High-weather-resistance rubber balance block and preparation method thereof

Abstract

The invention relates to the technical field of functional rubber, in particular to a high-weather-resistance rubber balance block and a preparation method thereof. The high-weather-resistance rubber balance block is prepared from the following components in parts by weight: 65 to 75 parts of ethylene propylene diene monomer (EPDM), 25 to 35 parts of natural rubber (NR), 5.0 to 6.5 parts of zinc stearate, 1.5 to 2.5 parts of anti-aging agent, 0.8 to 1.0 part of sulfur, 0.3 to 0.9 part of accelerant, 1.0 to 1.5 parts of alkylphenol disulfide, 5 to 10 parts of plasticizer, 40 to 60 parts of filler and 2 to 4 parts of composite siloxane coupling agent. The composite siloxane coupling agent is prepared from 3-butene triethoxy silane, bicyclo [2.2. 1]-5-heptylene-2-yl triethoxy silane, and bis-[3-(triethoxy silicon) propyl]-tetrasulfide. The rubber balance block prepared by the invention has excellent ozone aging cracking resistance, and does not crack in an aging test for 48 hours under the ozone concentration of 200PPHM.

Description

Technical Field

[0001] This invention relates to the field of functional rubber technology, and in particular to a high weather-resistant rubber balance block and its preparation method. Background Technology

[0002] Tire balance weights are used to balance automobile tires. Common materials used in the production of tire balance weights are natural rubber (NR) and neoprene rubber (CR). Natural rubber (NR) is the most commonly used material in early tire balance weights due to its low cost, ease of processing, and stable physical properties. However, its poor weather resistance and chemical resistance no longer meet the weather resistance requirements of automakers. Neoprene rubber (CR) is an upgraded version of NR, possessing excellent weather and chemical resistance. However, the physical properties of CR result in process deviations during mixing and vulcanization, and its price is relatively high compared to other materials. Therefore, it is currently only used in some special vehicle models.

[0003] To improve the weather resistance of natural rubber (NR), existing technologies typically use ethylene propylene diene monomer (EPDM) rubber to modify NR for weather resistance. EPDM, as a highly saturated rubber, possesses excellent heat resistance, ozone resistance, acid and alkali resistance, weathering resistance, fatigue resistance, and tear resistance. EPDM / NR rubber compositions optimize ozone resistance, weather resistance, oil resistance, and aging resistance, while also improving scorch resistance and bloom resistance. However, the double bond reactivity in EPDM is higher than that in NR, and differences in vulcanization during EPDM / NR blending can lead to a decrease in mechanical properties and tear resistance. Furthermore, the difference in polarity between fillers in EPDM / NR compositions and those in EPDM and NR results in inconsistent filler dispersion uniformity, meaning that the ozone aging resistance and mechanical properties of EPDM / NR rubber compositions require further improvement.

[0004] To this end, the inventors have provided a high weather-resistant rubber balance block and its preparation method. Summary of the Invention

[0005] To improve the ozone aging resistance and mechanical properties of existing EPDM / NR rubber compositions, this invention provides a high weather-resistant rubber balance block and its preparation method.

[0006] The present invention provides a high weather-resistant rubber balance block, which is achieved through the following technical solution:

[0007] A high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 65-75 parts of ethylene propylene diene monomer (EPDM), 25-35 parts of natural rubber (NR), 5.0-6.5 parts of zinc stearate, 1.5-2.5 parts of antioxidant, 0.8-1.0 parts of sulfur, 0.3-0.9 parts of accelerator, 1.0-1.5 parts of alkylphenol disulfide, 5-10 parts of plasticizer, and 40-60 parts of... The filler and 2-4 parts of composite siloxane coupling agent; the filler is obtained by surface modification treatment with composite siloxane coupling agent; the composite siloxane coupling agent is composed of 3-butenetriethoxysilane, bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and bis-[3-(triethoxysilyl)propyl]-tetrasulfide in a mass ratio of (25-35):(65-75):(80-120).

[0008] In this invention, the filler is surface-modified by a composite siloxane coupling agent. The resulting filler has little polarity difference with EPDM and NR. The filler surface-modified by the composite siloxane coupling agent can be uniformly dispersed inside the EPDM / NR matrix, effectively improving the mechanical properties and ozone aging crack resistance of the rubber balance block. It does not crack after 48 hours of aging test at 200 PPHM ozone concentration, thus expanding its application range.

[0009] Preferably, the filler is a mixture of carbon black, flake nanofiller, and aramid nanofiber in a mass ratio of (60-85):(20-35):(3-6).

[0010] Preferably, the sheet-like nanofiller is at least one of hydroxyl-modified graphene, boron nitride nanosheets, and molybdenum disulfide nanosheets.

[0011] This invention uses sheet-like nanofillers, which are uniformly dispersed inside the EPDM / NR matrix. These nanofillers can form a barrier layer inside the rubber, effectively reducing ozone penetration and improving the ozone aging crack resistance, air tightness, and heat stability of the rubber balance block.

[0012] In this invention, aramid nanofibers are used. The aramid nanofibers are uniformly dispersed inside the EPDM / NR matrix, which can effectively improve the mechanical properties, fatigue resistance, and tear resistance of rubber.

[0013] In summary, the filler system composed of carbon black, flake nanofillers, and aramid nanofibers is uniformly dispersed within the EPDM / NR matrix, thereby improving the mechanical properties, fatigue resistance, tear resistance, ozone aging cracking resistance, air tightness, and heat stability of the rubber balance block. This also improves the ozone aging resistance and mechanical properties of existing EPDM / NR rubber compositions, expanding their application range.

[0014] Preferably, the surface modification treatment method for carbon black is as follows: weigh carbon black and composite siloxane coupling agent at a mass ratio of 10:(0.5-1) and place them in a kneader, then knead them at 40-60℃ for 15-30 minutes.

[0015] Preferably, the surface modification treatment method of the sheet-like nanofiller is as follows: boron nitride nanosheets are dispersed in an organic solvent to form a suspension, and a composite siloxane coupling agent is added dropwise to the suspension at a rotation speed of 100-400 rpm. The mass ratio of the composite siloxane coupling agent to the boron nitride nanosheets is (0.5-1):10. After the addition is completed, the mixture is ultrasonically dispersed for 15-60 min, and the wet material obtained after vacuum filtration is vacuum dried.

[0016] Preferably, the surface modification treatment method of the aramid nanofibers is as follows: the aramid nanofibers are dispersed in an organic solvent to form a suspension, and diisocyanate is added dropwise to the suspension at a speed of 100-400 rpm for surface NCO modification treatment. The mass ratio of the diisocyanate to the aramid nanofibers is (0.5-2):100. Subsequently, a composite siloxane coupling agent is added dropwise to the suspension at a speed of 100-400 rpm. After the addition is completed, the mixture is ultrasonically dispersed for 15-60 min, and the wet material obtained after vacuum filtration is vacuum dried.

[0017] Preferably, the accelerator is at least one of the following accelerators: ZDEC, ZDMC, TETD, TMTD, CBS, and NOBS.

[0018] More preferably, the accelerator is a mixture of accelerators ZDEC, TETD, and CBS in a mass ratio of (6-8):(2-4):(2-4).

[0019] The accelerator composition, which is a blend of accelerators ZDEC, TETD, and CBS, imparts good scorch safety, after-effect, and vulcanization flatness to the rubber balance block, thereby improving the processability and product performance consistency of the rubber balance block.

[0020] Preferably, the antioxidant is at least one of antioxidants 4010NA, IPPD, AW, 264, and DNP.

[0021] More preferably, the antioxidant is a compound of 4010NA and 264 in a mass ratio of (6-8):(2-4).

[0022] By combining antioxidants 4010NA and 264, the ozone aging and cracking resistance of rubber balance blocks can be improved.

[0023] Preferably, the plasticizer is at least one of paraffin oil, naphthenic oil, and white oil.

[0024] The present invention provides a method for preparing a high weather-resistant rubber balance block, which is achieved through the following technical solution:

[0025] A method for preparing a high weather-resistant rubber balance block includes the following steps:

[0026] Step 1: The surface of the filler is modified using a composite siloxane coupling agent to obtain the finished filler.

[0027] Step 2: Pulverize the accurately measured EPDM rubber and natural rubber at 30±5 r / min for 3-5 min, then add the accurately measured finished filler, antioxidant and plasticizer and mix them together. Then, mix them at 70±5℃ for 10-15 min, then pass them through a thin pass 3-5 times and then open the mill to obtain the primary compound.

[0028] Step 3: Add zinc stearate, sulfur, accelerator, and alkylphenol disulfide to the compound, and start milling at 100-120℃ for 3-5 minutes. Let it stand at room temperature for 18-24 hours to obtain the finished compound. The obtained finished compound is molded into a pre-form. The pre-form is then vulcanized at a temperature of 170-180℃ for 4-6 minutes to obtain a high weather-resistant rubber balance block.

[0029] In summary, the present invention has the following advantages:

[0030] 1. The rubber balance block prepared by this invention has excellent resistance to ozone aging and cracking and good mechanical properties. It does not crack after 48 hours of aging test at an ozone concentration of 200 PPHM, thus expanding its application range.

[0031] 2. The preparation method provided by this invention is relatively simple and the process is mature, which facilitates industrial production and manufacturing, thereby reducing the overall production cost, enhancing the economic competitiveness of the product, and facilitating market promotion. Detailed Implementation

[0032] To further understand the inventiveness and technical advancements of this invention, the preferred embodiments of this invention will be discussed in detail below with reference to examples and comparative examples.

[0033] Example: A high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 65-75 parts of ethylene propylene diene monomer (EPDM), 25-35 parts of natural rubber (NR), 5.0-6.5 parts of zinc stearate, 1.5-2.5 parts of antioxidant, 0.8-1.0 parts of sulfur, 0.3-0.9 parts of accelerator, 1.0-1.5 parts of alkylphenol disulfide, 5-10 parts of plasticizer, 40-60 parts of filler, and 2-4 parts of composite siloxane coupling agent.

[0034] Ethylene propylene diene monomer (EPDM) rubber can be selected from high ENB content (ENB≥5.0%) such as Kumho KEP350 from South Korea, Mitsui Chemicals X-4010, Dow 4770P from the United States, and Arlanxnetech Keltan 10675C DE.

[0035] The natural rubber NR is SCR20 (No. 20 standard rubber) supplied by Hebei Mingxiang New Material Technology Co., Ltd.

[0036] The accelerator is at least one selected from ZDEC, ZDMC, TETD, TMTD, CBS, and NOBS. Preferably, the accelerator is a mixture of ZDEC, TETD, and CBS in a mass ratio of (6-8):(2-4):(2-4). More preferably, the accelerator is a mixture of ZDEC, TETD, and CBS in a mass ratio of 6:2:2.

[0037] The antioxidant is at least one of antioxidant 4010NA, IPPD, AW, 264, and DNP. Preferably, the antioxidant is a mixture of antioxidant 4010NA and antioxidant 264 in a mass ratio of (6-8):(2-4).

[0038] The plasticizer is at least one of paraffin oil, naphthenic oil, and white oil, preferably paraffin oil.

[0039] The composite siloxane coupling agent comprises 3-butenetriethoxysilane (Anhui Silicon Innovation Materials Technology Co., Ltd., CAS: 57813-67-9), bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane (CAS: 18401-43-9, Beijing Bailingwei Technology Co., Ltd.), and bis-[3-(triethoxysilyl)propyl]-tetrasulfide (CAS: 40372-72-3, Shanghai Yi'en Chemical Technology Co., Ltd.) in a mass ratio of (25-35):(65-75):(80-120).

[0040] The filler is a compound of carbon black, sheet-like nanofiller, and aramid nanofiber in a mass ratio of (60-85):(20-35):(3-6). The sheet-like nanofiller is at least one of hydroxyl-modified graphene, boron nitride nanosheets, and molybdenum disulfide nanosheets.

[0041] The surface modification treatment method for carbon black is as follows: weigh carbon black and composite siloxane coupling agent at a mass ratio of 10:(0.5-1) and place them in a kneader. Knead them at 40-60℃ for 15-30 minutes.

[0042] The surface modification treatment method for sheet-like nanofillers is as follows: boron nitride nanosheets are dispersed in an organic solvent to form a suspension. A composite siloxane coupling agent is added dropwise to the suspension at a rotation speed of 100-400 rpm. The mass ratio of the composite siloxane coupling agent to the boron nitride nanosheets is (0.5-1):10. After the addition is completed, the mixture is ultrasonically dispersed for 15-60 min. The wet material obtained after vacuum filtration is then vacuum dried.

[0043] The surface modification treatment method of aramid nanofibers is as follows: Aramid nanofibers are dispersed in an organic solvent to form a suspension. Diisocyanate is added dropwise to the suspension at a speed of 100-400 rpm for surface NCO modification treatment. The mass ratio of diisocyanate to aramid nanofibers is (0.5-2):100. Subsequently, a composite siloxane coupling agent is added dropwise to the suspension at a speed of 100-400 rpm. After the addition is completed, ultrasonic dispersion is performed for 15-60 min. The wet material obtained after vacuum filtration is then vacuum dried.

[0044] A method for preparing a high weather-resistant rubber balance block includes the following steps:

[0045] Step 1: The surface of the filler is modified using a composite siloxane coupling agent to obtain the finished filler.

[0046] Step 2: Pulverize the accurately measured EPDM rubber and natural rubber at 30±5 r / min for 3-5 min, then add the accurately measured finished filler, antioxidant and plasticizer and mix them together. Then, mix them at 70±5℃ for 10-15 min, then pass them through a thin pass 3-5 times and then open the mill to obtain the primary compound.

[0047] Step 3: Add zinc stearate, sulfur, accelerator, and alkylphenol disulfide to the compound, and start milling at 100-120℃ for 3-5 minutes. Let it stand at room temperature for 18-24 hours to obtain the finished compound. The obtained finished compound is molded into a pre-form. The pre-form is then vulcanized at a temperature of 170-180℃ for 6-8 minutes to obtain a high weather-resistant rubber balance block.

[0048] Preparation Example 1: The preparation method of aramid nanofibers is as follows: 6.0g of aramid fiber 1414 (Shandong Huacai Aramid Materials Technology Co., Ltd.) and 3.0g of potassium hydroxide were added to 350mL of dimethyl sulfoxide solution, and 10.0mL of deionized water was added. The solution was then dissolved at 600rpm / 80℃ for 48h to obtain a dark red 2% aramid solution. Subsequently, under high-speed shearing, deionized water was added dropwise at a rate of 50mL / h to dilute to 0.5%. Dimethyl sulfoxide and other impurity ions were removed by dialyzing. Finally, after three high-pressure homogenization treatments at 150MPa, an aqueous dispersion of ANFs with a solid content of 0.5wt% was obtained. The water was removed by vacuum distillation to obtain aramid nanofiber powder.

[0049] Example 1: A high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of ethylene propylene diene monomer (EPDM) rubber (Allantech Keltan 10675C). DE), 30 parts natural rubber NR (SCR20, Hebei Mingxiang New Material Technology Co., Ltd.), 6 parts zinc stearate (Guangdong Wengjiang Chemical Reagent Co., Ltd., CAS: 557-05-1), 1.5 parts antioxidant 4010NA (Hubei Zhonglong Kang Sheng Fine Chemical Co., Ltd., CAS: 101-72-4), 0.5 parts antioxidant 264 (Wuxi Qianfeng Chemical Technology Co., Ltd., CAS: 128-37-0), 1.0 part sulfur (Hubei Zhonglong Kang Sheng Fine Chemical Co., Ltd., CAS: 9035-99-8, insoluble sulfur), 0.36 parts accelerator ZDEC (Hubei Zhonglong Kang Sheng Fine Chemical Co., Ltd., CAS: 14324-55-1), 0.12 parts accelerator TETD (Hubei Zhonglong Kang Sheng Fine Chemical Co., Ltd., CAS: 97-77-8), 0.12 parts accelerator CBS (Hubei Zhonglong Kang Sheng Fine Chemical Co., Ltd., CAS: 95-33-0), 1.2 parts alkylphenol disulfide (Nantong Runfeng Petrochemical Co., Ltd., CAS: 60303-68-6), 7.5 parts paraffin oil (liquid paraffin, CAS: 8012-95-1, Nanjing Chemical Reagent Co., Ltd.), 32 parts carbon black (Cabot N550, Shandong Guiquan Ecological Technology Co., Ltd.), 16 parts sheet-like nanofiller - boron nitride nanosheets (Hangzhou Jiupeng New Materials Co., Ltd., model CY-HBN), 2 parts... Example 1 contains aramid nanofibers, 0.3 parts of 3-butenetriethoxysilane (Anhui Silicon Innovation Materials Technology Co., Ltd., CAS: 57813-67-9), 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane (CAS: 18401-43-9, Beijing Bailingwei Technology Co., Ltd.), and 1 part of bis-[3-(triethoxysilane)propyl]-tetrasulfide (CAS: 40372-72-3, Shanghai Yi'en Chemical Technology Co., Ltd.).

[0050] A method for preparing a high weather-resistant rubber balance block includes the following steps:

[0051] Step 1: The surface of the filler is modified using a composite siloxane coupling agent to obtain the finished filler.

[0052] Surface treatment process of carbon black: 3-butenetriethoxysilane, dicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and bis-[3-(triethoxysilane)propyl]-tetrasulfide are mixed evenly in a mass ratio of 3:7:10 to obtain a composite siloxane coupling agent. 32 parts of carbon black and 1.6 parts of composite siloxane coupling agent are weighed and placed in a kneader. The mixture is kneaded at 45°C and 30 r / min for 15 min to obtain the finished carbon black.

[0053] The surface modification treatment method of boron nitride nanosheets is as follows: 3-butenetriethoxysilane, bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and bis-[3-(triethoxysilane)propyl]-tetrasulfide are mixed evenly in a mass ratio of 3:7:10 to obtain a composite siloxane coupling agent. 16 parts of boron nitride nanosheets CY-HBN are ultrasonically dispersed in 200 parts of acetone to form a CY-HBN suspension. 0.8 parts of the composite siloxane coupling agent are added dropwise to the CY-HBN suspension at a speed of 200 rpm. After the composite siloxane coupling agent is added, ultrasonic dispersion is performed for 30 min at an ultrasonic frequency of 40 kHz and an ultrasonic power of 600 W. The mixture is then filtered under reduced pressure and rinsed three times with deionized water during the filtration process. The resulting wet material is placed in a vacuum drying oven for 6 h of vacuum drying at a drying temperature of 105℃ / 100 Pa. After cooling to room temperature, the finished boron nitride nanosheets are obtained.

[0054] The surface modification method for aramid nanofibers is as follows: Two parts of the aramid nanofibers from Preparation Example 1 were ultrasonically dispersed in 200 parts of dimethyl sulfoxide solution and 50 parts of acetone to form a suspension. The temperature was adjusted to 90℃, and 0.02 parts of isophorone diisocyanate (Yantai Wanhua) were added dropwise to the suspension at 200 rpm. After the isophorone diisocyanate was added, the reaction was continued at 90℃ / 200 rpm for 60 min to obtain NCO-modified ANFs. Subsequently, 0.1 parts of composite siloxane coupling agent were added dropwise to the suspension at 200 rpm. A composite siloxane coupling agent (3-butenetriethoxysilane, bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and bis-[3-(triethoxysilane)propyl]-tetrasulfide were mixed evenly in a mass ratio of 3:7:10). After the agent was added dropwise, it was ultrasonically dispersed for 30 minutes at an ultrasonic frequency of 40 kHz and an ultrasonic power of 600 W. The mixture was then filtered under reduced pressure, and rinsed three times with deionized water during the filtration process. The resulting wet material was placed in a vacuum drying oven for 6 hours of vacuum drying at a temperature of 105 ℃ / 100 Pa. After cooling to room temperature, the finished aramid nanofibers were obtained.

[0055] Step 2: Place 70 parts of EPDM rubber and 30 parts of natural rubber in a mixer and plasticize at 30 r / min for 5 min. Then add the finished carbon black, finished boron nitride nanosheets and finished aramid nanofibers prepared in Step 1 and mix at 70°C for 10 min. Then add 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264 and 7.5 parts of paraffin oil and continue mixing at 70°C for 5 min. Then place the rubber compound in a two-roll mill, pass it through a thin mill 5 times, and then sheet it at 135°C to obtain the primary compound.

[0056] Step 3: The primary rubber compound is placed in an internal mixer and plasticized at 30 r / min for 5 min. 6 parts zinc stearate, 1.0 part sulfur, 0.36 parts accelerator ZDEC, 0.12 parts accelerator TETD, 0.12 parts accelerator CBS, and 1.2 parts alkylphenol disulfide are added to the compound. The mixture is then milled at 120℃ for 3 min and left to stand at room temperature for 24 h to obtain the finished rubber compound. The obtained finished rubber compound is then molded into a preform. The preform is then vulcanized at 170℃ for 285 s to obtain a high weather-resistant rubber balance block.

[0057] The difference between Example 2 and Example 1 is that: a high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of EPDM, 30 parts of natural rubber NR, 6 parts of zinc stearate, 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264, 1.0 part of sulfur, 0.60 parts of accelerator ZDEC, 1.2 parts of alkylphenol disulfide, 7.5 parts of paraffin oil, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, 2 parts of aramid nanofibers prepared in Example 1, 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0058] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 318s, while the other steps are the same.

[0059] The difference between Example 3 and Example 1 is that: A high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of EPDM, 30 parts of natural rubber NR, 6 parts of zinc stearate, 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264, 1.0 part of sulfur, 0.60 parts of accelerator TETD, 1.2 parts of alkylphenol disulfide, 7.5 parts of paraffin oil, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, 2 parts of aramid nanofibers prepared in Example 1, 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0060] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 309s, while the other steps are the same.

[0061] The difference between Example 4 and Example 1 is that: a high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of EPDM, 30 parts of natural rubber NR, 6 parts of zinc stearate, 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264, 1.0 part of sulfur, 0.60 parts of accelerator ZDEC, 0.30 parts of accelerator TETD, 1.2 parts of alkylphenol disulfide, 7.5 parts of paraffin oil, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, 2 parts of aramid nanofibers prepared in Example 1, 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0062] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 294s, while the other steps are the same.

[0063] The difference between Example 5 and Example 1 is that: A high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of EPDM, 30 parts of natural rubber NR, 6 parts of zinc stearate, 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264, 1.0 parts of sulfur, 0.30 parts of accelerator ZDEC, 0.15 parts of accelerator TETD, 0.15 parts of accelerator CBS, 1.2 parts of alkylphenol disulfide, 7.5 parts of paraffin oil, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, 2 parts of aramid nanofibers prepared in Example 1, 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0064] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 249s, while the other steps are the same.

[0065] The difference between Example 6 and Example 1 is that: a high weather-resistant rubber balance block is made from the following raw materials in parts by weight: 70 parts of EPDM, 30 parts of natural rubber NR, 6 parts of zinc stearate, 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264, 1.0 part of sulfur, 0.20 parts of accelerator ZDEC, 0.20 parts of accelerator TETD, 0.20 parts of accelerator CBS, 1.2 parts of alkylphenol disulfide, 7.5 parts of paraffin oil, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, 2 parts of aramid nanofibers prepared in Example 1, 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide.

[0066] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 302s, while the other steps are the same.

[0067] The difference between Comparative Example 1 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide were replaced with 2 parts of bis-[3-(triethoxysilyl)propyl]-tetrasulfide, while the other components remained unchanged.

[0068] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 242s, while the other steps are the same.

[0069] The difference between Comparative Example 2 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide were replaced with 2 parts of vinyltriethoxysilane (Hubei Zhonglong Kangcheng Fine Chemical Co., Ltd., CAS: 78-08-0), while the remaining components remained unchanged.

[0070] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 321s, while the other steps are the same.

[0071] The difference between Comparative Example 3 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide were replaced with 2 parts of 3-butenetriethoxysilane, while the other components remained unchanged.

[0072] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 315s, while the other steps are the same.

[0073] The difference between Comparative Example 4 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide were replaced with 2 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, while the other components remained unchanged.

[0074] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 324s, while the other steps are the same.

[0075] The difference between Comparative Example 5 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilyl)propyl]-tetrasulfide were replaced with 1 part of 3-butenetriethoxysilane and 1 part of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, while the other components remained unchanged.

[0076] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 306s, while the other steps are the same.

[0077] The difference between Comparative Example 6 and Example 1 is that 0.3 parts of 3-butenetriethoxysilane, 0.7 parts of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and 1 part of bis-[3-(triethoxysilane)propyl]-tetrasulfide were replaced with 1 part of bicyclo[2.2.1]-5-heptene-2-yltriethoxysilane and 1 part of bis-[3-(triethoxysilane)propyl]-tetrasulfide, while the other components remained unchanged.

[0078] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 301s, while the other steps are the same.

[0079] The difference between Comparative Example 7 and Example 1 is that 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, and 2 parts of aramid nanofibers from Preparation Example 1 were replaced with 50 parts of carbon black N550, while the other components remained unchanged.

[0080] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 272s, while the other steps are the same.

[0081] The difference between Comparative Example 8 and Example 1 is that 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, and 2 parts of aramid nanofibers from Preparation Example 1 were replaced with 34 parts of carbon black N550 and 16 parts of boron nitride nanosheets CY-HBN, while the other components remained unchanged.

[0082] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 278s, while the other steps are the same.

[0083] The difference between Comparative Example 9 and Example 1 is that 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, and 2 parts of aramid nanofibers from Preparation Example 1 were replaced with 48 parts of carbon black N550 and 2 parts of aramid nanofibers from Preparation Example 1, while the other components remained unchanged.

[0084] The difference in preparation method lies in step three, where the vulcanization temperature is 170℃ and the time is 275s, while the other steps are the same.

[0085] The difference between Comparative Example 10 and Example 1 is that the rubber balance block is produced by a one-step blending method.

[0086] The difference in the preparation methods of high weather-resistant rubber balance blocks lies in:

[0087] Step 1: 3-Butenetriethoxysilane, dicyclo[2.2.1]-5-heptene-2-yltriethoxysilane, and bis-[3-(triethoxysilane)propyl]-tetrasulfide are mixed uniformly at a mass ratio of 3:7:10 to obtain a composite siloxane coupling agent. Two parts of the composite siloxane coupling agent, 32 parts of carbon black N550, 16 parts of boron nitride nanosheets CY-HBN, and two parts of the aramid nanofibers prepared in Example 1 are placed in a kneader and kneaded at 45°C and 30 r / min for 15 min. The finished filler is obtained; Step 2, 70 parts of EPDM rubber and 30 parts of natural rubber are placed in a mixer and plasticized at 30 r / min for 5 min. Then the finished filler prepared in Step 1 is added and the mixture is mixed at 70℃ for 10 min. Then 1.5 parts of antioxidant 4010NA, 0.5 parts of antioxidant 264 and 7.5 parts of paraffin oil are added and the mixture is mixed at 70℃ for 5 min. Then the rubber compound is placed in a two-roll mill, thinly passed 5 times, and then sheeted at 135℃ to obtain the primary compound.

[0088] Step 2: The primary rubber compound is placed in an internal mixer and plasticized at 30 r / min for 5 min. 6 parts zinc stearate, 1.0 part sulfur, 0.36 parts accelerator ZDEC, 0.12 parts accelerator TETD, 0.12 parts accelerator CBS, and 1.2 parts alkylphenol disulfide are added to the compound. The mixture is then milled at 120℃ for 3 min and left to stand at room temperature for 24 h to obtain the finished rubber compound. The obtained finished rubber compound is then molded into a preform. The preform is then vulcanized at 170℃ for 302 s to obtain a high weather-resistant rubber balance block.

[0089] Performance testing:

[0090] 1. Vulcanization characteristics: Tested according to GB / T 9869-2014.

[0091] 2. Tensile property test: The test shall be conducted in accordance with GB / T 528-2009, with a tensile rate of 500 mm / min.

[0092] 3. Ozone aging cracking resistance: Tested according to GB / T 7762-2014, Static tensile test for ozone cracking resistance of vulcanized rubber or thermoplastic rubber. Test conditions: ozone concentration 200±20 PPHM, temperature 23±2℃ / 60±5RH%. Timing starts from the moment the sample is placed in the chamber and the chamber door is closed. The test lasts for 48 hours. Every 6.0 hours, the sample is removed for brief observation, and the initial cracking condition is recorded before returning it to the chamber to continue the test. After stretching by 20%, the surface cracking of the sample is observed using a 5x magnifying glass: Grade 0: No cracking, no cracks observed even under magnification. Grade 1: Slight cracking, only tiny cracks visible under magnification. Grade 2: Significant cracking, cracks clearly visible to the naked eye. Grade 3: Severe cracking, large and dense cracks. Grade 4: Very severe cracking, which may lead to sample breakage. Low-temperature brittleness test conditions: after being stored at -35℃ for 24 hours, the sample was stretched by 20%, and the surface cracking was observed with a 5x magnifying glass.

[0093] 4. The resistance to damp heat aging was tested in accordance with GB / T 15905-1995.

[0094] Table 1: Test parameters of mechanical properties of rubber compositions in Examples 1-6 and Comparative Examples 1-10

[0095] <![CDATA[Scorch time t c10 > <![CDATA[Optimum cure time t c90 > ML / N•m MH / N•m Tensile strength (MPa) Elongation at break % Example 1 1:29 4:35 1.09 5.21 9.68 738.90 Example 2 1:40 5:18 1.16 5.27 9.25 705.38 Example 3 1:58 5:09 1.13 5.16 8.58 769.05 Example 4 1:36 4:54 1.11 5.22 9.41 708.98 Example 5 1:21 4:09 1.07 5.18 9.83 680.18 Example 6 1:44 5:02 1.12 5.23 9.98 667.58 Comparative Example 1 1:25 4:02 1.39 6.07 8.43 651.15 Comparative Example 2 2:04 5:21 1.51 6.32 7.87 659.48 Comparative Example 3 1:59 5:15 1.43 6.15 8.06 671.63 Comparative Example 4 1:46 5:24 1.32 5.94 8.35 683.78 Comparative Example 5 1:38 5:06 1.27 5.79 8.41 689.85 Comparative Example 6 1:35 5:01 1.19 5.52 8.57 680.18 Comparative Example 7 1:25 4:32 1.01 4.98 7.40 794.03 Comparative Example 8 1:30 4:38 1.05 5.09 8.36 747.90 Comparative Example 9 1:32 4:35 1.07 5.15 9.11 766.35 Comparative Example 10 1:42 5:02 1.23 5.48 8.84 672.53

[0096] Table 2: Test parameters for the mechanical aging resistance of the rubber compositions in Examples 1-6 and Comparative Examples 1-10

[0097] Ozone aging resistance Resistance to damp heat aging Low temperature brittleness / grade Example 1 48h: Level 0 No blooming, no cracking Grade 0, no cracks Example 2 48h: Level 0 No blooming, no cracking Grade 0, no cracks Example 3 48h: Level 0 No blooming, no cracking Grade 0, no cracks Example 4 48h: Level 0 No blooming, no cracking Grade 0, no cracks Example 5 48h: Level 0 No blooming, no cracking Grade 0, no cracks Example 6 48h: Level 0 No blooming, no cracking Grade 0, no cracks Comparative Example 1 48h: Level 1 No blooming, no cracking Grade 0, no cracks Comparative Example 2 48h: Level 2 It has frost-like coating but no cracks. Grade 1, slight cracking Comparative Example 3 48h: Level 2 It has frost-like coating but no cracks. Grade 1, slight cracking Comparative Example 4 48h: Level 1 No blooming, no cracking Grade 0, no cracks Comparative Example 5 48h: Level 1 No blooming, no cracking Grade 0, no cracks Comparative Example 6 48h: Level 1 No blooming, no cracking Grade 0, no cracks Comparative Example 7 48h: Level 2 No blooming, no cracking Grade 1, slight cracking Comparative Example 8 48h: Level 1 No blooming, no cracking Grade 1, slight cracking Comparative Example 9 48h: Level 2 No blooming, no cracking Grade 0, no cracks Comparative Example 10 48h: Level 1 No blooming, no cracking Grade 1, slight cracking

[0098] Based on Example 1 and Comparative Examples 1-6, and in conjunction with Table 1-2, it can be seen that by surface modification of the filler with a composite siloxane coupling agent, the resulting filler exhibits little polarity difference compared to EPDM and NR. The filler surface-modified with the composite siloxane coupling agent can be uniformly dispersed within the EPDM / NR matrix, effectively improving the processing performance, mechanical properties, and ozone aging crack resistance of the rubber balance block. The rubber balance block prepared in Example 1 did not crack (grade 0) after 48 hours of aging test at an ozone concentration of 200 PPHM.

[0099] As can be seen from Example 1 and Comparative Examples 7-9 and Table 1-2, surface treatment of fillers composed of carbon black, flake nanofillers, and aramid nanofibers with composite siloxane coupling agents can make the filler system uniformly dispersed inside the EPDM / NR matrix, thereby improving the processing performance, mechanical properties, ozone aging crack resistance, air tightness, and heat stability of rubber balance blocks, and improving the processing performance, ozone aging resistance, mechanical properties, and low-temperature flexibility of existing EPDM / NR rubber compositions.

[0100] Based on Example 1 and Comparative Example 10, and in conjunction with Tables 1-2, it can be seen that nanoscale sheet-like nanofillers and aramid nanofibers are prone to agglomeration and cannot be adapted to the one-step blending method for producing rubber balance blocks. They need to be surface-treated separately before use to improve the dispersion uniformity of sheet-like nanofillers and aramid nanofibers in the EPDM / NR matrix, thereby improving the processing performance, mechanical properties, and ozone aging crack resistance of the rubber balance blocks.

[0101] Based on Examples 1 and 2-6 and Table 1-2, it can be seen that the accelerator composition prepared by compounding accelerator ZDEC, accelerator TETD, and accelerator CBS in a mass ratio of (6-8):(2-4):(2-4) can ensure the mechanical properties and ozone aging crack resistance of the rubber balance block.

[0102] In summary, the rubber balance block of this invention has good mechanical properties and resistance to ozone aging and cracking. It does not crack after 48 hours of aging test at an ozone concentration of 200 PPHM, thus expanding its application range.

[0103] It should be noted that this specific embodiment is merely an explanation of the technical solution of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A highly weatherable rubber balance weight, characterized by: The raw materials including the following weight parts are made: 65-75 parts of ethylene propylene diene rubber EPDM, 25-35 parts of natural rubber NR, 5.0-6.5 parts of zinc stearate, 1.5-2.5 parts of antioxidant, 0.8-1.0 parts of sulfur, 0.3-0.9 parts of accelerator, 1.0-1.5 parts of alkyl phenol disulfide, 5-10 parts of plasticizer, 40-60 parts of filler, 2-4 parts of composite siloxane coupling agent; the filler is obtained after surface modification treatment by the composite siloxane coupling agent; the composite siloxane coupling agent includes 3-butene triethoxysilane, bicyclo[2.2.1]-5-heptene-2-yl triethoxysilane, bis-[3-(triethoxysil)propyl]-tetrasulfide, and is compounded in a mass ratio of (25-35):(65-75):(80-120).

2. The high weatherable rubber balance weight of claim 1, wherein: The filler is carbon black, sheet-shaped nanofiller, aramid nanofiber, and is compounded in a mass ratio of (60-85):(20-35):(3-6).

3. The high weatherable rubber balance weight of claim 2, wherein: The sheet-shaped nanofiller is at least one of hydroxyl-modified graphene, boron nitride nanosheet, and molybdenum disulfide nanosheet.

4. The high weatherable rubber balance weight of claim 3, wherein: The surface modification treatment method of the carbon black is as follows: the carbon black and the composite siloxane coupling agent are weighed in a mass ratio of 10:(0.5-1) and then placed in a kneader, and then kneaded at 40-60°C for 15-30 min; the surface modification treatment method of the sheet-shaped nanofiller is as follows: the boron nitride nanosheet is dispersed in an organic solvent to form a suspension, and then the composite siloxane coupling agent is added dropwise to the suspension at a rotation speed of 100-400 rpm, the mass ratio of the composite siloxane coupling agent to the boron nitride nanosheet being (0.5-1):10, and then ultrasonic dispersion treatment is performed for 15-60 min after the dropwise addition is completed, and then the wet material obtained after pressure reduction filtration is vacuum dried; the surface modification treatment method of the aramid nanofiber is as follows: the aramid nanofiber is dispersed in an organic solvent to form a suspension, and then diisocyanate is added dropwise to the suspension at a rotation speed of 100-400 rpm for NCO surface modification treatment, the mass ratio of the diisocyanate to the aramid nanofiber being (0.5-2):100, and then the composite siloxane coupling agent is added dropwise to the suspension at a rotation speed of 100-400 rpm, and then ultrasonic dispersion treatment is performed for 15-60 min after the dropwise addition is completed, and then the wet material obtained after pressure reduction filtration is vacuum dried.

5. The high weatherable rubber balance weight of claim 1, wherein: The accelerator is at least one of accelerators ZDEC, ZDMC, TETD, TMTD, CBS, and NOBS.

6. The high weatherable rubber balance weight of claim 5, wherein: The accelerator is accelerator ZDEC, TETD, CBS, and is compounded in a mass ratio of (6-8):(2-4):(2-4).

7. The high weatherable rubber balance weight of claim 1, wherein: The antioxidant is at least one of antioxidants 4010NA, IPPD, AW, 264, and DNP.

8. The high weatherable rubber balance weight of claim 7, wherein: The antioxidant is antioxidant 4010NA and antioxidant 264, and is compounded in a mass ratio of (6-8):(2-4).

9. The high weatherable rubber balance weight of claim 1, wherein: The plasticizer is at least one of paraffin oil, naphthenic oil, and white oil.

10. A method of producing the highly weatherable rubber balance weight of any one of claims 1-9, characterized by: The method includes the following steps: Step one, surface modification treatment of the filler by the composite siloxane coupling agent to obtain the finished product filler; Step two, accurately metered ternary ethylene propylene rubber, natural rubber is plasticated at 30±5r / min for 3-5min, then accurately metered finished product filler, antioxidant, plasticizer is mixed and milled at 70±5℃ for 10-15min, then thin pass 3-5 times and open mill to get primary mixed rubber; Step three, zinc stearate, sulfur, accelerator, alkyl phenol disulfide is added to the mixed rubber, and is open-milled at 100-120℃ for 3-5min, and is stopped at room temperature for 18-24h to obtain a finished product mixed rubber. The finished product mixed rubber is molded into a preform by molding, and the preform is subjected to vulcanization treatment at a temperature of 170-180℃ for 4-6min to obtain a high-weather-resistance rubber balance block.