High thermal conductivity and low heat generation rubber and preparation method thereof, and tire

Abstract

The present application relates to the field of rubber materials, and specifically discloses a high thermal conductivity and low heat generation rubber, a preparation method thereof, and a tire. The high thermal conductivity and low heat generation rubber comprises the following raw materials in parts by weight: 100 parts of natural rubber; 38-51 parts of reinforcing material; 1-3 parts of stearic acid; 1.5-2.5 parts of antioxidant; 1-2 parts of silane coupling agent; 0.5-2 parts of carbon nanotube dispersion material; 1-2 parts of tackifying resin; 1.5-3.0 parts of insoluble sulfur; 0.5-1.2 parts of accelerator; 0.5-1.0 parts of vulcanizing agent; 0.1-0.5 parts of anti-vulcanization reversion agent; 0.1-0.3 parts of anti-scorch agent. The preparation method of the high thermal conductivity and low heat generation rubber comprises a first masterbatch mixing step, a second masterbatch mixing step, and a final mixing step. A tire is made using the above-mentioned high thermal conductivity and low heat generation rubber. The obtained rubber has good thermal conductivity, low compression heat generation, and high tensile strength; the prepared tire has the advantages of high thermal conductivity and low heat generation.

Description

Technical Field

[0001] The present application relates to the field of rubber materials, and more specifically, to a high thermal conductivity and low heat generation rubber and a preparation method thereof, and a tire. Background Art

[0002] The 63-inch all-steel giant construction machinery radial tire has a tire diameter of up to 4.03m, a mass of up to 5.8t, and a section width of up to 1496mm. It is currently the world's largest all-steel giant construction machinery radial tire. The shoulder thickness of the 63-inch tire can be up to 220mm. The shoulder pad rubber is used in the thickest position of the tire to connect the carcass, tread rubber and belt layer rubber.

[0003] 63-inch all-steel giant engineering machinery radial tires are generally used in high-load and heavy-load environments, and the shoulder pad rubber used in the tires is mainly made of natural rubber, which is a poor conductor of heat. Due to the heavy load capacity of radial tires, the shoulder pad rubber used in the tires is generally thicker. They are also used under special environmental conditions. The cyclic load of the tire generates a lot of heat. The shoulder pad rubber is subject to a high frequency of compression strain in the shoulder area of ​​the tire, and the internal temperature is extremely easy to rise but cannot be discharged in time, resulting in heat accumulation, which accelerates rubber aging and reduces rubber tensile properties, and then causes shoulder hollows in the thicker shoulder pad rubber parts of the tire, causing early tire damage and shortening the tire service life. Summary of the invention

[0004] The present application provides a high thermal conductivity and low heat generation rubber and a preparation method thereof, and a tire. The obtained rubber has good thermal conductivity, low compression heat generation, and high tensile strength. The prepared tire can be used for a long time under complex working conditions, has the advantages of high thermal conductivity and low heat generation, and can effectively extend the service life of the tire.

[0005] In a first aspect, the present application provides a high thermal conductivity and low heat generation rubber, which adopts the following technical solution:

[0006] A high thermal conductivity and low heat generation rubber comprises the following raw materials in parts by weight: 100 parts of natural rubber; 38-51 parts of reinforcing material; 1-3 parts of stearic acid; 1.5-2.5 parts of antioxidant; 1-2 parts of silane coupling agent; 0.5-2 parts of carbon nanotube dispersion material; 1-2 parts of tackifying resin; 1.5-3.0 parts of insoluble sulfur; 0.5-1.2 parts of accelerator; 0.5-1.0 parts of vulcanizing agent; 0.1-0.5 parts of anti-reversion agent; 0.1-0.3 parts of anti-scorch agent; the carbon nanotube dispersion material comprises 6-10wt% of single-walled carbon nanotubes and 8-10wt% of oxidized starch, 10-20wt% of gelatin solution containing coupling agent and the balance of liquid butadiene rubber.

[0007] Furthermore, the natural rubber is selected from 3# smoked sheet rubber, with a tensile strength of 25MPa-30MPa and an elongation of 450%-500%, to ensure the comprehensive physical properties of the rubber material.

[0008] Furthermore, the anti-reversion agent is 1,3-bis(citricarboxylic imide methyl)benzene, and the accelerator is N-tert-butyl-2-benzothiazole sulfonamide.

[0009] Furthermore, the antioxidant is selected from 2,2,4-trimethyl-1,2-dihydroquinoline polymer and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; the mass ratio thereof is 1:(0.5-3), and the further preferred mass ratio is 1:3.

[0010] Furthermore, the vulcanizing agent is 1,1′-dithiobiscaprolactam; the scorch retarder is N-cyclohexylthiophthalimide. The vulcanizing agent has the characteristics of heat resistance, fatigue resistance and anti-reduction. The scorch retarder mainly prevents the rubber from scorching during the rubber vulcanization process and ensures the performance of the vulcanized rubber.

[0011] Single-walled carbon nanotubes, oxidized starch, gelatin solution containing a coupling agent and liquid butadiene rubber are used as carbon nanotube dispersions, and liquid butadiene rubber is used as a matrix. Under certain conditions, the gelatin solution containing a coupling agent can cross-link with the oxidized starch, so that the carbon nanotube dispersion forms a tight carbon nanotube network thermal conductive structure inside, which can well transfer the heat accumulated inside the rubber, significantly improve the thermal conductivity of the rubber material, and reduce the compression heat generated by the rubber material under complex working conditions.

[0012] The gelatin solution containing coupling agent can not only effectively promote the effective combination between the components, but also improve the dispersion performance of carbon nanotube dispersion in the rubber system, and further cooperate with the tackifying resin to improve the stability of the system crosslinking density and further improve the tensile strength of the rubber material.

[0013] 1,3-bis(citricarboxylic imide methyl)benzene is selected as an anti-reversion agent, and N-tert-butyl-2-benzothiazolesulfonamide is selected as an accelerator. The heat-stable carbon-carbon cross-linking bonds compensate for the sulfur cross-linking bonds destroyed by reversion, thereby maintaining the stability of the cross-linking density inside the rubber, so that the vulcanized rubber can maintain good performance. In combination with insoluble sulfur, accelerators and reinforcing materials, it can effectively improve the tensile strength of rubber materials, assist in improving the heat aging resistance of rubber materials, and extend the service life of rubber.

[0014] Preferably, the coupling agent-containing gelatin solution comprises 10-20 wt % of the amino coupling agent and 80-90 wt % of the gelatin aqueous solution.

[0015] Preferably, the carbon nanotube dispersion is prepared by the following steps: uniformly mixing single-walled carbon nanotubes and oxidized starch to obtain a mixture, heating liquid butadiene rubber and stirring, and simultaneously adding the mixture and a gelatin solution containing a coupling agent to the heated liquid butadiene rubber to obtain a carbon nanotube dispersion in a paste form.

[0016] Furthermore, the oxidation degree of the oxidized starch is 40-60%, and the mass concentration of the gelatin aqueous solution is 15-22%.

[0017] By adopting the above technical scheme, the amino coupling agent can not only play a good activation role and promote the formation of the carbon nanotube network thermal conductive structure, but also play an excellent dispersing role, so that the carbon nanotube dispersion can evenly fill the entire rubber system, play a good thermal conductive effect, and assist in improving the mechanical properties of the rubber material.

[0018] Preheating the liquid butadiene rubber can further promote the formation of the nanotube network thermal conductive structure, thereby forming a tight thermal conductive network structure in the system, effectively improving the thermal conductivity of the rubber material, reducing compression heat generation, and thus extending the service life of the rubber.

[0019] Preferably, the single-walled carbon nanotubes have an average diameter of 1.5-2 nm, an average length of 4-8 μm, and a specific surface area of ​​155-180 m 2 / g.

[0020] By adopting the above technical solution and selecting single-walled carbon nanotubes with specific specifications and parameters, not only can they play an excellent thermal conductive role, but they can also play a good reinforcing role, effectively improving the thermal conductivity and mechanical properties of rubber.

[0021] Preferably, the reinforcing material includes at least two of zinc oxide, carbon black and white carbon black.

[0022] Preferably, the reinforcing material comprises the following components in parts by weight: 30-35 parts of carbon black, 5-10 parts of white carbon black, and 3-6 parts of zinc oxide.

[0023] Furthermore, the carbon black is selected from coarse particle size carbon black N660, and the white carbon black is precipitated white carbon black with a specific surface area of ​​165m 2 / g,

[0024] By adopting the above technical scheme, since carbon black N660 and white carbon black are compounded, the heat generation of the vulcanized rubber can be reduced, the elasticity and tensile strength of the rubber can be improved, zinc oxide can be used as a vulcanization activator to promote the increase of the crosslinking density of the rubber, and the selection of carbon black, white carbon black and zinc oxide for combination can assist in improving the heat aging resistance of the rubber, reduce heat generation, improve elasticity and extend the service life of the rubber.

[0025] Preferably, the tackifying resin is a condensate of butylphenol and acetylene.

[0026] By adopting the above technical scheme, the tackifying resin contains phenolic hydroxyl groups, and the gelatin solution containing the coupling agent contains amino groups, which can further combine and enhance the intermolecular forces during the rubber refining process, further promote the carbon nanotube dispersion to form a tight thermal conductive network structure in the system, improve the thermal conductivity of the rubber and improve its tensile strength.

[0027] Preferably, the silane coupling agent is bis-[y-(triethoxysilyl)propyl]tetrasulfide.

[0028] By adopting the above technical solution, the silane coupling agent can activate and disperse the reinforcing material, significantly improve the dispersibility of the reinforcing material components in the system, promote its effectiveness, and enable better combination between the components.

[0029] In a second aspect, the present application provides a method for preparing a high thermal conductivity and low heat generation rubber, using the following technical solution: A method for preparing a high thermal conductivity and low heat generation rubber, comprising the following steps:

[0030] The first stage masterbatch mixing step includes: plasticizing the natural rubber, adding a reinforcing material, stearic acid, a tackifying resin and an antioxidant, mixing, and then adding a silane coupling agent to mix to obtain a rubber compound, and then refining and cooling the rubber compound to obtain a first stage masterbatch;

[0031] The second-stage masterbatch mixing step is as follows: mixing the first-stage masterbatch and the carbon nanotube dispersion, and then refining and cooling to obtain the second-stage masterbatch; the final refining step is as follows: refining the second-stage masterbatch with insoluble sulfur, accelerator, vulcanizing agent, anti-scorch agent and anti-vulcanization reversion agent, and then refining and cooling to obtain rubber.

[0032] Further, in a masterbatch mixing step, natural rubber is plasticized to obtain plasticized rubber, and plasticized rubber, reinforcing material, stearic acid, tackifying resin and antioxidant are added to an internal mixer according to a filling factor of 70-75% for mixing, and the temperature of the rubber is controlled at 110-140° C. by pressing the top plug; the mixing time is 30-60 seconds; a silane coupling agent is added, and the temperature of the rubber is controlled at 120-160° C. by pressing the top plug, and the mixing time is 2-4 minutes; the rubber is discharged to the lower sheet of the screw extruder to control the thickness of the rubber sheet to 5-7 mm, and it is transported to an open mixer, the rubber material is re-mixed and cooled, and the curled rubber material is parked for 6-8 hours to obtain a masterbatch;

[0033] Furthermore, in the second-stage masterbatch mixing step, the first-stage masterbatch and the carbon nanotube dispersion are added to the internal mixer according to the filling factor of 70-75%, the rubber temperature is controlled at 120-140° C. by pressing the top plug, the mixing time is 2-3 minutes, the film thickness of the screw extruder is controlled to be 5-7 mm, and the film is transported to the open mixer, the rubber is turned over and cooled, and the curled rubber is parked for 6-8 hours to obtain the second-stage masterbatch;

[0034] Furthermore, in the final mixing step, the internal mixer maintained a low rotor speed of 30 rpm and an upper push bolt pressure of 30 N / cm 2 ; Add the second-stage masterbatch into the internal mixer, add insoluble sulfur, accelerator, anti-scorch agent, anti-vulcanization reversion agent, and add them into the internal mixer according to the filling factor of 70-75% for mixing; control the rubber temperature at 100-110°C, and the rubber mixing time is 2-3min; discharge the rubber to the open mixer, re-mix the cooled rubber, and re-mix the cooled rubber to obtain the rubber product.

[0035] By adopting the above preparation method and combining specific components, the obtained rubber has good thermal conductivity, low compression heat generation, and high tensile strength.

[0036] In a third aspect, the present application provides a tire, which adopts the following technical solution:

[0037] A tire is made of the above-mentioned high thermal conductivity and low heat generation rubber.

[0038] By adopting the above technical solution, the prepared tire can be used for a long time under complex working conditions, has the advantages of high thermal conductivity and low heat generation, and the service life of the tire is long.

[0039] In summary, this application has the following beneficial effects:

[0040] 1. Single-walled carbon nanotubes, oxidized starch, gelatin solution containing coupling agent and liquid butadiene rubber are used as carbon nanotube dispersions, and liquid butadiene rubber is used as a matrix. Under certain conditions, the gelatin solution containing coupling agent can cross-link with the oxidized starch, so that the carbon nanotube dispersion forms a compact carbon nanotube network thermal conductive structure inside, which can transfer the heat accumulated inside the rubber well, significantly improve the thermal conductivity of the rubber material, and reduce the compression heat generation of the rubber material under complex working conditions.

[0041] 2. 1,3-bis(citricarboxylic imide methyl)benzene is selected as the anti-reversion agent, and N-tert-butyl-2-benzothiazolesulfonamide is selected as the accelerator. The heat-stable carbon-carbon cross-linking bonds compensate for the sulfur cross-linking bonds destroyed by reversion, thereby maintaining the stability of the cross-linking density inside the rubber, so that the vulcanized rubber can maintain good performance. In combination with insoluble sulfur, accelerators and reinforcing materials, it can effectively improve the tensile strength of rubber materials, assist in improving the heat aging resistance of rubber materials, and extend the service life of rubber.

[0042] 3. The tackifying resin contains phenolic hydroxyl groups, and the gelatin solution containing coupling agents contains amino groups, which can further combine and enhance the intermolecular forces during the rubber refining process, further promote the carbon nanotube dispersion to form a tight thermal conductive network structure in the system, improve the thermal conductivity of the rubber, and increase its tensile strength. DETAILED DESCRIPTION

[0043] The present invention is further described in detail below in conjunction with the examples. Unless otherwise specified, the raw materials are all common commercially available raw materials.

[0044] In the current research, in order to improve the thermal conductivity of rubber and extend the service life of tires, researchers have tried to use high thermal conductivity materials such as carbon nanotubes to prepare high thermal conductivity rubber composite materials. However, during the research process, the inventors found that if high thermal conductivity materials such as carbon nanotubes are directly added, due to the particularity of their structure (carbon nanotubes are mainly composed of several to dozens of layers of coaxial circular tubes composed of hexagonally arranged carbon atoms, with a fixed distance of about 0.34nm between layers, and a diameter of generally 2-20nm), it is difficult to disperse in the rubber system and combine with rubber and other raw materials to exert the thermal conductivity of the material. Instead, it is easy to form agglomerates that affect the mechanical properties of the vulcanized rubber. In the course of further research, the inventors found that even if the single-walled carbon nanotubes are first surface-modified, for example, they are pre-treated with a surfactant such as a silane coupling agent, although the dispersibility of the single-walled carbon nanotubes can be improved to a certain extent, the resulting rubber material still has uneven thermal conductivity and high compression heat generation. Further research found that by selecting specific single-walled carbon nanotubes and combining them with oxidized starch, a gelatin solution containing a coupling agent, and liquid butadiene rubber, a pre-dispersed modified product can be made under certain conditions. During the rubber refining process, it only needs to be added during the mixing of the second-stage masterbatch. The single-walled carbon nanotube dispersion can be evenly distributed in the rubber system using a general mixing process and play an excellent thermal conductive role, forming a carbon nanotube network thermal conductive structure, which can further ensure the cross-linking density of the rubber system and improve the tensile properties of the rubber.

[0045] Preparation example of carbon nanotube dispersion

[0046] Preparation Example 1

[0047] The carbon nanotube dispersion is prepared by the following steps: uniformly mixing single-walled carbon nanotubes and oxidized starch to obtain a mixture, heating liquid butadiene rubber to 40° C. and stirring, adding the mixture and a gelatin solution containing a coupling agent to the heated liquid butadiene rubber, and mixing to obtain a carbon nanotube dispersion in a paste form;

[0048] The single-walled carbon nanotubes are 6 parts, oxidized starch is 8 parts, gelatin solution containing coupling agent is 10 parts, and liquid butadiene rubber is 76 parts; the oxidation degree of oxidized starch is 40%, the average diameter of the single-walled carbon nanotubes is 1.5-1.8nm, the average length is 4-6μm, and the specific surface area is 155-170m 2 / g;

[0049] The gelatin solution containing coupling agent comprises 20 wt% of amino coupling agent and 80 wt% of gelatin aqueous solution; the mass concentration of the gelatin aqueous solution is 22%.

[0050] Preparation Example 2

[0051] The carbon nanotube dispersion is prepared by the following steps: uniformly mixing single-walled carbon nanotubes and oxidized starch to obtain a mixture, heating liquid butadiene rubber to 45° C. and stirring, adding the mixture and a gelatin solution containing a coupling agent to the heated liquid butadiene rubber, and mixing to obtain a carbon nanotube dispersion in a paste form;

[0052] The single-walled carbon nanotubes are 10 parts, oxidized starch is 10 parts, gelatin solution containing coupling agent is 20 parts, and liquid butadiene rubber is 60 parts; the oxidation degree of oxidized starch is 50%, the average tube diameter of the single-walled carbon nanotubes is 1.5-1.8nm, the average length is 4-6μm, and the specific surface area is 155-170m 2 / g;

[0053] The gelatin solution containing the coupling agent comprises 10 wt% of the amino coupling agent and 90 wt% of the gelatin aqueous solution, and the mass concentration of the gelatin aqueous solution is 15%.

[0054] Preparation Example 3

[0055] The carbon nanotube dispersion is prepared by the following steps: uniformly mixing single-walled carbon nanotubes and oxidized starch to obtain a mixture, heating liquid butadiene rubber to 40° C. and stirring, adding the mixture and a gelatin solution containing a coupling agent to the heated liquid butadiene rubber, and mixing to obtain a carbon nanotube dispersion in a paste form;

[0056] The single-walled carbon nanotubes are 8 parts, oxidized starch is 8 parts, gelatin solution containing coupling agent is 16 parts, and liquid butadiene rubber is 68 parts; the oxidation degree of oxidized starch is 60%, the average diameter of the single-walled carbon nanotubes is 1.8-2nm, the average length is 6-8μm, and the specific surface area is 170-180m 2 / g;

[0057] The gelatin solution containing the coupling agent comprises 16 wt % of the amino coupling agent and 84 wt % of the gelatin aqueous solution, and the mass concentration of the gelatin aqueous solution is 20 %.

[0058] Preparation Example 4

[0059] The difference from Preparation Example 3 is that the average diameter of the single-walled carbon nanotubes is 1.8-1.9 nm, the average length is 5-6 μm, and the specific surface area is 160 m 2 / g; the rest are the same as in Preparation Example 3.

[0060] Comparative Preparation Example 1

[0061] The carbon nanotube dispersion is prepared by the following steps: 8 parts of single-walled carbon nanotubes are mixed with 90 parts of liquid butadiene rubber and 2 parts of silane coupling agent.

[0062] Comparative Preparation Example 2

[0063] The carbon nanotube dispersion is prepared by the following steps: 88 parts of liquid butadiene rubber are heated to 40° C. and stirred, and then 8 parts of single-walled carbon nanotubes and 4 parts of oxidized starch are added and mixed evenly.

[0064] Comparative Preparation Example 3

[0065] The carbon nanotube dispersion is prepared by the following steps: 88 parts of liquid butadiene rubber are heated to 40°C and stirred, and then 8 parts of single-walled carbon nanotubes and 4 parts of gelatin aqueous solution are added and mixed evenly, wherein the mass concentration of the gelatin aqueous solution is 20%.

[0066] Example

[0067] Example 1

[0068] A high thermal conductivity and low heat generation rubber, comprising the following raw materials: 100 parts of natural rubber; 38 parts of reinforcing material; 3 parts of stearic acid; 1.5 parts of antioxidant; 1 part of silane coupling agent; 0.5 parts of carbon nanotube dispersion obtained in Preparation Example 1; 1 part of tackifying resin; 1.5 parts of insoluble sulfur; 0.5 parts of accelerator; 0.5 parts of vulcanizing agent; 0.1 parts of anti-reversion agent; 0.1 parts of anti-scorch agent;

[0069] The antioxidants are 2,2,4-trimethyl-1,2-dihydroquinoline polymer and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; the mass ratio is 1:0.5; the reinforcing material includes 30 parts of carbon black N660 and 8 parts of zinc oxide.

[0070] The high thermal conductivity and low heat generation rubber comprises the following preparation steps:

[0071] The first-stage masterbatch mixing step comprises: plasticizing natural rubber to obtain plasticized rubber, adding plasticized rubber, reinforcing material, stearic acid, tackifying resin and antioxidant into an internal mixer according to a filling factor of 70-75% and mixing, and controlling the temperature of the rubber at 140° C. by pressing a top plug; mixing for 60 seconds; adding a silane coupling agent, controlling the temperature of the rubber at 120° C. by pressing a top plug, and mixing for 2 minutes; discharging the rubber to the lower sheet of the screw extruder to control the thickness of the rubber sheet to 5-7 mm, conveying the rubber sheet to an open mixer, refining and cooling the rubber material, and leaving the curled rubber material for 6 hours to obtain a first-stage masterbatch;

[0072] The second-stage masterbatch mixing step: the first-stage masterbatch and the carbon nanotube dispersion are added into an internal mixer according to a filling factor of 70-75%, the rubber temperature is controlled at 120°C by pressing the top plug, the mixing time is 2-3min, the film thickness of the film is controlled at 5-7mm by the screw extruder, and the film is transported to an open mixer, the rubber material is turned over and cooled, and the curled rubber material is parked for 8h to obtain the second-stage masterbatch;

[0073] Final mixing step: The internal mixer keeps the rotor at a low speed of 30 rpm and the upper bolt pressure at 30 N / cm 2; Add the second-stage masterbatch into the internal mixer, add insoluble sulfur, accelerator, anti-scorch agent, anti-vulcanization reversion agent, and add them into the internal mixer according to the filling factor of 70-75% for mixing; control the rubber temperature at 100°C, and the mixing time is 2-3min; discharge the rubber to the open mixer, and remix the cooled rubber to obtain the rubber product.

[0074] Example 2

[0075] A high thermal conductivity and low heat generation rubber, comprising the following raw materials: 100 parts of natural rubber; 45 parts of reinforcing material; 1 part of stearic acid; 2 parts of antioxidant; 2 parts of silane coupling agent; 1.2 parts of carbon nanotube dispersion obtained in Preparation Example 1; 1 part of tackifying resin; 2 parts of insoluble sulfur; 1 part of accelerator; 0.8 parts of vulcanizing agent; 0.2 parts of anti-reversion agent; 0.3 parts of anti-scorch agent;

[0076] The antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; the mass ratio is 1:1.5; the reinforcing material includes 35 parts of carbon black N660 and 10 parts of white carbon black;

[0077] The preparation method of the high thermal conductivity and low heat generation rubber is the same as that in Example 1.

[0078] Example 3

[0079] A high thermal conductivity and low heat generation rubber, comprising the following raw materials: 100 parts of natural rubber; 44 parts of reinforcing material; 1 part of stearic acid; 2.5 parts of antioxidant; 1 part of silane coupling agent; 1 part of carbon nanotube dispersion obtained in Preparation Example 1; 2 parts of tackifying resin; 3 parts of insoluble sulfur; 1.2 parts of accelerator; 0.8 parts of vulcanizing agent; 0.5 parts of anti-reversion agent; 0.2 parts of anti-scorch agent;

[0080] The antioxidant is 2,2,4-trimethyl-1,2-dihydroquinoline polymer and N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine; the mass ratio is 1:3; the reinforcing material includes 30 parts of carbon black, 8 parts of white carbon black and 6 parts of zinc oxide;

[0081] The preparation method of the high thermal conductivity and low heat generation rubber is the same as that in Example 1.

[0082] Example 4

[0083] The difference from Example 3 is that the carbon nanotube dispersion obtained in Preparation Example 2 is selected, and the rest is the same as Example 3.

[0084] Example 5

[0085] The difference from Example 3 is that the carbon nanotube dispersion obtained in Preparation Example 3 is selected, and the rest is the same as Example 3.

[0086] Example 6

[0087] The difference from Example 3 is that the carbon nanotube dispersion obtained in Preparation Example 4 is selected, and the rest is the same as Example 3.

[0088] Example 7

[0089] The difference from Example 6 is that the reinforcing material includes 40 parts of carbon black, 5 parts of white carbon black and 5 parts of zinc oxide, and the rest is the same as Example 6.

[0090] Example 8

[0091] The difference from Example 6 is that the silane coupling agent is silane coupling agent KH550, and the rest is the same as Example 6.

[0092] Example 9

[0093] The difference from Example 7 is that the high thermal conductivity and low heat generation rubber comprises the following preparation steps:

[0094] The first-stage masterbatch mixing step comprises: plasticizing natural rubber to obtain plasticized rubber, adding plasticized rubber, reinforcing material, stearic acid, tackifying resin and antioxidant into an internal mixer according to a filling factor of 70-75% and mixing, and controlling the temperature of the rubber at 120° C. by pressing a top plug; mixing for 60 seconds; adding a silane coupling agent, controlling the temperature of the rubber at 143° C. by pressing a top plug, and mixing for 2 minutes; discharging the rubber to the lower sheet of the screw extruder to control the thickness of the rubber sheet to 5-7 mm, conveying the rubber sheet to an open mixer, refining and cooling the rubber material, and leaving the curled rubber material for 8 hours to obtain a first-stage masterbatch;

[0095] The second-stage masterbatch mixing step: the first-stage masterbatch and the carbon nanotube dispersion are added into an internal mixer according to a filling factor of 70-75%, the rubber temperature is controlled at 135° C. by pressing the top plug, the mixing time is 2-3 minutes, the film thickness of the film is controlled at 5-7 mm by the screw extruder, and the film is transported to an open mixer, the rubber material is turned over and cooled, and the curled rubber material is parked for 8 hours to obtain the second-stage masterbatch;

[0096] Final mixing step: The internal mixer keeps the rotor at a low speed of 30 rpm and the upper bolt pressure at 30 N / cm 2 ; Add the second-stage masterbatch into the internal mixer, add insoluble sulfur, accelerator, anti-scorch agent, anti-vulcanization reversion agent, and add them into the internal mixer according to the filling factor of 70-75% for mixing; control the rubber temperature at 110°C, and the mixing time is 2-3min; discharge the rubber to the open mixer, and mix the cooled rubber to obtain the rubber product.

[0097] Comparative Example

[0098] Comparative Example 1

[0099] The difference from Example 9 is that the carbon nanotube dispersion prepared in Comparative Preparation Example 1 is selected, and the rest is the same as Example 9.

[0100] Comparative Example 2

[0101] The difference from Example 9 is that the carbon nanotube dispersion prepared in Comparative Preparation Example 2 is selected, and the rest is the same as Example 9.

[0102] Comparative Example 3

[0103] The difference from Example 9 is that the carbon nanotube dispersion prepared in Comparative Preparation Example 3 is selected, and the rest is the same as Example 9.

[0104] Comparative Example 4

[0105] The difference from Example 9 is that single-walled carbon nanotubes are used to replace the carbon nanotube dispersion material, and the rest is the same as Example 9.

[0106] Comparative Example 5

[0107] The difference from Example 9 is that the reinforcing material is 40 parts of carbon black N375, and the rest is the same as Example 9.

[0108] Comparative Example 6

[0109] The difference from Example 9 is that aliphatic hydrocarbon C5 resin is used to replace the tackifying resin, and the rest is the same as Example 9.

[0110] Performance testing

[0111] The tensile strength of the samples prepared in Examples 1-9 and Comparative Examples 1-6 was measured according to GB / T 528-2009, and the compression heat generation was measured according to GB / T1687.3-2016. The results are recorded in Table 1.

[0112] Thermal conductivity is measured according to GB / T 10294-2008. Rubber thermal conductivity performance test: tested on JTKD-II fast thermal conductivity tester. Test principle: The test method is transient method, which uses the physical characteristics of non-steady-state heat transfer of the sample. The temperature change rate of the sample surface is collected at high speed through the test film with heating and high-precision temperature sensor. The higher the value, the better the thermal conductivity.

[0113] The tire durability test was carried out according to GB / T 30193-2013. Due to the high cost of tire production, the rubber materials obtained in Example 9 and Comparative Examples 1-4 were used to make tires and the tire durability test was carried out: duration 24 h, tire load: 82500 KN, test drum speed: 15 km / h, and the temperature of the tire shoulder was measured during the durability test. The results are recorded in Table 2.

[0114] Table 1

[0115]

[0116]

[0117] Table 2

[0118] Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Durability test tire shoulder temperature measurement / ℃ 57 82 92 96 90

[0119] It can be seen from Examples 1-9 in combination with Table 1 that the rubber obtained by the present application has good thermal conductivity, low compression heat generation, and high tensile strength; the prepared tire can be used for a long time under complex working conditions, has the advantages of high thermal conductivity and low heat generation, and has a long tire life.

[0120] Combining Example 9 and Comparative Examples 1-4 and Table 1-2, it can be seen that in the preparation process of the carbon nanotube dispersion, the lack of corresponding components such as oxidized starch, aqueous solution containing gelatin or replacement of the components cannot effectively improve the thermal conductivity of the rubber material and reduce the compression heat generation. This is because single-walled carbon nanotubes, oxidized starch, gelatin solution containing a coupling agent and liquid butadiene rubber are used as carbon nanotube dispersions, and liquid butadiene rubber is used as a matrix. Under certain conditions, the gelatin solution containing a coupling agent can cross-link with the oxidized starch, so that the carbon nanotube dispersion forms a tight carbon nanotube network thermal conductive structure inside, which can transfer the heat accumulated inside the rubber well, thereby significantly improving the thermal conductivity of the rubber material, reducing compression heat generation, and at the same time improving the tensile strength of the rubber material, significantly improving the heat aging resistance of the rubber material, and extending the service life of the rubber.

[0121] Combining Example 9 and Comparative Example 5 with Table 1-2, it can be seen that when only carbon black N375 is used as a reinforcing material, the heat generation of the vulcanized rubber increases, the elasticity and tensile strength of the rubber decrease, and the crosslinking density of the rubber decreases, thereby affecting the comprehensive performance of the rubber material.

[0122] Combining Example 9 and Comparative Example 6 and Table 1-2, it can be seen that after the aliphatic hydrocarbon C5 resin replaces the tackifying resin, the comprehensive performance of the rubber material also decreases. This is because the tackifying resin of the present application is a condensation product of butylphenol and acetylene, containing phenolic hydroxyl groups, and the gelatin solution containing the coupling agent contains amino groups, which can be combined to enhance the intermolecular force during the rubber refining process, further promote the carbon nanotube dispersion to form a tight thermal conductive network structure in the system, improve the thermal conductivity of the rubber, and improve its tensile strength and heat aging resistance.

[0123] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A high thermal conductivity and low heat generation rubber, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of natural rubber; 38-51 parts of reinforcing material; 1-3 parts of stearic acid; 1.5-2.5 parts of antioxidant; 1-2 parts of silane coupling agent; 0.5-2 parts of carbon nanotube dispersion material; 1-2 parts of tackifying resin; 1.5-3.0 parts of insoluble sulfur; 0.5-1.2 parts of accelerator; 0.5-1.0 parts of vulcanizing agent; 0.1-0.5 parts of anti-reversion agent; 0.1-0.3 parts of anti-scorch agent; the tackifying resin is a condensate of butylphenol and acetylene; the anti-reversion agent is 1,3-bis(citricarboxylic imide methyl)benzene, and the accelerator is N-tert-butyl-2-benzothiazole sulfenamide; The carbon nanotube dispersion comprises 6-10wt% of single-walled carbon nanotubes, 8-10wt% of oxidized starch, 10-20wt% of a gelatin solution containing a coupling agent, and the remainder of liquid butadiene rubber; the gelatin solution containing a coupling agent comprises 10-20wt% of an amino coupling agent and 80-90wt% of a gelatin aqueous solution; The carbon nanotube dispersion is prepared by the following steps: uniformly mixing single-walled carbon nanotubes and oxidized starch to obtain a mixture, heating liquid butadiene rubber and stirring, adding the mixture and a gelatin solution containing a coupling agent to the heated liquid butadiene rubber at the same time, and mixing to obtain a carbon nanotube dispersion in a paste form.

2. The high thermal conductivity and low heat generation rubber according to claim 1, characterized in that: The single-walled carbon nanotubes have an average diameter of 1.5-2 nm, an average length of 4-8 μm, and a specific surface area of ​​155-180 m 2 / g.

3. The high thermal conductivity and low heat generation rubber according to claim 1, characterized in that: The reinforcing material includes at least two of zinc oxide, carbon black and white carbon black.

4. The high thermal conductivity and low heat generation rubber according to claim 3, characterized in that: The reinforcing material comprises the following components in parts by weight: 30-35 parts of carbon black, 5-10 parts of white carbon black, and 3-6 parts of zinc oxide.

5. The high thermal conductivity and low heat generation rubber according to claim 1, characterized in that: The silane coupling agent is bis-[y-(triethoxysilyl)propyl]tetrasulfide.

6. A method for preparing the high thermal conductivity and low heat generation rubber according to any one of claims 1 to 5, characterized in that: The steps include: The first stage masterbatch mixing step includes: plasticizing the natural rubber, adding a reinforcing material, stearic acid, a tackifying resin and an antioxidant, mixing, and then adding a silane coupling agent to mix to obtain a rubber compound, and then refining and cooling the rubber compound to obtain a first stage masterbatch; The second-stage masterbatch mixing step: mixing the first-stage masterbatch and the carbon nanotube dispersion material, and then mixing and cooling to obtain the second-stage masterbatch; Final refining step: the second-stage masterbatch is internally kneaded with insoluble sulfur, accelerator, vulcanizing agent, anti-scorch agent and anti-vulcanization reversion agent, and the rubber is obtained after refining and cooling.

7. A tire, characterized in that: The tire is made of the high thermal conductivity and low heat generation rubber according to any one of claims 1 to 5.

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