Rubber composition and hose

Abstract

The purpose of the present invention is to provide: a rubber composition which has excellent elongation at break, hardness, and ozone resistance after being cured; and a hose. The present invention is a rubber composition and a hose formed using the rubber composition, the rubber composition containing a rubber component, carbon black, and sulfur, the rubber component containing 40 mass% or more of an ethylene-propylene-non-conjugated diene copolymer, the diene content in the copolymer being 6 mass% or more, and the content of sulfur in the ethylene-propylene-non-conjugated diene copolymer being 10 mass% or more. The content of the ethylene-ethylene chain structure is 35.0 mol% or more.

Description

Technical Field

[0001] The present invention relates to a rubber composition and a hose. Background Art

[0002] Conventionally, a rubber composition containing an ethylene-propylene-non-conjugated diene copolymer or the like has been proposed.

[0003] For example, Patent Document 1 describes a fuel cell sealing member that is used to seal a component of a fuel cell and is composed of a crosslinked body of a rubber composition, wherein the rubber composition contains the following (A) and (B).

[0004] (A) A rubber component composed of at least one of ethylene-propylene rubber and ethylene-propylene-diene rubber, wherein the ethylene-ethylene double chain distribution is 29 mol % or less.

[0005] (B) A cross-linking agent composed of an organic peroxide.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2014-192107 Summary of the invention

[0009] Problems to be solved by the invention

[0010] On the one hand, when a rubber composition containing an ethylene-propylene-non-conjugated diene copolymer or the like is used as a rubber composition for a hose, a cured product obtained from the rubber composition is required to have high elongation at break (for improving the flexibility of the hose and the workability of hose installation) and high hardness (for improving the installability of metal parts). However, high elongation at break and high hardness of the cured product are contradictory phenomena, and it is difficult to simultaneously obtain both at a high level.

[0011] Furthermore, when the rubber composition is used for an outer layer of a hose, the outer layer of the hose is required to have ozone resistance.

[0012] The present inventors, with reference to Patent Document 1, used ethylene-propylene-diene rubber having a low ratio of ethylene-ethylene double chain distribution, vulcanized a rubber composition containing the ethylene-propylene-diene rubber, carbon black and sulfur to obtain a cured product, and evaluated the cured product. The results showed that the cured product may not meet the elongation at break, hardness or ozone resistance required for the hose.

[0013] Therefore, an object of the present invention is to provide a rubber composition having excellent elongation at break, hardness and ozone resistance after being cured.

[0014] In addition, an object of the present invention is to provide a hose.

[0015] Means used to solve problems

[0016] The present inventors have conducted intensive studies to solve the above-mentioned problems and have found that the desired effect can be obtained by using a rubber composition containing a rubber component, carbon black and sulfur, thereby completing the present invention, wherein the rubber component contains an ethylene-propylene-non-conjugated diene copolymer in a specific amount, and the copolymer has a specific amount of diene and an ethylene-ethylene chain structure in a specific amount.

[0017] According to Patent Document 1, if the double chain distribution of ethylene-ethylene in ethylene-propylene-diene rubber or the like exceeds 29 mol%, the ethylene chain becomes longer, orients the polymer main chain and easily forms a crystal structure. It is therefore predicted that when an ethylene-propylene-diene rubber having a double chain distribution of ethylene-ethylene exceeding 29 mol% is used, the elongation at break of the obtained cured product is lower than when an ethylene-propylene-diene rubber having a double chain distribution of ethylene-ethylene less than the above value is used.

[0018] However, the present inventors have found that, contrary to the above prediction, the elongation at break is increased by setting the content of the ethylene-ethylene chain structure in the ethylene-propylene-non-conjugated diene copolymer to 35.0 mol% or more.

[0019] The present invention has been accomplished based on the above findings and the like, and specifically, is an invention that solves the above-mentioned problems by the following configurations.

[0020] [1] A rubber composition comprising: a rubber component comprising 40% by mass or more of an ethylene-propylene-non-conjugated diene copolymer, wherein the amount of diene in the copolymer is 6% by mass or more and the content of the ethylene-ethylene chain structure is 35.0 mol% or more;

[0021] Carbon black; and

[0022] sulfur.

[0023] [2] The rubber composition according to [1], wherein the molar ratio of the ethylene-ethylene chain structure to the ethylene-propylene chain structure in the ethylene-propylene-non-conjugated diene copolymer is 1.0 or more.

[0024] [3] The rubber composition according to [1] or [2], wherein the entire amount of the rubber component is the ethylene-propylene-non-conjugated diene copolymer.

[0025] [4] The rubber composition according to any one of [1] to [3], wherein the content of the carbon black is 70 parts by mass or more per 100 parts by mass of the rubber component,

[0026] The sulfur content is 0.65 parts by mass or more relative to 100 parts by mass of the rubber component.

[0027] [5] The rubber composition according to any one of [1] to [4], which is used for a hose.

[0028] [6] A hose formed using the rubber composition according to any one of [1] to [4].

[0029] [7] The hose according to [6], which is used for an air conditioner.

[0030] [8] The hose according to [6] or [7], which has an outermost layer formed using the rubber composition.

[0031] Effects of the Invention

[0032] According to the present invention, there can be provided a rubber composition having excellent elongation at break, hardness and ozone resistance after being cured, and a hose formed using the rubber composition. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic perspective view showing an example of the hose of the present invention by cutting through each layer. DETAILED DESCRIPTION

[0034] The present invention is described in detail below.

[0035] In the present specification, a numerical range expressed using "to" means a range including the numerical values ​​described before and after "to".

[0036] In the present specification, unless otherwise specified, each component may be used alone or in combination of two or more substances corresponding to the component. When a component includes two or more substances, the content of the component means the total content of the two or more substances.

[0037] The method for producing each component used in the present invention is not particularly limited, and for example, conventionally known methods can be used.

[0038] In this specification, at least one of the elongation at break, hardness, and ozone resistance being more excellent may be referred to as "the effect of the present invention being more excellent."

[0039] [Rubber composition]

[0040] The rubber composition of the present invention contains:

[0041] A rubber component containing 40% by mass or more of an ethylene-propylene-non-conjugated diene copolymer, wherein the amount of diene in the copolymer is 6% by mass or more and the content of the ethylene-ethylene chain structure is 35.0 mol% or more;

[0042] Carbon black; and

[0043] sulfur.

[0044] In this specification, an ethylene-propylene-non-conjugated diene copolymer having a diene amount and an ethylene-ethylene chain structure content in the above-mentioned specific amounts is also referred to as a "specific EPDM".

[0045] In addition, specific EPDM and ethylene-propylene-non-conjugated diene copolymers other than specific EPDM are also collectively referred to as "EPDM".

[0046] EPDM is a copolymer containing a structural unit derived from ethylene, a structural unit derived from propylene, and a structural unit derived from a non-conjugated diene.

[0047] Since the rubber composition of the present invention has such a configuration, it is considered that the desired effect can be obtained. Although the reason is not clear, it is roughly estimated as follows.

[0048] That is, since crystallinity can be imparted by making the content of the ethylene-ethylene chain structure of the specific EPDM 35.0 mol% or more, it is believed that the hardness of the cured product obtained by curing the rubber composition of the present invention is improved. On the other hand, since the elongation at break of the cured product is affected by the structure of the specific EPDM during elongation, the crystallinity of the ethylene of the specific EPDM is eliminated during elongation, and the non-conjugated diene component of the specific EPDM is made to be 6% by mass or more, partial crosslinking with the conjugated diene component only through sulfur can be achieved, and it is believed that high elongation at break is excellent. The specific EPDM has no double bonds on the main chain, so it has high weather resistance.

[0049] Hereinafter, each component contained in the rubber composition of the present invention will be described in detail.

[0050] <Rubber ingredients>

[0051] In the rubber composition of the present invention, the rubber component contains an ethylene-propylene-non-conjugated diene copolymer (specific EPDM) having a diene amount of 6 mass % or more and an ethylene-ethylene chain structure content of 35.0 mol % or more.

[0052] The rubber composition of the present invention contains specific EPDM, thereby achieving excellent effects of the present invention.

[0053] <Specific EPDM>

[0054] The specific EPDM contained in the present invention is an ethylene-propylene-non-conjugated diene copolymer having a diene amount of 6% by mass or more and an ethylene-ethylene chain structure content of 35.0 mol% or more.

[0055] The ethylene and propylene constituting the specific EPDM are not particularly limited.

[0056] <Non-conjugated diene>

[0057] The non-conjugated diene constituting the specific EPDM is a compound having two double bonds which are not conjugated.

[0058] Examples of the non-conjugated diene include non-conjugated dienes with a chain structure (without a cyclic structure) such as 1,4-hexadiene, and non-conjugated dienes with a cyclic structure (which may further have a chain structure) such as 5-ethylidene-2-norbornene and 5-vinyl-2-norbornene. Among them, the non-conjugated diene is preferably a cyclic non-conjugated diene, and more preferably 5-ethylidene-2-norbornene (ENB) and 5-vinyl-2-norbornene.

[0059] <Diene Amount>

[0060] The diene amount of the specific EPDM is 6% by mass or more.

[0061] In the present invention, the diene amount means the content of the structural unit derived from the non-conjugated diene which the specific EPDM has.

[0062] In the present invention, the diene amount of the specific EPDM is 6% by mass or more in the specific EPDM.

[0063] From the viewpoint of achieving more excellent effects of the present invention, the diene content of the specific EPDM is preferably 6 to 12% by mass, more preferably 6.5 to 10.0% by mass, in the specific EPDM.

[0064] <Ethylene-ethylene chain structure>

[0065] Typically, in a polymer, consecutive units of two monomers are called a dyad.

[0066] Examples of the binary group that EPDM may have include an ethylene-ethylene chain structure, an ethylene-propylene chain structure, and a propylene-propylene chain structure.

[0067] Certain EPDM has an ethylene-ethylene chain structure.

[0068] The ethylene-ethylene chain structure is a structure (unit) in which two ethylene repeating units appear consecutively.

[0069] <Content of Ethylene-Ethylene Chain Structure (EE Amount)>

[0070] The content of the ethylene-ethylene chain structure (hereinafter, also referred to as "EE content") is 35.0 mol% or more.

[0071] From the viewpoint of achieving more excellent effects of the present invention, the EE amount is preferably 35.0 to 65.0 mol %, more preferably 45.0 to 55.0 mol %.

[0072] (Based on the content of ethylene-ethylene chain structure (EE amount))

[0073] It should be noted that in the present invention, the content of the ethylene-ethylene chain structure (EE amount) is a percentage based on the total amount (mol) of the content of the ethylene-ethylene chain structure (EE amount), the content of the ethylene-propylene chain structure (EP amount) and the content of the propylene-propylene chain structure (PP amount). The same is true for the EP amount and the PP amount.

[0074] (Ethylene-propylene chain structure)

[0075] The specific EPDM may further have an ethylene-propylene chain structure.

[0076] The ethylene-propylene chain structure means a structure (unit) in which one ethylene repeating unit and one propylene repeating unit appear continuously in EPDM.

[0077] From the viewpoint of achieving more excellent effects of the present invention, the content of the ethylene-propylene chain structure (EP amount) is preferably 30.0 to 60.0 mol%, more preferably 40.0 to 50.0 mol%.

[0078] (Propylene-propylene chain structure)

[0079] The specific EPDM may further have a propylene-propylene chain structure.

[0080] The propylene-propylene chain structure means a structure (unit) in which two propylene repeating units appear continuously in EPDM.

[0081] From the viewpoint of achieving more excellent effects of the present invention, the content of the propylene-propylene chain structure (PP amount) is preferably 5.0 to 35.0 mol%, more preferably 5.0 to 15.0 mol%.

[0082] (EE amount / EP amount)

[0083] From the viewpoint of achieving more excellent effects of the present invention, in the specific EPDM, the molar ratio of the ethylene-ethylene chain structure to the ethylene-propylene chain structure (EE amount / EP amount) is preferably 1.0 or more, more preferably 1.1 to 1.5 or more.

[0084] (Calculation of diene content, EE content, etc. of EPDM)

[0085] In the present invention, the diene amount, EE amount, EP amount and PP amount of EPDM can be measured by isotope carbon nuclear magnetic resonance method ( 13 C-NMR method) was measured, quantified and calculated using the following methods.

[0086] ( 13 C-NMR analysis)

[0087] 13 C-NMR was measured by the inversion gated decoupling method under the condition of 2048 accumulation times (2 hours).

[0088] As a 13 For the C-NMR measurement, a sample prepared by adding deuterated chloroform to EPDM (before vulcanization) to cause the EPDM to swell was used.

[0089] Chemical shift is the change of deuterated chloroform 13 The C signal was set to 77ppm, and the others 13 The chemical shift of the C signal is based on this.

[0090] (Calculation of Diene Amount)

[0091] Depend on 13 The total integrated value of all peaks in the integration range of C-NMR from 51 ppm to 19 ppm (based on mass ratio) and 13 The integral range of C-NMR was the integral value of the peak in the range of 42.00 ppm to 40.60 ppm (based on mass ratio), and the diene amount in EPDM was calculated by the following formula.

[0092] Diene amount (mass %) = A / B × 100

[0093] A: The integrated value of the peak in the integration range of 42.00ppm to 40.60ppm (based on mass ratio)

[0094] B: Total integrated value of all peaks in the integration range of 51ppm to 19ppm (mass ratio basis) (calculation of EE amount, etc.)

[0095] exist 13 In C-NMR, the peak area is integrated within the following integration ranges (ppm), and the EE amount, EP amount, and PP amount are calculated by the following formula using the obtained integrated values. It should be noted that each integrated value used in the calculation of the EE amount, etc., is a molar ratio basis relative to the total integrated value of all chemical shifts contained in the 19-51 ppm region (however, the total integrated value does not include the integrated value of the peak attributed to the structure derived from the conjugated diene (for example, derived from ENB)).

[0096] EE amount (mol%)=(9)×0.5+0.25×(8)+(11)×0.5

[0097] The above (9) represents the integrated value (based on molar ratio) of the peak area in the integration range of 30.68 to 30.00 ppm.

[0098] The above (8) represents the integrated value (based on molar ratio) of the peak area in the integration range of 31.00 to 30.68 ppm.

[0099] The above (11) represents the integrated value (based on molar ratio) of the peak area in the integration range of 27.80 to 27.43 ppm.

[0100] EP amount (mol%) = (2)

[0101] The above (2) represents the integrated value (based on molar ratio) of the peak area in the integration range of 39.80 to 35.60 ppm.

[0102] PP amount (mol%) = (1) + (E1) - 4 × (E2)

[0103] The above (1) represents the integrated value (based on molar ratio) of the peak area in the integration range of 49.00 to 42.00 ppm.

[0104] The above (E1) represents the integrated value of the peak area in the integration range of 51.00 to 49.00 ppm (based on molar ratio).

[0105] The (E2) represents the integrated value (based on molar ratio) of the peak area in the integration range of 42.00 to 40.60 ppm.

[0106] Symbols (E1) to (11) indicating the integrated values ​​of the peak areas in each integration range, the attribution in each integration range, and each integration range (ppm) are summarized below.

[0107] Symbol: Attribution: Integration range (ppm)

[0108] (E1): ENB (C1E): 51.00~49.00ppm

[0109] (1): Sαα+ENB(C5+C6+C1Z): 49.00~42.00ppm

[0110] (E2): ENB (C4): 42.00~40.60ppm

[0111] (2): Sαγ+Sαδ: 39.80~35.60ppm

[0112] (8): Sγδ: 31.00~30.68ppm

[0113] (9): Sδδ: 30.68~30.00ppm

[0114] (11): Sβγ: 27.80~27.43ppm

[0115] ENB is 5-ethylidene-2-norbornene.

[0116] In addition, regarding the above attribution, S means methylene. The Greek letter indicates the position of the shortest methylene carbon atom located between two carbon atoms bonded by a methyl group on the main chain of EPDM, and the adjacent carbon atom to the carbon atom bonded by the methyl group is set as α. Examples of carbon notation are shown below.

[0117] [Chemical formula 1]

[0118]

[0119] Regarding the attribution of EPDM, calculation of monomer ratio, binary ratio, etc., for example, the following documents can be referred to.

[0120] 1. Monomer composition and sequence structure analysis (NMR) of ethylene-propylene elastomer (EPDM) Tosoh technical report: No.T1913 / 2019.12.4

[0121] 2.Determination of Monomer Sequence Distribution in EPDM by13C-NMR:ThirdMonomer Effects[Journal ofAppliedPolymer Science,Vol.71,523-530(1999)]

[0122] 3. US 9,543,596 B2

[0123] (Weight average molecular weight and molecular weight distribution of specific EPDM)

[0124] From the viewpoint of achieving more excellent effects of the present invention, the weight average molecular weight (Mw) of the specific EPDM is preferably 450,000 or less, and more preferably 300,000 to 450,000.

[0125] From the viewpoint of achieving more excellent effects of the present invention, the molecular weight distribution (Mw / Mn) of the specific EPDM is preferably 8.0 to 2.0, more preferably 2.0 to 2.8.

[0126] In this specification, the weight average molecular weight, number average molecular weight and molecular weight distribution of EPDM are standard polystyrene conversion values ​​based on the measured values ​​obtained by gel permeation chromatography (GPC).

[0127] The measurement conditions of the weight average molecular weight of EPDM and the like are as follows.

[0128] ·Measurement instrument: HLC-8020 (manufactured by Tosoh Corporation)

[0129] Column: Two GMH-HR-H (manufactured by Tosoh Corporation) connected in series

[0130] Detector: Differential refractometer RI-8020 (manufactured by Tosoh Corporation)

[0131] ·Eluent: Tetrahydrofuran

[0132] Column temperature: 40°C

[0133] <Specific EPDM content>

[0134] In the present invention, the rubber component contains the specific EPDM in an amount of 40% by mass or more in the rubber component.

[0135] When the content of the specific EPDM is 40% by mass or more in the rubber component, the effects of the present invention (particularly ozone resistance) become excellent.

[0136] From the viewpoint of achieving more excellent effects of the present invention, the rubber component preferably contains the specific EPDM in an amount of 90 to 100% by mass of the rubber component, and more preferably the entire amount of the rubber component is the specific EPDM.

[0137] When the rubber component further contains a rubber component (other rubber component) other than the specific EPDM, the other rubber component is not particularly limited. For example, diene rubbers can be listed, and more specifically, aromatic ethylene-diene copolymers such as natural rubber, butadiene rubber, and styrene-butadiene rubber can be listed.

[0138] When the rubber component further contains another rubber component, from the viewpoint of further improving the effects of the present invention (particularly ozone resistance), the other rubber component preferably contains styrene-butadiene rubber (SBR).

[0139] From the viewpoint of achieving more excellent effects of the present invention, the content of other rubber components is preferably 0 to 60% by mass, more preferably 0 to 10% by mass, and even more preferably 0% by mass in the rubber component.

[0140] <Carbon Black>

[0141] The rubber composition of the present invention contains carbon black.

[0142] (iodine adsorption)

[0143] From the viewpoint of achieving more excellent effects of the present invention, the iodine adsorption amount of carbon black is preferably 10 to 50 mg / g, more preferably 15 to 50 mg / g.

[0144] The iodine adsorption amount of carbon black can be measured in accordance with JIS K6217-1:2008.

[0145] (Nitrogen adsorption specific surface area)

[0146] From the viewpoint of achieving a more excellent effect of the present invention, the nitrogen adsorption specific surface area (N2SA) of carbon black is preferably 0 to 130 m 2 / g, more preferably 20 to 50 m 2 / g.

[0147] The nitrogen adsorption specific surface area of ​​carbon black can be measured in accordance with JIS K6217-2:2008.

[0148] (Oil absorption of dibutyl phthalate)

[0149] From the viewpoint of achieving more excellent effects of the present invention, the dibutyl phthalate (DBP) oil absorption of carbon black is preferably 0 to 140 ml / 100 g, more preferably 0 to 130 ml / 100 g, and even more preferably 40 to 130 ml / 100 g.

[0150] The DBP oil absorption of carbon black can be measured in accordance with JIS K6217-4:2008.

[0151] (Types of Carbon Black)

[0152] From the viewpoint of making the effect of the present invention more excellent, the carbon black preferably comprises at least one selected from the group consisting of SAF, ISAF, HAF, FEF, GPF, SRF, FT and MT carbon black; more preferably comprises at least one selected from the group consisting of FEF, GPF, SRF, FT and MT carbon black; further preferably comprises FEF and / or SRF carbon black.

[0153] (Carbon black content)

[0154] From the viewpoint of achieving more excellent effects of the present invention, the content of carbon black is preferably 70 parts by mass or more, more preferably 70 to 100 parts by mass, based on 100 parts by mass of the rubber component.

[0155] <Sulfur>

[0156] The rubber composition of the present invention contains sulfur.

[0157] The sulfur is not particularly limited as long as it can be used for vulcanization of rubber, and examples thereof include conventionally known sulfurs.

[0158] The form of sulfur is not particularly limited, and examples thereof include oil-treated sulfur and powdered sulfur.

[0159] (Sulfur content)

[0160] From the viewpoint of achieving more excellent effects of the present invention, the sulfur content (net sulfur content) is preferably 0.65 parts by mass or more, and more preferably 0.70 to 3.0 parts by mass, based on 100 parts by mass of the rubber component.

[0161] (additive)

[0162] The rubber composition of the present invention may further contain additives as necessary within a range not impairing the effects of the present invention.

[0163] Examples of the additives include softeners such as paraffin oil and naphthenic oil; talc, silica; vulcanization accelerating aids (such as stearic acid), zinc oxide, vulcanization retarders, vulcanization accelerators, and antioxidants.

[0164] As a preferred embodiment of the rubber composition of the present invention, it is mentioned that the rubber composition does not contain ethylene-propylene copolymer (binary copolymer of ethylene and propylene). It should be noted that ethylene-propylene copolymer does not belong to EPDM.

[0165] One preferred embodiment of the rubber composition of the present invention is that the rubber composition does not contain a peroxide.

[0166] (Method for producing rubber composition)

[0167] The method for producing the rubber composition of the present invention is not particularly limited, and can be produced, for example, by mixing the above-mentioned essential components and optional components that can be used as needed at 100°C to 180°C.

[0168] (Vulcanization of rubber composition)

[0169] The method for vulcanizing (sulfur vulcanization) the rubber composition of the present invention is not particularly limited. The rubber composition of the present invention can be vulcanized, for example, at 140 to 190° C. As a vulcanization method, specifically, for example, pressurized vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization) or hot water vulcanization can be cited. By vulcanizing the rubber composition of the present invention, a cured product (vulcanized rubber) can be obtained.

[0170] (use)

[0171] The rubber composition of the present invention can be applied to, for example, a hose.

[0172] Examples of the hose include air conditioning hoses, and more specifically, examples include automobile air conditioning hoses.

[0173] The rubber composition of the present invention is preferably applied to the outermost layer of a hose.

[0174] [hose]

[0175] The hose of the present invention is a hose formed using the rubber composition for a hose of the present invention.

[0176] The hose of the present invention is formed using the rubber composition of the present invention, and there is no particular limitation. The rubber composition used in the hose of the present invention is not particularly limited as long as it is the rubber composition of the present invention. There is no particular limitation on which part of the hose of the present invention is formed by the rubber composition of the present invention.

[0177] (Outermost layer)

[0178] The hose of the present invention preferably has an outermost layer formed from the rubber composition of the present invention.

[0179] The thickness of the outermost layer can be set to 0.2 to 4 mm, for example.

[0180] The hose of the present invention may further include at least one selected from the group consisting of a reinforcing member (reinforcing layer), an innermost layer, and an intermediate rubber layer in addition to the outermost layer. The outermost layer may be one or more layers. The same applies to the innermost layer, the reinforcing member, and the intermediate rubber layer.

[0181] The hose of the present invention may have, for example, an innermost layer, a reinforcing member, and an outermost layer in this order.

[0182] (Innermost layer)

[0183] The innermost layer that the hose of the present invention may have is not particularly limited, and examples thereof include conventionally known innermost layers.

[0184] The thickness of the innermost layer can be set to 0.2 to 4 mm, for example.

[0185] (Reinforcement parts)

[0186] The reinforcing member that the hose of the present invention may have is not particularly limited, and examples thereof include conventionally known reinforcing members.

[0187] Examples of the material of the reinforcing member include metals and fiber materials (eg, polyamide, polyester, etc.). The reinforcing member may be a surface-treated reinforcing member.

[0188] As a form of the reinforcing member, for example, a reinforcing member woven into a spiral structure and / or a blade structure can be cited.

[0189] Examples of the hose of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the accompanying drawings.

[0190] Figure 1 This is a schematic perspective view showing an example of the hose of the present invention by cutting through each layer.

[0191] exist Figure 1 In the embodiment, the hose 1 comprises an innermost layer 2, a reinforcing member 3 on the innermost layer 2, and an outermost layer 4 on the reinforcing member 3. As one preferred embodiment, the outermost layer 4 is formed of the rubber composition of the present invention.

[0192] The method for manufacturing the hose of the present invention is not particularly limited. For example, a rubber composition for forming the innermost layer, a rubber composition for forming the reinforcing member and the outermost layer (such as the rubber composition of the present invention) may be sequentially stacked on a mandrel to form a laminate, the laminate may be covered with a nylon cloth or the like, and the laminate covered with the nylon cloth or the like may be subjected to press vulcanization, steam vulcanization, oven vulcanization (hot air vulcanization) or hot water vulcanization at 140° C. to 190° C. for 30 to 180 minutes, thereby vulcanization bonding to manufacture the hose of the present invention.

[0193] As an application of the hose of the present invention, for example, an air conditioner hose can be mentioned. More specifically, for example, an automobile air conditioner hose can be mentioned.

[0194] Example

[0195] Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

[0196] <Manufacturing of Rubber Composition>

[0197] The components in the following tables were used in the compositions (parts by mass) shown in the tables and mixed with a stirrer to produce rubber compositions.

[0198] Specifically, first, the components shown in the following tables except the vulcanization accelerator and the oil-treated sulfur were mixed in a Banbury mixer (3.4 liters) for 5 minutes and discharged when the temperature reached 160° C. to obtain a masterbatch.

[0199] Next, a vulcanization accelerator and oil-treated sulfur were added to each of the masterbatches obtained in the above manner, and these were mixed in an open roll mill to obtain a rubber composition.

[0200] In Table 1, EPDM and SBR were used as rubber components.

[0201] In Table 2, EPDM is used as the rubber component.

[0202] (Production of vulcanized sheets)

[0203] Each of the rubber compositions obtained in the above manner was vulcanized for 45 minutes at a surface pressure of 3.0 MPa using a press molding machine at 153° C. to prepare a vulcanized sheet having a thickness of 2 mm.

[0204] <<Evaluation>>

[0205] <Elongation at break>

[0206] First, a JIS No. 3 dumbbell-shaped test piece conforming to JIS K6251 was punched out from each of the vulcanized sheets to obtain an initial test piece.

[0207] Next, using each of the initial test pieces, a tensile test was performed at 23°C ± 2°C and a tensile speed of 500 mm / min in accordance with JIS K6251:2010 to measure the elongation at break (EB) [%].

[0208] In Table 1, the results of elongation at break are indicated by indices with the result of Comparative Example 1 containing Comparative EPDM 1 as EPDM being 100. In Table 2, the results of elongation at break are indicated by indices with the result of Comparative Example 6 containing Comparative EPDM 1 as EPDM being 100.

[0209] The evaluation criteria of the elongation at break are as follows.

[0210] If the elongation at break (index) is 107 or more, the obtained cured product is evaluated to have excellent elongation at break. The larger the hardness (index) is greater than 107, the more excellent the elongation at break of the obtained cured product is.

[0211] On the other hand, if the elongation at break (index) is less than 107, it is evaluated that the elongation at break of the obtained cured product is poor.

[0212] <Hardness>

[0213] First, three vulcanized sheets obtained in the above-mentioned manner (production of vulcanized sheets) were stacked together to obtain initial test sheets.

[0214] Next, a hardness measurement test was performed at 23° C. using a type A durometer in accordance with JIS K6253-3:2012 to measure the hardness of each initial test piece obtained in the above manner.

[0215] In Table 1, the results of hardness are indicated as indices with the result of Comparative Example 1 being 100, and in Table 2, the results of hardness are indicated as indices with the result of Comparative Example 6 being 100.

[0216] The evaluation criteria of hardness are as follows.

[0217] When the hardness (index) is 100 or more, the hardness of the obtained cured product is evaluated to be excellent. The greater the hardness (index) is than 100, the more excellent the hardness of the obtained cured product is.

[0218] On the other hand, when the hardness (index) is less than 100, it is evaluated that the hardness of the obtained cured product is poor.

[0219] <Ozone resistance>

[0220] First, each test piece obtained in the above-mentioned (production of vulcanized piece) was cut into a JIS No. 3 dumbbell-shaped test piece conforming to JIS K6251.

[0221] Next, each test piece was stretched by 30%, and subjected to ozone degradation under the conditions of an ozone concentration of 100 pphm and 50° C. for 72 hours. The presence or absence of ozone cracking on the surface of the test piece was visually evaluated.

[0222] The obtained results are shown in the "ozone resistance" column of each table.

[0223] The evaluation criteria for ozone resistance are as follows.

[0224] If there was no ozone cracking on the surface of the test piece, it was evaluated as having excellent ozone resistance and indicated as "no cracking".

[0225] On the other hand, if ozone cracks were present on the surface of the test piece, the ozone resistance was evaluated as poor and indicated as "cracks were present".

[0226] [Table 1]

[0227]

[0228] [Table 2]

[0229]

[0230] The details of each component shown in each table are as follows.

[0231] (Rubber component)

[0232] Comparative EPDM1 Keltan 6950C (China): an ethylene-propylene-non-conjugated diene copolymer having a diene content of 8% by mass and an EE content of 28.9 mol%, manufactured by LANXESS.

[0233] Comparative EPDM2 Keltan 6950C (Netherlands): an ethylene-propylene-non-conjugated diene copolymer having a diene content of 9 mass % and an EE content of 30.2 mol %. Produced by LANXESS.

[0234] Comparative EPDM3 EPT9090M: an ethylene-propylene-non-conjugated diene copolymer having a diene content of 11% by mass and an EE content of 32.8 mol%, manufactured by Mitsui Chemicals.

[0235] (ethylene-propylene-non-conjugated diene copolymer)

[0236] EPDM1 KEP370F: Ethylene-propylene-non-conjugated diene copolymer with a diene content of 9 mass % and an EE content of 39.7 mol %. EE content / EP content is 0.73. The weight average molecular weight is 150,000 and the molecular weight distribution is 7.7. The non-conjugated diene is 5-ethylidene-2-norbornene. Produced by KUMHO

[0237] EPDM24110M: Ethylene-propylene-non-conjugated diene copolymer with a diene content of 7% by mass and an EE content of 49.7 mol%. EE content / EP content is 1.21. The weight average molecular weight is 449,000 and the molecular weight distribution is 2.3. The non-conjugated diene is 5-ethylidene-2-norbornene. Produced by SSME

[0238] ·SBR: Styrene butadiene rubber. Trade name NIPOL 1502, produced by Japan ZEON (carbon black)

[0239] ·FEF carbon black: trade name Niteron#10N, produced by New Sun Chemical Carbon Black Co., Ltd. Iodine adsorption 41±4mg / g, N2SA: 42±4m 2 / g, DBP oil absorption 121±6ml / 100g.

[0240] SRF carbon black: trade name Asahi 50, produced by Asahi Carbon Co., Ltd. Iodine adsorption 20±5mg / g, N2SA: 25±5m 2 / g, DBP oil absorption 55~79ml / 100g.

[0241] Talc: Trade name: MISTRON VAPOR, produced by Imerys

[0242] · Naphthenic oil: Trade name Comolex H22, produced by JXTG Energy Corporation

[0243] Paraffin oil: Trade name SUNPAR 2280. Produced by Japan Sun Oil Company.

[0244] PVI: vulcanization retarder. N-cyclohexylthiophthalimide. Trade name Retarder CTP, produced by Toray Fine Chemicals Co., Ltd.

[0245] Zinc oxide: Zinc oxide JIS#3, manufactured by Zhengtong Chemical Industry Co., Ltd.

[0246] Stearic acid: Stearic acid 50S, produced by Chiba Fatty Acid Co.

[0247] ·Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazole sulfenamide. Sulfenamides. Ouchi Shinshin Chemical Industry Co., Ltd. produces Nocceler CZ-G

[0248] ·Vulcanization accelerator TET: Tetraethylthiuram disulfide. Thiuram type. Ouchi Shinko Chemical Industry Co., Ltd. produces Nocceler TET-G

[0249] ·Vulcanization accelerator TRA: Dipentamethylenethiuram tetrasulfide. Thiuram type. Nocceler TRA produced by Ouchi Shinko Chemical Industry Co., Ltd.

[0250] Vulcanization accelerator TT: Tetramethylthiuram disulfide. Thiuram type. Nocceler TT manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0251] Vulcanization accelerator DM: dibenzothiazole disulfide. Thiazoles. Sanceler DM, produced by Sanxin Chemical Industry Co., Ltd. (sulfur)

[0252] Oil-treated sulfur: produced by Hosoi Chemical Industry Co., Ltd. The oil-treated sulfur contains sulfur. The concentration of sulfur in the oil-treated sulfur is 95% by mass.

[0253] As can be seen from the results shown in Table 1, the elongation at break of Comparative Examples 1 to 3 containing EPDM with an EE content of less than 35.0 mol % was poor.

[0254] Comparative Example 4, in which the EPDM content with an EE amount of less than 35.0 mol % was 30 mass % in the rubber component, was inferior in elongation at break, hardness and ozone resistance.

[0255] Comparative Example 5, in which the content of the specific EPDM was less than 40% by mass in the rubber component, had poor ozone resistance.

[0256] As can be seen from the results shown in Table 2, Comparative Examples 6 to 8 containing EPDM with an EE content of less than 35.0 mol % were inferior in elongation at break or hardness.

[0257] In contrast, the rubber composition of the present invention is excellent in elongation at break, hardness, and ozone resistance.

[0258] Description of Reference Numerals

[0259] 1: Hose

[0260] 2: Innermost layer

[0261] 3: Enhanced components

[0262] 4: Outermost layer

Claims

1. A rubber composition comprising: A rubber component containing 40% by mass or more of an ethylene-propylene-non-conjugated diene copolymer, wherein the amount of diene in the copolymer is 6% by mass or more and the content of the ethylene-ethylene chain structure is 35.0 mol% or more; Carbon black; and sulfur.

2. The rubber composition according to claim 1, wherein The molar ratio of the ethylene-ethylene chain structure to the ethylene-propylene chain structure in the ethylene-propylene-non-conjugated diene copolymer is 1.0 or more.

3. The rubber composition according to claim 1 or 2, wherein: The entire amount of the rubber component is the ethylene-propylene-non-conjugated diene copolymer.

4. The rubber composition according to any one of claims 1 to 3, wherein The content of the carbon black is 70 parts by mass or more relative to 100 parts by mass of the rubber component. The sulfur content is 0.65 parts by mass or more relative to 100 parts by mass of the rubber component. 5 . The rubber composition according to claim 1 , which is used for a hose. 6 . A hose formed using the rubber composition according to claim 1 .

7. The hose according to claim 6, which is used for an air conditioner.

8. The hose according to claim 6 or 7, which has an outermost layer formed using the rubber composition.

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