MXPA00004893A - Improved method and apparatus for forming migration free glass fiber packages - Google Patents

Abstract

Energy efficient process and apparatus are disclosed for forming migration free glass fiber packages composed of fibers (16) bearing substantially uniform coatings of size composition. Heated air from around the fiber forming bushing (12) is drawn into a chamber (56) through which the glass fibers (16) pass to cause the water or solvent in the applied size to be evaporated. The flow of heated air through the chamber (56) is regulated so as to obtain substantially uniform size application to the fibers (16).

Description

METHOD AND APPARATUS IMPROVED TO FORM FIBER PACKAGING. OF GLASS FREE OF MIGRATION TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION The present invention relates to the manufacture of continuous glass fibers via a fiber-forming sleeve. More particularly, it relates to the use of hot air around the fiber-forming sleeve to help dry the sizing composition applied to the fibers to provide improved fiberglass packages which are free of migration, while regulating the flow of hot air to obtain a substantially uniform application of the sizing composition to the fibers.

BACKGROUND OF THE INVENTION Fiberglass packages are commonly manufactured by discharging a plurality of molten glass streams from a hot sleeve, attenuating the plurality of glass flows in a plurality of fibers, by passing the fibers through an applicator to apply an aqueous sizing composition to the fibers, gathering the fibers prepared in a strand in a collection shoe, and winding the strand over a collet to produce a bundle of fiberglass. This package is then dried to evaporate the water from the aqueous sizing. However, both the manufacturers and the users of the fiberglass packages produced in this way are well aware that there are problems with such packages which are generally known in the art as "migration". The migration is visually observable as a discoloration of the fibers in the package. This results during the drying process when the water that migrates out of the package carries a portion of the sizing with it, and therefore deposits more sizing than usual on the outer periphery of the package and in several random places along the way . One form of the migration problem has been addressed by simply separating the outer layers of the package to remove the discolored fiber. This, of course, wastes a good amount of material and is not economical. In addition, the edges of the packets, such as when a Type 30® square edge package is formed, can also have this migration problem and, of course, can not always be separated. As a result, when such packages are used, there are periodic "cracks" of bleached material resulting from this occurrence of edge migration. Since, the users of such packages generally find this visual occurrence unsatisfactory "cracks", they have made attempts to dry the sizing on the fibers before winding them in a package. One such method for eliminating the migration problem is described in U.S. Patent No. 5,055,119, where a migration-free package is provided by drawing air circumferentially around the sleeve to a heat transfer chamber through which the fibers pass between the sleeve and the winder. The open end of the chamber is located under the hot sleeve and sufficiently close to it, so that the air that is being drawn into the chamber is heated by the hot sleeve. The hot air moves through the chamber in contact with the fibers to help dry the applied sizing, and is removed from the chamber in a location adjacent to the bottom of the chamber. The chamber extends below the sizing applicator and is "located essentially circumferentially around the fibers, so that hot air can evaporate any sizing fluid, ie water or solvent." However, although the above method provides an energy-efficient process to dry the sizing on the fiber before forming the fiber in a package, and, thus, significantly reduce, if not eliminate, the migration problem of sizing, some disadvantages have been noted in certain circumstances with respect to the uniformity of the size coating applied to the fibers., with the longer sleeves that are very common nowadays to produce a large number of simultaneous fibers, it has been determined that, due to the immense heat given by such sleeves, the unrestricted air flow to the hot transfer chamber gives as a result insufficient and non-uniform cooling through the fiber fan between the sleeve and the sizing applicator roller. In particular, the fibers at the outer edges of the fan are typically colder than those at the middle of the fan. As a result, larger amounts of sizing composition are applied to the fibers on the outer edges of the fan than it is applied to the fibers in the inner region of the fan. In addition, the fibers located in the inner portion of the fan can remain so hot that they do not receive or retain sufficient amounts of sizing composition. Accordingly, there is a need for means to control the flow of air through the chamber to achieve uniform and adequate cooling of the fiber across the width of the fiber fan, so as to capture sufficient and substantially uniform amounts of fiber material. Sizing of the sizing applicator roll. This need is satisfied by the invention described herein.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a modification to the apparatus and process described in U.S. Patent No. 5,055,119, the disclosure of which is expressly incorporated herein by reference, to ensure the uniform application of sufficient quantities of sizing material to fibers. of glass. In particular, the present invention provides means for controlling the air flow adjacent to the fibers to control the relative cooling of the fibers to ensure that all of the fibers across the fan are substantially at the same temperature at which they cross the application roller. right away. In this regard, the apparatus of the invention provides an enclosure through which the fibers pass as they emerge from the sleeve until they are assembled to be wound in a package. According to the present invention, the enclosure is divided into two chambers aligned longitudinally below the sizing application roll, one in which the fibers pass to be dried, and the other of which serves to derive the excess of hot air away from the fibers. In addition, a damper is placed in the enclosure above the shunt, so that the hot air passing through the enclosure in the front of the fiber fan can be diverted away from the fibers to the hot air bypass chamber for Control the amount of air that actually passes through the fibers through the drying chamber. Accordingly, after passing over the sizing application roll, the fibers and the regulated amount of hot air pass through a drying chamber before being gathered by the collecting shoe and wound up to form a package. Additionally, a window is provided on the rear of the enclosure above the sizing application roller (i.e., on the flange-shaped guard) to similarly control the amount of hot air entering the enclosure from behind the fan. fiber. By varying the size of the ventilation opening across the width of the fiber fan to allow more air to escape from the center of the fan than from the outer edges, a more uniform fiber temperature can be established through the fiber fan in the applicator. of sizing Through the combined use of the shock absorber and the window, it is possible to control the amount of hot air that comes in contact with the fibers as they pass through the enclosure between the sleeve and the winder to control the temperature of the fibers and increase the uniformity of the sizing application.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings. Figure 1 is an isometric view, partly cut away exemplifying an apparatus such as. contemplated for use in the practice of the present invention; Figure 2 is a simplified, schematic, right side elevation view of the apparatus of Figure 1.

DETAILED DESCRIPTION AND PREFERRED MODALITIES OF THE INVENTION Referring to the drawings, there is shown in general an apparatus for forming fiberglass packages which are fed by migration and which are composed of fibers containing substantially uniform sizing coatings. The illustrated apparatus represents the preferred technique and apparatus for practicing the invention using the heat of the sleeve and the fibers as the sole source of energy to dry the size applied to the glass fibers. Referring to the drawings, there is shown in general a sleeve member 12 of whose lower plate 14 the molten glass is discharged and formed into a plurality of fibers 16. The lower plate 14 of the sleeve can be "without tip" or can include the more conventional fiber-forming tips adjacent to its bottom (not shown). Additionally, it will be understood that when tips are employed, the sleeve 12 may also include flap-like protections (not shown) to cool the glass emitted from the bottom of the sleeve 14. Significantly, it will be noted that conventional pre-filled stems were not illustrated in the drawings. When practicing the present invention to stop the migration of an aqueous sizing the pre-filled decks are generally undesirable. According to conventional practice, a winder 20 attenuates the glass emanating from the bottom of the sleeve 14 to form fibers 16. The fibers 16 are gathered in a bundle or strand 18. This strand, with the aid of a longitudinal advancing mechanism 22 , is rolled into a nipper 24 to produce a final fiber package. Any conventional collection shoe 26 can be used to gather the fiber array 16 into a strand. Also in a conventional manner, the fibers 16 are brought into contact with a rotating cylindrical sizing applicator ^ 28. The sizing applicator 28 rotates in a passage (not shown) which contains the sizing. The applicator is rotatably driven by means of suitable drives 30 supported on a suitable support 32. The applicator 28 is generally enclosed within and supported rotatably by a housing 34. To achieve drying of the size on the fibers before are rolled in a package, there is a heat transfer or drying enclosure generally designated 36. The enclosure 36 receives hot air at a point above the applicator 28, and keeps the heat transfer enclosed in contact between the hot air and the fibers for a sufficient period of time so that the fibers of the rolled package are dried and free of migration. The enclosure 36, therefore, extends to a point sufficiently below the applicator 28 to allow such drying to be effected. An extension of several feet (meters), for example, of at least 3 feet (0.9144 meters) below the applicator 28 is typically required. The heat transfer enclosure may be held in place by any suitable structural support generally designated 38. The enclosure 36 may be viewed as including three portions, namely, an upper portion 40, a lower portion 47, and an intermediate portion 44, each of which are designed and supported in such a way as to allow the opening and easy access to the fibers 16 and the applicator 28.

The upper portion 40 includes a more upper opening, preferably a generally rectangular end 42 which is positioned below the heated sleeve 12. Generally, it is preferred that the uppermost open end portion 42 of the enclosure 36 be positioned approximately nine (22.86 cm) to approximately sixteen inches (40.64 cm) below the bottom of the sleeve 14, ie, the bottom surface of a "no-tip" sleeve or the bottoms of the tips when such a sleeve is used. The upper portion 40 generally proceeds forward and downwardly from the end 42 and includes a front face 41 and the rearwardly extending side panels 46. The uppermost most posterior portion 40 is preferably defined by a rim-shaped shield 48. The flange-shaped shield 48 includes a flat backward inclined surface 50 and forwardly extending sides 52. The back surface 50 and the front face 41 converge slightly towards each other. The flange-shaped shield 48 includes conventional means 54 for moving the flange-shaped shield forward and backward respectively. As shown in the drawings, the flange-shaped protection 48 is in its operative backward position. Additionally, the rear surface 50 of the rim-shaped shield 48 has a vent opening 51 therein, not shown, to allow some of the hot air to be drawn toward the top portion behind the fibers to leave the enclosure instead. of going through the enclosure with the fibers. Preferably, the opening 51 is equipped with an adjustable cover that allows the size and / or shape of the ventilation opening to be controlled. Furthermore, it is generally preferred that the vent opening and the cover interact to define a passage of a geometric configuration that allows more air to flow out of the central region of the fiber fan than at the side edges of the fan. For example, suitable passage configurations may include diamond, triangular and elliptical openings. The middle portion or the intermediate portion 44 of the enclosure 36 generally proceeds back and down from the upper portion 42. The front face and the side panels of the middle portion 44 are generally an extension of the front face of the side panels of the interior. upper portion 40. The housing of the applicator 34 generally functions as a portion of the rear wall for each of the upper portion 40 and the middle portion 44, and is arranged and constructed so that the applicator is brought into contact with the fan. converging fibers 16. Generally, the applicator 28 is preferably positioned from about 20 (50.8 cm) to about 30 inches (76.2 cm) from the bottom of the sleeve 14. The lower portion of the enclosure 47, like the upper portion 40 and the middle portion 44, is preferably rectangular in cross section. The lower portion 47 is divided along, i.e., vertically, by the wall 45 into two longitudinal chambers, the drying chamber 56 through which the fibers pass, and the air bypass chamber 58. The wall 45 it is oriented in the lower portion 47 so that its flat face is substantially parallel to the width of the fiber fan, and is joined along its side edges to the sides of the enclosure by welding or other suitable means. Accordingly, the drying chamber 56 is positioned circumferentially around the glass fibers 16. The rear wall 60 of the drying chamber 56 includes an air outlet passage 62 near its bottom. Means are provided for removing air from the chamber and a duct 64 attached to the negative pressure side of the suitable air pump or air blower (not shown) is included. The duct 64 is in fluid communication with an adapter portion 66 which serves to provide fluid communication between the duct 64 and the internal portions of the chamber 56. If desired, a suitable slide gate (not shown) can be employed with either the duct or the adapter to control the air flow. The lower portion of the drying chamber 56 can also include a movable sliding gate 68 which controls the opening through which the fibers flow en route to the collection shoe 26. This sliding gate can also be used to help control the amount of air drawn towards the upper end 42. At the top of the wall 45, and attached thereto, is a damper 43 which controls the amount of hot air passing through the fibers through the drying chamber 56, or which is directed through the air bypass chamber 58. The damper 43 is rotatably connected to the wall 45 along its upper edge, so that it can be rotated towards the fiber array to derive more hot air away from the fibers and towards the bypass chamber, or spin away from the fibers to allow more hot air to pass through the drying chamber with the fibers. The damper 43 preferably has means extending out of the walls of the enclosure 36 to allow adjustment of the positioning of the rotary damper. Preferably, the adjustment means are equipped with a fixed stop which prevents the shock absorber from coming into contact with the fiber fan. Further, the damper is preferably of a size and is positioned such that when it is placed closer to the fiber fan, its upper edge is adjacent to the sizing application roll, so that, in combination with the ventilation opening on top of the Sizing application roller, effectively controls the amount of hot air passing through the drying chamber 56. The front face 57 of the bypass chamber 58 is preferably equipped with spray nozzles or jets 49 in fluid communication with a water supply (not shown) for spraying water into the chamber to cool the air passing through it. Additionally, the bottom of the bypass chamber 58 is preferably open to allow air passing therethrough to exit the fiber forming environment. It is generally recommended that the unit have a capacity to move 50 to 200 cfm (1.4 to 5.6 m3 / min) of air to a glass production of 60 pounds (27.22 kg) and approximately 100 to 500 cfm (2.8 a 14 mVmin) at a production of 200 pounds per hour (25.18 g / s). However, for large sleeves that have outputs of 200 (25.18) up to more than 300 (37.77) pounds per hour (g / s), it has been found that high air flow rates can have a negative impact on the application of sizing due to the immense heat transported by the air under such sleeves.As a result, the ventilation opening and the damper in the apparatus of the invention allow the regulation of the flow of air around the applicator and through the drying chamber to improve the application of fiber sizing In this way, according to the invention, it will be evident that the ambient air in the plant circumferentially around the sleeve flows under the lower wall 14 towards the upper open end 42 of the enclosure 36. Excess hot air admitted into the enclosure 36 can be ventilated through the ventilation opening 51 and / or diverted away from the fiber by the damper 43. The remaining air proceeds down through the drying chamber 56 with the fibers and is removed adjacent the bottom of the drying chamber through the conduit 64. In this manner, the fluid, either in solvent form in the preferred embodiment, and It evaporates from the aqueous fibers of an aqueous slurry and is removed through the duct 64. The package formed by the coiled strand 18 sobr. the clamp holder 24 will be completely dry and free of migration problems. The size fluid applied to the fibers according to the invention may contain an organic solvent or water. As indicated; the maximum benefit of the present invention is obtained when a water-based sizing is used. Such sizing compositions are well known in the art. Water-based sizing typically includes from about 93 to about; 96 or 9% of agüe with the rest of the sizing comprising several sizing constituents which may vary depending on the application. In general, the constituents may include one or more film formers, such as, for example, an epoxy, lubricants, surfactants, for example nonionic, cationic and anionic surfactants, thickeners and coupling agents. Typically the sizing applied will provide a water content of about at least about 6% to about the order of about 12 or 13%. Better results have been obtained using a water content in the order of about 10% and completely drying the fibers, i.e. drying them at a moisture content of less than about 0.02% water. This eliminates the migration. A preferred aqueous sizing composition for use in the apparatus and process of the invention comprises one or more heteropolysaccharides, in addition to standard coupling agents, lubricants and film formers of conventional aqueous sizing. The inclusion of heteropolysaccharide in the sizing provides better uniformity of application under high temperature conditions. Such sizing composition is described in greater detail in the copending US patent application filed at the same time as the present one, the description of which is expressly incorporated herein by reference. The preferred heteropolysaccharide is insensitive to heat over a wide temperature range and is soluble in cold water. In addition, the preferred heteropolysaccharide should be selected so as not to have negative effects on properties such as burst strength, cyclic fatigue or tensile strength. It should also have a viscosity of about 200 to about 500 cps in the temperature range of about 60 ° F (16 ° C) to approximately 160 ° F (71 ° C). A heteropolysaccharide is a polysaccharide gum. A particularly preferred polysaccharide gum is rhamsan gum such as Kelco Kl A112 obtained from The NutraSweet Kelco Company, San Diego, CA. Starches may be added in the range of about 0.001% to about 3.0%, more preferably in a range of about 0.05 to about 0.5%. Preferably, the starches are added in an amount of about 0.05% to about 0.25%, with 0.25% being most preferred. The preferred coupling agent should be a liquid at room temperature. Suitable coupling agents include organofunctional silanes, such as 3-glycidoxypropyltrimethoxy silane. Preferred coupling agents for use in the invention are 3-aminopropyltriethoxy silane and 3-methacryloxy-propyltrimethoxy silane commercially available from OSi Specialties of Witco sold under the trade designations of A-1100 and A174, respectively. Preferably, the organofunctional silanes are used in an amount of about 0.10% to about 2.00% of the sizing composition. Film formers useful in the invention include film formers which are water-based low molecular weight epoxy emulsions. For example, a suitable film former is an epoxy emulsion such as AD502 obtained from Owens-Corning. One or more lubricants may be used in the invention. Useful lubricants include those that are cationic or non-ionic. For example, suitable lubricants include MS-8 obtained from Henkel Corp., Trylube 7607 obtained from Henkel Corp., and PVP-K-90 obtained from GAF. The size of the present invention can be applied at temperatures ranging from about 60 ° F (16 ° C) to approximately 160 ° F (71 ° C). Preferably, a range of about 70 ° F is applied (21 ° C) at 100 ° F (38 ° C); and in a particularly preferred embodiment, the sizing is applied at 80 ° F (27 ° C). The most preferred sizing is applied at a temperature less than 180 ° F (82 ° C). Sizing can be applied at viscosities ranging from 50 to 1000 cps. Preferably the sizing is applied in the range of 200 to 500 cps. In a particularly preferred embodiment, the sizing is applied at a viscosity of about 380 cps at 27 ° C. The viscosity is given in cps as measured by a Brookfield viscometer using a number 31 spindle. In addition to the sizing components mentioned above, other components normally added to glass fiber sizing compositions may also be present. For example, the sizing composition of the invention may contain antistatic agents, crosslinking or hardening agents, antioxidants, cationic lubricants to reduce crimped or broken filaments, nonionic lubricants, nucleating agents or small amounts of pigment, etc. An example of a crosslinking agent would be bis-silane. An exemplary heteropolysaccharide sizing composition which can be used in combination with the apparatus of the invention to improve the uniformity of application of sizing at high temperature is that set forth below.

Example 1 The following sizing was prepared and designated "A" % [By weight or relative amount?] AD502 (epoxy emulsion, '5.00% Arctic acid 0.85 A174 (silane) 1.00 A1100 (silane) 0.25 S-8 (lubricant) 1.00 Trylube 7607 (lubricant) 0.25 PVP-K-90 (lubricant) 0.25 Deionized water 91.40 To the previous composition 0.25% heteropolysaccharide Kelko K1AII2 was added to make the formulation "B". Each formula was then tested to determine the viscosity at various temperatures. The viscosity measurement was made after the sample had been at a temperature for 30 minutes. The results are found in Table I below.

Table I Formula A (without B (with 0.25% starch) of starch) Viscosity in cps after 30 minutes at various ambient temperatures 100 ° F (38 ° C) 440 230 120 ° F (49 ° C) 360 323 140 ° F (60 ° C) 277 315 160 ° F (7i ° C) 168 312 180 ° F (82 ° C) 57 369 It is noted that in relation to this date, the best method known by the request and for washing the practice said invention, is what is clear from the present description of the invention.

Claims (5)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. An apparatus for drying sizing compositions deposited on a fan of attenuated fibers from a flow of molten glass emerging from a heated sleeve before the fibers are gathered into a strand and wound to form a package, the apparatus is characterized in that it comprises: (a) an enclosure through which the fibers pass, comprised of portions of the front, rear and side wall, placed under the sleeve and sufficiently separated therefrom so that the hot air around the sleeve is drawn into the enclosure and passed to its interior. through with the fibers; (b) a sizing applicator mounted adjacent the rear wall portion for applying a sizing composition to the fiber fan that passes through the enclosure; (c) a vent opening in the rear wall portion above the sizing applicator to allow some of the hot air to leave the enclosure; (d) a shunt placed in the enclosure below the sizing applicator to form a first and second longitudinal chambers in the enclosure, where the fibers pass through the first chamber; and (e) a damper rotatably attached to the shunt at its end adjacent to the sizing applicator to control the relative amounts of hot air passing through the first and second chambers. The apparatus according to claim 1, characterized in that the ventilation opening allows more air to flow into the enclosure of the center of the fiber fan than at the side edges of the fiber fan. The apparatus according to claim 1, characterized in that the ventilation opening is equipped with an adjustable closure to regulate the size of the opening. The apparatus according to claim 1, characterized in that the applicator forms a portion of the rear wall of the closure. The apparatus according to claim 1, characterized in that the second chamber has spray means mounted on the walls thereof to allow water to be sprayed into the chamber to cool the hot air passing through it.