Agricultural machinery rubber belt and preparation method thereof

Abstract

The invention relates to the field of agricultural machinery belt production, in particular to an agricultural machinery rubber belt and a preparation method thereof. The rubber and plastic alloy (nitrile rubber-polyvinyl chloride blending system), the natural rubber and the chloroprene rubber have a synergistic effect, so that the agricultural machine belt has excellent ozone resistance, weather aging resistance, oil resistance, flame retardance and medium resistance, the wear resistance and tear strength are remarkably improved, and the service life is prolonged by 30% or above compared with that of a traditional product.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery belt production, specifically to an agricultural machinery rubber belt and its preparation method. Background Technology

[0002] Currently, in the field of agricultural machinery belt production, the mainstream material systems are divided into two categories. One category is natural rubber series formulations, which use natural rubber as the base material and are made by combining conventional reinforcing agents, softeners, and vulcanization systems; the other category is chloroprene rubber series formulations, which use chloroprene rubber as the core base material and are supplemented with corresponding compounding agents to achieve performance regulation.

[0003] Although natural rubber series formulations have low raw material costs and good processing fluidity, their aging resistance is significantly lacking. When exposed to sunlight, rain, and alternating high and low temperatures in the field for a long time, they are prone to cracking, hardening, and loss of elasticity, which leads to a shortened service life of agricultural machinery belts and increases replacement costs for users.

[0004] Chloroprene rubber series formulations have better aging resistance, weather resistance and mechanical properties, but chloroprene rubber raw materials are expensive, which directly increases the production cost of products; at the same time, chloroprene rubber has strict storage requirements, and must be stored in a dark and sealed place, otherwise it is prone to self-crosslinking reaction, which affects the processing performance; and during the processing, it is easy to encounter process problems such as large die expansion and low extrusion efficiency, resulting in high surface roughness of semi-finished products and unstable subsequent molding and bonding quality. Summary of the Invention

[0005] This invention aims to provide an agricultural machinery rubber belt and its preparation method, the specific solution of which is as follows: An agricultural machinery rubber belt comprises the following components by mass: 10-30 parts of chloroprene rubber 40-60 parts of rubber-plastic alloy 20-40 parts of natural rubber 20-40 parts carbon black 20-40 parts of silica 5-25 parts of nylon staple fiber 5-25 parts of cotton powder short fiber.

[0006] The rubber-plastic alloy is a blended modified alloy of nitrile rubber and polyvinyl chloride, wherein the amount of acrylonitrile added to the nitrile rubber is 20%-30%.

[0007] The carbon black is N330 or N660 type carbon black.

[0008] The silica is precipitated silica, and the addition ratio of silica to carbon black is 1:1.

[0009] An agricultural machinery rubber belt further includes the following components: 5-10 parts of softener 3-6 parts zinc oxide 1-2 parts stearic acid 5-15 parts of tackifying resin Anti-aging agent 2-4 parts 1-3 parts sulfur Accelerator 1.5-2.5 parts 2-5 parts adhesive.

[0010] A method for preparing agricultural machinery rubber belts includes the following steps in sequence: mixing, extrusion, calendering, molding, cutting, wrapping, and vulcanization; the calendering process uses a three-roll calender with an upper roll temperature of 40±5℃, a middle roll temperature of 40±5℃, and the rear roll is not used; the roll speed is 15-20m / min; and the wrapping tension is controlled at 80-100N / m.

[0011] The mixing process is as follows: a two-stage mixing method is adopted. The first stage mixing temperature is 85-95℃ and the time is 3.5-4.0min, in which the base material, reinforcing agent, softener and antioxidant are mixed evenly. The second stage mixing temperature is 80-90℃ and the time is 2.5-3min, in which vulcanizing agent and accelerator are added.

[0012] The extrusion process is as follows: the extrusion temperature is controlled at 85-95℃, and the screw speed is 30-50 r / min.

[0013] The cloth wrapping process is as follows: the cloth material is a self-made wiping canvas; the cloth tension is 60-80 N / m; the wrapping overlap is 15-20 mm; and the wrapping speed is synchronized with the fabric conveying speed at 3-5 m / min.

[0014] The vulcanization process is as follows: vulcanization temperature 160℃, vulcanization pressure 4.0-9.0MPa, vulcanization time calculated based on V-belt thickness 1.5-2.0min / mm.

[0015] This invention has the following advantages: 1. The synergistic effect of rubber-plastic alloy (nitrile rubber-polyvinyl chloride blend system) with natural rubber and chloroprene rubber gives agricultural machinery belts excellent ozone resistance, weather aging resistance, oil resistance, flame retardancy, and media resistance. In addition, the wear resistance and tear strength are significantly improved, and the service life is extended by more than 30% compared with traditional products.

[0016] 2. By partially replacing neoprene rubber with rubber-plastic alloys, raw material costs can be reduced by 20%-30% without compromising performance, significantly enhancing the product's market competitiveness.

[0017] 3. The optimized formula reduces the dependence on chloroprene rubber, reduces the risk of self-crosslinking during storage, widens the processing window, and makes operation more convenient.

[0018] 4. Carbon black and silica are blended in a 1:1 ratio, and combined with nylon short fibers and cotton powder short fibers to form a composite system of "inorganic reinforcement + organic fiber reinforcement", which improves rigidity and wear resistance while ensuring flexibility.

[0019] 5. The extrusion speed of semi-finished products is increased by 20%-25%, the expansion rate of the extrusion die is controlled within 5%, the surface finish reaches Ra≤0.8μm, the molding adhesion strength is increased by more than 10%, and the defect rate of subsequent processes is reduced to less than 1%. Detailed Implementation

[0020] 1) Formula composition (by weight)

[0021] 2) Core Logic of Formula Optimization Synergistic formulation of base materials: A ternary base material system is used, with rubber-plastic alloy (40-60 parts) as the main component and chloroprene rubber (10-30 parts) and natural rubber (20-40 parts) as auxiliary components, to balance cost and performance. The high aging resistance of rubber-plastic alloy compensates for the shortcomings of natural rubber, while the low cost and processability of natural rubber reduce the overall cost of the formulation, and a small amount of chloroprene rubber further enhances key performance characteristics.

[0022] Optimized reinforcement system: Carbon black and silica are blended in a 1:1 ratio, combined with nylon short fibers and cotton powder short fibers to form a composite system of "inorganic reinforcement + organic fiber reinforcement", which improves rigidity and wear resistance while ensuring flexibility.

[0023] Compounding agent system control: Select compound antioxidants and accelerators to ensure vulcanization efficiency and aging protection effect; tackifying resin and special adhesive work together to solve the fiber-rubber bonding problem and ensure molding quality.

[0024] 3) Adaptability to processing technology This formula can be directly applied to traditional agricultural machinery belt mixing-extrusion-calendering-forming-cutting-coating-vulcanization combined production lines without the need for equipment modification.

[0025] Mixing process: A two-stage mixing method is adopted. The first stage mixing temperature is 85-95℃ and the time is 3.5-4.0min, in which the base material, reinforcing agent, softener, antioxidant and other ingredients are mixed evenly. The second stage mixing temperature is 80-90℃ and the time is 2.5-3min, in which vulcanizing agent, accelerator and other ingredients are added to ensure uniform dispersion and prevent premature vulcanization.

[0026] Extrusion process: The extrusion temperature is controlled at 85-95℃ and the screw speed is 30-50r / min. Due to the optimization of the formulation processing fluidity, the extrusion speed is increased by more than 20% compared with the traditional chloroprene rubber formulation. The die expansion rate is significantly reduced and the surface of the semi-finished product is smooth and without defects.

[0027] Calendering process Equipment: Three-roll calender (roll diameter φ610mm, roll width 1800mm) Process parameters: upper roller temperature 40±5℃, middle roller temperature 40±5℃, rear roller not used; roller speed 15-20m / min; fabric tension controlled at 80-100N / m, using an active unwinding + tension feedback adjustment system.

[0028] Key operating points: After the rubber compound is mixed in two stages, it is evenly fed into the calender through a feeding device. The fabric is synchronously bonded to the rubber sheet by the guide roller. During the calendering process, the roller gap is adjusted in real time by an online thickness detection device to ensure uniform thickness of the rubber sheet.

[0029] Vertical splicing process Equipment: CNC film splicing machine (including heating and pressurizing device, alignment and positioning system, and thickness detection module) Process parameters: splicing width 1020-1040mm; splicing temperature 40-50℃ (matching the hot tack flow temperature of the adhesive); splicing pressure 2.0-2.5Mpa.

[0030] Key points of operation: Film conveying and positioning: The film is cut according to its width and conveyed laterally. After the previous film is conveyed to the docking station by the conveyor belt, its position is fixed by infrared positioning sensors and mechanical limit devices. The next film is conveyed to the docking station by the conveyor belt and guided by the vision alignment system to accurately overlap with the previous film (alignment deviation ≤ 0.5mm) to form an overlap area of ​​5-8mm.

[0031] Pressing and bonding with pressure rollers: The adjustable pressure roller assembly descends to apply uniform pressure (2.0-2.5MPa) to the overlap area. At the same time, the pressure rollers are preheated to 40-50℃ to promote the softening and fusion of the adhesive on the overlap surface, expel air, and ensure tight bonding.

[0032] Synchronous vertical cutting: The pressure roller remains in a pressing state, the vertical cutting module starts, and cuts parallel along the center line of the overlap area (or the preset cutting line) to cut off the 5-8mm wide overlap in one go, so that the front and rear films form a fresh and flat vertical cut.

[0033] Instant adhesion at the cut: After cutting, the pressure roller continues to press for 2-3 seconds. Utilizing the adhesive's own viscosity and the action of the tackifying system, the cut edges of the two sheets quickly adhere, forming a complete and continuous sheet. Ultimately, the fiber-oriented sheet becomes a continuous sheet perpendicular to the fiber direction.

[0034] Molding process (top adhesive - cord - bottom adhesive composite) Equipment: CNC V-belt forming machine (including cord laying device and interlayer bonding device) Process parameters: molding temperature is room temperature; cord tension is 8-12N / cord; cord density is set according to V-belt type (e.g., 6-8 cords / mm for type A, 8-10 cords / mm for type B); interlayer pressing pressure is 1.5-2.0MPa.

[0035] Key points of operation: First, the top adhesive film is laid on the surface of the molding drum. Then, the polyester cords are evenly arranged on the top adhesive surface through the cord laying device. Next, the bottom adhesive film is covered and then pressed and bonded by the interlayer bonding device to form a three-layer composite structure of "top adhesive-cords-bottom adhesive". The composite structure is dense and free of bubbles.

[0036] Cutting process (precise beveling of composite structures) Equipment: CNC beveling machine (dedicated to composite structures) Process parameters: Cutting speed 5-8m / min, blade speed 3000-4000r / min; cutting angle set according to model (Type A 34°, Type B 38°), angle tolerance ±0.1°; cutting width set according to finished product specifications, tolerance ±0.2mm.

[0037] Key points of operation: After the composite molding of the roll material is positioned and fixed, the servo motor drives the roll material to rotate synchronously with the blade feed. During the cutting process, the cooling air cools the blade to prevent the adhesive from sticking together. After cutting, a single V-belt blank is formed, and the two sides of the blank are flat and without flash.

[0038] Fabric wrapping process (tight wrapping of the preform) Equipment: CNC fabric wrapping machine (including fabric tension control system and guiding device) Process parameters: The covering material is a self-made wiping cloth canvas; the covering tension is 60-80 N / m; the covering overlap is 15-20 mm; the wrapping speed is synchronized with the fabric conveying speed (3-5 m / min).

[0039] Key operating points: The V-belt preform is precisely fed into the wrapping machine via a guiding device. After preheating (20-30℃), the wrapping fabric is tightly wrapped around the surface of the preform. The tension feedback adjustment system prevents the wrapping fabric from wrinkling or loosening, ensuring that the wrapping fabric and the preform adhere tightly.

[0040] Equipment: Flat vulcanizing machine Process parameters: vulcanization temperature 160±3℃, vulcanization pressure 4.0-9.0MPa, vulcanization time calculated according to V-belt thickness (1.5-2.0min / mm).

[0041] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A rubber belt for agricultural machinery, characterized in that, Includes the following mass components: 10-30 parts of chloroprene rubber 40-60 parts of rubber-plastic alloy 20-40 parts of natural rubber 20-40 parts carbon black 20-40 parts of silica 5-25 parts of nylon staple fiber 5-25 parts of cotton powder short fiber.

2. The agricultural machinery rubber belt as described in claim 1, characterized in that: The rubber-plastic alloy is a blended modified alloy of nitrile rubber and polyvinyl chloride, wherein the amount of acrylonitrile added to the nitrile rubber is 20%-30%.

3. The agricultural machinery rubber belt as described in claim 1, characterized in that: The carbon black is N330 or N660 type carbon black.

4. An agricultural machinery rubber belt as described in any one of claims 1 or 3, characterized in that: The silica is precipitated silica, and the addition ratio of silica to carbon black is 1:

1.

5. The agricultural machinery rubber belt as described in claim 1, characterized in that, It also includes the following components: 5-10 parts of softener 3-6 parts zinc oxide 1-2 parts stearic acid 5-15 parts of tackifying resin Anti-aging agent 2-4 parts 1-3 parts sulfur Accelerator 1.5-2.5 parts 2-5 parts adhesive.

6. A method for preparing the agricultural machinery rubber belt as described in claim 1, characterized in that, The process includes the following steps in sequence: mixing, extrusion, calendering, forming, cutting, wrapping, and vulcanization; the calendering process uses a three-roll calender with the upper roll temperature at 40±5℃, the middle roll temperature at 40±5℃, and the rear roll not used; the roll speed is 15-20m / min; and the wrapping tension is controlled at 80-100N / m.

7. The method for preparing an agricultural machinery rubber belt as described in claim 6, characterized in that, The mixing process is as follows: a two-stage mixing method is adopted. The first stage mixing temperature is 85-95℃ and the time is 3.5-4.0min, in which the base material, reinforcing agent, softener and antioxidant are mixed evenly. The second stage mixing temperature is 80-90℃ and the time is 2.5-3min, in which vulcanizing agent and accelerator are added.

8. The method for preparing an agricultural machinery rubber belt as described in claim 6, characterized in that, The extrusion process is as follows: the extrusion temperature is controlled at 85-95℃, and the screw speed is 30-50 r / min.

9. The method for preparing an agricultural machinery rubber belt as described in claim 6, characterized in that, The cloth wrapping process is as follows: the cloth material is a self-made wiping canvas; the cloth tension is 60-80 N / m; the wrapping overlap is 15-20 mm; and the wrapping speed is synchronized with the fabric conveying speed at 3-5 m / min.

10. The method for preparing an agricultural machinery rubber belt as described in claim 6, characterized in that, The vulcanization process is as follows: vulcanization temperature 160℃, vulcanization pressure 4.0-9.0MPa, vulcanization time calculated based on V-belt thickness 1.5-2.0min / mm.

Images