Low-temperature-resistant and oil-resistant damping rubber composite material for outdoor engineering and preparation method thereof

Abstract

The present application relates to a kind of low-temperature-resistant oil-resistant damping rubber composite material for outdoor engineering and its preparation method, belong to damping rubber modification technical field.The low-temperature-resistant oil-resistant damping rubber composite material for outdoor engineering described in the present application is prepared by high-vinyl polybutadiene rubber, butyl rubber, flocculation butyl nitrile rubber / oxidized carbon nanotube composite raw rubber and auxiliary mixing co-vulcanization.The vinyl content of high-vinyl polybutadiene rubber is 83-85%, Mn is 430-470, and the relative molecular mass distribution index is 2.0-2.5.The low-temperature-resistant oil-resistant damping rubber composite material for outdoor engineering described in the present application has a wider damping temperature range, excellent low-temperature damping performance, mechanical properties and oil resistance;Meanwhile, a simple and convenient preparation method is provided.

Description

Technical Field

[0001] This invention relates to a low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering and its preparation method, belonging to the field of damping rubber modification technology. Background Technology

[0002] Damping materials require high internal friction, i.e., a large tanδ. An ideal damping material should have large internal friction across the entire operating temperature range, meaning its tanδ-T curve should change smoothly, and the envelope area between the material and the temperature coordinates should be as large as possible.

[0003] Commonly used maximum loss factor (tanδ) max The damping characteristics of polymer materials are characterized by parameters such as glass transition temperature (Tg) and the half-maximum width at half maximum (FWHM) of the damping peak (Δ0.3, the temperature range corresponding to tanδ not less than 0.3). Within the frequency range and temperature range of product use, a larger tanδ indicates better damping performance; Tg is the temperature corresponding to the highest peak of the tanδ-temperature curve, representing the optimal operating temperature of the material; a wider Δ0.3 indicates a wider effective damping temperature range for the material.

[0004] Damping rubber materials have a wide range of applications, such as in the automotive, aerospace, bridge, and transportation industries, primarily controlling vibration and noise hazards through their damping effect. Rubber is a viscoelastic material, and its damping is related to dynamic mechanical relaxation. The fundamental reason for the damping effect of rubber materials is due to hysteresis and internal mechanical friction. High-damping materials require a relatively wide damping temperature range; when tanδ > 0.3, the polymer must have a temperature range of at least 60-80℃.

[0005] Currently, most damping rubber materials have low Tg in their main body material, and their effective damping temperature range is mostly in the low-temperature region with a narrow temperature range (20-30℃), which cannot meet the damping performance requirements of rubber products at room temperature.

[0006] Molybdenum-based high-vinyl polybutadiene rubber (HVBR) has abundant vinyl side groups (vinyl content above 80%), which increases the relaxation resistance of the chain segments, resulting in greater internal friction and better damping and vibration reduction performance. Furthermore, its glass transition temperature is -24℃, and its effective damping temperature range is closer to room temperature compared to other rubber damping materials. This rubber material also exhibits excellent aging resistance, showing potential to become an ideal rubber damping material. However, its effective damping temperature range needs to be further expanded.

[0007] Butyl rubber (IIR) exhibits excellent damping properties due to the large number of methyl groups in its molecular chains, resulting in significant internal friction between the chains. This increased resistance during chain relaxation leads to greater internal friction. Although IIR contains many methyl groups, its helical molecular configuration, with each pair of methyl groups offset from one another at an angle, results in a relatively flexible chain with good elasticity and a low glass transition temperature (-69℃). It demonstrates good low-temperature damping performance, with a damping temperature range of -70℃ to 20℃, but poor high-temperature damping performance.

[0008] Patent 201710295220.5 discloses a vibration-damping rubber composite material and its preparation method, belonging to the field of rubber. Its characteristic is that the composition by weight is: 10-30 parts modified high-vinyl polybutadiene rubber and 90-70 parts modified ethylene propylene diene monomer (EPDM) rubber. The process includes the following steps: ball milling carbon nanotubes using a ball mill, adding 3-5 drops of anhydrous ethanol as a grinding aid during the ball milling process to obtain short-cut carbon nanotubes; adding the short-cut carbon nanotubes to the high-vinyl polybutadiene rubber in a mixer and mixing; adding C5 petroleum resin to EPDM in a mixer and mixing; and co-curing the modified HVPBR and modified EPDM rubber, along with processing aids, in a mixer for 10-15 minutes. The resulting composite material exhibits a wider damping temperature range and good mechanical properties after blending.

[0009] Patent 201810926758.6 discloses a high-damping blend with an effective damping temperature range greater than 65℃ and its preparation method. The wide-temperature-range high-damping blend comprises the following components and weight fractions: 50-100 parts of ionomer of multifunctional high-vinyl polybutadiene rubber and 0-50 parts of ethylene-vinyl acetate rubber. First, the multifunctional high-vinyl polybutadiene rubber is reacted with a metal alkali and hydroxide to generate an ionomer. Then, the ionomer of the multifunctional high-vinyl polybutadiene rubber and the ethylene-vinyl acetate rubber are successively placed in a two-roll mill or internal mixer and mechanically blended for 5-30 minutes to obtain the high-damping blend with an effective damping temperature range greater than 65℃. This patent can effectively broaden the effective damping temperature range and significantly improve damping performance.

[0010] Although the aforementioned patents have achieved certain beneficial effects, the improvements are limited, or they cannot simultaneously improve the overall performance of the product, and further improvements are still needed. Summary of the Invention

[0011] The purpose of this invention is to provide a low-temperature and oil-resistant damping rubber composite material for outdoor engineering, which has a wide damping temperature range and excellent low-temperature damping performance, mechanical properties and oil resistance; at the same time, this invention provides a simple and convenient preparation method.

[0012] The low-temperature and oil-resistant damping rubber composite material for outdoor engineering described in this invention is prepared by co-curing and mixing high-vinyl polybutadiene rubber, butyl rubber, flocculated nitrile rubber / carbon oxide nanotube composite raw rubber and additives.

[0013] Preferably, the high-vinyl polybutadiene rubber has a vinyl content of 83-85%, a Mn content of 430,000-470,000, and a relative molecular mass distribution index of 2.0-2.5.

[0014] Preferably, the butyl rubber has an Mn of 200,000-250,000, an Mw of 420,000-460,000, and a molecular weight distribution of 2-2.1.

[0015] Preferably, the acrylonitrile content of the nitrile rubber is 25-30%, Mn is 50,000-70,000, Mw is 180,000-220,000, and the molecular weight distribution is 3.1-3.3.

[0016] The aforementioned low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering preferably comprises the following raw materials in parts by weight:

[0017] HVPBR 63.0-67.0 parts, flocculated nitrile butadiene rubber + carbon oxide nanotube composite raw rubber 24.0-26.0 parts, butyl rubber 9.0-11.0 parts, stearic acid 0.5-2.0 parts, sulfur 1.0-3.0 parts, zinc oxide 3.0-6.0 parts, accelerator TMTD 1.0-3.0 parts, accelerator TBBS 0.5-2.0 parts, carbon black 35-55 parts.

[0018] The preparation method of the low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering includes the following steps:

[0019] (1) Preparation of flocculated nitrile butadiene rubber + carbon oxide nanotube composite raw rubber:

[0020] The positive flocculation method is used, in which latex is added to the coagulant solution.

[0021] 1) Add 1000mL of deionized water to the coagulation vessel and preheat to 60℃. Then add 300mL of 5% carbon oxide nanotube emulsion and turn on the stirrer to stir at 400r / min to fully disperse the carbon oxide nanotubes in the water. Add antioxidant 4010NA to the nitrile latex and stir evenly. Preheat in a 60℃ water bath for 30min.

[0022] 2) Using a beaker, add 55 mL of 10% flocculant CaCl2 and 50 mL of PEO-b-PMMA-b-PS block copolymer DMF solution (2 mg / mL) to a coagulation vessel containing carbon oxide nanotubes. After dispersing evenly, slowly add 400 mL of 25% acrylonitrile latex (acrylonitrile content 29%) to the coagulation vessel. Control the glue addition speed according to the size of the flocculent particles to avoid glue encapsulation. Gradually separate the water and glue. Stop adding glue after the water becomes clear to obtain a flocculent acrylonitrile rubber + carbon oxide nanotube composite with a certain moisture content.

[0023] 3) Take the water-containing flocculated nitrile rubber + carbon oxide nanotube composite out of the flocculation vessel, wash it twice with 5-8 times its weight of deionized water to remove the unflocculated latex, drain the water, spread it flat on an enamel plate, put it in a drying oven, and dry it at 100℃ for 2-4 hours to obtain the dry flocculated nitrile rubber / carbon oxide nanotube composite.

[0024] (2) Preparation of rubber composite materials:

[0025] The high-vinyl polybutadiene rubber, butyl rubber, flocculated nitrile rubber / carbon oxide nanotube composite raw rubber and additives are co-mixed in an internal mixer and then co-vulcanized.

[0026] Nitrile butadiene rubber (NBR) possesses highly polar side groups, exhibiting excellent damping properties, as well as superior oil resistance, heat resistance, and abrasion resistance. Extremely high acrylonitrile NBR (acrylonitrile content above 43%) is highly polar and has poor compatibility with butyl rubber. Medium-high acrylonitrile NBR has an acrylonitrile content of 31-35%; medium acrylonitrile NBR has an acrylonitrile content of 25-30%; and low acrylonitrile NBR has an acrylonitrile content below 24%. When the acrylonitrile content is low, oil resistance is poor. An acrylonitrile content of around 30% is selected, specifically 29%. NBR with an acrylonitrile content of 29% exhibits good oil resistance, good mechanical properties, and good compatibility with butyl rubber.

[0027] The amphiphilic block copolymer PEO-b-PMMA-b-PS contains both hydrophilic and hydrophobic portions, with the hydrophilic portion contributing to its excellent hydrophilicity. PEO is highly soluble in both water and most organic solvents.

[0028] The carbon oxide nanotubes have carboxyl groups on them, and the hydroxyl groups at the PEO ends enable the carbon oxide nanotubes to have good compatibility with the PEO segments in the block copolymer PEO-b-PMMA-b-PS, which can effectively disperse the carbon oxide nanotubes in PEO-b-PMMA-b-PS.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] This invention utilizes butyl rubber (IIR), which has good heat resistance, aging resistance, and weather resistance. By using IIR and flocculated nitrile butadiene rubber / carbon oxide nanotube composite raw rubber, the problems of poor processing performance and narrow effective damping temperature range of HVPBR are improved. The effective damping temperature range (tanδ≥0.3) reaches 78℃, resulting in a rubber damping composite material for outdoor engineering with good low-temperature damping performance, significantly improved mechanical properties, and significantly improved oil resistance. Detailed Implementation

[0031] The present invention will now be described in detail through specific embodiments, but the present invention is not limited to these embodiments.

[0032] Unless otherwise specified, all raw materials are commercially available.

[0033] In the examples and comparative examples, the amounts of raw materials used are all parts by mass.

[0034] Table 1 Formulation of Examples

[0035]

[0036] Table 2 Formulations of Examples

[0037]

[0038] Table 3 Comparative Formulas

[0039]

[0040]

[0041] Table 4 Damping performance of the embodiments

[0042]

[0043] Table 5 Physical properties of the embodiments

[0044]

[0045] Table 6 Damping performance of comparative examples

[0046]

[0047] Table 7 Physical properties of comparative examples

[0048]

[0049] When the vinyl content in HVPPBR exceeds 85%, its processing performance is poor. This invention selects HVPPBR with a vinyl content of 83-85%, but even with 83-85% HVPPBR processed and plasticized alone, poor processing performance remains, with long internal mixing and plasticizing times exceeding 40 minutes without plasticization. Therefore, this invention adds IIR and flocculated NBR + carbon oxide nanotubes to HVPPBR to improve its processing performance, shortening the internal mixing and plasticizing time of the rubber composite to 18-25 minutes.

[0050] As can be seen from Examples 1-4 and Comparative Examples 1-2, when the HVPBR dosage is 62 parts, tanδ max The effective damping temperature range is relatively narrow; when the HVPBR dosage is 69 parts, tanδ max While the damping performance is relatively high, the effective damping temperature range is narrow, and the processability of the rubber composite material is poor. When the HVPBR content is 64-67 parts, the rubber composite material exhibits better damping performance, with an effective damping temperature range (tanδ≥0.3) reaching 75℃, along with good physical properties and processability. Therefore, the recommended HVPBR content is 64-67 parts.

[0051] As can be seen from Examples 5-6 and Comparative Examples 3-4, when the amount of flocculated NBR + carbon dioxide nanotubes is 20 parts, the tanδ of the rubber composite material... max The oil resistance is relatively high, but the oil resistance is poor, and the effective damping temperature range is narrow. When the content of flocculated NBR + carbon oxide nanotubes is 28 parts, the rubber composite material has good oil resistance, but poor low-temperature damping. When the content of flocculated NBR + carbon oxide nanotubes is 24-26 parts, the rubber composite material has good oil resistance. Therefore, the content of flocculated NBR + carbon oxide nanotubes is determined to be 24-26 parts.

[0052] As can be seen from Examples 7-8 and Comparative Examples 5-6, the low-temperature damping performance is poor when the IIR dosage is 7 parts; the low-temperature damping performance is better when the IIR dosage is 12 parts, but the effective damping temperature range is narrow. The low-temperature damping performance of the rubber composite material is better when the IIR dosage is 9-11 parts. Therefore, the IIR dosage was determined to be 9-11 parts.

[0053] As can be seen from Example 2 and Comparative Example 7, the HVPBR / IIR / flocculated NBR+carbon black composite material exhibits better mechanical properties than the HVPBR / IIR / flocculated NBR+carbon oxide nanotube composite material, thus meeting the requirements for outdoor engineering. Therefore, the rubber composite material is determined to be the HVPBR / IIR / flocculated NBR+carbon oxide nanotube composite material.

Claims

1. A low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering, characterized in that: It is prepared by compounding and co-curing high vinyl polybutadiene rubber, butyl rubber, flocculated nitrile rubber / carbon oxide nanotube composite raw rubber and additives; The vinyl content of high-vinyl polybutadiene rubber is 83-85%, Mn is 430,000-470,000, and the relative molecular mass distribution index is 2.0-2.5; the Mn of butyl rubber is 200,000-250,000, Mw is 420,000-460,000, and the molecular weight distribution is 2-2.

1. The acrylonitrile content of nitrile rubber is 25-30%, Mn is 50,000-70,000, Mw is 180,000-220,000, and the molecular weight distribution is 3.1-3.

3. The preparation method of flocculated nitrile rubber / carbon oxide nanotube composite raw rubber is as follows: the flocculant and the DMF solution of PEO-b-PMMA-b-PS block copolymer are added to the coagulation vessel containing carbon oxide nanotubes, nitrile rubber latex is added, and then the mixture is washed and dried to obtain the composite raw rubber. The composite material comprises the following parts by weight of raw materials: HVPBR 63.0-67.0 parts, flocculated nitrile butadiene rubber + carbon oxide nanotube composite raw rubber 24.0-26.0 parts, butyl rubber 9.0-11.0 parts, stearic acid 0.5-2.0 parts, sulfur 1.0-3.0 parts, zinc oxide 3.0-6.0 parts, accelerator TMTD 1.0-3.0 parts, accelerator TBBS 0.5-2.0 parts, carbon black 35-55 parts.

2. The method for preparing the low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering as described in claim 1, characterized in that, Includes the following steps: (1) Preparation of flocculated nitrile rubber / carbon oxide nanotube composite raw rubber: 1) After preheating with deionized water in the coagulation vessel, add carbon dioxide nanotube emulsion and start stirring; add antioxidant to nitrile latex and stir evenly, then preheat in a water bath; 2) Add the flocculant CaCl2 and the DMF solution of PEO-b-PMMA-b-PS block copolymer to the coagulation vessel containing carbon oxide nanotubes in a beaker and disperse them. Then add the nitrile rubber latex containing antioxidant to the coagulation vessel and gradually separate the water and glue. Stop adding glue after the water is clear to obtain a flocculated nitrile rubber / carbon oxide nanotube composite with a certain moisture content. 3) Take the water-containing flocculated nitrile rubber / carbon oxide nanotube composite out of the flocculation kettle, wash it with deionized water, drain the water, spread it flat on an enamel plate, and dry it in a drying oven to obtain the raw rubber of the flocculated nitrile rubber / carbon oxide nanotube composite. (2) Preparation of rubber composite materials: The high-vinyl polybutadiene rubber, butyl rubber, flocculated nitrile rubber / carbon oxide nanotube composite raw rubber and additives are co-mixed in an internal mixer and then co-vulcanized. In step (1), the amount of 10wt% flocculant CaCl2 added is 55mL; the concentration of the DMF solution of PEO-b-PMMA-b-PS block copolymer is 2mg / mL, and the amount added is 50mL; the mass fraction of nitrile latex is 25%, and the amount added is 400mL. In step (1), dry at 100℃ for 2-4 hours.

3. The method for preparing the low-temperature resistant and oil-resistant damping rubber composite material for outdoor engineering according to claim 2, characterized in that: In step (2), blend for 10-15 minutes.

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