Heat-conducting rubber material and rubber track

Abstract

The present invention relates to a thermally conductive rubber material and a rubber track. The preparation method of the rubber material comprises the steps of mixing a raw material composition; wherein, by weight, the raw material composition comprises: 100 parts of a rubber raw material; 20-30 parts of carbon fibers subjected to a first pretreatment; 25-35 parts of hexagonal boron nitride powder subjected to a second pretreatment; and 25-35 parts of nano powder subjected to a third pretreatment; wherein the average length of the carbon fibers is 3 mm to 10 mm; wherein the average particle size of the hexagonal boron nitride powder is 10 μm to 200 μm; wherein the average particle size of the nano powder is 5 nm to 100 nm, and the nano powder is selected from one or more of metal powder and metal oxide powder; wherein the first pretreatment comprises treating the carbon fibers with a silane coupling agent and then etching with CO2 plasma; wherein the second pretreatment comprises treating the hexagonal boron nitride powder with a silane coupling agent; and wherein the third pretreatment comprises treating the nano powder with a solution containing octadecylamine and stearic acid.

Description

Technical Field

[0001] The present invention relates to the field of materials, and in particular to a heat-conducting rubber material and a rubber track. Background Art

[0002] Rubber tracks are widely used in tracked vehicles, especially in construction machinery, agricultural machinery, military machinery and equipment. With the development of industrialization, people's requirements for rubber tracks are getting higher and higher. Rubber tracks are developing in the direction of diversification and complete specifications.

[0003] Compared with metal tracks, the main advantage of rubber tracks is their high speed. However, a major problem associated with high speed is that rubber tracks generate a lot of heat, and the heat generated is not easily conducted away, causing the rubber tracks to overheat, age severely, shorten their lifespan, and also cause phenomena such as chipping, breaking, and bulging.

[0004] There are two main reasons for heat generation in rubber tracks. One is external: friction between the track and the drive wheel, and between the track and the ground, generates a large amount of heat. The other is internal: when a rubber track contracts under pressure or stretches under tension, the external forces acting on it are used to overcome the internal friction resistance of the rubber molecular segments, which is converted into heat within the rubber. Rubber is a poor conductor of heat, with a thermal conductivity of only 0.25W / m·K. Because the generated heat is difficult to dissipate, it accelerates the thermal aging of the track and reduces its service life. Summary of the Invention

[0005] The inventors have discovered that in order to obtain a rubber track with a long service life, it is necessary to provide a rubber material with good thermal conductivity and mechanical properties.

[0006] The inventors have designed a high thermal conductivity rubber material formula, which has the following advantages:

[0007] 1) Good thermal conductivity;

[0008] 2) Moderate hardness;

[0009] 3) Good tensile strength;

[0010] 4) Low compression set.

[0011] In some aspects, the present disclosure provides a method for preparing a rubber material, comprising the steps of mixing a raw material composition;

[0012] Wherein, the raw material composition comprises, by weight:

[0013] 100 parts of rubber raw materials;

[0014] 20-30 parts (e.g., 23-27 parts) of first pretreated carbon fibers;

[0015] 25-35 parts (e.g., 27-32 parts) of hexagonal boron nitride powder that has undergone a second pretreatment;

[0016] 25-35 parts (e.g., 28-32 parts) of the third pretreated nanopowder;

[0017] Wherein, the average length of the carbon fibers is 3 mm to 10 mm (e.g., 6 to 8 mm);

[0018] Wherein, the average particle size of the hexagonal boron nitride powder is 10 μm to 200 μm (e.g., 80 to 120 μm);

[0019] The nanopowder has an average particle size of 5 nm to 100 nm (e.g., 40 nm to 60 nm), and the nanopowder is selected from one or more of metal powder and metal oxide powder;

[0020] Wherein, the first pretreatment includes treating the carbon fiber with a silane coupling agent (such as KH-550) and then etching with CO2 plasma;

[0021] Wherein, the second pretreatment comprises treating the hexagonal boron nitride powder with a silane coupling agent;

[0022] Wherein, the third pretreatment comprises treating the nano powder with a solution containing octadecylamine and stearic acid.

[0023] Treating hexagonal boron nitride powder with a silane coupling agent refers to treating hexagonal boron nitride powder with a silane coupling agent solution. The solute of the silane coupling agent solution is silane coupling agent (KH-550), the solvent is white oil, and the KH-550 content is 20%.

[0024] Treating carbon fibers with a silane coupling agent refers to treating the carbon fibers with a silane coupling agent solution. The solute of the silane coupling agent solution is the silane coupling agent (KH-550), the solvent is white oil, and the KH-550 content is 20%.

[0025] In some embodiments, the CO2 plasma etching treatment time is 10 to 30 minutes.

[0026] In some embodiments, CO2 plasma etching can achieve one or more of the following effects: cleaning the carbon fiber surface, deepening the grooves on the carbon fiber surface and increasing the surface roughness, and introducing active groups, such as -C=O, on the carbon fiber surface.

[0027] The inventors discovered that the specific ratio of carbon fiber, hexagonal boron nitride powder, and nanopowder described above significantly improves the thermal conductivity and mechanical properties of the rubber material. Furthermore, the specific first, second, and third pretreatments are essential; only after these specific pretreatments can the three components coexist in the rubber in a coordinated and synergistic manner. The inventors discovered that even if carbon fiber, hexagonal boron nitride powder, and nanopowder that have not undergone these pretreatments are added to the rubber, they do not achieve the significantly improved technical effects of the present disclosure.

[0028] In some embodiments, the rubber raw material contains natural rubber and butadiene rubber, and the weight ratio of natural rubber to butadiene rubber is 70-95 (eg, 80-90):5-30 (eg, 10-20).

[0029] In some embodiments, the silane coupling agent includes one or more of a titanate silane coupling agent and an aluminate silane coupling agent.

[0030] In some embodiments, the nanopowder is selected from one or more of nano-aluminum powder, nano-aluminum oxide powder, nano-copper powder, and nano-zinc oxide powder.

[0031] In some embodiments, the nanopowder is nanocopper powder.

[0032] In some embodiments, the solution containing octadecylamine and stearic acid is a chloroform solution containing octadecylamine and stearic acid.

[0033] In some embodiments, the treatment is a surface treatment.

[0034] In some embodiments, the first pretreatment involves placing the carbon fibers in a high-speed mixer and adding a white oil solution of a silane coupling agent (such as KH-550) dropwise while stirring at high speed. After completion, the carbon fibers are removed from the mixer and dried in an oven at 50°C, followed by a CO2 plasma etching treatment for 20 minutes. The silane coupling agent content in the white oil solution can be 15-25% by weight, for example, 20% by weight.

[0035] In some embodiments, hexagonal boron nitride powder is pretreated by placing the hexagonal boron nitride in a high-speed mixer and adding a white oil solution of a silane coupling agent (such as KH-550) dropwise while stirring at high speed. After completion, the powder is removed from the mixer and dried in an oven at 50°C. The silane coupling agent content in the white oil solution can be 15-25 wt%, for example, 20 wt%.

[0036] In some embodiments, 0.5 to 3 parts, for example 1 part, of the silane coupling agent is applied per 100 parts by weight of the carbon fibers.

[0037] In some embodiments, 0.5 to 3 parts, for example 1 part, of the silane coupling agent is applied per 100 parts by weight of the hexagonal boron nitride powder.

[0038] In some embodiments, the feedstock composition further comprises:

[0039] 1-5 parts (e.g. 2-3 parts) of vulcanizing agent (e.g. sulfur);

[0040] 1-5 parts paraffin wax (e.g. 2-3 parts);

[0041] 1 to 5 parts (e.g., 2 to 3 parts) of stearic acid.

[0042] In some embodiments, the feedstock composition further comprises:

[0043] 2~5 parts of antioxidant (e.g. 2~3 parts);

[0044] 1~5 parts of accelerator (for example 2~3 parts).

[0045] In some embodiments, the accelerator is selected from one or more of thiuram accelerators and sulfenamide accelerators.

[0046] In some embodiments, the feedstock composition further comprises:

[0047] 1-10 parts of micron zinc oxide powder;

[0048] 30-60 parts of carbon black powder;

[0049] Wherein, the average particle size of the micron zinc oxide powder is 0.5 to 1.5 microns, for example, 1 micron;

[0050] The apparent density of the carbon black powder is 0.3-0.4 g / cm 3 , for example 0.34~0.35 g / cm 3 .

[0051] In some embodiments, the feedstock composition comprises:

[0052] 90~100 parts of natural rubber

[0053] 4~6 parts of butadiene rubber

[0054] 1.5-2 parts sulfur

[0055] 0.8~1.2 parts paraffin

[0056] 1-2 parts of stearic acid

[0057] Antioxidant 4040 1~2 parts

[0058] Antioxidant D 1~2 parts

[0059] Accelerator CZ 0.5~1 part

[0060] Accelerator TMTD 0.8~1.2 parts

[0061] 3~5 parts zinc oxide powder

[0062] 40~50 parts of carbon black powder

[0063] 23~27 parts of carbon fiber

[0064] 28-32 parts hexagonal boron nitride powder

[0065] 28~32 parts of nano powder.

[0066] In some embodiments, the feedstock composition comprises:

[0067] 95 parts of natural rubber

[0068] 5 parts of butadiene rubber

[0069] 1.8 parts sulfur

[0070] 1 part paraffin

[0071] 1.5 parts of stearic acid

[0072] 1.5 parts of antioxidant 4040

[0073] 1.5 parts of antioxidant D

[0074] Accelerator CZ 0.8 parts

[0075] 1 part of TMTD accelerator

[0076] 4 parts zinc oxide powder

[0077] 45 parts of carbon black powder

[0078] 25 parts of carbon fiber

[0079] 30 parts hexagonal boron nitride powder

[0080] 30 parts of nano powder.

[0081] In some embodiments, the method for preparing the rubber material includes: using a rubber mixer to roll-mold the rubber raw material, adding other components of the raw material composition except the vulcanizer, mixing, and performing vulcanization after mixing.

[0082] In some embodiments, the roller temperature of the rubber mixer is controlled to be 45-55°C during the mixing process.

[0083] In some aspects, a rubber material is provided, which is prepared by any of the methods described above.

[0084] In some embodiments, any of the rubber materials described above has one or more of the following properties:

[0085] The thermal conductivity is 3-3.5 W / m·K. Optionally, the thermal conductivity is measured according to the hot wire method in GB / T 11205-2009-Rubber-Determination of thermal conductivity;

[0086] The tensile strength is 20-22 MPa. Optionally, the tensile strength is determined according to GB / T528-2009 Vulcanized rubber or thermoplastic rubber - Determination of stress, strain and deformation energy;

[0087] The hardness is 70-80HA. Optionally, the hardness is measured according to GB / T531.1-2008, Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness.

[0088] The compression set is 6~7%. Alternatively, GB / T 7759.1-2015 Vulcanized rubber or thermoplastic rubber - Determination of compression set - Part 1: Determination at room temperature and elevated temperature conditions.

[0089] In some aspects, a rubber track is made of the rubber material provided by any of the above embodiments.

[0090] Terminology Notes:

[0091] If the present invention uses the following terms, they may have the following meanings:

[0092] Various relative terms, such as "front," "back," "top," and "bottom," "upper," "lower," "above," and "below," may be used to facilitate the description of various embodiments. Relative terms are defined with respect to a structure's conventional orientation and do not necessarily indicate an actual orientation of the structure when manufactured or used. Therefore, the following detailed description should not be construed in a limiting sense. As used in the description and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0093] "Containing" means a content of 10% or more, for example, 20% or more, for example, 30% or more, for example, 40% or more, for example, 50% or more, for example, 60% or more, for example, 70% or more, for example, 80% or more, for example, 90% or more, for example, 100%. When the content is 100%, "containing" means the same as "consisting of..."

[0094] Beneficial effects

[0095] One or more technical solutions disclosed herein have one or more of the following beneficial effects:

[0096] 5) Good thermal conductivity;

[0097] 6) Moderate hardness;

[0098] 7) Good tensile strength;

[0099] 8) Low compression set. DETAILED DESCRIPTION

[0100] The embodiments of the present invention will be described in detail below with reference to the examples, but it will be understood by those skilled in the art that the following examples are merely illustrative of the present invention and should not be construed as limiting the scope of the invention. Where specific conditions are not specified in the examples, the methods were performed according to conventional conditions or the conditions recommended by the manufacturer. Where the manufacturers of the reagents or instruments are not specified, they are all commercially available conventional products.

[0101] Example 1

[0102] Rubber raw material ratio:

[0103] The rubber preparation process includes:

[0104] Carbon fiber pretreatment: Place the carbon fibers in a high-speed mixer and add a white oil solution of KH-550 (20 wt% KH-550) dropwise while stirring. Apply 1 part KH-550 (calculated as neat KH-550) per 100 parts of carbon fiber. Remove the fibers and dry them in an oven at 50°C. Etch them with CO2 plasma for 20 minutes.

[0105] Pretreatment of hexagonal boron nitride powder: Place the hexagonal boron nitride in a high-speed mixer and add a white oil solution of KH-550 (20 wt% KH-550) dropwise while stirring. Add 1 part KH-550 (calculated as neat KH-550) per 100 parts hexagonal boron nitride powder. Once finished, remove the mixture and dry it in an oven at 50°C.

[0106] Nanopowder (ie, nanocopper powder) pretreatment: the nanocopper powder was immersed in a chloroform solution containing octadecylamine (1.5 wt %) and stearic acid (1.5 wt %).

[0107] (1) Put the raw rubber into an open rubber mixer and plasticize for 10 minutes. Then gradually add other raw materials weighed according to the weight ratio to prepare a rubber mixture.

[0108] (2) Leave the rubber mixture at room temperature for 12 hours.

[0109] (3) The vulcanization conditions of the rubber mix are: pressure 15~30MPa, temperature 135~145℃.

[0110] Comparative Example 1 (D1)

[0111] Compared with Example 1, the additive is only pretreated carbon fiber, and the content is 25 parts.

[0112] Comparative Example 2 (D2)

[0113] Compared with Example 1, the additive is only pretreated hexagonal boron nitride, and the content is 30 parts.

[0114] Comparative Example 3 (D3)

[0115] Compared with Example 1, the additive is only pretreated nano copper powder, and the content is 30 parts.

[0116] Analysis and testing:

[0117] According to "GB / T 11205-2009 Rubber - Determination of Thermal Conductivity - Hot Wire Method", "GB / T528-2009 Rubber, Vulcanized or Thermoplastic Rubber - Determination of Stress, Strain and Deformation Energy", "GB / T531.1-2008 Rubber, Vulcanized or Thermoplastic Rubber - Determination of Indentation Hardness - Part 1: Shore Durometer Method (Shore Hardness)", and "GB / T 7759.1-2015 Rubber, Vulcanized or Thermoplastic Rubber - Determination of Compression Set - Part 1: At Normal and Elevated Temperatures", the above-prepared rubber was sampled and tested, and the test results are as follows:

[0118]

[0119] *The smaller the compression permanent deformation, the better the material's resilience and deformation resistance.

[0120] The above experimental results show that the product of Example 1 has the following advantages over the products of Comparative Examples 1-3: high thermal conductivity and low compression set. Furthermore, the tensile strength of the product of Example 1 reaches over 20 MPa, meeting the tensile strength requirements for rubber tracks and satisfying industrial needs.

[0121] Although the specific embodiments of the present invention have been described in detail, those skilled in the art will understand that various modifications and changes can be made to the details based on all the teachings disclosed, and these changes are all within the scope of protection of the present invention. The full scope of the present invention is given by the appended claims and any equivalents thereof.

Claims

1. A method for preparing a rubber material, comprising the steps of mixing a raw material composition; wherein: In parts by weight, the raw material composition comprises: 100 parts of rubber raw materials; 1~5 parts of vulcanizing agent; 1-5 parts paraffin wax; 1-5 parts of stearic acid; 20-30 parts of first pretreated carbon fibers; 25-35 parts of hexagonal boron nitride powder that has undergone a second pretreatment; 25-35 parts of nano copper powder that has undergone the third pretreatment; wherein the average length of the carbon fibers is 3 mm to 10 mm; Wherein, the average particle size of the hexagonal boron nitride powder is 10 μm to 200 μm; Wherein, the average particle size of the nano copper powder is 5nm~100nm; Wherein, the first pretreatment comprises treating the carbon fiber with a silane coupling agent first, and then etching with CO2 plasma; Wherein, the second pretreatment comprises treating the hexagonal boron nitride powder with a silane coupling agent; Wherein, the third pretreatment comprises treating the nano copper powder with a solution containing octadecylamine and stearic acid; The rubber raw material contains natural rubber and butadiene rubber, and the weight ratio of natural rubber to butadiene rubber is 80-95:5-10; The rubber material has the following properties: -Thermal conductivity is 3~3.5 W / m·K; -Tensile strength is 20~22MPa; -Hardness 70~80HA; -Compression set at room temperature is 6~7%.

2. The method for preparing a rubber material according to claim 1, wherein: The rubber raw material contains natural rubber and butadiene rubber, and the weight ratio of the natural rubber to the butadiene rubber is 90-95:5-10.

3. The method for preparing a rubber material according to claim 1, wherein the silane coupling agent is KH-550 silane coupling agent.

4. The method for preparing a rubber material according to claim 1, wherein: The average particle size of the nano copper powder is 40-60 nm.

5. The method for preparing a rubber material according to claim 1, wherein: The solution containing octadecylamine and stearic acid is a chloroform solution containing octadecylamine and stearic acid.

6. The method for preparing a rubber material according to claim 1, wherein in the raw material composition, the weight portion of the vulcanizing agent is 1-2 parts, the weight portion of the paraffin wax is 1-2 parts, and the weight portion of the stearic acid is 1-2 parts.

7. The method for preparing a rubber material according to claim 1, wherein the raw material composition further comprises: 2~5 parts of antioxidant; 1~5 parts of accelerator.

8. The method for preparing a rubber material according to claim 7, wherein: The accelerator is selected from one or more of thiuram accelerators and sulfenamide accelerators.

9. The method for preparing a rubber material according to claim 1, wherein the raw material composition further comprises: 1-10 parts zinc oxide powder; Carbon black powder 0-60 parts; Wherein, the average particle size of the zinc oxide powder is 0.5 to 1.5 microns; The apparent density of the carbon black powder is 0.3-0.4 g / cm 3 .

10. The method for preparing a rubber material according to claim 1, wherein the raw material composition comprises: Natural rubber 90~95 parts 5~10 parts of butadiene rubber 1.5-2 parts sulfur 1~1.2 parts paraffin wax 1~2 parts of stearic acid Antioxidant 4040 1~2 parts Antioxidant D 1~2 parts Accelerator CZ 0.5~1 part Accelerator TMTD 0.8~1.2 parts 3~5 parts zinc oxide powder 40~50 parts of carbon black powder Carbon fiber 23~27 parts 28~32 parts hexagonal boron nitride powder 28~32 parts of nano copper powder.

11. The method for preparing a rubber material according to claim 1, wherein the raw material composition comprises: 95 parts of natural rubber 5 parts of butadiene rubber 1.8 parts sulfur 1 part paraffin 1.5 parts of stearic acid 1.5 parts of antioxidant 4040 1.5 parts of antioxidant D Accelerator CZ 0.8 parts 1 part of TMTD accelerator 4 parts zinc oxide powder 45 parts carbon black powder 25 parts carbon fiber 30 parts hexagonal boron nitride powder 30 parts of nano copper powder.

12. The method for preparing the rubber material according to claim 1, comprising: The rubber raw materials are plasticized by rollers using a rubber mixer, and then other components of the raw material composition except the vulcanizing agent are added and mixed. After mixing, vulcanization treatment is performed.

13. The method for preparing a rubber material according to claim 11, wherein the roller temperature of the rubber mixer is controlled to be 45-55°C during the mixing process.

14. A rubber material prepared by the method according to any one of claims 1 to 13.

15. A rubber crawler made of the rubber material according to claim 14.

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