CA2246283A1 - Bicomponent glass and polymer fibers made by rotary process - Google Patents
Bicomponent glass and polymer fibers made by rotary process Download PDFInfo
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- CA2246283A1 CA2246283A1 CA002246283A CA2246283A CA2246283A1 CA 2246283 A1 CA2246283 A1 CA 2246283A1 CA 002246283 A CA002246283 A CA 002246283A CA 2246283 A CA2246283 A CA 2246283A CA 2246283 A1 CA2246283 A1 CA 2246283A1
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- glass
- fibers
- thermoplastic material
- molten
- polymer
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Classifications
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/04—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor
- C03B37/045—Construction of the spinner cups
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- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/01—Manufacture of glass fibres or filaments
- C03B37/04—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor
- C03B37/05—Manufacture of glass fibres or filaments by using centrifugal force, e.g. spinning through radial orifices; Construction of the spinner cups therefor by projecting molten glass on a rotating body having no radial orifices
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
- C03B37/00—Manufacture or treatment of flakes, fibres, or filaments from softened glass, minerals, or slags
- C03B37/075—Manufacture of non-optical fibres or filaments consisting of different sorts of glass or characterised by shape, e.g. undulated fibres
- C03B37/0753—Manufacture of non-optical fibres or filaments consisting of different sorts of glass or characterised by shape, e.g. undulated fibres consisting of different sorts of glass, e.g. bi-component fibres
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- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
-
- D—TEXTILES; PAPER
- D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
- D04H—MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL; FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING ; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION
- D04H1/00—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres
- D04H1/40—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties
- D04H1/54—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving
- D04H1/56—Non-woven fabrics formed wholly or mainly of staple fibres or like relatively short fibres from fleeces or layers composed of fibres without existing or potential cohesive properties by welding together the fibres, e.g. by partially melting or dissolving in association with fibre formation, e.g. immediately following extrusion of staple fibres
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P40/00—Technologies relating to the processing of minerals
- Y02P40/50—Glass production, e.g. reusing waste heat during processing or shaping
- Y02P40/57—Improving the yield, e-g- reduction of reject rates
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Geochemistry & Mineralogy (AREA)
- Manufacturing & Machinery (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Textile Engineering (AREA)
- Spinning Methods And Devices For Manufacturing Artificial Fibers (AREA)
- Reinforced Plastic Materials (AREA)
- Multicomponent Fibers (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
In a method for making bicomponent glass and polymer fibers, molten glass (A, 90, 99) and molten polymer (B, 92, 97, 98) are supplied to a rotating spinner (10, 72) having an orificed peripheral wall (32, 66, 74). The molten glass and molten polymer are centrifuged through the orifices (56, 70, 84) as molten bicomponent glass and polymer streams. Then the streams are cooled to make bicomponent glass and polymer fibers.
Description
CA 02246283 l998-08-l3 BICOMPONENT GLASS AND POLYMER FIBERS
MADE BY ~OTARY PROCESS
TECHNICAI~ FIEL,D
S This invention relates in general to the m~nllfacture of fibers, and specifically to a method for m~nllfslrturing bicomponent glass and polymer fibers by a modified rotary process.
BACKGl~OUND
Bicomponent polymer fibers have previously been made by a textile 10 process for use in products such as fabrics and hosiery. In this process, two molten polymers are supplied to a stationary spinneret having holes from which fibers are pulled or drawn. The polymers are usually combined to form fibers having a core of one polymer and a surrounding sheath of the other polymer.
The textile process usually makes relatively large diameter bicomponent 15 fibers. For certain applications, there are advantages to using smaller diameter fibers.
Also, the textile process is limited to the use of components having similar melting points, so that the lower melting component does not therm:~lly degrade when exposed to the higher melting component.
Bicomponent glass f1bers have been made by a modified rotary process.
20 Two different types of molten glass are supplied to a rotating spinner having an orificed peripheral wall. The two types of molten glass are centrifuged through the orifices to form bicomponent glass fibers. The fibers are particularly useful in insulation products.
The m~mlf~c.ture of glass fibers is a different field from the m~nllf~ ture of polymer fibers. The two materials have different physical properties such as different 25 viscosities, and usually the softening point of the glass is different from the melting point of the polymer. The technologies for making the fibers are also different.
It has not previously been known to produce bicomponent fibers by combining glass and polymers. ~uch fibers would provide advantages associated with both bicomponent glass fibers and bicomponent polymer fibers, and would have 30 properties and uses not provided by either fiber. Accordingly, it would be desirable to provide a process for mak.ing bicomponent glass and polymer fibers.
W O 97/33841 PCT~US97/03012 DISC~OSU~U~ OF n~VENTION
This invention relates to a method for making multicomponent fibers~ and particularly bicomponent fibers. The bicomponent fibers are forrned from glass and a thermoplastic m~t~ri~l, preferably a polymer. In the method, molten glass and molten 5 thermoplastic m~t.ori7~1 are supplied to a rotating spinner having an orificed peripheral wall. Preferably the t~ dl~lre at which the glass viscosity is 1000 poise is from about 200~C to about 495~C, and the melting point of the therrnoplastic material is from about 200~C to about 345~C. The coefficient of thermal expansion of the thermoplastic material is preferably higher than that of the glass by an amount greater than about 10 10 ppm/~C. The molten glass and molten thermoplastic material are centrifuged through the orifices as molten bicomponent streams of glass and thermoplastic material. Then the streams are cooled to make bicomponent fibers of glass and therrnoplastic material.
The bicomponent fibers of glass and thermoplastic material produced by the method arc novel and provide advantages associated with both bicomponent glass 15 fibers and bicomponent polymer fibers. They also have properties and uses not provided by either of the previously known fibers.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a sehem~tic view in elevation of apparatus for carrving out the rotary method of the invention for m~king bicomponent fibers of glass and polymer.
Fig. 2 is a cross-sectional view in elevation of a spinner by which bicomponent fibers of glass and polymer can be produced according to the invention.
Fig. 3 is a schematic view in perspective of a portion of the spinner of Fig.
MADE BY ~OTARY PROCESS
TECHNICAI~ FIEL,D
S This invention relates in general to the m~nllfacture of fibers, and specifically to a method for m~nllfslrturing bicomponent glass and polymer fibers by a modified rotary process.
BACKGl~OUND
Bicomponent polymer fibers have previously been made by a textile 10 process for use in products such as fabrics and hosiery. In this process, two molten polymers are supplied to a stationary spinneret having holes from which fibers are pulled or drawn. The polymers are usually combined to form fibers having a core of one polymer and a surrounding sheath of the other polymer.
The textile process usually makes relatively large diameter bicomponent 15 fibers. For certain applications, there are advantages to using smaller diameter fibers.
Also, the textile process is limited to the use of components having similar melting points, so that the lower melting component does not therm:~lly degrade when exposed to the higher melting component.
Bicomponent glass f1bers have been made by a modified rotary process.
20 Two different types of molten glass are supplied to a rotating spinner having an orificed peripheral wall. The two types of molten glass are centrifuged through the orifices to form bicomponent glass fibers. The fibers are particularly useful in insulation products.
The m~mlf~c.ture of glass fibers is a different field from the m~nllf~ ture of polymer fibers. The two materials have different physical properties such as different 25 viscosities, and usually the softening point of the glass is different from the melting point of the polymer. The technologies for making the fibers are also different.
It has not previously been known to produce bicomponent fibers by combining glass and polymers. ~uch fibers would provide advantages associated with both bicomponent glass fibers and bicomponent polymer fibers, and would have 30 properties and uses not provided by either fiber. Accordingly, it would be desirable to provide a process for mak.ing bicomponent glass and polymer fibers.
W O 97/33841 PCT~US97/03012 DISC~OSU~U~ OF n~VENTION
This invention relates to a method for making multicomponent fibers~ and particularly bicomponent fibers. The bicomponent fibers are forrned from glass and a thermoplastic m~t~ri~l, preferably a polymer. In the method, molten glass and molten 5 thermoplastic m~t.ori7~1 are supplied to a rotating spinner having an orificed peripheral wall. Preferably the t~ dl~lre at which the glass viscosity is 1000 poise is from about 200~C to about 495~C, and the melting point of the therrnoplastic material is from about 200~C to about 345~C. The coefficient of thermal expansion of the thermoplastic material is preferably higher than that of the glass by an amount greater than about 10 10 ppm/~C. The molten glass and molten thermoplastic material are centrifuged through the orifices as molten bicomponent streams of glass and thermoplastic material. Then the streams are cooled to make bicomponent fibers of glass and therrnoplastic material.
The bicomponent fibers of glass and thermoplastic material produced by the method arc novel and provide advantages associated with both bicomponent glass 15 fibers and bicomponent polymer fibers. They also have properties and uses not provided by either of the previously known fibers.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a sehem~tic view in elevation of apparatus for carrving out the rotary method of the invention for m~king bicomponent fibers of glass and polymer.
Fig. 2 is a cross-sectional view in elevation of a spinner by which bicomponent fibers of glass and polymer can be produced according to the invention.
Fig. 3 is a schematic view in perspective of a portion of the spinner of Fig.
2.
Fig. 4 is a sçhem~tic view in elevation of the spinner of Fig. 2, taken along 25 line 4-4 of Fig. 2.
Fig. 5 is a plan view of a portion of a second embodiment of a spinner for making bicomponent fibers of glass and polymer.
Fig. 6 is a cross-sectional view in elevation of a third embodiment of a , .
spinner for making bicomponent fibers of glass and polymer.
Fig. 7 is a cross-sectional view in elevation of the orifice of the spinner of Fig. 6.
CA 02246283 l998-08-l3 W O 97/33841 PCT~US97/03012 Fig. 8 is a s~h.em~tic cross-sectional view of a bicomponent fiber of glass and polymer produced according to the invention.
Fig. ~ is a s~hem~tic cross-sectional view of a bicomponent fiber of glass ,~ and polymer in which differing viscosities of the glass and polymer enables the lower S viscosity polymer to flow partially around the higher viscosity glass.
l~ig. 10 is a schematic cross-sectional view of a bicomponent fiber of glass and polymer in which the differing viscosities ena~les the lower viscosity polymer to nearly enclose the higher viscosity glass.
Fig. 11 is a schematic cross-sectional view of a bicomponent fiber of glass 10 and polymer in which the lower viscosity polymer flows all the way around the higher viscosity glass to enclose the glass and form a cl~d-lin~.
Fig. 12 is a srh~m~tic cross-sectional view of a tricomponent fiber formed of glass and two different polymers.
BEST MODE FO~ CARRYING OUT THE INVENTIQN
Fig. 1 illustrates a rotary fiber forming process for m~kin~v insulation products from bicomponent fibers of glass and polymer in accordance with this invention.
It is understood, however, that different fabrication processes can be used with the fibers to make textiles, filtration products, and other products. ~uch processes include stitching, neetllin~, hydro-entanglement, and encapsulation. It is also understood that 20 multicomponent fibers other than bicomponent fibers are included in the invention, and that the fibers can be formed from other thermoplastic materials such as asphalt in addition to polymers.
In the illustrated process, molten glass and molten polymer are supplied to spinners 10. The molten glass is supplied from any suitable source such as furnace 11 25 and forehearth 13. The molten polymer is supplied from any suitable source. For example, hopper 12 cont~inin~ polymer granules can be connected to extruder 14 where the polymer is melted and then supplied to the spinners. As will be described below, the spinners produce veils 16 of bicomponent fibers of glass and polymer. The fibers are directed downwardly by any means, such as by annular blower 18. As the fibers are 30 blown downwardly, they are ~tt~nn~tecl and cooled. The fibers are collected as a wool pack 20 on any suitable surface, such as conveyor 22. A partial vacuum, not shown, can be positioned beneath the conveyor to facilitate fiber collection.
W O97/33841 PCT~US97103012The wool pack of bicomponent fibers of glass and polymer may then optionally be passed through a station for further processing, such as oven 24. While passing through the oven, the wool pack is preferably shaped by top conveyor ~6 and bottom conveyor 28, and by edge guides (not shown). The wool pack exits the oven as S insulation product 30.
As shown in Fig. 2, each spinner 10 includes a peripheral wall 32 and a bottom wall 34. The spinner is rotated on any suitable means, such as spindle 36, as is known in the art. The rotation of the spinner centrifuges molten glass and molten polymer through orifices in the peripheral wall to form bicomponent fibers 38 of glass 10 and polymer, in a manner described in greater detail below. The spinner preferably rotates at a speed from about 1200 rpm to about 3000 rpm. Spinners of various diameters can be used, and the rotation rates adjusted to give the desired radial acceleration at the inner surface of the peripheral wall. The spinner diameter is preferably from about 20 centimeters to about ~ 00 centimeters. The radial acceleration (velocity2/radius) at the 15 inner surface of the peripheral wall is preferably from about 4,500 meters/second2 to about 14,000 meters/second2, and more preferably from about 6,000 meters/second2 to about 9,000 meters/second2.
Annular blower 18 is positioned to direct the fibers downwardly for collection on the conveyor as shown in Fig. 1. Optionally the annular blower can use 20 in~ ce~l air 40 to further ~tt~n~l~te the fibers.
Preferably the interior of the spinner is heated by any heating means (not shown) such as by blowing in hot air or other gas. The temperature of the sprnner is preferably from about 1 50~C to about 450~C but can vary depending on the type of glass and polymer.
A heating means such as annular hot air supply 42 can optionally be positioned outside the spinner to heat either the spinner or the fibers, to facilitate the fiber ~tten~ tion and m:~intzlin the temperature of the spinner at the level for o~Lilllulll centrifugation of the glass and polymer. ., The interior of the spinner is supplied with separate streams of molten 30 glass and molten polymer, a first stream cont~ining glass and a second stream Cont~ining polymer. If desired, the streams of molten glass and molten polymer can be supplied by injection under pressure. The molten glass in the first stream drops from a first delivery W O 97/33841 PCT~US97/03012 tube 44 directly onto the bottom wall and flows outwardly due to the centrifugal force toward the peripheral wall to form a head of glass indicated as "A" in Fig. 2. The molten polymer, delivered via a second delivery tube 46, is positioned closer to the peripheral ., wall than the first stream, and molten polymer is intercepted by annular horizontal flange 5 48 before it can reach the bottom wall. Thus, a build-up or head of molten polymer, indicated as "B" in Fig. 2, is formed above the horizontal flange as shown. It is understood that the molten glass and molten polymer could also be supplied so that the molten glass is intercepted by the annular horizontal flange and the molten polymer drops to the bottom wall.
As shown in ~ig. 3, the spinner is adapted with a vertical interior wall 50 which is generally circumferential and positioned radially inwardly from the peripheral wall 32. A series of vertical baffles 52, positioned between the peripheral wall and the vertical interior wall, divide that space into a series of generally vertically-aligned cc,lllpal .ll,ents 54 which run substantially the entire height of the peripheral wall. It can 15 be seen that the horizontal flange, vertical interior wall, and vertical baffles together comprise a divider for directing the molten glass "A" and molten polymer "B" into alternate adjacent con~l."ents so that every other com~alLlnent contains molten glass "A" while the rem~inin~ coll~al kllents contain molten polymer "B".
The peripheral wall is adapted with orifices 56 which are positioned 20 adjacent the radially outward end of the vertical baffle. Each orifice has a width greater than the width of the vertical baffle, thereby enabling a flow of both molten glass "A" and molten polymer "B" to emerge from the orifice as a single bicomponent fiber of glass and polymer. As can be seen in Fig. 3, each compartment 54 runs the entire height of the peripheral wall 32 with orifices along the entire vertical baffle separating the25 co~ ~lrllents. Preferably, the peripheral wall has from about 200 to about 5,000 orifices, depending on the spinner diameter and other process parameters.
As shown in Fig. 4, the orifices 56 are in the shape of slots, although other shapes of orifices can be used. The molten glass "A" usually has a higher viscosity than the molten polymer "B" at the temperature of the peripheral wall. Consequently, an 30 orifice perfectly centered about the vertical baffle would be expected to emit a higher throughput of the lower viscosity polymer than the throughput of the higher viscosity glass. One method to counteract this tendency and to balance the throughputs of the W O 97/33841 PCT~US97/03012 molten glass and molten polymer, is to increase the height of the head of molten glass "A"
relative to the height of the head of molten polymer "B". Another method to balance the throughputs of the molten glass and molten polymer is to position the slot orifice so that it is offset from the centerline of the vertical baffle 52. As shown in Fig. 4, the orifice will S have a smaller end 58 which will restrict the flow of the lower viscosity polymer "B", and a larger end 60 which will enable a comparable flow or throughput of the higher viscosity glass "A". Another method to balance the throughputs of the molten glass and molten polymer is to restrict the flow of polymer into the alternate compartments cont~ininp the low viscosity polymer, thereby partially starving the holes so that the throughputs of 10 molten glass and molten polymer are roughly equivalent. The orifice can also be centered about the vertical baffle when the molten glass and molten polymer have similar viscosities or when different throughputs are desirable.
Fig. S illustrates a portion of a second embodiment of the spinner. Like the first embodiment shown in Fig. 4, the spinner is adapted with vertical baffles 62 15 exten~1ing between a vertical interior wall 64 and the peripheral wall 66 to form compartments 68. The peripheral wall is adapted with rows of orifices 70 which are positioned adjacent the radial outward end of the vertical baffle. The orifices are in the shape of a "V", with one end or leg leading into a compal ~lllent cont~inin~ molten glass "A" and one leg leading into a compartment cont~ining molten polymer "B". The flows 20 of both molten glass "A" and molten polymer "B" join and emerge from the orifice as a single bicomponent fiber of glass and polymer.
Fig. 6 illustrates a third embodiment of the spinner. The spinner 72 includes a peripheral wall 74 and a bottom wall 76. The bottom wall slants upwardly as it approaches the peripheral wall. The interior of the spinner is supplied with separate 25 streams of molten glass and molten polymer. The molten glass in the first stream drops from a first delivery tube 78 directly onto the bottom wall and flows outwardly and upwardly due to centrifugal force toward the peripheral wall to form a head of molten glass indicated as "A" in Fig. 6. The molten polymer, delivered via a second delivery tube 80, is positioned closer to the peripheral wall than the first stream, and the molten 30 polymer is intercepted by annular horizontal flange 82 before it can reach the bottom wall.
Thus, a build-up or head of molten polymer, indicated as "B" in Fig. 6, is formed above the horizontal flange as shown.
W O 97/33841 PCT~US97/03012 The peripheral wall is adapted with a row of orifices 84 around its circumference, the orifices being positioned adjacent the radially outward end of the horizontal flange. As can be seen in Fig. 7, each orifice is in the shape of a "Y", with one arm leading to the molten glass "A", the other arrn leading to the molten polymer "B", and 5 the base leading to the exterior of the peripheral wall. The flows of both molten glass and ~ molten polymer join and emerge ~rom the orifice as a single bicomponent fiber 86 of glass and polymer.
Other spinner configurations can also be used to supply streams of molten glass and molten polymer to the spinner orifices.
The bicomponent fibers of this invention can be formed from many different kinds of glass and thermoplastic material. Usually the softening point of glass is significantly higher than the melting point of a thermoplastic material. Under ordinary circumstances, if molten thermoplastic material is exposed to the higher temperature of molten glass, there is a problem of thermal degradation of the thermoplastic material. It is 15 believed that the bicomponent fibers formed by the rotary process of this invention substantially avoid thermal degradation of the thermoplastic material. The molten bicomponent streams are formed, centrifuged and cooled so rapidly that the molten thermoplastic material is exposed to the higher temperature of the molten glass for only a fraction of a second. The spinner can be provided with an inert atmosphere or insulating 20 material between the molten glass and the molten thermoplastic material to further avoid any signif1cant thermal degradation.
Generally, however, the bicomponent fibers of this invention are formed from a low softening glass and a high melting thermoplastic material so that the two components have similar fiber forming temperatures. For purposes of this invention, the 25 glass will be characterized by the temperature at which its viscosity is 1000 poise, as measured according to ASTM C965. The thermoplastic material will be characterized by its melting point as determined using DSC (Differential Scannin~ Calorimetry). It is understood that use of the term "melting point" does not strictly apply to some classes of thermoplastic materials, specifically amorphous materials. In such cases, the term 30 "melting point" means the temperature at which the material softens and is easily flowable so that it can be fiberized, as known to persons skilled in the art.
WO 97/33841 PCTAUS97/03012Preferably the temperature at which the viscosity of the glass is 1000 poise is within about 200~C of the melting point of the thermoplastic material~ more preferably within about 1 50~C, and most preferably within about 1 00~C. The temperature at which the viscosity of the glass is 1000 poise is less than about 600~C, preferably less than about 5 550~C, more preferably less than about 500~C, more preferably from about 200~C to about 495~C, and most preferably from about 260~C to about 445~C. The melting point ofthe thermoplastic material is above about 140~C, preferably from about 200~C to about 345~C, and more preferably from about 260~C to about 345~C. The glass and thermoplastic material can be modifled to adjust these temperatures.
Preferred low softening glasses are high-borate glasses and high-phosphate glasses. The term "high-borate glass" means that the glass composition has a B2O3 content greater than about 8% by weight of the total glass composition. A particularly preferred high-borate glass has a composition by weight percent of from about 0% to about 10% SiO2, from about 0% to about 8% Al2O3, from about 70% to about 92% PbO, 15 and from about 8% to about 25% B2O3. The temperature at which the viscosity of a high-borate glass is 1000 poise is usually from about 300~C to about 500~C. Some examples of the compositions by weight% of suitable high-borate glasses, and the temperature at which their viscosity is 1000 poise, are shown below in Table I:
Table I
B2O3 9 7 19.6 9.6 18.6 10 9.9 SiO2 0.8 0.6 10.4 5 5 PbO 89.5 79.8 80 74.6 82 80.2 Al2O3 6.8 3 AlF3 4.9 T (~C) 427 494 538 497 431 399 The term "high-phosphate glass" means that the glass composition has a P2O5 content greater than about 20% by weight of the total glass composition. A
particularly ~-c;r~llcd high-phosphate glass has a composition by weight percent of from about 50% to about 80% P2Os, from about 10% to about 30% Na2O and K2O, from about 0% to about 30% PbO, from about 0% to about 7% Al2O3, and from about 0% to about 7 15% other oxides such as ZnO, MgO, CaO, SnO and BaO. The temperature at which the viscosity of a high-phosphate glass is 1000 poise is usually from about 200~C to about W O 97/33841 PCT~US97/03012 500~C. Some examples of the compositions by weight% of suitable high-phosphate gl~çs, and the temperature at which their viscosity is 1000 poise, are shown below in Table II:
Table II
P2O561.2 71.8 59.2 27.4 26 19 Na2O6.5 K2O 9.8 19.6 19 ZnO 4.3 2.1 4.1 PbO11.6 11.3 10.7 7.2 9.3 AlF36.6 6.5 6.4 SnO 37.8 30.8 25.8 S~2 24 35.9 45.9 T(~C)530 499 492 289 247 179 If desired or necessary, additives such as fluorides or other halides, 15 th~ m oxide or alkali oxides can be added to the glass to lower the tRmperature at which its viscosity is 1000 poise. A preferred low softening glass cont~ining fluorine is disclosed in U.S. ~at. No. 4,379,070 to Fick, and in Phys. & Chem. Glasses, Vol. 70, pp.
49-55, 1988. Other low softening ~ sçs, and mixtures of glasses, can also be used.
The thermoplastic material used for forming the mul~icomponent fibers 20 can be selected from a w;de variety of suitable thermoplastic materials known for use in m~king fibers. Preferred high melting thermoplastic materials are selected from the following polymers: poly(phenylene sulfide) ("PPS"), poly(ethylene terephthz~ e)("PET"), poly(butylene terephth~l~qte) ("PBT"), polycarbonate, polyamide, and mixtures thereof. Polyolefins and asphalt are also suitable but less preferred because they are 25 somewhat lower melting or so~~rPning. Other high melting thermoplastic materials, amorphous thermoplastic materials, and mixtures of thermoplastic materials, can also be used.
An advantage of the rotary process of this invention is that the viscosities of the molten glass and molten thermoplastic material are not required to be close to one 30 another. The two viscosities can be significantly different and the process still forms suitable multicomponent fibers. Usually the viscosity of molten glass is higher than the viscosity of a molten thermoplastic material. In a specific embodiment of this invention, W O 97/33841 PCTnJS97/03012 the viscosity of the glass, at the temperature of the peripheral wall of the spinner, is higher than that of the thermoplastic material by a factor within the range of from about 5 to about 1000, and usually from about 50 to about 500.
The bicomponent fibers of this invention have a very irregular, curvilinear 5 nature due to the difference in therrnal expansion coeff1cients of the glass and thermoplastic material. Such a curvilinear nature is particularly advantageous for giving the fibers excellent insulating properties when they are used in in~ ting materials or textiles. As the fiber cools, the thermoplastic material contracts at a faster rate than the glass. The result is stress upon the fiber, and to relieve the stress, the fiber must bend into l O a curve. Preferably the coefficient of thermal expansion of the thermoplastic material is higher than that of the glass by an amount greater than about 10 ppm/~C, more preferably greater than about 30 ppm~~C, more preferably greater than about 50 pprn/~C, and most preferably greater than about 70 ppm~~C. Usually the glass has a coefficient of thermal expansion from about 5 ppm~~C to about 30 ppm/~C, while the thermoplastic material is a 15 polymer having a coefficient of thermal expansion from about 80 ppm/~C to about 120 ppm/~C.
The bicomponent fibers made by the rotary process of this invention can be formed having a smaller diameter than bicomponent fibers made by a textile process.
This advantage is provided because the rotary process uses centrifugal force to attenuate 20 the fibers instead of relying on the mechanical ~tten~l~tion of the textile process.
Preferably the bicomponent fibers have an average outside diameter of from about 2 microns to about 50 microns, and more preferably from about 5 microns to about 40 microns.
Each of the bicomponent fibers of the present invention is composed of 25 glass and thermoplastic mzltPri~l. If one were to make a cross-section of an ideal bicomponent fiber, one half of the fiber would be glass and the other half would be thermoplastic m~tPri~l In reality, a wide range of proportions of the amounts of glass and thermoplastic material may exist in the fibers, or perhaps even over the length of an individual fiber. The pcrcentage of glass may vary within the range of from about 5% to 30 about 9S% by volume of the total fiber, with the remainder being thermoplastic mzltPri~
In general, a group of fibers such as a wool pack will have many different combinations of percentages of glass and thermoplastic material, including a small fraction of fibers that W O 97/33841 PCTrUS97/03012 are single component. The pl~r~llc;d composition of the bicomponent fibers will differ depending on the application. For some applications, preferably the bicomponent fibers comprise, by volume, from about 40% to about 60% glass and from about 40% to about 60% thermoplastic material.
Cross-section photographs of fibers can be obtained by mounting a bundle of fibers in epoxy with the fibers oriented in parallel as much as possible. The epoxy plug is then cross-sectioned and polished. The polished sample surface is then coated with a thin carbon layer to provide a conductive sample for analysis by ~c~nnin~ electron microscopy (SEM). The sample is then ç~ ned on the SEM using a backscattered-10 electron detector, which displays variations in average atomic number as a variation in the gray scale. For exarnple, this analysis reveals the presence of glass and polymer by a darker and lighter region on the cross-section of the fiber, and shows the interface of the glass and polymer.
As shown in Fig. 8, if the glass/polymer ratio is 50:50, the interface 88 15 between the glass 90 and the polymer 92 passes through the center 94 of the fiber cross-section. As shown in Fig. 9, where the molten polymer has a lower viscosity than the molten glass, the polymer 92 can somewhat bend around or wrap around the glass 90 so that the interface 88 becomes curved. This requires that the bicomponent glass and polymer fiber stream em~n~tin~ from the spinner be m~inf~ined at a temperature 20 sufficient to enable the low viscosity molten polymer to flow around the higher viscosity molten glass. Adjustments in the spinner operating parameters, such as hot air flow rate, blower ples~ule, and polymer or glass temperature, may be necessary to achieve the desired wrap of the low viscosity polymer.
As shown in Fig. 10, the lower viscosity polymer 92 has flowed almost all 25 the way around the higher viscosity glass 90. One way to quantify the extent to which the lower viscosity polymer flows around the higher viscosity glass is to measure the angle of wrap, such as the angle alpha shown in Fig. 10. In some cases the lower viscosity - polymer flows around the higher viscosity glass to forrn an angle alpha of at least 270 degrees, i.e., the lower viscosity polymer flows around the higher viscosity glass to an 30 extent that at least 270 degrees of the circumferential surface 96 of the bicomponent glass and polymer fiber is made up of the polymer.
CA 02246283 l998-08-l3 W O 97/33841 PCT~US97/03012 As shown in Fig. 11, under certain conditions the polymer 92 can flow all the way around the glass 90 so that the polymer encloses the glass to form a clz~ ing In that case, the entire circurnferential surface 96 (360 degrees~ of the bicomponent glass and polymer fiber is the polymer.
The method of the invention is not limited to bicomponent fibers, but rather includes other multicomponent fibers of glass and thermoplastic material such as the tricomponent fiber illustrated in Fig. 12. To form this tricomponent fiber, separate strearns of first and second molten polymers 97 and 98 and molten glass 99 are supplied to a rotating spinner having an orificed peripheral wall. The first and second molten 10 polymers and molten glass are m~int~ined separate until combined in the orifices. One method is to use a spinner having a single row of orifices like in Fig. 6, but where the area above the annular hori~ontal flange 82 is separated into alternate compartments like in Fig. 5. Thus, two streams could be fed into each orifice from above the flange while a third stream is fed into each orifice from below the flange. Other spinner structures can 15 also be used. The first and second molten polymers and molten glass are centrifuged through the orifices as a molten tricomponent stream, and the tricomponent stream is m~in~ined at a temperature sufficient to enable one of the lower viscosity polymers 97 to flow around at least the molten glass 99. Upon cooling of the tricomponent stream, a tricomponent fiber is forrned. Another method to form a tricomponent fiber is to form a 20 molten bicomponent stream of glass and a blend of two polymers, where the polymers have different physical properties so that they separate from one another upon cooling to form fibers. The multicomponent fibers can also include more than three components.
The above descriptions and comparisons of the physical properties of glass and thermoplastic material apply to each of the materials of a multicomponent fiber.2~ Bicomponent fibers in accordance with this invention include fibers in which the glass and the thermoplastic material are disposed in side by side relation with one another. The rotary Ll~d~d~llS described above usually forms such side by side bicomponent fibers. The bicomponent fibers of this invention also include fibers in which one of the glass and the thermoplastic material forms a core, while the other forms 30 a sheath surrounding the core. The rotary apparatus can be specially constructed by methods known in the art to form sheath and core bicomponent fibers. In general, such apparatus feeds one molten component through orifices which form a sheath, and feeds W O 97/33841 PCTrUS97/03012 the other molten component into the interior of the sheath to form a core. Combinations of different kinds of fibers can also be formed. The multicomponent fibers of the invention can also be shaped fibers, produced by shaping the orifice so that fibers are formed having a non-circular cross section. Methods of m~mlf~cturing shaped fibers are 5 disclosed in U.S. Patent Nos. 4,636,234 and 4,666,485 to Huey et al.
Bicomponent fibers of glass and polymer of this invention could be formed according to the following example. The glass used to make the fibers is a high-borate glass. The temperature at which the glass has a viscosity of 1000 poise is about 399~C.
The glass has a coefficient of thermal expansion of about 10 ppm/~C. The polymer used 10 to make the fibers is poly(phenylene sulfide). The polymer has a melting point of about 2~5~C and a coefficient of thermal expansion of about 100 ppm/~C. Separate streams of molten glass and molten polymer are supplied to the spinner illustrated in Figs. 2 and 3 having a temperature of about 360~C at the peripheral wall. At this temperature, the viscosity of the glass is about 5,600 poise and the viscosity of the polymer is about 3,000 15 poise. The spinner has a diameter of about 38 cm and is rotated to provide a radial acceleration of about 7,600 meters/second2. The spinner peripheral wall is adapted with 350 orifices. Bicomponent streams of molten glass and molten polymer are centrifuged through the orifices. The streams are cooled to make bicomponent glass and polymer fibers which are collected as a wool pack. The average outside diameter of the fibers is 20 about 25 microns.
The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specif1cally explained and illustrated without departing from its spirit or scope.
INDUSTRIAL APPLICABILITY
The multicomponent fibers of this invention are useful in many applications including apparel products, thermal and acoustical insulation products, - filtration products, and as binders in composite materials.
Fig. 4 is a sçhem~tic view in elevation of the spinner of Fig. 2, taken along 25 line 4-4 of Fig. 2.
Fig. 5 is a plan view of a portion of a second embodiment of a spinner for making bicomponent fibers of glass and polymer.
Fig. 6 is a cross-sectional view in elevation of a third embodiment of a , .
spinner for making bicomponent fibers of glass and polymer.
Fig. 7 is a cross-sectional view in elevation of the orifice of the spinner of Fig. 6.
CA 02246283 l998-08-l3 W O 97/33841 PCT~US97/03012 Fig. 8 is a s~h.em~tic cross-sectional view of a bicomponent fiber of glass and polymer produced according to the invention.
Fig. ~ is a s~hem~tic cross-sectional view of a bicomponent fiber of glass ,~ and polymer in which differing viscosities of the glass and polymer enables the lower S viscosity polymer to flow partially around the higher viscosity glass.
l~ig. 10 is a schematic cross-sectional view of a bicomponent fiber of glass and polymer in which the differing viscosities ena~les the lower viscosity polymer to nearly enclose the higher viscosity glass.
Fig. 11 is a schematic cross-sectional view of a bicomponent fiber of glass 10 and polymer in which the lower viscosity polymer flows all the way around the higher viscosity glass to enclose the glass and form a cl~d-lin~.
Fig. 12 is a srh~m~tic cross-sectional view of a tricomponent fiber formed of glass and two different polymers.
BEST MODE FO~ CARRYING OUT THE INVENTIQN
Fig. 1 illustrates a rotary fiber forming process for m~kin~v insulation products from bicomponent fibers of glass and polymer in accordance with this invention.
It is understood, however, that different fabrication processes can be used with the fibers to make textiles, filtration products, and other products. ~uch processes include stitching, neetllin~, hydro-entanglement, and encapsulation. It is also understood that 20 multicomponent fibers other than bicomponent fibers are included in the invention, and that the fibers can be formed from other thermoplastic materials such as asphalt in addition to polymers.
In the illustrated process, molten glass and molten polymer are supplied to spinners 10. The molten glass is supplied from any suitable source such as furnace 11 25 and forehearth 13. The molten polymer is supplied from any suitable source. For example, hopper 12 cont~inin~ polymer granules can be connected to extruder 14 where the polymer is melted and then supplied to the spinners. As will be described below, the spinners produce veils 16 of bicomponent fibers of glass and polymer. The fibers are directed downwardly by any means, such as by annular blower 18. As the fibers are 30 blown downwardly, they are ~tt~nn~tecl and cooled. The fibers are collected as a wool pack 20 on any suitable surface, such as conveyor 22. A partial vacuum, not shown, can be positioned beneath the conveyor to facilitate fiber collection.
W O97/33841 PCT~US97103012The wool pack of bicomponent fibers of glass and polymer may then optionally be passed through a station for further processing, such as oven 24. While passing through the oven, the wool pack is preferably shaped by top conveyor ~6 and bottom conveyor 28, and by edge guides (not shown). The wool pack exits the oven as S insulation product 30.
As shown in Fig. 2, each spinner 10 includes a peripheral wall 32 and a bottom wall 34. The spinner is rotated on any suitable means, such as spindle 36, as is known in the art. The rotation of the spinner centrifuges molten glass and molten polymer through orifices in the peripheral wall to form bicomponent fibers 38 of glass 10 and polymer, in a manner described in greater detail below. The spinner preferably rotates at a speed from about 1200 rpm to about 3000 rpm. Spinners of various diameters can be used, and the rotation rates adjusted to give the desired radial acceleration at the inner surface of the peripheral wall. The spinner diameter is preferably from about 20 centimeters to about ~ 00 centimeters. The radial acceleration (velocity2/radius) at the 15 inner surface of the peripheral wall is preferably from about 4,500 meters/second2 to about 14,000 meters/second2, and more preferably from about 6,000 meters/second2 to about 9,000 meters/second2.
Annular blower 18 is positioned to direct the fibers downwardly for collection on the conveyor as shown in Fig. 1. Optionally the annular blower can use 20 in~ ce~l air 40 to further ~tt~n~l~te the fibers.
Preferably the interior of the spinner is heated by any heating means (not shown) such as by blowing in hot air or other gas. The temperature of the sprnner is preferably from about 1 50~C to about 450~C but can vary depending on the type of glass and polymer.
A heating means such as annular hot air supply 42 can optionally be positioned outside the spinner to heat either the spinner or the fibers, to facilitate the fiber ~tten~ tion and m:~intzlin the temperature of the spinner at the level for o~Lilllulll centrifugation of the glass and polymer. ., The interior of the spinner is supplied with separate streams of molten 30 glass and molten polymer, a first stream cont~ining glass and a second stream Cont~ining polymer. If desired, the streams of molten glass and molten polymer can be supplied by injection under pressure. The molten glass in the first stream drops from a first delivery W O 97/33841 PCT~US97/03012 tube 44 directly onto the bottom wall and flows outwardly due to the centrifugal force toward the peripheral wall to form a head of glass indicated as "A" in Fig. 2. The molten polymer, delivered via a second delivery tube 46, is positioned closer to the peripheral ., wall than the first stream, and molten polymer is intercepted by annular horizontal flange 5 48 before it can reach the bottom wall. Thus, a build-up or head of molten polymer, indicated as "B" in Fig. 2, is formed above the horizontal flange as shown. It is understood that the molten glass and molten polymer could also be supplied so that the molten glass is intercepted by the annular horizontal flange and the molten polymer drops to the bottom wall.
As shown in ~ig. 3, the spinner is adapted with a vertical interior wall 50 which is generally circumferential and positioned radially inwardly from the peripheral wall 32. A series of vertical baffles 52, positioned between the peripheral wall and the vertical interior wall, divide that space into a series of generally vertically-aligned cc,lllpal .ll,ents 54 which run substantially the entire height of the peripheral wall. It can 15 be seen that the horizontal flange, vertical interior wall, and vertical baffles together comprise a divider for directing the molten glass "A" and molten polymer "B" into alternate adjacent con~l."ents so that every other com~alLlnent contains molten glass "A" while the rem~inin~ coll~al kllents contain molten polymer "B".
The peripheral wall is adapted with orifices 56 which are positioned 20 adjacent the radially outward end of the vertical baffle. Each orifice has a width greater than the width of the vertical baffle, thereby enabling a flow of both molten glass "A" and molten polymer "B" to emerge from the orifice as a single bicomponent fiber of glass and polymer. As can be seen in Fig. 3, each compartment 54 runs the entire height of the peripheral wall 32 with orifices along the entire vertical baffle separating the25 co~ ~lrllents. Preferably, the peripheral wall has from about 200 to about 5,000 orifices, depending on the spinner diameter and other process parameters.
As shown in Fig. 4, the orifices 56 are in the shape of slots, although other shapes of orifices can be used. The molten glass "A" usually has a higher viscosity than the molten polymer "B" at the temperature of the peripheral wall. Consequently, an 30 orifice perfectly centered about the vertical baffle would be expected to emit a higher throughput of the lower viscosity polymer than the throughput of the higher viscosity glass. One method to counteract this tendency and to balance the throughputs of the W O 97/33841 PCT~US97/03012 molten glass and molten polymer, is to increase the height of the head of molten glass "A"
relative to the height of the head of molten polymer "B". Another method to balance the throughputs of the molten glass and molten polymer is to position the slot orifice so that it is offset from the centerline of the vertical baffle 52. As shown in Fig. 4, the orifice will S have a smaller end 58 which will restrict the flow of the lower viscosity polymer "B", and a larger end 60 which will enable a comparable flow or throughput of the higher viscosity glass "A". Another method to balance the throughputs of the molten glass and molten polymer is to restrict the flow of polymer into the alternate compartments cont~ininp the low viscosity polymer, thereby partially starving the holes so that the throughputs of 10 molten glass and molten polymer are roughly equivalent. The orifice can also be centered about the vertical baffle when the molten glass and molten polymer have similar viscosities or when different throughputs are desirable.
Fig. S illustrates a portion of a second embodiment of the spinner. Like the first embodiment shown in Fig. 4, the spinner is adapted with vertical baffles 62 15 exten~1ing between a vertical interior wall 64 and the peripheral wall 66 to form compartments 68. The peripheral wall is adapted with rows of orifices 70 which are positioned adjacent the radial outward end of the vertical baffle. The orifices are in the shape of a "V", with one end or leg leading into a compal ~lllent cont~inin~ molten glass "A" and one leg leading into a compartment cont~ining molten polymer "B". The flows 20 of both molten glass "A" and molten polymer "B" join and emerge from the orifice as a single bicomponent fiber of glass and polymer.
Fig. 6 illustrates a third embodiment of the spinner. The spinner 72 includes a peripheral wall 74 and a bottom wall 76. The bottom wall slants upwardly as it approaches the peripheral wall. The interior of the spinner is supplied with separate 25 streams of molten glass and molten polymer. The molten glass in the first stream drops from a first delivery tube 78 directly onto the bottom wall and flows outwardly and upwardly due to centrifugal force toward the peripheral wall to form a head of molten glass indicated as "A" in Fig. 6. The molten polymer, delivered via a second delivery tube 80, is positioned closer to the peripheral wall than the first stream, and the molten 30 polymer is intercepted by annular horizontal flange 82 before it can reach the bottom wall.
Thus, a build-up or head of molten polymer, indicated as "B" in Fig. 6, is formed above the horizontal flange as shown.
W O 97/33841 PCT~US97/03012 The peripheral wall is adapted with a row of orifices 84 around its circumference, the orifices being positioned adjacent the radially outward end of the horizontal flange. As can be seen in Fig. 7, each orifice is in the shape of a "Y", with one arm leading to the molten glass "A", the other arrn leading to the molten polymer "B", and 5 the base leading to the exterior of the peripheral wall. The flows of both molten glass and ~ molten polymer join and emerge ~rom the orifice as a single bicomponent fiber 86 of glass and polymer.
Other spinner configurations can also be used to supply streams of molten glass and molten polymer to the spinner orifices.
The bicomponent fibers of this invention can be formed from many different kinds of glass and thermoplastic material. Usually the softening point of glass is significantly higher than the melting point of a thermoplastic material. Under ordinary circumstances, if molten thermoplastic material is exposed to the higher temperature of molten glass, there is a problem of thermal degradation of the thermoplastic material. It is 15 believed that the bicomponent fibers formed by the rotary process of this invention substantially avoid thermal degradation of the thermoplastic material. The molten bicomponent streams are formed, centrifuged and cooled so rapidly that the molten thermoplastic material is exposed to the higher temperature of the molten glass for only a fraction of a second. The spinner can be provided with an inert atmosphere or insulating 20 material between the molten glass and the molten thermoplastic material to further avoid any signif1cant thermal degradation.
Generally, however, the bicomponent fibers of this invention are formed from a low softening glass and a high melting thermoplastic material so that the two components have similar fiber forming temperatures. For purposes of this invention, the 25 glass will be characterized by the temperature at which its viscosity is 1000 poise, as measured according to ASTM C965. The thermoplastic material will be characterized by its melting point as determined using DSC (Differential Scannin~ Calorimetry). It is understood that use of the term "melting point" does not strictly apply to some classes of thermoplastic materials, specifically amorphous materials. In such cases, the term 30 "melting point" means the temperature at which the material softens and is easily flowable so that it can be fiberized, as known to persons skilled in the art.
WO 97/33841 PCTAUS97/03012Preferably the temperature at which the viscosity of the glass is 1000 poise is within about 200~C of the melting point of the thermoplastic material~ more preferably within about 1 50~C, and most preferably within about 1 00~C. The temperature at which the viscosity of the glass is 1000 poise is less than about 600~C, preferably less than about 5 550~C, more preferably less than about 500~C, more preferably from about 200~C to about 495~C, and most preferably from about 260~C to about 445~C. The melting point ofthe thermoplastic material is above about 140~C, preferably from about 200~C to about 345~C, and more preferably from about 260~C to about 345~C. The glass and thermoplastic material can be modifled to adjust these temperatures.
Preferred low softening glasses are high-borate glasses and high-phosphate glasses. The term "high-borate glass" means that the glass composition has a B2O3 content greater than about 8% by weight of the total glass composition. A particularly preferred high-borate glass has a composition by weight percent of from about 0% to about 10% SiO2, from about 0% to about 8% Al2O3, from about 70% to about 92% PbO, 15 and from about 8% to about 25% B2O3. The temperature at which the viscosity of a high-borate glass is 1000 poise is usually from about 300~C to about 500~C. Some examples of the compositions by weight% of suitable high-borate glasses, and the temperature at which their viscosity is 1000 poise, are shown below in Table I:
Table I
B2O3 9 7 19.6 9.6 18.6 10 9.9 SiO2 0.8 0.6 10.4 5 5 PbO 89.5 79.8 80 74.6 82 80.2 Al2O3 6.8 3 AlF3 4.9 T (~C) 427 494 538 497 431 399 The term "high-phosphate glass" means that the glass composition has a P2O5 content greater than about 20% by weight of the total glass composition. A
particularly ~-c;r~llcd high-phosphate glass has a composition by weight percent of from about 50% to about 80% P2Os, from about 10% to about 30% Na2O and K2O, from about 0% to about 30% PbO, from about 0% to about 7% Al2O3, and from about 0% to about 7 15% other oxides such as ZnO, MgO, CaO, SnO and BaO. The temperature at which the viscosity of a high-phosphate glass is 1000 poise is usually from about 200~C to about W O 97/33841 PCT~US97/03012 500~C. Some examples of the compositions by weight% of suitable high-phosphate gl~çs, and the temperature at which their viscosity is 1000 poise, are shown below in Table II:
Table II
P2O561.2 71.8 59.2 27.4 26 19 Na2O6.5 K2O 9.8 19.6 19 ZnO 4.3 2.1 4.1 PbO11.6 11.3 10.7 7.2 9.3 AlF36.6 6.5 6.4 SnO 37.8 30.8 25.8 S~2 24 35.9 45.9 T(~C)530 499 492 289 247 179 If desired or necessary, additives such as fluorides or other halides, 15 th~ m oxide or alkali oxides can be added to the glass to lower the tRmperature at which its viscosity is 1000 poise. A preferred low softening glass cont~ining fluorine is disclosed in U.S. ~at. No. 4,379,070 to Fick, and in Phys. & Chem. Glasses, Vol. 70, pp.
49-55, 1988. Other low softening ~ sçs, and mixtures of glasses, can also be used.
The thermoplastic material used for forming the mul~icomponent fibers 20 can be selected from a w;de variety of suitable thermoplastic materials known for use in m~king fibers. Preferred high melting thermoplastic materials are selected from the following polymers: poly(phenylene sulfide) ("PPS"), poly(ethylene terephthz~ e)("PET"), poly(butylene terephth~l~qte) ("PBT"), polycarbonate, polyamide, and mixtures thereof. Polyolefins and asphalt are also suitable but less preferred because they are 25 somewhat lower melting or so~~rPning. Other high melting thermoplastic materials, amorphous thermoplastic materials, and mixtures of thermoplastic materials, can also be used.
An advantage of the rotary process of this invention is that the viscosities of the molten glass and molten thermoplastic material are not required to be close to one 30 another. The two viscosities can be significantly different and the process still forms suitable multicomponent fibers. Usually the viscosity of molten glass is higher than the viscosity of a molten thermoplastic material. In a specific embodiment of this invention, W O 97/33841 PCTnJS97/03012 the viscosity of the glass, at the temperature of the peripheral wall of the spinner, is higher than that of the thermoplastic material by a factor within the range of from about 5 to about 1000, and usually from about 50 to about 500.
The bicomponent fibers of this invention have a very irregular, curvilinear 5 nature due to the difference in therrnal expansion coeff1cients of the glass and thermoplastic material. Such a curvilinear nature is particularly advantageous for giving the fibers excellent insulating properties when they are used in in~ ting materials or textiles. As the fiber cools, the thermoplastic material contracts at a faster rate than the glass. The result is stress upon the fiber, and to relieve the stress, the fiber must bend into l O a curve. Preferably the coefficient of thermal expansion of the thermoplastic material is higher than that of the glass by an amount greater than about 10 ppm/~C, more preferably greater than about 30 ppm~~C, more preferably greater than about 50 pprn/~C, and most preferably greater than about 70 ppm~~C. Usually the glass has a coefficient of thermal expansion from about 5 ppm~~C to about 30 ppm/~C, while the thermoplastic material is a 15 polymer having a coefficient of thermal expansion from about 80 ppm/~C to about 120 ppm/~C.
The bicomponent fibers made by the rotary process of this invention can be formed having a smaller diameter than bicomponent fibers made by a textile process.
This advantage is provided because the rotary process uses centrifugal force to attenuate 20 the fibers instead of relying on the mechanical ~tten~l~tion of the textile process.
Preferably the bicomponent fibers have an average outside diameter of from about 2 microns to about 50 microns, and more preferably from about 5 microns to about 40 microns.
Each of the bicomponent fibers of the present invention is composed of 25 glass and thermoplastic mzltPri~l. If one were to make a cross-section of an ideal bicomponent fiber, one half of the fiber would be glass and the other half would be thermoplastic m~tPri~l In reality, a wide range of proportions of the amounts of glass and thermoplastic material may exist in the fibers, or perhaps even over the length of an individual fiber. The pcrcentage of glass may vary within the range of from about 5% to 30 about 9S% by volume of the total fiber, with the remainder being thermoplastic mzltPri~
In general, a group of fibers such as a wool pack will have many different combinations of percentages of glass and thermoplastic material, including a small fraction of fibers that W O 97/33841 PCTrUS97/03012 are single component. The pl~r~llc;d composition of the bicomponent fibers will differ depending on the application. For some applications, preferably the bicomponent fibers comprise, by volume, from about 40% to about 60% glass and from about 40% to about 60% thermoplastic material.
Cross-section photographs of fibers can be obtained by mounting a bundle of fibers in epoxy with the fibers oriented in parallel as much as possible. The epoxy plug is then cross-sectioned and polished. The polished sample surface is then coated with a thin carbon layer to provide a conductive sample for analysis by ~c~nnin~ electron microscopy (SEM). The sample is then ç~ ned on the SEM using a backscattered-10 electron detector, which displays variations in average atomic number as a variation in the gray scale. For exarnple, this analysis reveals the presence of glass and polymer by a darker and lighter region on the cross-section of the fiber, and shows the interface of the glass and polymer.
As shown in Fig. 8, if the glass/polymer ratio is 50:50, the interface 88 15 between the glass 90 and the polymer 92 passes through the center 94 of the fiber cross-section. As shown in Fig. 9, where the molten polymer has a lower viscosity than the molten glass, the polymer 92 can somewhat bend around or wrap around the glass 90 so that the interface 88 becomes curved. This requires that the bicomponent glass and polymer fiber stream em~n~tin~ from the spinner be m~inf~ined at a temperature 20 sufficient to enable the low viscosity molten polymer to flow around the higher viscosity molten glass. Adjustments in the spinner operating parameters, such as hot air flow rate, blower ples~ule, and polymer or glass temperature, may be necessary to achieve the desired wrap of the low viscosity polymer.
As shown in Fig. 10, the lower viscosity polymer 92 has flowed almost all 25 the way around the higher viscosity glass 90. One way to quantify the extent to which the lower viscosity polymer flows around the higher viscosity glass is to measure the angle of wrap, such as the angle alpha shown in Fig. 10. In some cases the lower viscosity - polymer flows around the higher viscosity glass to forrn an angle alpha of at least 270 degrees, i.e., the lower viscosity polymer flows around the higher viscosity glass to an 30 extent that at least 270 degrees of the circumferential surface 96 of the bicomponent glass and polymer fiber is made up of the polymer.
CA 02246283 l998-08-l3 W O 97/33841 PCT~US97/03012 As shown in Fig. 11, under certain conditions the polymer 92 can flow all the way around the glass 90 so that the polymer encloses the glass to form a clz~ ing In that case, the entire circurnferential surface 96 (360 degrees~ of the bicomponent glass and polymer fiber is the polymer.
The method of the invention is not limited to bicomponent fibers, but rather includes other multicomponent fibers of glass and thermoplastic material such as the tricomponent fiber illustrated in Fig. 12. To form this tricomponent fiber, separate strearns of first and second molten polymers 97 and 98 and molten glass 99 are supplied to a rotating spinner having an orificed peripheral wall. The first and second molten 10 polymers and molten glass are m~int~ined separate until combined in the orifices. One method is to use a spinner having a single row of orifices like in Fig. 6, but where the area above the annular hori~ontal flange 82 is separated into alternate compartments like in Fig. 5. Thus, two streams could be fed into each orifice from above the flange while a third stream is fed into each orifice from below the flange. Other spinner structures can 15 also be used. The first and second molten polymers and molten glass are centrifuged through the orifices as a molten tricomponent stream, and the tricomponent stream is m~in~ined at a temperature sufficient to enable one of the lower viscosity polymers 97 to flow around at least the molten glass 99. Upon cooling of the tricomponent stream, a tricomponent fiber is forrned. Another method to form a tricomponent fiber is to form a 20 molten bicomponent stream of glass and a blend of two polymers, where the polymers have different physical properties so that they separate from one another upon cooling to form fibers. The multicomponent fibers can also include more than three components.
The above descriptions and comparisons of the physical properties of glass and thermoplastic material apply to each of the materials of a multicomponent fiber.2~ Bicomponent fibers in accordance with this invention include fibers in which the glass and the thermoplastic material are disposed in side by side relation with one another. The rotary Ll~d~d~llS described above usually forms such side by side bicomponent fibers. The bicomponent fibers of this invention also include fibers in which one of the glass and the thermoplastic material forms a core, while the other forms 30 a sheath surrounding the core. The rotary apparatus can be specially constructed by methods known in the art to form sheath and core bicomponent fibers. In general, such apparatus feeds one molten component through orifices which form a sheath, and feeds W O 97/33841 PCTrUS97/03012 the other molten component into the interior of the sheath to form a core. Combinations of different kinds of fibers can also be formed. The multicomponent fibers of the invention can also be shaped fibers, produced by shaping the orifice so that fibers are formed having a non-circular cross section. Methods of m~mlf~cturing shaped fibers are 5 disclosed in U.S. Patent Nos. 4,636,234 and 4,666,485 to Huey et al.
Bicomponent fibers of glass and polymer of this invention could be formed according to the following example. The glass used to make the fibers is a high-borate glass. The temperature at which the glass has a viscosity of 1000 poise is about 399~C.
The glass has a coefficient of thermal expansion of about 10 ppm/~C. The polymer used 10 to make the fibers is poly(phenylene sulfide). The polymer has a melting point of about 2~5~C and a coefficient of thermal expansion of about 100 ppm/~C. Separate streams of molten glass and molten polymer are supplied to the spinner illustrated in Figs. 2 and 3 having a temperature of about 360~C at the peripheral wall. At this temperature, the viscosity of the glass is about 5,600 poise and the viscosity of the polymer is about 3,000 15 poise. The spinner has a diameter of about 38 cm and is rotated to provide a radial acceleration of about 7,600 meters/second2. The spinner peripheral wall is adapted with 350 orifices. Bicomponent streams of molten glass and molten polymer are centrifuged through the orifices. The streams are cooled to make bicomponent glass and polymer fibers which are collected as a wool pack. The average outside diameter of the fibers is 20 about 25 microns.
The principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specif1cally explained and illustrated without departing from its spirit or scope.
INDUSTRIAL APPLICABILITY
The multicomponent fibers of this invention are useful in many applications including apparel products, thermal and acoustical insulation products, - filtration products, and as binders in composite materials.
Claims (20)
1. A method for making multicomponent fibers of glass and thermoplastic material comprising:
supplying molten glass and molten thermoplastic material to a rotating spinner (10,72) having an orificed peripheral wall (32,66,74);
centrifuging the molten glass (A,90,99) and molten thermoplastic material (B,92,97,98) through the orifices (56,70,84) as molten multicomponent streams of glass and thermoplastic material; and cooling the streams to make multicomponent fibers of glass and thermoplastic material .
supplying molten glass and molten thermoplastic material to a rotating spinner (10,72) having an orificed peripheral wall (32,66,74);
centrifuging the molten glass (A,90,99) and molten thermoplastic material (B,92,97,98) through the orifices (56,70,84) as molten multicomponent streams of glass and thermoplastic material; and cooling the streams to make multicomponent fibers of glass and thermoplastic material .
2. The method of Claim 1 in which the multicomponent fibers are bicomponent fibers (38,86) and the melting point of the thermoplastic material is within about 200°C of the temperature at which the viscosity of the glass is 1000 poise.
3. The method of Claim 1 in which the temperature at which the viscosity of the glass (A,90,99) is 1000 poise is less than about 600°C.
4. The method of Claim 3 in which the temperature at which the viscosity of the glass (A,90,99) is 1000 poise is from about 200°C to about 495°C.
5. The method of Claim 1 in which the glass (A,90,99) has a B2O3 content of greater than about 8% by weight of the total glass composition.
6. The method of Claim 1 in which the glass (A,90,99) has a P2O5 content of greater than about 20% by weight of the total glass composition.
7. The method of Claim 1 in which the thermoplastic material (B,92,97,98) has a melting point above about 140°C.
8. The method of Claim 7 in which the thermoplastic material (B,92,97,98) has a melting point from about 260°C to about 345°C.
9. The method of Claim 1 in which the thermoplastic material (B,92,97,98) is selected from the group consisting of poly(phenylene sulfide), poly(ethylene terephthalate), poly(butylene terephthalate), polycarbonate, polyamide, polyolefins, asphalt, and mixtures thereof.
10. The method of Claim 9 in which the thermoplastic material (B,92,97,98) is a polymer selected from the group consisting of poly(phenylene sulfide), poly(ethylene terephthalate), poly(butylene terephthalate), polycarbonate, polyamide, and mixtures thereof.
11. The method of Claim 1 in which the multicomponent fibers are bicomponent fibers (38, 86) and the coefficient of thermal expansion of the thermoplastic material (B,92,97,98) is higher than the coefficient of thermal expansion of the glass (A,90,99) by an amount greater than about 10 ppm/°C.
12. The method of Claim 1 in which the multicomponent fibers are bicomponent fibers (38,86) and the viscosity of the glass (A,90,99), at the temperature of the peripheral wall, is higher than said viscosity of the thermoplastic material(B,92,97,98) by a factor within the range of from about 5 to about 1000.
13. The method of Claim 1 in which the molten multicomponent streams are formed, centrifuged and cooled so as to avoid thermal degradation of the thermoplastic material (B,92,97,98) by contact with the molten glass(A,90,99).
14. Multicomponent fibers of glass (A,90,99) and thermoplastic material (B,92,97,98) comprising, by volume, from about 5% to about 95% glass and from about 5% to about 95% thermoplastic material.
15. The fibers of Claim 14 in which the melting point of the thermoplastic material (B,92,97,98) is within about 150°C of the temperature at which the viscosity of the glass (A,90,99) is 1000 poise.
16. The fibers of Claim 14 in which the temperature at which the viscosity of the glass (A,90,99) is 1000 poise is less than about 500°C.
17. The fibers of Claim 14 in which melting point of the polymer (B,92,97,98) is above about 140°C.
18. The fibers of Claim 14 in which the fibers are bicomponent fibers (38,86) having an average outside diameter of from about 5 microns to about 50 microns.
19. The fibers of Claim 14 in which the fibers are side by side bicomponent fibers.
20. The fibers of Claim 14 in which the fibers are tricomponent fibers.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US60887296A | 1996-02-29 | 1996-02-29 | |
| US08/608,872 | 1996-02-29 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2246283A1 true CA2246283A1 (en) | 1997-09-18 |
Family
ID=24438405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002246283A Abandoned CA2246283A1 (en) | 1996-02-29 | 1997-02-27 | Bicomponent glass and polymer fibers made by rotary process |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0883578A4 (en) |
| JP (1) | JP2000511976A (en) |
| KR (1) | KR19990087288A (en) |
| CN (1) | CN1212670A (en) |
| AU (1) | AU1976997A (en) |
| CA (1) | CA2246283A1 (en) |
| TW (1) | TW351733B (en) |
| WO (1) | WO1997033841A1 (en) |
| ZA (1) | ZA971728B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2828894B1 (en) * | 2001-08-24 | 2004-01-02 | Schappe Sa | CUT RESISTANT YARN, IN PARTICULAR FOR THE PRODUCTION OF PROTECTIVE CLOTHING |
| US20040180598A1 (en) * | 2001-09-06 | 2004-09-16 | Alain Yang | Liquid sorbent material |
| US20040161993A1 (en) * | 2001-09-06 | 2004-08-19 | Gary Tripp | Inorganic fiber insulation made from glass fibers and polymer bonding fibers |
| US6718100B2 (en) * | 2002-03-28 | 2004-04-06 | Milliken & Company | Fire resistant conduit insert for optical fiber cable |
| CN106435775A (en) * | 2016-11-11 | 2017-02-22 | 北京化工大学 | Wired and wireless temperature measurement combined centrifugal melt electrostatic spinning device |
| CN112481718B (en) * | 2020-11-25 | 2021-09-21 | 浙江炜烨晶体纤维有限公司 | Polycrystal mullite fiber filament throwing machine |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2998620A (en) * | 1958-06-09 | 1961-09-05 | Owens Corning Fiberglass Corp | Method and means for centrifuging curly fibers |
| US4379070A (en) | 1982-04-26 | 1983-04-05 | Corning Glass Works | Tin-phosphorus oxyfluoride glass containing aromatic organic compound |
| US4636234A (en) | 1984-12-03 | 1987-01-13 | Owens-Corning Fiberglas Corporation | Method and apparatus for making non-circular mineral fibers |
| US4666485A (en) | 1984-12-03 | 1987-05-19 | Owens-Corning Fiberglas Corporation | Method and apparatus for making tapered mineral and organic fibers |
| JPS63270812A (en) * | 1987-04-28 | 1988-11-08 | Nippon Ester Co Ltd | Hot-melt composite binder fiber |
| DK245488D0 (en) * | 1988-05-05 | 1988-05-05 | Danaklon As | SYNTHETIC FIBER AND PROCEDURES FOR PRODUCING THEREOF |
| US5474590A (en) * | 1993-11-05 | 1995-12-12 | Owens-Corning Fiberglas Technology, Inc. | Spinner for manufacturing dual-component fibers having an angled array of orifices |
-
1997
- 1997-02-27 CA CA002246283A patent/CA2246283A1/en not_active Abandoned
- 1997-02-27 KR KR1019980706690A patent/KR19990087288A/en not_active Application Discontinuation
- 1997-02-27 AU AU19769/97A patent/AU1976997A/en not_active Abandoned
- 1997-02-27 EP EP97907882A patent/EP0883578A4/en not_active Withdrawn
- 1997-02-27 TW TW086102444A patent/TW351733B/en active
- 1997-02-27 CN CN97192634A patent/CN1212670A/en active Pending
- 1997-02-27 JP JP09532625A patent/JP2000511976A/en active Pending
- 1997-02-27 WO PCT/US1997/003012 patent/WO1997033841A1/en not_active Application Discontinuation
- 1997-02-27 ZA ZA9701728A patent/ZA971728B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ZA971728B (en) | 1997-09-04 |
| EP0883578A1 (en) | 1998-12-16 |
| WO1997033841A1 (en) | 1997-09-18 |
| KR19990087288A (en) | 1999-12-27 |
| CN1212670A (en) | 1999-03-31 |
| AU1976997A (en) | 1997-10-01 |
| EP0883578A4 (en) | 1999-04-21 |
| TW351733B (en) | 1999-02-01 |
| JP2000511976A (en) | 2000-09-12 |
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