A bio-based high-damping rubber material and preparation method thereof

Abstract

The present invention discloses a bio-based high-damping rubber material and a preparation method thereof. The material comprises 100 parts of raw rubber; 3-10 parts of zinc oxide; 1-3 parts of stearic acid; 10-60 parts of a reinforcing filler; 2-20 parts of a plasticizer; 4-10 parts of an antioxidant; 2-15 parts of a damping material; and 1.5-6 parts of a vulcanization system. The rubber is itaconate rubber or a mixture of itaconate rubber and natural rubber, and the damping material includes polynorbornene rubber and a damping additive A. The rubber material of the present invention solves the problem that conventional damping rubbers cannot balance damping performance and fatigue performance, and suffer from unstable damping performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of rubber materials, and in particular relates to a bio-based high-damping rubber material and a preparation method thereof. Background Art

[0002] Bio-based itaconate rubber is a new type of rubber material produced through low-temperature emulsion polymerization using itaconate, a green and environmentally friendly biomass, as the primary monomer. It is a world-first in bio-based synthetic rubber. Compared to natural rubber, itaconate rubber exhibits superior damping and flexural properties, particularly flexural properties. When itaconate rubber is used to partially replace natural rubber as the primary raw rubber, to improve the damping properties of the itaconate rubber and / or natural rubber, it is often combined with a high-damping raw rubber (such as chloroprene rubber, nitrile rubber, etc.) or with a high-damping material (such as AO-80, antioxidant 1010, or a damping resin). However, since itaconate rubber and natural rubber are non-polar raw rubbers, their compatibility with polar rubbers with high damping properties (such as chloroprene rubber, nitrile rubber, etc.) is poor, resulting in poor mechanical properties that fail to meet product requirements. Summary of the Invention

[0003] In order to overcome the problems in the prior art, the present invention provides a bio-based high-damping rubber material and a preparation method thereof. The prepared damping material has good compatibility with raw rubber and will not have precipitation problems during actual use. It solves the problem of instability of damping performance of traditional damping rubber materials and products, and at the same time solves the difficult problem of traditional damping materials that cannot take into account both damping performance and fatigue performance.

[0004] In order to solve the above technical problems, the technical solutions proposed by the present invention are as follows:

[0005] The present invention provides a bio-based high-damping rubber material, comprising the following raw materials in parts by mass: raw rubber: 100 parts; zinc oxide: 3-10 parts; stearic acid: 1-3 parts; reinforcing filler: 10-60 parts; plasticizer: 2-20 parts; antioxidant: 4-10 parts; damping material: 2-15 parts; and vulcanization system: 1.5-6 parts. The rubber is itaconate rubber, or a mixture of itaconate rubber and natural rubber, and the damping material comprises polynorbornene rubber.

[0006] The present invention uses itaconate rubber and natural rubber as raw rubbers. Compared to natural rubber, itaconate rubber has better damping and flexural properties, especially flexural properties. The combination of the two significantly improves fatigue performance while ensuring damping performance. Polynorbornene rubber (PNR) with high damping properties is also added. It has both cis and trans structures, which can avoid crystallization, has a glass transition temperature of 35-37°C, and has high shock absorption and damping properties. The loss factor can be as high as 3 or even higher, and most vibration energy can be converted into heat energy. Furthermore, its molecular chain contains C=C double bonds, which can chemically react with the C=C double bonds in the itaconate / natural rubber molecular chain. Thus, the polynorbornene rubber and itaconate / natural rubber are organically combined through the cross-linking action of the vulcanizing agent, improving the compatibility between the two and significantly improving the damping performance of the itaconate / natural rubber.

[0007] As an optional embodiment, in the bio-based high-damping rubber material provided by the present invention, the damping material further includes a damping aid A, and the structural formula of the damping aid A is shown in the following formula (1):

[0008]

[0009] In order to further improve the damping performance of itaconate rubber and / or natural rubber, the present invention also adds a damping auxiliary agent A, whose molecular structure contains a large number of benzene ring structures, which can increase the steric hindrance effect and further significantly improve the damping performance of the rubber material; in addition, the carboxyl group in the molecular structure of the new damping auxiliary agent can react chemically or form hydrogen bonds with the hydroxyl group on the surface of the filler or the epoxy group in the molecular structure of the plasticizer under certain conditions, forming chemical and / or physical bonding bonds; the amino group in its molecular structure can react chemically with the double bond in the rubber molecular chain under high temperature and condensation agent conditions, thereby organically combining the rubber molecular chain and the filler / plasticizer, fundamentally solving the problem of damping agent precipitation.

[0010] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the itaconate rubber is selected from one or more of binary itaconate rubber and ternary itaconate rubber; the natural rubber is selected from one or more of smoked sheet rubber, constant viscosity rubber and full latex.

[0011] Furthermore, the itaconate rubber is preferably ternary itaconate rubber; and the natural rubber is preferably smoked sheet rubber.

[0012] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the polynorbornene rubber in the damping material is 2-12 parts, and the damping aid A is 1-10 parts.

[0013] As an optional embodiment, in the bio-based high-damping rubber material provided by the present invention, the damping aid A is obtained by catalytic reaction of 5-amino-2,4,6-triiodoisophthalic acid and triarylimidazole.

[0014] As an optional embodiment, in the bio-based high-damping rubber material provided by the present invention, the synthesis process of the damping additive A is as follows: 5-amino-2,4,6-triiodoisophthalic acid and triarylimidazole are placed in a reaction vessel, cuprous iodide and ligand L-proline are added, and the reaction is stirred in a solvent at a temperature of 60-80°C under a nitrogen atmosphere for 12-48 hours, and then filtered to remove the supernatant, concentrate the solvent, and vacuum dry to obtain the damping additive A.

[0015] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the molar ratio of 5-amino-2,4,6-triiodoisophthalic acid to triarylimidazole is (1-1.1): (3.1-4).

[0016] In the present invention, the ratio of 5-amino-2,4,6-triiodoisophthalic acid and triaryl imidazole is controlled to be (1-1.1): (3.1-4). If it exceeds this range, small molecular substances may remain in the prepared damping additive A, affecting the damping effect.

[0017] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the solvent is selected from one of N,N-dimethylformamide, N,N-dimethylacetamide or dimethyl sulfoxide.

[0018] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the reinforcing filler is selected from one or more of bio-based carbon black, rice husk ash white carbon black, bio-based calcium carbonate, white carbon black, kaolin, qiangwei powder and montmorillonite.

[0019] Further, bio-based carbon black, rice husk ash white carbon black and bio-based calcium carbonate are preferred.

[0020] The present invention uses bio-based carbon black, rice husk ash white carbon black, and bio-based calcium carbonate. The bio-based carbon black is prepared from three raw materials: methane, carbon dioxide, and vegetable oil. Compared with traditional carbon black, its carbon emissions are greatly reduced. The rice husk ash white carbon black is prepared from rice husk ash, a by-product of rice processing. The bio-based calcium carbonate is prepared from oyster shells and can replace up to 80% of the carbon black in rubber products, thereby reducing carbon emissions by 80%-90%.

[0021] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the plasticizer is selected from one or more of soybean oil, castor oil, epoxidized soybean oil, epoxy cardanol laurate, epoxy cardanol acetate, and epoxy castor oil.

[0022] Furthermore, it is preferably one or more of epoxidized soybean oil, epoxy cardanol laurate, epoxy cardanol acetate, and epoxy castor oil.

[0023] In the present invention, plant oil-based plasticizers are used to replace petroleum-based plasticizers (including cyclohexane oil, paraffin oil, aromatic oil, etc.). The plasticizing effect of plant oil-based plasticizers is basically equivalent to that of petroleum-based plasticizers, but they are derived from plants, are renewable resources, and meet environmental protection requirements.

[0024] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the antioxidant is selected from one or more of quinolines, p-phenylenediamines, protective waxes and ultraviolet absorbers.

[0025] Furthermore, antioxidants RD, 4020, microcrystalline wax and UV-531 are preferred.

[0026] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the vulcanization system includes a vulcanizing agent and an accelerator.

[0027] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the vulcanizing agent is selected from one or more of sulfur, insoluble sulfur and sulfur carriers; the accelerator is selected from one or more of thiazole accelerators, sulfenamide accelerators and thiuram accelerators.

[0028] Furthermore, the vulcanizing agent is preferably sulfur and insoluble sulfur. The accelerator is preferably thiazole or sulfenamide, such as accelerator DM and accelerator NOBS.

[0029] As an optional embodiment, in the bio-based high damping rubber material provided by the present invention, the zinc oxide is selected from one of direct zinc oxide and indirect zinc oxide.

[0030] Furthermore, indirect zinc oxide is preferred.

[0031] Based on the same technical concept, the present invention also provides a method for preparing the above-mentioned bio-based high-damping rubber material, comprising the following steps:

[0032] Add itaconate rubber and natural rubber into an internal mixer, mix at 50-70°C for 1-2 minutes, then add reinforcing filler and plasticizer, mix for 1-2 minutes, add zinc oxide, stearic acid, antioxidant and damping material, mix evenly, cool to below 70°C, add vulcanizer and accelerator, remove from the sheet and cool naturally to obtain rubber compound, and vulcanize the rubber compound after it is left to stand.

[0033] As an optional embodiment, in the preparation method provided by the present invention, the vulcanization temperature during the vulcanization process is 140° C.-160° C., the vulcanization pressure is 10-20 MPa, and the vulcanization time is 10-30 minutes.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] (1) The bio-based itaconate rubber of the present invention partially or completely replaces natural rubber, thereby simultaneously improving the damping and fatigue properties of the rubber, solving the technical problem of traditional rubbers that cannot achieve both damping and fatigue properties. Simultaneously, the use of PNR to replace polar damping rubber (such as nitrile rubber) can further significantly improve the mechanical properties, damping properties, and fatigue properties of the rubber, and solves the problem of poor compatibility between natural rubber / itaconate and polar damping rubber, further improving the performance and service life of the rubber.

[0036] (2) The present invention adopts damping agent A to replace the traditional polar damping agent (such as AO-80), which solves the technical problem that the traditional damping agent is easy to precipitate, resulting in unstable damping performance of the rubber and the product, and further improves the mechanical, damping and fatigue properties of the rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is the NMR spectrum of the damping aid A prepared in Example 1. DETAILED DESCRIPTION

[0039] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0040] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0041] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0042] Example

[0043] The preparation process of damping agent A is as follows:

[0044] 5-Amino-2,4,6-triiodoisophthalic acid (1-1.1 eq, relative molecular weight 558.84) and triarylimidazole (3.1-4 eq, relative molecular weight 296.4) were placed in a reaction vessel, followed by the addition of cuprous iodide (1.5-6.0 eq, relative molecular weight 190.5), the ligand L-proline (1.5-6.0 eq, relative molecular weight 115.1), and one of potassium carbonate, sodium carbonate, or cesium carbonate (6.0-12.0 eq, relative molecular weights 138.2, 106.0, and 325.8, respectively). N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), or dimethyl sulfoxide (DMSO) (300-1000 eq) were then added. After purging with nitrogen for 30 minutes, the reaction was stirred at 60-80°C under a nitrogen atmosphere for 12-48 hours. Filter, remove the clear liquid, concentrate the solvent and dry in vacuum.

[0045] The NMR spectrum of the prepared damping agent A is shown in the attached figure. Figure 1 shown.

[0046] The synthetic formula is as follows:

[0047]

[0048] The raw material components and composition ratio of the bio-based high-damping rubber material are as follows: raw rubber: 100 parts; zinc oxide: 3-10 parts; stearic acid: 1-3 parts; reinforcing filler: 10-60 parts; plasticizer: 2-20 parts; antioxidant: 4-10 parts; damping material: 2-15 parts; vulcanization system: 1.5-6 parts.

[0049] The rubber compound mixing and vulcanization process is as follows:

[0050] (1) Rubber mixing process

[0051] Add raw rubber (one or more of natural rubber and itaconate rubber) into an internal mixer, mix at 50-70°C for 1-2 minutes, then add reinforcing filler, mix for 1-2 minutes, add plasticizer, zinc oxide, stearic acid, antioxidant and damping material, mix well, cool to below 70°C, add vulcanizer and accelerator, remove from the sheet and cool naturally.

[0052] (2) Rubber vulcanization process

[0053] After the rubber mix is ​​left standing for 16 hours, the vulcanization temperature is controlled at 140°C-160°C, the vulcanization pressure is controlled at 10-20 MPa, and the vulcanization time is controlled at 10-30 minutes to produce a high-performance rubber material with high bio-based content, high damping and fatigue resistance.

[0054] The samples of Examples 1 to 6 and Comparative Examples 1 to 3 were prepared according to the above operation. The specific addition amounts of each Example and Comparative Example are as shown in Table 1 below:

[0055] Table 1 Formula table of embodiment and comparative example (mass parts)

[0056]

[0057]

[0058] The properties of the corresponding rubber materials and products of the above examples and comparative examples were tested, and the parameter results were shown in Table 2:

[0059] Table 2: Detection performance parameters

[0060]

[0061]

[0062] From the comparison of Comparative Example 1, Example 1 and Example 2, it can be seen that after the use of bio-based itaconate rubber, although the tensile strength and elongation at break of the rubber are slightly reduced, the loss factor and fatigue performance of the rubber are significantly improved, which solves the technical problem that the damping performance and fatigue performance of the traditional rubber cannot be taken into account at the same time; from the comparison of Comparative Example 2 and Example 3, it can be seen that after adding high-damping polynorbornene rubber (PNR) to the rubber, the damping performance of the rubber is greatly improved, and other properties remain basically the same; from the comparison of Comparative Example 3 and Example 4, it can be seen that when polar nitrile rubber is used in combination, due to the large difference in polarity between natural rubber / itaconate rubber and it, the compatibility of the two when used in combination is poor, and the mechanical properties of the rubber are poor. The mechanical properties, damping properties and fatigue properties of the rubber are all poor. When non-polar high-damping polybornene rubber (PNR) is used in combination, the mechanical properties, damping properties and fatigue properties of the rubber are all better than those of Comparative Example 3, which solves the problem that polar rubber can improve the damping properties of natural rubber / itaconate rubber but has an adverse effect on the mechanical properties and fatigue properties; from the comparison of Comparative Example 4 and Example 5, it can be seen that when damping aid A is used, the mechanical properties, damping properties and fatigue properties of the rubber are all better than those of damping aid AO-80 and the technical problem of easy precipitation of AO-80 is solved at the same time; from the comparison of Example 5 and Example 6, it can be seen that increasing the amount of damping aid A can further improve the damping properties of the rubber, and has basically no effect on the mechanical properties and fatigue properties.

[0063] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A bio-based high damping rubber material, characterized in that: The invention comprises the following raw materials in parts by weight: raw rubber: 100 parts; zinc oxide: 3-10 parts; Stearic acid: 1-3 parts; reinforcing filler: 10-60 parts; Plasticizer: 2-20 parts; Antiaging agent: 4-10 parts; Damping material: 2-22 parts; Vulcanization system: 1.5-6 parts; the rubber is itaconate rubber, or a mixture of itaconate rubber and natural rubber, and the damping material includes polynorbornene rubber; The damping material further includes a damping aid A, and the structural formula of the damping aid A is shown in the following formula (1): 。 2. The bio-based high damping rubber material according to claim 1, characterized in that: The itaconate rubber is selected from one or more of binary itaconate rubber and ternary itaconate rubber; the natural rubber is selected from one or more of smoked sheet rubber, constant viscosity rubber and full latex.

3. The bio-based high damping rubber material according to claim 1, characterized in that: The damping material contains 2-12 parts of polynorbornene rubber and 1-10 parts of damping aid A.

4. The bio-based high damping rubber material according to claim 1, characterized in that: The damping auxiliary agent A is obtained by catalytic reaction of 5-amino-2,4,6-triiodoisophthalic acid and triaryl imidazole.

5. The bio-based high damping rubber material according to claim 4, characterized in that: The synthesis process of the damping additive A is as follows: 5-amino-2,4,6-triiodoisophthalic acid and triaryl imidazole are placed in a reaction vessel, cuprous iodide and a ligand L-proline are added, and the mixture is stirred in a solvent under a nitrogen atmosphere at a temperature of 60-80° C. for a reaction of 12-48 hours, and then filtered to remove the supernatant, concentrate the solvent, and vacuum dry to obtain the damping additive A.

6. The bio-based high damping rubber material according to claim 4 or 5, characterized in that: The molar ratio of the 5-amino-2,4,6-triiodoisophthalic acid to the triaryl imidazole is (1-1.1): (3.1-4).

7. The bio-based high damping rubber material according to claim 1, characterized in that: The reinforcing filler is selected from one or more of bio-based carbon black, rice husk ash white carbon black, bio-based calcium carbonate, white carbon black, kaolin, Qiangwei powder and montmorillonite; the plasticizer is selected from one or more of soybean oil, castor oil, epoxidized soybean oil, epoxy cardanol laurate, epoxy cardanol acetate and epoxy castor oil; the antioxidant is selected from one or more of quinolines, p-phenylenediamines, protective waxes and ultraviolet absorbers; the vulcanization system includes a vulcanizing agent and an accelerator, the vulcanizing agent is selected from one or both of sulfur and a sulfur carrier; the accelerator is selected from one or more of thiazole accelerators, sulfenamide accelerators and thiuram accelerators.

8. The method for preparing a bio-based high damping rubber material according to any one of claims 1 to 7, characterized in that: The following steps are involved: Add itaconate rubber and natural rubber into an internal mixer, mix at 50-70°C for 1-2 minutes, then add reinforcing filler and plasticizer, mix for 1-2 minutes, add zinc oxide, stearic acid, antioxidant and damping material, mix evenly, cool to below 70°C, add vulcanizer and accelerator, remove from the sheet and cool naturally to obtain rubber compound, and vulcanize the rubber compound after it is left to stand.

9. The method for preparing a bio-based high damping rubber material according to claim 8, characterized in that: During the vulcanization process, the vulcanization temperature is 140°C-160°C, the vulcanization pressure is 10-20MPa, and the vulcanization time is 10-30 minutes.

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