Liquid crystal polyarylester chopped fiber for conveyor belt covering layer and cutting equipment

Abstract

The invention provides a liquid crystal polyarylester chopped fiber for a conveyor belt covering layer, one end of the liquid crystal polyarylester chopped fiber is provided with an expansion part, and the invention further relates to chopped fiber cutting equipment which comprises a perforated plate and a heating plate which are horizontally arranged; a plurality of thread inlet holes are uniformly and densely distributed in the perforated plate, and a filament penetrates into each thread inlet hole from the lower side; a cutter is arranged on the upper side of the porous plate; when the heating plate gets close to the perforated plate, the ends of the filaments in the wire inlet holes are melted, and after the heating plate leaves the perforated plate, the ends of the filaments in the wire inlet holes are solidified and form expanded parts. When the chopped fiber disclosed by the invention is applied to the covering layer of the conveying belt, the tensile strength of the covering layer can be improved, and the granular expansion part can also reduce the rolling resistance during material conveying; chopped fibers are prepared through the cutting equipment which is simple in structural design, filaments are separated one by one through the perforated plate, and the situation that the chopped fibers are fused and adhered is avoided; and the expanded part is shaped by adopting the shaping groove and the shaping convex block.

Description

Technical Field

[0001] The invention belongs to the technical field of chopped fibers, and in particular relates to liquid crystal polyarylate chopped fibers for a conveyor belt covering layer and a cutting device. Background Art

[0002] Flame-retardant conveyor belts are widely used in operations such as coal mining. These conveyor belts generally use fabric or steel cord conveyor belts. Compared to steel cord conveyor belts, fabric conveyor belts are lighter, have lower production costs, are easier to repair and replace, are relatively easy to connect, and are safer to use. However, because the belt core is made of fabric fibers such as nylon, cotton, and polyarylate, it has lower strength and is less suitable for working conditions requiring high tensile strength. While steel cord conveyor belts have higher tensile strength, they are heavy and sometimes prone to longitudinal tearing. Furthermore, if the conveyor belt ignites, it cannot be disconnected, which can easily cause the fire to spread along the conveyor belt. If the tensile strength can be further improved, fabric conveyor belts will be a better alternative to steel cord conveyor belts. In some operating conditions where only steel cord conveyor belts can meet the requirements, increasing the tensile strength of the steel cord conveyor belt cover will undoubtedly reduce the occurrence of longitudinal tearing, extend the conveyor belt life, and improve production efficiency.

[0003] Adding reinforcing fibers to the covering material is an effective way to increase the overall performance of the covering (especially tensile strength). Among the reinforcing fibers that can be added, liquid crystal polyarylate fibers have great application potential. Liquid crystal polyarylate fiber is a type of synthetic fiber with ultra-high strength. Making liquid crystal polyarylate fiber into chopped fibers for conveyor belt coverings is a very effective method to improve the tensile strength and other properties of conveyor belt coverings. However, liquid crystal polyarylate chopped fibers are currently mainly used to prepare liquid crystal polyarylate films and reinforce hard materials. If liquid crystal polyarylate chopped fibers with advantages such as high tensile strength, high modulus (above 150 GPa), high toughness (high temperature resistance of 250°C during production), high temperature resistance, low moisture absorption (water absorption rate <0.1%), and strong dimensional stability can be applied to conveyor belt covering materials for coal mines and other minerals, then the strength and service life of the conveyor belts will inevitably be greatly improved. In addition, when added to the covering layer, due to the large steric hindrance effect between the amide bonds in the liquid crystal polyarylate fibers, it is difficult for them to form hydrogen bonds with other materials, resulting in poor fiber surface activity. This makes it difficult for the liquid crystal polyarylate fiber material to fully combine with the rubber component of the covering layer, which makes it difficult to fully utilize the material properties of the liquid crystal polyarylate chopped fibers in the covering rubber material.

[0004] At present, the main research direction is to make the liquid crystal polyarylate fiber easier to combine with the rubber material of the cover layer by modifying the surface of the liquid crystal polyarylate fiber. If the combination degree of the liquid crystal polyarylate chopped fiber and the rubber material of the cover layer can be improved by other ways, in addition to the modification process, the material properties of the liquid crystal polyarylate chopped fiber can be better played, and the performance of the cover layer can be further improved. SUMMARY

[0005] The purpose of the present application is to provide a kind of liquid crystal polyarylate chopped fiber for conveyor belt cover and cutting equipment.

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

[0007] A kind of liquid crystal polyarylate chopped fiber for conveyor belt cover, the chopped fiber is cut from liquid crystal polyarylate material filament, and the chopped fiber has an enlarged portion at one end.

[0008] Preferably, the top of the enlarged portion is flat or spherical.

[0009] A kind of cutting equipment for the chopped fiber of claim 1, the cutting equipment includes a perforated plate arranged horizontally and a heating plate arranged parallel to the top of the perforated plate; the perforated plate is uniformly covered with multiple rows of wire inlet hole groups, each row of wire inlet hole group contains multiple wire inlet holes matched with the diameter of the filament, and each wire inlet hole penetrates a filament from the lower side; the row spacing of each row of wire hole group is greater than 5mm, and the spacing between adjacent two wire inlet holes is not less than 2mm; a cutting knife is arranged on the upper side of the perforated plate; the working temperature of the heating plate is 300-380 DEG C; when the heating plate approaches the perforated plate, the end of the filament in the wire inlet hole is melted, and after the heating plate moves away from the perforated plate, the end of the filament in the wire inlet hole is solidified and forms an enlarged portion.

[0010] Preferably, the thickness of the perforated plate is not less than 3mm.

[0011] Preferably, the upper end of the wire inlet hole is treated by reaming to form a shaped recess with a conical or bowl-shaped bottom; the heating plate is provided with a shaped protrusion corresponding to the shaped recess; the shaped protrusion protrudes from the lower surface of the heating plate, and the lower end of the shaped protrusion is matched with the shaped recess in shape.

[0012] Preferably, when the heating plate moves downward, the lower end of the shaped protrusion is inserted into the shaped recess and quickly separates, so that the part of the fiber in the shaped recess is melted and then solidified immediately, thereby forming an enlarged portion shaped by the shaped recess at the upper end of the filament.

[0013] Preferably, the lower end of the shaped protrusion is flat.

[0014] Preferably, the lower end of the shaped protrusion is provided with a bowl-shaped recess for making the upper part of the enlarged structure spherical.

[0015] Preferably, it further comprises a wire feeding device for feeding the wire, the wire feeding device being arranged below the wire feeding hole; the wire feeding device comprising a plurality of pairs of rollers arranged in parallel, each pair of rollers clamping a row of filaments;

[0016] Preferably, after the heating plate is separated from the porous plate, the wire feeding device starts to feed the wire, and a pair of rollers rotate relative to each other to feed the filament upward so that the filament extends a certain distance from the wire feed hole. Then the cutter runs to cut off the part of the filament extending from the wire feed hole and collects it to form chopped fibers.

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

[0018] 1. When the liquid crystal polyarylate chopped fibers with an expanded portion at one end are in the rubber system of the covering layer, even if the fibers fail to fully bond with the rubber, the fixed point formed by the expanded portion of the dumbbell-shaped chopped fibers enables them to be relatively stable in the rubber system. When the conveyor belt bends and deforms at high speed during operation, the chopped fibers are relatively unlikely to separate from the rubber system and move relative to it, which plays a positive role in the tensile strength and service life of the covering layer.

[0019] 2. The chopped fibers are prepared by cutting equipment, and a porous plate with inlet holes is used to separate the filaments one by one, which effectively avoids the melting and adhesion of adjacent fibers during heating;

[0020] 3. Use shaping grooves and shaping protrusions to melt and shape one end of the chopped fibers; the expanded portion can increase the tensile strength, and after shaping, the expanded portion with a spherical and granular surface can play a role similar to that of reinforcing particles. Adding it to the covering material can reduce the rolling resistance when conveying materials. Moreover, due to the support and stabilization of the chopped fibers connected to the expanded portion, the expanded portion will not fall off as easily as ordinary inorganic particles used to reduce rolling resistance, and can better maintain the low rolling resistance effect of the covering layer and extend its service life.

[0021] 4. A pair of rollers are used to clamp the filament to fix it, and the rollers can also realize the wire feeding action when they rotate. The structure is simple and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of a short-cut fiber with an enlarged portion at one end.

[0023] Figure 2 The figure is a structural diagram of a cutting device.

[0024] Figure 3 A schematic diagram of the structure of a porous plate.

[0025] Figure 4 It is a structural schematic diagram of a shaping groove and a shaping protrusion.

[0026] The numbers in the figure are: chopped fibers 100, expanded portion 200, porous plate 1, heating plate 2, wire feed hole 3, filament 4, shaping groove 5, shaping protrusion 6, bowl-shaped groove 7, wire feeding device 8, roller 9, and cutter 10. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention through specific examples. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention.

[0028] Example 1

[0029] like Figure 1 As shown, a liquid crystal polyarylate chopped fiber 100 for a conveyor belt cover is cut from liquid crystal polyarylate filaments and has an enlarged portion 200 at one end. When the liquid crystal polyarylate chopped fiber with the enlarged portion 200 at one end is placed in the rubber system of the cover, even if the fiber fails to fully bond with the rubber, the enlarged portion 200 forms an anchor point, allowing the dumbbell-shaped chopped fiber 100 to remain relatively stable in the rubber system. This prevents the chopped fiber from detaching from the rubber system and moving relative to it when the conveyor belt bends and deforms at high speed during operation, thus positively impacting the tensile strength and service life of the cover. In addition, the top of the expanded part is a plane or a spherical surface. The expanded part 200, which has been shaped, has a spherical surface and is granular, can play a role similar to that of reinforcing particles (the expanded part on the surface of the covering layer can reduce the friction resistance of the covering layer to a certain extent). When added to the covering layer material, it can reduce the rolling resistance during material transportation and improve wear resistance. Moreover, due to the support and stabilization of the chopped fibers connected to the expanded part 200, the expanded part will not fall off as easily as ordinary ceramic particles, and can better maintain the low rolling resistance effect of the covering layer.

[0030] Example 2

[0031] like Figure 2-4As shown, a cutting device for the short-cut fibers according to claim 1, the cutting device comprises a horizontally arranged porous plate 1 and a heating plate 2 arranged parallel to the porous plate; the porous plate 1 is evenly and densely covered with multiple rows of wire feed hole groups, each row of wire feed hole groups contains multiple wire feed holes 3 adapted to the diameter of the filament, and each wire feed hole passes a filament 4 from the bottom; the row spacing of each row of wire feed hole groups is greater than 5 mm, and the spacing between two adjacent wire feed holes is not less than 2 mm; a cutter 10 is provided on the upper side of the porous plate 1; the working temperature of the heating plate is 300-380 ° C; when the heating plate 2 approaches the porous plate 1, the end of the filament in the wire feed hole (the part of the filament in the shaping groove) is melted, and after the heating plate 2 leaves the porous plate, the end of the filament in the wire feed hole 3 solidifies and forms an expanded portion. The initial melting temperature of different liquid crystal polyarylate materials is different and should be tested before production. Generally, it is appropriate to keep the temperature 20-50℃ higher than the initial melting temperature of the material. If the temperature is too high, the material will decompose and the molten material at the cut fiber section will not cool and solidify quickly, which may cause adhesion with other fibers.

[0032] The thickness of the porous plate 1 is not less than 3 mm. Sufficient thread inlet hole depth can effectively prevent the filament from falling out during production.

[0033] The upper end of the wire inlet hole 3 is expanded to form a conical or bowl-shaped shaped groove 5. The heating plate 2 is provided with a shaped projection 6 corresponding to the shaped groove. The shaped projection 6 protrudes from the lower surface of the heating plate, and the lower end of the shaped projection 6 is shaped to match the shaped groove 5. As the heating plate moves downward, the lower end of the shaped projection 6 inserts into the shaped groove 5 and quickly disengages (the insertion time varies depending on the actual situation). This causes the portion of fiber within the shaped groove 5 to melt and then immediately solidify, thereby forming an enlarged portion 200 at the upper end of the filament, which is shaped by the shaped groove.

[0034] like Figure 4 As shown, in this embodiment, the lower end of the shaping protrusion is provided with a bowl-shaped groove 7 for making the upper part of the expanded structure spherical, so that the expanded part processed in this way is closer to a circle.

[0035] It also includes a wire feeding device 8 for feeding the wire, which is arranged below the wire feeding hole; the wire feeding device includes a plurality of pairs of rollers 9 arranged in parallel, each pair of rollers clamping a row of filaments;

[0036] After the heating plate 2 is separated from the porous plate 1, the wire feeding device starts to feed the filaments, and a pair of rollers 9 rotate relative to each other to feed the filaments upward, so that the filaments 4 extend a certain distance from the wire feed hole 3. Then the cutter runs to cut off the part of the filament extending from the wire feed hole and collects it to form chopped fibers 100.

[0037] It should be pointed out that the cutting device of the present application can also be used for cutting other short fibers, but the working temperature of the heating plate needs to be adjusted.

[0038] The above embodiments are the preferred implementation methods of the present application, which are used to illustrate the present application, but the present application is not limited to the specific details in the above embodiments. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present application, which are all within the protection scope of the present application.

[0039] The above embodiments only exemplarily illustrate the principles and effects of the present application, but are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and category of the present application. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical thought disclosed by the present application should be covered by the claims of the present application.

Claims

1. A liquid crystal polyarylate chopped fiber for a conveyor belt cover, characterized in that: The chopped fibers are cut from liquid crystal polyarylate filaments, and one end of the chopped fibers has an expanded portion.

2. The liquid crystal polyarylate chopped fibers for conveyor belt covering according to claim 1, characterized in that: The top of the enlarged portion is a plane or a spherical surface.

3. A cutting device for the chopped fibers according to claim 1, characterized in that: The cutting equipment includes a horizontally arranged porous plate and a heating plate arranged parallel to the porous plate; the porous plate is evenly and densely covered with multiple rows of wire feed hole groups, each row of wire feed hole groups contains multiple wire feed holes adapted to the diameter of the filament, and each wire feed hole is used to insert a filament from the bottom; the row spacing of each row of wire feed hole groups is greater than 5 mm, and the spacing between two adjacent wire feed holes is not less than 2 mm; a cutter is provided on the upper side of the porous plate; the working temperature of the heating plate is 300-380°C; when the heating plate approaches the porous plate, the end of the filament in the wire feed hole is melted, and after the heating plate leaves the porous plate, the end of the filament in the wire feed hole solidifies and forms an expanded portion.

4. The cutting device according to claim 3, characterized in that The thickness of the porous plate is not less than 3 mm.

5. The cutting device according to claim 3, characterized in that: The upper end of the wire inlet hole is expanded to form a shaped groove with a conical or bowl-shaped bottom; a shaped protrusion is provided on the heating plate corresponding to the shaped groove; the shaped protrusion protrudes from the lower surface of the heating plate, and the shape of the lower end of the shaped protrusion is adapted to the shaped groove.

6. The cutting device according to claim 5, characterized in that When the heating plate moves downward, the lower end of the shaping protrusion is inserted into the shaping groove and quickly separated, so that part of the fiber in the shaping groove melts and then solidifies immediately, thereby forming an expanded part shaped by the shaping groove at the upper end of the filament.

7. The cutting device according to claim 6, characterized in that The lower end of the shaping protrusion is a plane.

8. The cutting device according to claim 6, characterized in that The lower end of the shaping protrusion is provided with a bowl-shaped groove for making the upper part of the expanded structure spherical.

9. The cutting device according to claim 3, characterized in that: It also includes a wire feeding device for feeding wire, which is arranged below the wire feeding hole; the wire feeding device includes several pairs of rollers arranged in parallel, and each pair of rollers clamps a row of filaments.

10. The cutting device according to claim 9, characterized in that After the heating plate is separated from the porous plate, the wire feeding device starts to feed the filaments. A pair of rollers rotate relative to each other, feeding the filaments upward so that the filaments extend a certain distance from the wire feed hole. Then the cutter runs to cut off the part of the filaments extending from the wire feed hole and collects it to form chopped fibers.

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