Rubber composition for extruded hoses, and hoses

Abstract

To provide a rubber composition for extruded hoses that exhibits excellent extruded surface (extrudeability) during the extrusion process. [Solution] A rubber composition for extruded hoses containing the following components (A) to (D), wherein component (A) is an ethylene-propylene-diene terpolymer, and %C of component (D) is determined by ndM ring analysis. p The range is 45-72, and %C n The range is 20-40, and %C a A rubber composition for extruded hoses, wherein the ratio is 0 to 10. (A) Rubber component (B) Recycled carbon black (C) Non-recycled carbon black (D) Plasticizer

Description

Technical Field

[0001] The present invention relates to a rubber composition for an extrusion hose suitable for extrusion molding, and a hose made of the rubber composition for an extrusion hose.

Background Art

[0002] In recent years, recycled carbon black has attracted attention from the viewpoints of resource conservation and environmental protection. That is, for the purpose of carbon neutrality (CO2 reduction), it has been considered to replace non-recycled carbon black (virgin carbon black, vCB) with recycled carbon black (rCB) obtained by pyrolyzing waste tires or the like.

[0003] For example, Patent Document 1 describes a rubber composition for tires containing a diene rubber, recycled carbon black, and non-recycled carbon black.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The rubber composition for tires described in Patent Document 1 is suitable for the production of tires. However, when it is used for extrusion molding, since the recycled carbon black has poor interaction (reinforcement) with the rubber interface, cracks occur between the recycled carbon black and the rubber during extrusion molding, and these cracks propagate to form large cracks, resulting in a problem that the extrusion surface deteriorates. This has been clarified by the studies of the present inventors.

[0006] The present invention has been made in view of such circumstances, and provides a rubber composition for an extrusion hose that is excellent in the extrusion surface (extrusion processability) during extrusion processing. [Means for solving the problem]

[0007] The inventors of the present invention conducted extensive research to solve the above problems. In the course of this research, they discovered that by using a plasticizer that satisfies specific conditions among various components, a rubber composition for extruded hoses with excellent extruded surface (extrudeability) during extrusion processing can be obtained.

[0008] The present invention discloses the following inventions [1] to [6], but is not limited to these. [1] In a rubber composition for extruded hoses containing the following components (A) to (D), component (A) is an ethylene-propylene-diene terpolymer, and the %C of component (D) is determined by ndM ring analysis. p The range is 45-72, and %C n The range is 20-40, and %C a A rubber composition for extruded hoses, wherein the ratio is 0 to 10. (A) Rubber component (B) Recycled carbon black (C) Non-recycled carbon black (D) Plasticizer [2] The rubber composition for extruded hoses according to [1], wherein the content of component (B) is 10 to 100 parts by mass per 100 parts by mass of component (A). [3] The rubber composition for extruded hoses according to [1] or [2], wherein the mass ratio (B / C) of component (B) to component (C) is 10 / 90 to 90 / 10. [4] The rubber composition for extruded hoses according to any one of [1] to [3], wherein the total amount of carbon black contained in the above extruded hose rubber composition (the sum of the above components (B) and (C)) is 100 parts by mass or more per 100 parts by mass of the above component (A). [5] The rubber composition for extruded hoses according to any one of [1] to [4], wherein the content of component (D) is 40 to 95 parts by mass per 100 parts by mass of component (A). [6] A hose made of a rubber composition for extruded hoses as described in any of [1] to [5]. [Effects of the Invention]

[0009] According to the present invention, a rubber composition for extruded hoses with excellent extrusion processability can be provided.

[0010] Furthermore, according to one embodiment of the present invention, a rubber composition for extruded hoses that exhibits excellent extrusion processability and excellent bleed resistance can be provided. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram showing an example of a hose according to the present invention. [Modes for carrying out the invention]

[0012] Next, embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described below.

[0013] In this specification, "X and / or Y (where X and Y are any configuration)" means at least one of X and Y, and can mean X only, Y only, or X and Y. Furthermore, in this specification, when we use the expression "X~Y" (where X and Y are any numbers), unless otherwise specified, it includes the meaning of "X or greater and Y or less," as well as "preferably greater than X" or "preferably less than Y." Furthermore, with respect to the numerical ranges described in stages in this specification, the upper or lower limit of one stage of the numerical range can be arbitrarily combined with the upper or lower limit of another stage of the numerical range. Also, within the numerical ranges described in this specification, the upper or lower limit of that numerical range can be replaced with the values ​​shown in the test examples.

[0014] <<Rubber composition for extruded hoses>> The present invention relates to a rubber composition for extruded hoses used in extruders, and provides a rubber composition for extruded hoses that exhibits good extruded surface properties during extrusion molding. Specifically, the present invention provides a rubber composition for extruded hoses (hereinafter sometimes referred to as "the rubber composition") that contains, for example, a rubber component, recycled carbon black, and a specific plasticizer.

[0015] Recycled carbon black is produced by burning carbon black-containing rubber products such as waste tires, industrial conveyor belts, power transmission belts, and rubber hoses. Therefore, in addition to carbon black, it contains approximately 2-20% ash derived from rubber components. This ash is compounded with carbon black in the recycled carbon black, and although its particle size varies, it can be broadly classified into three particle sizes: less than 1 μm, around 10 μm, and over 100 μm. Furthermore, unlike non-recycled carbon black, recycled carbon black does not have functional groups on its surface, resulting in poor interaction with rubber components. Consequently, when recycled carbon black is incorporated into a rubber composition for extruded hoses, the recycled carbon black disperses, but the extruded surface deteriorates.

[0016] In order to solve the above problems, the inventors of the present invention have diligently conducted research focusing on plasticizers to be incorporated into rubber compositions for extruded hoses. As a result, they have discovered that the properties of the plasticizer are a factor that affects the properties of the extruded surface, and have arrived at the present invention. In conventional research and development, no technical concept has yet been reported that improves the deterioration of the extruded surface caused by recycled carbon black by using a specific plasticizer, as in the present invention. Furthermore, no technical concept for suppressing bleeding is known at all. Therefore, the usefulness of the rubber composition for extruded hoses according to the present invention is extremely high. Embodiments of the present invention will be described in detail below.

[0017] [(A) Rubber component] The rubber components used in this rubber composition are not particularly limited, but examples include diene rubbers such as natural rubber (NR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), isoprene rubber (IR), and acrylonitrile-butadiene rubber (NBR), and non-diene rubbers such as ethylene-propylene rubber (EPM), ethylene-propylene-diene ternary copolymer (EPDM), butyl rubber (IIR), and acrylic rubber (ACM). These can be used individually or in combination of two or more.

[0018] Among the rubber components mentioned above, in one example of the embodiments of this rubber composition, ethylene-propylene rubber such as EPDM and EPM is preferred, and EPDM is particularly preferred. Furthermore, in one example of the embodiments of this rubber composition, (A) rubber component is preferably mainly composed of ethylene-propylene rubber, and is particularly preferably mainly composed of EPDM. The term "main component" above refers to a component that accounts for 50% or more by mass of the total rubber components (100% by mass) contained in this rubber composition, preferably 55% or more by mass, more preferably 60% or more by mass, and even more preferably 70% or more by mass. It may also be 80% or more by mass, 90% or more by mass, 95% or more by mass, or even 100% by mass.

[0019] The ethylene content of EPDM is not particularly limited, but is preferably 48-70% by mass, and more preferably 50-62% by mass. The propylene content of EPDM is not particularly limited, but is preferably 22-46% by mass, and more preferably 30-44% by mass.

[0020] The content of the diene monomer used as the third component constituting EPDM is not particularly limited, but is preferably 3 to 11% by mass, and more preferably 3.5 to 6% by mass.

[0021] The diene monomer used as the third component of EPDM is not particularly limited, but diene monomers having 5 to 20 carbon atoms are preferred. Specifically, examples include 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 2,5-dimethyl-1,5-hexadiene, 1,4-octadiene, 1,4-cyclohexadiene, cyclooctadiene, dicyclopentadiene (DCP), 5-ethylidene-2-norbornene (ENB), and 5-butylidene-2-norbornene. These can be used individually or in combination of two or more. Among these, DCP and ENB are preferred.

[0022] Mooney viscosity of EPDM (ML) 1+4 The temperature (125°C) is not particularly limited, but is preferably 30 to 110°C, and more preferably 60 to 90°C.

[0023] Furthermore, in one example of the embodiments of this rubber composition, (A) the rubber component may be mainly composed of acrylonitrile-butadiene rubber (NBR). The meaning of "main component" is the same as described above.

[0024] The amount of acrylonitrile (AN) in NBR is not particularly limited, but is preferably 18 to 50% by mass, and more preferably 20 to 42% by mass.

[0025] NBR Mooney viscosity (ML) 1+4 The temperature (up to 100°C) is not particularly limited, but for example, 40 to 82°C is preferred, more preferably 48 to 80°C, and even more preferably 50 to 78°C.

[0026] (A) The content of the rubber component is not particularly limited, but is, for example, 20% by mass or more, preferably 22% by mass or more, more preferably 22-60% by mass, and may be 24-50% by mass, etc., relative to the rubber composition (100% by mass).

[0027] Furthermore, while there are no particular limitations on the EPDM content, in one example of the embodiments of the present invention, it may be, for example, 20% by mass or more, preferably 22% by mass or more, more preferably 22-60% by mass, and may also be 24-50% by mass, based on the rubber composition (100% by mass).

[0028] Furthermore, while there are no particular limitations on the NBR content, in one example of the embodiments of the present invention, it may be, for example, 30% by mass or more, preferably 35% by mass or more, more preferably 40-80% by mass, relative to the rubber composition (100% by mass), and may also be 40-70% by mass.

[0029] [(B) Recycled carbon black] Recycled carbon black, also known as "rCB (recovered carbon black)," is carbon black obtained by recovering it from raw materials that are waste materials used for recycling. As recycled carbon black, it can be obtained by thermally decomposing waste tires, industrial conveyor belts, power transmission belts, and carbon black-containing rubber products such as rubber hoses using known methods.

[0030] As mentioned above, recycled carbon black contains ash derived from rubber components, etc., and its content is usually 2 to 20% by mass, preferably 5 to 20% by mass, more preferably 10 to 20% by mass, and may also be 15 to 17% by mass, etc. The ash content can be measured by a method in accordance with JIS K6218-2:2005. This ash content is composed of particles compounded with carbon black in the recycled carbon black. While there are no particular limitations on the average particle size of the recycled carbon black, from the viewpoint of significantly achieving the effects of the present invention, for example, 100 to 500 nm is preferred, and more preferably 100 to 300 nm. The average particle size of the carbon black is the number-average particle size and is measured by a transmission electron microscope.

[0031] The amount of DBP (dibutyl phthalate) absorbed by recycled carbon black is not particularly limited, but is, for example, 70 to 170 ml / 100g, preferably 80 to 130 ml / 100g, and more preferably 85 to 105 ml / 100g. The DBP absorption of carbon black is measured in accordance with JIS K6217-4:2017.

[0032] The specific surface area for nitrogen adsorption of recycled carbon black is not particularly limited, but for example, 25 to 100 m². 2 The value is / g, preferably 40-90m 2 / g, more preferably 50-80m 2 The value is / g. The nitrogen adsorption specific surface area is measured, for example, by degassing the sample at 200°C for 15 minutes, and then using a mixed gas (N2: 70%, He: 30%) as the adsorbed gas, with a nitrogen adsorption specific surface area analyzer (e.g., Microdata 4232-II).

[0033] The amount of iodine adsorbed by recycled carbon black is not particularly limited, but is, for example, 25 to 100 g / kg, preferably 30 to 90 g / kg. The amount of iodine adsorbed by carbon black is measured in accordance with JIS K6217-1:2008 (Method A).

[0034] The amount of recycled carbon black is, for example, 5 to 200 parts by mass or 10 to 200 parts by mass per 100 parts by mass of (A) rubber component, preferably 20 to 180 parts by mass, more preferably 30 to 170 parts by mass, even more preferably 40 to 160 parts by mass, and particularly preferably 50 to 150 parts by mass, and may also be 10 to 100 parts by mass, 60 to 120 parts by mass, etc. Furthermore, in one embodiment of the present invention, the recycled carbon black content is, for example, 5 to 100 parts by mass, preferably 10 to 90 parts by mass, more preferably 15 to 80 parts by mass, and even more preferably 20 to 70 parts by mass, per 100 parts by mass of (A) rubber component, and may also be 10 to 100 parts by mass, 20 to 50 parts by mass, etc.

[0035] [(C) Non-recycled carbon black] As an example of an embodiment of the present rubber composition, a rubber composition containing non-recycled carbon black together with the aforementioned recycled carbon black can be mentioned. Non-recycled carbon black is carbon black also referred to as "vCB (Virgin Carbon Black)", which means carbon black directly manufactured from hydrocarbons such as coal as raw materials, that is, carbon black that is not a recycled product.

[0036] Examples of non-recycled carbon black include petroleum-derived carbon black. For example, furnace black (furnace carbon black) such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF; acetylene black (acetylene carbon black); thermal black (thermal carbon black) such as FT and MT; channel black (channel carbon black) such as EPC, MPC, and CC; graphite, etc. These can be used alone or in combination of two or more.

[0037] The DBP (dibutyl phthalate) absorption amount of non-recycled carbon black is not particularly limited, but for example, 40 to 250 ml / 100 g is preferable, 50 to 200 ml / 100 g is more preferable, and 50 to 160 ml / 100 g is particularly preferable. Note that the DBP absorption amount of carbon black is measured in accordance with JIS K6217-4:2017.

[0038] The average particle diameter of non-recycled carbon black is not particularly limited, but for example, 10 to 120 nm is preferable, more preferably 20 to 100 nm, and even more preferably 30 to 70 nm. Note that the average particle diameter of carbon black is the number average particle diameter and is measured by a transmission electron microscope.

[0039] The nitrogen adsorption specific surface area of non-recycled carbon black is not particularly limited, but for example, it is 20 to 140 m 2 / g, preferably 30 to 100 m 2 / g, more preferably 40 to 90 m2 The value is / g. The nitrogen adsorption specific surface area is measured, for example, by degassing the sample at 200°C for 15 minutes, and then using a mixed gas (N2: 70%, He: 30%) as the adsorbed gas, with a nitrogen adsorption specific surface area analyzer (e.g., Microdata 4232-II).

[0040] The amount of iodine adsorbed by non-recycled carbon black is not particularly limited, but for example, it is 20 to 160 mg / g, preferably 30 to 100 mg / g, and more preferably 40 to 90 mg / g. The amount of iodine adsorbed by carbon black is measured in accordance with JIS K6217-1:2008 (Method A).

[0041] As mentioned above, recycled carbon black contains ash derived from rubber components, while non-recycled carbon black contains almost no ash. The ash content in non-recycled carbon black is typically 0.5% by mass or less, 0.3% by mass or less, or 0.1% by mass or less. Ash content can be measured according to the method compliant with JIS K6218-2:2005.

[0042] If the rubber composition contains non-recycled carbon black, in one example of the embodiments of the present invention, the amount is preferably 5 to 200 parts by mass, more preferably 20 to 150 parts by mass, even more preferably 25 to 130 parts by mass, and particularly preferably 30 to 110 parts by mass, per 100 parts by mass of (A) rubber component, and may also be 30 to 90 parts by mass, 30 to 80 parts by mass, etc. Furthermore, in one embodiment of the present invention, the content of non-recycled carbon black is usually 3 to 60 parts by mass, preferably 5 to 70 parts by mass, more preferably 8 to 60 parts by mass, and even more preferably 10 to 50 parts by mass, per 100 parts by mass of (A) rubber component, and may also be 10 to 30 parts by mass, etc.

[0043] Furthermore, when this rubber composition contains non-recycled carbon black, the mass ratio of recycled carbon black to non-recycled carbon black (recycled CB / non-recycled CB) is preferably 10 / 90 to 90 / 10, more preferably 20 / 80 to 85 / 15, even more preferably 30 / 70 to 80 / 20, and may also be 40 / 60 to 75 / 25, etc. When the above ratio is within the above range, the effects of the present invention tend to be more favorably obtained.

[0044] Furthermore, if the rubber composition contains non-recycled carbon black, the total amount of carbon black contained in the rubber composition (total amount of recycled carbon black and non-recycled carbon black) is preferably 100 parts by mass or more, more preferably 110 parts by mass or more, and particularly preferably 120 parts by mass or more, per 100 parts by mass of the rubber component, in one example of the embodiments of the present invention. The upper limit is usually 200 parts by mass or less, preferably 180 parts by mass or less, and more preferably 150 parts by mass or less. Furthermore, if the rubber composition contains non-recycled carbon black, the total amount of carbon black contained in the rubber composition (total amount of recycled carbon black and non-recycled carbon black) is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and particularly preferably 30 parts by mass or more, per 100 parts by mass of the rubber component in one example of the embodiments of the present invention. The upper limit is usually 100 parts by mass or less, preferably 90 parts by mass or less, and more preferably 80 parts by mass or less.

[0045] [(D) Plasticizers] This rubber composition contains a plasticizer that satisfies specific conditions. Specifically, for example, in one embodiment of this rubber composition, the proportion of paraffinic carbon (%C) determined by ndM ring analysis is... p ), the proportion of naphthenic carbon (%C n ), preferably contains a plasticizer in which the proportion of aromatic carbons (%Ca) is within a specific range.

[0046] (Analysis of the ndM ring of plasticizers) In the process of diligently conducting research to improve the deterioration of the extruded surface caused by recycled carbon black contained in the rubber composition for extruded hoses, the inventors focused on the properties of the plasticizer blended into the rubber composition for extruded hoses and conducted further investigations. As a result, they found that the proportion of paraffinic carbon (%C) that constitutes the plasticizer was important. p ), the proportion of naphthenic carbon (%C n ), and learned that the proportion of aromatic carbon (%Ca) is one of the factors that influence the properties of the extruded surface. In other words, the inventors diligently conducted research focusing on the respective blending ratios or balances of paraffinic carbon, naphthenic carbon, and aromatic carbon in plasticizers, and as a result found that in a rubber composition for extruded hoses containing rubber components and recycled carbon black, a good extruded surface can be achieved and bleeding can be suppressed if a plasticizer with the above blending ratios within a specific range is blended. In a rubber composition for extruded hoses containing recycled carbon black, the proportion of paraffinic carbon (%C) determined by ndM ring analysis is... p ), the proportion of naphthenic carbon (%C n The technical concept of improving the deterioration of the extruded surface caused by recycled carbon black, and the technical concept of suppressing bleeding, by setting the proportion of aromatic carbon (%Ca) within a specific range, has not yet been reported in the prior art. This technical concept was discovered for the first time by the present inventors and is extremely useful in extruded hose applications.

[0047] Specifically, in one example of the embodiments of this rubber composition, the plasticizer has a paraffinic carbon content (%Cp) determined by ndM ring analysis that is preferably 45 to 72, and more preferably 50 to 72. The naphthenic carbon content (%Cn) is preferably 20 to 40, and more preferably 20 to 35. The aromatic carbon content (%Ca) is, for example, 0 to 13 or greater than 0 to 13, more preferably 0 to 10, and even more preferably 5 to 10. Furthermore, in the plasticizer used in one embodiment of this rubber composition, the proportion of paraffinic carbon (%Cp) may be, for example, 60-72, 65-72, or 68-72, and the proportion of naphthenic carbon (%Cn) may be, for example, 20-30 or 20-25. Also, the proportion of aromatic carbon (%Ca) may be, for example, 0-8, 1-7, or 2-6. Note that the above paraffinic carbon ratio (%C p ), the percentage of naphthenic carbon atoms (%C n ), the proportion of aromatic carbons (%C a The carbon distribution is determined according to ring analysis (ndM method, ASTM D3238: Standard Test Method for Calculation of Carbon Distribution and Structural Group Analysis of Petroleum Oils by the ndM Method).

[0048] In one example of a preferred embodiment of this rubber composition, %C is determined by ndM ring analysis. p The range is 45-72, and %C n The range is 20-40, and %C a It is particularly preferable to use a plasticizer with a ratio of 0 to 10. That is, while paraffinic carbon blends well with rubber, if its proportion is too high, it negatively affects the dispersibility of recycled carbon black, and crack propagation tends not to be suppressed. Aromatic carbon and naphthenic carbon contribute to dispersibility, but tend to negatively affect bleed resistance. In one example of a preferred embodiment of this rubber composition, the plasticizer mainly consists of paraffinic carbon with an appropriate amount of naphthenic carbon, and is therefore presumed to improve the deterioration of the extruded surface caused by recycled carbon black and effectively suppress bleed. Furthermore, in one example of a preferred embodiment of this rubber composition, the above effects can be achieved even more effectively by including paraffinic carbon as the main component, an appropriate amount of naphthenic carbon, and a small amount of aromatic carbon.

[0049] (Aniline point of plasticizer) Furthermore, as an example of an embodiment of the present invention, in a rubber composition for extruded hoses containing a rubber component and recycled carbon black, by incorporating a plasticizer with an aniline point of 140°C or lower, preferably a plasticizer with an aniline point of 80 to 140°C, a good extruded surface can be achieved, and bleeding tends to be suppressed. The aniline point of the plasticizer can be appropriately set within the above range, but for example, 90 to 140°C is preferred, and the aniline point may also be 100 to 140°C, 110 to 140°C, etc. The above aniline point is measured in accordance with JIS K2256:2013. The aniline point is one of the indicators that reflects the composition of the plasticizer, and is determined by the proportion or balance of paraffinic carbon, naphthenic carbon, and aromatic carbon content.

[0050] (SP value of plasticizer) Furthermore, in one example of the embodiments of this rubber composition, a plasticizer having an SP value within a specific range is preferred.

[0051] Specifically, as an example of an embodiment of the present invention, in a rubber composition for extruded hoses containing a rubber component and both recycled carbon black and non-recycled carbon black, the SP value of component (A) is (A SP ) and the SP value of the plasticizer (D SP ) difference (A SP -D SP If the difference in SP values ​​(A) is within a range of, for example, ±2.0, a good extruded surface can be achieved. SP -D SP ) can be set appropriately within the above range, but for example, ±1.5 is preferred, and ±1.0 or ±0.8 may also be acceptable.

[0052] In one embodiment of the present invention, the plasticizer is the difference in the above SP value (A SP -D SP It is preferable to use a process oil or ether ester plasticizer in which the difference in SP values ​​(A) is within the above range, and among them, it is preferable to use a process oil or ether ester plasticizer in which the difference in SP values ​​(A) is within the above range. SP -D SPEther ester plasticizers in which the above range is present are preferred. Examples of such ether ester plasticizers include plasticizers having both ether and ester bonds in one molecule, specifically, adipate ether ester plasticizers such as bis[2-(2-butoxyethoxy)ethyl] adipate.

[0053] In one embodiment of this rubber composition, the SP value of component (A) is not particularly limited, but for example, it is 7.9 to 8.0. Furthermore, in one embodiment of this rubber composition, the SP value of component (A) is not particularly limited, but may be, for example, 9.0 to 10.5, or 9.4 to 10.5.

[0054] In one embodiment of the present rubber composition, the SP value of (D) the plasticizer is not particularly limited, but is, for example, 6.0 to 8.0, and preferably 6.0 to 7.0. Furthermore, in one example of the embodiments of this rubber composition, the SP value of (D) the plasticizer is not particularly limited, but is, for example, 8.5 to 9.5, and preferably 9.0 to 9.5.

[0055] The SP value, also known as the solubility parameter, is an indicator of a substance's polarity and can be calculated using the following formula (1).

[0056]

number

[0057] Furthermore, if the rubber composition contains multiple types of plasticizers, it is preferable to use the weight-weighted average value for the aniline points of the plasticizers. Also, if the rubber composition contains multiple types of rubber components or multiple types of plasticizers, it is preferable to use the volume-weighted average value for each SP value.

[0058] The content of (D) plasticizer in this rubber composition is not particularly limited, but in one embodiment of the present invention, it is, for example, 10 to 120 parts by mass, preferably 20 to 110 parts by mass, more preferably 30 to 100 parts by mass, and particularly preferably 40 to 95 parts by mass, per 100 parts by mass of (A) rubber component. Alternatively, it may be 40 to 90 parts by mass, 50 to 90 parts by mass, etc. Furthermore, the content of (D) plasticizer in the rubber composition is, in one example of the embodiment of the present invention, for example, 5 to 50 parts by mass, preferably 10 to 45 parts by mass, and more preferably 12 to 40 parts by mass, per 100 parts by mass of (A) rubber component. It may also be 15 to 35 parts by mass, etc.

[0059] (Other ingredients) This rubber composition may contain compounding agents commonly used in the rubber industry, such as vulcanizing agents, vulcanization accelerators, vulcanization aids, anti-aging agents, and fillers (excluding carbon black), to the extent that they do not impair the effects of the present invention. These can be used individually or in combination of two or more.

[0060] [Vulcanizing agent] Examples of vulcanizing agents include sulfur-based vulcanizing agents and peroxide-based vulcanizing agents. These can be used individually or in combination of two or more types.

[0061] Examples of sulfur-based vulcanizing agents include powdered sulfur, precipitated sulfur, colloidal sulfur, surface-treated sulfur, and insoluble sulfur.

[0062] Examples of peroxide-based vulcanizing agents include 2,4-dichlorobenzoyl peroxide, benzoyl peroxide, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, n-butyl-4,4'-di-t-butylperoxyvalerate, dicumyl peroxide, t-butylperoxybenzoate, di-t-butylperoxy-diisopropylbenzene, t-butylcumyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexane, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyn-3, and 1,3-bis-(t-butylperoxy-isopropyl)benzene.

[0063] When a sulfur-based vulcanizing agent is used as the vulcanizing agent, its content is preferably 0.4 to 15 parts by mass, more preferably 0.5 to 10 parts by mass, and may also be 0.5 to 6 parts by mass, per 100 parts by mass of the rubber component (A).

[0064] Furthermore, when a peroxide-based vulcanizing agent is used as the vulcanizing agent, its content is preferably 0.5 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 1.5 to 10 parts by mass, per 100 parts by mass of (A) rubber component.

[0065] [Vulcanization accelerator] The vulcanization accelerator is not particularly limited, but examples include thiram-based vulcanization accelerators such as dibenzothiazole disulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, and tetrabenzylthiuram disulfide; N-oxydiethylene-2-benzothiazolyl sulfenamide, N-cyclohexyl-2-benzothiazolyl sulf Examples include sulfenamide-based vulcanization accelerators such as phenamide, Nt-butyl-2-benzothiazoylsulfenamide, and N,N'-dicyclohexyl-2-benzothiazoylsulfenamide; thiazole-based vulcanization accelerators such as dibenzothiadyl disulfide, 2-mercaptobenzothiazole, 2-mercaptobenzothiazole sodium salt, and 2-mercaptobenzothiazole zinc salt (ZnMBT); dithioate-based vulcanization accelerators such as dibutyldithiocarbamate zinc; and sulfur chloride and sulfur disulfide. These can be used individually or in combination of two or more.

[0066] If the rubber composition contains a vulcanization accelerator, the amount is not particularly limited, but is usually 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of (A) rubber component.

[0067] [Vulcanization aid] While not particularly limited, examples of vulcanization aids include zinc oxide, zinc oxide (ZnO), stearic acid, and magnesium oxide. These can be used individually or in combination of two or more.

[0068] Examples of zinc oxide include zinc oxide type 1, zinc oxide type 2, zinc oxide type 3, and fine zinc oxide.

[0069] If the rubber composition contains a vulcanization aid, the amount is not particularly limited, but is usually 1 to 25 parts by mass, preferably 2 to 10 parts by mass, per 100 parts by mass of (A) rubber component.

[0070] [Filler] The fillers are not particularly limited, but examples include talc, mica, clay, and calcium carbonate. These can be used individually or in combination of two or more.

[0071] If the rubber composition contains a filler, its content is not particularly limited, but is usually 20 to 180 parts by mass, preferably 50 to 160 parts by mass, and more preferably 60 to 120 parts by mass, per 100 parts by mass of (A) rubber component.

[0072] [Anti-aging agent] Examples of anti-aging agents include carbamate-based anti-aging agents, phenylenediamine-based anti-aging agents, phenol-based anti-aging agents, phenylamine-based anti-aging agents, diphenylamine-based anti-aging agents, quinoline-based anti-aging agents, imidazole-based anti-aging agents, and waxes. These can be used individually or in combination of two or more.

[0073] If the rubber composition contains an anti-aging agent, the amount is not particularly limited, but is usually 0.5 to 10 parts by mass, preferably 0.7 to 8 parts by mass, and more preferably 1 to 6 parts by mass, per 100 parts by mass of (A) rubber component.

[0074] [Preparation of this rubber composition] This rubber composition can be prepared, for example, by appropriately blending rubber components, recycled carbon black, a plasticizer, and, if necessary, non-recycled carbon black and the various materials mentioned above, and then kneading them using a kneader, roll, Banbury mixer, or other mixing machine.

[0075] This rubber composition is preferably used as a rubber composition for extruded hoses. The hose made of this rubber composition is not particularly limited in whether it has a single-layer structure or a multi-layer structure with two or more layers laminated together, but it is preferable that at least the innermost layer (or that layer in the case of a single-layer structure) is made of this rubber composition.

[0076] [Hose manufacturing method] The following describes an example of a method for manufacturing a hose made from this rubber composition using an extruder. First, as mentioned above, the rubber component, recycled carbon black, plasticizer, and various other materials as needed are appropriately blended and mixed using a kneader, roll, Banbury mixer, or other mixing machine to prepare the rubber composition. Referring to Figure 1, a hose made of this rubber composition is manufactured by extruding the rubber composition onto a hollow or mandrel using an extrusion molding machine to form an inner rubber layer 11. Next, a reinforcing yarn layer 12 is formed on the outer surface of the inner rubber layer 11 by braiding reinforcing yarns made of various fibers or plated wires such as brass plated wires in a spiral or the like. Then, an outer rubber layer 13 is formed by extruding the rubber composition for forming the outer rubber layer onto the outer surface of the reinforcing yarn layer 12. Finally, a three-layer hose can be manufactured by vulcanizing (steam vulcanization, etc.) this laminate under predetermined conditions (for example, 140-170°C for 10-60 minutes).

[0077] In a hose made of the rubber composition obtained as described above, the thickness of the innermost layer (or the single layer in the case of a single-layer structure) is preferably 0.25 to 10 mm, and more preferably 0.5 to 5 mm. Also, when a rubber outer layer 3 is provided as shown in Figure 1, its thickness is preferably 0.25 to 10 mm, and more preferably 0.5 to 5 mm. Furthermore, the inner diameter of the hose is preferably 5 to 60 mm, and more preferably 10 to 40 mm.

[0078] Furthermore, hoses made from this rubber composition can be suitably used as engine cooling system hoses such as radiator hoses used to connect the engine and radiator in vehicles such as automobiles, heater hoses used to connect the engine and heater core, refrigerant transport hoses for coolers, methanol fuel hoses, hydrogen fuel hoses for fuel cell vehicles, and gasoline fuel hoses. In addition, these hoses can be used not only for automobiles but also for other transport machinery (industrial transport vehicles such as airplanes, forklifts, excavators, and cranes, and railway vehicles, etc.). [Examples]

[0079] Next, we will describe some test examples of the present invention. However, the present invention is not limited to these test examples.

[0080] <Test Example 1> This test example involves recycled carbon black and the proportion of paraffinic carbon within a specific range (%C). p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a This demonstrates that a rubber composition for extruded hoses containing a plasticizer having the following properties exhibits excellent effects in terms of extruded surface characteristics and bleed resistance. First, the following materials were prepared.

[0081] [(A) Rubber component] • Rubber component (EPDM, manufactured by ENEOS Material Co., Ltd., "EP103AF")

[0082] [(B) Recycled carbon black] ·Recycled CB1 (ash content 17% by mass, "P365" manufactured by Taiwan Guantou Technology Co., Ltd.) ·Recycled CB2 (ash content 2% by mass, “Synt CB” manufactured by Syntoil)

[0083] [(C) Non-recycled carbon black] • Non-regenerated CB1 (DBP absorption rate 119 ml / 100 g, nitrogen adsorption specific surface area 90 m²) 2 ( / g, iodine adsorption capacity 92g / kg, manufactured by Cabot Japan, "VULCAN(registered trademark) 3D") • Non-regenerated CB2 (DBP absorption rate 129 ml / 100 g, nitrogen adsorption specific surface area 46 m²) 2 ( / g, iodine adsorption capacity 52g / kg, manufactured by Cabot Japan, "SPHERON(registered trademark) 1420G")

[0084] [(D) Plasticizers] • Plasticizer 1 (Idemitsu Kosan Co., Ltd. Diana Process Oil "PW-380") • Plasticizer 2 (Idemitsu Kosan Co., Ltd. Diana Process Oil "PS-430") • Plasticizer 3 (Idemitsu Kosan Co., Ltd. Diana Process Oil "PW-32") • Plasticizer 4 ("Sansen (registered trademark) 410" manufactured by Japan Sun Oil Co., Ltd.) The properties of plasticizers 1 to 4 are as follows in Table 1. Note that the values ​​in Table 1 are rounded to one decimal place.

[0085] [Table 1]

[0086] [Test Example 1-1] The above materials are blended in the proportions shown in Table 2 below, and further, 1.0 part by mass of vulcanizing agent (SULFAX® T-10 manufactured by Tsurumi Chemical Industry Co., Ltd.), 0.5 parts by mass of vulcanizing accelerator 1 (Suncellar® TT-G manufactured by Sanshin Chemical Industry Co., Ltd.), 0.5 parts by mass of vulcanizing accelerator 2 (Suncellar® TET-G manufactured by the same company), 1.0 part by mass of vulcanizing accelerator 3 (Suncellar® CZ-G manufactured by the same company), 1.0 part by mass of vulcanizing accelerator 4 (Noxellar® DM-P manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and vulcanizing accelerator 5 (manufactured by the same company) A rubber composition for extruded hoses was prepared by mixing 1.0 part by mass of Noxellar (registered trademark) TRA, 5 parts by mass of vulcanization aid 1 (Zinc Oxide Type 2, manufactured by Mitsui Mining & Smelting Co., Ltd.), 1 part by mass of vulcanization aid 2 (Bead Stearic Acid Sakura, manufactured by Nippon Oil & Fats Co., Ltd.), and 70 parts by mass of calcium carbonate (Whiteon (registered trademark) SB, manufactured by Shiraishi Calcium Co., Ltd.) (the above amounts are relative to 100 parts by mass of rubber component (EPDM), and these are collectively referred to as "additional components"). These were then kneaded using a Banbury mixer and an open roll.

[0087] [Test Examples 1-2 to 1-4] The above materials were blended in the proportions shown in Tables 3, 4, or 5, and additional components were added in the same manner as above. These were then kneaded using a Banbury mixer and an open roll to prepare a rubber composition for extruded hoses.

[0088] The rubber composition for extruded hoses obtained in this manner was used for the following evaluations. The results are shown in Tables 2 to 5.

[0089] [Evaluation test of extruded skin] Rubber compositions for extruded hoses were extruded using an extruder equipped with a garbage die at the tip (rotation speed 40 rpm, cylinder head temperature 80°C, head temperature 100°C). The extruded surface of each obtained extruded product was visually inspected according to ASTM D2230-77 Method A (garber die extrusion test), and the surface shape and edge shape were evaluated. Test examples 1-1a, 1-2a, 1-3a, or 1-4a were used as the benchmark (BM). (Evaluation Criteria) A: Both the surface shape and edge shape ranks are equal to or higher than BM (reference), and at least one of the surface shape and edge shape ranks is at least one rank higher than BM (reference). B: At least one of the surface shape and edge shape ranks is one rank or more lower than BM (reference).

[0090] [Breed evaluation test] The extruded samples, as described above, were left to stand at room temperature and humidity (23°C, 55% relative humidity). After that, their surfaces were wiped with filter paper (ADVANTEC 5C 55mm), and the oil-absorbing paper was left to stand for a predetermined period of time before being visually inspected to evaluate its bleed resistance. ○: No discoloration was observed even after leaving it for a week. △: Discoloration was observed after leaving it for one week. ×: Discoloration was observed after leaving it for one day.

[0091] [Table 2]

[0092] [Table 3]

[0093] [Table 4]

[0094] [Table 5]

[0095] As mentioned above, this test example involves recycled carbon black and the proportion of paraffinic carbon within a specific range (%C). p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a This demonstrates that a rubber composition for extruded hoses containing a plasticizer having the following properties exhibits excellent effects in terms of extrusion surface and bleed resistance. As shown in the results of Test Example 1-1 in Table 2, the percentage of paraffinic carbon (%C) p For Test Example 1-1a, which contained 73% plasticizer, the proportion of paraffinic carbon (%C) was compared. p Test Example 1-1b (Plasticizer %C) containing a plasticizer with a plasticizer content of less than 73 p :72), Test Example 1-1c (%C of plasticizer) p :67), and Test Example 1-1d (%C of plasticizer) p In 43), the evaluation level of the extruded surface improved. On the other hand, the plasticizer used in Test Example 1-1d had a naphthenic carbon ratio (%C n ) is 47, the proportion of aromatic carbons (%C a ) was 10, and although the evaluation level of the extruded surface improved compared to Test Example 1-1a, the result was insufficient in terms of bleed resistance. In contrast, Test Example 1-1b (plasticizer %C n :22, %C a :6) and Test Example 1-1c (%C of plasticizer) n :33, %C a :0) also showed good results in terms of bleed resistance, and among them, Test Example 1-1b showed particularly good results in terms of the balance between extruded surface and bleed resistance.

[0096] Test Example 1-2, shown in Table 3, is a test example in which the recycled carbon black used in Test Example 1-1 was changed to a different type of recycled carbon black (recycled CB2). As shown in the results in Table 3, the same results as in Test Example 1-1 were obtained.

[0097] Test Examples 1-3, shown in Table 4, are examples in which the non-recycled carbon black used in Test Example 1-1 was changed to a different type of non-recycled carbon black (non-recycled CB2). As shown in the results in Table 4, the same results as in Test Example 1-1 were obtained.

[0098] Test Examples 1-4, shown in Table 5, are test examples in which the content of the plasticizer added in Test Example 1-1 was changed. As shown in the results in Table 5, the same results as in Test Example 1-1 were obtained.

[0099] Based on the above, in a rubber composition for extruded hoses containing (A) rubber components, (B) recycled carbon black, (C) non-recycled carbon black, and (D) plasticizer, the proportion of paraffinic carbon (%C) within a specific range is determined. p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a Specifically, by using a plasticizer that has ) %C p The range is 45-72, and %C n The range is 20-40, and %C a It has been found that using a plasticizer with a value between 0 and 10 improves the evaluation of the extruded surface and exhibits good bleed resistance.

[0100] As shown in the results of Test Example 1-1 in Table 2, Test Example 1-1b (aniline point of plasticizer: 133.2°C) and Test Example 1-1c (aniline point of plasticizer: 111.1°C) showed improved evaluation levels of extruded surface compared to the BM (reference) Test Example 1-1a (aniline point of plasticizer: 144°C). On the other hand, Test Example 1-1d (aniline point of plasticizer: 71.5°C) showed improved evaluation levels of extruded surface compared to the BM (reference) Test Example 1-1a (aniline point of plasticizer: 144°C), but the results were insufficient in terms of bleed resistance. In contrast, Test Example 1-1b (aniline point of plasticizer: 133.2°C) and Test Example 1-1c (aniline point of plasticizer: 111.1°C) showed good results in terms of bleed resistance.

[0101] <Test Example 2> This test example, similar to the above, uses recycled carbon black and a specific range of paraffinic carbon (%C). p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a This demonstrates that a rubber composition for extruded hoses containing a plasticizer having the following properties exhibits excellent effects in terms of extrusion surface and bleed resistance.

[0102] [Test Example 2-1] The above materials are blended in the proportions shown in Table 6 below, and further, 1.0 part by mass of vulcanizing agent (SULFAX® T-10 manufactured by Tsurumi Chemical Industry Co., Ltd.), 0.5 parts by mass of vulcanizing accelerator 1 (Suncellar® TT-G manufactured by Sanshin Chemical Industry Co., Ltd.), 0.5 parts by mass of vulcanizing accelerator 2 (Suncellar® TET-G manufactured by the same company), 1.0 part by mass of vulcanizing accelerator 3 (Suncellar® CZ-G manufactured by the same company), 1.0 part by mass of vulcanizing accelerator 4 (Noxellar® DM-P manufactured by Ouchi Shinko Chemical Industry Co., Ltd.), and vulcanizing accelerator 5 (manufactured by the same company) A rubber composition for extruded hoses was prepared by mixing 1.0 part by mass of Noxellar (registered trademark) TRA, 5 parts by mass of vulcanization aid 1 (Zinc Oxide Type 2, manufactured by Mitsui Mining & Smelting Co., Ltd.), 1 part by mass of vulcanization aid 2 (Bead Stearic Acid Sakura, manufactured by Nippon Oil & Fats Co., Ltd.), and 70 parts by mass of calcium carbonate (Whiteon (registered trademark) SB, manufactured by Shiraishi Calcium Co., Ltd.) (the above amounts are relative to 100 parts by mass of rubber component (EPDM), and these are collectively referred to as "additional components"). These were then kneaded using a Banbury mixer and an open roll.

[0103] The rubber composition for extruded hoses obtained in this manner was used for the evaluation described above. The results are shown in Table 6. Test example 2-1a was used as the benchmark (BM).

[0104] [Table 6]

[0105] As mentioned above, this test example involves recycled carbon black and the proportion of paraffinic carbon within a specific range (%C). p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a This demonstrates that a rubber composition for extruded hoses containing a plasticizer having the following properties exhibits excellent effects in terms of extrusion surface and bleed resistance. As shown in the results of Test Example 2-1 in Table 6, the percentage of paraffinic carbon (%C) p For Test Example 2-1a, which contained 73% plasticizer, the proportion of paraffinic carbon (%C) was compared. pTest Example 2-1b (Plasticizer %C) containing a plasticizer with a plasticizer content of less than 73 p :72), Test Example 2-1c (%C of plasticizer) p In :43), the evaluation level of the extruded surface improved. On the other hand, the plasticizer used in Test Example 2-1c had a naphthenic carbon ratio (%Cn) of 47 and aromatic carbon ratio (%Ca) of 10. Although the evaluation level of the extruded surface improved compared to Test Example 2-1a, the result was insufficient in terms of bleed resistance. In contrast, in Test Example 2-1b (plasticizer %C n :22, %C a :6) also showed good results in terms of bleed resistance.

[0106] Based on the above, in a rubber composition for extruded hoses containing (A) rubber components, (B) recycled carbon black, and (D) plasticizer, the proportion of paraffinic carbon (%C) within a specific range is determined. p ), the proportion of naphthenic carbon (%C n ), the proportion of aromatic carbons (%C a By using a plasticizer that has ) , specifically, for example %C p The range is 45-72, and %C n The range is 20-40, and %C a It has been found that using a plasticizer with a value between 0 and 10 improves the evaluation of the extruded surface and exhibits good bleed resistance.

[0107] <Test Example 3> This test example demonstrates that rubber compositions for extruded hoses containing recycled carbon black and plasticizers with a specific SP value range exhibit excellent results in evaluating the extruded surface. First, the following materials were further prepared.

[0108] [(A) Rubber component] • Rubber component (SP value: 10.3, NBR, manufactured by ARLANXEO, Verbenain "3965F") [(C) Non-recycled carbon black] • Non-regenerated CB3 (DBP absorption rate 115 ml / 100 g, nitrogen adsorption specific surface area 42 m²) 2 / g, iodine adsorption capacity 44g / kg, manufactured by Tokai Carbon Co., Ltd., Seast (registered trademark) SO) [(D) Plasticizers] • Plasticizer 5 (SP value: 9.2, manufactured by ADEKA, Adekaiser® RS-107)

[0109] [Test Example 3-1] The above materials were blended in the proportions shown in Table 7 below. Furthermore, 0.5 parts by mass of vulcanizing agent (Sunmix® S-80NBR, manufactured by Sanshin Chemical Industry Co., Ltd.), 2.5 parts by mass of vulcanizing agent (Sunmix® CZ-80NBR, manufactured by the same company), 2.0 parts by mass of vulcanization accelerator 1 (Suncellar® TT-PTC, manufactured by the same company), 4 parts by mass of vulcanization aid 1 (Zinc Oxide Type 2, manufactured by Mitsui Mining & Smelting Co., Ltd.), 1 part by mass of vulcanization aid 2 (Bead Stearic Acid Sakura, manufactured by Nippon Oil & Fats Co., Ltd.), 2 parts by mass of antioxidant (3C), and 2 parts by mass of antioxidant (TMQ) were added (the above amounts are per 100 parts by mass of rubber component (NBR)). These were then kneaded using a Banbury mixer and an open roll to prepare a rubber composition for extruded hoses.

[0110] The rubber composition for extruded hoses obtained in this manner was used to evaluate the extruded surface in the same manner as described above. The results are shown in Table 7 below. Test Example 3-1a was used as the benchmark (BM).

[0111] [Table 7]

[0112] As shown in Table 7, first, from the results of Test Examples 3-1a and 3-1b, it was confirmed that the rubber composition for extruded hoses containing only non-recycled carbon black had superior extruded surface quality compared to the rubber composition for extruded hoses containing only recycled carbon black. In other words, it was confirmed that recycled carbon black caused deterioration of the extruded surface quality. Next, as shown in the results in Table 7, in Test Example 3-1c, a rubber composition for extruded hoses using both non-recycled and recycled CB, in which a plasticizer with a difference of 2.3 from the SP value of the rubber component was added, the extrusion processability decreased, and extrusion processing became impossible. On the other hand, in Test Example 3-1d, a rubber composition for extruded hoses using both non-recycled and recycled CB, which incorporated a plasticizer with a difference of 1.2 from the SP value of the rubber component, the extruded processability was good, and the result was equivalent to that of Test Example 3-1a, which did not contain recycled CB. In other words, it was confirmed that Test Example 3-1d, despite containing recycled CB, had the same excellent extruded surface as Test Example 3-1a, which did not contain recycled CB. Furthermore, Test Example 3-1d, a rubber composition for extruded hoses using both recycled and non-recycled CB, which incorporated a plasticizer with a difference of 1.2 from the SP value of the rubber component, also showed good results in terms of bleed resistance.

[0113] Based on the above, a rubber composition for extruded hoses containing (A) rubber component, (B) recycled carbon black, (C) non-recycled carbon black, and (D) plasticizer, wherein the SP value of component (A) is SP ) and the SP value of the plasticizer (D SP ) difference (A SP -D SP If the value is within a specific range (e.g., ±2.0), it is found that the evaluation of the extruded surface is improved, and good bleed resistance is exhibited.

[0114] While the above test examples illustrate specific embodiments of the present invention, these examples are merely illustrative and should not be interpreted restrictively. Various modifications that would be obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0115] For example, the present invention also discloses the following inventions, but is not limited to them. [I] A rubber composition for extruded hoses containing the following components (A), (B), and (D), wherein the aniline point of component (D) is 140°C or lower, preferably 80 to 140°C. (A) Rubber component (B) Recycled carbon black (D) Plasticizer [II] Furthermore, the rubber composition for extruded hoses described in [I] contains (C) non-recycled carbon black. [III] In a rubber composition for extruded hoses containing the following components (A), (B), and (D), the %C of component (D) is determined by ndM ring analysis. p The range is 45-72, and %C n The range is 20-40, and %C a A rubber composition for extruded hoses, wherein the ratio is 0 to 10. (A) Rubber component (B) Recycled carbon black (D) Plasticizer [IV] In a rubber composition for extruded hoses containing the following components (A) to (D), component (A) is an ethylene-propylene-diene terpolymer, and the SP value of component (A) is (A SP ) and the SP value of the plasticizer (D SP A rubber composition for extruded hoses, wherein the difference between ) is ±2.0, preferably ±1.0. (A) Rubber component (B) Recycled carbon black (C) Non-recycled carbon black (D) Plasticizer [V] The rubber composition for extruded hoses according to any one of [I] to [IV], wherein the above component (A) is at least one of ethylene-propylene-diene terpolymer or acrylonitrile-butadiene rubber. [Industrial applicability]

[0116] The rubber composition for extruded hoses of the present invention can be suitably used as hoses for automobiles, such as radiator hoses used to connect the engine and radiator in vehicles such as automobiles, heater hoses used to connect the engine and heater core, refrigerant transport hoses for coolers, methanol fuel hoses, hydrogen fuel hoses for fuel cell vehicles, and gasoline fuel hoses. Furthermore, these hoses can be used not only for automobiles but also for other transport machinery (industrial transport vehicles such as airplanes, forklifts, excavators, and cranes, and railway vehicles). [Explanation of symbols]

[0117] 11. Inner rubber layer 12 Reinforcement thread layer 13. Outer rubber layer

Claims

1. In a rubber composition for extruded hoses containing the following components (A) to (D), component (A) is acrylonitrile-butadiene rubber, and the SP value of component (A) is ＳＰ ) and the SP value of component (D) ＳＰ A rubber composition for extruded hoses, wherein the difference between the values ​​is ±2.

0. (A) Rubber component (B) Recycled carbon black (C) Non-recycled carbon black (D) Plasticizer

2. The rubber composition for extruded hoses according to claim 1, wherein the content of component (B) is 5 to 100 parts by mass per 100 parts by mass of component (A).

3. The rubber composition for extruded hoses according to claim 1 or 2, wherein the content of component (C) is 3 to 60 parts by mass per 100 parts by mass of component (A).

4. The rubber composition for extruded hoses according to claim 1 or 2, wherein the total amount of carbon black contained in the above extruded hose rubber composition (the sum of the above components (B) and (C)) is 20 to 100 parts by mass per 100 parts by mass of component (A).

5. The rubber composition for extruded hoses according to claim 1 or 2, wherein the content of component (D) is 5 to 50 parts by mass per 100 parts by mass of component (A).

6. The rubber composition for extruded hoses according to claim 1 or 2, wherein the above component (D) is an ether ester plasticizer.

7. A hose comprising the rubber composition for extruded hoses described in claim 1 or 2.

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