JPH05505855A - Apparatus and method for crimped fibers - Google Patents

Abstract

An apparatus and process for crimping and permanently heat setting a fiber or tow without imparting stress or tension on the fiber or tow comprising a conveying means (11) having a multiplicity of openings, means for supplying the fiber or tow to the conveying means (28), means for inserting (13) the fiber or tow (18) into the openings of the conveying means whereby the fiber is retained in a nonlinear shape in the openings without stress or tension, and a heating zone (17) through which the conveying means and fiber or tow pass for heat setting the fibers or tow.

Description

[Detailed description of the invention] Apparatus and method for crimped fibers The present invention crimps polymeric fibers without applying stress or tension to the fibers and permanently heats them. Relating to fixing methods and devices.

More specifically, the present invention applies stress or The polymeric precursor fibers are heat-treated without tension to form loops, coils, or relates to an apparatus and method for imparting a sinusoidal shape. The method and apparatus of the present invention It is relatively inexpensive and does not require pre-forming of the knitted fabric. The device of the invention has a large 40,000 to 320,000 fibers (40 Particularly suitable for the production of crimped fibers using a large number of precursor fibers, such as There is. The crimped fibers made according to the present invention exhibit hard dyeing uniformity when dyed.

The term "crimp" generally refers to the nonlinear properties of fibers or waveness. ), or more specifically, the waviness of a fiber expressed in crimp per unit length It is defined as Many synthetic fibers are used in the manufacture of carpet fabric, so for example The fibers are crimped or bent by thermal/mechanical techniques such as stuffer boxes. Geka is introduced. By preventing two or more fibers from being parallel to each other, Crimping of fibers is important in the manufacture of carpets, as it adds bulk to the fibers. is important. By crimping, the carpet tuft becomes larger with various benefits. Provides covering power, is more flexible, and has abrasion and scratch resistance. will be granted.

Crimp is also difficult to handle in stable processing due to its slipperiness. It is also useful in processing high modulus fibers.

The crimp done on many fibers using a stuffer box is mostly uniform. I can't say that. The fibers produced using stuffer box technology have a sharp V-shaped curve. It has wavy, irregular zigzag-shaped crimps with barbs or kinks. . The resulting irregularity of the crimp imparts non-uniform crimp to the fibers. But some studies of fibers have shown that the crimp is either regular or consistently irregular. be. Crimping of the fibers in the stuffer box causes the fibers to become crimped or non-linear. The fibers are passed through a uniformly heated chamber at a temperature sufficient to hold them in place. It is done by making The fibers are fed into the chamber by feeding rollers The fibers are pressed against the fibers already in the chamber, causing them to bend and shrink. A crimp occurs. Weighted tube attached to the top of the stuffer box (weighted tube) is the flow of fibers entering the stuffer box. The amount is adjusted. The frequency (crimps per unit length) and degree of fiber crimp (c rimp amplitude) is the weight of the tube as well as the supply to the take-up rollers. Adjusted by adjusting the speed of the rollers. This method of crimp fixation is Spanning techniques can be used to apply single fibers or tows with many fiber ends.

This crimp is generally characterized by having many sharp bends in the fiber.

In order to impart crimps to the fibers by this method and device, the fibers must undergo strong bending stress. must receive. During bending, two types of stress are applied to the fiber simultaneously. Ru. Tensile stresses are applied along the outer curve of the bend, while compressive stresses are applied along the outer curve of the bend. Acts on the inner part.

Recent research on the effect of crimp on polyester fibers shows that V-shaped crimp It is believed that strong bending can cause major fiber damage. Therefore, sharp Fibers that are strongly crimped in a V-shape have weakened mechanical properties and are less likely to develop during fiber handling. Due to the weakness of the fibers due to tensile and compressive stresses, they break easily. Like this Fibers are prone to breakage and spoilage due to the tensile and compressive stresses that occur during their handling. turn into.

In addition, the fibers crimped in the stuffer box are selectively It has a tendency to pick up dye and can cause optical artifacts. bending This is because the knee part protrudes towards the surface of the fibers, making it easier to poke into the eye. A new draft is generated. The inner part of the fiber bend contains more dye, so the fiber When viewed, the effect is a darker version. At the same time, the dye becomes darker in these tips. On the other hand, the remaining part of the fiber tends to be under-dyed and therefore The result will be a brighter colored manuscript.

The permanence of crimp after loading is determined by the fiber manufacturer or by the same manufacturer. Therefore, there are also differences between the various types (e.g. bright and semi-dual). . Since tension is unavoidably generated on the fiber during normal fiber processing, some crimping Losses will occur. This loss is the same for each spindle or for each yarn type. crimped fibers and their non-crimped fibers due to a decrease in the bulk factor. Because they look different, they look like different fibers. At the same time, crimping is being removed. , some fiber elongation occurs, which tends to adjust the fiber microstructure. . The well-organized microstructure takes in dye differently from fibers that do not elongate, so it is difficult to elongate. European Patent No. 0199567 (McCu 11 oug) H et al., October 29, 1990) have prepared stabilized polymeric fibers in the form of a knitted fabric. , a nonlinear carbon characterized by having physical properties obtained by heat treatment. Discloses a method for producing quality fiber. The knitted fabric is subjected to no stress or tension, A method of substantially irreversible heat setting is described. Nonlinear individual fibers, a In order to obtain a tow of fibers, it is necessary to knit and untie the footwear. . However, knitting and threading a knitted fabric to obtain nonlinear fibers is essentially a process of textile manufacturing. Increase costs.

U.S. Pat. No. 2,245,874 (Robinson) describes how fibers and their elastic limits The fibers are passed through cooling rollers under such conditions that they are bent and stretched beyond the A method of forming crimped fibers is disclosed. This kind of process is It can be used to produce untensioned nonlinear fibers with the physical properties of the invention. do not have.

U.S. Pat. No. 2,623,266 (Hemmi) describes sinusoidal or helical discloses a method for mechanically producing crimped fibers. The fibers are heated and the tune is The fibers are passed through a series of rods that impart torturous crimps to the fibers. but fiber is formed in a crimped and stretched state, i.e. under stress. .

Generally, the device of the invention includes a transfer member in the form of a belt having a plurality of apertures. It is characterized by having. The polymeric precursor fibers or fiber tows are fed to the transfer member. It is closed. The crimping device includes an opening in the transfer member that forces the fibers into a non-linear configuration. It is designed to be inserted into the mouth. The fibers placed in the openings in the transfer member are substantially For imparting temporary or permanent heat fixation to fibers in the absence of stress or tension. , and/or at least one heating zone at a temperature and rate sufficient to carbonize the fibers. be forced to move. Each heating zone supports one or more heating units; One of the heating units acts as an oxidation or stabilization zone for the fibers. . Other heating units heat the fibers substantially irreversibly or permanently in an inert atmosphere. Functions as a heat-fixing member.

More particularly, the present invention provides a transfer member having a flat surface and a plurality of apertures; a member for supplying at least I polymeric precursor fibers to the member; a member for transferring the fibers into the member; The crimping member inserted into the opening and the fiber pass through the transfer member to heat-set the fiber. cultivating a heated region without substantially imparting stress or tension to the transfer member or fibers; a polymeric material which maintains the fibers in a non-linear configuration in the aperture; Precursor fiber crimping and heat setting equipment.

The invention further provides at least one polymeric precursor fiber having a flat surface and an aperture. and inserting the fibers into at least two apertures in the transfer member to Bringing the fibers into a non-linear configuration without substantially imparting stress or tension to the fibers within the aperture and temporarily or permanently heat set the fibers in this stress-free condition. and/or through a heating zone at a temperature and speed sufficient to carbonize the fibers. and then cooling the fiber while in a non-linear configuration. A method of crimping and heat setting precursor fibers.

As used herein, the terms "polymer" and "polymeric precursor material" refer to Hawl ey’s Condensed Chemical Dict 1onary (11th edition, Van No5trand Rheinhold Company) Used for organic polymers as defined in Organic polymers are usually (1) Natural polymers such as cellulose, (2) Thermoplastic or thermoset elastics, etc. (3) semi-synthetic cellulose derivatives.

The term "fiber" as used herein refers to one or more fibers or filaments and fibers. It includes a plurality of fiber aggregates in the form of fiber tow.

As used herein, the term "oxidized" typically refers to 2 Used for fibers oxidized at temperatures below 50°C. In some cases, the fiber is lower It can also be oxidized by chemical oxidation at temperatures.

As used herein, the term "permanent heat setting" refers to When the stress on the fiber is released when it is stretched to a substantially linear configuration, A nonlinear carbonaceous fiber with irreversible properties that recovers its original nonlinear form. use Therefore, "permanently fixed" means that the fiber is in a substantially linear state. This clearly indicates the "reversible deflection" of the fiber when placed under such stress. Used for fibers with a certain degree of elasticity. When the stress is released, the fiber is in a stress-free state. and returns to a non-linear state. The term "reversible deflection" refers to stretching the fibers. It is a vine minimum limit, expressed as a ratio of 1.2:1, in which case it is relaxed. and the fiber is stretched to at least 1.2 times the length of the fiber under stress-free conditions. It represents the state of affairs.

The carbonaceous fibers can be stabilized with suitable polymeric precursor fibers, such as acrylic fibers. If so, it is typically produced using oxidation at a temperature of 250°C or less. Cheap The stabilized fibers are then relaxed and subjected to stress-free conditions and in an inert atmosphere. Heat treated for a sufficient time to cause a heat-induced thermosetting reaction, and the original weight is Additional cross-linking and/or cross-cyclization reactions occur between the combined chains.

The carbon fibers of the present invention can be classified into three groups depending on their usage and the environment in which they are used. Can be classified.

First of all, carbonaceous fibers are partially carbonized. The carbon content is 65% or more and 85% or less, and is electrically non-conductive and static. It has electric dissipation characteristics, that is, it cannot dissipate static electricity. Ru.

The term "electrically non-conductive" as used herein refers to individual 7 to 20 micron diameter Measure the tow of 6K (6000 fibers) of fibers consisting of 4X10@oichi The resistance value should be at least 100 mm/cm. The specific resistance of the carbon fiber is about 10-' cm/cm or more, which is specified in WO Publication No. i1!88102695. Calculated by measurement method.

If the fibers are stabilized and heat-set acrylic fibers, the nitrogen content should not exceed 18%. It becomes an electrically non-conductive fiber.

In the second group, carbonaceous fibers have low electrical conductivity, i.e. imperfect electrical conductivity. The carbon content is 65% or more and 85% or less. low conductivity When the tow is 6 or 4x10, it has a resistance of 4x10' ohm/cm. good Preferably, the carbonaceous fibers are derived from stabilized acrylic fibers and are 16 to 22 %, preferably from 16 to 18.8%. Such fibers are Effectively used in sound absorbing or heat insulating structures.

In the third group, the carbon content of the fibers is at least 85% and the nitrogen content is at least 85%. The amount is 10% or less. The fiber is characterized by high electrical conductivity. Immediately The fiber is essentially graphite and has an electrical resistance of 4XIO" ohms/c m or less. Correspondingly, the electrical resistivity of the fiber is less than or equal to 10-1 ohm/cm. . This fiber can be used as a furnace barrier or wherever electrical grounding or shielding is required. Useful in places.

The third group of carbonaceous fibers is made by heating the fibers to above 1000°C in a non-oxidizing atmosphere. By heating, it is also possible to impart electrical conductivity properties comparable to those of metal conductors. It is Noh. Electrical conductive properties include pitch (petroleum or coal tar), polyacetylene Acrylic material: For example, PANOX (registered trademark of Textiles) ) and GRAFIL-01 (E, 1. Dupont de Nemours & C.

copolymers of polyacrylonitrile, polyphenylene, salts such as Polyvinylidene chloride (SARAN, The Dow, registered trademark of Chemica 1 Company) ) and other selected starting materials.

The fibers may be made of any polymeric precursor material that is heat set in the apparatus of the invention. You can. Preferably, the polymeric precursor fibers used in the present invention are High-performance fibers such as Lil fiber (OFF), aramid fiber, FBI fiber, etc. . A preferred polymeric precursor fiber is a homopolymer of acrylonitrile, acrylonitrile. Copolymers of nitrile and terpolymers of acrylonitrile, which Polymers and terpolymers contain at least 85 mole percent acrylic units and other polymers. Contains up to 15 mole % of one or more monovinyl units copolymerized with a remer. the device is carbon as disclosed in the aforementioned European Patent Publication No. 0199567. Particularly suitable for producing quality fibers.

Preferably, the device of the invention does not require the steps of knitting and then unraveling the fibers. , used to produce carbonaceous fibers from polymeric precursor fibers. This device is a transfer member having a plurality of openings into which the fibers are inserted, applying tension and stress to the fibers; The present invention provides fibers with a non-linear shape, that is, crimped fibers, without any distortion. The transfer means also has tension The fibers are passed stress-free through a heating region having one or more heating units.

One heating unit may have a fiber oxidation zone or a stabilization zone. 100℃ A non-linear temporary fixation is performed on the fibers at temperatures between 250°C and 250°C. Separate heating unit The fibers are heat set virtually irreversibly under an inert atmosphere to achieve a carbon content of 65%. A heating member that supplies the above carbonaceous fibers may be grown. Like acrylic polymer Fibers derived from nitrogen-containing polymeric materials generally have a nitrogen content of 5 to 35 %, preferably 16 to 25%, more preferably 18 to 20% It is.

The following description, claims, preferred embodiments and drawings provide a more complete understanding of the invention. You will gain a better understanding. Please note that reference numbers used here for parts refer to each figure. It is consistent across the board.

Figure 1 is a perspective view of the crimping device of the present invention, and a portion thereof is a sectional view.

Figure 2 is an elevational view showing a cross section of the crimping device of Figure l.

Figure 3 is a side view of this device.

In the following description, specific terminology is used for clarity, and these terms do not apply to the present invention. have been chosen to illustrate this drawing solely for the purpose of illustrating the specific structure of the It does not define or limit the scope of the invention.

As shown in Figure 1, the device ft1O of the present invention has an opening formed in the feed roller 14. ．． 14' and extending through the enclosure or housing 12. Has a belt. Transfer belts can be wire grids, screens or bells with openings. The housing 12, which can take the form of a It may also have a cooling compartment. For example, the heating chamber 16 or where the tow 18 passes there are one or more heaters I7.17' and the cooling The chamber 20 is equipped with one or more cooling fans 21.

The fibers 18 first pass between a crimper and an apertured transfer belt, and are deposited on the crimper. is forced into the opening of the transfer belt 11 by a plurality of fingers 22 of the . After passing through the housing 12, the fiber 18 is wound by a take-up roller 26. taken. In operation, the fibers 18 are crimped into the opening of the transfer belt 11 by the crimping device 13. However, no force is applied to the fibers while passing through the heating chamber 16. The fibers are held together and no tension is applied to the fibers.

As seen in Figure 2, the crimping device 13 extends from a rigid reciprocating plate with a socket 15 It has a plurality of fingers 22 mounted so as to be slidable thereon. The fee The length of the finger 22 is such that it can be slid in or out from the socket and adjusted as desired. Adjustment is made by fixing the finger in position with the adjustment screw 27. can. By adjusting the length of the finger 22, the opening of the transfer belt can be adjusted. The depth of the loop of fiber stretched through the vine is adjusted. In this way, fiber 1 The form (degree of crimp) of 8 is determined by the length of the loop of fiber that is stretched into the opening. determined. Using a uniform finger 22 length will generally produce a sinusoidal morphology. It will be clear that it is possible to apply the fibers 18 to a uniform degree. do the same Therefore, if the lengths of the fingers 22 are made different and non-uniform, the fibers will be A sinusoidal morphology with corresponding heterogeneity can be imparted.

As shown in the figure, a flat reciprocating plate is rotatably mounted above the transfer belt. It is possible to replace it with a cylindrical drum-shaped member mounted on the turret. cylindrical member The rotation of the cylindrical member causes the fingers mounted on the outer circumferential surface of the contact and force the fibers into and through the openings of the transfer belt. The fu Fingers are usually tubular as shown, or relatively short, vertically extending rings. It may also be a block-like member. When the fingers take a rib-like form, the transfer belt The aperture has a corresponding square aperture so that the rib fits into the aperture.

In the side view of FIG. It enters the transfer belt that has been set up. Has adjustable fingers 22 for reciprocating movement The crimping device 13 inserts or pushes the fibers 18 into the openings of the transfer belt 11. , the fibers 18 are typically formed into a sinusoidal configuration. The fiber 18 is made into an opening. After insertion, the fiber retains its sinusoidal morphology and is free from any stress or tension. It is transferred into the housing 12 without being overlaid. The housing 12 is , having one or more heating chambers 16. The pre-chamber 16 is made of inert gas. It is full of resources. The carbonization of the fibers 18 is carried out using a radiant heater 17, a high energy source. or by other means known in the art.

The fibers 18 already heat set in a non-linear configuration within the chamber 16 are then preferably After being cooled in the chamber 20 by the cooling member 2I, it is carried out from the housing. and is wound up on rollers 26. Transfer belt II and rollers 26.28 The speed of the fibers placed on the transfer belt 11 or the heating chamber is synchronized. During its passage through the bar 16, the fibers are drawn out of the openings in the transfer belt; It is designed so that no stress or tension is applied.

The fiber is a stabilized or oxidized polyacrylonitrile fiber, When oxidized and/or carbonized, the oxidized fibers are exposed to nitrogen, argon, Temperatures between 250°C and 1500°C in a non-oxidizing atmosphere such as helium or hydrogen. heated to a certain degree. The heating zone may be a single-phase or multi-gradient furnace with a series of heating zones. There may be. Inert gas is supplied to the heating area through an opening 19 in the housing. or from various points along the fiber path through a conduit to the housing. may be entered.

The residence time of the fibers in the heating zone depends on the particular fiber used and the degree of heat setting desired. degree and the temperature (S) used.

Although the invention has been described within certain scope, this description is provided by way of example only. The details of the structure and the combination and arrangement of parts are not covered by the present invention. It could be changed without exceeding the scope.

FIG.3 international search report 噸+菅#内I=1噸＾--=,1-z-PCr/US90106314

Claims (10)

[Claims] 1. a transfer member having a flat surface and a plurality of apertures, the transfer member having at least one a member for supplying polymeric precursor fibers, the precursor fibers being inserted into openings in the transfer member; It has a crimping member and a heating area through which the fiber passes through the transfer member and heat-fixes the fiber. The transfer member moves the fibers non-linearly in the opening without applying stress or tension to the fibers. Crimping and maintaining a polymeric precursor fiber in shape Heat fixation device. 2. the transfer member has an apertured belt, wire grid or screen; The crimping member for inserting fibers into the opening of the feeding member may have a plurality of fingers or a long 2. The device of claim 1 having ribs. 3. The crimping member for inserting fibers into the opening of the transfer member has a rotatable cylindrical shape. drum and a plurality of fingers or long ribs extending from the peripheral surface of the cylindrical drum 3. The device of claim 1 or 2. 4. 4. A device according to claim 1, 2 or 3, wherein the fingers or ribs are adjustable in length. 5. The heating zone carbonizes the nonlinear precursor fiber at a temperature of 300°C to 1400°C. supplying an inert gas to the at least one heating unit and the heating region for 5. A device according to any one of claims 1 to 4, having a member. 6. The polymeric precursor fiber is an acrylonitrile homopolymer, an acrylonitrile homopolymer, or an acrylonitrile homopolymer. fibers selected from acrylonitrile copolymers and acrylonitrile terpolymers; Polymers and terpolymers contain at least 85 mole % acrylic units and another polymer. Claims containing up to 15 mol % of one or more monovinyl units copolymerized with The device according to any one of items 1 to 5. 7. having a member for supplying a plurality of fibers to the transfer member and a plurality of fiber winding members; The speeds of the transport member and the fiber supply and take-up member are synchronized. , an apparatus according to any one of claims 1 to 6. 8. Transferring at least one polymeric precursor fiber with a flat surface and an aperture member and inserting the fibers into at least two apertures of the transfer member within the apertures. Maintaining the fiber in a non-linear configuration without applying stress or tension to the fiber; The fibers are passed through a heating region under conditions free of heat and heated to a temperature at which the fibers are heat-set. , and then cooling the fiber while in a non-linear configuration. Crimping and heat fixing device for precursor fibers. 9. 300 to oxidize the precursor fibers and then pass through a heating zone to carbonize the fibers. ℃ to 1400℃ and supplying an inert gas to the heating area. Method of request 8. 10. The oxidized polymeric precursor fibers are placed in a transfer member with a flat surface and an aperture. supplying the fibers and inserting the fibers into at least two openings of the transfer member to transport the fibers within the closures. maintain the fiber in a non-linear configuration without applying stress or tension to the The nonlinear fiber is transferred to the heating region without applying stress to the fiber, and the nonlinear fiber is in this stress-free state. The fibers are heated at 300°C to 1400°C in an inert atmosphere to carbonize the fibers. Processes of heating to a high temperature to form nonlinear carbonaceous fibers without sharp bends or deformations and the carbonaceous fiber has a diameter of 4 to 2.0 microns and is larger than 1.2:1. Nonlinear, characterized by a high reversible deflection ratio and a carbon content greater than 65% Method for producing carbonaceous fiber.