Liquid crystal polyarylester chopped fiber for reinforcing covering layer of conveying belt and fiber cutting equipment

Abstract

The invention provides a liquid crystal polyarylester chopped fiber for reinforcing a covering layer of a conveying belt, the two ends of the liquid crystal polyarylester chopped fiber are provided with expansion parts, and the invention further relates to chopped fiber cutting equipment which comprises a distributor plate and a hot cutter; a plurality of pay-off grooves are formed in the distributor plate, and a filament is arranged at the bottom of each pay-off groove; the hot cutter is arranged on the front side of the distributor plate; during cutting, the hot cutter moves downwards close to the front side face of the distributor plate so as to cut the portions, extending out of the pay-off grooves, of the filaments, the sections on the two sides of the section are melted and enlarged, and finally cut chopped fibers are in a dumbbell shape with the two ends expanded. When the chopped fiber is applied to the covering layer of the conveying belt, the tensile strength of the covering layer can be improved, and the service life is prolonged; chopped fibers are prepared through the cutting equipment which is simple in structural design, filaments are separated one by one through the distributor plate with the pay-off groove, and the situation that the chopped fibers are fused and adhered is avoided; and a hot cutter is adopted for low-speed cutting, so that fracture surfaces on the two sides of the fibers deform or expand.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of short-cut fibers, and particularly relates to a liquid crystal polyarylate short-cut fiber for reinforcing a conveyor belt cover layer and a fiber cutting device. BACKGROUND

[0002] Flame-retardant conveyor belts are widely used in coal mine production and other operations. Such conveyor belts generally adopt fabric core flame-retardant conveyor belts or steel cord core conveyor belts. Compared with steel cord core conveyor belts, fabric core flame-retardant conveyor belts have the advantages of light weight, low production cost, convenient maintenance and replacement, relatively easy joint, and safe use. However, due to the use of nylon fibers, cotton fibers, polyarylate fibers and other fabric fibers as the belt core, the strength is relatively low, and it is difficult to adapt to the working conditions with high tensile strength requirements. Although steel cord core flame-retardant conveyor belts have high tensile strength, they are heavy and may sometimes be longitudinally torn. Moreover, when the conveyor belt is ignited, it cannot be disconnected, which easily leads to the spread of fire along the conveyor belt. If the tensile strength can be further improved, fabric core conveyor belts will better replace steel cord core conveyor belts. For some working conditions that can only be handled by steel cord core conveyor belts, if the tensile strength of the cover layer of the steel cord core conveyor belt can be increased, the occurrence of longitudinal tearing and other situations can undoubtedly be reduced, the service life of the conveyor belt can be prolonged, and the production efficiency can be improved.

[0003] Liquid crystal polyarylate fiber (LCP) is a kind of synthetic fiber with ultra-high strength. Using liquid crystal polyarylate fiber to make short-cut fiber for the cover layer of a conveyor belt is an effective method to improve the tensile strength and other properties of the cover layer of the conveyor belt. Currently, liquid crystal polyarylate short-cut fiber is mainly used for preparing liquid crystal polyarylate film and reinforcing hard materials. If liquid crystal polyarylate short-cut fiber with the advantages of high tensile strength, high modulus, high toughness, and high temperature resistance can be applied to the cover layer material of the conveyor belt for coal mines and other mineral products, the strength and service life of the conveyor belt can certainly be improved. However, when added to the cover layer, the large steric hindrance effect between the amide bonds in the liquid crystal polyarylate fiber makes it difficult to form hydrogen bonds with other materials, resulting in poor surface activity of the fiber, and making it difficult for the liquid crystal polyarylate fiber material to fully combine with the rubber component of the cover layer. This leads to the difficulty in fully exerting the material properties of the liquid crystal polyarylate short-cut fiber in the rubber material of the cover layer.

[0004] Currently, the main research direction is to modify the surface of the liquid crystal polyarylate fiber to make it easier to combine with the rubber material of the cover layer. If the degree of combination of the liquid crystal polyarylate (short-cut) fiber and the rubber material of the cover layer can be improved through other means, in addition to the modification process, the material properties of the liquid crystal polyarylate short-cut fiber can undoubtedly be better exerted, and the performance of the cover layer can be further improved. SUMMARY

[0005] The present application aims to provide a liquid crystal polyarylate short fiber for reinforcing the cover layer of a conveyor belt and a fiber cutting device.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0007] A liquid crystal polyarylate short fiber for reinforcing the cover layer of a conveyor belt, the short fiber being cut from a liquid crystal polyarylate filament, and having an enlarged portion at both ends.

[0008] A cutting device for the short fiber, comprising a line dividing plate and a hot cutter; the upper part of the line dividing plate is uniformly provided with a plurality of vertically arranged wire grooves, the width of the wire groove is matched with the diameter of the filament, and the bottom of each wire groove is provided with a filament, and the front end of the filament is exposed from the wire groove; the hot cutter is arranged on the front side of the line dividing plate; during cutting, the hot cutter moves downward from the front side of the line dividing plate to cut the part of the filament that is exposed from the wire groove, and when the filament is cut by the hot cutter, the cross section on both sides of the cutting part is melted, and the cutting part is enlarged due to melting, which makes the short fiber cut finally have an enlarged dumbbell shape at both ends.

[0009] Preferably, the working temperature of the hot cutter is 300-380℃.

[0010] Preferably, the line dividing plate is heated by electricity, and the working temperature of the line dividing plate is 60-140℃.

[0011] Preferably, the cutting device further comprises a wire feeding device for feeding the filament, and the wire feeding device is arranged on the rear side of the line dividing plate, and the wire feeding device comprises a pair of rollers for clamping the filament.

[0012] Preferably, after one cutting is completed, the hot cutter moves upward to reset, the pair of rollers rotate relatively to feed the filament forward, so that the filament is exposed from the wire groove by a distance, and then the hot cutter is operated again to cut the part of the filament that is exposed from the wire hole, so as to obtain the short fiber with enlarged ends.

[0013] Preferably, the hot cutter moves downward at a speed of not more than 10cm / s during cutting.

[0014] Preferably, the hot cutter is subjected to blade edge passivation treatment.

[0015] Preferably, the distance between the wire grooves is not less than 1.2mm.

[0016] Preferably, the front side of the bottom of the wire groove is provided with a chamfer.

[0017] Compared with the prior art, the present application has at least the following advantages:

[0018] 1. The two ends of the liquid crystal polyarylate short fibers with bulging parts can form anchoring points when they are in the rubber system of the covering layer, which can make them stable in the rubber system even if the fibers fail to combine with the rubber. During the operation of the conveyor belt, even if the covering layer is deformed at high speed, the short fibers are not easy to move relatively by separating from the rubber system, which plays an important role in ensuring the tensile strength and service life of the covering layer.

[0019] 2. The short fibers are prepared by cutting equipment, and the long filaments are separated by the division plate with a wire slot, which can well avoid the situation of melting and sticking of adjacent fibers during heating.

[0020] 3. The slow cutting is performed by using a hot cutter, which can cleverly make the deformation or bulging of the fiber at both sides of the section greater than the diameter of the fiber due to melting, tool pressure, etc.

[0021] 4. The long filament is clamped by a pair of rollers to form fixation, and the rollers can also realize the wire feeding action during rotation, which has simple structure and strong practicality.

[0022] 5. The chamfer is processed at the front side of the bottom of the wire slot, and when the hot cutter moves downward to contact the long filament, the long filament can be partially pressed at the chamfer to some extent, which can more easily guide the regular deformation of the molten section when the long filament is broken, thereby improving the consistency of the bulging part of the short fiber. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of a short fiber with bulging parts at both ends.

[0024] Figure 2 It is a structural schematic diagram of a cutting equipment.

[0025] Figure 3 It is a structural schematic diagram of a division plate.

[0026] The reference numerals in the figure are: short fiber 100, bulging part 200, division plate 1, hot cutter 2, wire slot 3, chamfer 301, long filament 4, wire feeding device 5, roller 501. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be described in detail below through specific concrete examples, and those skilled in the art can easily understand other advantages and effects of the present application from the disclosure of the present specification. The present application can also be implemented or applied by means of other different specific embodiments, and various modifications or changes can be made to the details in the specification based on different viewpoints and applications without departing from the spirit of the present application.

[0028] Example 1

[0029] AsFigure 1 As shown, a liquid crystal polyarylate chopped fiber for reinforcing the cover layer of a conveyor belt is disclosed. The chopped fiber 100 is cut from liquid crystal polyarylate filaments, and each end of the chopped fiber has an enlarged portion 200. When the liquid crystal polyarylate chopped fiber with enlarged portions at both ends is in the rubber system of the cover layer, even if the fiber does not fully bond with the rubber, the fixation points formed by the two enlarged portions 200 of the dumbbell-shaped chopped fiber 100 are like two fists embedded in the material, allowing the chopped fiber to remain stably in the rubber system. During the operation of the conveyor belt, even if the cover layer undergoes high-speed bending deformation, the chopped fiber is not easily detached from the rubber system and will not move relative to it, thereby ensuring the stability of the tensile strength of the cover layer and extending its service life.

[0030] Example 2

[0031] like Figures 2-3 As shown, a cutting device for the chopped fibers includes a separating plate 1 and a hot cutting blade 2. The separating plate 1 has multiple vertically arranged feeding grooves 3 uniformly machined on its upper part. The width of each feeding groove 3 is adapted to the diameter of the filament. Each feeding groove 3 has a filament 4 at its bottom, with the front end of the filament 4 protruding from the feeding groove. It is worth noting that the separating plate 1 can be made higher (e.g., 1-1.5m) so that the feeding grooves 3 are at a higher position. This allows for a longer falling time when the chopped fibers 100 are cut, which is beneficial for the rapid solidification of the expanded portion. The hot cutting blade is located on the front side of the separating plate. During cutting, the hot cutting blade moves downwards along the front side of the separating plate to cut the portion of the filament protruding from the feeding groove. When the filament is cut by the hot cutting blade, the two sides of the cut surface melt, and the cut surface enlarges due to melting. This results in the chopped fibers 100 being ultimately cut into a dumbbell shape with enlarged ends.

[0032] The operating temperature of the hot cutting blade 2 is 300-380℃. The initial melting temperature of different liquid crystal polyarylate materials varies, and testing should be conducted before production. Generally, it is advisable to set the temperature 20-50℃ higher than the initial melting temperature of the material. If the temperature is too high, it will cause the material to decompose, and the molten material at the cut fiber cross-section will not be able to cool and solidify quickly, which may lead to adhesion to other fibers.

[0033] The splitter plate 1 is electrically heated, and its operating temperature is 60-140℃. Preheating the filaments with the splitter plate helps to ensure that the deformation at the fiber cross-section occurs fully.

[0034] It also includes a wire feeding device 5 for feeding filaments, which is located behind the wire separating plate and includes a pair of rollers 501 for clamping the filaments.

[0035] After one cut is completed, the hot cutting blade 2 moves up and resets, and the pair of rollers 501 rotate relative to each other to feed the filament forward, so that the filament 4 extends a distance out of the wire feeding groove. Then the hot cutting blade runs again to cut off the part of the filament that extends out of the wire feeding hole, and obtains short-cut fibers with bulging ends.

[0036] When the hot cutting blade 2 is cutting, its downward movement speed is no more than 10 cm / s; the hot cutting blade is treated with a blunted cutting edge. This can prolong the contact time between the hot cutting blade and the filament, increase the contact area, allow more heat to be transferred to the filament, and cause more deformation at the cut surface.

[0037] The spacing between the wire feeding grooves 3 shall not be less than 1.2 mm. If the spacing is too small, the fibers may stick together.

[0038] like Figure 3 As shown, the bottom front side of the wire feeding groove 3 is chamfered 301. When the hot cutting blade moves downward and contacts the filament, it can locally press the filament at the chamfer to a certain extent. When the filament breaks, it is easier to guide the regular deformation of the molten cross-section (for example, to make the swollen part flattened in a radial direction), thereby improving the consistency of the swollen part of the short fiber.

[0039] It is worth noting that the cutting device of the present invention can also be used for cutting other short fibers, but the working temperature of the separating plate and the hot cutting knife needs to be adjusted accordingly.

[0040] The above embodiments are preferred implementations of the present invention and are used to illustrate the present invention. However, the present invention is not limited to the specific details of the above embodiments. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0041] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A liquid crystalline polyarylate staple fiber for reinforcing a cover layer of a conveyor belt, characterized in that, The short fibers are cut from liquid crystal polyarylate material filaments, and the short fibers have bulging parts at both ends.

2. A cutting apparatus for the chopped fibers of claim 1, characterized in that, The cutting device comprises a line separating plate and a hot cutter; the upper part of the line separating plate is uniformly provided with a plurality of vertically arranged wire releasing grooves, the width of the wire releasing grooves is matched with the diameter of the filaments, the bottom of each wire releasing groove is provided with a filament, and the front end of the filament is exposed from the wire releasing groove; the hot cutter is arranged on the front side of the line separating plate; during cutting, the hot cutter moves downward from the front side of the line separating plate to cut the part of the filament that is exposed from the wire releasing groove, and when the filament is cut by the hot cutter, the cross section on both sides of the cut part is melted, and the cut part is enlarged due to melting, which makes the short fibers that are finally cut into dumbbell-shaped short fibers with bulging parts at both ends.

3. The cutting apparatus of claim 2, wherein, The working temperature of the hot cutter is 300-380℃.

4. The cutting apparatus of claim 3, wherein, The line separating plate is heated by electricity, and the working temperature of the line separating plate is 60-140℃.

5. The cutting apparatus of claim 2, wherein, The cutting device further comprises a wire feeding device for feeding the filaments, the wire feeding device is arranged on the rear side of the line separating plate, and the wire feeding device comprises a pair of rollers for clamping the filaments.

6. The cutting apparatus of claim 5, wherein, After one cutting is completed, the hot cutter moves upward to reset, the pair of rollers rotate relative to each other to feed the filaments forward, the filaments are extended from the wire releasing grooves by a distance, and then the hot cutter is operated again to cut the part of the filaments that is extended from the wire releasing grooves, thereby obtaining the short fibers with bulging parts at both ends.

7. The cutting apparatus of claim 6, wherein, During cutting, the hot cutter moves downward at a speed of not more than 10cm / s.

8. The cutting apparatus of claim 7, wherein, The hot cutter is subjected to blade edge passivation treatment.

9. The cutting apparatus of claim 2, wherein, The distance between the wire releasing grooves is not less than 1.2mm.

10. The cutting apparatus of claim 9, wherein, The front side of the bottom of the wire releasing groove is provided with a chamfer.

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