Rubber, seal component, and hose

Abstract

A rubber includes 5 parts by mass to 45 parts by mass of an uncross-linked EPM relative to 100 parts by mass of a cross-linked rubber polymer (other than EPM), and an oil in an amount equal to or more than the amount of the EPM. The rubber is foamed and has a specific gravity of more than 0.3 and 0.8 or less. A weather strip 1 and a hose 2 are formed of the rubber.

Claims

1. A foamed rubber consisting essentially of: a rubber polymer in an amount of 105 parts by mass to 145 parts by mass, the rubber polymer consisting of a cross-linked EPDM rubber in an amount of 100 parts by mass and an uncross-linked EPM rubber that is a solid in an amount 5 parts by mass to 45 parts by mass, and a hydrocarbon-based oil having a weight average molecular weight of 1,500 or less in an amount equal to or more than the amount of the EPM, and wherein the foamed rubber was obtained by vulcanizing a mixture of the rubber polymer and the hydrocarbon-based oil using a vulcanizing agent that vulcanized the EPDM rubber and did not cross-link the uncross-linked EPM rubber, and the foamed rubber material has a specific gravity of more than 0.3 and 0.8 or less.

2. The foamed rubber according to claim 1, wherein a mass ratio of the hydrocarbon-based oil to the EPM is 1 to 10.

3. The foamed rubber according to claim 1, wherein the mixture of the rubber polymer and the hydrocarbon-based oil further consists essentially of oil stearic acid in an amount of 0.5 parts by mass to 8 parts by mass per the 100 parts by mass of the EPDM.

4. The foamed rubber according to claim 1, wherein the mixture of the rubber polymer and the hydrocarbon-based oil further consists essentially of stearic acid in an amount of 2 parts by mass to 5 parts by mass per the 100 parts by mass of the EPDM.

5. The foamed rubber according to claim 1, wherein the mixture of the rubber polymer and the hydrocarbon-based oil further consists essentially of stearic acid in an amount of 0.5 parts by mass to 5 parts by mass per the 100 parts by mass of the EPDM, and a fatty acid ester-based processing aid in an amount of 0.5 parts by mass to 20 parts by mass per the 100 parts by mass of the EPDM.

6. A seal component formed of the foamed rubber according to claim 1.

7. A hose formed of the foamed rubber according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1A is a cross-sectional view of a weather strip for automobiles, and FIG. 1B is a cross-sectional view of a hose for automobiles, where the weather strip and the hose are both molded products formed of a rubber of Example.

MODES FOR CARRYING OUT THE INVENTION

(2) 1. Cross-Linked Rubber Polymer

(3) Examples of the cross-linked rubber polymer (other than EPM) include, but not particularly limited to, an ethylene-propylene-non-conjugated diene rubber (EPDM), an isobutylene-isoprene rubber (IIR), an isoprene rubber (IR), a natural rubber (NR), a butadiene rubber (BR), and a styrene-butadiene rubber (SBR).

(4) In the case of EPDM, the ethylene content is not particularly limited, and is preferably 60% by mass or less. When the ethylene content is high, the low-temperature characteristics of vulcanized rubber may be deteriorated.

(5) Examples of non-conjugated diene in EPDM include, but not particularly limited to, 5-ethylidene-2-norbornene (ENB), dicyclopentadiene (DCPD), and 1,4-hexadiene (1,4-HD).

(6) As EPDM, a non-oil-extended EPDM or an oil-extended EPDM can be used. An oil component contained in the oil-extended EPDM is included in oil in the present invention.

(7) 2. Uncross-Linked EPM

(8) The amount of uncross-linked EPM is not particularly limited, and is preferably 5 parts by mass to 45 parts by mass, and more preferably 10 parts by mass to 30 parts by mass, relative to 100 parts by mass of the rubber polymer. When the amount of uncross-linked EPM is less than 5 parts by mass, the effect of enhancing the sound insulation is decreased. When it is more than 45 parts by mass, the viscosity of the material is increased.

(9) The ethylene content of EPM is not particularly limited, and is preferably 60% by mass or less. When the ethylene content is high, the low-temperature characteristics are deteriorated.

(10) As EPM, a non-oil-extended EPM or an oil-extended EPM can be used. An oil component contained in the oil-extended EPM is included in oil in the present invention.

(11) In the case where the rubber of the present invention contains the cross-linked rubber polymer and the uncross-linked EPM, a vulcanizing agent that vulcanizes the rubber polymer and does not cross-link EPM (e.g., sulfur) is used, and a vulcanizing agent that cross-links EPM (e.g., organic peroxide) is not be used.

(12) 3. Oil

(13) The amount of oil is not particularly limited, and is preferably an amount equal to or more than the amount in parts by mass of EPM. This is because the rubber is wound around a roll during rolling and kneading and the processability is favorable.

(14) The mass ratio of oil to EPM is not particularly limited, and is preferably 1 to 10, and more preferably 2 to 8. When the mass ratio is less than 1, the processability is deteriorated.

(15) When the mass ratio is more than 10, plasticization is excessively promoted, and the processability is deteriorated.

(16) Examples of the oil include, but not particularly limited to, a paraffinic oil, a naphthene-based oil, an aromatic oil, and a hydrocarbon-based oil obtained by blending them. The weight average molecular weight of the hydrocarbon-based oil is preferably 1,500 or less in terms of low viscosity and favorable processability. The lower limit of the weight average molecular weight is not particularly limited, and is preferably 100 in terms of availability. Most of oil that is conventionally added to a rubber, such as an extender oil and a process oil, can be used as a preferable hydrocarbon-based oil having the weight average molecular weight of 100 to 1,500.

(17) 4. Stearic Acid

(18) In an aspect of (a), the stearic acid is contained in an amount of 0.5 parts by mass to 5 parts by mass, and preferably 1 to 5 parts by mass, relative to 100 parts by mass of the rubber polymer. When the amount of the stearic acid is 1 part by mass or more, the sound insulation is further enhanced and the viscosity in the state of a material is further decreased.

(19) 5. Fatty Acid Ester-Based Processing Aid

(20) In the aspect of (a), the fatty acid ester-based processing aid may or may not be contained.

(21) In an aspect of (b), the fatty acid ester-based processing aid is contained in an amount of 0.5 parts by mass to 20 parts by mass, and preferably 1 part by mass to 10 parts by mass, relative to 100 parts by mass of the rubber polymer. When the amount of the fatty acid ester-based processing aid is 1 part by mass or more, the viscosity in the state of a material is further decreased. The upper limit of the fatty acid ester-based processing aid is not particularly limited. When the upper limit thereof is more than 20 parts by mass, the proportions of other components are relatively decreased, and the physical properties may be affected. Therefore, an upper limit of about 10 parts by mass is appropriate.

(22) 6. Other Compounding Materials

(23) In the rubber, other compounding materials may be mixed. Examples of the other compounding materials include, but not particularly limited to, carbon black, calcium carbonate, zinc oxide, an age resistor, a colorant, a foaming agent, and a vulcanization accelerator.

(24) 7. Molded Product Formed of Rubber

(25) The molded product formed of the rubber of the present invention is not particularly limited. In terms of utilizing its high sound insulation, the molded product is a seal component. Examples of the seal component include sealing materials of weather strips, door glass runs, window frames, and gaskets of engines for vehicles such as an automobile, a railway vehicle, a ship, and an air craft, sealing materials for foods, sealing materials for interior and exterior components, and sealing materials for electrical components. Further, examples thereof include seal components of window frames of buildings. In addition to the seal component, examples of the molded product include hoses including a hose for automobiles. Leakage of flow sound of a flow substance in the hose to the exterior can be suppressed.

EXAMPLES

(26) Rubber materials for each rubber in Examples 1 to 44 and Comparative Examples 1 to 5 at a combination (the value is in parts by mass) shown in Tables 1 to 4 described below were prepared. A foamed rubber sheet was molded from each of the rubbers.

(27) TABLE-US-00001 TABLE 1 Sample name Example 1 Example 2 Example 3 Example 4 Example 5 EPDM Oil-extended EPDM 120 120 120 120 120 (oil-extended amount of (Polymer 100) (Polymer 100) (Polymer 100) (Polymer 100) (Polymer 100) extender oil: 20 phr) (Oil 20) (Oil 20) (Oil 20) (Oil 20) (Oil 20) Oil Process oil 60 55 50 40 30 EPM EPM (1) 10 15 20 30 40 EPM (2) Compounding Carbon black 120 120 120 120 120 material Calcium carbonate 50 50 50 50 50 Zinc oxide 7 7 7 7 7 Stearic acid 1 1 1 1 1 Other 5 5 5 5 5 Vulcanizing Sulfur powder 1.2 1.2 1.2 1.2 1.2 agent Sulfur Organic vulcanizing agent 0.6 0.6 0.6 0.6 0.6 compound (morpholine-based) Thiazole-based 2 2 2 2 2 Dithiocarbamate-based 1.4 1.4 1.4 1.4 1.4 Sulfenamide-based 0.3 0.3 0.3 0.3 0.3 Foaming agent OBSH foaming agent 3.04 3.04 3.04 3.04 3.04 Mass ratio Oil/EPM 8.0 5.0 3.5 2.0 1.3 Roll processability Physical Sound insulation degree 42.9 43.2 43.3 43.2 42.6 property (dBA) of 0.4 to 10 kHz Specific gravity about 0.7 about 0.7 about 0.7 about 0.7 about 0.7 Sample name Example 6 Example 7 Example 8 Example 9 Example 10 EPDM Oil-extended EPDM 120 120 120 120 120 (oil-extended amount of (Polymer 100) (Polymer 100) (Polymer 100) (Polymer 100) (Polymer 100) extender oil: 20 phr) (Oil 20) (Oil 20) (Oil 20) (Oil 20) (Oil 20) Oil Process oil 50 50 50 50 50 EPM EPM (1) 15 15 15 15 EPM (2) 20 Compounding Carbon black 120 120 120 120 120 material Calcium carbonate 50 50 50 50 50 Zinc oxide 7 7 7 7 7 Stearic acid 1 0.5 2 3 5 Other 5 5 5 5 5 Vulcanizing Sulfur powder 1.2 1.2 1.2 1.2 1.2 agent Sulfur Organic vulcanizing agent 0.6 0.6 0.6 0.6 0.6 compound (morpholine-based) Thiazole-based 2 2 2 2 2 Dithiocarbamate-based 1.4 1.4 1.4 1.4 1.4 Sulfenamide-based 0.3 0.3 0.3 0.3 0.3 Foaming agent OBSH foaming agent 3.04 3.04 3.04 3.04 3.04 Mass ratio Oil/EPM 3.5 4.7 4.7 4.7 4.7 Roll processability Physical Sound insulation degree 43.8 43.4 44.1 43.5 44.0 property (dBA) of 0.4 to 10 kHz Specific gravity about 0.7 about 0.7 about 0.7 about 0.7 about 0.7 Comparative Comparative Comparative Sample name Example 11 Example 1 Example 2 Example 3 EPDM Oil-extended EPDM 120 120 120 120 (oil-extended amount of (Polymer 100) (Polymer 100) (Polymer 100) (Polymer 100) extender oil: 20 phr) (Oil 20) (Oil 20) (Oil 20) (Oil 20) Oil Process oil 50 70 0 20 EPM EPM (1) 15 70 50 EPM (2) Compounding Carbon black 120 120 120 120 material Calcium carbonate 50 50 50 50 Zinc oxide 7 7 7 7 Stearic acid 7 1 1 1 Other 5 5 5 5 Vulcanizing Sulfur powder 1.2 1.2 1.2 1.2 agent Sulfur Organic vulcanizing agent 0.6 0.6 0.6 0.6 compound (morpholine-based) Thiazole-based 2 2 2 2 Dithiocarbamate-based 1.4 1.4 1.4 1.4 Sulfenamide-based 0.3 0.3 0.3 0.3 Foaming agent OBSH foaming agent 3.04 3.04 3.04 3.04 Mass ratio Oil/EPM 4.7 only Oil 0.3 0.8 Roll processability X Physical Sound insulation degree 43.1 41.5 42.6 property (dBA) of 0.4 to 10 kHz Specific gravity about 0.7 about 0.7 about 0.7 about 0.7

(28) TABLE-US-00002 TABLE 2 Example No. 12 13 14 15 16 17 18 19 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 55 EPM EPM (1) 15 Compounding Carbon black 120 material Calcium carbonate 50 Zinc oxide 7 Stearic acid 1 1 1 1 2 2 2 2 Fatty acid ester-based 1 2 3 5 0 1 2 3 processing aid Other 4 Vulcanizing Sulfur powder 1.2 agent Sulfur Organic vulcanizing agent 0.6 compound (morpholine-based) Thiazole-based 2 Dithiocarbamate-based 1.4 Sulfenamide-based 0.3 Foaming agent OBSH foaming agent 3.04 Mass ratio Oil/EPM 5.0 Physical Sound insulation degree 42.7 43.0 43.4 43.5 42.9 43.0 43.6 43.3 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 60 59 57 56 60 58 56 55 Whitening test Specific gravity 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Example No. 20 21 22 23 24 25 26 27 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 55 EPM EPM (1) 15 Compounding Carbon black 120 material Calcium carbonate 50 Zinc oxide 7 Stearic acid 2 3 3 3 3 3 5 5 Fatty acid ester-based 5 0 1 2 3 5 0 1 processing aid Other 4 Vulcanizing Sulfur powder 1.2 agent Sulfur Organic vulcanizing agent 0.6 compound (morpholine-based) Thiazole-based 2 Dithiocarbamate-based 1.4 Sulfenamide-based 0.3 Foaming agent OBSH foaming agent 3.04 Mass ratio Oil/EPM 5.0 Physical Sound insulation degree 42.8 43.5 43.5 43.7 43.5 43.6 43.8 43.9 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 55 56 54 54 54 53 55 55 Whitening test Specific gravity 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Example No. 28 29 30 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 55 EPM EPM (1) 15 Compounding Carbon black 120 material Calcium carbonate 50 Zinc oxide 7 Stearic acid 5 5 5 Fatty acid ester-based 2 3 5 processing aid Other 4 Vulcanizing Sulfur powder 1.2 agent Sulfur Organic vulcanizing agent 0.6 compound (morpholine-based) Thiazole-based 2 Dithiocarbamate-based 1.4 Sulfenamide-based 0.3 Foaming agent OBSH foaming agent 3.04 Mass ratio Oil/EPM 5.0 Physical Sound insulation degree 43.7 43.7 44.1 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 53 52 52 Whitening test Specific gravity 0.7 0.7 0.7

(29) TABLE-US-00003 TABLE 3 Example No. 31 32 33 34 35 36 37 38 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 55 EPM EPM (1) 15 Compounding Carbon black 120 material Calcium carbonate 50 Zinc oxide 7 Stearic acid 0 0 0 0 0 1 7 7 Fatty acid ester-based 0 1 2 3 5 0 0 1 processing aid Other 4 Vulcanizing Sulfur powder 1.2 agent Sulfur Organic vulcanizing agent 0.6 compound (morpholine-based) Thiazole-based 2 Dithiocarbamate-based 1.4 Sulfenamide-based 0.3 Foaming agent OBSH foaming agent 3.04 Mass ratio Oil/EPM 5.0 Physical Sound insulation degree 40.3 41.5 41.2 41.5 41.9 42.3 43.5 43.7 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 67 67 64 62 61 61 53 53 Whitening test X X Specific gravity 0.7 0.7 0.7 0.7 0.7 0.7 0.7 0.7 Example No. 39 40 41 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 55 EPM EPM (1) 15 Compounding Carbon black 120 material Calcium carbonate 50 Zinc oxide 7 Stearic acid 7 7 7 Fatty acid ester-based 2 3 5 processing aid Other 4 Vulcanizing Sulfur powder 1.2 agent Sulfur Organic vulcanizing agent 0.6 compound (morpholine-based) Thiazole-based 2 Dithiocarbamate-based 1.4 Sulfenamide-based 0.3 Foaming agent OBSH foaming agent 3.04 Mass ratio Oil/EPM 5.0 Physical Sound insulation degree 43.7 43.5 43.5 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 53 52 52 Whitening test X X X Specific gravity 0.7 0.7 0.7

(30) TABLE-US-00004 TABLE 4 Comparative Comparative Sample name Example 4 Example 42 Example 43 Example 5 Example 44 EPDM Oil-extended EPDM 120 (oil-extended amount of (Polymer 100) extender oil: 20 phr) (Oil 20) Oil Process oil 42 27 27 55 40 EPM EPM (1) 0 15 15 0 15 Compounding Carbon black 102 102 102 84 84 material Calcium carbonate 22 22 22 75 75 Zinc oxide 7 7 7 10 10 Stearic acid 2 2 4 5 5 Fatty acid ester-based 1 1 1 1 1 processing aid Other 2 2 2 5 5 Vulcanizing Sulfur powder 1.2 1.2 1.2 1.2 1.2 agent Sulfur Organic vulcanizing agent 0.6 0.6 0.6 0.6 0.6 compound (morpholine-based) Thiazole-based 2 2 2 2 2 Dithiocarbamate-based 1.4 1.4 1.4 1.4 1.4 Sulfenamide-based 0.3 0.3 0.3 0.3 0.3 Foaming agent OBSH foaming agent 5.85 5.85 5.85 5.85 5.85 Mass ratio Oil/EPM only Oil 3.1 3.1 only Oil 4.0 Physical Sound insulation degree 38.2 38.9 39.6 40.5 41.1 property (dBA) of 0.4 to 10 kHz Mooney viscosity (M1 + 4, 100 C.) 42.7 57.9 53 39.2 51.1 Whitening test Specific gravity 0.4 0.4 0.4 0.5 0.5

(31) Details of the components used herein are as follows. Oil-extended EPDM: trade name Mitsui EPT8120E available from Mitsui Chemicals, Inc. (diene type: ENB, diene content (ratio): 14% by mass, oil-extended amount: 20 phr)

(32) 120 parts by mass of mixed oil-extended EPDM includes 100 parts by mass of EPDM polymer and 20 parts by mass of extender oil. The weight average molecular weight of the extender oil is not disclosed, but is estimated to be 1,500 or less. EPM (1): trade name Mitsui EPT0045 available from Mitsui Chemicals, Inc. (ethylene content (ratio): 51% by mass) EPM (2): trade name Vistalon 404 available from Exxon Mobil Corporation (ethylene content: 45% by mass) Process oil: trade name Diana process oil PS-380 available from Idemitsu Kosan Co., Ltd. (paraffinic mineral oil, molecular weight: 700, kinematic viscosity (100 C.): 30 mm.sup.2/s) Carbon black: SRF, iodine absorption: 20 mg/g, DBP absorption: 115 cm.sup.3/100 g Stearic acid: trade name LUNAC S-50V available from Kao Corporation Fatty acid ester-based processing aid: trade name Emaster 430W available from Riken Vitamin Co., Ltd. Zinc oxide: trade name META Z-102 available from Inoue Calcium Corporation Vulcanizing agent: Sulfur powder Organic vulcanizing agent: trade name VULNOC R (4,4-dithiodimorpholine) available from Ouchi Shinko Chemical Industrial Co., Ltd. Foaming agent: p,p-oxybisbenzenesulfonyl hydrazide (OBSH) foaming agent

(33) The mass ratio oil/EPM is a mass ratio of oil (sum of process oil and extender oil in oil-extended EPDM) to EPM.

(34) The components of the rubber materials in Examples and Comparative Examples were each weighed so as to satisfy each mixing ratio in Tables 1 to 4. The components were kneaded by a Banbury mixer and a roller, extruded by an extruder, and then heated, resulting in vulcanization and foaming. The resultant was molded and processed into a foamed rubber sheet having a thickness of 1.2 mm. Since sulfur in the vulcanizing agent cross-links EPDM but does not cross-link EPM, the foamed rubber sheets in Examples and Comparative Examples contain cross-linked EPDM and uncross-linked EPM.

(35) The rubber materials in Examples and Comparative Examples were subjected to the following evaluations.

(36) 1. Roll Processability (Only in Examples 1 to 11 and Comparative Examples 1 to 3)

(37) When a rubber during roll processing was sufficiently wound around a roll and the processability (kneading property) was favorable, the roll processability was evaluated to be good (). When the rubber slightly floated, the roll processability was evaluated to be fair (). When the rubber severely floated and could not be processed, the roll processability was evaluated to be poor ().

(38) 2. Processability (Mooney Viscosity)

(39) For the rubber materials kneaded (before vulcanization), the Mooney viscosity (ML (1+4) 100 C.) was measured. As the Mooney viscosity is lower, the processability can be evaluated to be more excellent.

(40) For the rubbers (foamed rubber sheets) obtained by molding the rubber materials in Examples and Comparative Examples, the following measurement and evaluation were performed.

(41) 3. Sound Insulation

(42) The produced foamed rubber sheets were each mounted in a jig having an opening area of 10 mm90 mm, and the sound insulation degree (dBA) of sound of 400 Hz to 10,000 Hz was measured in an atmosphere of 23 C. As the sound insulation degree is higher, the sound insulation can be evaluated to be more excellent.

(43) The sound insulation degree to be required varies depending on the kind of rubber product, and the level of the sound insulation degree largely varies depending on the specific gravity of rubber. Therefore, the evaluation of sound insulation was performed by comparison of Examples and Comparative Examples of which the specific gravities were the same.

(44) 4. Whitening Test

(45) For the produced foamed rubber sheets, a high temperature and high humidity test in a closed system was performed. A case where whitening due to bloom was not observed was evaluated to be good (), and a case where whitening was observed was evaluated to be poor ().

(46) 5. Specific Gravity

(47) The specific gravity of each of the produced foamed rubber sheets was measured.

(48) The foamed rubber sheets in Examples 1 to 41 and Comparative Examples 1 to 3 have substantially the same specific gravities of about 0.7 and their forms of the foam are also visually the same. The specific gravities of the foamed rubber sheets in Examples 42 and 43 and Comparative Example 4 were 0.4. The specific gravities of the foamed rubber sheets in Example 44 and Comparative Example 5 were 0.5.

(49) In the foamed rubber sheets in Examples 1 to 11, the sound insulation was improved and the roll processability was good as compared with Comparative Example 1. In Comparative Example 2, roll processing was not performed, and the sound insulation was not examined. In Comparative Example 3, the sound insulation was improved as compared with Comparative Example 1, but the roll processability was insufficient.

(50) In the foamed rubber sheets in Examples 12 to 30, the sound insulation was improved as compared with Comparative Example 1, the Mooney viscosity was sufficiently low, and whitening was not observed.

(51) In the foamed rubber sheets in Examples 31 to 35, despite the fact that no stearic acid is contained, the sound insulation was substantially the same as that in Comparative Example 1. The foamed rubber sheets were evaluated to be good. A reason for slightly high Mooney viscosity is considered to be that the viscosity is not sufficiently decreased even by addition of a fatty acid ester-based processing aid due to the absence of stearic acid. Due to the absence of stearic acid, whitening was not observed.

(52) In the foamed rubber sheet in Example 36, the sound insulation was higher than those in Comparative Example 1 and Example 31. This is considered due to a small amount of stearic acid. A reason for slightly high Mooney viscosity is considered to be that a fatty acid ester-based processing aid is not added and the viscosity is not sufficiently decreased by a small amount of stearic acid. Whitening was not observed.

(53) In the foamed rubber sheets in Examples 37 to 41, the sound insulation was higher than those in Comparative Example 1 and Example 31, and the Mooney viscosity was sufficiently low. Whitening due to bloom of stearic acid was slightly observed.

(54) In the foamed rubber sheets in Examples 42 and 43, the sound insulation was slightly improved as compared with Comparative Example 4. The Mooney viscosity was sufficiently low, and whitening was not observed.

(55) In the foamed rubber sheet in Example 44, the sound insulation was slightly improved as compared with Comparative Example 5. The Mooney viscosity was sufficiently low, and whitening was not observed.

(56) FIG. 1A shows a weather strip 1 for automobiles (cross section), and FIG. 1B shows a hose 2 for feeding fuel, refrigerant, or air for automobiles, which are a molded product formed of the rubber in each of Examples 1 to 44. With the weather strip 1, the sound insulation of sound transmitted through the weather strip 1 is improved. With the hose 2, leakage of flow sound of the fuel, refrigerant, or air in the hose to the exterior can be reduced.

(57) The present invention is not limited to Examples described above, and the present invention can be embodied by appropriate modifications without departing from the spirit of the present invention.

REFERENCE SIGNS LIST

(58) 1 Weather strip 2 Hose