Production method of insulating anti-static boneless sieve plate

Abstract

The invention relates to a production method of an insulating anti-static boneless sieve plate, and belongs to the technical field of sieve plates, and the insulating anti-static boneless sieve plate is prepared by extruding rigid thermoplastic polyurethane and then casting and molding polyurethane liquid uniformly added with natural graphite. The screen plate supporting framework does not contain a steel wire framework, extra targeted surface treatment is not needed, the strength and abrasion resistance of the screen plate can be guaranteed, the screen plate has enough rigidity and strength in the use period, and friction and sliding between the screen plate and the screen plate supporting framework caused by impact of materials and resonance between the screen plate and a screen box in the running process of the screen plate can be avoided; therefore, the abrasion of the sieve plate is intensified.

Description

Technical Field

[0001] The invention relates to the technical field of sieve plates, and in particular to a production method of an insulating antistatic boneless sieve plate. Background Art

[0002] Since the impact and wear resistance of steel wire woven screens to bulk materials are poor, workshops now use polyurethane screen surfaces. To ensure the strength and wear resistance of the screen plate, the screen plate uses a steel wire skeleton coated with polyurethane material. At present, the screen plate must contain a steel wire skeleton. Before pouring, the metal skeleton must be pretreated to ensure that the polyurethane screen plate has sufficient rigidity and strength during use. In addition, when the screen plate is installed, the tension of the screen plate is not enough. When the screen plate is in operation, the impact of the material and the resonance with the screen box cause friction and sliding between the screen plate and the screen plate support skeleton, thereby causing the screen plate to wear more severely. In summary, it is necessary to develop a production method for an insulated and anti-static boneless screen plate. Summary of the invention

[0003] In view of the problems existing in the above-mentioned prior art, the present invention aims to provide a method for producing an insulating antistatic boneless sieve plate.

[0004] A method for producing an insulating antistatic boneless sieve plate comprises the following steps: (1) extruding rigid thermoplastic polyurethane through an extruder, cooling and shaping, and hot-melt welding to obtain a thermoplastic polyurethane sieve; (2) placing the thermoplastic polyurethane sieve in a casting mold, using polyurethane liquid uniformly added with natural graphite to cast and mold, casting at normal pressure, vulcanizing, and post-vulcanizing to obtain a polyurethane cast sieve plate with high wear resistance.

[0005] Furthermore, in step (2), the mass ratio of natural graphite to the polyurethane liquid is 0.15% to 0.18%.

[0006] Furthermore, the natural graphite in step (2) is 325 mesh high carbon natural flake graphite.

[0007] Furthermore, in the step (1), the temperature of the first zone of the rigid thermoplastic polyurethane extruder is 160-170°C, the temperature of the second zone is 180-190°C, the temperature of the third zone is 190-200°C, and the head temperature is 200°C.

[0008] Furthermore, the vulcanization temperature in step (2) is 100-110°C and the time is 0.5-1h. Furthermore, the post-vulcanization temperature in step (2) is 100° C. to 110° C., and the time is 16 h to 24 h.

[0009] Furthermore, the Shore hardness of the thermoplastic polyurethane in step (1) is 65D to 82D.

[0010] Furthermore, in the step (2), the polyurethane liquid is prepared by cooling the dehydrated polytetramethylene glycol to 40°C to 60°C, adding the mixture into a reactor, adding toluene diisocyanate under stirring, reacting for 30min to 40min, heating the mixture to 75°C to 80°C, and continuing the reaction for 2h to 3h until the NCO content reaches 4.0% to 5.0%, vacuum degassing the mixture at 0.8kPa for 30min, and then uniformly mixing the mixture with 3,3'-dichloro-4,4'-diaminodiphenylmethane chain extender to obtain a chain extension coefficient of 0.9 to 0.95, thereby obtaining a polyurethane liquid.

[0011] Beneficial effects of the present invention: The production method of the insulating anti-static boneless sieve plate disclosed in the present invention adopts the method of extruding rigid thermoplastic polyurethane and then casting and molding the polyurethane liquid uniformly added with natural graphite. Since the sieve plate is made of polyurethane material as a whole and does not contain a steel wire skeleton, no additional targeted surface treatment is required, and the strength and wear resistance of the sieve plate can be guaranteed. It has sufficient rigidity and strength during use, and can avoid the defect of increased wear of the sieve plate caused by friction and sliding between the sieve plate and the sieve plate supporting skeleton due to the impact of materials and resonance with the screen box during operation. DETAILED DESCRIPTION

[0012] The present invention is described below with specific examples, but is not intended to be limiting of the present invention. Example 1

[0013] Raw materials: 325 mesh high carbon natural flake graphite from Pride New Materials; Tunhe PTMEG1000 polytetramethylene glycol, Juli Refining TDI-100 toluene diisocyanate; Huaibei Xingguang MOCA II powdered 3,3'-dichloro-4,4'-diaminodiphenylmethane; rigid thermoplastic polyurethane WHT-1170DA, Shore hardness 65D.

[0014] A method for producing an insulating antistatic boneless sieve plate comprises the following steps: (1) extruding a rigid thermoplastic polyurethane through an extruder, cooling and shaping, and hot-melt welding to obtain a thermoplastic polyurethane sieve, wherein the temperature of the first zone of the extruder is 160°C, the temperature of the second zone is 180°C, the temperature of the third zone is 190°C, and the temperature of the die head is 200°C; (2) the polyurethane liquid is dehydrated polytetramethylene glycol cooled to 40°C, added to a reactor, and toluene diisocyanate is added under stirring. After reacting for 30 minutes, the mixture is heated to 75°C and reacted for 2 hours until the NCO content reaches 4.0%. The mixture was vacuum degassed for 30 min at 0.8 kPa, and then mixed evenly with 3,3'-dichloro-4,4'-diaminodiphenylmethane chain extender with a chain extension coefficient of 0.9 to obtain polyurethane liquid. The mass proportion of natural graphite in the polyurethane liquid was 0.15%. A thermoplastic polyurethane screen was placed in the casting mold, and the polyurethane liquid uniformly added with natural graphite was cast and molded. The mixture was cast, vulcanized and post-vulcanized at normal pressure. The vulcanization temperature was 100°C for 0.5 h, and the post-vulcanization temperature was 100°C for 16 h to obtain a polyurethane casting sieve plate with high wear resistance. Example 2

[0015] Raw materials: 325 mesh high carbon natural flake graphite from Ruijiang Shunxin Materials; thermoplastic polyurethane; MOCA-Ⅱ type 3,3'-dichloro-4,4'-diaminodiphenylmethane, Jianfeng Chiyuan Chemical PTMEG1000 polytetramethylene glycol, Youmai TDI-100 toluene diisocyanate; rigid thermoplastic polyurethane WHT-M882H, Shore hardness 82D.

[0016] A method for producing an insulating antistatic boneless sieve plate comprises the following steps: (1) extruding a rigid thermoplastic polyurethane through an extruder, cooling and shaping, and hot-melt welding to obtain a thermoplastic polyurethane sieve, wherein the temperature of the first zone of the extruder is 170°C, the temperature of the second zone is 190°C, the temperature of the third zone is 200°C, and the temperature of the die head is 200°C; (2) the polyurethane liquid is dehydrated polytetramethylene glycol cooled to 60°C, added to a reactor, toluene diisocyanate is added under stirring, reacted for 40 minutes, heated to 80°C, and continued to react for 3 hours until the NCO content reaches 5.0%. The mixture was vacuum degassed for 30 min at 0.8 kPa, and then mixed evenly with 3,3'-dichloro-4,4'-diaminodiphenylmethane chain extender, with a chain extension coefficient of 0.95 to obtain polyurethane liquid. The mass proportion of natural graphite in the polyurethane liquid was 0.18%. A thermoplastic polyurethane screen was placed in the casting mold, and the polyurethane liquid uniformly added with natural graphite was cast and molded. The mixture was cast, vulcanized and post-vulcanized at normal pressure. The vulcanization temperature was 110°C for 1 h, and the post-vulcanization temperature was 110°C for 24 h to obtain a polyurethane casting sieve plate with high wear resistance.

[0017] The insulating antistatic boneless sieve plates of Examples 1 to 2 were tested for performance. The performance test results are shown in Table 1 Table 1 Performance test results of the insulating antistatic boneless sieve plate of Example 1 and Example 2

[0018] Note: Refer to GB / T33091-2016 polyurethane sieve plate.

Claims

1. A method for producing an insulating antistatic boneless sieve plate, characterized in that: The following steps are involved: (1) The rigid thermoplastic polyurethane is extruded through an extruder, cooled and shaped, and hot-melt welded to obtain a thermoplastic polyurethane screen. (2) The thermoplastic polyurethane screen is placed in a casting mold, and is cast and molded by using a polyurethane liquid uniformly added with natural graphite, and then cast, vulcanized, and post-vulcanized at normal pressure to obtain a polyurethane cast screen plate with high wear resistance.

2. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: In the step (2), the mass ratio of natural graphite to the polyurethane liquid is 0.15% to 0.18%.

3. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: The natural graphite in step (2) is 325 mesh high carbon natural flake graphite.

4. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: In the step (1), the temperature of the first zone of the rigid thermoplastic polyurethane extruder is 160-170°C, the temperature of the second zone is 180-190°C, the temperature of the third zone is 190-200°C, and the head temperature is 200°C.

5. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: The vulcanization temperature in step (2) is 100-110° C. and the vulcanization time is 0.5-1 h.

6. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: The post-vulcanization temperature in step (2) is 100° C. to 110° C., and the time is 16 h to 24 h.

7. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: The thermoplastic polyurethane in step (1) has a Shore hardness of 65D to 82D.

8. The method for producing an insulating antistatic boneless sieve plate according to claim 1, characterized in that: The polyurethane liquid in step (2) is prepared by cooling the dehydrated polytetramethylene glycol to 40°C to 60°C, adding the dehydrated polytetramethylene glycol to a reaction kettle, adding toluene diisocyanate under stirring, reacting for 30min to 40min, heating the dehydrated polytetramethylene glycol to 75°C to 80°C, and continuing the reaction for 2h to 3h until the NCO content reaches 4.0% to 5.0%, vacuum degassing for 30min at 0.8kPa, and then mixing the dehydrated polytetramethylene glycol with 3,3'-dichloro-4,4'-diaminodiphenylmethane chain extender to obtain a chain extension coefficient of 0.9 to 0.95, thereby obtaining the polyurethane liquid.

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