Coating rubber composition and vibration energy absorption unit

Abstract

To provide a coating rubber composition capable of forming a coating rubber layer with superior bonding strength to a flange and superior resistance to fracture, particularly under high-strain deformation.SOLUTION: A coating rubber composition is used for forming a coating rubber layer that coats the exposed surface of a damping rubber member included in a vibration energy absorption unit. Based on 100 pts.mass of base rubber including halogenated butyl rubber, the composition contains 15 pts.mass or more and 70 pts.mass or less of silica.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coating rubber composition and a vibration energy absorbing unit using the same in a coating rubber layer. [Background technology]

[0002] A known example of a vibration energy absorbing unit used for seismic isolation or vibration control of structures such as buildings and bridges is one that includes a pair of flanges made of steel plates or the like and a damping rubber member interposed between the flanges. The pair of flanges and the damping rubber member are integrated with each other by vulcanization adhesion or the like.

[0003] The vibration energy absorption unit is incorporated into a structure with one of a pair of flanges fixed to the foundation beneath the structure and the other fixed to the structure. When an earthquake occurs and the flange on the foundation side vibrates, the damping rubber member between the two flanges undergoes large deformation, preventing the vibration from being transmitted to the structure. Furthermore, the damping action of the damping rubber member quickly attenuates the vibration of the structure. As a result, the structure is seismically isolated and vibration-controlled.

[0004] In order to prevent damage to the internal rubber and deterioration over time, the damping rubber member is adapted to cover the surface (outer periphery) that is not in contact with the pair of flanges with a coating rubber layer that has gas barrier properties, weather resistance, etc. Various compositions for such a coating rubber layer have been studied.

[0005] For example, Patent Document 1 discloses a coated rubber molded article characterized in that a coating layer made of layered clay mineral filler dispersed in rubber is formed on the surface of the rubber molded article.

[0006] Patent Document 2 discloses a coating rubber composition that uses two types of rubber, a halogenated butyl rubber and an ethylene-propylene-diene copolymer rubber, in combination as the rubber component, and is characterized by compounding surface-treated calcium carbonate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-34396 A [Patent Document 2] JP 2012-126818 A Summary of the Invention [Problem to be solved by the invention]

[0008] The rubber that forms the rubber layer that covers the damping rubber member is made of butyl rubber, halogenated butyl rubber, etc., which have gas barrier properties. However, these rubbers have few double bonds and have weak adhesive strength with the steel material of the flange, so they tend to peel off from the flange under high strain, which can become the starting point of destruction.

[0009] The present invention has been made in consideration of the above circumstances, and has an object to provide a coating rubber composition capable of forming a coating rubber layer excellent in adhesive strength with a flange and in fracture durability (particularly in fracture durability under large strain deformation). Another object of the present invention is to provide a vibration energy absorbing unit using the coating rubber composition for a coating rubber layer. [Means for solving the problem]

[0010] The coated rubber composition of the present invention, which is able to solve the above-mentioned problems, is used to form a coated rubber layer that covers the exposed surface of a damping rubber member equipped in a vibration energy absorption unit, and is characterized in that it contains 15 parts by mass or more and 70 parts by mass or less of silica per 100 parts by mass of base rubber containing halogenated butyl rubber. Effect of the Invention

[0011] According to the present invention, a coating rubber composition capable of forming a coating rubber layer excellent in adhesive strength to a flange and in fracture durability (particularly in fracture durability under large strain deformation) can be obtained. According to the present invention, a vibration energy absorbing unit having a coating rubber layer excellent in adhesive strength to a flange and in fracture durability (particularly in fracture durability under large strain deformation) can be obtained. [Brief description of the drawings]

[0012] [Figure 1] 1 is a partially cutaway perspective view showing an example of an embodiment of a vibration energy absorbing unit of the present invention; [Diagram 2] FIG. 2 is an exploded perspective view showing a test specimen as a model of a vibration energy absorbing unit prepared for evaluating the fracture durability of the vibration energy absorbing unit using the coating rubber composition of the present invention. [Diagram 3] FIG. 2 is a diagram illustrating an outline of a testing machine for carrying out a test in which the test specimen is displaced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <Coating rubber composition> The coating rubber composition of the present invention is intended to form a coating rubber layer that covers the exposed surface of a damping rubber member provided in a vibration energy absorption unit, and is characterized by containing 15 parts by mass or more and 70 parts by mass or less of silica per 100 parts by mass of base rubber containing halogenated butyl rubber.

[0014] The mechanism by which the use of the coating rubber composition of the present invention enables the formation of a coating rubber layer having excellent adhesive strength to a flange and fracture durability (particularly fracture durability under large strain deformation) is not necessarily clear, but is thought to be as follows.

[0015] When the vibration energy absorbing unit incorporated in the structure is sheared to a high strain, the coating rubber layer covering the exposed surface of the damping rubber member is locally stretched to the limit, and becomes hardened. If this is repeated, the adhesive strength with the flange cannot be maintained, and the coating rubber layer peels off from the flange. Then, the breakage spreads from there, and the fracture durability decreases. The inventors have found that the above phenomenon is particularly likely to occur when a halogenated butyl rubber with a small number of double bonds is used as the rubber forming the coating rubber layer, and that by blending an appropriate amount of silica into the base rubber containing the halogenated butyl rubber, the coating rubber layer stretched to the limit can be plastically deformed before peeling off, and the adhesive strength can be maintained. The coating rubber layer formed from the coating rubber composition of the present invention has improved adhesive strength with the flange, and is excellent in fracture durability, especially against repeated deformation of high strain caused by multiple earthquakes.

[0016] (Base rubber) The coating rubber composition of the present invention contains a base rubber (hereinafter sometimes simply referred to as "base rubber") that contains a halogenated butyl rubber.

[0017] The halogenated butyl rubber may be a halogenated butyl rubber, which is a copolymer of isobutylene and a small amount of other monomers.

[0018] The other monomers generally include hydrocarbons having one or two carbon-carbon double bonds in one molecule, such as ethylene, propene, butene, hexene, styrene, alkylstyrene (such as 4-methylstyrene), isoprene, butadiene, or the like.

[0019] The butyl rubber is preferably a copolymer obtained by polymerizing isobutylene and a small amount of isoprene. The content of isobutylene in the copolymer is not particularly limited, but is preferably, for example, about 80 mol% to 99 mol%, particularly preferably about 90 mol% to 99 mol%.

[0020] Examples of halogenated butyl rubber include chlorinated butyl rubber, brominated butyl rubber, and brominated copolymers of isobutylene and p-methylstyrene. The halogenated butyl rubber is preferably chlorinated butyl rubber or brominated butyl rubber. The chlorinated butyl rubber or brominated butyl rubber is, for example, a rubber obtained by adding or substituting chlorine or bromine to the isoprene structure portion of butyl rubber, specifically, to the double bond and / or the carbon atom adjacent to the double bond.

[0021] The halogen content in the halogenated butyl rubber is preferably 0.5% by mass or more, preferably 1% by mass or more, more preferably 1.5% by mass or more, and is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.

[0022] A specific example of the chlorinated butyl rubber is CHLOROBUTYL 1066 (stabilizer: NS, halogen content: 1.26%, Mooney viscosity: 38ML) manufactured by Japan Butyl Co., Ltd. 1+8 (125° C., specific gravity: 0.92); LANXESS X_BUTYL CB1240 manufactured by LANXESS Corporation, and the like.

[0023] A specific example of the brominated butyl rubber is BROMOBUTYL2255 (stabilizer: NS, halogen content: 2.0%, Mooney viscosity: 46ML) manufactured by Japan Butyl Co., Ltd. 1+8 (125° C., specific gravity: 0.93); LANXESS X_BUTYL BBX2 manufactured by LANXESS Corporation, and the like.

[0024] In the present invention, it is preferable to use brominated butyl rubber as the halogenated butyl rubber. By using brominated butyl rubber, for example, when a vibration energy absorbing unit is produced by simultaneously vulcanizing a coating rubber layer made of the coating rubber composition of the present invention and an internal damping rubber member as described below, the vulcanization speeds of the damping rubber member and the coating rubber layer can be well matched.

[0025] The base rubber may further contain other rubbers in addition to the halogenated butyl rubber. Examples of the other rubbers include non-halogenated butyl rubber, natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, chloroprene rubber, and other diene rubbers; and ethylene-propylene-diene rubber (EPDM) and other non-diene rubbers. These may be used alone or in combination of two or more.

[0026] The content of the halogenated butyl rubber in the base rubber is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 80% by mass or more. In a preferred embodiment, the base rubber substantially contains only halogenated butyl rubber. By making the content of the halogenated butyl rubber in the base rubber 50% by mass or more, the gas barrier properties of the coating rubber layer are more excellent and the effects of the present invention are more effectively exhibited.

[0027] (silica) The coating rubber composition of the present invention contains silica, for example, synthetic silica obtained mainly by chemically reacting silica sand as a raw material.

[0028] The silica may be either wet-process silica or dry-process silica, which are classified according to the manufacturing method. Wet-process silica is classified into precipitated silica (wet silica) and gel-process silica (silica gel) according to the difference in reaction conditions, but it is preferable to use precipitated silica (wet silica), which has relatively large primary particles and a soft aggregate structure. Precipitated silica (wet silica) has better dispersibility in rubber. It is considered that the use of precipitated silica (wet silica) further enhances the effect of silica in improving adhesive strength.

[0029] Specific examples of the silica include commercially available products such as the Nipsil (registered trademark) series (eg, Nipsil VN3) manufactured by Tosoh Silica Corporation.

[0030] The BET specific surface area of ​​the silica is preferably 100 m 2 / g or more, more preferably 150m 2 / g or more, more preferably 200m 2 / g or more, and 2 / g or less is preferable, and 300m 2 / g or less is preferable. The BET specific surface area is a value measured by a gas phase adsorption method using nitrogen gas as an adsorption gas. The BET specific surface area of ​​silica is measured based on JIS-K6430:2008.

[0031] The amount of silica, relative to 100 parts by mass of the base rubber, is preferably at least 15 parts by mass, more preferably at least 20 parts by mass, and even more preferably at least 25 parts by mass, and is preferably at most 70 parts by mass, more preferably at most 60 parts by mass, and even more preferably at most 50 parts by mass. If the amount of silica is 15 parts by mass or more, the effect of improving the adhesive strength due to the silica is exerted, and if it is 70 parts by mass or less, the processability is good.

[0032] (Carbon Black) The coated rubber composition of the present invention preferably further contains carbon black as a rubber reinforcing filler.

[0033] The type of carbon black is not particularly limited. Examples of the carbon black include furnace carbon black such as SAF (Super Abrasion Furnace Black), ISAF (Intermediate Super Abrasion Furnace Black), IISAF (Intermediate ISAF), HAF (High Abrasion Furnace Black), MAF (Medium Abrasion Furnace Black), FEF (Fast Extruding Furnace Black), SRF (Semi-Reinforcing Furnace Black), GPF (General Purpose Furnace Black), FF (Fine Furnace Black), and CF (Conductive Furnace Black); thermal carbon black such as FT (Fine Thermal Black) and MT (Medium Thermal Black); channel carbon black such as EPC (Easy Processing Channel Black) and MPC (Medium Processing Channel Black); and acetylene black. The carbon black may be used alone or in combination of two or more.

[0034] Specific examples of the carbon black include commercially available products such as Diablack (registered trademark) series manufactured by Mitsubishi Chemical Corporation and Seest (registered trademark) series manufactured by Tokai Carbon Co., Ltd.

[0035] The carbon black content, relative to 100 parts by mass of the base rubber, is preferably 0 part by mass or more, more preferably 5 parts by mass or more, and even more preferably 10 parts by mass or more, and is preferably 60 parts by mass or less, more preferably 55 parts by mass or less, and even more preferably 50 parts by mass or less. If the carbon black content is within the above range, the reinforcing effect of the carbon black can be obtained, while improving processability.

[0036] The nitrogen adsorption specific surface area of ​​the carbon black is 20 m 2 / g or more is preferable, and 30m 2 / g or more is more preferable, and 50m 2 / g or more is more preferable, and 200m 2 / g or less is preferable, and 160m 2 / g or less is more preferable, and 140m 2 The nitrogen adsorption specific surface area can be measured, for example, in accordance with JIS K6217-2:2001.

[0037] (Vulcanizing component) The coating rubber composition of the present invention preferably contains vulcanizing components such as a vulcanizing agent, a vulcanization accelerator, and a vulcanization aid.

[0038] [Vulcanizing agent] As the vulcanizing agent, it is preferable to use a sulfur-based vulcanizing agent. Examples of the sulfur-based vulcanizing agent include powdered sulfur, oil-treated powdered sulfur, precipitated sulfur, colloidal sulfur, and dispersible sulfur. These sulfur-based vulcanizing agents may be used alone or in combination of two or more.

[0039] Specific examples of the vulcanizing agent include commercially available products such as 5% oil-treated powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd.

[0040] The content of the vulcanizing agent is preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, and preferably 3.0 parts by mass or less, and more preferably 2.0 parts by mass or less, per 100 parts by mass of the base rubber. When oil-treated powdered sulfur, dispersible sulfur, or the like is used as the vulcanizing agent, the content refers to the content of sulfur itself as an active ingredient contained therein.

[0041] [Vulcanization accelerator] Examples of the vulcanization accelerator include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole and 2,2'-dibenzothiazolyl disulfide; dithiocarbamate-based accelerators such as zinc dimethyldithiocarbamate; thiuram-based vulcanization accelerators such as tetramethylthiuram disulfide (TMTD), tetrabenzylthiuram disulfide (TBzTD), and tetrakis(2-ethylhexyl)thiuram disulfide (TOT-N); sulfenamide-based vulcanization accelerators such as N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N-tert-butyl-2-benzothiazolylsulfenamide (TBBS), N-oxyethylene-2-benzothiazolesulfenamide, and N,N'-diisopropyl-2-benzothiazolesulfenamide; and guanidine-based vulcanization accelerators such as diphenylguanidine, di-orthotolylguanidine, and orthotolylbiguanidine. These vulcanization accelerators may be used alone or in combination of two or more kinds.

[0042] Specific examples of the vulcanization accelerator include the Noccelaer (registered trademark) series (for example, Noccelaer DM) manufactured by Ouchi Shinko Chemical Co., Ltd.

[0043] The content of the vulcanization accelerator per 100 parts by mass of the base rubber is preferably 0.5 parts by mass or more, and more preferably 0.8 parts by mass or more, and is preferably 3.0 parts by mass or less, and more preferably 2.0 parts by mass or less.

[0044] [Vulcanization aid] Examples of the vulcanization aid include metal compounds such as zinc oxide and magnesium oxide, and fatty acids such as stearic acid, oleic acid, and cottonseed fatty acid. The vulcanization aid may be surface-treated to improve dispersibility in rubber. These vulcanization aids may be used alone or in combination of two or more.

[0045] Specific examples of the vulcanization aid include commercially available products such as zinc oxide type 2 manufactured by Mitsui Mining & Smelting Co., Ltd., Magsarat (registered trademark) series (surface-treated magnesium oxide) manufactured by Kyowa Chemical Industry Co., Ltd., and Tsubaki (stearic acid) manufactured by NOF Corporation.

[0046] The amount of the vulcanization aid per 100 parts by mass of the base rubber is preferably 1 part by mass or more, and more preferably 2 parts by mass or more, and is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

[0047] It is also preferable to use a metal compound and a fatty acid in combination as a vulcanization aid. In this case, the mass ratio of the metal compound to the fatty acid (metal compound / fatty acid) is preferably 0.5 or more, more preferably 1 or more, and is preferably 5 or less, more preferably 3 or less.

[0048] (Other Ingredients) In addition to the above-mentioned components, the coating rubber composition of the present invention may further contain various additives that can be used in coating rubber compositions, such as tackifiers, softeners, and antioxidants, which may be appropriately selected within the scope not impairing the object of the present invention.

[0049] [Tackifier] Examples of the tackifier include petroleum-based resins such as aliphatic petroleum-based resins, aromatic petroleum-based resins, aromatic modified aliphatic petroleum-based resins, etc. These tackifiers may be used alone or in combination of two or more kinds.

[0050] Specific examples of the petroleum-based resin include commercially available products such as Quinton (registered trademark) series (eg, Quinton A100) manufactured by Zeon Corporation.

[0051] The amount of the tackifier is preferably 1 part by mass or more, and more preferably 2 parts by mass or more, per 100 parts by mass of the base rubber, and is preferably 10 parts by mass or less, and more preferably 8 parts by mass or less.

[0052] [Softener] Examples of the softener include various oils. These softeners may be used alone or in combination of two or more kinds.

[0053] Specific examples of the oil include commercially available products such as Diana (registered trademark) Process Oil PW, NH, NP, NS, NR, NM, AC, and AH manufactured by Idemitsu Kosan Co., Ltd.

[0054] The amount of the softener per 100 parts by weight of the base rubber is preferably at least 5 parts by weight, and more preferably at least 10 parts by weight, and is preferably at most 50 parts by weight, and even more preferably at most 40 parts by weight.

[0055] The coating rubber composition of the present invention can be prepared, for example, by kneading the base rubber, silica, and, if necessary, the carbon black, vulcanization components, and other components. The kneading method is not particularly limited, and may be performed using a known kneading machine such as an internal kneader, a kneading roll, a Banbury mixer, or a kneader.

[0056] The coating rubber composition of the present invention is suitably used as a coating rubber composition for forming a coating rubber layer that covers the exposed surface (i.e., the surface that is not in contact with a pair of flanges) of a damping rubber member provided in a vibration energy absorption unit.

[0057] <Vibration energy absorption unit> The present invention includes a vibration energy absorbing unit including a pair of flanges and a damping rubber member interposed between the flanges, characterized in that the exposed surface of the damping rubber member is covered with a coating rubber layer formed from the coating rubber composition of the present invention. The vibration energy can be vibration energy caused by an earthquake, and the vibration energy absorbing unit is suitably used in a seismic isolation device or a vibration control device.

[0058] In the vibration energy absorption unit of the present invention, it is sufficient that at least a part of the surface where the damping rubber member is exposed is covered with a coating rubber layer formed from the coating rubber composition of the present invention, and it is preferable that the entire surface where the damping rubber member is exposed is covered with a coating rubber layer formed from the coating rubber composition of the present invention. This is because the increased coverage by the coating rubber layer suppresses damage and deterioration over time of the damping rubber member.

[0059] An example of the vibration energy absorbing unit of the present invention is shown in Fig. 1. Fig. 1 is a partially cutaway perspective view showing an example of an embodiment of the vibration energy absorbing unit of the present invention. The vibration energy absorbing unit 10 includes a pair of flanges 20, 20' made of, for example, steel plates, and a damping rubber member 30 made of, for example, diene-based damping rubber, which is interposed between the flanges 20, 20'.

[0060] The flanges 20, 20' are each formed in a rectangular plate shape in plan view. The damping rubber member 30 is formed in a rectangular, thick plate shape smaller than the flanges 20, 20'. The material of the flanges 20, 20' is not particularly limited, but may be, for example, steel SS490. The flanges 20, 20' and the damping rubber member 30 are integrated with each other, for example, by vulcanization adhesion, in a state in which the four sides of each are parallel to each other and the flanges 20, 20' protrude outward over the entire circumference of the damping rubber member 30.

[0061] The exposed surface (outer peripheral surface) of the damping rubber member 30 (i.e., the surface not in contact with the flanges 20, 20') is covered over its entire surface with a coating rubber layer 40 formed from the coating rubber composition of the present invention. This prevents the damping rubber member 30 from being damaged or deteriorating over time.

[0062] The covering rubber layer 40 is integrated with the damping rubber member 30 and the flanges 20, 20' by, for example, vulcanization adhesion.

[0063] Specifically, the vibration energy absorbing unit 10 is manufactured, for example, in the following procedure. That is, the pre-vulcanized damping rubber member 30 is set between a pair of flanges 20, 20'. The surface (outer peripheral surface) of the damping rubber member 30 that is not in contact with the flanges 20, 20' is covered with a pre-vulcanized coating rubber layer 40 made of the coating rubber composition of the present invention. A vulcanization adhesive, for example, is interposed between each of the above-mentioned parts. Note that the surface (outer peripheral surface) of the pre-vulcanized damping rubber member 30 that is not in contact with the flanges 20, 20' may be covered with the pre-vulcanized coating rubber layer 40 made of the coating rubber composition of the present invention, and then the damping rubber member 30 may be set between the pair of flanges 20, 20'.

[0064] Thereafter, the entire assembly is vulcanized, whereby the damping rubber member 30 and the covering rubber layer 40 are vulcanized, and the flanges 20, 20', the damping rubber member 30 and the covering rubber layer 40 are integrated together by vulcanization adhesion, thereby producing the vibration energy absorbing unit 10. The configuration of the vibration energy absorption unit of the present invention is not limited to the example shown in Fig. 1. For example, the damping rubber member 30 may be formed into a thick disk shape. The damping rubber member 30 may also be formed into a multi-layer structure in which rubber layers made of damping rubber and constraining layers made of steel plates or the like are alternately laminated. EXAMPLES

[0065] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples, and all modifications and embodiments that do not deviate from the spirit of the present invention are included within the scope of the present invention.

[0066] [Evaluation method] <90° peel strength> The 90° peel adhesion strength was evaluated according to the method of adhesives-peel adhesion strength test method Part 1: 90° peel JIS-K6854-1. The 90° peel adhesion strength of the coating rubber composition No. 1 was set as 100%, and the peel strength of the coating rubber composition prepared in each example in Table 1 was expressed as an index. Those with a 90° peel adhesion strength of 105% or more were evaluated as "○", and those with a peel adhesion strength of less than 105% were evaluated as "×".

[0067] <Damage resistance> (Preparation of test specimen) As shown in FIG. 2, the damping rubber composition was extruded into a sheet and punched into a rectangle (8 mm thick x 36 mm long x 36 mm wide) to produce a member 21 made of the damping rubber composition. The sides of the damping rubber member 21 were wrapped with the coating rubber composition rolled into a sheet to form a coating layer 23 made of the coating rubber composition so as to have a thickness of 8 mm and a width of 2 mm, and a flat plate 1 was produced. Next, rectangular flat flanges (steel plates) 2 measuring 6 mm thick x 44 mm long x 44 mm wide were laminated on both the front and back sides of the flat plate 1 via a vulcanizing adhesive to produce a laminate 25. The laminate 25 was then heated to 150° C. while being pressurized in the lamination direction to vulcanize the damping rubber composition forming the damping rubber member and the coating rubber composition forming the coating rubber layer, and the steel plate, the damping rubber member, and the coating rubber layer were vulcanized and bonded to each other to produce a test specimen 3 for evaluating fracture durability as a model of a vibration energy absorption unit.

[0068] The damping rubber composition used was a composition containing natural rubber, silica, coumarone resin, dicyclopentadiene resin, liquid polyisoprene rubber, a silylation agent, and carbon black.

[0069] (Displacement test) As shown in Fig. 3(a), two test specimens 3 were prepared, and the two test specimens 3 were fixed to one central fixture 4 via one of the steel plates 2 with bolts, and one left and right fixture 5 was fixed to the other steel plate 2 of each of the test specimens 3 with bolts. Next, the central fixture 4 was fixed to an upper fixed arm 6 of a testing machine (not shown) via a joint 7 with bolts, and the two left and right fixtures 5 were fixed to a lower movable platen 8 of the testing machine with bolts via joints 9. Both test specimens 3 were fixed as described above with the two parallel sides of the flat plate 1 aligned parallel to the displacement direction described below. Next, in an environment at 20° C., the following operations (I) and (II) were counted as one cycle, and the flat plate 1 was repeatedly strained and deformed by a large deformation of 300%. That is, the maximum displacement in each cycle was set so that the amount of deviation of the two steel plates 2 sandwiching the flat plate 1 in the direction perpendicular to the thickness direction (stacking direction) of the flat plate 1 was 300% of the thickness of the flat plate 1. (I): The movable platen 8 is displaced so as to be pushed upward toward the fixed arm 6 as shown by the white arrow in Figure 3(a), causing the flat plate 1 to be distorted and deformed in a direction perpendicular to the thickness direction (stacking direction) as shown in Figure 3(b). (II): From the above state, the movable platen 8 is then displaced so as to be pulled down in the direction opposite to the direction of the fixed arm 6, as indicated by the outlined arrow in FIG. 3(b), to return it to the state shown in FIG. 3(a).

[0070] (Evaluation of Destructive Durability) The number of cycles until the coating rubber layer of specimen 3 was broken was recorded. The number of cycles until the specimen using coating rubber composition No. 1 was broken was taken as 100%, and the values ​​for the specimens using the coating rubber compositions prepared in each example in Table 1 were expressed as an index. Those that were 105% or more were evaluated as "○", and those that were less than 105% were evaluated as "×".

[0071] <Overall Judgment> If the evaluation results for 90° peel adhesion strength and fracture durability were all "good", the overall judgment was "pass (good)", and if either the evaluation result for 90° peel adhesion strength or fracture durability was "bad", the overall judgment was "fail (bad)".

[0072] The components shown in Table 1 were kneaded together using an internal kneader to prepare a coating rubber composition. [Table 1]

[0073] The components in Table 1 are as follows. Base rubber: Brominated butyl rubber Exxon (registered trademark) Bromobutyl 2255 manufactured by ExxonMobil Chemical Silica: Evonik ULTRASIL VN3GR (BET specific surface area 180 m 2 / g) Silica: Nipsil (registered trademark) KQ (BET specific surface area 240 m) manufactured by Tosoh Silica Corporation 2 / g) Carbon black (GPF grade): Asahi Carbon Co., Ltd. Asahi #55 (nitrogen adsorption specific surface area: 26 m 2 / g) Vulcanizing agent: 5% oil-treated powdered sulfur manufactured by Tsurumi Chemical Industry Co., Ltd. Vulcanization accelerator: Noccela (registered trademark) DM (2,2'-dibenzothiazolyl disulfide) manufactured by Ouchi Shinko Chemical Co., Ltd. Stearic acid: Tsubaki made by NOF Corporation Zinc oxide: Two types of zinc oxide manufactured by Mitsui Mining & Smelting Co., Ltd. Magnesium oxide: Kyowa Chemical Industry Co., Ltd.'s Magsarat (registered trademark) 150 Petroleum-based resin: Arakawa Chemical Company's Tamanol N510 Softener: Diana (registered trademark) Process Oil PW-90 manufactured by Idemitsu Kosan Co., Ltd.

[0074] As is clear from the results in Table 1, the coating rubber layer is formed to cover the exposed surface of the damping rubber member equipped in the vibration energy absorption unit, and by using the coating rubber composition of the present invention containing 15 parts by mass or more and 50 parts by mass or less of silica per 100 parts by mass of base rubber containing halogenated butyl rubber, a coating rubber layer that has excellent adhesive strength with the plungee and fracture resistance under high strain deformation is formed. [Explanation of symbols]

[0075] 10: vibration energy absorption unit, 20, 20': flange, 30: damping rubber member, 40: coating rubber layer, 1: flat plate, 2: steel plate, 3: test specimen, 4: central fixing jig, 5: left and right fixing jig, 6: fixed arm, 7: joint, 8: movable platen, 9: joint

[0076] A preferred embodiment (1) of the present invention is a coating rubber composition for forming a coating rubber layer that covers an exposed surface of a damping rubber member provided in a vibration energy absorption unit, and is characterized by containing 15 parts by mass or more and 70 parts by mass or less of silica per 100 parts by mass of a base rubber containing halogenated butyl rubber.

[0077] A preferred embodiment (2) of the present invention is the coating rubber composition according to the embodiment (1), wherein the halogenated butyl rubber is a brominated butyl rubber and / or a chlorinated butyl rubber.

[0078] A preferred embodiment (3) of the present invention is the coating rubber composition according to embodiment (1) or (2), wherein the content of the halogenated butyl rubber in the base rubber is 50 mass % or more.

[0079] In a preferred embodiment (4) of the present invention, the BET specific surface area of ​​the silica is 50 m 2 / g or more, 350m 2 / g or less of the coating rubber composition according to any one of the embodiments (1) to (3).

[0080] A preferred embodiment (5) of the present invention is a vibration energy absorption unit including a damping rubber member, the exposed surface of the damping rubber member being covered with a coating rubber layer formed from the coating rubber composition of any one of the embodiments (1) to (4).

Claims

1. A coating rubber composition for forming a coating rubber layer that covers the exposed surface of a damping rubber member provided in a vibration energy absorption unit, the coating rubber composition comprising: 15 parts by mass or more and 70 parts by mass or less of silica per 100 parts by mass of a base rubber containing halogenated butyl rubber.

2. 2. The coating rubber composition according to claim 1, wherein the halogenated butyl rubber is a brominated butyl rubber and / or a chlorinated butyl rubber.

3. The coating rubber composition according to claim 1, wherein the content of the halogenated butyl rubber in the base rubber is 50% by mass or more.

4. The BET specific surface area of ​​the silica is 50 m ２ / g or more, 350m ２ The coating rubber composition according to claim 1, wherein the elastic modulus is 0.1 / g or less.

5. A vibration energy absorbing unit comprising a damping rubber member, the vibration energy absorbing unit being characterized in that an exposed surface of the damping rubber member is covered with a coating rubber layer formed from the coating rubber composition according to any one of claims 1 to 4.

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