A method for producing steel wire embedded in polyurethane screen

Abstract

This invention provides a method for producing a steel wire embedded polyurethane screen. Belonging to the field of polyurethane screen technology, the method involves extruding, cross-linking, and expanding polyurethane heat-shrinkable tubing, then embedding steel wires into the tubing, and continuing to weave or weld the screen. Finally, heat shrinkage is used to coat the steel wires with polyurethane, resulting in a steel wire embedded polyurethane (TPU) screen. This screen surface possesses advantages such as high elongation, good wear resistance, high tensile strength and tear resistance, and high open area. It also offers advantages such as long service life, good screening permeability, strong self-cleaning properties, high screening efficiency, light weight, easy installation, convenient maintenance, low noise, and strong adaptability. The aforementioned steel wire embedded polyurethane screen is a flexible screen surface similar to a metal wire woven screen surface. It consists of steel wire screen bars and a wear-resistant cross-linked TPU heat-shrinkable coating on the surface of the steel wires. The screen bars are arranged in a cross pattern through weaving or welding.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane screen technology, specifically relating to a production method of embedding steel wire into a polyurethane screen. Background Technology

[0002] Currently, most polyurethane screens in my country are manufactured using TDI-type cast polyurethane elastomers, with another portion using MDI-based casting. The prepolymers used are mostly synthesized in-house. However, this system presents several problems in its application: high processing difficulty, demanding casting equipment, and requiring a long vulcanization period of over a day, resulting in low production efficiency. Furthermore, it is only suitable for producing polyurethane screens with steel plate frames, not for producing polyurethane screens with embedded steel wire. With the development of my country's steel industry, iron ore beneficiation plants have undergone large-scale technological upgrades to improve quality and reduce impurities. The fine screening and regrinding process has widely adopted electromagnetic vibrating high-frequency fine screens, replacing the previously used fixed nylon fine screens to improve screening efficiency, iron concentrate grade, and reduce silica content, thus achieving a new generation of fine screening and grading equipment in iron ore beneficiation plants. Electromagnetic screens are stainless steel wire woven composite meshes, characterized by high open area and easy mesh modification. However, their service life is short, requiring replacement after approximately 20 days of continuous operation, resulting in significant maintenance workload. Polyurethane elastomers are polymer materials with a modulus significantly different from that of metals. Therefore, sieve plates made from polyurethane elastomers suffer from low porosity and poor impact resistance. As is well known, the sieve surface is the working surface of a screening machine and a crucial component affecting screening quality and quantity. Therefore, those skilled in the art urgently need to develop a production method for embedding steel wire into polyurethane sieve mesh to overcome the shortcomings of existing technologies and meet current market demands and performance requirements. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the main objective of the present invention is to provide a production method for embedding steel wire into a polyurethane screen.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A method for producing a steel wire embedded polyurethane screen further includes the following steps: First, mixing materials evenly, extruding, cross-linking, and expanding to produce polyurethane heat shrink tubing; Second, embedding steel wires into the polyurethane heat shrink tubing to obtain steel wire embedded polyurethane heat shrink tubing; Third, producing a screen by weaving or welding the steel wire embedded polyurethane heat shrink tubing; Fourth, heating and shrinking the obtained screen to coat the steel wires with polyurethane, thus obtaining the steel wire embedded polyurethane screen.

[0006] Aragonite

[0007] Polyurethane heat shrink tubing has a "thermal memory effect." When a steel wire sleeve is embedded in the heat shrink sleeve and heated evenly by a heat source, the inner diameter of the polyurethane heat shrink tubing decreases after being heated, and it tightly binds to the steel wire.

[0008] Thermoplastic polyurethane elastomer, also known as TPU, can be melt-extruded.

[0009] Furthermore, the first step of uniformly mixing the materials consists of 100 parts by weight of thermoplastic polyurethane elastomer, 0.5-1 parts by weight of di-tert-butylperoxyisopropylbenzene, 0.1-0.3 parts by weight of triallyl isocyanate, 0.5-1 parts by weight of lubricant, and 1-2 parts by weight of antioxidant. The thermoplastic polyurethane elastomer is dried at 80-90°C for 4-6 hours and then extruded through a single-screw extruder. The extruder temperature is 165-175°C in zone 1, 175-185°C in zone 2, 180-190°C in zone 3, and 165-175°C at the die head.

[0010] Furthermore, the first step of expansion is carried out in an expansion machine, the heating medium of which is glycerin, and the expansion temperature is in the range of 180~190℃.

[0011] Furthermore, the inner diameter of the first-step polyurethane heat shrink tubing before shrinkage is 1.6~6.4mm, the inner diameter after shrinkage is 0.8~3.2mm, and the wall thickness is 0.25~0.3mm.

[0012] Furthermore, the diameter of the steel wire in the second step is 0.8~3.2mm.

[0013] Furthermore, the fourth step of heating and shrinking involves heating with an oven or hot air gun at a temperature of 100~125℃.

[0014] The beneficial effects of this invention are:

[0015] This invention discloses a method for producing a steel wire embedded polyurethane screen. The method involves extruding, cross-linking, and expanding polyurethane heat-shrinkable tubing, then embedding steel wires into the tubing, and continuing to weave or weld the screen. Finally, heat shrinkage is used to coat the steel wires with polyurethane, resulting in a steel wire embedded polyurethane (TPU) screen. This screen surface exhibits advantages such as high elongation, good wear resistance, high tensile strength and tear resistance, and high porosity. It also boasts advantages such as long service life, good screening permeability, strong self-cleaning properties, high screening efficiency, light weight, easy installation, convenient maintenance, low noise, and strong adaptability. The aforementioned steel wire embedded polyurethane screen is a flexible screen surface similar to a metal wire woven screen. It consists of steel wire screen bars and a wear-resistant cross-linked TPU heat-shrinkable coating on the steel wire surface. The screen bars are arranged in a cross pattern through weaving or welding, resulting in a high porosity. The method disclosed in this invention does not utilize conventional three-component casting materials or casting machines, resulting in low production costs, high production efficiency, and a simple and easy-to-implement process. Attached Figure Description

[0016] Appendix Figure 1 This is a schematic diagram of the heating and shrinkage process before and after in Embodiment 1 of the present invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto. Example 1

[0018] Raw materials and equipment: 1.2mm diameter steel wire, selected from 1Cr18Ni9Ti and Elastollan1190A steel wires; Keli New Materials KB-S; Kemaowei COLINK BIPB-40Kpd; Woljia heat shrink tubing production line; and Anner GWS drying oven.

[0019] The production method of steel wire embedded in polyurethane screen also includes the following steps: Step 1: Mix materials evenly, extrude, cross-link, and expand to produce polyurethane heat shrink tubing. Expansion is performed in an expander, the heating medium of which is glycerin, and the expansion temperature is 190℃. The evenly mixed materials are, by weight, 100 parts of thermoplastic polyurethane elastomer, 0.75 parts of di-tert-butylperoxyisopropylbenzene, 0.2 parts of triallyl isocyanate, 0.75 parts of lubricant, and 1.5 parts of antioxidant, mixed evenly. The thermoplastic polyurethane elastomer is dried at 85℃ for 5 hours, and then extruded using a single-screw extruder. The extruder temperatures are 170℃ in zone 1, 180℃ in zone 2, 185℃ in zone 3, and 170℃ at the die head. The inner diameter of the polyurethane heat shrink tubing before shrinkage is 2.4mm, the inner diameter after shrinkage is 1.2mm, and the wall thickness is 0.3mm. The second step is to insert steel wire into the polyurethane heat shrink tubing to obtain steel wire embedded polyurethane heat shrink tubing. The third step is to produce a screen by weaving or welding the steel wire embedded polyurethane heat shrink tubing. The fourth step is to heat and shrink the obtained screen to coat the steel wire with polyurethane. The heating and shrinking is done by heating in an oven or hot air gun at a temperature of 100℃, thus obtaining the steel wire embedded polyurethane screen.

[0020] Product performance: Hardness 91.6 Shore A, tensile strength 39.5 MPa, tensile elongation 486.6%, tear strength 98.8 KN / m, resilience 39.5%, relative volumetric abrasion 21.8 mm3. Example 2

[0021] Raw materials: 3.2mm OCr18Ni12Mo2Ti steel wire, Texin990R granules, TAIC from Subei Special Chemical Plant; 2-tert-butylperoxyisopropylbenzene Rheinland VC-40CC, Woljia heat shrink tubing production line, and 8611B heat gun.

[0022] The production method of steel wire embedded in polyurethane screen also includes the following steps: Step 1: Mix materials evenly, extrude, cross-link, and expand to produce polyurethane heat shrink tubing. Expansion is performed in an expander, the heating medium of which is glycerin, and the expansion temperature is 185℃. The evenly mixed materials are, by weight, 100 parts of thermoplastic polyurethane elastomer, 1 part of di-tert-butylperoxyisopropylbenzene, 0.3 parts of triallyl isocyanate, 1 part of lubricant, and 1 part of antioxidant, mixed evenly. The thermoplastic polyurethane elastomer is dried at 90℃ for 6 hours, and then extruded through a single-screw extruder. The machine outlet temperatures are 175℃ in zone 1, 185℃ in zone 2, 190℃ in zone 3, and 175℃ at the machine head. The inner diameter of the polyurethane heat shrink tubing before shrinkage is 6.4mm, the inner diameter after shrinkage is 3.2mm, and the wall thickness is 0.3mm. The second step is to insert steel wire into the polyurethane heat shrink tubing to obtain steel wire embedded in the polyurethane heat shrink tubing. The third step is to produce a screen by weaving or welding the steel wire embedded in the polyurethane heat shrink tubing. The fourth step is to heat and shrink the obtained screen to coat the steel wire with polyurethane. The heating and shrinking is done by heating in an oven or hot air gun at a temperature of 100℃, thus obtaining the steel wire embedded polyurethane screen.

[0023] Product performance: Hardness 91.5 Shore A, tensile strength 38.3 MPa, tensile elongation 486.5%, tear strength 98.8 KN / m, resilience 38.8%, relative volumetric abrasion 21.9 mm3. Example 3

[0024] Raw materials: 0.8mm steel wire selected from OCr18Ni12Mo2Ti, 6185A granules, TAIC from Subei Special Chemical Plant; Fangruida BIPB-96 tert-butylperoxyisopropylbenzene, Woljia heat shrink tubing production line, and HL1820S hot air gun.

[0025] The production method of steel wire embedded in polyurethane screen also includes the following steps: Step 1: Mix materials evenly, extrude, cross-link, and expand to produce polyurethane heat shrink tubing. Expansion is performed in an expander, the heating medium of which is glycerin, and the expansion temperature is within the range of 180℃. The evenly mixed materials are, by weight, 100 parts of thermoplastic polyurethane elastomer, 0.5 parts of di-tert-butylperoxyisopropylbenzene, 0.1 parts of triallyl isocyanate, 0.5 parts of lubricant, and 1 part of antioxidant, mixed evenly. The thermoplastic polyurethane elastomer is dried at 80℃ for 4 hours, and then extruded using a single-screw extruder. The extruder temperatures are 165℃ in zone 1, 175℃ in zone 2, 180℃ in zone 3, and 165℃ at the die head. The inner diameter of the polyurethane heat shrink tubing is 1.6mm before shrinkage, 0.8mm after shrinkage, and 0.25mm in wall thickness. The second step is to insert steel wire into the polyurethane heat shrink tubing to obtain steel wire embedded polyurethane heat shrink tubing. The third step is to produce a screen by weaving or welding the steel wire embedded polyurethane heat shrink tubing. The fourth step is to heat and shrink the obtained screen to coat the steel wire with polyurethane. The heating and shrinkage is carried out by heating in an oven or hot air gun at a temperature of 100℃, thus obtaining the steel wire embedded polyurethane screen.

[0026] Product performance: Hardness 91.9 Shore A, tensile strength 39.7 MPa, tensile elongation 479.3%, tear strength 99.8 KN / m, resilience 38.9%, relative volumetric abrasion 22.6 mm3.

[0027] Note: Refer to GB / T33091-2016 Polyurethane Screen Plate.

Claims

1. A method for producing a steel wire embedded polyurethane screen, characterized by, Further comprising the following steps: The first step, mixing the materials uniformly, extruding, cross-linking, expanding to produce the polyurethane heat-shrinkable tube; the first step of mixing the materials uniformly is to mix the thermoplastic polyurethane elastomer 100 parts, di-tert-butyl peroxide isopropyl benzene 0.5-1 part, triallyl isocyanurate 0.1-0.3 part, lubricant 0.5-1 part, antioxidant 1-2 part uniformly according to the weight fraction, drying the thermoplastic polyurethane elastomer at 80-90 DEG C for 4-6 h, and then extruding into shape through a single screw extruder, wherein the extruder temperature is 165-175 DEG C in zone 1, 175-185 DEG C in zone 2, 180-190 DEG C in zone 3, and 165-175 DEG C in the head; the first step of the polyurethane heat-shrinkable tube has an inner diameter of 1.6-6.4 mm before shrinking, an inner diameter of 0.8-3.2 mm after shrinking, and a wall thickness of 0.25-0.3 mm; the second step is to embed the steel wire into the polyurethane heat-shrinkable tube to obtain the steel wire embedded polyurethane heat-shrinkable tube; the third step is to produce the screen mesh by weaving or welding the steel wire embedded polyurethane heat-shrinkable tube; the fourth step is to heat and shrink the obtained screen mesh to make the polyurethane cover on the steel wire, thereby obtaining the steel wire embedded polyurethane screen mesh.

2. A method of producing a steel wire embedded polyurethane screen according to claim 1, characterized in that, The first step of expansion is to expand in the expansion machine, and the heating medium of the expansion machine is glycerol, and the expansion temperature is in the range of 180-190 DEG C.

3. A method of producing a steel wire embedded polyurethane screen according to claim 1, characterized in that, The second step of the steel wire has a diameter of 0.8-3.2 mm.

4. A method of producing a steel wire embedded polyurethane screen according to claim 1, characterized in that, The fourth step of heating and shrinking is to heat with an oven or a hot air gun, and the heating temperature is 100-125 DEG C.

Images