JP4296972B2 - Anti-vibration rubber manufacturing method and anti-vibration rubber obtained thereby - Google Patents

Description

  The present invention relates to a method for producing a vibration-proof rubber and a vibration-proof rubber obtained thereby, and more specifically, a method for producing a vibration-proof rubber having a sea-island structure in which island phases are dispersed in a matrix rubber, and to be obtained thereby. The present invention relates to a vibration-proof rubber.

  In general, anti-vibration rubber interposed between two members constituting a vibration transmission system and anti-vibrating and connecting both members has been widely used in various fields. For example, in the automobile field, It has been used as an engine mount, body mount, member mount, suspension bush, and the like.

By the way, in the anti-vibration rubber used in the automobile field as described above, since it is used in a transmission system of a plurality of types of vibrations having different frequencies, the anti-vibration characteristics corresponding to each input vibration are usually provided. It is required to be effective. Specifically, in an anti-vibration rubber for automobiles, generally, when vibration in a relatively high frequency region of 100 Hz or more is input, low dynamic spring characteristics are required, and a relatively low frequency of 30 Hz or less. When a region vibration is input, a high damping characteristic is required. Here, the low dynamic spring characteristic means that the value of the dynamic magnification (Kd ₁₀₀ / Ks), which is the ratio of the dynamic spring constant (Kd ₁₀₀ ) and the static spring constant (Ks) at ₁₀₀ Hz, is small. In addition, the high damping characteristic means that the loss coefficient (tan δ) value at the time of vibration input at 15 Hz is large (hereinafter the same).

  In general, the mechanism of the development of spring characteristics in anti-vibration rubber is based on bonds / restraints or entanglements between polymer molecules constituting anti-vibration rubber, or bonds / restraints between polymer molecules and reinforcing agents. The expression mechanism of the damping characteristic is based on friction between polymer molecules or between a polymer molecule and a reinforcing agent. Therefore, if the damping characteristics of the anti-vibration rubber are increased, the spring characteristics of the anti-vibration rubber will increase accordingly. Conversely, if the low dynamic spring characteristics of the anti-vibration rubber are realized, the damping of the anti-vibration rubber will be accompanied accordingly. There is a conflicting problem that the characteristics deteriorate. As described above, since the low dynamic spring characteristics and the high damping characteristics are contradictory, the development of the anti-vibration rubber capable of realizing both the low dynamic spring characteristics and the high damping characteristics is a big problem.

  In addition, in such an anti-vibration rubber, since it is necessary to support a predetermined load, a rubber having a high rubber hardness is usually used. However, in order to obtain a desired high rubber hardness, conventionally, A rubber composition in which carbon black or the like is blended with diene rubber such as natural rubber (NR) is used. However, when the hardness is increased by blending carbon black or the like as described above, the damping characteristics are also increased. Accordingly, there is a problem that the spring characteristics of the vibration-proof rubber as described above are increased.

  In addition, in order to obtain an anti-vibration rubber having an anti-vibration characteristic such as a low dynamic spring and high attenuation, a rubber material such as a natural rubber (NR) or other diene rubber is further blended with a rubber material that imparts high attenuation characteristics. Various countermeasures in terms of materials, such as changing the blending prescription, have been proposed, but none of them has achieved a reduction in the dynamic magnification of the obtained vibration-proof rubber.

In order to solve such a problem, the present inventors have developed a diene system such as NR having a rubber characteristic in which a loss coefficient (tan δ) indicating a damping characteristic at the time of inputting low frequency vibration (15 Hz) is 0.1 or more. In the anti-vibration rubber made of rubber, a patent application was previously filed for a method of producing an anti-vibration rubber capable of effectively reducing the dynamic magnification by introducing a functional group vulcanizable rubber as an island component in the sea-island structure ( Patent Document 1).
JP 2001-302846 A

  By the way, as a result of further research on the contents of the above-mentioned patent application, the present inventors have tried to further improve the damping characteristics, and thus the functional group vulcanizability with respect to the diene rubber for forming a matrix as a sea phase. It was determined that the rubber compounding ratio needs to be increased. However, when the compounding ratio of the functional group vulcanizable rubber is increased in this way, the tensile strength (Tb), elongation at break (Eb), etc. of the obtained anti-vibration rubber tend to decrease, and the strength of the anti-vibration rubber is reduced. There is a drawback that it becomes difficult to hold.

  The present invention has been made in view of such circumstances, and a method of manufacturing a vibration-proof rubber capable of realizing higher damping characteristics and low dynamic spring characteristics while maintaining excellent strength, and thereby The object is to provide the resulting anti-vibration rubber.

In order to achieve the above object, the present invention provides a diene rubber for forming a matrix as a sea phase and a rubber composition containing the following (A) to (C) as essential components, When the diene rubber and the rubber composition are kneaded and vulcanized at the same time, the diene rubber is not vulcanized by the following component (B) but only the following component (A) is vulcanized. A vulcanized product of the following component (A) is dispersed in a vulcanized diene rubber, and then a vulcanizing agent for a diene rubber is blended with the kneaded material in this state to obtain an unvulcanized diene. By vulcanizing the base rubber, the anti-vibration rubber is obtained in which the island phase mainly composed of the vulcanized product of the following component (A) is dispersed in the matrix mainly composed of the vulcanized diene rubber. The manufacturing method of the vibration rubber is the first gist. In addition, an anti-vibration rubber obtained by the above-described anti-vibration rubber manufacturing method, wherein an island phase mainly composed of the vulcanized product of the component (A) is dispersed in a matrix mainly composed of a vulcanized diene rubber. The anti-vibration rubber thus formed is a second gist.
(A) Functional group vulcanizable rubber for forming an island phase.
(B) A vulcanizing agent for functional group vulcanizable rubber.
(C) Liquid polymer.

  That is, the present inventors have intensively studied in order to obtain a vibration-proof rubber capable of realizing higher damping characteristics and low dynamic spring characteristics while maintaining excellent strength. In the course of the research, together with a functional group vulcanizable rubber for forming the island phase and a vulcanizing agent (vulcanizing agent for functional group vulcanizable rubber) that vulcanizes only this functional group vulcanizable rubber, I recalled that good results could be obtained by using plasticizers such as mineral oil, dioctyl phthalate (DOP), and dioctyl sebacate (DOS). Sex could not be expressed. As a result of further research, a liquid polymer that is insoluble in the diene rubber for forming the matrix as the sea phase and soluble in the functional group vulcanizable rubber for forming the island phase is When used with a functional group vulcanizable rubber and a vulcanizing agent for functional group vulcanizable rubber, the island phase itself exhibits high damping properties, so that higher damping characteristics can be realized and functional group vulcanizability can be achieved. Since it is not necessary to increase the blending ratio of rubber, it was found that excellent strength can be maintained without lowering the tensile strength (Tb), elongation at break (Eb), etc., and the present invention has been achieved.

  Thus, according to the manufacturing method of the vibration-proof rubber of the present invention, it is insoluble in the diene rubber for forming the matrix as the sea phase and soluble in the functional group vulcanizable rubber for forming the island phase. By using a liquid polymer together with the functional group vulcanizable rubber and the functional group vulcanizable rubber vulcanizing agent, a seawater in which island phases are dispersed in a matrix mainly composed of vulcanized diene rubber. -An anti-vibration rubber having an island structure can be obtained. For this reason, the anti-vibration rubber obtained by the production method of the present invention requires that the island phase itself develops high damping properties, realizes higher damping characteristics, and increases the blending ratio of the functional group vulcanizable rubber. Therefore, excellent strength can be maintained without a decrease in tensile strength (Tb), elongation at break (Eb), or the like. In addition, according to the production method of the present invention, the anti-vibration rubber exhibiting excellent anti-vibration performance as described above can be produced by a relatively simple operation, and the rubber compounding design of the anti-vibration rubber can be designed. There is also an advantage that the degree of freedom is advantageously expanded.

  In the anti-vibration rubber obtained by the manufacturing method of the present invention, it is possible to sufficiently cope with a plurality of types of vibrations having different frequencies. It can be suitably used in the required vibration transmission system.

  Further, when liquid polybutene or liquid acrylonitrile-butadiene rubber is used as the liquid polymer (C), the balance between the high damping characteristics and the low dynamic spring characteristics is improved.

  Further, when the blending ratio of the liquid polymer (C) is set within a range of 10 to 50 parts by weight with respect to 100 parts by weight of the functional group vulcanizable rubber (A), high damping characteristics and low The balance with the dynamic spring characteristics becomes better.

  Next, embodiments of the present invention will be described in detail.

The anti-vibration rubber production method of the present invention comprises preparing a diene rubber for forming a matrix as a sea phase and a rubber composition containing the following (A) to (C) as essential components. When the rubber and the rubber composition are kneaded and vulcanized at the same time, the diene rubber is not vulcanized by the component (B), only the component (A) is vulcanized, and the unvulcanized diene rubber The vulcanized product of component (A) is dispersed therein, and then a diene rubber vulcanizing agent is added to the kneaded product in this state to add the unvulcanized diene rubber. An anti-vibration rubber having a sea-island structure in which an island phase mainly composed of the vulcanized product of the component (A) is dispersed in a matrix mainly composed of a vulcanized diene rubber by vulcanization. It is a manufacturing method to obtain.
(A) Functional group vulcanizable rubber for forming an island phase.
(B) A vulcanizing agent for functional group vulcanizable rubber.
(C) Liquid polymer.

  Here, in the present invention, as the rubber composition forming the island phase, the liquid polymer (C) is used together with the functional group vulcanizable rubber (A) and the vulcanizing agent for functional group vulcanizable rubber (B). This is the greatest feature.

  In the present invention, the essential component refers to an optional component and is a component that is necessarily contained in terms of configuration, and is not subject to quantitative restrictions. Further, the main component means a component that usually occupies a majority of the whole, and includes the case where the whole consists of only the main component.

  In the present invention, the functional group vulcanizable rubber (A) for forming the island phase refers to a rubber having a functional group vulcanized by the vulcanizing agent for functional group vulcanizable rubber (B), The vulcanization is required to be performed in a vulcanization system different from the diene rubber for forming the matrix as the sea phase.

  Such functional group vulcanizable rubber (A) is not particularly limited, and examples thereof include halogenated butyl rubber (halogenated IIR) such as chlorinated butyl rubber and brominated butyl rubber, and maleic acid-modified ethylene-propylene rubber ( Examples thereof include maleic acid-modified EPM), chloroprene rubber (CR), carboxyl-modified acrylonitrile-butadiene rubber (carboxyl-modified NBR), chlorosulfonated polyethylene (CSM), fluorine rubber, and acrylic rubber. These may be used alone or in combination of two or more. Among these, halogenated IIR is preferably used because it can advantageously realize low dynamic magnification.

  The blending ratio of the functional group vulcanizable rubber (A) is 50% of the total amount of the diene rubber for forming the matrix as the sea phase and the functional group vulcanizable rubber (A). % Is preferably set, and particularly preferably in the range of 10 to 40% by weight. That is, when the blending ratio of the functional group vulcanizable rubber (A) exceeds 50% by weight of the total amount, the resulting anti-vibration rubber has reduced tensile strength (Tb), elongation at break (Eb), etc. This is because it is difficult to maintain the strength and it is difficult to achieve a low dynamic magnification.

  Next, as the vulcanizing agent for functional group vulcanizable rubber (B), only the functional group vulcanizable rubber (A) is used without vulcanizing a diene rubber for forming a matrix as a sea phase. Is not particularly limited, for example, resin-based vulcanizing agents such as alkylphenol resins and modified alkylphenol resins, metal oxide-based vulcanizing agents such as zinc oxide and magnesium oxide, hexamethylenediamine carbamate, etc. And amine vulcanizing agents such as Among these, an appropriate one is selected and used according to the type of rubber.

  In the present invention, a vulcanization accelerator or a vulcanization acceleration aid may be used in combination with the vulcanizing agent for functional group vulcanizable rubber (B).

  Examples of the vulcanization accelerator include 4,4-dithio-bis-dimorpholine, tellurium diethyldithiocarbamate, zinc dimethyldithiocarbamate (ZnMDC), zinc diethyldithiocarbamate (ZnEDC), 2-mercaptoimidazoline, pentaerythritol, diester. Examples include pentamethylene thiuram tetrasulfide, diortolyl guanidine, calcium hydroxide, and zinc oxide. These may be used alone or in combination of two or more.

  Moreover, as said vulcanization | cure acceleration | stimulation adjuvant, a stearic acid etc. are mention | raise | lifted, for example. These may be used alone or in combination of two or more.

  Next, in the present invention, the liquid polymer (C) is used together with the functional group vulcanizable rubber (A) and the functional group vulcanizable rubber vulcanizing agent (B). In the present invention, the liquid polymer (C) is insoluble in the diene rubber for forming the matrix as the sea phase and can be used in the functional group vulcanizable rubber (A) for forming the island phase. It means a polymer that is soluble.

  Such a liquid polymer (C) is not particularly limited. For example, liquid polybutene, liquid NBR, liquid butadiene rubber (liquid BR), liquid isoprene rubber (liquid IR), liquid ethylene-propylene-diene rubber (liquid EPDM) Etc. Among these, liquid polybutene and liquid NBR are preferably used in terms of damping characteristics.

  The number average molecular weight (Mn) of the liquid polymer (C) is preferably in the range of 500 to 50,000, particularly preferably in the range of 1,000 to 10,000. That is, when the number average molecular weight (Mn) of the liquid polymer (C) is out of the range of 500 to 50,000, it is difficult to achieve higher attenuation.

  Further, the blending ratio of the liquid polymer (C) is preferably within a range of 10 to 50 parts, particularly preferably with respect to 100 parts by weight of the functional group vulcanizable rubber (A) (hereinafter abbreviated as “part”). Is in the range of 15 to 45 parts. That is, when the blending ratio of the liquid polymer (C) is less than 10 parts, it becomes difficult to express higher damping characteristics. Conversely, when the amount is increased from 50 parts, the damping characteristics are improved, but the tensile strength (Tb ) And elongation at break (Eb) are deteriorated, and it is difficult to obtain a vibration-proof rubber having desired characteristics.

  Next, the diene rubber for forming the matrix as the sea phase is not particularly limited. For example, natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber ( SBR), acrylonitrile-butadiene rubber (NBR), ethylene-propylene-diene rubber (EPDM) and the like. These may be used alone or in combination of two or more. Among these, NR alone, a blend (mixture) of NR and BR, or a blend of NR and SBR is preferably used in terms of vibration-proof performance and durability.

  The vulcanizing agent for vulcanizing the diene rubber (diene rubber vulcanizing agent) is not particularly limited, and for example, sulfur or the like is used.

  In the vulcanization of the diene rubber, a vulcanization accelerator or a vulcanization accelerator aid may be used together with the diene rubber vulcanizing agent, and a reinforcing agent, a softening agent, an aging agent may be used. Various compounding agents for rubber such as an inhibitor may be appropriately blended.

  The vulcanization accelerator used together with the diene rubber vulcanizing agent is not particularly limited. For example, Nt-butyl-2-benzothiazolylsulfenamide (BBS), N-cyclohexyl-2- Sulfenamides such as benzothiazolylsulfenamide (CBS) and N-oxydiethylene-2-benzothiazolesulfenamide (OBS); dithiocarbamines such as zinc dimethyldithiocarbamate (ZnMDC) and zinc diethyldithiocarbamate (ZnEDC) Acid salts; thiurams such as tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide (TETD), and tetrabutylthiuram disulfide (TBTD) are used. These may be used alone or in combination of two or more.

  Moreover, there is no limitation in particular as a vulcanization acceleration adjuvant used with the said diene rubber vulcanizing agent, For example, a zinc oxide, a stearic acid, etc. are mention | raise | lifted, and it is used individually or in combination of 2 or more types.

  Examples of the reinforcing agent include carbon black. The carbon black is not particularly limited, and examples thereof include various grades of carbon black such as SAF class, ISAF class, HAF class, MAF class, FEF class, GPF class, SRF class, FT class, and MT class. . These may be used alone or in combination of two or more.

  Examples of the softening agent include naphthenic process oil.

  Examples of the anti-aging agent include diphenylamine-based anti-aging agents such as a reaction product of acetone and diphenylamine, phenylenediamine-based anti-aging agents such as N-phenyl-N′-isopropyl-p-phenylenediamine, and carbamate-based aging. Examples thereof include an antioxidant, a phenolic antioxidant, a quinoline antioxidant, an imidazole antioxidant, and waxes.

  Next, the production method of the vibration-proof rubber of the present invention will be described more specifically. That is, the functional group vulcanizable rubber (A) for forming a matrix as the island phase, the functional group vulcanizable rubber vulcanizing agent (B), the liquid polymer (C), and Accordingly, a rubber composition (masterbatch) is prepared by appropriately blending a vulcanization accelerator and a vulcanization acceleration aid and kneading them with a roll machine, a Banbury mixer, or the like. Subsequently, after supplying this rubber composition (masterbatch) and the diene rubber for forming the matrix as the sea phase into a kneading apparatus such as Banbury, a predetermined time (preferably 3 to 15 minutes) ) Heat at a predetermined temperature (preferably 150 to 180 ° C.) while uniformly kneading. By such an operation, only the functional group vulcanizable rubber (A) in the rubber composition (masterbatch) can be vulcanized without vulcanizing the diene rubber. Next, the above diene rubber vulcanizing agent is blended, and if necessary, a vulcanization accelerator, a vulcanization accelerating aid, an anti-aging agent, a reinforcing agent, a softening agent, etc. are appropriately blended, and a roll machine, etc. After kneading and mixing uniformly, the desired vibration-proof rubber can be obtained by vulcanization molding by press vulcanization or the like under predetermined conditions (preferably 10 to 30 minutes).

  According to the production method of the present invention, the island phase mainly composed of the vulcanized product of the functional group vulcanizable rubber (A) is uniformly dispersed in the matrix mainly composed of the vulcanized diene rubber. An anti-vibration rubber having a sea-island structure can be obtained.

  Here, the size of the vulcanized functional group vulcanizable rubber (A) in the island phase mainly composed of the vulcanizate of the functional group vulcanizable rubber (A) is not particularly limited and is required. The average particle size is preferably within the range of 0.1 to 100 μm, and particularly preferably the average particle size. Is in the range of 0.1 to 30 μm. That is, if the average particle diameter is less than 0.1 μm, it is difficult to sufficiently achieve the desired vibration isolation characteristics. Conversely, if the average particle diameter exceeds 100 μm, the physical properties of the vibration isolation rubber to be obtained can be improved. This is because there is a risk of adverse effects.

  The average particle diameter measurement method is not particularly limited. For example, each vulcanized rubber particle is observed with a scanning electron microscope (SEM), a scanning probe microscope (SPM), etc. It can measure by measuring and calculating | requiring the average value of those particle diameters.

  In the above production method, the functional group vulcanizable rubber (A), the functional group vulcanizable rubber vulcanizing agent (B), the liquid polymer (C) and the like are blended in advance and kneaded. Then, after preparing the rubber composition (masterbatch), the rubber composition (masterbatch) and the diene rubber were supplied to the kneading apparatus, but the invention is not limited to such a masterbatch method, For example, the rubber composition containing the components (A) to (C) as essential components and the diene rubber for forming a matrix as the sea phase may be simultaneously supplied into the kneading apparatus. However, in the present invention, the master batch method as described above is preferable, and by adopting such a method, the kneading time can be shortened, and the functional group vulcanization is performed in the matrix (sea phase). It is possible to more uniformly disperse the island phase mainly composed of the vulcanizate of the functional rubber (A), and the vibration isolation characteristics are further improved.

  Further, in the present invention, a predetermined metal fitting made of an iron material, an aluminum material or the like is bonded at the time of vulcanization or after vulcanization of the diene rubber for forming the matrix as the sea phase. Accordingly, it is possible to obtain a vibration-proof rubber with a metal fitting.

  According to the production method of the present invention, it is possible to obtain an anti-vibration rubber that can exhibit higher damping properties. The damping characteristic of the vibration-proof rubber obtained by the production method of the present invention preferably has a loss coefficient (tan δ) value of 0.17 or more at the time of vibration input at 15 Hz, particularly preferably a loss coefficient (tan δ) value. It is 0.18 or more.

  Further, the hardness (JIS type A hardness) of the vibration-proof rubber obtained by the production method of the present invention is preferably 40 or more, particularly preferably 45 or more. That is, if the hardness (JIS type A hardness) is less than 40, it will be difficult to satisfy the demand from the use of the vibration-proof rubber.

  The use of the anti-vibration rubber of the present invention thus obtained is not particularly limited. For example, it is suitably used for engine mounts, body mounts, member mounts, stabilizer bushes, suspension bushes and the like used for vehicles such as automobiles. Can be used.

  Next, examples will be described together with comparative examples.

  First, prior to Examples and Comparative Examples, the following masterbatch materials were prepared.

[Functional group vulcanizable rubber]
Cl-IIR (manufactured by JSR, chlorobutyl 1066)

[Liquid polymer A]
Liquid polybutene (manufactured by Nippon Petrochemical Co., Ltd., polybutene HV1900, Mn: 2900)

[Liquid polymer B]
Liquid NBR (Nippon Zeon, Nipol 1312, Mn: 3100)

[Low molecular weight plasticizer]
DOP (manufactured by Mitsubishi Kasei Vinyl, DOP, molecular weight: 390.56)

[Vulcanizing agent for functional group vulcanizable rubber]
Zinc oxide (made by Sakai Chemical Industry Co., Ltd., 2 types of zinc oxide)

[Vulcanization accelerator]
Zinc dimethyldithiocarbamate (ZnMDC) [Ouchi Shin Chemical Co., Ltd., Noxeller PZ]

[Vulcanization accelerator]
Stearic acid (manufactured by Kao Corporation, Lunac S30)

  Next, using the above materials, they were blended at the ratios shown in Table 1 and Table 2 below to prepare a master batch.

  Prior to the examples and comparative examples, the following materials were prepared.

[Vulcanizing agent for diene rubber (sulfur)]
JIS Class 1 equivalent (Tsurumi Chemical Co., Ltd.)

[Vulcanization accelerator A]
Stearic acid (manufactured by Kao Corporation, Lunac S30)

[Vulcanization acceleration aid B]
Zinc oxide (made by Sakai Chemical Industry Co., Ltd., 2 types of zinc oxide)

[Anti-aging agent]
Wax (Sannok, manufactured by Ouchi Shinsei Chemical Co., Ltd.)

(Reinforcing agent)
Carbon black (manufactured by Tokai Carbon Co., Seast SO)

[Softener]
Naphthenic process oil (Nihon San Oil Co., Ltd., Sunsen 410)

[Vulcanization accelerator]
N-cyclohexyl-2-benzothiazolyl disulfenamide (CBS) [manufactured by Sanshin Chemical Industry Co., Ltd., Sunseller CZ]

  Next, a vibration-proof rubber was produced using each material as follows.

[Examples 1-6, Comparative Examples 2-4]
Natural rubber and masterbatch were blended in the blending ratios shown in Table 3 and Table 4 below, and these were fed into a banbury where heat kneading was possible, and then kneaded uniformly for 3 to 15 minutes. Heated at a temperature of ~ 180 ° C. Thereby, only the chlorinated butyl rubber in the master batch was vulcanized without vulcanizing the natural rubber. Next, the proportions shown in Table 3 and Table 4 below for the remaining components (diene rubber vulcanizing agent, vulcanization accelerating aid, anti-aging agent, reinforcing agent, softening agent, vulcanizing accelerator) The mixture was kneaded with a Banbury mixer and a roll machine and mixed uniformly to prepare a preliminary sample (anti-vibration rubber composition).

[Comparative Example 1]
Each component shown in Table 4 below is blended in the proportions shown in the same table, and these are kneaded with a Banbury mixer and a roll machine and blended uniformly to prepare a preliminary sample (anti-vibration rubber composition). did.

  Using the thus obtained preliminary samples of Examples and Comparative Examples, each characteristic was evaluated according to the following criteria. These results are shown in Tables 3 and 4 below. The ratio of Cl-IIR in the total amount of NR and Cl-IIR is shown in the table.

[Dynamic factor (Kd ₁₀₀ / Ks)]
Each preliminary sample was press vulcanized under vulcanization conditions at 160 ° C. for 20 minutes to prepare a vulcanized rubber sample having a cylindrical shape (diameter 50 mm, height 25 mm), and then the upper and lower surfaces of the vulcanized rubber sample. On the other hand, a test piece was prepared by adhering a pair of steel disk fittings (diameter 60 mm, thickness 6 mm) with an adhesive. Next, an axial load is applied to the test piece, the load is compressed by 5.5 mm in the axial direction, once reduced, and then compressed again by 5.5 mm, and the load-deflection characteristics in the second loading process. Was measured, and a load-deflection curve was created based thereon. From this curve, load values P1 and P2 (unit: N) are read when the deflection is 1.25 mm and 3.75 mm, respectively, and according to Ks = (P2 -P1) /2.5 Spring constant: Ks (N / mm) was calculated. Separately, after compressing each test piece by 2.5 mm in the axial direction, the amplitude around the compressed position of 2.5 mm from the bottom of the compressed test piece is set at a constant of ± 0.05 mm. A test for applying displacement harmonic compression vibration at a frequency of 100 Hz was performed, and the dynamics at 100 Hz were determined in accordance with “Non-resonant method (a)” in “Testing method of vibration-proof rubber” of JIS-K-6385-1995. Spring constant (storage spring constant): Kd ₁₀₀ (N / mm) was determined. The dynamic magnification (Kd ₁₀₀ / Ks) was calculated from this Kd ₁₀₀ and the Ks obtained above. In addition, that the value of this dynamic magnification is small means that the target test piece has low dynamic spring characteristics with respect to vibration of 100 Hz.

[Loss factor (tan δ)]
A test piece was prepared in accordance with the dynamic magnification evaluation method. Next, in a state where the test piece is compressed by 2.5 mm in the axial direction, a constant displacement harmonic compression vibration having an amplitude of ± 0.5 mm centered on the compression position is applied at a frequency of 15 Hz from below the test piece. The test was conducted, and the loss factor (tan δ) at 15 Hz was determined in accordance with “Non-resonant method (a)” in “Test method for anti-vibration rubber” of JIS-K-6385-1995. In addition, it can be understood that the value of this loss factor is large that the target test piece exhibits high attenuation with respect to vibration of 15 Hz.

[Hardness (JIS-A)]
Using each preliminary sample, a test piece (thickness 2 mm) defined in “Durometer Hardness Test” in “Vulcanized Rubber Physical Test Method” of JIS-K-6253-1997 was prepared. Using each test piece, the hardness (JIS-A) of the test piece was measured with a type A durometer according to the “durometer hardness test” in the “vulcanized rubber physical test method” of the above JIS-K-6253-1997. It was measured.

[Tensile test]
Using each preliminary sample, a dumbbell-shaped test piece (No. 3 type) prescribed in “Tensile test method for vulcanized rubber” of JIS-K-6251-1993 was prepared and used as a test piece. Using each test piece, in accordance with the test method defined in JIS-K-6251-1993, the test piece was pulled until it was cut by a predetermined tensile tester, and the maximum stress until it was cut (tensile strength: Tb ) And elongation at break (breaking elongation: Eb).

  From the above results, each of the products of Examples had a loss factor as high as 0.168 or higher, so that higher damping characteristics could be expressed and low dynamic spring characteristics could also be expressed. Further, since the blending ratio of chlorinated butyl rubber to natural rubber was not high, the tensile strength (Tb) and elongation at break (Eb) were also high, and excellent strength could be maintained. The particle size of vulcanized chlorinated butyl rubber dispersed in a matrix containing vulcanized natural rubber as a main component was measured and the average value was determined. It was confirmed that the thickness was about 5 to 5 μm.

  On the other hand, since the product of Comparative Example 1 does not contain chlorinated butyl rubber, it does not form a sea-island structure, has a loss factor of less than 0.1, and can exhibit high attenuation characteristics. There wasn't. The product of Comparative Example 2 had no problem in terms of strength and dynamic magnification, but had a slightly small loss coefficient and could not realize higher attenuation characteristics. In Comparative Example 3, the blending ratio of chlorinated butyl rubber to natural rubber is too high, so the tensile strength (Tb) and elongation at break (Eb) are small, the strength is reduced, and the value of dynamic magnification is too high. The low dynamic spring characteristics were inferior. Although the comparative example 4 product mix | blended the low molecular weight plasticizer (DOP) in the masterbatch, it was not able to express the high attenuation | damping property.

  The anti-vibration rubber can be suitably used for an engine mount, a body mount, a member mount, a stabilizer bush, a suspension bush, and the like used in a vehicle such as an automobile, for example, by the production method of the present invention.

Claims (4)

A diene rubber for forming a matrix as a sea phase and a rubber composition containing the following (A) to (C) as essential components are prepared, and at the same time the diene rubber and the rubber composition are kneaded. In the vulcanization, the diene rubber is not vulcanized by the following component (B), but only the following component (A) is vulcanized, whereby the following (A) The vulcanized diene system is prepared by dispersing the vulcanized product of the components and then blending the kneaded product in this state with a vulcanizing agent for diene rubber and vulcanizing the unvulcanized diene rubber. A method for producing a vibration-proof rubber, comprising obtaining a vibration-proof rubber in which an island phase mainly composed of a vulcanized product of the following component (A) is dispersed in a matrix containing rubber as a main component.
(A) Functional group vulcanizable rubber for forming an island phase.
(B) A vulcanizing agent for functional group vulcanizable rubber.
(C) Liquid polymer.   The method for producing a vibration-proof rubber according to claim 1, wherein the liquid polymer (C) is liquid polybutene or liquid acrylonitrile-butadiene rubber.   The vibration isolation according to claim 1 or 2, wherein a blending ratio of the liquid polymer (C) is set within a range of 10 to 50 parts by weight with respect to 100 parts by weight of the functional group vulcanizable rubber (A). How to make rubber.   It is a vibration-proof rubber obtained by the manufacturing method as described in any one of Claims 1-3, Comprising: The vulcanizate of the said (A) component is a main component in the matrix which has a vulcanized diene type rubber as a main component. An anti-vibration rubber characterized in that the island phase is dispersed.