Low-cost rubber for blasting and its preparation method and application

Abstract

The application belongs to the technical field of rubber, and particularly relates to a low-cost rubber for blasting, a preparation method and application thereof. The rubber formula comprises the following raw materials in parts by weight: 100 parts of tread reclaimed rubber, 2-4 parts of white carbon black, 20-40 parts of nano calcium carbonate, 2-4 parts of zinc oxide, 2-3 parts of modified polyester fiber, 0.5-1.2 parts of paraffin, 2-4 parts of stearic acid, 1-2 parts of antioxidant, 0.5-1.7 parts of accelerator, and 1-3 parts of sulfur. The rubber for blasting uses reclaimed rubber as raw material, and the comprehensive performance of the obtained rubber is excellent, the cost is low, the rubber for blasting is used to manufacture a mine blasting rubber isolator, the shortage of natural rubber can be relieved, the reclaimed resources are fully utilized, the environmental pollution is reduced, and the rubber has wide economic value and social value.

Description

Technical Field

[0001] This invention belongs to the field of rubber technology, specifically relating to a low-cost blasting rubber, its preparation method, and its application. Background Technology

[0002] The natural degradation process of rubber products is very long. Waste rubber causes black pollution, which is more difficult to deal with than plastic pollution (white pollution). At the same time, it seriously wastes precious rubber resources. Therefore, properly handling waste rubber is of great practical significance for making full use of recycled resources, reducing environmental pollution, and improving the living environment.

[0003] Reclaimed rubber is a type of rubber with a certain degree of plasticity that can be reused, processed from waste rubber products. Reclaimed rubber is an important raw material for the rubber industry. On the one hand, it can replace natural rubber, alleviating the severe shortage of natural rubber and serving as an important measure to address the environmental pollution caused by waste rubber. On the other hand, reclaimed rubber is inexpensive, giving reclaimed rubber products a significant cost advantage. Rubber isolators for blasting can improve blasting effectiveness and efficiency. Since blasting rubber isolators are disposable products, using reclaimed rubber to make them is not only environmentally friendly but also cost-effective. However, reclaimed rubber has some drawbacks. Its weather resistance, flexural strength, compression set, tensile strength, and tear resistance are relatively poor, and reclaimed rubber products may suffer from wear and aging due to insufficient strength. Therefore, developing a technology that can produce high-performance blasting rubber isolators using only reclaimed rubber by optimizing raw material ratios is of great significance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a low-cost blasting rubber, its preparation method, and its application. This blasting rubber uses fully recycled rubber as raw material, resulting in rubber with excellent comprehensive performance and low cost. It can be used to manufacture rubber isolators for mining blasting, which can alleviate the scarcity of natural rubber, make full use of recycled resources, reduce environmental pollution, and has broad economic and social value.

[0005] To achieve the above objectives, the present invention provides a low-cost blasting rubber, wherein the rubber formulation comprises the following raw materials in parts by weight:

[0006] 100 parts of tread reclaimed rubber, 2-4 parts of silica, 20-40 parts of nano-calcium carbonate, 2-4 parts of zinc oxide, 2-3 parts of modified polyester fiber, 0.5-1.2 parts of paraffin wax, 2-4 parts of stearic acid, 1-2 parts of antioxidant, 0.5-1.7 parts of accelerator, and 1-3 parts of sulfur.

[0007] This technical solution uses reclaimed tread rubber as raw material. By optimizing the additive composition, the weather resistance, aging resistance, flexural strength, tensile strength, and tear resistance of the reclaimed tread rubber can be effectively improved, resulting in good resilience and wear resistance. Specifically, adding a small amount of silica can improve the physical and mechanical properties, wear resistance, and flexural crack resistance of the rubber products; adding a certain amount of nano-calcium carbonate improves dispersibility, enhances wear resistance, tear resistance, and aging resistance, and improves the processing performance of the rubber; adding zinc oxide as an activator improves vulcanization efficiency, reduces the amount of accelerator used, and acts as a reinforcing agent to improve the rubber's corrosion resistance and aging resistance, while also increasing elasticity; adding a certain amount of modified polyester fiber increases the rubber's impact resistance and flexural strength, resulting in good strength, resilience, and stability; adding paraffin wax forms a protective layer on the rubber surface to prevent ozone cracking and improve aging resistance; and adding stearic acid improves the processability of the rubber compound, promotes raw material dispersion, and synergistically promotes vulcanization with zinc oxide.

[0008] Furthermore, in the above technical solution, the preparation method of the modified polyester fiber is as follows: after pulverizing the polyester fiber, it is placed in a water-soluble epoxy resin solution, an appropriate amount of sodium hydroxide solution is added, and it is impregnated under ultrasonic conditions for 50-80 minutes. After cleaning and drying, it is then impregnated with phenolic resin latex for 15-20 minutes, dried, and cured to obtain the modified polyester fiber. Polyester fiber has characteristics such as high tensile strength, low elongation at constant load, small deformation, good impact resistance and heat resistance, and low water absorption. However, its bonding with rubber is relatively difficult. In this technical solution, polyester fibers are modified under certain conditions. First, they are combined with an epoxy resin solution. The epoxy groups react with the active groups such as ester groups, hydroxyl groups, and carboxyl groups on the surface of the polyester fibers to form stable chemical bonds. Hydroxyl groups also form hydrogen bonds with the carbonyl groups on the surface of the polyester fibers, which can increase the adhesion between the polyester fibers and the resin. Then, phenolic resin latex is used to further treat the polyester fibers. The active functional groups such as phenolic hydroxyl groups and aldehyde groups in the phenolic resin molecules react further with the hydroxyl groups on the surface of the polyester fibers. At the same time, they can fill the micropores of the fibers, improving the fiber strength and wear resistance, while further improving the adhesion and stability between the polyester fibers and rubber.

[0009] Furthermore, in the above technical solution, the length of the polyester fiber is <10mm.

[0010] Furthermore, in the above technical solution, the concentration of epoxy resin in the water-soluble epoxy resin solution is 50-80 g / L; the ultrasonic frequency is 10-15 kHz; and the impregnation temperature is 70-85℃.

[0011] Furthermore, in the above technical solution, the mass ratio of phenolic resin:water:latex in the phenolic resin latex is 1-4:15-25:15-30.

[0012] Furthermore, in the above technical solution, the particle size of the silica is 150-200 nm, and its specific surface area is 20-30 m². 2 / g; The antioxidant is a mixture of antioxidant D (N-phenyl-2-naphthylamine) and antioxidant 2246 (antioxidant 2246) in a mass ratio of 1:1-3. In this technical solution, ultra-low specific surface area silica is selected as a reinforcing agent, which can not only replace ordinary carbon black but also improve processing performance and resistance to flexural cracking. Antioxidant D is an amine antioxidant, possessing heat resistance, oxidation resistance, ozone resistance, and protection against copper ions and flexural inertia, but it is prone to discoloration upon exposure to light. Antioxidant 2246 is a phenolic antioxidant, characterized by non-discoloration and non-polluting properties, and it has good protective efficacy against heat, oxygen, metal ion aging, and sunlight aging. This invention combines the advantages of both, using the two antioxidants in combination to greatly improve the weather resistance and anti-aging properties of rubber, extending its service life.

[0013] Furthermore, in the above technical solution, the accelerator is a mixture of accelerator DM (dibenzothiazole disulfide) and accelerator TMTD (tetramethylthiuram dithiosulfate) in a mass ratio of 0.5-1.5 : 0.05-0.15. Accelerator DM is a thiazole accelerator, and accelerator TMTD is a thiuram accelerator. The combination of the two can improve activity, thereby improving vulcanization efficiency, improving the mechanical properties of vulcanized rubber, and requiring less dosage.

[0014] This invention also provides a low-cost method for preparing blasting rubber, comprising the following steps:

[0015] (1) Weigh each raw material according to the weight proportions of each component in the formula and set aside;

[0016] (2) The tread reclaimed rubber is placed in a steam explosion tank for explosion treatment to obtain pretreated tread reclaimed rubber;

[0017] (3) Set the rolling temperature of the open mill to 45-50℃. When the rolling temperature exceeds 50℃, introduce water at 20-25℃ to reduce the rolling temperature. Then put the pretreated tread reclaimed rubber into the open mill and start milling for 3-4 minutes, passing through the mill 4-6 times during the process.

[0018] (4) Add paraffin wax and stearic acid to the open mill and mix for 3-4 minutes;

[0019] (5) Add the modified polyester fiber to the open mill and mix for 5-6 minutes;

[0020] (6) Add antioxidant, zinc oxide and accelerator to the open mill and mix for 2-3 minutes;

[0021] (7) Add nano-calcium carbonate and carbon black to a two-roll mill and mix for 3-4 minutes;

[0022] (8) Add sulfur to the open mill and mix for 6-7 minutes, making triangular clumps 3-4 times during the process to obtain the compound rubber;

[0023] (9) Pass the compound rubber through a thin tube 3-5 times and then cut it into sheets.

[0024] Furthermore, in step (2) of the above technical solution, the conditions for steam explosion are: pressure 6-8 MPa, and pressure maintenance time 120-150 s. In this technical solution, the tabletop recycled rubber is pretreated by steam explosion. During the steam explosion process, high-temperature steam can uniformly preheat the rubber particles, so that the rubber liquid maintains a high viscosity when melting, thereby increasing the rubber content of the rubber products and enhancing the rubber resilience; at the same time, it can improve the internal structure of the rubber, reduce cracking and peeling caused by uneven heating or stress concentration, and improve the durability of the rubber products.

[0025] The present invention also provides an application of the above-mentioned low-cost blasting rubber in a rubber isolator for mining blasting.

[0026] The beneficial effects of this invention are:

[0027] This invention uses reclaimed tread rubber as raw material. By optimizing the composition ratio of additives and the preparation process, it can effectively improve the weather resistance, aging resistance, flexural strength, tensile strength, and tear resistance of the reclaimed tread rubber, resulting in good resilience, wear resistance, and significantly reduced costs. When used to prepare rubber isolators for mining blasting, it not only has excellent performance but also alleviates the severe shortage of natural rubber. It is an important measure to solve the environmental pollution caused by waste rubber and has profound practical significance for making full use of recycled resources, reducing environmental pollution, and improving the living environment. It has broad economic and social value. Detailed Implementation

[0028] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the raw materials used in the following examples are all commercially available products and can be purchased from the market.

[0029] All preparation processes not specifically described in this invention are conventional processes.

[0030] The present invention will be further described in detail below with reference to embodiments:

[0031] Example 1

[0032] A method for preparing low-cost blasting rubber includes the following steps:

[0033] (1) Weigh each raw material according to the weight proportions of each component in the formula: 100 parts of tread reclaimed rubber, 2 parts of silica, 40 parts of nano-calcium carbonate, 2 parts of zinc oxide, 2 parts of modified polyester fiber, 1.2 parts of paraffin wax, 2 parts of stearic acid, 1 part of antioxidant, 1.7 parts of accelerator, and 1 part of sulfur; wherein, the particle size of silica is 150-200 nm and its specific surface area is 20 m². 2 / g; the antioxidant is a mixture of antioxidant D and antioxidant 2246 in a mass ratio of 1:1; the accelerator is a mixture of accelerator DM and accelerator TMTD in a mass ratio of 0.5:0.05; the modification method of the modified polyester fiber is as follows: after the polyester fiber is crushed to a length <10mm, it is placed in a solution with an epoxy resin concentration of 50g / L, an appropriate amount of 5% hydroxide solution is added to make the solution alkaline, and it is immersed in ultrasonic conditions at a temperature of 85℃ and a frequency of 15kHz for 50min. After cleaning and drying, it is then immersed in phenolic resin latex (phenolic resin: water: latex in a mass ratio of 1:15:15) for 20min, dried and cured to obtain the modified polyester fiber.

[0034] (2) The tread reclaimed rubber was placed in a steam explosion tank with a pressure of 6 MPa and maintained for 150 seconds for explosion treatment to obtain pretreated tread reclaimed rubber.

[0035] (3) Set the rolling temperature of the open mill to 45-50℃. When the rolling temperature exceeds 50℃, introduce water at 20-25℃ to reduce the rolling temperature. Then put the pretreated tread reclaimed rubber into the open mill and start milling for 3 minutes, during which time it is passed through the mill 6 times.

[0036] (4) Add paraffin wax and stearic acid to the open mill and mix for 3 minutes;

[0037] (5) Add the modified polyester fiber to the open mill and mix for 5 minutes;

[0038] (6) Add antioxidant, zinc oxide and accelerator to open mill and mix for 2 minutes;

[0039] (7) Add nano-calcium carbonate and carbon black to a two-roll mill and mix for 3 minutes;

[0040] (8) Add sulfur to the open mill and mix for 7 minutes, making triangular bags 4 times during the process to obtain the compound rubber;

[0041] (9) Pass the compound rubber through a thin tube 5 times and then cut it into sheets.

[0042] Example 2

[0043] A method for preparing low-cost blasting rubber includes the following steps:

[0044] (1) Weigh each raw material according to the weight proportions of each component in the formula: 100 parts of tread reclaimed rubber, 3 parts of silica, 30 parts of nano-calcium carbonate, 3 parts of zinc oxide, 2.5 parts of modified polyester fiber, 1 part of paraffin wax, 3 parts of stearic acid, 1.5 parts of antioxidant, 1 part of accelerator, and 2 parts of sulfur; wherein, the particle size of silica is 150-200 nm, and its specific surface area is 20-30 m². 2 / g; the antioxidant is a mixture of antioxidant D and antioxidant 2246 in a mass ratio of 1:2; the accelerator is a mixture of accelerator DM and accelerator TMTD in a mass ratio of 1:0.15; the modification method of the modified polyester fiber is as follows: after crushing the polyester fiber to a length <10mm, put it into a solution with an epoxy resin concentration of 60g / L, add an appropriate amount of 5% hydroxide solution to make the solution alkaline, and impregnate it under ultrasonic conditions at a temperature of 80℃ and a frequency of 12kHz for 60min. After cleaning and drying, impregnate it with phenolic resin latex (phenolic resin: water: latex in a mass ratio of 3:20:20) for 15-20min, dry and cure to obtain the modified polyester fiber.

[0045] (2) The tread reclaimed rubber was placed in a steam explosion tank with a pressure of 7 MPa and maintained for 130 seconds for explosion treatment to obtain pretreated tread reclaimed rubber.

[0046] (3) Set the rolling temperature of the open mill to 45-50℃. When the rolling temperature exceeds 50℃, introduce water at 20-25℃ to reduce the rolling temperature. Then put the pretreated tread reclaimed rubber into the open mill and start milling for 3.5 minutes, during which the rubber is passed through 5 times.

[0047] (4) Add paraffin wax and stearic acid to the open mill and mix for 3.5 min;

[0048] (5) Add the modified polyester fiber to the open mill and mix for 5.5 min;

[0049] (6) Add antioxidant, zinc oxide and accelerator to the open mill and mix for 2.5 min;

[0050] (7) Add nano-calcium carbonate and carbon black to a two-roll mill and mix for 3.5 min;

[0051] (8) Add sulfur to the open mill and mix for 6.5 minutes, making three triangular clumps during the process to obtain the mixed rubber;

[0052] (9) Pass the compound rubber through a thin tube 4 times and then cut it into sheets.

[0053] Example 3

[0054] A method for preparing low-cost blasting rubber includes the following steps:

[0055] (1) Weigh each raw material according to the weight proportions of each component in the formula: 100 parts of tread reclaimed rubber, 4 parts of silica, 20 parts of nano-calcium carbonate, 4 parts of zinc oxide, 3 parts of modified polyester fiber, 0.5 parts of paraffin wax, 4 parts of stearic acid, 2 parts of antioxidant, 0.5 parts of accelerator, and 3 parts of sulfur; wherein, the particle size of silica is 150-200 nm and its specific surface area is 20-30 m². 2 / g; the antioxidant is a mixture of antioxidant D and antioxidant 2246 in a mass ratio of 1:3; the accelerator is a mixture of accelerator DM and accelerator TMTD in a mass ratio of 1.5:0.1; the modification method of the modified polyester fiber is as follows: after the polyester fiber is crushed to a length <10mm, it is placed in an epoxy resin solution with a concentration of 80g / L, an appropriate amount of 5% hydroxide solution is added to make the solution alkaline, and it is immersed in ultrasonic conditions at a temperature of 70℃ and a frequency of 10kHz for 80min. After cleaning and drying, it is then immersed in phenolic resin latex (phenolic resin: water: latex in a mass ratio of 4:25:30) for 15min, dried and cured to obtain the modified polyester fiber.

[0056] (2) The tread reclaimed rubber was placed in a steam explosion tank with a pressure of 8MPa and maintained for 120s for explosion treatment to obtain pretreated tread reclaimed rubber.

[0057] (3) Set the rolling temperature of the open mill to 45-50℃. When the rolling temperature exceeds 50℃, introduce water at 20-25℃ to reduce the rolling temperature. Then put the pretreated tread reclaimed rubber into the open mill and start milling for 4 minutes, passing through it 4 times during the process.

[0058] (4) Add paraffin wax and stearic acid to the open mill and mix for 4 minutes;

[0059] (5) Add the modified polyester fiber to the open mill and mix for 6 minutes;

[0060] (6) Add antioxidant, zinc oxide and accelerator to open mill and mix for 3 minutes;

[0061] (7) Add nano-calcium carbonate and carbon black to a two-roll mill and mix for 4 minutes;

[0062] (8) Add sulfur to the open mill and mix for 6 minutes, making three triangular bags during the process to obtain the mixed rubber;

[0063] (9) Pass the rubber compound through a thin tube 3 times and then sheet it.

[0064] Comparative Example 1

[0065] A method for preparing low-cost blasting rubber, which differs from Example 2 in that it uses ordinary polyester fiber, but is otherwise the same as Example 2.

[0066] Comparative Example 2

[0067] A method for preparing low-cost blasting rubber, which differs from Example 2 in that modified polyester fiber is not added, but otherwise the same as Example 2.

[0068] Comparative Example 3

[0069] A method for preparing low-cost blasting rubber, differing from Example 2 in that it uses ordinary carbon black with a specific surface area of ​​150 m². 2 / g, the rest is the same as in Example 2.

[0070] Comparative Example 4

[0071] A method for preparing low-cost blasting rubber, which differs from Example 2 in that the antioxidant is a single antioxidant D, while the rest is the same as in Example 2.

[0072] Comparative Example 5

[0073] A method for preparing low-cost blasting rubber, which differs from Example 2 in that the antioxidant is a single antioxidant 2246, while the rest is the same as in Example 2.

[0074] Comparative Example 6

[0075] A method for preparing low-cost blasting rubber, which differs from Example 2 in that the accelerator is a single accelerator DM, while the rest is the same as in Example 2.

[0076] Comparative Example 7

[0077] A method for preparing low-cost blasting rubber, which differs from Example 2 in that the accelerator is a single accelerator TMTD, while the rest is the same as in Example 2.

[0078] Comparative Example 8

[0079] A method for preparing low-cost blasting rubber, which differs from Example 2 in that step (2) is omitted, while the rest is the same as in Example 2.

[0080] The compound rubbers prepared in Examples 1-3 and Comparative Examples 1-8 were vulcanized into 2.0 mm sheets using a flat vulcanizing apparatus at a vulcanizing temperature of 143°C for 3 min. Their relevant properties were then tested, including hardness (GB / T531), mechanical properties (including tensile strength, elongation at break, and tear strength) (GB / T 528), resilience (GB / T 1681), aging resistance (GB3512), compression set (GB / T 7759), abrasion resistance (GB / T1689), and ozone resistance (GB / T7762). The results are shown in Tables 1 and 2.

[0081] Table 1 Performance test results of Examples 1-3

[0082]

[0083] Table 2 Performance test results of Comparative Examples 1-8

[0084]

[0085] As can be seen from the results in Table 1, the compound obtained by the formulation and preparation method of the present invention has excellent hardness, tensile strength, resilience, compression set, abrasion resistance and weather resistance, and has excellent overall performance. It can be used to make rubber isolators for mining blasting.

[0086] As can be seen from the results in Table 2, the performance of Comparative Example 1 was affected by the use of ordinary polyester fiber, possibly due to its poor bonding with the reclaimed tread rubber, which affected its overall performance. Comparative Example 2, without the addition of polyester fiber, had even worse overall performance, especially poor resilience. Comparative Example 3 used ordinary high specific surface area carbon black, which, although it also had a reinforcing effect, was less effective than low specific surface area silica. In Comparative Examples 4-5, the use of only antioxidant D or antioxidant 2246 resulted in a decrease in both anti-aging and ozone properties, indicating a synergistic effect between the two. Similarly, in Comparative Examples 6-7, the use of only accelerator DM or accelerator TMTD also led to a decrease in overall performance. In Comparative Example 8, the lack of pre-treatment with steam explosion for the reclaimed tread rubber during preparation significantly reduced its overall performance, indicating that pre-treatment with steam explosion before mixing can improve the rubber's resilience, aging resistance, and crack resistance.

[0087] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. 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 low-cost blasting rubber, characterized in that, The rubber formulation comprises the following raw materials in parts by weight: 100 parts of tread reclaimed rubber, 2-4 parts of silica, 20-40 parts of nano-calcium carbonate, 2-4 parts of zinc oxide, 2-3 parts of modified polyester fiber, 0.5-1.2 parts of paraffin wax, 2-4 parts of stearic acid, 1-2 parts of antioxidant, 0.5-1.7 parts of accelerator, and 1-3 parts of sulfur; The tread reclaimed rubber is subjected to steam explosion treatment before open mixing, wherein the treatment pressure is 6-8MPa and the pressure is maintained for 120-150s. The modified polyester fiber is prepared by: crushing the polyester fiber, placing it in a water-soluble epoxy resin solution, adding an appropriate amount of sodium hydroxide solution, impregnating it under ultrasonic conditions for 50-80 minutes, cleaning and drying it, then impregnating it with phenolic resin latex for 15-20 minutes, drying and curing it to obtain the modified polyester fiber. The precipitated silica has a particle size of 150-200 nm and a specific surface area of ​​20-30 m². 2 / g; The antioxidant is a mixture of antioxidant D and antioxidant 2246 in a mass ratio of 1:1-3; The accelerator is a mixture of accelerator DM and accelerator TT in a mass ratio of 0.5-1.5 : 0.05-0.

15.

2. The low-cost blasting rubber according to claim 1, characterized in that, The length of the polyester fiber is <10mm.

3. The low-cost blasting rubber according to claim 1, characterized in that, The concentration of epoxy resin in the water-soluble epoxy resin solution is 50-80 g / L; the ultrasonic frequency is 10-15 kHz; and the impregnation temperature is 70-85℃.

4. A method for preparing low-cost blasting rubber as described in any one of claims 1-3, characterized in that, Includes the following steps: (1) Weigh each raw material according to the weight proportions of each component in the formula and set aside; (2) The tread reclaimed rubber is placed in a steam explosion tank for explosion treatment to obtain pretreated tread reclaimed rubber; (3) Set the rolling temperature of the open mill to 45-50℃. When the rolling temperature exceeds 50℃, introduce water at 20-25℃ to reduce the rolling temperature. Then put the pretreated tread reclaimed rubber into the open mill and start milling for 3-4 minutes, passing through the mill 4-6 times during the process. (4) Add paraffin wax and stearic acid to the open mill and mix for 3-4 minutes; (5) Add the modified polyester fiber to the open mill and mix for 5-6 minutes; (6) Add antioxidant, zinc oxide and accelerator to the open mill and mix for 2-3 minutes; (7) Add nano-calcium carbonate and carbon black to a two-roll mill and mix for 3-4 minutes; (8) Add sulfur to the open mill and mix for 6-7 minutes, making triangular clumps 3-4 times during the process to obtain the compound rubber; (9) Pass the compound rubber through a thin tube 3-5 times and then cut it into sheets.

5. The preparation method according to claim 4, characterized in that, In step (2), the conditions for steam explosion are: pressure 6-8 MPa, and pressure maintenance time 120-150 s.

6. The application of a low-cost blasting rubber as described in any one of claims 1-3 or a low-cost blasting rubber prepared by the preparation method as described in any one of claims 4-5 in a rubber isolator for mining blasting.

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