JPS62191436A - Method and apparatus for manufacturing mineral fiber with non-round section - 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 <Industrial Application Field> The present invention relates to a method and apparatus for producing mineral fibers used as textile materials, reinforcing materials, building materials, heat insulating materials, and the like. In the context of the present invention, mineral fibers mean fibers of glass, rock, slag or basalt, and the invention particularly relates to mineral fibers and glass fibers with a non-circular cross section.

<Prior art> The technology of producing glass wool using centrifugal force is well known. Generally, molten glass is fed into a spinner that rotates at high speed. The spinner has a peripheral wall with a plurality of orifices. The molten glass that passes through the orifice in the peripheral wall due to centrifugal force becomes a small-diameter molten glass flow. An annular blower is provided on the outer periphery of the spinner to deflect the fiber downward, and in some cases, a secondary diameter reduction process is performed to form a smaller diameter fiber.

The viscosity of the flow of molten glass is sufficiently low at the time it is discharged from the orifice, so regardless of the cross-sectional shape of the flow of molten glass discharged from the orifice, its surface tension creates a roughly circular cross-section. It comes to have. Additionally, if the centrifugal fiber manufacturing equipment is equipped with an annular burner or other hot gas source for secondary fiber reduction, these hot gases can keep the glass in a low viscosity state. As a result, the cross section of the fiber becomes approximately circular.

It is also well known to produce continuous glass fiber from textile sections by mechanically drawing a stream of molten glass from an orifice in the bottom wall of a bushing or feeder. Again, even if the molten glass flow has a non-circular cross-section, surface tension will eventually cause the molten glass flow to have a circular cross-section before it is cooled and hardened into glass fibers. Therefore, as in the case of glass wool production, it has not been possible to produce continuous 1iJA@ with a markedly non-circular cross section using different diameter orifices provided in the bushing.

In both methods using centrifugal spinners and continuous fiber methods, there has been a need to produce fibers with significantly non-circular cross-sections. The use of such non-circular cross-section fibers can significantly increase tensile and shear strength when reinforcing resin matrices. Furthermore, even when fibers with a non-circular cross section are used as a heat insulating material, glass l! The surface area per unit volume of the fiber is increased, and its thermal conductivity can be reduced.

The degree of non-circularity of the cross-section of a mineral fiber can be expressed by the mod ratio, which is the diameter of the smallest circle that can be covered by the cross-section of the fiber to the diameter of the largest circle that can be covered by the cross-section of the fiber. expressed as a ratio. In this specification, if the mod ratio is less than 1.2, the cross section of the fiber is considered to be circular, and if the mod ratio is 1.2 or more, it is considered to have a non-circular cross section. .

In the method of manufacturing a glass fiber with a non-circular cross section proposed in U.S. Pat. No. 3,063,094, the molten glass is It consists of applying mechanical perturbation to the flow. According to this US patent, in order to form fibers with a non-circular cross section, the flow of molten glass, which initially has a conical shape with a circular cross section, is continuously reduced by reducing its diameter. When forming fibers, by deforming the region where the viscosity has become sufficiently high due to rapid cooling,
A similar effect remains on the cross section of the fibers that have been reduced in diameter and solidified. This patent publication also teaches a method of bringing a heat sink into direct contact with a flow of molten glass. This results in
The viscosity of the molten glass increases, making it possible to maintain the non-circular cross-section of the agitated glass flow even more favorably.

In the technical field of manufacturing organic fibers, a quenching method is generally used in which a molten organic material is passed through orifices of different diameters to solidify it. However, the process is carried out under conditions that are practically very different from those for producing mineral fibers.

The production of organic VIa fibers with non-circular cross sections can be easily carried out by pressurizing the bushing, but
Pressurizing bushings that store molten glass creates significant operational problems.

Generally, there is a temperature of 815°C (1°50°C) between glass and organic material.
There is a difference in melting point of more than 0' F). Mineral materials of this invention have liquefaction temperatures of 1,200" F. or higher, whereas organic materials soften or decompose at much lower temperatures.

Differences in physical properties between glass and the materials that make up organic fibers can be understood by comparing their viscosity to surface tension ratios.

The ratio of viscosity to surface tension (poise/(dyne/cm)) of the polymer is about 25-5. OOO, whereas in the case of glass this ratio ranges from 0°1 to 25, generally from 0.25 to 15, and in many cases from 0.4 to 10. within the range of The viscosity of molten glass when forming fibers is generally about 300 poise, whereas the viscosity of molten organic materials ranges from i,ooo to 3,000 poise. In addition, the surface tension of glass (250 to 3
00 dynes/cm) is the surface tension of an organic material (30
dynes/cm), which differs by one order of magnitude. In this way, due to the properties of glass having low viscosity and high surface tension, it is possible to prevent the tendency of the cross-sectional shape of glass fibers having different diameter cross sections to become circular, compared to the case of organic material 1. It can be said that it is 100 times more difficult.

<Problems to be Solved by the Invention> Various attempts have been made to produce mineral fibers with non-circular cross-sections, but they have non-circular cross-sections due to non-circular orifices. No method or apparatus for producing such fibers has been commercially successful.

<Means for Solving the Problems> According to the present invention, mineral fibers such as glass fibers are discharged as a flow of molten mineral material from a non-circular orifice, and mineral fibers having a non-circular cross section are added to the flow as mineral fibers having a non-circular cross section. It can be made to have a non-circular cross section by applying a cooling process that can be forced quickly enough to harden. This cooling process, which may be forced, causes the molten mineral material to harden into fibers with a non-circular cross-section before becoming circular in cross-section due to its surface tension. By using such a quenching process, according to the invention it is possible to produce mineral fibers with a higher mod ratio than was possible with methods based on the prior art. The present invention is applicable to both a method using a centrifugal spinner and a continuous fiber manufacturing method.

A preferred method for rapidly cooling a stream of molten mineral material is to impinge a stream of scum such as relatively low humidity (e.g. room temperature) air against the stream of molten mineral material; It can also be carried out by applying a stream of water, spraying water, using a liquid bath, ultrasonic waves, fin shield, etc.

Generally a flow of molten mineral material with a high mod ratio will have a larger surface area (perimeter) and therefore a smaller rnod
will have more favorable heat transfer properties (and cooling rates) for flows of mineral materials with the same ratio. When using a cooling gas, the temperature and flow rate of the cooling gas not only affect the cooling rate, but also the speed of the flow of molten mineral material and the flow of molten mineral material passing through the flow of cooling gas. The time required for cooling, or the distance that the stream of molten mineral material travels while hardening into fibers, also has a significant effect on the cooling rate.

The method for producing mineral fibers according to the present invention involves the following: lubrication force (positive pressure in the continuous mineral fiber production method or positive pressure in the centrifugal spinner method), centrifugal force in the centrifugal spinner method, molten mineral material The temperature and viscosity of the molten mineral material, the depth of the non-circular orifice, the surface tension of the molten mineral material, the rate of movement of the molten mineral material stream, and the cooling rate of the molten mineral material stream.

The positive pressure applied to the molten glass, the inertial force on the molten mineral material projected from the centrifugal spinner, the mechanical tensile force in continuous fiber manufacturing methods, etc., affect the final m of the mineral fibers.
Affects od ratio. Since surface tension acts to circularize the cross-sectional shape of the flow of molten mineral material before it reaches the flow of cooling gas,
Also, since the cooling gas flow will be some distance from the lower end of the non-circular orifice, the time required for the flow of molten mineral material to reach the region of the cooling gas flow is important.

According to the present invention, the process includes: discharging molten mineral material from a non-circular orifice to form a flow of molten mineral material having a non-circular cross-section; , so as to cure as a mineral fiber with a non-circular cross section similar to the shape of the Δrefice,
quenching the flow of molten mineral material. A plurality of such orifices can be provided in the wall of a container containing molten mineral material. This container may consist of a centrifugal spinner or a feeder, for example.

According to one aspect of the invention, the quenching step is carried out by impinging the flow of molten mineral fibers with a cooling fluid at a flow rate and trajectory such that the flow does not have a circular cross section.

In accordance with the invention, it is further provided in the range of about 1.2 to 50, preferably about 1.3 to 50, for storing molten mineral material and discharging said molten mineral material in one or more streams.
a bushing having a wall with an orifice having a mod ratio in the range of about 25, most preferably in the range of about 1.7 to 10, and directing the flow of said molten mineral material before it has a circular cross section; and means for rapidly cooling the flow of the molten mineral material, wherein the mineral fiber is cured as a mineral fiber having a non-circular cross section similar to the shape of the orifice. be done. The orifice may have a shape having three regions projecting radially at equal intervals in the circumferential direction.

<Embodiments> Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Although this embodiment relates to a method and apparatus for manufacturing glass fiber, the method and apparatus based on the present invention can also be used to manufacture mineral fibers manufactured from mineral materials such as rock, slag, or basalt. Needless to say, it can equally be applied to other purposes.

As shown in FIG. 1, a stream 10 of molten glass exits the orifice-containing bottom wall 12 of a feeder or bushing 14 and is blown into fibers by any suitable means, such as the mechanical action of a winder 18. It is drawn out as 16. Collection shoes 20, size applicators 22, etc. can be used in a manner known per se. Bushing 14
stores molten glass 24 from which a stream of molten glass is drawn. As shown, an air nozzle 26 for quenching the stream of molten glass is positioned to direct air toward the stream of molten glass exiting the bottom wall 12 of the bushing 14.

This air flow is similar to the initial non-circular flow of molten glass.
The molten glass stream is cooled rapidly enough to solidify as a glass fiber while retaining the 1'i plane. Other suitable cooling fluids, such as carbon dioxide, nitrogen, steam, water, etc., can also be used to force the cooling of the molten glass stream.

As shown in FIGS. 2 and 3, orifices 28 are formed in the bottom wall 12 of the bushing and have portions that project in the radial direction at equal intervals in the circumferential direction. The cross section of the orifice 28 and the fiber produced may have any shape, such as a cross, a star, a shape with five projecting regions, a shape with eight projecting regions, or a square.

In order to qualitatively explain the manufacturing process of a glass fiber with a non-circular cross section, it is useful to consider the time constant τ of the changing process. As a flow of molten glass having a non-circular cross-section is discharged from an orifice having a non-circular cross-section, the surface tension applied to the flow tends to circularize the cross-sectional shape. In response to this surface tension, viscosity attempts to maintain a constant cross-sectional shape of the flow. As the flow of molten glass travels farther from the orifice, the viscous force increases rapidly as the molten glass cools. In order to successfully produce fibers with non-circular cross-sections, the viscous forces (i.e., viscosity) must increase rapidly to be sufficient to counteract the effects of surface tension forces.

This time constant is considered to be expressed by the following equation as a function of the viscosity of the glass, the equivalent diameter of the flow of molten glass, surface tension, etc.

τ=μr/σ This equation can be modified to have a factor of velocity, integrated over the length of the fiber, ie perpendicular distance from the orifice, rather than time. In actual operation, if the time required for the molten glass to solidify, that is, for the viscosity of the molten glass to increase significantly,
The fiber retains its non-circular cross section. However, after a sufficient amount of time has elapsed before the viscosity of the molten glass increases, the cross section of the molten glass flow becomes circular, producing fibers with a circular cross section. Integrating the reciprocal of the time constant over the distance required to achieve 100% diameter reduction yields the ratio of the time required for the viscous force to increase to the time required for the cross section to become circular. This ratio is difficult to measure accurately, but can be estimated by the ratio Z given by the following equation.

Z=(X7.σ./μoreo)*(1/vo)*1/
(MRo-1> However, X75 is the distance (cm) between the point where the diameter of the flow of molten mineral material reduces to 75% and the bushing, and μ
is the initial viscosity (poise), 'eo is the initial effective fiber diameter (ra), σ is the initial surface tension of the molten mineral material (dynes/cm), and Vo is the The initial velocity of the flow of molten mineral material through the orifice (
m/s) and MRo is the initial mod ratio of the flow.

1,/(MRo-1) is a factor representing the mod ratio of the orifice, ie, the desired mod ratio of the flow of molten glass. This equation agrees well with theoretical considerations, as shown in FIG. The curve shown in FIG. 4 represents the reciprocal of the time constant as a function of distance from the bushing. The integral value corresponds to the area under this curve,
The smaller this area is, the less time it takes for the stream of molten glass to solidify, and thus the greater the mod ratio. It has also been found that in order for the cross section of the finally produced fiber to be non-circular, Z must be 2 or less, preferably 1 or less.

The physical force or positive pressure at the orifice affects the degree to which the cross-section of the glass fiber produced is non-circular. This pressure can be created by head pressure of the molten glass, pressurization by feeder gas, or a combination thereof. To produce continuous glass fibers, positive pressures ranging from about 2°800 Pascals (0.4DSiC1) to 690,000 Pascals (100psiq) may be applied. Especially for molten glass materials
, 800 (0,71) sicl) to 34,000 Pascal (5° Opsig).

Although the bushing shown in FIGS. 1-3 was a tipped orifice, the invention is equally applicable to a tipped orifice.

The orifice shown in FIG. 5 has a depth t.

The smaller the orifice depth, the greater the mod ratio for fibers with non-circular cross sections. Preferably, the depth of the orifice is about 0.025 m (0.025 m).
It is preferably within the range of 0.01 inch to 6.4 m (0.250 inch).

Mineral fibers produced according to the present invention generally have a
μm (0,2x10-” inch) ~ 76 μm (30
Although non-circular cross-section fibers can be produced with diameters significantly different from this, non-circular cross-section fibers can also be produced with equivalent diameters in the range of 0x10-5 inches). Preferably, the mineral fibers have a diameter in the B-Y filament range, ie in the range of 2.5 μm (10×10′ inches) to 30 μm (120×10 −5 inches). In particular, the mineral fibers according to the invention are G-T filaments, i.e. 8.9 μm (35xl
Q inch) ~ 2I41μm (95 x 10-5 inch)
Preferably, it has a diameter in the range of .

Figures 6-9 show cross-sections of fibers with four different non-circular cross-sections produced by equipment similar to that shown in Figures 1-3. The cross section of these fibers is shaped like an orifice with three radially outwardly projecting portions.

This manufacturing apparatus is controlled to approximately constant operating conditions except for the flow rate of the cooling fluid. The flow rate of the cooling fluid is changed for each type of fiber. The rate at which a stream of molten glass is cooled can be expressed as a function of the flow rate of the cooling fluid, other things being equal.

Fiber 16a of FIG. 6 was produced using cooling air at a flow rate of about 10 TrL/sec at the orifice of the bushing and has a mod ratio of about 1.35. The non-circular cross-section fiber 16b shown in FIG. 7 was fabricated with a cooling rate of about 15 mm/sec and has a mod ratio of about 1.45. The fiber 16c shown in FIG.
It has a mod ratio of , and was manufactured with a cooling rate of about 20 m/sec. The non-circular cross-section fiber 16d shown in FIG. 9 has a mod ratio of about 2.70 and has been produced with a cooling rate of about 30 m/sec. Although it is possible to practice the invention using cooling rates of 60 Trt/sec or higher,
It has been found that it is preferable to use a cooling rate of about 40 ml seconds or less when using (below 80 ml) air. especially,
Preferably, the cooling rate is 5.about.30 .mu./sec. Such cooling rates are in sharp contrast to conventional air-cooled bushings, which use cooling rates on the order of approximately 2 to 4 m/sec at the tip of the bushing to prevent flooding. It is.

As shown in FIG. 10, the dimensions of a fiber with a non-circular cross section can be expressed in terms of the mod ratio, which is the outer diameter d. divided by the inner diameter d. Outer diameter d.

is the diameter of the smallest circle that can completely accommodate the cross section of the fiber, and is the inner diameter d.

is the diameter of the largest circle that can be accommodated within the cross section of the fiber.

As shown in FIG. 11, the m o d ratio increases with increasing cooling rate. It was found that the same (mod ratio) increases when the bushing is pressurized.

As shown in FIGS. 12 and 13, a continuous fiber 16d having a cross-section shaped with three radially projecting portions can be used, for example, as a matrix reinforcement for the synthetic resin 32. Mineral fibers according to the present invention can be used to reinforce any organic or inorganic matrix suitable for use with other types of reinforcement. For example, thermoplastic or thermosetting resins such as polyester or epoxy can be reinforced. Furthermore, it can be used to reinforce cement, low melting point metals, silicate matrices, etc. The matrix reinforced with mineral fibers having a non-circular cross section according to the present invention may be simultaneously reinforced with other suitable reinforcing materials such as mineral fibers or organic fibers having a circular cross section.

The bottom wall 12 of the bushing, shown in FIG. It has a non-circular cross section.

As shown in FIG. 18, a tipped bushing can be used to produce fibers with non-circular cross-sections according to the present invention. The three radially outwardly projecting regions 54 of the orifice have enlarged ends 56. An orifice is formed at the bottom end of the closed tubular tip 58.

When practicing the invention with a centrifugal spinner, "vessel" will mean the centrifugal spinner rather than the feeder or bushing, and the non-circular orifice will be in the peripheral wall of the spinner rather than the bottom wall of the bushing. Become.

As shown in FIG. 15, molten glass 40 is fed to a rotating centrifugal spinner 42. As shown in FIG. Molten glass is injected toward the bottom wall 44 of the spinner and flows toward the peripheral wall 46 of the spinner due to centrifugal force. A non-circular orifice 48 is provided in the circumferential wall 46 of the spinner to allow a flow 50 of molten glass to flow through the spinner.
Extending from these orifices 48. The relative motion between the stream of molten glass projected from the centrifugal spinner and the air surrounding the spinner cools and solidifies the stream of molten glass into glass fibers 52. The rate of cooling is controlled to an extent by the rotational speed of the spinner. Blower 54
An annular blower such as can be placed concentrically to the spinner and oriented downwardly so that the fibers can be collected by known means.

The spinner may be adapted to have a non-circular orifice having a slotted shape, a cross shape, and various other shapes. As shown in FIG. 16, the spinner has a crescent-shaped orifice 48 to produce a glass fiber 52 having a cross-sectional shape as shown in FIG.
It may have the following.

Example 1 A continuous fiber of E-glass with a cross-section of three radial protrusions having a mod ratio of approximately 2.3 was
A tipless orifice having 0 similarly shaped orifices was used under the following conditions.

Dimensions of the orifice Depth: 0.38 #1l (0,015 inch) Width of each protrusion: Q, 23 m (0,009 inch) Length of each protrusion measured from the center of the orifice 20.69 m (0.69 m) , 02 finch) Glass temperature: 1,200'C (below 2,190) Glass type: 200E (total) Bushing pressure: 60KPa (8,7t) Si
g) Glass flow rate: 0.26 g/min/hole (0,0341 b/hr/hole) Number of filaments: 20 Orifice pattern: 2 rows, 10 holes/row, staggered row spacing: 3.18 holes (0 , 125 inches) Hole spacing in each row: 3.05M (0,120 inches) Cooling medium: 27℃ (80 below) air Cooling nozzle dimensions: Horizontal 38.1# (1,5 inches) × Vertical direction 6.35 s (0.25 inch) Cooling nozzle position: 25 m (1 inch) from the center line of the bushing (center line between orifice rows) 15 degrees to the horizontal direction Cooling nozzle flow m : 10.2Kg 1 hour (3005c
fh) Cooling rate: 9.8 m/5 (32 ft/s) at the cooling nozzle; 8.8-9.8 m/5 (29-32 ft/s) at the centerline of the bushing > (reduced speed) Winding machine speed near 87 m/s (1,550 feet/min) Average fiber diameter 2M filament 65HT (16,5 μm)
m) Examples 2 and 3 based on the cross-sectional area Using a tipped bushing with 14 holes and with cooling by a fin shield, a continuous piece of E-glass with a cross-sectional shape with three radial projections manufactured glass fiber.

The tip is in the form of a closed tube, and an orifice as shown in FIG. 18 is provided at the bottom of the tip.

The dimensions of this orifice determine the mod ratio of the final fiber. The following conditions were satisfied for all tips.

Tip tube diameter: 3.3M (0,130 inch) Tip tube length: 6.1M (0,240 inch) Tip end thickness (orifice depth) 20,28 m
(0,01'1 inch) Tip pattern: 2 rows, 7 tapes/row, spacing between linear rows - 7,6 m (0,030 in)) Tip spacing within each row - 5,8 tape ( 0,23 inch) Fin shield dimensions: Fin thickness - 1,4 m (0,055 inch) Fin height - 15,9 m (0,625 inch) Fin length - 42,7 μm (1,68 inch) inch) Fin Blade Spacing - 5,8# (0,23 inch) Glass Type: 200E Glass Temperature: 1,230'C (2,250°F>(
All) Bushing pressure nearer, 6 to Pa (1,1 psig
) Winder speed: approximately 3.81 m/sec (750 feet/min); this speed varied somewhat during the experiment.

Doctor 2 Hole dimensions: [)-o, 64 m (0,025 inches) P-
0,51m (0,020 inch) W-0,25# (
0,010 inch) Glass flow rate: 0.14 g/min/hole (0,0'181 b/hour/hole) Average diameter of fiber 2N filament, 70 HT (17,
8 μm) Average mod ratio = 2.2 Hole dimensions: [)-o, 64 m (0,025 inch) P-
0,51 m (0,020 inch) W - 0,13 m (0,005 inch) Glass flow rate: 0,1069/min/hole (0,0141 b/hr/hole) Average diameter of fiber 2L filament, 59 HT (14,
9 μm) Average mod ratio: 5.3 As is clear from the above, the present invention can be practiced with various modifications and changes, and these are also included in the concept of the present invention.

The present invention is particularly useful for the production of glass fibers used as heat insulators, sound insulators, and for reinforcing resin matrices.

[Brief explanation of drawings]

FIG. 1 is a front view of an apparatus for producing continuous glass fibers with non-circular cross sections using bushings in accordance with the principles of the present invention. FIG. 2 is a plan view of the bottom wall of the bushing with a non-circular orifice. 3 is a perspective view showing how a glass fiber having a non-circular cross section is manufactured from the non-circular orifice of FIG. 2. FIG. FIG. 4 is a graph showing fiber properties as a function of distance from the bushing. FIG. 5 is a longitudinal cross-sectional view of a non-circular orifice in accordance with the principles of the present invention. 6 to 9 are cross-sectional views showing non-circular cross-sections of glass fibers manufactured using various cooling conditions. FIG. 10 is an enlarged sectional view of the cross section of FIG. 9. FIG. 11 is a graph showing the relationship between mod ratio and cooling rate. FIG. 12 is an enlarged perspective view of a resin matrix reinforced with fibers having a non-circular cross section. FIG. 13 is an enlarged perspective view of three of the fibers shown in FIG. 12. FIG. 14 is a bottom view showing the bottom wall of a bushing having both circular and non-circular orifices. FIG. 15 is a longitudinal sectional view showing a centrifugal spit to which the present invention is applied. FIG. 16 is a front view of the centrifugal spinner of FIG. 15. FIG. 17 is a cross-sectional view of a glass fiber having a crescent-shaped cross section manufactured by the apparatus shown in FIGS. 15 and 16. FIG. 18 is a plan view showing an example of a non-circular Δ refit with a tip. 10... Flow of molten glass 12... Bottom wall 14... Bushing 16.
... Fiber 18 ... Winding chamber 20 ... Shoe 22 ... Applicator 24 ... Molten glass 26 ... Air nozzle 28.30 ... Orifice 32 ... Resin 40 ... Melt Glass 42・
... Centrifugal spinner 44 ... Bottom wall 46 ... Peripheral wall
48... Orifice 50... Flow of molten glass

Claims (12)

[Claims] (1) A method for producing mineral fibers of non-circular cross section having a mod ratio greater than about 1.2, the method comprising: discharging the molten mineral material as a flow having a non-circular cross-section from a non-circular orifice formed in the wall of the storage container; quenching the stream of molten mineral material such that it hardens as mineral fibers having a non-circular cross-section resembling the shape of the molten mineral material, the initial viscosity of the molten mineral material would have been lower if the quenching had not taken place. A method for producing mineral fibers, characterized in that the cross section of the flow of the molten mineral material is sufficiently low to be circular. (2) The method of claim 1, wherein the ratio of the viscosity (poise) to surface tension (dynes/cm) is in the range of about 0.1 to 25. (3) The manufacturing method according to claim 1, wherein the non-circular orifice is provided in a bushing wall of a feeder for forming continuous glass fibers. (4) The manufacturing method according to claim 1, wherein the non-circular orifice is provided on a peripheral wall of a centrifugal spinner for manufacturing mineral fibers. (5) The pressure of the molten mineral material in the bushing near the orifice is 2,800 Pa (0.
4 psig) to 690,000 Pascal (100 psi
The manufacturing method according to claim 3, characterized in that it falls within the scope of g). (6) A manufacturing method according to claim 3, characterized in that the quenching of the flow of molten mineral fibers is carried out by impinging the flow with a cooling fluid. (7) The quenching of the flow of molten mineral fibers is performed by a fin shield.
The method described in section. (8) The rapid cooling process is performed as follows: Z=(X_7_5σ_o/μ_or_e_o)*(1/
V_o)*1/(MR_o-1)≦2, where X_7_5 is the distance (cm) between the point where the diameter of the flow of molten mineral material reduces to 75% and the bushing, μ_o is the initial viscosity (poise)
where r_e_o is the initial effective fiber diameter (cm), σ_o is the initial surface tension of the molten mineral material (dynes/cm), and V_o is the flow of molten mineral material through the orifice. initial velocity (m/s),
4. The method of claim 3, wherein MR_o is the initial mod ratio of the flow. (9) An apparatus for producing mineral fibers of non-circular cross section having a mod ratio greater than about 1.2, the apparatus comprising: about 1.3 to 2 for storing and discharging said molten mineral material in one or more streams.
a bushing having a wall with an orifice having a mod ratio in the range of 5; and means for quenching the flow of molten mineral material so as to harden it as a fiber, the initial viscosity of the molten mineral material being such that the flow of molten mineral material would be lower in the absence of the quenching. A mineral fiber manufacturing device characterized by having a sufficiently low cross section to have a circular cross section. (10) The manufacturing apparatus according to claim 9, wherein the wall of the bushing is disposed within a feeder for forming continuous glass fiber. (11) The manufacturing apparatus according to claim 9, wherein the wall of the bushing is a peripheral wall of a centrifugal spinner for manufacturing mineral fibers. (12) The manufacturing apparatus according to claim 10, wherein the quenching means has a fin shield.