JP2005239813A - Method for producing vibration-proof rubber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing vibration-proof rubber, by which rubber having a low dynamic-to-static modulus ratio is efficiently obtained. <P>SOLUTION: This method for producing the vibration-proof rubber comprises a process for kneading diene-based rubber with a peptizer. Carbon black is added to the rubber simultaneously with the addition of the peptizer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a vibration isolating rubber, and more particularly to a method for manufacturing a vibration isolating rubber used for an engine mount, a suspension bush, and the like for supporting an engine of an automobile or the like and suppressing vibration transmission. is there.

In general, in a vibration-proof rubber used for an engine mount, a suspension bush, or the like for supporting an engine of an automobile or the like and suppressing vibration transmission, a low dynamic magnification is required as one of important performances. Yes. In order to achieve such a low dynamic magnification, conventionally, a blend rubber obtained by mixing 50 to 80 parts of natural rubber and 50 to 20 parts of terminal-modified butadiene rubber has a DBP oil absorption of 100 ml / 100 g or more, and An anti-vibration rubber composition for vehicles is proposed in which 35 to 70 parts of carbon black having an iodine adsorption of 45 mg / g or less is added (see Patent Document 1).
JP-A-8-73658

  However, since the vibration-proof rubber composition for vehicles described in Patent Document 1 is blended with a natural rubber and a terminal-modified butadiene rubber, the physical properties of the natural rubber deteriorate and the durability deteriorates. is there.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a method for producing a vibration-proof rubber capable of efficiently obtaining a rubber having a low dynamic magnification.

  In order to achieve the above object, a method for producing a vibration isolating rubber according to the present invention is a method for producing a vibration isolating rubber comprising a step of adding a kneading agent to a diene rubber and kneading the rubber. The composition is such that carbon black is added simultaneously with the addition of the agent.

  The inventors of the present invention have made extensive studies in order to obtain an antivibration rubber having a low dynamic magnification. As a result, when adding a chelating agent to a diene rubber and kneading it, it is possible to efficiently obtain a rubber with a low dynamic magnification by adding carbon black at the same time as the addition of the above-mentioned chelating agent. And the present invention has been reached. The reason for this is not clear, but is presumed as follows. That is, when a chelating agent is added to a diene rubber and kneaded, the diene rubber is cut by the chelating agent to generate radicals, and the diene rubber is activated. When carbon black is added in the activated state of this diene rubber, a chemical bond is formed between the generated radical and carbon black (functional group of carbon black), resulting in a vibration-proof rubber with low dynamic magnification. It is guessed that it is possible.

  The anti-vibration rubber manufacturing method of the present invention adds a carbon black simultaneously with the addition of the above-mentioned chelating agent when adding the chelating agent to the diene rubber. Can be obtained efficiently.

  Moreover, when the thing which has dibenzamide diphenyl disulfide as an essential component is used as said chelating agent, since practicing power is large, an effect can be exhibited in a short time.

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

  The present invention is a method for producing a vibration-proof rubber comprising a step of adding a quenching agent (component B) to a diene rubber (component A) and kneading.

  In the present invention, carbon black (C component) is also added simultaneously with the addition of the above-mentioned chelating agent (B component), which is the greatest feature.

  Here, the term “simultaneous” is not limited to the case where a chelating agent (component B) and carbon black (component C) are added at the same time literally. After adding the chelating agent (component B), carbon This also includes the case where black (component C) is added within 5 minutes. That is, within 5 minutes after the addition of the chelating agent (component B), since the diene rubber (component A) is in an activated state as described above, it is chemically bonded to carbon black (component C). This is because a sufficiently low dynamic magnification can be achieved.

  The diene rubber (component A) 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 is preferably used in terms of vibration proof performance and durability.

  Next, as the peptizer (component B) used together with the diene rubber (component A), there is no particular limitation as long as the effect as a peptizer for diene rubber (component A) can be obtained. For example, o, o'-dibenzamide diphenyl disulfide, zinc salt of 2-benzamidothiophenol and the like can be mentioned. These may be used alone or in combination of two or more. Among these, those having o, o'-dibenzamide diphenyl disulfide as an essential component are preferably used in that an effect can be obtained in a small amount. Specific examples of the chelating agent (component B) include o, o′-dibenzamide diphenyl disulfide (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Noctizer SS).

  The blending ratio of the above-mentioned chelating agent (component B) to the diene rubber (component A) varies depending on the type of diene rubber (component A) used and the type of chelating agent (component B). In general, it is preferable that the blending ratio of the peptizer (component B) is slightly higher in the case of synthetic rubber than in the case of natural rubber. The blending ratio of the chelating agent (component B) is preferably in the range of 0.02 to 2 parts, particularly preferably 100 parts by weight (hereinafter abbreviated as “part”) of the diene rubber (component A). It is in the range of 0.05 to 1 part. That is, when the blending ratio of the above-mentioned chelating agent (component B) is less than 0.02 part, the effect of mastication of the diene rubber (component A) is small, and the diene rubber (component A) due to the generation of radicals. When the activation time tends to be shortened and, conversely, when the blending ratio of the chelating agent (component B) exceeds 2 parts, molecular cutting of the diene rubber (component A) frequently occurs, and the static spring constant is This is because there is a possibility that the dynamic magnification will deteriorate.

  Next, the blending ratio of the carbon black (component C) added simultaneously with the addition of the above-mentioned chelating agent (component B) is preferably in the range of 10 to 100 parts with respect to 100 parts of the diene rubber (component A). Especially preferably, it is the range of 30-80 parts. That is, when the blending ratio of the carbon black (component C) is less than 10 parts, the effect of reducing the dynamic magnification tends to be reduced. Conversely, the blending ratio of the carbon black (component C) exceeds 100 parts. This is because the Mooney viscosity increases and the workability tends to deteriorate.

  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. Among these, FEF grade carbon black is suitably used from the balance of global supply, cost, durability, and vibration isolation performance.

  In the present invention, a vulcanization accelerator, a vulcanization aid, an anti-aging agent, a processing aid, together with the diene rubber (component A), a peptizer (component B) and carbon black (component C). It is also possible to add a softener or the like as needed.

  The vulcanization accelerator is not particularly limited, and examples thereof include thiazole series, sulfenamide series, thiuram series, aldehyde ammonia series, aldehyde amine series, guanidine series, and thiourea series vulcanization accelerators. These may be used alone or in combination of two or more. Among these, a sulfenamide-based vulcanization accelerator is preferable from the viewpoint of excellent crosslinking reactivity.

  Examples of the thiazole vulcanization accelerator include dibenzothiazyl disulfide (MBTS), 2-mercaptobenzothiazole (MBT), 2-mercaptobenzothiazole sodium salt (NaMBT), and 2-mercaptobenzothiazole zinc salt (ZnMBT). Etc. These may be used alone or in combination of two or more. Among these, dibenzothiazyl disulfide (MBTS) is preferably used because it is particularly excellent in cross-linking reactivity.

  Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzodiallylsulfenamide, N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-oxydiethyl-2-benzo Examples thereof include thiazole sulfenamide (OBS), Nt-butyl-2-benzothiazoyl sulfenamide (BBS), N, N′-dicyclohexyl-2-benzothiazoyl sulfenamide, and the like.

  Examples of the thiuram vulcanization accelerator include tetramethyl thiuram disulfide (TMTD), tetraethyl thiuram disulfide (TETD), tetrabutyl thiuram disulfide (TBTD), and the like.

  The blending amount of the vulcanization accelerator is preferably in the range of 0.3 to 7 parts, particularly preferably in the range of 0.5 to 5 parts with respect to 100 parts of the diene rubber (component A). . That is, if the vulcanization accelerator is less than 0.3 part, the crosslinking reactivity tends to be inferior, and conversely if the vulcanization accelerator exceeds 7 parts, the physical properties of rubber (breaking strength, breaking elongation) decrease. It is because there is a possibility of doing.

  The vulcanization aid is not particularly limited, and examples thereof include zinc white (ZnO) and magnesium oxide. These may be used alone or in combination of two or more.

  The amount of such a vulcanization aid is preferably in the range of 1 to 20 parts, particularly preferably in the range of 3 to 10 parts, with respect to 100 parts of the diene rubber (component A).

  Examples of the anti-aging agent include carbamate anti-aging agents, phenylenediamine anti-aging agents, phenol anti-aging agents, diphenylamine anti-aging agents, quinoline anti-aging agents, imidazole anti-aging agents, and waxes. Etc.

  The amount of such an anti-aging agent is preferably in the range of 1 to 7 parts, particularly preferably in the range of 2 to 5 parts, with respect to 100 parts of the diene rubber (component A).

  Examples of processing aids include stearic acid, fatty acid esters, fatty acid amides, hydrocarbon resins, and the like.

  The amount of such a processing aid is preferably in the range of 1 to 5 parts, particularly preferably in the range of 1 to 3 parts, per 100 parts of the diene rubber (component A).

  The method for producing the vibration-proof rubber of the present invention will be specifically described. That is, to the above diene rubber (component A), a chelating agent (component B) and carbon black (component C) are added simultaneously, and if necessary, stearic acid, zinc white (ZnO), etc. It mix | blends suitably and knead | mixes for a predetermined time (preferably 3 to 5 minutes) at predetermined temperature (preferably 140-160 degreeC) using a Banbury mixer etc. Next, a vulcanization accelerator, a vulcanizing agent, and the like are blended as necessary, and an open roll or the like is used at a predetermined temperature (preferably 50 to 70 ° C.) for a predetermined time (preferably 3 to 5 minutes). ) A vibration-proof rubber composition is prepared by kneading. Subsequently, the intended vibration-proof rubber can be obtained by subjecting the obtained vibration-proof rubber composition to press vulcanization or the like under predetermined conditions.

  Note that the simultaneous addition of the chelating agent (component B) is not limited to the case where the chelating agent (component B) and carbon black (component C) are added literally at the same time as described above. This also includes the case where carbon black (C component) is added within 5 minutes after the addition of the chelating agent (B component).

  The use of the anti-vibration rubber thus obtained is not particularly limited, but it can be reduced in the dynamic magnification, and is therefore suitable for an engine mount, a stabilizer bush, a suspension bush, etc. used in a vehicle such as an automobile. Can be used.

  Next, examples will be described together with comparative examples.

  100 parts of natural rubber, 0.08 part of o, o'-dibenzamide diphenyl disulfide (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Noctizer SS) as a chelating agent, and FEF grade carbon black (manufactured by Tokai Carbon Co., Ltd., Seast SO) ) 40 parts at the same time, 1 part of stearic acid (manufactured by Kao Corporation, Lunac S30) and 5 parts of zinc white (ZnO) were blended and kneaded at 150 ° C. for 4 minutes using a Banbury mixer. Next, 1 part of N-cyclohexyl-2-benzodiallylsulfenamide (manufactured by Sanshin Chemical Industry Co., Ltd., Sunsala CZ-G), which is a vulcanization accelerator, and 2.5 parts of vulcanizing agent (sulfur) are blended. And using an open roll, it knead | mixed for 4 minutes at 50 degreeC, and prepared the vibration proof rubber composition.

  100 parts of natural rubber, 0.08 part of o, o'-dibenzamide diphenyl disulfide (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Noctizer SS) and 1 part of stearic acid (manufactured by Kao Corporation, Lunac S30) And 5 parts of zinc white (ZnO) were blended and kneaded at 150 ° C. for 1 minute using a Banbury mixer. Subsequently, 40 parts of FEF grade carbon black (manufactured by Tokai Carbon Co., Ltd., Seast SO) was added within 5 minutes after the above-mentioned chelating agent was added, and kneaded at 150 ° C. for 3 minutes using a Banbury mixer. Next, 1 part of N-cyclohexyl-2-benzodiallylsulfenamide (manufactured by Sanshin Chemical Industry Co., Ltd., Sunsala CZ-G), which is a vulcanization accelerator, and 2.5 parts of vulcanizing agent (sulfur) are blended. And using an open roll, it knead | mixed for 4 minutes at 50 degreeC, and prepared the vibration proof rubber composition.

[Comparative example]
100 parts of natural rubber, 0.08 part of o, o'-dibenzamide diphenyl disulfide (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., Noctizer SS) as a chelating agent and 1 part of stearic acid (manufactured by Kao Corporation, Lunac S30) And 5 parts of zinc white (ZnO) were blended and kneaded at 150 ° C. for 1 minute using a Banbury mixer. Subsequently, 10 parts after adding the above-mentioned chelating agent, 40 parts of FEF grade carbon black (manufactured by Tokai Carbon Co., Ltd., Seast SO) was added and kneaded at 150 ° C. for 3 minutes using a Banbury mixer. Next, 1 part of N-cyclohexyl-2-benzodiallylsulfenamide (manufactured by Sanshin Chemical Industry Co., Ltd., Sunsala CZ-G), which is a vulcanization accelerator, and 2.5 parts of vulcanizing agent (sulfur) are blended. And using an open roll, it knead | mixed for 4 minutes at 50 degreeC, and prepared the vibration proof rubber composition.

  Using the anti-vibration rubber compositions of Examples and Comparative Examples thus obtained, each characteristic was evaluated according to the following criteria. These results are also shown in Table 1 below.

[Initial physical properties]
Each anti-vibration rubber composition was press-molded under conditions of 150 ° C. × 20 minutes and punched with a JIS No. 5 dumbbell to produce a anti-vibration rubber sheet having a thickness of 2 mm. And using this anti-vibration rubber sheet, break strength (TB), elongation at break (EB), and hardness (JIS A) were measured according to JIS K 6251.

[Dynamic magnification]
Each rubber composition was vulcanized at 150 ° C. for 30 minutes to produce a cylindrical test piece (diameter 50 mm, height 25 mm), and circular fittings (diameter 60 mm, thickness 6 mm) on the upper and lower surfaces thereof. The static spring constant (Ks) and the dynamic spring constant (Kd ₁₀₀ ) were measured to determine the dynamic magnification (Kd ₁₀₀ / Ks). That is, the static spring constant was calculated by reading the load at the time of distortion of 1.5 mm and 3.5 mm from the second load-deflection curve after compressing the test piece by 7 mm in the axial direction of the cylinder. The dynamic spring constant is determined by compressing the test piece by 2.5 mm in the axial direction, and centering on the position of the 2.5 mm compression, constant displacement harmonic compression vibration with an amplitude of ± 0.05 mm at a frequency of 100 Hz from below. In addition, the dynamic load was measured with a load cell attached above the test piece and calculated according to JIS K 6394. And the dynamic magnification was calculated | required from ratio of a static spring constant and a dynamic spring constant.

  From the above results, the example products were excellent in initial physical properties, small in dynamic magnification, and excellent in vibration-proof performance.

  On the other hand, the comparative example product had a high dynamic magnification and was inferior in vibration-proof performance.

  Since the vibration-proof rubber obtained by the production method of the present invention has a low dynamic magnification, it can be suitably used for engine mounts, stabilizer bushes, suspension bushes and the like used in vehicles such as automobiles.

Claims (2)

  An anti-vibration rubber manufacturing method comprising a step of adding a kneading agent to a diene rubber and kneading, wherein carbon black is added at the same time as the addition of the above-mentioned anti-shrinking agent. Manufacturing method.   The method for producing a vibration-proof rubber according to claim 1, wherein the chelating agent contains dibenzamide diphenyl disulfide as an essential component.