifications of the present invention are within the scope of the present invention. Without departing from this scope, the invention is not limited to what has been described for illustrative purposes. It won't happen.

FIG, 3A PIC+, 3B F+c, -5 snake Fic, 6B FIG. 7A To Fl, 7B Etc, BR FIG, 9B Fiber diameter international search report RorT/1leO5/111701 Continuation of front page St Paul, Bost Office Pock St Paul, Post Office Bo x33427 (72) Inventor Mayer, Daniel Yi.

United States, Minnesota 55133-3427゜St. Ball, Boston Fis Pock, United States, Minnesota 55133-3427゜St. Post Office Box 33427

Claims (16)

[Claims] 1. comprising drawn, substantially continuous melt-blown fibers, herein referred to as The average fiber diameter of these fibers is about 10 micrometers or less, and At least 90% of the fibers are within 3 micrometers of this average fiber diameter. A non-woven fabric having substantially no shot, belonging to the range of tars. 2. the average fiber diameter is about 5 micrometers or less; At least 90% of the backs of the fibers are within 2 micrometers of this average diameter. 2. The nonwoven fabric according to claim 1, belonging to the. 3. 3. The average fiber thickness of claim 2 is 2 micrometers or less. Non-woven fabric. 4. at least 90% of the fibers are within about 1 micrometer or less; The nonwoven fabric according to claim 3. 5. further comprising crimped stable fibers oriented in the melt-blown fibers. The nonwoven fabric according to claim 1, comprising: 6. the melt-blown fiber has a crystallographic orientation function of at least 0.65; The nonwoven fabric according to claim 1. 7. wherein the melt-blown fiber has a crystallographic orientation function of at least 0.8. The nonwoven fabric according to claim 1. 8. Minimum machine direction tensile strength of 1.5 newtons/gum/square meter or more , to weight, and is greater than or equal to 0.1 newton/gram/square meter. Contains a bonded web with a minimum machine direction Elmendorf tear strength, to weight ratio The nonwoven fabric according to claim 1, comprising: 9. The web of fibers occupies 5-40% of the area of the fabric. Claims joined by heat stamping at intermittent individual joining areas Item 8. The nonwoven fabric according to item 8. 10. Minimum equipment direction ■ tensile strength of 2.5 newtons/grams/square meter or more and has a ratio of weight to weight of 0.25 newtons/grams/square meter or less. A bonded web with a minimum device direction Elmendorf tear strength, vs. weight ratio of 2. The nonwoven fabric of claim 1, comprising: 11. The molten fiber molding polymer material is heated through an orifice in a die. Manufacture of microfibers by extrusion into a velocity gas stream The fiber is transferred from the die orifice to a melt-blown attenuation hop. airflow into a long tubular chamber with substantially parallel side walls and then introduce these fibers into this chamber and this chamber. These fibers are sufficient to keep them under tension with this die. sufficient for the fiber to exit the sidewall area of this chamber without noticeable vibration. It is characterized by passing through this chamber together with the air being blown in at a certain speed. How to do it. 12. The tubular chamber is a flat box-like chamber with a widened bottom and an exit portion. 12. The method of claim 11. 13. Air is introduced into the tubular chamber and into the Coanda curved surface at the entrance of the chamber. 12. The method according to claim 11, wherein the method is introduced over a period of time. 14. Claim 1, wherein the orifice in the die is a circular smooth surface orifice. The method described in 1. 15. The fiber is subjected to vibrational movement before it exits the side wall of the chamber. This fiber is placed with air to keep it under tension so that it is stretched without , through a second elongated chamber having substantially parallel side walls. The method described in. 16. the fiber is drawn primarily within the second elongated chamber; and wherein the fibers are connected to the fibers in the fibers, the sidewalls of which are substantially flared. 16. The method according to claim 15, wherein the two chambers are subjected to vibrational movement at the outlet section.