TW470791B - Process and apparatus for collecting continuous blow spun fibers - Google Patents

Abstract

The present invention provides a process and apparatus for blow spinning continuous fibers. The novel process utilizes a tensioning device to preclude slack in the fiber. The present invention also provides novel fiber products which utilize continuous fibers prepared by a blow spinning process.

Description

470791 _ Case No. 87118268_ Year Month Date __ V. Description of the invention (1) I. Background and summary of the invention A. Summary of the invention _ The present invention provides a high-strength, small-diameter wood pulp base for producing a continuous one-dimensional array Method and device for carbon fiber. Generally, the present invention provides a blow spinning method which results in a blow-spun product having the characteristics of the type of melt-spun product at the blow spinning speed. Therefore, the present invention improves product uniformity and production economy. Although the present invention is particularly useful for blown spinning fibers from carbon-containing pith, other uses will become apparent from the following disclosure. B. Background of the Invention Since blow spinning operations are well known in the art, they will only be summarized for discussion. A representative blow spinning method utilizes a spinnable substance, a drawn medium, normally a gas, and a spinneret containing fibers to form a capillary. During the spinning process, the fibers exit the capillary and are contacted by the fine media, which pulls or stretches each fiber, increasing its length while reducing its diameter. The quenching rate is also affected because the finely drawn medium is normally a gas' fiber. Generally, fibers produced by blow spinning are short discontinuous fibers with a length of less than two inches. In contrast, melt-spun fibers are usually continuous fibers with essentially infinite length. The normal fiber length of melt-spun fibers is selected by design and is not governed by the method of fiber production. In addition, the melt-spun fiber has a fineness uniformity superior to that of the blown-spun fiber. Several types of boards are available for blown spinning fibers. Generally, a blown spinneret is indicated by a method of directing the drawn gas into contact with the fibers. The two designs are ring and slot plate. In particular, in an annular plate, the fine gas is drawn out of an annular portion formed around each capillary 'and parallel to the fibers.

O: \ 55 \ 55268.ptc Page 4 470791 _Case No. 87118268_Year Month Day__ V. Description of the invention (2) flows. Thinning occurs due to the resistance of the gas to the fibers. In the slotted plate, the finely drawn gas exits the slot at either side of the plate tip that the fiber contacts at an angle. As determined by the plate geometry, the contact angle is optimized for the spinnable material to obtain the desired fiber characteristics. The invention is equally applicable to all types of blown spinnerets. A representative blow spinning method allows the spinning fibers to fall to a collecting surface after being drawn. Depending on the fiber composition, this method produces a short random array of two or three-dimensional batts. Fibers collected in this way may contain unwanted bends and kinks, resulting in lower fiber tensile strength. The main cause of fiber bending and kinking is believed to be the disturbance caused by the narrowing of the gas when the fiber is quenched. Those skilled in this art have recognized that the process of fiber collection is a key step in achieving high tensile strength fibers. The prior art method for collecting blown spinning fibers is collected in a three-dimensional random batt, which generally increases the number of bent and kinked fibers. The most recent U.S. Patent No. 5,6 4 8,0 41 states that the fibers are collected in a two-dimensional batt. However, a device for achieving a two-dimensional flocking pad requires an additional processing device and strict control of the drawing gas. As illustrated by the melt spinning method, manufacturers have long recognized that placing or collecting unidirectional fibers on, for example, a spindle or spool, will produce the final fiber characteristics. However, prior to the present invention, no device for this purpose was found in a blow spinning method. The present invention provides a device and method for collecting continuous blown spinning fibers, thereby overcoming the difficulties previously associated with blown spinning fibers. In addition, the method and apparatus of the present invention provide unidirectional collection of continuous fibers. The term " continuous fiber " as used herein means that the fiber has a substantially infinite length. Interruptions in continuous fiber length are usually intentional or due to manufacturing issues

O: \ 55 \ 55268.ptc Page 5 470791 _Case No. 87118268_Year Month and Day_ί ± _ 5. Explanation of the invention (3) happened. Moreover, the fibers produced by the present invention have improved fiber uniformity and tensile strength. Finally, the present invention provides a blow spinning method that produces a melt-spinning type product at the same rate as blow spinning. I. Summary of the Invention The present invention provides a device for blow spinning continuous infinitely long fibers. The novel device includes a blown spinneret, having at least one capillary tube for forming fibers, and a device for guiding a drawn gas, and the fiber contacts the fiber as it exits the capillary tube. The device also provides a device for placing tension on the fiber until it has been cured or quenched, i.e., cured. Furthermore, the present invention provides for the removal of gases and vapors from the fiber array or bundle, optionally before the fibers are collected in the receiving device. Furthermore, the present invention provides a method for producing a continuous blown spinning fiber. This innovative method prepares fibers by heating a spinnable substance and passing the substance through a spinning plate to form fibers. The fibers are thinned by drawing gas. After thinning, the method maintains tension in the fiber by a tensioning device, thereby eliminating sagging in the fiber. The continuous blown spinning fibers can be collected in a tensioning device or a subsequent device, such as a bobbin or winding device. The invention also provides a method for preparing a linear blown spinning fiber from a carbon-containing wood pulp. The novel method utilizes a device for maintaining tension in the fiber to eliminate sagging before the fiber is thermoset or quenched. The present invention further includes the step of collecting the fibers as a warp sheet or laterally moving the continuous filaments. If necessary, the present invention provides removal of gas and steam from the fibers before they are collected in the receiving device. Gases and vapors will preferably be removed by lateral flow ventilation added to the fibers before receiving the device. Finally, in cross-links such as (but not limited to) carbon, polyamides include nylon, polyesters such as " Dacron®

O: \ 55 \ 55268.ptc Page 6 470791 _Case No. 87118268_ Year Month Date__ V. Description of the invention (4) Acrylic, polyurethane 1 aims to include 'L ycr 〃, polyarylamines such as `` K The novel method will also be useful when spinning fibers with ev 1 ar® 中间 and crystalline materials such as mesophase pulp, solvated mesophase pulp and Zenite®. All trademarks are EIduPont de Nemours and Company. Registered trademark. In addition, when spinning wood pulp-based fibers, the present invention provides a continuous, direct, blown spinning fiber. The fibers are free of kinks, bends and other spin defects associated with blown spinning, reducing the mechanical properties of the fibers. Therefore, the present invention produces a fiber having significantly higher tensile strength. Furthermore, the present invention provides a unidirectional filament roving fabric prepared by transversing a continuous fiber bundle, a warp sheet, and a continuous fiber made by a self-blowing spinning method. I I I. Brief description of the drawings Figure 1 is a general illustration of the device of the invention. I V. Detailed description A. Device for blowing spinning and collecting fibers Please refer to the drawings, the present invention provides a blowing spinning and fiber collecting device 10. Apparatus 10 has a representative blown spinner, generally indicated as 20, a steam removal system 30, and a tensioning apparatus 40 or other suitable apparatus for maintaining tension in the spinning fibers. Blown spinnerets are well known in the art. In fact, as previously discussed, there are several well-known variations of blown spinnerets. The invention is suitable for use with all blown spinnerets. For additional information on the function of the blown spinning plate, please refer to the following references incorporated by reference: " Vibration and Stability in Melt Blowing Process ", Ind. Eng. C hem. Res., 1 9 9 3, 3 2, 3100-3111 R ao and Shambaugh;

O: \ 55 \ 55268.ptc Page 7 470791 _ Case No. 87118268_year month__; _ V. Description of the invention (5) " A Macroscopic View of Melt-Blowing Process for Producing Microfibers ", Ind. Eng. C he m. Res., 1988, 27, 2363-2372, Sh amba ugh; " Three-Dimensional

Temperature Field of Rectangular Array of Practical Air Jets ". Ind. Eng. Chem. Res., 1994, 33, 730-735, Mohammed and Shambaugh; " Superfine

Thermoplastic Fibers ", by van A. Wente, Industrial and Engineering Chemistry, Vo 1, 48, No, 8, August 1 9 5 6, pp. 1 342-46, and U.S. Patent No. 4,847, 125; 4, 380, 5 7 0; and 5, 2 8 6, 1 8 2. The optional steam removal system 30 of the present invention is particularly useful when the spinnable material contains volatile components, such as unreacted monomers or solvent components of solvated wood pulp. Solvent wood is successfully developed by the assignee of the present invention and is disclosed in U.S. Patents 5,259,947; 5,437,780; 5,501,788; and 5, 5 3 8, 6 2 No. 1, which is incorporated into the case by reference. In the preferred embodiment, the steam removal system 30 is positioned between the plate 20 and the tensioning device 40. The preferred steam removal system utilizes one or more blowers (not shown) or other devices to generate a lateral flow or movement of gas or air. Transverse flow ventilation Effectively removes hydrocarbon vapors or entrained components ’from the fiber bundle and helps to attach " off-bundle " filaments. Removal of volatile components from the fiber array or bundle prior to collection improves fiber handling. Finally, the device of the present invention includes a tensioning device 40. As shown in the figure, the device 40 can be as simple as a single bobbin or bobbin, and in continuous succession, the blown spinning fiber applies tension. Otherwise, before or after the device 40, additional spools, light, pins, hot plywood, etc. may be included to achieve cold stretching and thermosetting functions. 11 II · _ 11 1 O: \ 55 \ 55268.ptc Page 8 470791 Case No. 87118268 Month Amendment V. Description of the invention (6) The exact structure or device adopted is not critical to the present invention. Rather, the main focus is to provide a device for continuous, maintaining sufficient tension in the spun state of the fibers, removing sagging after the fibers are formed, and during collection. The fixed tension allows for continuous, aligned fibers in a linear array, which can be collected by any method known to those skilled in the art, such as warping or transversal continuous filament doffing. B. Method for blowing and spinning continuous linear fibers Please continue to refer to the drawings. The present invention provides a method for collecting and continuously blowing spinning fibers. As is well known in the art, various collection methods can produce warp sheets, traverse continuous fiber bundles, or other products. As previously mentioned, methods for blown spinning fibers are well known. However, while the benefits of collecting blown spinning fibers in a unidirectional manner are well known, it was not possible until the present invention. According to the method of the present invention, a spinnable substance is passed through a capillary of a blown spinning plate, thereby forming a blown spinning fiber. When the fiber exits the capillary tube in the spun state, it is contacted by the drawing gas. After drawing, the fibers are optionally passed through a steam removal system 30 to remove any unreacted monomers or solvents that may be entrained in the fiber array. Preferably, these materials are removed before the fibers are collected. This is especially true when preparing fibers from solvated wood, as any retained hydrocarbons will degrade the quality of the product obtained. The method of steam removal is preferably achieved by generating lateral flow suction. Preferably, the lateral flow suction will occur after the fibers are drawn and before the fibers are collected. Lateral flow suction can be generated by one or more blowers, compressors, or other suitable devices (not shown). The method of steam removal should not be related to the common lateral flow

O: \ 55 \ 55268.ptc Page 9 470791 _Case No. 87118268_ Year Month Day__ V. Description of the invention (7) The dynamic quenching step is confusing, which usually occurs in the melt spinning of fibers. The self-solvated wood pulp spinning fiber is rapidly quenched and heat-set near the part where the plate is dominated by rapid expansion and cooling of the drawn gas. Therefore, the fibers from the solvated pith have been quenched before the steam is removed. After the fibers are formed, the present invention utilizes a tensioning device 40 to maintain a firm and uniform force on the fibers. The tension placed on the fiber eliminates bending and possible kinking of the fiber and allows collection of continuous, infinitely long, blown spinning fibers. Furthermore, the fixed tension applied after the fibers are formed allows the fibers to be aligned in a linear array, which can be collected on a spool as warp sheets or traversed continuous fiber bundles. The effect of the other tensions on the fibers is different depending on the spinnable material; however, the other tensions do not act as the main tension. Instead, a finer gas is used for this function. Once the continuous fibers are aligned on a bobbin or other suitable collection device, the fibers can be cut for further processing. The removal from the spool will determine the characteristics of the final product. If a single cut is made along the length of the spool, the fiber can be removed as a standard unidirectional filament roving cloth with a length equal to the circumference of the spool. If short, straight and uniform length filaments are required, the fibers can be cut from the bobbin at a prescribed interval to achieve the desired filament length. Otherwise, as is well known to those skilled in the art, fibers can be processed on spools, cut to the desired length after removal or unwinding, and then stretched, warped, pidd 1 ed, or Any other desired way. In addition, before or after the continuous fiber is aligned by the tensioning device 40, it may include rollers, pins, hot plywood and other well-known devices to achieve cold or hot drawing and thermosetting functions. C. Continuous linear blown spinning of carbon fibers The present invention is particularly useful for spinning continuous fibers from mesophase pulp and solvated pulp

O: \ 55 \ 55268.ptc Page 10 470791 _Case No. 87118268_ Year Month Day__ 5. Description of the invention (8). U.S. Patent No. 5,6 4 8,0 41 discusses the difficulty of producing linear fibers from a solvated pith, especially a mesophase pith. As mentioned therein, the fibers are rapidly quenched in the area of the disturbance caused by the thinned gas, which can cause kinks and bends in the fibers. However, the use of the tensioner (40) of the present invention provides continuous, blown spinning fibers. Furthermore, the present invention increases the possibility of smaller final diameter products, while producing fibers with higher single filaments and composite strength conversion. Finally, the present invention allows larger diameters of the capillary of the spinneret, thereby reducing difficulties associated with small capillaries, such as plugging. Table 1 illustrates that the fibers of the present invention have improved tensile strength and have less change in diameter in the spun state than fibers prepared by prior art methods. The following test results are obtained from the solvated mesophase pulp pulp spinning of a single batch using the same blown spinneret. As shown in Table 1, the fiber of the present invention collected on the bobbin has a higher tensile strength and a smaller percentage change coefficient in the spinning state than the fiber collected in the batting mat. The coefficient of change in percent of fiber diameter (% CV) is the standard deviation divided by the average fiber diameter, which is shown as a percentage of a receipt group. A smaller% C V indicates an improvement in fiber fineness uniformity.

O: \ 55 \ 55268.ptc Page 11 470791 _ Case No. 87118268_ Year Month Day _ V. Description of the invention (9) Table 1 Variation coefficient collection fiber drawing in the spinning state method characteristic strength (Kps i) diameter% CV Knot 285 6.1 Knot 278 11.2 Straight line spool 378 3. 9 Straight line drawing 420 5.8 Those skilled in the art will consider the detailed description of this case or implement the invention disclosed in this case, and will understand other embodiments of the present invention . The foregoing detailed description is to be regarded as illustrative only, and the true scope and spirit of the present invention is indicated by the scope of the following patent applications.

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Claims (1)

470791 Day of P ~ _Case No. 87118268_ Year and Month 1 Article— & _ VI. Application for patent scope 1. A device for blown spinning continuous fiber includes: a blown spinning plate with at least one Capillary for forming fibers; please be careful about the content of the device for guiding the gas when the fiber exits the capillary; mechanical device for maintaining tension on the fiber after the fiber is drawn, the mechanical device is It is selected from the group consisting of bobbins, rolls and winding devices or any combination thereof. 2. The device according to item 1 of the scope of patent application, further comprising: a device for exhausting gas and steam from the fiber after the fiber is drawn. 3. The device according to item 1 of the patent application scope, wherein the device for maintaining tension in the fiber also provides a device for collecting the fiber. 4. A method for preparing a continuous linear blown spinning fiber from a mesophase pulp, the method comprising: passing the mesophase pulp into a capillary located in a blown spinning plate to form the mesophase pulp into fibers ; Contact the fiber with a drawing gas, thereby drawing the fiber; after drawing, by using a mechanical device selected from the group consisting of a bobbin, a roll and a winding device or any combination thereof, maintain sufficient tension in the fiber to eliminate the formation Sagging ° 5. The method of claim 4 in which the fiber is collected in a receiving device. 6. The method according to item 4 of the patent application, wherein the fiber is collected as a warp sheet or a continuous filament tow. 7. The method according to item 6 of the scope of patent application, wherein the warp sheet or transverse continuous filament doffing is separately treated to form a unidirectional filament roving fiber. 8. The method according to item 5 of the patent application, wherein it is collected at the receiving device O: \ 55 \ 55268.ptc Page 14 470791 _Case No. 87118268_ Year Month__ VI. Scope of patent application Before the fiber is removed, the gas and steam are removed from the fiber. 9. The method according to item 5 of the scope of patent application, wherein the gas and steam are removed by a lateral flow ventilation added to the fiber before receiving the device. 1 0. — A method for preparing a continuous in-line blown spinning fiber, comprising heating a spinnable substance to a temperature sufficient to allow the substance to flow, and then passing the substance to a spinning plate and passing through the plate Capillary tube, and when it exits the capillary tube, the fiber is brought into contact with at least one air flow, thereby drawing the fiber to form a continuous fiber. The improvement includes: after drawing the fiber, it is selected from a spool, a roller and a winding device. Or any combination thereof a mechanical tensioning device that maintains tension in the fiber. 11. The method according to item 10 of the scope of patent application, further comprising the step of collecting the fibers as a warp sheet or traverse continuous filament doffing in a winding device which receives the fibers from a self-tensioning device. 12. The method according to item 11 of the scope of patent application, including the step of removing gas and steam before collecting fibers. 1 3. The method according to item 11 of the patent application scope, wherein a lateral flow ventilation is applied to the fibers before the fibers are collected. 1 4. A traverse continuous fiber bundle comprising continuous fibers prepared by a blow spinning method. 1 5. The transverse continuous fiber bundle according to item 14 of the scope of patent application, wherein the fiber is made of carbon pith, polyamide, nylon, polyester, polypropylene, polyurethane, polyaramide and liquid crystal materials. Spinning by the group. O: \ 55 \ 55268.ptc Page 15