PVC conveyor belt cover material with high wear resistance and preparation method thereof

Abstract

The present application relates to a kind of PVC conveying belt surface layer material with high wear resistance and its preparation method, the component of the surface layer material includes by weight parts: PVC paste resin: 100 parts;SBR emulsion (by solid content): 5-15 parts;BR emulsion (by solid content): 3-10 parts;Maleic anhydride grafting polyethylene: 0.3-1 part.The present application improves the wear resistance and dynamic friction coefficient of surface layer material by the synergistic effect of SBR emulsion and BR emulsion, gives material good elasticity and buffering capacity, and possibly improves the running stability of conveying belt and the flexibility at low temperature, reduces the risk of low temperature brittle fracture.And by means of maleic anhydride grafting polyethylene compatibilizer improves interface bonding, enhances the interface bonding force between PVC matrix and rubber dispersed phase, makes the blending system more stable, not easy to phase separation and interface peeling, so that surface layer material can more effectively resist the friction and wear of material, thereby significantly prolong the service life of conveying belt.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high polymer composite materials, and relates to a PVC conveying belt surface layer material with high wear resistance and a preparation method thereof. BACKGROUND

[0002] Polyvinyl chloride (PVC) conveying belts have been widely used in many industrial fields such as mining, coal, port, building materials, chemical industry and grain transportation due to their relatively low cost, good chemical resistance, flame resistance and certain weather resistance. Among them, the surface layer material (cover rubber) of the conveying belt directly contacts with the conveyed materials and bears various friction, wear, impact and environmental factors during operation, and its performance directly determines the overall service life and operation reliability of the conveying belt.

[0003] However, the traditional PVC surface layer material has high hardness but relatively poor toughness, and is prone to brittle fracture in low temperature environment. More importantly, its wear resistance often cannot meet the material conveying requirements in high strength, long distance and harsh working conditions, resulting in premature wear and failure of the conveying belt surface layer, which increases the production cost and downtime maintenance time.

[0004] In order to improve the performance of PVC, plasticizers are usually used to improve its flexibility, or it is blended with other polymers for modification. In terms of blending modification, introducing rubber-like elastomers into PVC is a common method to improve its toughness and wear resistance. For example, styrene-butadiene rubber (SBR) has good wear resistance and physical and mechanical properties, and butadiene rubber (BR) is known for its excellent elasticity and low temperature resistance.

[0005] However, PVC is a polymer with strong polarity, while the polarity of general rubbers such as SBR and BR is relatively weak, and the thermodynamic compatibility between them is poor. Direct blending often leads to serious phase separation, weak interfacial bonding, and the rubber phase cannot be uniformly dispersed in the PVC matrix in ideal size and morphology, resulting in poor modification effect and even possible decrease in mechanical properties of the material.

[0006] In addition, therefore, it is of important practical significance and economic value to develop a PVC conveying belt surface layer material that can significantly improve wear resistance while considering good elasticity and interfacial bonding strength, and has a reasonable preparation process, so as to prolong the service life of the conveying belt and reduce operating costs. SUMMARY

[0007] In view of at least one of the deficiencies mentioned in the background art, the present application aims to provide a PVC conveying belt surface layer material with high wear resistance and a preparation method thereof, which has high wear resistance, can effectively prolong the service life of the conveying belt and improve its comprehensive use performance.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A PVC conveyor belt surface material with high abrasion resistance, comprising, by weight, the following components:

[0010] PVC paste resin: 100 parts;

[0011] SBR emulsion (based on solid content): 5-15 parts;

[0012] BR emulsion (based on solids content): 3-10 parts;

[0013] Maleic anhydride-grafted polyethylene: 0.3-1 part.

[0014] In this scheme, PVC paste resin serves as the main matrix material, providing basic molding and processing properties, physical strength, and chemical stability, as well as a certain degree of wear resistance. SBR emulsion primarily contributes to wear resistance and dynamic friction performance, while BR emulsion aims to provide elastic cushioning, helping to absorb impact energy and reduce the cutting and ploughing effects of abrasives on the material surface. The two work synergistically to form a complementary micro-textured structure, increasing the coefficient of friction and indirectly improving the material's wear resistance. This, in turn, enhances the grip of the PVC conveyor belt surface material and improves its performance under dynamic conditions. Maleic anhydride-grafted polyethylene (MAH-g-PE) acts as a compatibilizer, improving the interfacial bonding between the thermodynamically incompatible PVC and SBR / BR emulsions. This allows the rubber phase to be more finely and uniformly dispersed in the PVC matrix, forming a more stable blend system with fewer defects. This enables the SBR and BR emulsions to fulfill their technical functions and may result in superior overall performance compared to simple physical mixing of components or the absence of a compatibilizer, particularly a significant improvement in wear resistance.

[0015] Preferably, the amount of SBR emulsion used is 8-12 parts based on solid content; the amount of BR emulsion used is 4-8 parts based on solid content.

[0016] Preferably, the styrene content in the SBR emulsion is 20-30%.

[0017] Preferably, the solid content of the SBR emulsion is ≥55%, and the solid content of the BR emulsion is ≥50%.

[0018] Therefore, emulsions with high solids content have less residual moisture during curing, making it easier to form a phase separation structure.

[0019] Preferably, the particle size of the SBR emulsion is 0.1-0.3 micrometers, and the particle size of the BR emulsion is 0.2-0.5 micrometers.

[0020] Therefore, the smaller particle size of SBR and BR emulsions can enhance the packing density of emulsion particles and promote the formation of microstructure.

[0021] Preferably, the surface layer material further comprises at least one of fillers, solvent regulators, plasticizers, surfactants, nucleating agents, and stabilizers.

[0022] Preferably, the surface layer material further comprises 5-10 parts of filler.

[0023] The filler is at least one of calcium carbonate, silicon dioxide, carbon black, kaolin, and talc.

[0024] Preferably, the filler is silica sand or calcium carbonate, and the particle size of the silica sand and calcium carbonate is 5-20 micrometers.

[0025] Therefore, the addition of fillers helps to enhance the stability of the uneven structure through mechanical embedding effect.

[0026] Preferably, the surface layer material further comprises 0.5-2 parts of solvent modifier.

[0027] Preferably, the solvent regulator is a volatile hydrophilic solvent, preferably ethanol or acetone.

[0028] Therefore, adding a solvent regulator is beneficial for promoting phase separation of emulsion particles during solvent evaporation.

[0029] Preferably, the surface material further comprises 1-6 parts of plasticizer, preferably at least one of dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl terephthalate (DOTP), and epoxidized soybean oil.

[0030] Preferably, the surface layer material further comprises 0.3-1.4 parts of a nucleating agent.

[0031] Preferably, the nucleating agent is at least one of diatomaceous earth or nano-silica. The particle size of the diatomaceous earth or nano-silica is 20-50 nm.

[0032] Thus, the nucleating agent acts as a nucleation point to induce emulsion particles to preferentially aggregate in specific areas during the curing process, forming a controllable uneven structure.

[0033] Preferably, the surface layer material further comprises 0.2-2 parts of stabilizer.

[0034] Preferably, the stabilizer is a calcium-zinc composite stabilizer.

[0035] The preparation method of the PVC conveyor belt surface material described above includes the following steps:

[0036] Add PVC paste resin, SBR emulsion, BR emulsion, and maleic anhydride-grafted polyethylene into a mixer and stir for 30-60 minutes at a temperature of 35-45℃ and a speed of 500-1500 rpm to form a PVC surface paste.

[0037] A lightweight conveyor belt has a fabric skeleton and a surface layer coated on the fabric skeleton, the surface layer being formed by curing the aforementioned PVC conveyor belt surface layer material.

[0038] Furthermore, the curing conditions are as follows: first, dry at 40-60℃ for 30-60 minutes, then heat to 100-120℃ and dry for 10-30 minutes.

[0039] The 40-60℃ temperature range is the low-temperature, slow-drying stage. This stage facilitates the gentle and complete evaporation of moisture, preventing premature surface sealing and internal solvent residue caused by rapid heating. This reduces the risk of defects such as bubbles and pinholes in the final product. Simultaneously, the lower temperature and slower drying rate promote the orderly accumulation and initial fusion of emulsion particles, as well as sufficient migration, orientation, and potential physical / chemical interactions of maleic anhydride-grafted polyethylene at the interface, laying the foundation for a good interfacial layer. This stage also effectively reduces the accumulation of internal stress during the curing process.

[0040] The 100-120℃ high-temperature rapid drying stage aims to promote the complete plasticization of PVC paste resin and form a continuous matrix phase. For the rubber component, high temperature helps to perfect its physical network; if the formulation contains a small amount of reactive groups or a trace amount of crosslinking aids are added subsequently, high temperature may also promote a slight crosslinking reaction, further stabilizing the morphology and properties of the rubber phase. At the same time, high temperature also ensures the final stability of the compatibilizer and maximizes the interfacial bonding strength.

[0041] This phased curing strategy with different temperature zones differs from the traditional single-stage high-temperature rapid curing. It may have a positive but not obvious impact on the microstructure of the material (such as phase domain size, interface layer thickness and strength, crystallinity, etc.), which may help to form a more layered micro-concave-convex structure, thereby significantly improving its macroscopic properties, increasing grip, and improving wear resistance.

[0042] Traditional PVC paste resin curing processes often employ one-step high-temperature plasticizing molding. Although the process is simple, factors such as excessively rapid heating, insufficient evaporation of solvents inside the paste, and high internal stress can affect the microstructure and macroscopic properties of the final product, making it difficult to fully realize the potential of each component. This limitation is particularly pronounced when pursuing specific properties such as high wear resistance.

[0043] Furthermore, the surface material is coated onto the surface of the fabric skeleton by scraping or rolling, with a coating thickness of 1-5 mm.

[0044] The beneficial effects of this invention are:

[0045] This invention utilizes the synergistic effect of SBR and BR emulsions. The SBR emulsion primarily improves the wear resistance and dynamic friction coefficient of the surface layer material to cope with wear during material transport. The introduction of the BR emulsion imparts good elasticity and cushioning capacity to the material, helping to absorb impacts, reduce damage to the belt surface from hard materials, and potentially improve the smoothness of the conveyor belt's operation and its flexibility at low temperatures, reducing the risk of low-temperature brittleness. Furthermore, the use of maleic anhydride-grafted polyethylene compatibilizer improves interfacial bonding, enhancing the interfacial adhesion between the PVC matrix and the rubber dispersed phase, making the blend system more stable and less prone to phase separation and interfacial delamination. This allows the surface layer material to more effectively resist friction and wear from materials, thereby significantly extending the service life of the conveyor belt. Detailed Implementation

[0046] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0047] Raw material description

[0048] PVC paste resin: grade PSH-30, K value approximately 70-72, Shenyang Chemical Co., Ltd.

[0049] SBR Emulsion: SBR-1502 type emulsion, white homogeneous emulsion, solid content 45±1%, Shandong Xianyuan Chemical Technology Co., Ltd.

[0050] BR emulsion: BR-9000 type emulsion, solid content 42±1%, Yanshan Petrochemical.

[0051] Maleic anhydride-grafted polyethylene (MAH-g-PE): Grade CMG9801, grafting rate 0.8-1.2%, Shanghai Dingfen Chemical Technology Co., Ltd.

[0052] Dioctyl phthalate (DOP): Industrial grade, Chuangyi Chemical Co., Ltd.

[0053] Light calcium carbonate: average particle size 15 micrometers, Hebei Hezhen Industrial Co., Ltd.

[0054] Silica sand, average particle size 15 micrometers, Henan Zhuli New Materials Co., Ltd.

[0055] Calcium-zinc composite stabilizer, brand name CZ-208, Shandong Xieheng New Material Technology Co., Ltd.

[0056] Conveyor belt base material: EP200 type polyester canvas, 500mm wide, Zhejiang Hongbang Textile Co., Ltd.

[0057] Example 1

[0058] A PVC conveyor belt surface material with high abrasion resistance, comprising, by weight, the following components:

[0059] PVC paste resin: 100 parts;

[0060] SBR emulsion (by solids content): 10 parts, or approximately 22.2 parts emulsion;

[0061] BR emulsion (by solids content): 6 parts, or approximately 14.3 parts emulsion;

[0062] Maleic anhydride-grafted polyethylene: 0.6 parts.

[0063] A lightweight conveyor belt has a fabric skeleton and a surface layer coated on the fabric skeleton. The surface layer is formed by curing the aforementioned PVC conveyor belt surface layer material, and the fabric skeleton is EP200 type polyester canvas. Its preparation method includes the following steps:

[0064] S1. Add PVC paste resin to a high-speed mixer, then increase the speed to 1000 rpm, and then slowly add SBR emulsion, BR emulsion, and maleic anhydride grafted polyethylene in sequence. Stir for 45 minutes to obtain a uniform and stable surface paste.

[0065] S2. Using a scraper coating method, the prepared surface paste is evenly coated onto the surface of the EP200 polyester canvas substrate, and the dry film thickness of the coating is controlled to be approximately 2.0 mm.

[0066] S3. Place the coated conveyor belt in a forced-air drying oven and first dry it slowly at 50°C for 45 minutes; then raise the oven temperature to 110°C and continue to dry and plasticize it rapidly for 25 minutes.

[0067] S4. Remove and allow to cool naturally to room temperature to obtain the PVC conveyor belt surface sample.

[0068] Example 2

[0069] A PVC conveyor belt surface material with high abrasion resistance, comprising, by weight, the following components:

[0070] PVC paste resin: 100 parts;

[0071] SBR emulsion (by solids content): 15 parts, or approximately 33.3 parts emulsion;

[0072] BR emulsion (by solids content): 3 parts, or approximately 7.1 parts emulsion;

[0073] Maleic anhydride-grafted polyethylene: 0.8 parts;

[0074] Solvent conditioner: ethanol, 1.5 parts;

[0075] Filler: 8 parts silica sand;

[0076] Nucleating agent: Nano-silica, average particle size 30nm, 1 part.

[0077] A lightweight conveyor belt has a fabric skeleton and a surface layer coated on the fabric skeleton. The surface layer is formed by curing the aforementioned PVC conveyor belt surface layer material, and the fabric skeleton is EP200 type polyester canvas. Its preparation method includes the following steps:

[0078] S1. Add PVC paste resin, solvent regulator and nucleating agent to a high-speed mixer and stir at 300 rpm for 10 minutes. Then increase the speed to 1000 rpm and slowly add SBR emulsion, BR emulsion, maleic anhydride grafted polyethylene and light calcium carbonate in sequence. Continue stirring for 45 minutes to obtain a uniform and stable surface paste.

[0079] S2. Using a scraper coating method, the prepared surface paste is evenly coated onto the surface of the EP200 polyester canvas substrate, and the dry film thickness of the coating is controlled to be approximately 2.0 mm.

[0080] S3. Place the coated conveyor belt in a forced-air drying oven and first dry it slowly at 40°C for 60 minutes; then raise the oven temperature to 100°C and continue to dry and plasticize it rapidly for 30 minutes.

[0081] S4. Remove and allow to cool naturally to room temperature to obtain the PVC conveyor belt surface sample.

[0082] Example 3

[0083] A PVC conveyor belt surface material with high abrasion resistance, comprising, by weight, the following components:

[0084] PVC paste resin: 100 parts;

[0085] SBR emulsion (by solids content): 5 parts, or approximately 11.1 parts emulsion;

[0086] BR emulsion (by solids content): 10 parts, or approximately 23.8 parts emulsion;

[0087] Maleic anhydride-grafted polyethylene: 0.4 parts;

[0088] Plasticizer: DOP, 5 parts;

[0089] Filler: Light calcium carbonate, average particle size 1.5 micrometers, 8 parts;

[0090] Heat stabilizer: CZ-208, 0.3 parts.

[0091] A lightweight conveyor belt has a fabric skeleton and a surface layer coated on the fabric skeleton. The surface layer is formed by curing the aforementioned PVC conveyor belt surface layer material, and the fabric skeleton is EP200 type polyester canvas. Its preparation method includes the following steps:

[0092] S1. Add PVC paste resin, DOP plasticizer and heat stabilizer to a high-speed mixer and stir at 300 rpm for 10 minutes. Then increase the speed to 1000 rpm and slowly add SBR emulsion, BR emulsion, maleic anhydride grafted polyethylene and light calcium carbonate in sequence. Continue stirring for 45 minutes to obtain a uniform and stable surface paste.

[0093] S2. Using a scraper coating method, the prepared surface paste is evenly coated onto the surface of the EP200 polyester canvas substrate, and the dry film thickness of the coating is controlled to be approximately 2.0 mm.

[0094] S3. Place the coated conveyor belt in a forced-air drying oven and first dry it slowly at 60°C for 30 minutes; then raise the oven temperature to 120°C and continue to dry and plasticize it rapidly for 20 minutes.

[0095] S4. Remove and allow to cool naturally to room temperature to obtain the PVC conveyor belt surface sample.

[0096] Comparative Example 1

[0097] The difference from Example 3 is that the surface material formulation of Comparative Example 1 did not contain SBR emulsion, BR emulsion, or maleic anhydride-grafted polyethylene. All other components, preparation steps, and parameters remained the same.

[0098] Comparative Example 2

[0099] The difference between Comparative Example 2 and Example 3 is that no BR emulsion was added to the surface material formulation. All other components, preparation steps, and parameters remained the same.

[0100] Comparative Example 3

[0101] The difference between Comparative Example 3 and Example 3 is that the surface material formulation of Comparative Example 3 does not contain maleic anhydride-grafted polyethylene. All other components, preparation steps, and parameters are the same.

[0102] Comparative Example 4

[0103] The difference from Example 3 is that in step S3 of Comparative Example 4, the curing process is as follows: the coated conveyor belt is directly placed in an oven at 110°C for 30 minutes to dry and plasticize, without the low-temperature slow drying step.

[0104] The following performance tests were performed on Examples 1-3 and Comparative Examples 1-4 respectively:

[0105] (1) Akron abrasion test: The test was conducted according to GB / T1689-2014 "Determination of abrasion resistance of vulcanized rubber or thermoplastic rubber (rotary roller abrasion test method)". The sample size was a disc with a thickness of 12.5 mm and a diameter of 63.5 mm. The abrasion wheel speed was 76 r / min, the load was 26.7 N, the deflection angle was 15°, and the abrasion distance was 1.61 km (1 mile). The abrasion volume loss (cm³ / 1.61 km) was calculated. The smaller the abrasion volume loss value, the better the abrasion resistance.

[0106] (2) Tensile strength and elongation at break tests: The tests were conducted in accordance with GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". Dumbbell-shaped No. I specimens were used, and the tensile speed was 500 mm / min.

[0107] (3) Hardness test: The test shall be conducted in accordance with GB / T531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness test (Shore hardness)".

[0108] The test results are shown in Table 1.

[0109] Table 1

[0110]

[0111] Abrasion Resistance Comparison: The abrasion data from Akron show that the abrasion amounts of Examples 1, 2, and 3 are significantly lower than all comparative examples. Specifically, the abrasion data from Comparative Example 1 and Example 3 demonstrate that the introduction of SBR emulsion, BR emulsion, and MAH-g-PE has a significant effect on improving the abrasion resistance of the PVC surface layer. The abrasion data from Comparative Example 4 and Example 3 show the superiority of the two-step curing process—low-temperature slow drying and high-temperature fast drying—over the traditional single-stage high-temperature curing process in preparing high-performance abrasion-resistant surface layers. The two-step curing process may have resulted in a more optimized material microstructure, which is beneficial for enhancing abrasion resistance.

[0112] Mechanical property comparison: The tensile strength and elongation at break of Examples 1, 2, and 3 are all better than those of Comparative Examples 1, 2, 3, and 4, indicating that the formulation and process of the present invention not only improve wear resistance but also improve the overall mechanical properties of the material.

[0113] In summary, the PVC conveyor belt surface material formulation and two-step curing preparation method proposed in this invention can synergistically leverage the advantages of each component, effectively improve the compatibility between PVC and rubber, optimize the microstructure of the material, enhance wear resistance, and simultaneously possess good tensile properties and elongation at break.

[0114] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A PVC conveyor belt surface layer with high wear resistance, characterized in that, The materials constituting the PVC conveyor belt surface layer, by weight, include the following components: PVC paste resin: 100 parts; SBR emulsion, 5-15 parts by solids content; BR emulsion, 3-10 parts by solids content; Maleic anhydride-grafted polyethylene: 0.3-1 part; The material of the PVC conveyor belt surface layer is cured to form the PVC conveyor belt surface layer. The curing conditions are: first, dry at 40-60℃ for 30-60 minutes, and then heat up to 100-120℃ and dry for 10-30 minutes.

2. The PVC conveyor belt surface layer with high wear resistance according to claim 1, characterized in that, The SBR emulsion is used in an amount of 8-12 parts by solids content; the BR emulsion is used in an amount of 4-8 parts by solids content.

3. The PVC conveyor belt surface layer with high wear resistance according to claim 1, characterized in that, The SBR emulsion has a particle size of 0.1-0.3 micrometers, and the BR emulsion has a particle size of 0.2-0.5 micrometers; the SBR emulsion has a solid content of ≥55%, and the BR emulsion has a solid content of ≥50%.

4. The PVC conveyor belt surface layer with high wear resistance according to claim 1, characterized in that, The surface layer material also includes at least one of fillers, solvent regulators, plasticizers, surfactants, nucleating agents, and stabilizers.

5. A PVC conveyor belt surface layer with high wear resistance according to claim 4, characterized in that, The filler comprises 5-10 parts by weight, the solvent modifier comprises 0.5-2 parts by weight, the plasticizer comprises 1-6 parts by weight, the nucleating agent comprises 0.3-1.4 parts by weight, and the stabilizer comprises 0.2-2 parts by weight.

6. A PVC conveyor belt surface layer with high wear resistance according to claim 4, characterized in that, The filler is silica sand or calcium carbonate, and the particle size of the silica sand and calcium carbonate is 5-20 micrometers; the solvent regulator is a volatile hydrophilic solvent; the plasticizer is at least one of dioctyl phthalate, dibutyl phthalate, dioctyl terephthalate, and epoxidized soybean oil; the nucleating agent is at least one of diatomaceous earth or nano-silica; and the stabilizer is a calcium-zinc composite stabilizer.

7. A method for preparing a PVC conveyor belt surface layer with high wear resistance as described in any one of claims 1-6, characterized in that, The preparation method of the PVC conveyor belt surface material includes the following steps: adding PVC paste resin, SBR emulsion, BR emulsion and maleic anhydride grafted polyethylene into a mixer, and stirring for 30-60 minutes at a temperature of 35-45℃ and a speed of 500-1500rpm to form PVC surface paste. The PVC surface paste is cured to form the PVC conveyor belt surface layer. The curing conditions are: first, dry at 40-60℃ for 30-60 minutes, then raise the temperature to 100-120℃ and dry for 10-30 minutes.

8. A lightweight conveyor belt having a fabric skeleton and a surface layer coated on the fabric skeleton, characterized in that, The surface layer is the PVC conveyor belt surface layer according to any one of claims 1-6, and the curing conditions of the surface layer are to first dry at 40-60℃ for 30-60 minutes, and then heat up to 100-120℃ and dry for 10-30 minutes.

9. The lightweight conveyor belt according to claim 8, characterized in that, The surface layer is applied to the surface of the fabric skeleton by scraping or rolling, with a coating thickness of 1-5 mm.

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