TW202134332A - Rubber composition for hose, and hose - Google Patents

Abstract

The present invention addresses the problem of providing a rubber composition for a hose capable of producing a hose having both excellent flame retardancy and wear resistance, and a hose produced using the same. A rubber composition for a hose containing a rubber component, which includes a chloroprene rubber and a butadiene rubber, and silica, wherein the content of the chloroprene rubber is 60-75 mass% relative to the total mass of the rubber component, the content of the butadiene rubber is 25-40 mass% relative to the total mass of the rubber component, the content of styrene-butadiene rubber optionally included in the rubber component is 0 mass% to less than 10 mass% relative to the total mass of the rubber component, and the content of the silica is 5-25 mass parts relative to 100 mass parts of the rubber component.

Description

Rubber composition for hose and hose

The present invention relates to a rubber composition for a hose and a hose.

Hoses used in hydraulic systems for construction machinery and work machines (Hydraulic piping hoses have increased in use in coal mines and mines in recent years, so flame retardancy is required in consideration of safety during operation. Here, regarding the flame retardancy required for hydraulic piping hoses, for example, in the United States, it is mainly regulated by MSHA (Mine Safety and Health Administration; Mining Safety and Health Administration) standards (American Mine Safety Standards).

As a rubber composition for hoses with improved flame retardancy, Patent Document 1 describes "a rubber composition for hoses characterized by containing chloroprene rubber, butadiene rubber, and styrene-butadiene rubber. As the rubber component, olefin rubber contains 60 parts by mass to 80 parts by mass of chloroprene rubber, 10 parts by mass to 30 parts by mass of butadiene rubber, and 10 parts by mass to 30 parts by mass in 100 parts by mass of the aforementioned rubber component. Parts of styrene-butadiene rubber is prepared by blending 5 parts by mass to 25 parts by mass of silicon dioxide relative to 100 parts by mass of the aforementioned rubber component" ([Request 1], [0005]). [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent No. 5813480

[The problem to be solved by the invention]

The inventors of the present invention have studied the hose described in Patent Document 1 and have shown that although the flame retardancy is good, there is still room for improvement in the wear resistance.

Therefore, the subject of the present invention is to provide a rubber composition for a hose capable of producing a hose having excellent flame resistance and abrasion resistance, and a hose produced using the rubber composition for a hose. [Technical means to solve the problem]

The inventors of the present invention conducted intensive research to achieve the above-mentioned problems and found that by using the following rubber composition, the resulting hose has good flame retardancy and abrasion resistance, thereby completing the present invention, the rubber composition Contains the rubber component with the content of chloroprene rubber, butadiene rubber and optional styrene butadiene rubber set to a specific ratio and a specific amount of silicon dioxide. That is, the inventors of the present invention found that the above-mentioned problem can be solved by the following configuration.

[1] A rubber composition for hoses, comprising: rubber components including chloroprene rubber and butadiene rubber, and silicon dioxide; Relative to the total mass of the above-mentioned rubber components, the content of the above-mentioned chloroprene rubber is 60% to 75% by mass; Relative to the total mass of the above-mentioned rubber components, the content of the above-mentioned butadiene rubber is 25% to 40% by mass; The content of any styrene butadiene rubber contained in the rubber component is 0% by mass or more and less than 10% by mass relative to the total mass of the rubber component; The content of the silicon dioxide is 5 to 25 parts by mass relative to 100 parts by mass of the rubber component.

[2] The rubber composition for a hose as described in [1], wherein the total content of the chloroprene rubber and the butadiene rubber exceeds 90% by mass relative to the total mass of the rubber components. [3] The rubber composition for a hose as described in [1] or [2], wherein the rubber component is composed only of the chloroprene rubber and the butadiene rubber. [4] The rubber composition for a hose as described in any one of [1] to [3] above, which further contains a silane coupling agent.

此處，上述式(1)中， R¹ 至R⁶ 分別獨立地表示碳數1至5之烷基。 m及n分別獨立地表示1至3之整數。 x表示2至8之整數。[5] The rubber composition for a hose as described in [4], wherein the silane coupling agent is a compound represented by the following formula (1).

Here, in the above formula (1), R ¹ to R ⁶ each independently represent an alkyl group having 1 to 5 carbon atoms. m and n each independently represent an integer of 1 to 3. x represents an integer from 2 to 8.

[6] The rubber composition for a hose as described in [4] or [5], wherein the content of the silane coupling agent is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component. [7] The rubber composition for a hose as described in any one of [1] to [6], which further contains carbon black; The content of the carbon black is 40 to 90 parts by mass relative to 100 parts by mass of the rubber component. [8] A hose having a rubber layer formed of the rubber composition for a hose as described in any one of [1] to [7]. [9] The hose according to [8], wherein the rubber layer is provided on the outermost layer. [Effects of Invention]

As shown below, according to the present invention, it is possible to provide a rubber composition for a hose capable of producing a hose having excellent flame retardancy and abrasion resistance, and a hose produced using the rubber composition for a hose.

The present invention will be described in detail below. The description of the constituent elements described below may be based on the representative embodiment of the present invention, but the present invention is not limited to such an embodiment. Furthermore, in this specification, the numerical range indicated by "to" refers to a range that includes the numerical values described before and after "to" as the lower limit and the upper limit. In addition, in this specification, for each component system, the substance corresponding to each component may be used individually by 1 type, and may use 2 or more types together. Here, when two or more substances are used in combination for each component, the content related to the component refers to the total content of the combined substances unless otherwise specified.

[Rubber composition for hose] The rubber composition for hoses of the present invention (hereinafter also referred to as "rubber composition of the present invention") is a rubber composition for hoses containing a rubber component including chloroprene rubber and butadiene rubber, and silicon dioxide Things. In addition, in the rubber composition of the present invention, the content of the chloroprene rubber is 60% to 75% by mass relative to the total mass of the rubber components, and relative to the total mass of the rubber components, the butadiene rubber The content of styrene butadiene rubber is 25% to 40% by mass, relative to the total mass of the rubber component, the content of any styrene butadiene rubber contained in the rubber component is 0% by mass or more and less than 10% by mass. Furthermore, in the rubber composition of the present invention, the content of the silicon dioxide is 5 to 25 parts by mass relative to 100 parts by mass of the rubber component.

In the present invention, as described above, the flame retardancy and abrasion resistance of the obtained hose are good by using the following rubber composition. The rubber composition contains chloroprene rubber, butadiene The content of rubber and optional styrene butadiene rubber is set to a specific ratio of rubber components and a specific amount of silicon dioxide. Although the details of this point have not yet been clarified, the inventors of the present invention make the following guess. That is, it can be considered that the rubber component contained in the rubber composition of the present invention contains chloroprene rubber and butadiene rubber in the above-mentioned mass ratio, so that it can take into account the self-restraint during combustion without compromising the kneading properties. The combustible gas dilution effect of hydrogen chloride gas produced by chloroprene rubber and the abrasion resistance of butadiene rubber, so the flame retardancy and abrasion resistance of the resulting hose are improved. In addition, it can be considered that any styrene butadiene rubber that can be contained in the rubber component is in the above-mentioned mass ratio, thereby maintaining the flame retardancy improvement effect obtained from the chloroprene rubber, and maintaining the quality obtained from the butadiene rubber Abrasion resistance improvement effect. Furthermore, the rubber composition of the present invention contains silicon dioxide in the above-mentioned parts by mass, whereby the fire fighting effect (especially afterglow) obtained from the hydrate contained in silicon dioxide can be fully exerted, while maintaining the required wear resistance. Consuming. Hereinafter, each component contained in the rubber composition of the present invention will be described in detail.

[Rubber component] The rubber component contained in the rubber composition of the present invention is as described above. The content of chloroprene rubber is 60% to 75% by mass relative to the total mass of the rubber component. Relative to the total mass of the rubber component, butadiene The content of the olefin rubber is 25% by mass to 40% by mass, and the content of any styrene butadiene rubber contained in the rubber component is 0% by mass or more and less than 10% by mass relative to the total mass of the above-mentioned rubber components.

＜Chloroprene rubber＞ The chloroprene rubber (CR) contained in the rubber component is not particularly limited, and conventionally known ones can be used.

In the present invention, the content of the chloroprene rubber is 60% to 75% by mass relative to the total mass of the rubber components. For the reason that the flame retardancy of the resulting hose becomes better, it is preferably 65% to 75% by mass.

＜Butadiene rubber＞ The butadiene rubber (BR) contained in the rubber component is not particularly limited, and conventionally known ones can be used. The weight average molecular weight of the butadiene rubber is not particularly limited, and is preferably 50,000 to 1,000,000, more preferably 200,000 to 800,000.

In the present invention, as the above-mentioned butadiene rubber, a butadiene rubber having a high cis structure is preferable, specifically, butadiene having a cis-1,4 bond content of 90% or more is preferable The rubber is more preferably a butadiene rubber with a cis-1,4 bond content of 95% or more. Furthermore, the butadiene rubber with the high cis structure can be polymerized by the usual methods such as the use of Ziegler-based catalysts or neodymium catalysts.

In the present invention, the content of butadiene rubber is 25% to 40% by mass relative to the total mass of the rubber components. For the reason that the abrasion resistance of the resulting hose becomes better, it is preferably 30% to 40% by mass.

＜Any rubber＞ If the rubber component contains the above-mentioned chloroprene rubber and butadiene rubber in the above-mentioned mass %, it may further contain other arbitrary rubbers. As other optional rubbers, specific examples include: natural rubber (NR), isoprene rubber (IR), styrene butadiene rubber (SBR), acrylonitrile butadiene rubber (NBR), butadiene rubber Base rubber (IIR), halogenated butyl rubber (Br-IIR, Cl-IIR), ethylene propylene diene rubber (EPDM), etc., these may be used alone or in combination of two or more. However, in the present invention, when the other arbitrary rubber is styrene butadiene rubber, the content of the arbitrary styrene butadiene rubber is 0% by mass or more and less than the total mass of the above-mentioned rubber components. 10% by mass. In addition, in the present invention, it is preferable that acrylonitrile butadiene rubber is not contained as any other rubber.

In the present invention, for the reason that the flame retardancy and abrasion resistance of the hose obtained are improved, the chloroprene rubber and the butadiene rubber are relative to the total mass of the rubber components. The total content is preferably more than 90% by mass.

In addition, in the present invention, for the reason that the flame retardancy and abrasion resistance of the obtained hose become better, the rubber component is preferably composed solely of the chloroprene rubber and the butadiene Made of rubber.

[Silica Dioxide] The silicon dioxide contained in the rubber composition of the present invention is not particularly limited, and conventionally known ones can be used. Examples of silicon dioxide include natural silicon dioxide, fused silicon dioxide, amorphous silicon dioxide, hollow silicon dioxide, and vapor phase silicon dioxide. In addition, there are no particular restrictions on the production of silicon dioxide, and examples thereof include a wet method and a dry method.

In the present invention, the content of silicon dioxide is 5 parts by mass to 25 parts by mass, preferably 5 parts by mass to 15 parts by mass relative to 100 parts by mass of the above-mentioned rubber component.

[Silane Coupling Agent] The rubber composition of the present invention preferably contains a silane coupling agent for the reason that the abrasion resistance of the resulting hose becomes better.

In the present invention, the above-mentioned silane coupling agent is preferably a compound represented by the following formula (1) for the reason that the abrasion resistance of the obtained hose becomes better.

In the above formula (1), R ¹ to R ⁶ each independently represent an alkyl group having 1 to 5 carbon atoms. Specific examples of the alkyl group having 1 to 5 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group. Among them, a methyl group or an ethyl group is preferred. In addition, in the above formula (1), m and n each independently represent an integer of 1 to 3, and 2 or 3 are preferred. In the above formula (1), x represents an integer from 2 to 8, preferably an integer from 2 to 4.

As the silane coupling agent represented by the above formula (1), for example, bis-[3-(triethoxysilyl)-propyl]tetrasulfide, bis[3-(triethoxysilyl) -Propyl]disulfide, 3-trimethoxysilylpropyl-N,N-dimethylsulfanylaminomethanyl-tetrasulfide, trimethoxysilylpropyl-mercaptobenzothiazole tetrasulfide , Triethoxysilylpropyl-methacrylate-monosulfide, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane and dimethoxymethylsilane Propyl-N,N-dimethylsulfanylaminomethanyl-tetrasulfide and the like.

Among these, from the viewpoint of the effect of improving the reinforcement of the hose, bis(3-triethoxysilylpropyl)tetrasulfide or bis-(3-triethoxysilylpropyl) is preferred. Disulfide. In addition, as these commercially available products, for example, Si69 [bis-(3-triethoxysilylpropyl) tetrasulfide; manufactured by Evonic Degussa], and Si75 [double -(3-Triethoxysilylpropyl) disulfide; manufactured by Evonic Degussa] and the like.

In the present invention, for the reason that the abrasion resistance of the resulting hose becomes better, the content of the silane coupling agent is preferably 0.5 parts by mass or more, more preferably 0.5 parts by mass relative to 100 parts by mass of the above-mentioned rubber component. Parts by mass to 6 parts by mass.

[Carbon Black] The rubber composition of the present invention preferably contains carbon black for the reason of improving the reinforcement of the resulting hose. The above carbon black is not particularly limited. For example, various grades such as SAF-HS, SAF, ISAF-HS, ISAF, ISAF-LS, IISAF-HS, HAF-HS, HAF, HAF-LS, FEF, GPF, SRF, etc. can be used. Things. One kind of carbon black may be used alone, or two or more kinds may be used in combination. Regarding the content in the case of containing carbon black, it is preferably 40 to 90 parts by mass relative to 100 parts by mass of the above-mentioned rubber component, and it is more preferable for the reason that it can have excellent wear resistance and workability. 60 parts by mass to 80 parts by mass.

[additive] The rubber composition of the present invention may further contain additives as needed. Examples of additives include fillers, plasticizers, softeners, anti-aging agents, organic activators, antioxidants, antistatic agents, flame retardants, vulcanization accelerators, other than the aforementioned silica and carbon black, Crosslinking accelerators, vulcanization retarders, ozone degrading agents, processing oils (aromatherapy oils), adhesives, waxes, fatty acid esters, vulcanizing agents (for example, sulfur), etc.

Examples of fillers include clay, talc, iron oxide, zinc oxide (ZnO), titanium oxide, barium oxide, magnesium oxide, calcium carbonate, magnesium carbonate, zinc carbonate, barium sulfate, mica, and diatomaceous earth. Wait. These may be used individually by 1 type, and may use 2 or more types together.

As the plasticizer, for example, dioctyl phthalate (DOP), dibutyl phthalate (DBP), dioctyl adipate (DOA), isodecyl succinate, and diethylene two Alcohol dibenzoate, pentaerythritol ester, butyl oleate, methyl acetyl ricinoleate, tricresyl phosphate, trioctyl phosphate, trimellitate, propylene glycol polyester adipate, adipic acid Butylene glycol polyester and naphthenic oil, etc. These may be used individually by 1 type, and may use 2 or more types together.

Specific examples of the softener include aromatherapy oils, naphthenic oils, paraffin oils, petroleum resins, vegetable oils, and liquid rubber. These may be used individually by 1 type, and may use 2 or more types together.

Examples of anti-aging agents include: N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), N,N'-dinaphthyl-p-phenylenediamine (DNPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), styrenated phenol (SP) and 2,2,4-trimethyl-1,2-dihydroquinoline Polymer (RD) and so on. These may be used individually by 1 type, and may use 2 or more types together.

As an organic type activating agent, stearic acid, oleic acid, lauric acid, zinc stearate, etc. are mentioned, for example. These may be used individually by 1 type, and may use 2 or more types together.

Examples of antioxidants include butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA).

Examples of the antistatic agent include quaternary ammonium salts; hydrophilic compounds such as polyglycol and ethylene oxide derivatives.

Examples of flame retardants include chloroalkyl phosphate, dimethyl methylphosphonate, bromine-phosphorus compounds, ammonium polyphosphate, bromoneopentane-polyether, and brominated polyether. In addition, examples of non-halogen-based flame retardants include aluminum hydroxide, magnesium hydroxide, tricresyl phosphate, diphenyl cresyl phosphate, and the like.

As the crosslinking accelerator, the usual rubber additives can be used together. As the rubber auxiliary agent, for example, zinc bloom; stearic acid, oleic acid, zinc salts of these, etc. can be used.

Examples of the adjuvant may include triazine thiol-based compounds (for example, 2,4,6-trimercapto-1,3,5-triazine, 6-butylamino-2,4-dimercapto-1 ,3,5-triazine), resorcinol, cresol, resorcinol-formalin latex, monomethylol melamine, monomethylol urea, ethylene maleimide, naphthenic acid Cobalt, cobalt stearate, cobalt neodecanoate and cobalt dodecanoate, etc. These may be used individually by 1 type, and may use 2 or more types together.

[Method of manufacturing rubber composition for hose] The method for producing the rubber composition for hoses of the present invention is not particularly limited. Specific examples include: using a known method and device (such as a Banbury mixer, kneader, roller, etc.) to combine the above-mentioned components The method of mixing and so on. In addition, when the rubber composition for a hose of the present invention contains a vulcanizing agent or a vulcanization accelerator, the following method can be cited: using a Banbury mixer or the like to combine the above-mentioned essential components and additives that can be used as needed (vulcanization) After kneading to prepare a mixture, a vulcanizing agent and a vulcanization accelerator are added to the above-mentioned mixture, and these are kneaded using a kneading roller or the like to prepare a rubber composition. In addition, the rubber composition for a hose of the present invention can be vulcanized or cross-linked under conventionally known vulcanization or cross-linking conditions.

[hose] The hose of the present invention is a hose having a rubber layer formed from the rubber composition for a hose of the present invention. The hose of the present invention has a rubber layer formed using the rubber composition for a hose of the present invention, and therefore has good flame retardancy and abrasion resistance. Therefore, as one of the preferred methods, the hose of the present invention is a flame-retardant hose.

[Rubber layer] Examples of the rubber layer included in the hose of the present invention include a rubber cover layer, an inner rubber layer, and an intermediate rubber layer. ＜Rubber cover＞ As one of the preferred modes, the hose of the present invention has a rubber cover layer constituting the outermost layer, and the rubber cover layer (outermost layer) is formed using the rubber composition of the present invention. The thickness of the rubber cover can be set from 0.2 mm to 4 mm.

＜Inner rubber layer＞ The rubber composition forming the inner rubber layer is not particularly limited. For example, those well known in the past can be cited. The composition of the present invention can also be used to form the inner rubber layer. The thickness of the inner rubber layer can be set to 0.2 mm to 4 mm, for example.

＜Middle rubber layer＞ The rubber composition forming the intermediate rubber layer is not particularly limited. For example, those well known in the past can be cited. The composition of the present invention can also be used to form an intermediate rubber layer. The hose of the present invention may have one or more intermediate rubber layers. The thickness of the middle rubber layer can be set to 0.2 mm to 0.7 mm, for example.

＜Reinforcement layer＞ When there are multiple rubber layers, the hose of the present invention may further have a reinforcing layer between the rubber layers. The reinforcing layer can also be one or more layers. The material of the reinforcing layer is not particularly limited. For example, metals and fiber materials (polyamide, polyester, etc.) can be cited. In addition, examples of the form of the reinforcing layer include blades and spirals.

Hereinafter, the hose of the present invention will be described with reference to the drawings. The present invention is not limited to the drawings. Fig. 1 is a perspective view showing an example of the hose of the present invention by cutting through each layer. In Fig. 1, the hose 1 has an inner rubber layer 2 as an inner layer, and a reinforcing layer 3 and a rubber cover layer 4 as an outer layer on the upper layer.

Fig. 2 is a perspective view showing another example of the hose of the present invention by cutting each layer. In FIG. 2, the hose 5 has an inner rubber layer 10 in the innermost layer, and a rubber cover layer 23 as the outermost layer. Between the inner rubber layer 10 and the rubber cover layer 23, there are alternately intermediate rubber layers 11, 13, 15, and 17, 19, 21 and reinforcement layers 12, 14, 16, 18, 20, 22.

[Manufacturing method of hose] There are no particular restrictions on the method of manufacturing the hose of the present invention. For example, the following method can be mentioned: after laminating the inner rubber layer, the middle rubber layer, the reinforcing layer and the rubber cover layer in sequence on the mandrel, and then covering the laminate with nylon cloth, etc., the conditions are at 140°C to 190°C Next, steam vulcanization, oven vulcanization (hot gas vulcanization) or warm water vulcanization are carried out, and then vulcanization is carried out to manufacture the hose of the present invention.

[Use of hose] The hose of the present invention can be used, for example, as a hydraulic hose, a hose for conveying refrigerant, a marine hose, and the like. [Example]

Hereinafter, examples are given to illustrate the present invention in more detail. The materials, usage amount, ratio, processing content, processing sequence, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the examples shown below.

[Comparative Example 1 to Comparative Example 5 and Example 1 to Example 17] [Preparation of rubber composition] Using a Banbury mixer, the components shown in the following tables 1 to 4 except for the four components (sulfur, zinc oxide, vulcanization accelerator TS and vulcanization accelerator DG) are in the proportions shown in the table (Parts by mass) kneaded to prepare a masterbatch. Then, the above-mentioned four components are added to the obtained master batch, and they are kneaded with an open roll to prepare a rubber composition.

[Evaluate] The following evaluations were performed using the prepared rubber composition. The results are shown in Tables 1 to 4 below.

＜Munnar Viscosity＞ For each rubber composition obtained, according to JIS K6300-1:2013 (Unvulcanized Rubber-Physical Properties-Part 1: Method of Obtaining Viscosity and Scorch Time (Scorch Time) Using Menner Viscometer) described in "Meng Nanoviscosity test” uses a Munner viscometer (L-shaped rotor) to measure the Munner viscosity under the conditions of a preheating time of 1 minute and a test temperature of 125°C. When the Monner viscosity is less than 100, it can be evaluated as excellent in processability.

＜Abrasion resistance (DIN abrasion test)＞ For each rubber composition obtained, a press molding machine was used to vulcanize at 148°C and a surface pressure of 3.0 MPa for 45 minutes to produce a sheet, and then punch into a disc with a diameter of 16.0 mm±0.2 mm and a thickness of 6 mm.状测试片。 Shape test piece. Using the above-mentioned test piece, the abrasion resistance was evaluated in accordance with JIS K6264-2 (DIN abrasion test B method). When the abrasion amount of Comparative Example 1 is 100 (index), when the abrasion amount becomes 70 or less (index), it can be evaluated that the abrasion resistance is excellent.

＜Flame retardant＞ For each rubber composition obtained, press and vulcanize using a model at 148°C and a surface pressure of 3.0 MPa for 45 minutes, and cut out the obtained vulcanized rubber sheet into a length of 150 mm, a width of 12.7 mm, and a thickness of 2.5 mm. , Obtain flame-retardant evaluation samples. Based on the flame-retardant evaluation of MSHA standard (American mine safety standard) ASTP5007 (version (version): 2012-02-12), the flame-retardant evaluation sample obtained as described above was used to determine the flame disappearance time and embers disappearance time. The flame disappearance time and ember disappearance time obtained are applied to the following standards to evaluate the flame retardancy. (Assessment criteria) In the case where the flame disappearance time is 60 seconds or less or/and the embers disappearance time is 180 seconds or less, it is evaluated that the flame retardancy is excellent, and this is indicated as "〇". In the case where the flame disappearance time exceeds 60 seconds or/and the ember disappearance time exceeds 180 seconds, it is evaluated as poor flame retardancy, which is expressed as "×".

The details of each component shown in Table 1 to Table 4 above are as follows. • Styrene butadiene rubber: Nipol 1502 (manufactured by Zeon, Japan) • Butadiene rubber: Nipol BR1220 (manufactured by Zeon, Japan) • Chloroprene rubber: Denka chloroprene S-41 (manufactured by Denka)

Carbon black: Niteron#10N (FEF grade carbon black, manufactured by Nippon Chemical Carbon Co., Ltd.) Silicon dioxide: Nipsil AQ (manufactured by Tosoh Silica) Silane coupling agent: Si69 [bis-(3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonic Degussa] Oil: A/O MIX 2010 (manufactured by Sankyo Oil Chemical Industry Co., Ltd.) Magnesium oxide: Kyowamag 150 (manufactured by Kyowa Chemical Industry Co., Ltd.) Stearic acid: N stearic acid for industrial use (manufactured by Chiba Fatty Acid Co., Ltd.) Sulfur: Oil treatment sulfur (manufactured by Hosui Chemical Industry Co., Ltd.) Zinc oxide: three types of zinc oxide (manufactured by Zhengtong Chemical Industry Co., Ltd.) Vulcanization accelerator TS: Sanceler TS-G (manufactured by Sanshin Chemical Industry Co., Ltd.) Vulcanization accelerator D-G: Sanceler D-G (manufactured by Sanshin Chemical Industry Co., Ltd.)

From the results shown in Table 1 above, it is known that if a rubber component containing 15% by mass of SBR, no BR and 85% by mass of CR is used, the abrasion resistance is inferior (Comparative Example 1). In addition, it was found that if a rubber component containing 15% by mass of SBR, 15% by mass of BR, and 70% by mass of CR is used, the abrasion resistance is poor (Comparative Example 2). In addition, it was found that even when SBR is not included, if a rubber component containing 50% by mass of BR and 50% by mass of CR is used, the flame retardancy is poor (Comparative Example 3). In addition, it was found that if a rubber component containing 10% by mass of SBR is used as the rubber component, the abrasion resistance is inferior (Comparative Example 4). In addition, it was found that even in the case of not containing SBR, if a rubber component containing 20% by mass of BR and 80% by mass of CR is used, the abrasion resistance is inferior (Comparative Example 5).

On the other hand, from the results shown in Tables 2 to 4 above, if the content of chloroprene rubber is 60% to 75% by mass relative to the total mass of the rubber components, it can be seen from the total mass of the rubber components. The content of butadiene rubber is 25% to 40% by mass, and the content of any styrene butadiene rubber contained in the rubber component is 0% by mass or more and less than 10% relative to the total mass of the above-mentioned rubber components. With a mass% rubber component, a hose with excellent flame retardancy and abrasion resistance can be produced (Example 1 to Example 17). In addition, from the comparison between Example 6 and Example 8 to Example 11, it is known that if the silane coupling agent is blended, a hose with better abrasion resistance can be produced.

1,5: hose 2,10: inner rubber layer 3,12,14,16,18,20,22: reinforcement layer 4,23: Rubber cover 11, 13, 15, 17, 19, 21: middle rubber layer

[Fig. 1] It is a perspective view showing an example of the hose of the present invention by cutting through each layer. Fig. 2 is a perspective view showing another example of the hose of the present invention by cutting each layer.

1: hose

2: Inside rubber layer

3: Reinforcing layer

4: Rubber cover

Claims (9)

A rubber composition for hoses, containing: rubber components including chloroprene rubber and butadiene rubber, and silicon dioxide; Relative to the total mass of the rubber component, the content of the chloroprene rubber is 60% to 75% by mass; Relative to the total mass of the rubber component, the content of the butadiene rubber is 25% to 40% by mass; Relative to the total mass of the rubber component, the content of any styrene butadiene rubber contained in the rubber component is 0% by mass or more and less than 10% by mass; The content of the silicon dioxide is 5 to 25 parts by mass relative to 100 parts by mass of the rubber component. The rubber composition for a hose according to claim 1, wherein the total content of the chloroprene rubber and the butadiene rubber exceeds 90% by mass relative to the total mass of the rubber component. According to claim 1 or 2, the rubber composition for a hose, wherein the rubber component is composed only of the chloroprene rubber and the butadiene rubber. The rubber composition for a hose according to any one of claims 1 to 3, which further contains a silane coupling agent. The rubber composition for hoses of claim 4, wherein the silane coupling agent is a compound represented by the following formula (1):

Here, in the formula (1), R ¹ to R ⁶ each independently represent an alkyl group having 1 to 5 carbon atoms; m and n each independently represent an integer of 1 to 3; and x represents an integer of 2 to 8. The rubber composition for hoses of claim 4 or 5, wherein the content of the silane coupling agent is 0.5 parts by mass or more with respect to 100 parts by mass of the rubber component. Such as the rubber composition for hoses of any one of claims 1 to 6, which further contains carbon black; The content of the carbon black is 40 parts by mass to 90 parts by mass relative to 100 parts by mass of the rubber component. A hose having a rubber layer formed of the rubber composition for a hose according to any one of claims 1 to 7. Such as the hose of claim 8, wherein the rubber layer is provided on the outermost layer.

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