CA2892484A1 - Cold-resistant rubber composition - Google Patents
Cold-resistant rubber composition Download PDFInfo
- Publication number
- CA2892484A1 CA2892484A1 CA2892484A CA2892484A CA2892484A1 CA 2892484 A1 CA2892484 A1 CA 2892484A1 CA 2892484 A CA2892484 A CA 2892484A CA 2892484 A CA2892484 A CA 2892484A CA 2892484 A1 CA2892484 A1 CA 2892484A1
- Authority
- CA
- Canada
- Prior art keywords
- rubber
- mass
- parts
- cold
- content
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L7/00—Compositions of natural rubber
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L11/00—Compositions of homopolymers or copolymers of chloroprene
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Springs (AREA)
- Fluid-Damping Devices (AREA)
Abstract
Provided is a rubber composition that is suitable for use in an air suspension for vehicles used in cold climates, said rubber composition exhibiting superior ozone resistance (as demonstrated by a dynamic ozone strain test) and cold resistance. Specifically provided is a cold-resistant rubber composition that includes a butadiene rubber, a chloroprene rubber, and a natural rubber or a rubber obtained by partially substituting a natural rubber with at least one specific rubber selected from the group consisting of styrene-butadiene rubbers and nitrile rubbers, wherein, with respect to a total of 100 parts by mass of the rubbers, the content of the butadiene rubber is 10-35 parts by mass, the content of the chloroprene rubber is 50-75 parts by mass, and the content of the natural rubber or the total content of the natural rubber and the specific rubber(s) is 10-35 parts by mass, and in cases when the specific rubber is present, the content of the specific rubber is preferably 10-60 mass% of the total content of the natural rubber and the specific rubber. Also provided is an air suspension for railway vehicles which uses the cold-resistant resin composition.
Description
DESCRIPTION
Title of Invention COLD-RESISTANT RUBBER COMPOSITION
Technical Field [0001]
The present invention relates to a rubber composition which is used in air springs for railway vehicle use, in particular, diaphragm portions of the air springs and the like, and which has excellent cold resistance that can endure use in cold climates, excellent ozone resistance, and excellent tackiness and adhesiveness at rubber-rubber joints.
Background Art
Title of Invention COLD-RESISTANT RUBBER COMPOSITION
Technical Field [0001]
The present invention relates to a rubber composition which is used in air springs for railway vehicle use, in particular, diaphragm portions of the air springs and the like, and which has excellent cold resistance that can endure use in cold climates, excellent ozone resistance, and excellent tackiness and adhesiveness at rubber-rubber joints.
Background Art
[0002]
In railway vehicles and the like, air springs are used to reduce vibration or the like applied from wheels to vehicles, making it possible to provide a comfortable ride. An air spring for railway vehicle use has, for example, a structure shown in Figs. 1 to 4 of Patent Literature 1, and includes an inner cylinder (lower plate) composed of rubber, an outer cylinder (upper plate), a diaphragm portion which seals a space between the inner and outer cylinders, and laminated rubber (stopper rubber) which is provided to reduce deterioration of a comfortable ride during deflation. The diaphragm portion is formed by bonding together a plurality of rubber sheets and reinforced cords (rubber sheets reinforced with fiber cords) and confines compressed air therein. In the air spring, the diaphragm portion mainly has a shock-absorbing function and reduces vibration applied to the vehicle.
In railway vehicles and the like, air springs are used to reduce vibration or the like applied from wheels to vehicles, making it possible to provide a comfortable ride. An air spring for railway vehicle use has, for example, a structure shown in Figs. 1 to 4 of Patent Literature 1, and includes an inner cylinder (lower plate) composed of rubber, an outer cylinder (upper plate), a diaphragm portion which seals a space between the inner and outer cylinders, and laminated rubber (stopper rubber) which is provided to reduce deterioration of a comfortable ride during deflation. The diaphragm portion is formed by bonding together a plurality of rubber sheets and reinforced cords (rubber sheets reinforced with fiber cords) and confines compressed air therein. In the air spring, the diaphragm portion mainly has a shock-absorbing function and reduces vibration applied to the vehicle.
[0003]
Railway vehicles may be used in cold climates in some cases. In such cases, air springs are desired to have excellent cold resistance that can endure use in cold climates, for example, a characteristic in which a decrease in rubber elasticity is small even under low temperatures, and cracks and the like do not occur.
Railway vehicles may be used in cold climates in some cases. In such cases, air springs are desired to have excellent cold resistance that can endure use in cold climates, for example, a characteristic in which a decrease in rubber elasticity is small even under low temperatures, and cracks and the like do not occur.
[0004]
Patent Literature 2 discloses a cold-resistant rubber, as a cold-resistant shaped rubber (packing, gasket, seal, or the like) having satisfactory mechanical strength even under low temperatures, which is obtained by using, as starting materials, 100 parts by weight of styrene-butadiene rubber (SBR), 30 to 50 parts by weight of carbon black having an iodine adsorption number of 80 to 130 mg/g, 10 to 30 parts by weight of naphthene-based process oil, 1 to 2 parts by weight of sulfur, and a vulcanization accelerator (Claim 1). It is described therein that although it is difficult to achieve both cold resistance and mechanical strength using SBR alone, by using carbon black having an iodine adsorption number in the range described above, and by using, as the vulcanization accelerator, a delayed-action accelerator, such as a sulfenamide-based accelerator, cold resistance can be improved without decreasing mechanical strength. It is described that natural rubber (NR), butadiene rubber (BR), chloroprene rubber (CR), and the like may be further compounded therewith.
Patent Literature 2 discloses a cold-resistant rubber, as a cold-resistant shaped rubber (packing, gasket, seal, or the like) having satisfactory mechanical strength even under low temperatures, which is obtained by using, as starting materials, 100 parts by weight of styrene-butadiene rubber (SBR), 30 to 50 parts by weight of carbon black having an iodine adsorption number of 80 to 130 mg/g, 10 to 30 parts by weight of naphthene-based process oil, 1 to 2 parts by weight of sulfur, and a vulcanization accelerator (Claim 1). It is described therein that although it is difficult to achieve both cold resistance and mechanical strength using SBR alone, by using carbon black having an iodine adsorption number in the range described above, and by using, as the vulcanization accelerator, a delayed-action accelerator, such as a sulfenamide-based accelerator, cold resistance can be improved without decreasing mechanical strength. It is described that natural rubber (NR), butadiene rubber (BR), chloroprene rubber (CR), and the like may be further compounded therewith.
[0005]
Examples of a rubber composition for air springs having excellent cold resistance include NR/polybutadiene rubber (BR) mixtures (mixing ratio: NR BR). Patent Literature 3 discloses a rubber composition obtained by incorporating a predetermined amount of ethylene-a-olefin-diene copolymer rubber (EPDM) into a rubber composition for air springs containing NR and BR as main rubber components, and Patent Literature 4 discloses a rubber composition obtained by incorporating a predetermined amount of polychloroprene rubber (CR) into a rubber composition for air springs containing NR and BR as main rubber components. These rubber compositions each contain a NR/BR
mixture (mixing ratio: NR BR) having excellent cold resistance, as a base, with which a predetermined amount of EPDM or CR is compounded in order to impart ozone resistance.
It is stated that this makes it possible to obtain a rubber composition for air springs having excellent cold resistance and excellent ozone resistance.
Citation List Patent Literatures
Examples of a rubber composition for air springs having excellent cold resistance include NR/polybutadiene rubber (BR) mixtures (mixing ratio: NR BR). Patent Literature 3 discloses a rubber composition obtained by incorporating a predetermined amount of ethylene-a-olefin-diene copolymer rubber (EPDM) into a rubber composition for air springs containing NR and BR as main rubber components, and Patent Literature 4 discloses a rubber composition obtained by incorporating a predetermined amount of polychloroprene rubber (CR) into a rubber composition for air springs containing NR and BR as main rubber components. These rubber compositions each contain a NR/BR
mixture (mixing ratio: NR BR) having excellent cold resistance, as a base, with which a predetermined amount of EPDM or CR is compounded in order to impart ozone resistance.
It is stated that this makes it possible to obtain a rubber composition for air springs having excellent cold resistance and excellent ozone resistance.
Citation List Patent Literatures
[0006]
PTL 1: Japanese Patent No. 3866520 PTL 2: Japanese Unexamined Patent Application Publication No. 2003-119321 PTL 3: Japanese Unexamined Patent Application Publication No. 2009-215541 PTL 4: Japanese Unexamined Patent Application Publication No. 2010-13504 Summary of Invention Technical Problem
PTL 1: Japanese Patent No. 3866520 PTL 2: Japanese Unexamined Patent Application Publication No. 2003-119321 PTL 3: Japanese Unexamined Patent Application Publication No. 2009-215541 PTL 4: Japanese Unexamined Patent Application Publication No. 2010-13504 Summary of Invention Technical Problem
[0007]
, However, in the rubber (compositions) disclosed in Patent Literatures 2 to 4, the ozone resistance measured in accordance with the dynamic ozone deterioration test (JIS
K6259) is insufficient, and an improvement in ozone resistance has been desired. In the dynamic ozone deterioration test, when the specimen is exposed to air containing ozone at a fixed concentration while being subjected to repeated strain, the occurrence of cracks in the rubber is evaluated. This evaluation is performed in an environment close to the actual use condition. (The ozone resistance test in Patent Literatures 3 and 4 is considered to be a static ozone deterioration test which does not necessarily correspond to the actual use condition.) Accordingly, the "ozone resistance" described hereafter refers to the dynamic ozone resistance. Furthermore, the simple term "cold resistance" is used to describe that a decrease in rubber elasticity is small and cracks and the like do not occur even under low temperatures, and specifically that the brittle temperature determined in accordance with JIS K6261 is low.
, However, in the rubber (compositions) disclosed in Patent Literatures 2 to 4, the ozone resistance measured in accordance with the dynamic ozone deterioration test (JIS
K6259) is insufficient, and an improvement in ozone resistance has been desired. In the dynamic ozone deterioration test, when the specimen is exposed to air containing ozone at a fixed concentration while being subjected to repeated strain, the occurrence of cracks in the rubber is evaluated. This evaluation is performed in an environment close to the actual use condition. (The ozone resistance test in Patent Literatures 3 and 4 is considered to be a static ozone deterioration test which does not necessarily correspond to the actual use condition.) Accordingly, the "ozone resistance" described hereafter refers to the dynamic ozone resistance. Furthermore, the simple term "cold resistance" is used to describe that a decrease in rubber elasticity is small and cracks and the like do not occur even under low temperatures, and specifically that the brittle temperature determined in accordance with JIS K6261 is low.
[0008]
A diaphragm portion of an air spring is formed by bonding together a plurality of rubber sheets and reinforced cords, followed by vulcanization. Accordingly, in order to prevent separation between the rubber sheets when the air spring is used, strong adhesion between vulcanized rubber sheets (rubber-rubber adhesion) is needed. In particular, under low temperatures, it is considered that stress becomes concentrated at rubber-rubber joints, which is likely to cause separation, and therefore, it is desired to strengthen rubber-rubber adhesion. Furthermore, in the process for manufacturing a diaphragm portion, prior to a vulcanization step, i.e., in a step in which unvulcanized rubber sheets are bonded together to form a predetermined shape, it is necessary to perform temporary fastening so that separation of the rubber sheets does not occur. Thus, excellent "tackiness"
(temporary adhesion) between rubber sheets in the unvulcanized state is also needed.
A diaphragm portion of an air spring is formed by bonding together a plurality of rubber sheets and reinforced cords, followed by vulcanization. Accordingly, in order to prevent separation between the rubber sheets when the air spring is used, strong adhesion between vulcanized rubber sheets (rubber-rubber adhesion) is needed. In particular, under low temperatures, it is considered that stress becomes concentrated at rubber-rubber joints, which is likely to cause separation, and therefore, it is desired to strengthen rubber-rubber adhesion. Furthermore, in the process for manufacturing a diaphragm portion, prior to a vulcanization step, i.e., in a step in which unvulcanized rubber sheets are bonded together to form a predetermined shape, it is necessary to perform temporary fastening so that separation of the rubber sheets does not occur. Thus, excellent "tackiness"
(temporary adhesion) between rubber sheets in the unvulcanized state is also needed.
[0009]
It is an object of the present invention to provide a rubber composition which can be suitably used in air springs for vehicle use used in cold climates and which has excellent ozone resistance (measured by the dynamic ozone deterioration test) and excellent cold resistance and which also has excellent rubber-rubber adhesion and tackiness.
Solution to Problem
It is an object of the present invention to provide a rubber composition which can be suitably used in air springs for vehicle use used in cold climates and which has excellent ozone resistance (measured by the dynamic ozone deterioration test) and excellent cold resistance and which also has excellent rubber-rubber adhesion and tackiness.
Solution to Problem
[0010]
According to a first embodiment of the present invention, a cold-resistant rubber composition contains butadiene rubber (BR), chloroprene rubber (CR), and natural rubber (NR), in which the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the content of the NR is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, and the NR.
According to a first embodiment of the present invention, a cold-resistant rubber composition contains butadiene rubber (BR), chloroprene rubber (CR), and natural rubber (NR), in which the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the content of the NR is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, and the NR.
[0011]
According to a second embodiment of the present invention, in the cold-resistant rubber composition according to the first embodiment of the present invention, part of the NR is replaced with at least one specific rubber selected from the group consisting of styrene-butadiene rubber (SBR) and nitrite rubber (acrylonitrile butadiene rubber: NBR).
According to the second embodiment of the present invention, the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the total content of the NR and the specific rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber, and the content of the specific rubber is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber.
Advantageous Effects of Invention
According to a second embodiment of the present invention, in the cold-resistant rubber composition according to the first embodiment of the present invention, part of the NR is replaced with at least one specific rubber selected from the group consisting of styrene-butadiene rubber (SBR) and nitrite rubber (acrylonitrile butadiene rubber: NBR).
According to the second embodiment of the present invention, the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the total content of the NR and the specific rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber, and the content of the specific rubber is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber.
Advantageous Effects of Invention
[0012]
According to the first embodiment of the present invention, there is provided a rubber composition which has excellent ozone resistance and excellent cold resistance, which has excellent rubber-rubber tackiness and rubber-rubber adhesion during the process of manufacturing air springs, and which can be suitably used for manufacturing air springs for vehicle use used in cold climates.
According to the first embodiment of the present invention, there is provided a rubber composition which has excellent ozone resistance and excellent cold resistance, which has excellent rubber-rubber tackiness and rubber-rubber adhesion during the process of manufacturing air springs, and which can be suitably used for manufacturing air springs for vehicle use used in cold climates.
[0013]
According to the second embodiment of the present invention, there is provided a rubber composition which has excellent ozone resistance and excellent cold resistance, and which has more excellent rubber-rubber adhesion (than the first embodiment).
Consequently, when the rubber composition is used for forming air springs, since it is possible to provide ozone resistance, cold resistance, excellent rubber-rubber tackiness, and stronger rubber-rubber adhesion that prevents separation between rubber sheets of a diaphragm which have been vulcanized, the rubber composition can be more suitably used for manufacturing air springs for vehicle use used in cold climates.
Description of Embodiments
According to the second embodiment of the present invention, there is provided a rubber composition which has excellent ozone resistance and excellent cold resistance, and which has more excellent rubber-rubber adhesion (than the first embodiment).
Consequently, when the rubber composition is used for forming air springs, since it is possible to provide ozone resistance, cold resistance, excellent rubber-rubber tackiness, and stronger rubber-rubber adhesion that prevents separation between rubber sheets of a diaphragm which have been vulcanized, the rubber composition can be more suitably used for manufacturing air springs for vehicle use used in cold climates.
Description of Embodiments
[0014]
Preferred embodiments for carrying out the first and second embodiments will be described below on the basis of specific examples and the like. However, the first and second embodiments of the present invention are not limited to the preferred embodiments and the specific examples, and it is intended that the scope of the present invention is determined by appended claims, and includes all variations of the equivalent meanings and ranges to the claims.
Preferred embodiments for carrying out the first and second embodiments will be described below on the basis of specific examples and the like. However, the first and second embodiments of the present invention are not limited to the preferred embodiments and the specific examples, and it is intended that the scope of the present invention is determined by appended claims, and includes all variations of the equivalent meanings and ranges to the claims.
[0015]
The present inventors have performed thorough studies, and as a result, have found that, in a rubber composition obtained by mixing BR, CR, and NR, by setting the CR as a main component, and setting the mixing ratios thereof to predetermined ranges, it is possible to obtain rubber having excellent ozone resistance and excellent cold resistance and having excellent rubber-rubber adhesion and rubber-rubber tackiness. Thus, the first embodiment of the present invention has been completed.
The present inventors have performed thorough studies, and as a result, have found that, in a rubber composition obtained by mixing BR, CR, and NR, by setting the CR as a main component, and setting the mixing ratios thereof to predetermined ranges, it is possible to obtain rubber having excellent ozone resistance and excellent cold resistance and having excellent rubber-rubber adhesion and rubber-rubber tackiness. Thus, the first embodiment of the present invention has been completed.
[0016]
The present inventors have further found that, in the rubber composition obtained by mixing BR, CR, and NR at predetermined mixing ratios, by replacing part of the NR
with SBR or NBR, the rubber-rubber adhesion is further improved while maintaining excellent ozone resistance, cold resistance, and rubber-rubber tackiness.
Thus, the second embodiment of the present invention has been completed.
The present inventors have further found that, in the rubber composition obtained by mixing BR, CR, and NR at predetermined mixing ratios, by replacing part of the NR
with SBR or NBR, the rubber-rubber adhesion is further improved while maintaining excellent ozone resistance, cold resistance, and rubber-rubber tackiness.
Thus, the second embodiment of the present invention has been completed.
[0017]
(1) Rubber composition according to first embodiment According to the first embodiment of the present invention, a cold-resistant rubber composition contains BR, CR, and NR, in which the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the content of the NR is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, and the NR.
(1) Rubber composition according to first embodiment According to the first embodiment of the present invention, a cold-resistant rubber composition contains BR, CR, and NR, in which the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the content of the NR is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, and the NR.
[0018]
The rubber composition according to the first embodiment of the present invention is characterized in that the BR, the CR, and the NR are mixed at the composition ratios in the ranges described above. This characteristic makes it possible to obtain excellent ozone resistance and cold resistance. Furthermore, the rubber composition has excellent tackiness. Consequently, when rubber-rubber bonding is performed, temporary fastening can be performed with sufficient tackiness, and therefore, good formability is achieved during the process of manufacturing air springs and the like.
The rubber composition according to the first embodiment of the present invention is characterized in that the BR, the CR, and the NR are mixed at the composition ratios in the ranges described above. This characteristic makes it possible to obtain excellent ozone resistance and cold resistance. Furthermore, the rubber composition has excellent tackiness. Consequently, when rubber-rubber bonding is performed, temporary fastening can be performed with sufficient tackiness, and therefore, good formability is achieved during the process of manufacturing air springs and the like.
[0019]
BR is a synthetic rubber obtained by polymerization of butadiene. Examples of BR include high-cis BR having a high cis-1,4 bond content, low-cis BR having a relatively low cis-1,4 bond content, a high-cis-syndiotactic polybutadiene compound, and the like, and any of these can be suitably used. In particular, high-cis BR having a very low glass transition temperature (Tg) of -95 C to -110 C is preferable.
BR is a synthetic rubber obtained by polymerization of butadiene. Examples of BR include high-cis BR having a high cis-1,4 bond content, low-cis BR having a relatively low cis-1,4 bond content, a high-cis-syndiotactic polybutadiene compound, and the like, and any of these can be suitably used. In particular, high-cis BR having a very low glass transition temperature (Tg) of -95 C to -110 C is preferable.
[0020]
As the high-cis BR, for example, those sold under trade names, such as JSR
(manufactured by JSR Corporation), Nipol BR1220 (manufactured by Zeon Corporation), and UBEPOL BR150 (manufactured by Ube Industries, Ltd.), can be used. As the low-cis BR, for example, those sold under trade names, such as Nipol BR1250H
(manufactured by Zeon Corporation) and Diene NF35R (manufactured by Asahi Kasei Corp.), can be used. As the high-cis-syndiotactic polybutadiene compound, for example, those sold under trade names, such as UBEPOL VCR412 (manufactured by Ube Industries, Ltd.), can be used.
As the high-cis BR, for example, those sold under trade names, such as JSR
(manufactured by JSR Corporation), Nipol BR1220 (manufactured by Zeon Corporation), and UBEPOL BR150 (manufactured by Ube Industries, Ltd.), can be used. As the low-cis BR, for example, those sold under trade names, such as Nipol BR1250H
(manufactured by Zeon Corporation) and Diene NF35R (manufactured by Asahi Kasei Corp.), can be used. As the high-cis-syndiotactic polybutadiene compound, for example, those sold under trade names, such as UBEPOL VCR412 (manufactured by Ube Industries, Ltd.), can be used.
[0021]
NR is made from rubber tree sap (latex) and is a rubber containing cis-polyisoprene as a main component. As the NR, RSS#1, RSS#3, or the like can be used, and the viscosity is appropriately adjusted by performing mastication when used. CR is a synthetic rubber obtained by polymerization of chloroprene and is sold under trade names, such as Neoprene (registered trademark). Examples of CR include mercaptan-modified CR, xanthate-modified CR, and sulfur-modified CR, and any of these can be used. In particular, those having slow crystallization speed are suitable for cold resistance. For example, those sold under trade names, such as Showa Denko Chloroprene WRT
(manufactured by Showa Denko K.K.), Skyprene B-5A (manufactured by Tosoh Corporation), and Denka Chloroprene S-40V (manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), can be used.
NR is made from rubber tree sap (latex) and is a rubber containing cis-polyisoprene as a main component. As the NR, RSS#1, RSS#3, or the like can be used, and the viscosity is appropriately adjusted by performing mastication when used. CR is a synthetic rubber obtained by polymerization of chloroprene and is sold under trade names, such as Neoprene (registered trademark). Examples of CR include mercaptan-modified CR, xanthate-modified CR, and sulfur-modified CR, and any of these can be used. In particular, those having slow crystallization speed are suitable for cold resistance. For example, those sold under trade names, such as Showa Denko Chloroprene WRT
(manufactured by Showa Denko K.K.), Skyprene B-5A (manufactured by Tosoh Corporation), and Denka Chloroprene S-40V (manufactured by Denki Kagaku Kogyo Kabushiki Kaisha), can be used.
[0022]
In the rubber composition according to the first embodiment, the composition ratio of the CR is in the range of 50 to 75 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the CR is less than 50 parts by mass, dynamic ozone resistance decreases, and it is unlikely to obtain excellent ozone resistance. On the other hand, when the composition ratio is more than 75 parts by mass, it is not possible to compound sufficient amounts of BR and NR, resulting in a decrease in cold resistance (an increase in the brittle temperature), and it is unlikely to obtain a brittle temperature (-60 C or lower) at the level that can be used in very cold climates at a temperature of -40 C to -50 C.
In the rubber composition according to the first embodiment, the composition ratio of the CR is in the range of 50 to 75 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the CR is less than 50 parts by mass, dynamic ozone resistance decreases, and it is unlikely to obtain excellent ozone resistance. On the other hand, when the composition ratio is more than 75 parts by mass, it is not possible to compound sufficient amounts of BR and NR, resulting in a decrease in cold resistance (an increase in the brittle temperature), and it is unlikely to obtain a brittle temperature (-60 C or lower) at the level that can be used in very cold climates at a temperature of -40 C to -50 C.
[0023]
In the rubber composition according to the first embodiment, the composition ratio of the BR is in the range of 10 to 35 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the BR is less than 10 parts by mass (even when the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases), and it is unlikely to obtain a brittle temperature of -60 C or lower. Rubber-rubber adhesion also decreases.
On the other hand, when the composition ratio is more than 35 parts by mass, it is necessary to decrease the composition ratio of the NR, resulting in a decrease in tackiness.
In the rubber composition according to the first embodiment, the composition ratio of the BR is in the range of 10 to 35 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the BR is less than 10 parts by mass (even when the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases), and it is unlikely to obtain a brittle temperature of -60 C or lower. Rubber-rubber adhesion also decreases.
On the other hand, when the composition ratio is more than 35 parts by mass, it is necessary to decrease the composition ratio of the NR, resulting in a decrease in tackiness.
[0024]
In the rubber composition according to the first embodiment, the composition ratio of the NR is in the range of 10 to 35 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the NR is less than 10 parts by mass, tackiness decreases. On the other hand, when the composition ratio is more than 35 parts by mass (it is necessary to decrease the composition ratio of the BR in the case where the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases) and it is unlikely to obtain a brittle temperature of -60 C or lower.
In the rubber composition according to the first embodiment, the composition ratio of the NR is in the range of 10 to 35 parts by mass relative to 100 parts by mass of the total of the BR, the CR, and the NR. When the composition ratio of the NR is less than 10 parts by mass, tackiness decreases. On the other hand, when the composition ratio is more than 35 parts by mass (it is necessary to decrease the composition ratio of the BR in the case where the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases) and it is unlikely to obtain a brittle temperature of -60 C or lower.
[0025]
(2) Rubber composition according to second embodiment According to the second embodiment of the present invention, in the cold-resistant rubber composition according to the first embodiment of the present invention, part of the NR is replaced with at least one specific rubber selected from the group consisting of SBR
and NBR. In the cold-resistant rubber composition according to the second embodiment of the present invention, the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the total content of the NR and the specific rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber, and the content of the specific rubber is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber.
(2) Rubber composition according to second embodiment According to the second embodiment of the present invention, in the cold-resistant rubber composition according to the first embodiment of the present invention, part of the NR is replaced with at least one specific rubber selected from the group consisting of SBR
and NBR. In the cold-resistant rubber composition according to the second embodiment of the present invention, the content of the BR is 10 to 35 parts by mass, the content of the CR is 50 to 75 parts by mass, and the total content of the NR and the specific rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber, and the content of the specific rubber is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber.
[0026]
As described above, a diaphragm portion of an air spring is formed by bonding together a plurality of rubber sheets and reinforced cords. Therefore, in order to prevent separation between the rubber sheets when the air spring is used, strong adhesion between rubber sheets (rubber-rubber adhesion) is needed. Since loads to the diaphragm may increase depending on the design and type of railway vehicles, the rubber-rubber adhesion is preferably as high as possible.
As described above, a diaphragm portion of an air spring is formed by bonding together a plurality of rubber sheets and reinforced cords. Therefore, in order to prevent separation between the rubber sheets when the air spring is used, strong adhesion between rubber sheets (rubber-rubber adhesion) is needed. Since loads to the diaphragm may increase depending on the design and type of railway vehicles, the rubber-rubber adhesion is preferably as high as possible.
[0027]
As the method for increasing the rubber-rubber adhesion, a method is conceivable in which the base rubber is changed to a material having good adhesion.
However, when a known material having good adhesion is used, it is not possible to obtain excellent cold resistance and tackiness. Furthermore, in a rubber composition composed of BR/CR/NR, by decreasing the content of NR and increasing the content of BR, adhesion can be improved while maintaining cold resistance and the like. However, in this case, tackiness decreases, and forming becomes difficult, which is a problem. Thus, no existing cold-resistant rubber can satisfy all of ozone resistance, tackiness, and rubber-rubber adhesion.
As the method for increasing the rubber-rubber adhesion, a method is conceivable in which the base rubber is changed to a material having good adhesion.
However, when a known material having good adhesion is used, it is not possible to obtain excellent cold resistance and tackiness. Furthermore, in a rubber composition composed of BR/CR/NR, by decreasing the content of NR and increasing the content of BR, adhesion can be improved while maintaining cold resistance and the like. However, in this case, tackiness decreases, and forming becomes difficult, which is a problem. Thus, no existing cold-resistant rubber can satisfy all of ozone resistance, tackiness, and rubber-rubber adhesion.
[0028]
The present inventors have found that, in the rubber composition according to the first embodiment, i.e., in the rubber compound having excellent cold resistance and ozone resistance, by replacing part of the NR with SBR or NBR, "rubber-rubber adhesion" can be further improved while maintaining "cold resistance", "ozone resistance", and "tackiness".
Thus, the second embodiment of the present invention has been completed.
The present inventors have found that, in the rubber composition according to the first embodiment, i.e., in the rubber compound having excellent cold resistance and ozone resistance, by replacing part of the NR with SBR or NBR, "rubber-rubber adhesion" can be further improved while maintaining "cold resistance", "ozone resistance", and "tackiness".
Thus, the second embodiment of the present invention has been completed.
[0029]
SBR is a copolymer of styrene and butadiene. There are two types of SBR, emulsion polymerization SBR (E-SBR) and solution polymerization SBR (S-SBR), and both can be suitably used. SBR having a low glass transition temperature (Tg) and containing a small amount of styrene bonded is more preferable. As the SBR, for example, those sold under trade names, such as Nipol 1502 (manufactured by Zeon Corporation), Nipol NS612 (manufactured by Zeon Corporation), and JSR 1500 (manufactured by JSR Corporation), can be used.
SBR is a copolymer of styrene and butadiene. There are two types of SBR, emulsion polymerization SBR (E-SBR) and solution polymerization SBR (S-SBR), and both can be suitably used. SBR having a low glass transition temperature (Tg) and containing a small amount of styrene bonded is more preferable. As the SBR, for example, those sold under trade names, such as Nipol 1502 (manufactured by Zeon Corporation), Nipol NS612 (manufactured by Zeon Corporation), and JSR 1500 (manufactured by JSR Corporation), can be used.
[0030]
NBR is a copolymer of acrylonitrile and butadiene, and NBR of any brand name can be suitably used. NBR having a low glass transition temperature (Tg) and containing a small amount of acrylonitrile bonded is more preferable. As the NBR, for example, those sold under trade names, such as Nipol 1043 (manufactured by Zeon Corporation), Nipol DN401LL (manufactured by Zeon Corporation), and JSR N250SL (manufactured by JSR Corporation), can be used.
NBR is a copolymer of acrylonitrile and butadiene, and NBR of any brand name can be suitably used. NBR having a low glass transition temperature (Tg) and containing a small amount of acrylonitrile bonded is more preferable. As the NBR, for example, those sold under trade names, such as Nipol 1043 (manufactured by Zeon Corporation), Nipol DN401LL (manufactured by Zeon Corporation), and JSR N250SL (manufactured by JSR Corporation), can be used.
[0031]
By replacing part of the NR constituting the rubber composition according to the first embodiment with SBR or NBR, "rubber-rubber adhesion" can be improved.
Although SBR and NBR have slightly lower tackiness than NR, if the percentage of the NR replaced with SBR or NBR is within a predetermined range, rubber-rubber adhesion can be improved while maintaining tackiness.
By replacing part of the NR constituting the rubber composition according to the first embodiment with SBR or NBR, "rubber-rubber adhesion" can be improved.
Although SBR and NBR have slightly lower tackiness than NR, if the percentage of the NR replaced with SBR or NBR is within a predetermined range, rubber-rubber adhesion can be improved while maintaining tackiness.
[0032]
In the rubber composition according to the second embodiment, the composition ratio of the CR is in the range of 50 to 75 parts by mass relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber. When the composition ratio of the CR is less than 50 parts by mass, dynamic ozone resistance decreases, and it is unlikely to obtain excellent ozone resistance. On the other hand, when the composition ratio is more than 75 parts by mass, it is not possible to compound sufficient amounts of BR and NR, resulting in a decrease in cold resistance (an increase in the brittle temperature), and it is unlikely to obtain a brittle temperature of -60 C or lower.
In the rubber composition according to the second embodiment, the composition ratio of the CR is in the range of 50 to 75 parts by mass relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber. When the composition ratio of the CR is less than 50 parts by mass, dynamic ozone resistance decreases, and it is unlikely to obtain excellent ozone resistance. On the other hand, when the composition ratio is more than 75 parts by mass, it is not possible to compound sufficient amounts of BR and NR, resulting in a decrease in cold resistance (an increase in the brittle temperature), and it is unlikely to obtain a brittle temperature of -60 C or lower.
[0033]
In the rubber composition according to the second embodiment, the composition ratio of the BR is in the range of 10 to 35 parts by mass, preferably in the range of 15 to 30 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber. When the composition ratio of the BR is less than 10 parts by mass (even when the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases), and it is unlikely to obtain a brittle temperature of -60 C or lower. On the other hand, when the composition ratio is more than 35 parts by mass, it is necessary to decrease the composition ratio of the total of the NR and the specific rubber, resulting in a decrease in tackiness.
In the rubber composition according to the second embodiment, the composition ratio of the BR is in the range of 10 to 35 parts by mass, preferably in the range of 15 to 30 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber. When the composition ratio of the BR is less than 10 parts by mass (even when the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases), and it is unlikely to obtain a brittle temperature of -60 C or lower. On the other hand, when the composition ratio is more than 35 parts by mass, it is necessary to decrease the composition ratio of the total of the NR and the specific rubber, resulting in a decrease in tackiness.
[0034]
In the rubber composition according to the second embodiment, the composition ratio of the total of the NR and the specific rubber is in the range of 10 to
In the rubber composition according to the second embodiment, the composition ratio of the total of the NR and the specific rubber is in the range of 10 to
35 parts by mass, preferably in the range of 15 to 30 parts by mass, relative to 100 parts by mass of the total of the BR, the CR, the NR, and the specific rubber. When the composition ratio of the total of the NR and the specific rubber is less than 10 parts by mass, tackiness decreases.
On the other hand, when the composition ratio of the total is more than 35 parts by mass (it is necessary to decrease the composition ratio of the BR in the case where the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases) and it is unlikely to obtain a brittle temperature of -60 C or lower.
[0035]
In the rubber composition according to the second embodiment, the content of the specific rubber (at least one rubber selected from the group consisting of SBR
and NBR) is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber. By replacing 10% to 60% by mass of the NR with the specific rubber, "rubber-rubber adhesion" can be further enhanced.
On the other hand, when the composition ratio of the total is more than 35 parts by mass (it is necessary to decrease the composition ratio of the BR in the case where the composition ratio of the CR is in the range of 50 to 75 parts by mass), cold resistance decreases (the brittle temperature increases) and it is unlikely to obtain a brittle temperature of -60 C or lower.
[0035]
In the rubber composition according to the second embodiment, the content of the specific rubber (at least one rubber selected from the group consisting of SBR
and NBR) is preferably 10% to 60% by mass relative to the total content of the NR and the specific rubber. By replacing 10% to 60% by mass of the NR with the specific rubber, "rubber-rubber adhesion" can be further enhanced.
[0036]
When the content of the specific rubber is less than the 10% by mass relative to the total content of the NR and the specific rubber, the effect of improving "rubber-rubber adhesion" is small. When the content of the specific rubber is more than 60%
by mass, tackiness of rubber may be insufficient in some cases.
When the content of the specific rubber is less than the 10% by mass relative to the total content of the NR and the specific rubber, the effect of improving "rubber-rubber adhesion" is small. When the content of the specific rubber is more than 60%
by mass, tackiness of rubber may be insufficient in some cases.
[0037]
(3) Additives and the like In each of the rubber compositions according to the first and second embodiments, in addition to the essential components described above, as necessary, other components, such as additives, may be compounded into the rubber composition within the range that does not impair the object of the present invention. Examples of the other components include a reinforcing filler such as carbon or silica, a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator aid, a retarder, an antioxidant, a plasticizer, a silane coupling agent, and the like. Furthermore, when an ester compound (DOP, DOA, or the like) having good low temperature fluidity is used as a plasticizer, the brittle temperature can be further decreased. However, in such a case, the plasticizer continuously bleeds or the plasticizer is extracted by water, a cleaning liquid, or the like, and as a result, the effect of improving cold resistance may be continuously decreased. Therefore, it is desirable to select rubber that exhibits satisfactory cold resistance even if such a plasticizer is not used.
(3) Additives and the like In each of the rubber compositions according to the first and second embodiments, in addition to the essential components described above, as necessary, other components, such as additives, may be compounded into the rubber composition within the range that does not impair the object of the present invention. Examples of the other components include a reinforcing filler such as carbon or silica, a vulcanizing agent, a vulcanization accelerator, a vulcanization accelerator aid, a retarder, an antioxidant, a plasticizer, a silane coupling agent, and the like. Furthermore, when an ester compound (DOP, DOA, or the like) having good low temperature fluidity is used as a plasticizer, the brittle temperature can be further decreased. However, in such a case, the plasticizer continuously bleeds or the plasticizer is extracted by water, a cleaning liquid, or the like, and as a result, the effect of improving cold resistance may be continuously decreased. Therefore, it is desirable to select rubber that exhibits satisfactory cold resistance even if such a plasticizer is not used.
[0038]
(4) Example of use of rubber compositions according to first and second embodiments The cold-resistant rubber composition according to the first embodiment has a low brittle temperature, excellent cold resistance, excellent ozone resistance, i.e., dynamic ozone resistance, and excellent rubber-rubber adhesiveness. Furthermore, since the cold-resistance rubber composition has excellent tackiness, temporary fastening can be performed with sufficient tackiness during bonding, and good formability is achieved during manufacturing of air springs.
Therefore, the cold-resistant rubber composition is suitable as a material constituting air springs for railway vehicle use used in cold climates.
Furthermore, the cold-resistant rubber according to the second embodiment has excellent cold resistance, ozone resistance, and tackiness and has more excellent "rubber-rubber adhesion" than the first embodiment. Therefore, the cold-resistant rubber composition is further suitable as a material constituting air springs for railway vehicle use used in cold climates.
(4) Example of use of rubber compositions according to first and second embodiments The cold-resistant rubber composition according to the first embodiment has a low brittle temperature, excellent cold resistance, excellent ozone resistance, i.e., dynamic ozone resistance, and excellent rubber-rubber adhesiveness. Furthermore, since the cold-resistance rubber composition has excellent tackiness, temporary fastening can be performed with sufficient tackiness during bonding, and good formability is achieved during manufacturing of air springs.
Therefore, the cold-resistant rubber composition is suitable as a material constituting air springs for railway vehicle use used in cold climates.
Furthermore, the cold-resistant rubber according to the second embodiment has excellent cold resistance, ozone resistance, and tackiness and has more excellent "rubber-rubber adhesion" than the first embodiment. Therefore, the cold-resistant rubber composition is further suitable as a material constituting air springs for railway vehicle use used in cold climates.
[0039]
Accordingly, there is provided, as a preferred embodiment of the present invention, an air spring for railway vehicle use which is formed using the rubber composition according to the first embodiment or the rubber composition according to the second embodiment.
EXAMPLES
Accordingly, there is provided, as a preferred embodiment of the present invention, an air spring for railway vehicle use which is formed using the rubber composition according to the first embodiment or the rubber composition according to the second embodiment.
EXAMPLES
[0040]
[1] Experiment 1 1. Preparation of rubber composition [Rubber used as base rubber]
= CA 02892484 2015-05-21 NR: RSS#3 (masticated) BR: Nipol BR1220 (manufactured by Zeon Corporation: high-cis BR) CR: Showa Denko Chloroprene WRT (manufactured by Showa Denko K.K.)
[1] Experiment 1 1. Preparation of rubber composition [Rubber used as base rubber]
= CA 02892484 2015-05-21 NR: RSS#3 (masticated) BR: Nipol BR1220 (manufactured by Zeon Corporation: high-cis BR) CR: Showa Denko Chloroprene WRT (manufactured by Showa Denko K.K.)
[0041]
Appropriate amounts of various additives (carbon, sulfur, a vulcanization accelerator, a vulcanization accelerator aid, an antioxidant, a plasticizer, and the like) were added to each of the base rubbers in which the rubbers described above were compounded at the ratios (parts by mass) shown in Tables I to III, followed by mixing.
Thus, rubber compositions A to N shown in Tables Ito III were prepared (composition ratios of the additives were appropriately changed in accordance with the type and ratio of the base rubbers).
Appropriate amounts of various additives (carbon, sulfur, a vulcanization accelerator, a vulcanization accelerator aid, an antioxidant, a plasticizer, and the like) were added to each of the base rubbers in which the rubbers described above were compounded at the ratios (parts by mass) shown in Tables I to III, followed by mixing.
Thus, rubber compositions A to N shown in Tables Ito III were prepared (composition ratios of the additives were appropriately changed in accordance with the type and ratio of the base rubbers).
[0042]
2. Quality evaluation of rubber Regarding each of the prepared rubber compositions, tackiness in the unvulcanized state, and cold resistance, ozone resistance (dynamic ozone resistance), and rubber-rubber adhesiveness after vulcanization (of the products) were measured and evaluated by the methods, under the conditions, and on the basis of criteria described below under the head of [Evaluation methods and criteria]. The evaluation results are shown in Tables Ito III.
2. Quality evaluation of rubber Regarding each of the prepared rubber compositions, tackiness in the unvulcanized state, and cold resistance, ozone resistance (dynamic ozone resistance), and rubber-rubber adhesiveness after vulcanization (of the products) were measured and evaluated by the methods, under the conditions, and on the basis of criteria described below under the head of [Evaluation methods and criteria]. The evaluation results are shown in Tables Ito III.
[0043]
[Evaluation methods and criteria]
-Cold resistance: The brittle temperature was measured on the basis of JIS
K6261.
When the measured value was equal to or lower than -55 C, it was evaluated as passed.
When the measured value was equal to or lower than -60 C (brittle temperature at a level usable even in very cold climates), it was evaluated as more preferable.
-Ozone resistance (dynamic ozone resistance): A test was performed on the basis of the JIS standard: JIS K6259, and presence or absence of cracks was observed.
As the specimen, a JIS No. 3 dumbbell specimen was used.
= Tackiness: After unvulcanized rubber sheets were bonded together, peel strength was measured by a 180 peeling test (peeling speed: 50 mm/min). When the measured value was equal to or more than 0.20 kgf/25 mm, it was evaluated as passed.
When the measured value was equal to or more than 0.40 kgf/25 mm, it was evaluated as more preferable.
-Adhesiveness: After unvulcanized rubber sheets were bonded together and vulcanizing pressed, rubber-rubber adhesion was measured by a 180 peeling test (peeling speed: 50 mm/min). When the measured value was equal to or more than 10 kgf/25 mm, it was evaluated as passed. When the measured value was equal to or more than kgf/25 mm, it was evaluated as more preferable.
[Evaluation methods and criteria]
-Cold resistance: The brittle temperature was measured on the basis of JIS
K6261.
When the measured value was equal to or lower than -55 C, it was evaluated as passed.
When the measured value was equal to or lower than -60 C (brittle temperature at a level usable even in very cold climates), it was evaluated as more preferable.
-Ozone resistance (dynamic ozone resistance): A test was performed on the basis of the JIS standard: JIS K6259, and presence or absence of cracks was observed.
As the specimen, a JIS No. 3 dumbbell specimen was used.
= Tackiness: After unvulcanized rubber sheets were bonded together, peel strength was measured by a 180 peeling test (peeling speed: 50 mm/min). When the measured value was equal to or more than 0.20 kgf/25 mm, it was evaluated as passed.
When the measured value was equal to or more than 0.40 kgf/25 mm, it was evaluated as more preferable.
-Adhesiveness: After unvulcanized rubber sheets were bonded together and vulcanizing pressed, rubber-rubber adhesion was measured by a 180 peeling test (peeling speed: 50 mm/min). When the measured value was equal to or more than 10 kgf/25 mm, it was evaluated as passed. When the measured value was equal to or more than kgf/25 mm, it was evaluated as more preferable.
[0044]
[Table I]
A
Base rubber NR 20 40 50 60 BR
Cold resistance (brittle temperature C) Ozone resistance Absent Absent Absent Absent Present (presence or absence of cracks) Tackiness (kgf/25mm) 0.80 1.32 1.10 1.20 1.70 Adhesiveness (kgf/25mm) 31.2 7.0 5.6 5.0 8.0
[Table I]
A
Base rubber NR 20 40 50 60 BR
Cold resistance (brittle temperature C) Ozone resistance Absent Absent Absent Absent Present (presence or absence of cracks) Tackiness (kgf/25mm) 0.80 1.32 1.10 1.20 1.70 Adhesiveness (kgf/25mm) 31.2 7.0 5.6 5.0 8.0
[0045]
[Table II]
Base rubber NR 10 20 25 30 Cold resistance -53 <-70 <-70 <-70 (brittle temperature C) Ozone resistance Absent Absent Absent Present (presence or absence of cracks) Tackiness (kgf/25mm) 0.80 0.90 0.95 1.00 Adhesiveness (kgf/25mm) 12.0 14.4 17.0 20.5
[Table II]
Base rubber NR 10 20 25 30 Cold resistance -53 <-70 <-70 <-70 (brittle temperature C) Ozone resistance Absent Absent Absent Present (presence or absence of cracks) Tackiness (kgf/25mm) 0.80 0.90 0.95 1.00 Adhesiveness (kgf/25mm) 12.0 14.4 17.0 20.5
[0046]
[Table III]
Base rubber NR 30 25 15 10 Cold resistance -58 -65 <-70 <-70 <-70 (brittle temperature C) Ozone resistance Absent Absent Absent Absent Absent (presence or absence of cracks) Tackiness (kgf/25mm) 1.60 1.00 0.55 0.22 0.13 Adhesiveness (kgf/25rnm) 13.0 13.9 14.9 15.9 23.7
[Table III]
Base rubber NR 30 25 15 10 Cold resistance -58 -65 <-70 <-70 <-70 (brittle temperature C) Ozone resistance Absent Absent Absent Absent Absent (presence or absence of cracks) Tackiness (kgf/25mm) 1.60 1.00 0.55 0.22 0.13 Adhesiveness (kgf/25rnm) 13.0 13.9 14.9 15.9 23.7
[0047]
[Consideration based on Tables Ito III]
In E and I in which the composition ratio of CR (on the basis of the total of CR, BR, and NR) is 40% by mass, the ozone resistance (dynamic ozone resistance) is low and cracks occur. This result suggests that in order to maintain the ozone resistance (dynamic ozone resistance), the composition ratio of CR should be 50% by mass or more.
On the other hand, in A in which the composition ratio of CR is 100% by mass and in B
and F in which the composition ratio of CR is 80% by mass, cold resistance is lacking (the brittle temperature is higher than -55 C). In F in which 10% by mass of BR is compounded, although the cold resistance is improved, the brittle temperature is not equal to or lower than -55 C, that is, does not meet the acceptance criterion. This result suggests that in order to pass the evaluation of the cold resistance, the composition ratio of CR should be 75% by mass or less.
[Consideration based on Tables Ito III]
In E and I in which the composition ratio of CR (on the basis of the total of CR, BR, and NR) is 40% by mass, the ozone resistance (dynamic ozone resistance) is low and cracks occur. This result suggests that in order to maintain the ozone resistance (dynamic ozone resistance), the composition ratio of CR should be 50% by mass or more.
On the other hand, in A in which the composition ratio of CR is 100% by mass and in B
and F in which the composition ratio of CR is 80% by mass, cold resistance is lacking (the brittle temperature is higher than -55 C). In F in which 10% by mass of BR is compounded, although the cold resistance is improved, the brittle temperature is not equal to or lower than -55 C, that is, does not meet the acceptance criterion. This result suggests that in order to pass the evaluation of the cold resistance, the composition ratio of CR should be 75% by mass or less.
[0048]
In B, C, D, and E in which although NR is compounded into CR, BR is not compounded, the rubber-rubber adhesion is low and the adhesiveness that meets the acceptance criterion is not obtained. Furthermore, in the case of C in which BR is not compounded (that is, the composition ratio of NR is large and exceeds 35% by mass), although the composition ratio of CR is in the range of 50% to 75% by mass, the brittle temperature is not equal to or lower than -55 C, and satisfactory cold resistance is not obtained.
In B, C, D, and E in which although NR is compounded into CR, BR is not compounded, the rubber-rubber adhesion is low and the adhesiveness that meets the acceptance criterion is not obtained. Furthermore, in the case of C in which BR is not compounded (that is, the composition ratio of NR is large and exceeds 35% by mass), although the composition ratio of CR is in the range of 50% to 75% by mass, the brittle temperature is not equal to or lower than -55 C, and satisfactory cold resistance is not obtained.
[0049]
On the other hand, as the results of J, K, L, M, and N show, by compounding 10%
by mass or more of BR, it is possible to obtain adhesiveness and cold resistance that meet the acceptance criteria. Furthermore, as the composition ratio of BR increases (i.e., the composition ratio of NR decreases), cold resistance improves (the brittle temperature decreases), but tackiness decreases. In N in which the composition ratio of BR
is 40% by mass and NR is not compounded, tackiness that meets the acceptance criterion is not obtained. These results suggest that in order to obtain cold resistance, ozone resistance, tackiness, and adhesiveness that meet the acceptance criteria, (in addition to setting the composition ratio of CR to 50% to 75% by mass), the composition ratio of BR
should be set in the range of 10% to 35% by mass, and the composition ratio of NR should be set in the range of 10% to 35% by mass. Note that, in J in which the composition ratio of BR is 10% by mass, the brittle temperature equal to or lower than -60 C, which is the preferable cold resistance, is not obtained. Furthermore, in M in which the composition ratio of NR
is 10% by mass, the measured value equal to or more than 0.40 kgf/25 mm, which is the preferable tackiness, is not obtained. This result suggests that the composition ratio of BR is preferably 15% to 30% by mass, the composition ratio of NR is preferably 15% to 30% by mass, and therefore, the composition ratio of CR is preferably 50% to 70% by mass.
On the other hand, as the results of J, K, L, M, and N show, by compounding 10%
by mass or more of BR, it is possible to obtain adhesiveness and cold resistance that meet the acceptance criteria. Furthermore, as the composition ratio of BR increases (i.e., the composition ratio of NR decreases), cold resistance improves (the brittle temperature decreases), but tackiness decreases. In N in which the composition ratio of BR
is 40% by mass and NR is not compounded, tackiness that meets the acceptance criterion is not obtained. These results suggest that in order to obtain cold resistance, ozone resistance, tackiness, and adhesiveness that meet the acceptance criteria, (in addition to setting the composition ratio of CR to 50% to 75% by mass), the composition ratio of BR
should be set in the range of 10% to 35% by mass, and the composition ratio of NR should be set in the range of 10% to 35% by mass. Note that, in J in which the composition ratio of BR is 10% by mass, the brittle temperature equal to or lower than -60 C, which is the preferable cold resistance, is not obtained. Furthermore, in M in which the composition ratio of NR
is 10% by mass, the measured value equal to or more than 0.40 kgf/25 mm, which is the preferable tackiness, is not obtained. This result suggests that the composition ratio of BR is preferably 15% to 30% by mass, the composition ratio of NR is preferably 15% to 30% by mass, and therefore, the composition ratio of CR is preferably 50% to 70% by mass.
[0050]
[2] Experiment 2 1. Preparation of rubber composition [Rubber used as base rubber]
NR: RSS#3 (masticated) E-SBR: Nipol 1502 (manufactured by Zeon Corporation) NBR: Nipol DN401LL (manufactured by Zeon Corporation) BR: Nipol BR1220 (manufactured by Zeon Corporation: high-cis BR) CR: Showa Denko Chloroprene WRT (manufactured by Showa Denko K.K.)
[2] Experiment 2 1. Preparation of rubber composition [Rubber used as base rubber]
NR: RSS#3 (masticated) E-SBR: Nipol 1502 (manufactured by Zeon Corporation) NBR: Nipol DN401LL (manufactured by Zeon Corporation) BR: Nipol BR1220 (manufactured by Zeon Corporation: high-cis BR) CR: Showa Denko Chloroprene WRT (manufactured by Showa Denko K.K.)
[0051]
Appropriate amounts of various additives (carbon, sulfur, a vulcanization accelerator, a vulcanization accelerator aid, an antioxidant, and a plasticizer) were added to each of the base rubbers in which the rubbers described above were compounded at the ratios (parts by mass) shown in Tables IV and V, followed by mixing. Thus, rubber compositions shown in Tables IV and V were prepared (composition ratios of the additives were appropriately changed in accordance with the type and ratio of the base rubbers).
Appropriate amounts of various additives (carbon, sulfur, a vulcanization accelerator, a vulcanization accelerator aid, an antioxidant, and a plasticizer) were added to each of the base rubbers in which the rubbers described above were compounded at the ratios (parts by mass) shown in Tables IV and V, followed by mixing. Thus, rubber compositions shown in Tables IV and V were prepared (composition ratios of the additives were appropriately changed in accordance with the type and ratio of the base rubbers).
[0052]
2. Quality evaluation of rubber Regarding each of the prepared rubber compositions, tackiness in the unvulcanized state, and cold resistance, ozone resistance (dynamic ozone resistance), and adhesiveness after vulcanization (of the products) were measured and evaluated by the methods, under the conditions, and on the basis of criteria described under the head of [Evaluation methods and criteria] of Experiment 1. The evaluation results are shown in Tables IV
and V.
Note that Tables IV and V also show the evaluation results of G in Experiment 1 for comparison.
2. Quality evaluation of rubber Regarding each of the prepared rubber compositions, tackiness in the unvulcanized state, and cold resistance, ozone resistance (dynamic ozone resistance), and adhesiveness after vulcanization (of the products) were measured and evaluated by the methods, under the conditions, and on the basis of criteria described under the head of [Evaluation methods and criteria] of Experiment 1. The evaluation results are shown in Tables IV
and V.
Note that Tables IV and V also show the evaluation results of G in Experiment 1 for comparison.
[0053]
[Table IV]
Basel 0 Base rubber BR 20 20 20 20 20 NBR
Cold resistance <-70 -44.5 <-70 <-70 <-70 <-70 (brittle temperature C) Ozone resistance (presence or absence of Absent Absent Absent Absent Absent Absent cracks) Tackiness (kgf/25mm) 0.90 0.22 0.82 0.60 0.37 0.19 Adhesiveness (kgf/25mm) 14.4 33.1 20.1 25.2 27.6 28.3
[Table IV]
Basel 0 Base rubber BR 20 20 20 20 20 NBR
Cold resistance <-70 -44.5 <-70 <-70 <-70 <-70 (brittle temperature C) Ozone resistance (presence or absence of Absent Absent Absent Absent Absent Absent cracks) Tackiness (kgf/25mm) 0.90 0.22 0.82 0.60 0.37 0.19 Adhesiveness (kgf/25mm) 14.4 33.1 20.1 25.2 27.6 28.3
[0054]
[Table V]
Base 2 S T U V
Base rubber BR 20 20 20 20 20 SBR
Cold resistance <-70 -37.5 <-70 <-70 -67.5 -66.5 (brittle temperature C) Ozone resistance (presence or absence of Absent Absent Absent Absent Absent Absent cracks) Tackiness (kgf/25mm) 0.90 1.36 0.75 0.49 0.31 0.21 Adhesiveness (kgf/25mm) 14.4 39.1 18.2 19.9 18.5 19.6
[Table V]
Base 2 S T U V
Base rubber BR 20 20 20 20 20 SBR
Cold resistance <-70 -37.5 <-70 <-70 -67.5 -66.5 (brittle temperature C) Ozone resistance (presence or absence of Absent Absent Absent Absent Absent Absent cracks) Tackiness (kgf/25mm) 0.90 1.36 0.75 0.49 0.31 0.21 Adhesiveness (kgf/25mm) 14.4 39.1 18.2 19.9 18.5 19.6
[0055]
[Consideration based on Tables IV and V]
In 0, P, Q, and R described in Table IV, the composition ratios of CR and BR
are the same as those of G which is a specific example of the first embodiment, but part (25%, 50%, or 75%) or all of NR in G is replaced with SBR. In S, T, U, and V
described in Table V, the composition ratios of CR and BR are the same as those of G which is a specific example of the first embodiment, but part (25%, 50%, or 75%) or all of NR in G is replaced with NBR.
[Consideration based on Tables IV and V]
In 0, P, Q, and R described in Table IV, the composition ratios of CR and BR
are the same as those of G which is a specific example of the first embodiment, but part (25%, 50%, or 75%) or all of NR in G is replaced with SBR. In S, T, U, and V
described in Table V, the composition ratios of CR and BR are the same as those of G which is a specific example of the first embodiment, but part (25%, 50%, or 75%) or all of NR in G is replaced with NBR.
[0056]
As is clear from Tables IV and V, in 0, P, Q, and R and in S, T, U, and V, excellent cold resistance and ozone resistance equivalent to those in the case of G are obtained.
Furthermore, the adhesiveness is improved compared with G, and the rubber-rubber adhesion suitable for diaphragm use (15 kgf/25 mm or more) is obtained (in G, only an adhesiveness of less than 15 kgf/25 mm is obtained). The results on the adhesiveness shown in Tables IV and V suggest that in order to improve adhesiveness, in the rubber composition according to the first embodiment, it is preferable to replace part, specifically 10% by mass or more, of NR is replaced with SBR or NBR.
As is clear from Tables IV and V, in 0, P, Q, and R and in S, T, U, and V, excellent cold resistance and ozone resistance equivalent to those in the case of G are obtained.
Furthermore, the adhesiveness is improved compared with G, and the rubber-rubber adhesion suitable for diaphragm use (15 kgf/25 mm or more) is obtained (in G, only an adhesiveness of less than 15 kgf/25 mm is obtained). The results on the adhesiveness shown in Tables IV and V suggest that in order to improve adhesiveness, in the rubber composition according to the first embodiment, it is preferable to replace part, specifically 10% by mass or more, of NR is replaced with SBR or NBR.
[0057]
On the other hand, as shown in the column of tackiness in Tables IV and V, in Q in which 75% of NR of G is replaced with SBR and R in which all is replaced with SBR and in U in which 75% of NR of G is replaced with NBR and V in which all is replaced with NBR, tackiness decreases, and suitable tackiness (0.4 kgf/25 mm or more) is not obtained.
Therefore, it is suggested that, in order to obtain suitable tackiness, the percentage of NR to be replaced with SBR or NBR is preferably 60% by mass or less of NR.
On the other hand, as shown in the column of tackiness in Tables IV and V, in Q in which 75% of NR of G is replaced with SBR and R in which all is replaced with SBR and in U in which 75% of NR of G is replaced with NBR and V in which all is replaced with NBR, tackiness decreases, and suitable tackiness (0.4 kgf/25 mm or more) is not obtained.
Therefore, it is suggested that, in order to obtain suitable tackiness, the percentage of NR to be replaced with SBR or NBR is preferably 60% by mass or less of NR.
[0058]
Moreover, in the rubber composition of Base 1 in which NR and BR are not compounded and SBR only, in an amount of 20% by mass, is compounded into CR, and in the rubber composition of Base 2 in which NBR only, in an amount of 20% by mass, is compounded, the cold resistance is low and the brittle temperature is higher than -50 C.
Furthermore, in U in which 75% of NR is replaced with NBR and in V in which all is replaced with NBR, the cold resistance tends to decrease (although the standard is met).
Industrial Applicability
Moreover, in the rubber composition of Base 1 in which NR and BR are not compounded and SBR only, in an amount of 20% by mass, is compounded into CR, and in the rubber composition of Base 2 in which NBR only, in an amount of 20% by mass, is compounded, the cold resistance is low and the brittle temperature is higher than -50 C.
Furthermore, in U in which 75% of NR is replaced with NBR and in V in which all is replaced with NBR, the cold resistance tends to decrease (although the standard is met).
Industrial Applicability
[0059]
The first and second embodiments of the invention can be suitably used in air springs for vehicle use and the like, in particular, in air springs for railway vehicle use used in cold climates.
The first and second embodiments of the invention can be suitably used in air springs for vehicle use and the like, in particular, in air springs for railway vehicle use used in cold climates.
Claims (4)
- [Claim 1]
A cold-resistant rubber composition comprising butadiene rubber, chloroprene rubber, and natural rubber, wherein the content of the butadiene rubber is 10 to 35 parts by mass, the content of the chloroprene rubber is 50 to 75 parts by mass, and the content of the natural rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the butadiene rubber, the chloroprene rubber, and the natural rubber. - [Claim 2]
The cold-resistant rubber composition according to Claim 1, wherein part of the natural rubber is replaced with at least one specific rubber selected from the group consisting of styrene-butadiene rubber and nitrile rubber. - [Claim 3]
The cold-resistant rubber composition according to Claim 2, wherein the content of the butadiene rubber is 10 to 35 parts by mass, the content of the chloroprene rubber is 50 to 75 parts by mass, and the total content of the natural rubber and the specific rubber is 10 to 35 parts by mass, relative to 100 parts by mass of the total of the butadiene rubber, the chloroprene rubber, the natural rubber, and the specific rubber, and the content of the specific rubber is 10% to 60% by mass relative to the total content of the natural rubber and the specific rubber. - [Claim 4]
An air spring for railway vehicle use formed by using the cold-resistant rubber composition according to Claim 1, Claim 2, or Claim 3.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013271623A JP5885131B2 (en) | 2013-12-27 | 2013-12-27 | Cold resistant rubber composition |
| JP2013-271623 | 2013-12-27 | ||
| PCT/JP2014/083552 WO2015060466A1 (en) | 2013-12-27 | 2014-12-18 | Cold-resistant rubber composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2892484A1 true CA2892484A1 (en) | 2015-04-30 |
| CA2892484C CA2892484C (en) | 2016-08-23 |
Family
ID=52993044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2892484A Active CA2892484C (en) | 2013-12-27 | 2014-12-18 | Cold-resistant rubber composition |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP5885131B2 (en) |
| CN (1) | CN104837912A (en) |
| CA (1) | CA2892484C (en) |
| RU (1) | RU2577363C1 (en) |
| WO (1) | WO2015060466A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106084786A (en) * | 2016-07-13 | 2016-11-09 | 安徽奥丰汽车配件有限公司 | A kind of high temperature resistant vehicle rubber tyre material |
| JP6312183B1 (en) * | 2017-03-31 | 2018-04-18 | 福岡県 | Rubber composition for use in high pressure gas seal member and high pressure gas seal member |
| CN107163330A (en) * | 2017-06-08 | 2017-09-15 | 合肥帧讯低温科技有限公司 | Low-temperature-resistant heat-insulating material and preparation method thereof |
| CN107141529A (en) * | 2017-06-14 | 2017-09-08 | 陈丽 | A kind of high intensity engineering tire glue |
| CN107118402A (en) * | 2017-06-14 | 2017-09-01 | 陈丽 | A kind of all-year tire tire glue |
| JP7132783B2 (en) | 2018-07-25 | 2022-09-07 | デンカ株式会社 | Rubber composition, vulcanized rubber and molded products thereof |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| RU2326902C1 (en) * | 2006-08-16 | 2008-06-20 | Открытое акционерное общество "Ярославский шиноремонтный завод" (ОАО "ЯШРЗ") | Rubber mix for production of rail and sleeper pads for damping rail braces |
| CN101353453B (en) * | 2007-07-27 | 2012-10-10 | 中国铁道科学研究院金属及化学研究所 | Chloroprene rubber composition having improved cold tolerance |
| JP2010013504A (en) * | 2008-07-01 | 2010-01-21 | Toyo Tire & Rubber Co Ltd | Rubber composition for air spring, and air spring |
| RU2400497C2 (en) * | 2008-12-26 | 2010-09-27 | Открытое акционерное общество "Российские железные дороги" (ОАО "РЖД") | Rubber mix for making rail and sleeper pads for damping rail braces |
| CN101602866B (en) * | 2009-07-09 | 2011-09-14 | 四机赛瓦石油钻采设备有限公司 | Cold-resistant rubber material suitable for preparing air sac and preparation method thereof |
| JP5690120B2 (en) * | 2010-11-26 | 2015-03-25 | 電気化学工業株式会社 | Chloroprene rubber composition, vulcanized product thereof and molded article |
| AU2012341843B2 (en) * | 2011-11-22 | 2015-02-26 | Bridgestone Corporation | Rubber composition, and hose |
| JP5813480B2 (en) * | 2011-11-22 | 2015-11-17 | 株式会社ブリヂストン | Rubber composition for hose and hose |
| JP5998490B2 (en) * | 2012-01-27 | 2016-09-28 | 株式会社ブリヂストン | Rubber composition for air spring |
| JP5991855B2 (en) * | 2012-06-01 | 2016-09-14 | 東洋ゴム工業株式会社 | Rubber composition |
| CN103113641B (en) * | 2013-02-04 | 2014-12-31 | 无锡宝通带业股份有限公司 | Low-hardness high-fatigue-drawing-resistance flame-retardant steel wire rope core conveyer belt core rubber and preparation method thereof |
| CN103304863A (en) * | 2013-06-28 | 2013-09-18 | 青岛福凯橡塑新材料有限公司 | Rubber core adhesive and use thereof |
-
2013
- 2013-12-27 JP JP2013271623A patent/JP5885131B2/en active Active
-
2014
- 2014-12-18 CA CA2892484A patent/CA2892484C/en active Active
- 2014-12-18 WO PCT/JP2014/083552 patent/WO2015060466A1/en active Application Filing
- 2014-12-18 CN CN201480003199.1A patent/CN104837912A/en active Pending
- 2014-12-18 RU RU2015119965/05A patent/RU2577363C1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| RU2577363C1 (en) | 2016-03-20 |
| CA2892484C (en) | 2016-08-23 |
| JP5885131B2 (en) | 2016-03-15 |
| JP2015124354A (en) | 2015-07-06 |
| CN104837912A (en) | 2015-08-12 |
| WO2015060466A1 (en) | 2015-04-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2892484C (en) | Cold-resistant rubber composition | |
| JP5735106B2 (en) | Rubber mixture | |
| IN2012DN06310A (en) | ||
| JP5687338B2 (en) | Rubber mixture | |
| US10011428B2 (en) | Coating rubber composition for conveyer belts | |
| CN105237835A (en) | Rubber material for wear-proof sealing part | |
| JP2010174232A (en) | Rubber composition for tire | |
| JP2010174231A (en) | Rubber composition for tire | |
| CN106317526A (en) | Fatigue-resistant deflection-resistant rubber material | |
| JP6473302B2 (en) | tire | |
| WO2016084892A1 (en) | Rubber composition for tire bead insulation, and pneumatic tire using same | |
| WO2018179629A1 (en) | Rubber coating composition for use in conveyor belt, laminate, and conveyor belt | |
| JP2005075888A (en) | Rubber composition for steel coating | |
| JP6642067B2 (en) | Rubber composition for tire and tire | |
| CN107746479B (en) | High-viscosity rubber for engine suspension and preparation method thereof | |
| JP5949820B2 (en) | Rubber composition and pneumatic tire using the same | |
| WO2014203695A1 (en) | Rubber composition for vibration-proof rubber | |
| JPH10219033A (en) | Rubber composition for high-attenuation support | |
| JP2012116909A (en) | Rubber composition for tire sidewall and pneumatic tire using the same | |
| JP2020147727A (en) | Rubber composition for steel cord adhesion and conveyor belt | |
| KR20190091159A (en) | Rubber composition for ultra low permeability fuel hose useful automobile and hose used fuel hose | |
| CN113939558B (en) | Rubber composition and tire | |
| JPH11123907A (en) | Pneumatic tire | |
| JP2001342295A (en) | Rubber composition for laminate improved in fracture characteristic | |
| JP7293720B2 (en) | Steel cord adhesive rubber composition and conveyor belt |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |
Effective date: 20150521 |