High-strength liquid reversion reclaimed rubber

Abstract

The invention relates to the technical field of reclaimed rubber, and discloses high-strength liquid-state reversion reclaimed rubber, which is prepared by the following steps: step 1, preparing raw materials and performing crushing preparation work: accurately weighing each component material according to a formula; the rubber comprises the following components in parts by mass: 100 parts of liquid reversion reclaimed rubber, 10-20 parts of natural rubber, 20-30 parts of carbon black, 5-10 parts of white carbon black, 1-3 parts of a silane coupling agent, 5-10 parts of an aromatic oil plasticizer, 1-2 parts of a 4010NA anti-aging agent, 1-2 parts of a sulfur vulcanizing agent, 0.5-1 part of a CZ accelerant, 3-5 parts of zinc oxide and 1-2 parts of stearic acid. The addition of the natural rubber is one of key factors for improving mechanical properties. The natural rubber has excellent tensile strength and elasticity, and a proper amount of natural rubber is added into the liquid-state reversion reclaimed rubber, so that the reclaimed rubber can bear larger tensile force in the stretching process and can better restore to the original shape after being stressed and deformed.

Description

Technical Field

[0001] The present invention relates to the technical field of recycled rubber, and in particular to a high-strength liquid revert recycled rubber. Background Art

[0002] Liquid revert recycled rubber is a new material for recycling waste rubber resources, which improves environmental protection and reduces material costs. However, it has the following disadvantages and deficiencies:

[0003] Relatively weak mechanical properties:

[0004] Insufficient tensile strength and elasticity: Compared with virgin rubber materials such as natural rubber or synthetic rubber, the liquid revert recycled rubber has a lower tensile strength and may not meet the requirements in application scenarios that require bearing large tensile forces or stresses. Its elasticity is also poor, and after repeated stretching or deformation, its ability to return to its original state is weak, which will affect the service life and performance of rubber products.

[0005] Poor tear resistance: During use, liquid revert recycled rubber products are prone to tearing. This is because in the desulfurization process of recycled rubber, there may be problems such as uneven mixing and poor dispersion of the regenerant, resulting in an uneven internal structure and affecting the tear resistance performance.

[0006] Processing performance needs to be improved:

[0007] Difficult to control viscosity: Although liquid revert recycled rubber has a certain fluidity, in actual processing, the control of its viscosity is still a challenge. Viscosity is affected by various factors such as temperature and the addition amount of chemical modifiers. If the viscosity is not controlled properly, it will affect the production efficiency and quality of rubber products.

[0008] Limited compatibility with other materials: Although chemical modification and other treatments can improve the compatibility of liquid revert recycled rubber with the main rubber, in some applications with special requirements, its compatibility with other rubber additives, fillers or reinforcing materials is still not ideal enough, and additional surface treatment or addition of compatibilizers may be required to improve it.

[0009] Poor stability and durability:

[0010] Limited aging resistance: After the regeneration treatment, the molecular structure of liquid revert recycled rubber has changed, resulting in a decline in its aging resistance compared to virgin rubber. When exposed to environmental factors such as ultraviolet rays, oxygen, and heat for a long time, it is prone to aging, hardening, embrittlement, etc., leading to a decline in the performance of rubber products.

[0011] Poor high-temperature stability: At higher temperatures, the performance of liquid revert recycled rubber will be greatly affected, and problems such as softening and flowing may occur, which limits its application in high-temperature environments.

[0012] Large fluctuations in quality and performance:

[0013] Great influence of raw materials: The quality and performance of liquid reclaim rubber are greatly affected by the raw materials of waste rubber. Waste rubbers from different sources and of different types have differences in composition and performance, which will lead to unstable quality and performance of the produced liquid reclaim rubber.

[0014] High requirements for production process: The production process of liquid reclaim rubber is relatively complex and requires precise control of parameters in each link, such as desulfurization temperature, addition amount of chemical modifier and reaction time, etc. If the control in the production process is improper, it is easy to cause unstable product performance.

[0015] This case is proposed to solve or improve at least one of the disadvantages or deficiencies in the existing technology. Summary of the Invention

[0016] The present invention is achieved by adopting the following technical solutions:

[0017] A high-strength liquid reclaim rubber, comprising the following component raw materials (by mass parts);

[0018] Liquid reclaim rubber: 100 parts;

[0019] Natural rubber: 10 parts - 20 parts;

[0020] Carbon black: 20 parts - 30 parts;

[0021] Silica: 5 parts - 10 parts;

[0022] Silane coupling: 1 part - 3 parts;

[0023] Plasticizer: 5 parts 10 parts;

[0024] Antioxidant: 1 part 2 parts;

[0025] Vulcanizing agent: 1 part - 2 parts;

[0026] Accelerator: 0.5 part - 1 part;

[0027] Zinc oxide: 3 parts - 5 parts;

[0028] Stearic acid: 1 part - 2 parts.

[0029] Among them, the plasticizer adopts aromatic oil, the antioxidant adopts 4010N, the vulcanizing agent adopts sulfur, and the accelerator adopts dibenzothiazole disulfide .

[0030] And its preparation process includes the following steps:

[0031] Step 1: Raw material preparation and crushing

[0032] Preparation: Accurately weigh each component material according to the formula, namely 100 parts by mass of liquid reclaimed rubber, 10-20 parts by mass of natural rubber, 20-30 parts by mass of carbon black, 5-10 parts by mass of white carbon black, 1-3 parts by mass of silane coupling agent, 5-10 parts by mass of aromatic oil plasticizer, 1-2 parts by mass of 4010NA antioxidant, 1-2 parts by mass of sulfur vulcanizing agent, 0.5-1 parts by mass of CZ accelerator, 3-5 parts by mass of zinc oxide, and 1-2 parts by mass of stearic acid.

[0033] Crushing: Put the blocky natural rubber and liquid reclaimed rubber into the rubber crusher for crushing. The size of the crushed rubber particles is controlled at about 2-5 mm for subsequent mixing and processing.

[0034] Step 2: Mixing (stirring)

[0035] Primary mixing:

[0036] Add the crushed liquid reclaimed rubber and natural rubber particles into the internal mixer. Start the internal mixer, set the stirring speed to 30-40 rpm, and control the temperature at 50-60°C. Premix the rubber in the internal mixer for 3-5 minutes to make the two rubbers initially mixed evenly.

[0037] Slowly add carbon black and white carbon black in turn, and continue stirring for 10-15 minutes. During the addition process, the stirring speed can be appropriately increased to 40-50 rpm to ensure that carbon black and white carbon black can be fully dispersed in the rubber. At this time, the temperature will rise due to frictional heat, and the temperature should be controlled not to exceed 80°C.

[0038] Then add silane coupling agent, plasticizer (aromatic oil), antioxidant (4010NA), zinc oxide and stearic acid, stir for 8-10 minutes, maintain the stirring speed at 40-50 rpm, and control the temperature at 70-80°C to evenly disperse the additives in the rubber.

[0039] Secondary mixing: The rubber compound after primary mixing is transferred to the open mill for secondary mixing. The roller distance of the open mill is set to 1-2 mm, and the roller temperature is controlled at 40-50°C. The uniformity of the rubber compound is further improved through multiple thin passes and triangular packing operations. The mixing time is about 10-15 minutes.

[0040] Step 3: Preliminary processing of desulfurization extruder

[0041] Put the twice - kneaded rubber compound into the desulfurization extruder. Set the screw speed of the desulfurization extruder to 20 - 30 revolutions per minute, and control the barrel temperature in sections: the temperature of zone 1 is 100 - 120 °C, the temperature of zone 2 is 120 - 140 °C, the temperature of zone 3 is 140 - 160 °C, and the head temperature is 160 - 180 °C. The rubber compound is preliminarily desulfurized and plasticized in the desulfurization extruder. The width of the extruded rubber strip is controlled within 30 - 50 mm, and the thickness is controlled within 5 - 10 mm.

[0042] Step Four: Final Processing in the Desulfurization Tank

[0043] Put the rubber strip extruded from the desulfurization extruder into the desulfurization tank. Introduce steam into the desulfurization tank to make the pressure in the tank reach 1.2 - 1.5 MPa, control the temperature at 180 - 200 °C, and maintain this condition for 3 - 5 hours for deep desulfurization and cross - linking reaction.

[0044] After the reaction ends, slowly release the pressure in the desulfurization tank. After the pressure drops to atmospheric pressure, open the desulfurization tank and take out the rubber compound.

[0045] Step Five: Vulcanization and Molding

[0046] Put the rubber compound treated in the desulfurization tank into the open mill again, add vulcanizing agent (sulfur) and accelerator (CZ), and knead for 8 - 10 minutes at a roll temperature of 40 - 50 °C to make the vulcanizing agent and accelerator evenly dispersed in the rubber compound.

[0047] Put the kneaded rubber compound into the mold and carry out vulcanization and molding on the flat vulcanizer. The vulcanization temperature is set at 150 - 160 °C, the pressure is 10 - 15 MPa, and the vulcanization time depends on the thickness and shape of the product, generally 10 - 30 minutes.

[0048] Step Six: Post - treatment

[0049] Take out the vulcanized rubber product from the mold and carry out post - treatment processes such as trimming and inspection, remove the excess scraps, and check whether the appearance and performance of the product meet the requirements.

[0050] The advantages and positive effects of the present invention are:

[0051] 1. Enhance tensile strength and elasticity: The addition of natural rubber is one of the key factors to improve mechanical properties. Natural rubber itself has excellent tensile strength and elasticity. Adding an appropriate amount of natural rubber to the liquid - reverted recycled rubber can enable the recycled rubber to withstand greater tensile force during the stretching process and can better return to its original state after being deformed by force, enhancing the overall flexibility and tear resistance of the recycled rubber, making the rubber product more durable and suitable for application scenarios with high requirements for mechanical properties.

[0052] 2. Improving hardness and wear resistance: Carbon black and silica play important roles as reinforcing agents. They are evenly dispersed in the rubber matrix, form a tight bond with rubber molecules, and increase the hardness and wear resistance of the rubber. This enables rubber products produced with this formulation to maintain good performance in friction and wear environments, extending the service life of the products. For example, the application effect is remarkable in products such as tires and shoe soles that require wear resistance.

[0053] 3. Reducing viscosity and improving fluidity: The addition of plasticizers (such as aromatic oil) effectively reduces the viscosity of the liquid reversion recycled rubber and improves its fluidity. This makes it easier to operate the rubber during processing such as mixing and molding, reduces processing difficulty and energy consumption, and improves production efficiency. At the same time, the plasticizer also helps the uniform dispersion of other additives in the rubber, ensuring the stability of product quality. Specific implementation mode

[0054] A high-strength liquid reversion recycled rubber comprises the following component raw materials (by mass parts);

[0055] Liquid recycled rubber: 100 parts;

[0056] Natural rubber: 10 parts - 20 parts;

[0057] Carbon black: 20 parts - 30 parts;

[0058] Silica: 5 parts - 10 parts;

[0059] Silane coupling: 1 part - 3 parts;

[0060] Plasticizer: 5 parts - 10 parts;

[0061] Antioxidant: 1 part - 2 parts;

[0062] Vulcanizing agent: 1 part - 2 parts;

[0063] Accelerator: 0.5 part - 1 part;

[0064] Zinc oxide: 3 parts - 5 parts;

[0065] Stearic acid: 1 part - 2 parts.

[0066] Among them, the plasticizer uses aromatic oil, the antioxidant uses 4010N, the vulcanizing agent uses sulfur, and the accelerator uses dibenzothiazole disulfide .

[0067] And its preparation process includes the following steps:

[0068] Step 1: Raw material preparation and pulverization

[0069] Preparation: Accurately weigh each component material according to the formula, namely 100 parts by mass of liquid reclaimed rubber, 10-20 parts by mass of natural rubber, 20-30 parts by mass of carbon black, 5-10 parts by mass of white carbon black, 1-3 parts by mass of silane coupling agent, 5-10 parts by mass of aromatic oil plasticizer, 1-2 parts by mass of 4010NA antioxidant, 1-2 parts by mass of sulfur vulcanizing agent, 0.5-1 parts by mass of CZ accelerator, 3-5 parts by mass of zinc oxide, and 1-2 parts by mass of stearic acid.

[0070] Crushing: Put the blocky natural rubber and liquid reclaimed rubber into the rubber crusher for crushing. The size of the crushed rubber particles is controlled at about 2-5 mm for subsequent mixing and processing.

[0071] Step 2: Mixing (stirring)

[0072] Primary mixing:

[0073] Add the crushed liquid reclaimed rubber and natural rubber particles into the internal mixer. Start the internal mixer, set the stirring speed to 30-40 rpm, and control the temperature at 50-60°C. Premix the rubber in the internal mixer for 3-5 minutes to make the two rubbers initially mixed evenly.

[0074] Slowly add carbon black and white carbon black in turn, and continue stirring for 10-15 minutes. During the addition process, the stirring speed can be appropriately increased to 40-50 rpm to ensure that carbon black and white carbon black can be fully dispersed in the rubber. At this time, the temperature will rise due to frictional heat, and the temperature should be controlled not to exceed 80°C.

[0075] Then add silane coupling agent, plasticizer (aromatic oil), antioxidant (4010NA), zinc oxide and stearic acid, stir for 8-10 minutes, maintain the stirring speed at 40-50 rpm, and control the temperature at 70-80°C to evenly disperse the additives in the rubber.

[0076] Secondary mixing: The rubber compound after primary mixing is transferred to the open mill for secondary mixing. The roller distance of the open mill is set to 1-2 mm, and the roller temperature is controlled at 40-50°C. The uniformity of the rubber compound is further improved through multiple thin passes and triangular packing operations. The mixing time is about 10-15 minutes.

[0077] Step 3: Preliminary processing of desulfurization extruder

[0078] Put the twice - kneaded rubber compound into the desulfurization extruder. Set the screw speed of the desulfurization extruder at 20 - 30 revolutions per minute. The barrel temperature is controlled in sections: the temperature of zone 1 is 100 - 120 °C, the temperature of zone 2 is 120 - 140 °C, the temperature of zone 3 is 140 - 160 °C, and the head temperature is 160 - 180 °C. The rubber compound undergoes preliminary desulfurization and plasticization in the desulfurization extruder. The width of the extruded rubber strip is controlled at 30 - 50 mm, and the thickness is controlled at 5 - 10 mm.

[0079] Step Four: Final Processing of the Desulfurization Tank

[0080] Put the rubber strip extruded from the desulfurization extruder into the desulfurization tank. Introduce steam into the desulfurization tank to make the pressure in the tank reach 1.2 - 1.5 MPa, and control the temperature at 180 - 200 °C. Maintain this condition for 3 - 5 hours for deep desulfurization and cross - linking reaction.

[0081] After the reaction ends, slowly release the pressure in the desulfurization tank. After the pressure drops to atmospheric pressure, open the desulfurization tank and take out the rubber compound.

[0082] Step Five: Vulcanization and Molding

[0083] Put the rubber compound processed by the desulfurization tank back into the open mill, add vulcanizing agent (sulfur) and accelerator (CZ), and knead for 8 - 10 minutes at a roll temperature of 40 - 50 °C to make the vulcanizing agent and accelerator evenly disperse in the rubber compound.

[0084] Put the kneaded rubber compound into a mold and perform vulcanization and molding on a flat vulcanizer. Set the vulcanization temperature at 150 - 160 °C, the pressure at 10 - 15 MPa, and the vulcanization time depends on the thickness and shape of the product, generally 10 - 30 minutes.

[0085] Step Six: Post - treatment

[0086] Take out the vulcanized rubber product from the mold and perform post - treatment processes such as trimming and inspection, remove the excess scraps, and check whether the appearance and performance of the product meet the requirements.

[0087] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the embodiments described in the specific implementation manners. Any other implementation manners obtained by those skilled in the art according to the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A formula for preparing rubber from liquid recycled reclaimed rubber, characterized in that, The following ingredients are included by weight: 100 parts of liquid regenerated rubber, 10-20 parts of natural rubber, 20-30 parts of carbon black, 5 -10 parts of white carbon black, 1-3 parts of silane coupling agent, 5-10 parts of aromatic oil plasticizer, 1-2 parts of 4010NA antioxidant, 1-2 parts of sulfur vulcanizing agent, 0.5-1 parts of CZ accelerator, 3-5 parts of zinc oxide, 1 -2 parts of stearic acid.

2. The formula for preparing rubber from liquid recycled reclaimed rubber according to claim 1, wherein, The natural rubber is one or more of standard rubber and concentrated latex.

3. The formulation for preparing rubber from liquid recycled reclaimed rubber according to claim 2, wherein The carbon black is one or more of N220, N330, N550 or N660.

4. The formula for preparing rubber from liquid reclaimed rubber according to claim 3, characterized in that, The white carbon black is precipitated white carbon black or fumed white carbon black.

5. A process for preparing rubber using the formulation according to any one of claims 1-4, characterized in that, The following steps are involved: Crushing the blocky natural rubber and liquid reclaimed rubber into particles of 2-5 mm; Primary mixing: add the crushed liquid reclaimed rubber and natural rubber particles into the internal mixer, stir at 30-40 rpm, control the temperature at 50-60°C, and premix for 3-5 minutes; add carbon black and white carbon black in turn, stir at 40-50 rpm for 10-15 minutes, and the temperature should not exceed 80°C; then add silane coupling agent, aromatic oil plasticizer, 4010NA antioxidant, zinc oxide and stearic acid, stir at 40-50 rpm for 8-10 minutes, and control the temperature at 70-80°C; Secondary mixing: Transfer the primary mixed rubber to the open mixer, set the roller distance to 1-2 mm, and the roller temperature to 40 -50℃, mix for 10-15 minutes by multiple thin passes and triangle packing operations; Put the secondary mixed rubber into the desulfurization extruder, the screw speed is 20-30 rpm, the temperature of the first zone of the barrel is 100-120℃, the temperature of the second zone is 120-140℃, the temperature of the third zone is 140-160℃, the temperature of the die head is 160-180℃, the width of the extruded rubber strip is 30-50 mm, and the thickness is 5-10 mm; Put the extruded rubber strip into the desulfurization tank, introduce steam to make the pressure reach 1.2-1.5MPa, control the temperature at 180-200℃, and keep it for 3-5 hours; Put the rubber compound treated in the desulfurization tank into the open mill, add sulfur vulcanizer and CZ accelerator, and mix for 8-10 minutes at a roller temperature of 40-50℃; Put the mixed rubber into the mold and vulcanize on a flat vulcanizer at a temperature of 150-160°C and a pressure of 10-15MPa for 10-30 minutes; Trim and inspect the rubber products after vulcanization.

6. The process for preparing rubber according to claim 5, characterized in that, The pulverization is carried out by using a rubber pulverizer.