Rubber composition, laminate, and hose

Abstract

The purpose of the present invention is to provide: a rubber composition having excellent wear resistance and adhesion between the obtained vulcanized rubber and a reinforcing layer having a metal surface; and a laminate provided with a reinforcing layer having a metal surface and a rubber layer made of vulcanized rubber as the rubber composition. The present invention relates to a rubber composition comprising 100 parts by mass of a rubber component comprising chloroprene rubber, a rubber composition containing 5-14 parts by mass (inclusive) of silica, 1.0 part by mass or less of sulfur, and ethylene thiourea; and a laminate and a hose provided with a reinforcement layer having a metal surface and a rubber layer made of vulcanized rubber as the rubber composition.

Description

Technical Field

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

[0002] Conventionally, as a hydraulic hose used in construction machinery and the like, for example, a hose can be cited in which brass-plated wires are used in a reinforcing layer, and the brass-plated wires are directly bonded to a covering rubber layer.

[0003] The industry has proposed a metal-bonding rubber composition that can be used in hydraulic hoses and the like (for example, Patent Document 1).

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2014-214189 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] In a hose such as a hydraulic hose, when the reinforcing layer having a metal surface is directly bonded to the rubber layer as described above, excellent adhesiveness between the reinforcing layer and the rubber layer and excellent abrasion resistance of the rubber layer are required.

[0009] In this case, the inventors of the present invention prepared a rubber composition containing chloroprene rubber and sulfur with reference to Patent Document 1 and evaluated it. As a result, it was found that the vulcanized rubber obtained from this rubber composition had at least one of poor adhesiveness to the reinforcing layer having a metal surface and poor abrasion resistance.

[0010] Therefore, an object of the present invention is to provide a rubber composition in which the obtained vulcanized rubber has excellent adhesiveness and abrasion resistance to a reinforcing layer having a metal surface.

[0011] In addition, an object of the present invention is also to provide a laminate and a hose.

[0012] Means for Solving the Problems

[0013] The inventors of the present invention conducted in-depth research to solve the above problems and found that a desired effect can be obtained by using a rubber composition containing 5 parts by mass or more and 14 parts by mass or less of silica, 1.0 part by mass or less of sulfur, and ethylene thiourea with respect to 100 parts by mass of a rubber component containing chloroprene rubber, thereby completing the present invention.

[0014] The present invention was completed based on the above insights and the like. Specifically, it is an invention that solves the above problems through the following configuration.

[0015] [1] A rubber composition, the rubber composition containing: relative to 100 parts by mass of a rubber component containing chloroprene rubber,

[0016] 5 parts by mass or more and 14 parts by mass or less of silica,

[0017] 1.0 part by mass or less of sulfur, and ethylene thiourea.

[0018] [2] The rubber composition according to [1], wherein, relative to 100 parts by mass of the above rubber component, the content of the above ethylene thiourea is 0.5 to 1.0 part by mass.

[0019] [3] The rubber composition according to [1] or [2], wherein, relative to 100 parts by mass of the above rubber component, the content of the above silica is 10 parts by mass or more.

[0020] [4] The rubber composition according to any one of [1] to [3], the rubber composition further containing a polyol having a molecular weight of 300 or less,

[0021] relative to 100 parts by mass of the above rubber component, the content of the above polyol is 1 part by mass or more.

[0022] [5] The rubber composition according to any one of [1] to [4], wherein, relative to 100 parts by mass of the above rubber component, the content of the above sulfur is 0.5 to 0.8 part by mass.

[0023] [6] The rubber composition according to any one of [1] to [5], wherein the content of the above chloroprene rubber is 40 to 100% by mass in the above rubber component.

[0024] [7] The rubber composition according to any one of [1] to [6], wherein the above rubber component further contains styrene-butadiene rubber.

[0025] [8] A laminate, the laminate having a reinforcing layer with a metal surface and a rubber layer provided on the above metal surface, the above rubber layer being a vulcanized rubber of the rubber composition according to any one of [1] to [7].

[0026] [9] The laminate according to [8], wherein the above metal surface is a metal surface plated with brass.

[0027]

[10] The laminate according to [8] or [9], wherein the above reinforcing layer is formed of brass-plated wire.

[0028]

[11] A hose, the hose having a reinforcing layer with a metal surface and a rubber layer provided on the above metal surface, the above rubber layer being a vulcanized rubber of the rubber composition according to any one of [1] to [7].

[0029]

[12] The hose according to

[11] is a hose for hydraulic use.

[0030] Advantages of the Invention

[0031] The present invention can provide a rubber composition having excellent adhesion and abrasion resistance between the obtained vulcanized rubber and a reinforcing layer having a metal surface.

[0032] In addition, the present invention can also provide a laminate and a hose. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a partially cutaway perspective view of an embodiment of the hose of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] The present invention will be described in detail below.

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

[0036] In this specification, unless otherwise specified, each component can be used separately for the substances belonging to the component or two or more thereof can be used in combination. When the component contains two or more substances, the content of the component means the total content of the two or more substances.

[0037] In this specification, a case where at least one of the adhesion between the obtained vulcanized rubber and a reinforcing layer having a metal surface and the abrasion resistance is more excellent is sometimes referred to as "the effect of the present invention is more excellent".

[0038] [Rubber Composition]

[0039] The rubber composition of the present invention is a rubber composition as follows:

[0040] containing: based on 100 parts by mass of a rubber component containing chloroprene rubber,

[0041] 5 parts by mass or more and 14 parts by mass or less of silica,

[0042] 1.0 part by mass or less of sulfur, and ethylene thiourea.

[0043] Hereinafter, each component contained in the rubber composition of the present invention will be described in detail.

[0044] [Rubber Component]

[0045] In the rubber composition of the present invention, the rubber component contains chloroprene rubber.

[0046] [Chloroprene Rubber]

[0047] In the rubber composition of the present invention, the chloroprene rubber (CR) contained as a rubber component is not particularly limited as long as it is a polymer formed from monomers containing 2-chlorobutadiene. For example, conventionally known chloroprene rubbers can be cited.

[0048] (Content of chloroprene rubber)

[0049] From the viewpoint of more excellent effects of the present invention, the content of chloroprene rubber is preferably 40 to 100% by mass, more preferably 40 to 70% by mass in the rubber component (total mass).

[0050] (Other rubber components)

[0051] The rubber component may further contain rubber components other than chloroprene rubber (other rubber components).

[0052] As other rubber components, for example, the following can be cited: diene rubbers such as styrene-butadiene rubber (SBR), natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), acrylonitrile-butadiene copolymer rubber (NBR), butyl rubber (IIR), and halogenated butyl rubber (Br-IIR, Cl-IIR).

[0053] From the viewpoint of more excellent effects of the present invention, the rubber component preferably further contains styrene-butadiene rubber (SBR).

[0054] The styrene-butadiene rubber is not particularly limited as long as it is a polymer formed from monomers containing styrene and butadiene. For example, conventionally known SBR can be cited.

[0055] The content of styrene units (styrene content) in the styrene-butadiene rubber is not particularly limited. For the reason of more excellent effects of the present invention, it is preferably 10 to 50% by mass, more preferably 15 to 40% by mass.

[0056] The content of other rubber components (especially styrene-butadiene rubber) in the rubber component is not particularly limited. For the reason of more excellent effects of the present invention, it is preferably 0 to 60% by mass, more preferably 30 to 60% by mass in the rubber component (total mass).

[0057] [Silica]

[0058] The rubber composition of the present invention contains silica.

[0059] The silica is not particularly limited. As silica, for example, the following can be cited: crystalline silica, precipitated silica, amorphous silica (e.g., high-temperature treated silica), fumed silica, calcined silica, precipitated silica, ground silica, and fused silica, etc.

[0060] From the viewpoint of more excellent effects of the present invention, the silica preferably contains acidic silica with a pH less than 7. In the present invention, the pH of the silica can be measured according to JIS K5101-17-2:2004.

[0061] [Content of silica]

[0062] In the rubber composition of the present invention, the content of silica is 5 parts by mass or more and 14 parts by mass or less relative to 100 parts by mass of the rubber component.

[0063] From the viewpoint of more excellent effects of the present invention (especially the adhesiveness to the reinforcing layer), the content of silica is preferably 10 parts by mass or more and 14 parts by mass or less relative to 100 parts by mass of the rubber component.

[0064] [Sulfur]

[0065] The rubber composition of the present invention contains sulfur.

[0066] Sulfur can act as a vulcanizing agent.

[0067] There is no particular limitation on sulfur as long as it can be used as a vulcanizing agent. Examples of sulfur include powdered sulfur, precipitated sulfur, highly dispersed sulfur, surface-treated sulfur, and insoluble sulfur.

[0068] [Content of sulfur]

[0069] In the rubber composition of the present invention, the content of sulfur is 1.0 part by mass or less relative to 100 parts by mass of the rubber component. In the present invention, the content of sulfur relative to 100 parts by mass of the rubber component only needs to exceed 0 part by mass and be 1.0 part by mass or less. In the present invention, the content of sulfur is 1.0 part by mass or less relative to 100 parts by mass of the rubber component, whereby a vulcanized rubber with excellent heat resistance can be obtained.

[0070] When the content of sulfur exceeds 1.0 part by mass relative to 100 parts by mass of the rubber component, the heat resistance of the obtained vulcanized rubber is poor.

[0071] From the viewpoints of more excellent effects of the present invention and excellent heat resistance, the content of sulfur is preferably 0.5 to 0.8 parts by mass relative to 100 parts by mass of the rubber component.

[0072] [Ethylenethiourea]

[0073] The rubber composition of the present invention contains ethylenethiourea.

[0074] Ethylenethiourea (2-mercapto-2-imidazoline) is a compound having the following structure:

[0075] [Chemical formula 1]

[0076]

[0077] (Content of ethylene thiourea)

[0078] From the viewpoint of more excellent effects of the present invention (especially adhesiveness to the reinforcing layer), the content of ethylene thiourea is preferably 0.5 to 1.0 parts by mass relative to 100 parts by mass of the rubber component.

[0079] (Polyol)

[0080] From the viewpoint of more excellent effects of the present invention (especially adhesiveness to the reinforcing layer), the rubber composition of the present invention preferably further contains a polyol having a molecular weight of 300 or less.

[0081] The polyol that can be contained in the rubber composition of the present invention is an alcohol having a molecular weight of 300 or less and having two or more hydroxyl groups.

[0082] For the reason of more excellent adhesiveness, the polyol preferably contains at least one selected from the group consisting of the compounds represented by the following general formula (1) and pentaerythritol.

[0083]

[0084] In the general formula (1), R1 represents a hydrogen atom, a hydroxyl group, or a mono- or polyhydroxyalkyl group, and R2 represents a hydrogen atom or a mono- or polyhydroxyalkyl group. Among them, at least one of R1 and R2 has a hydroxyl group. It should be noted that in the present specification, when R1 has a hydroxyl group, R1 can be a hydroxyl group or any one of the above mono- or polyhydroxyalkyl groups. In addition, when R2 has a hydroxyl group, R2 can be any one of the above mono- or polyhydroxyalkyl groups.

[0085] The mono- or polyhydroxyalkyl group as R1 is an aliphatic hydrocarbon group having one or more hydroxyl groups. The aliphatic hydrocarbon group constituting the above mono- or polyhydroxyalkyl group can be, for example, any of linear and branched forms. As the number of carbon atoms of the above aliphatic hydrocarbon group, for example, 1 to 5 can be cited. The above aliphatic hydrocarbon group can form an ether bond. When the above aliphatic hydrocarbon group forms an ether bond, as the above ether bond, for example, the following structures can be cited: a structure in which the above aliphatic hydrocarbon group is bonded to the main skeleton of the structure represented by the general formula (1) through an ether bond, and a structure in which a plurality of the above aliphatic hydrocarbon groups are bonded through an ether bond. The mono- or polyhydroxyalkyl group as R2 is the same as the mono- or polyhydroxyalkyl group as the above R1.

[0086] In the general formula (1), R1 represents a hydrogen atom, a hydroxyl group, or the above mono- or polyhydroxyalkyl group.

[0087] In the above general formula (1), as the "mono- or polyhydroxyalkyl group" in R1, for example, the following can be cited:

[0088] Hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl, dihydroxyethyl, 1-hydroxypropyl, 2-hydroxypropyl, 3-hydroxypropyl, dihydroxypropyl, trihydroxypropyl, 1-hydroxybutyl, 2-hydroxybutyl, 3-hydroxybutyl, 4-hydroxybutyl, dihydroxybutyl, trihydroxybutyl, tetra-hydroxybutyl, pentahydroxybutyl, 1-hydroxypentyl, 2-hydroxypentyl, 3-hydroxypentyl, 4-hydroxypentyl, 5-hydroxypentyl, dihydroxypentyl, trihydroxypentyl, tetra-hydroxypentyl, pentahydroxypentyl, hydroxymethoxymethyl, hydroxyethoxyethyl, dihydroxypropoxymethyl, dihydroxypropoxyethyl, trihydroxypropoxymethyl, and trihydroxypropoxyethyl, etc. The above-mentioned mono- or polyhydroxyalkyl groups can be bonded to the main skeleton of the structure represented by the general formula (1) through an oxygen atom.

[0089] In the general formula (1), R2 represents a hydrogen atom, or the above-mentioned mono- or polyhydroxyalkyl group. It should be noted that when R2 is a hydrogen atom, R1 has a hydroxyl group (that is, in the above case, R1 may be a hydroxyl group or the above-mentioned mono- or polyhydroxyalkyl group).

[0090] In the above general formula (1), as the "mono- or polyhydroxyalkyl group" in R2, for example, the same examples as the "mono- or polyhydroxyalkyl group" in R1 can be listed.

[0091] As the compound represented by the above general formula (1), for example, ethylene glycol, propylene glycol, butylene glycol, pentylene glycol, diethylene glycol, triethylene glycol, glycerol, 1,2,6-trihydroxyhexane, diglycerol, trimethylolpropane, sorbitol, and hexanetriol, etc. can be cited.

[0092] For the reason that the effects of the present invention (especially the adhesiveness to the reinforcing layer) are more excellent, the polyol preferably contains at least one selected from the group consisting of ethylene glycol, diethylene glycol, glycerol, hexanetriol, diglycerol, and sorbitol, and more preferably contains glycerol.

[0093] For the reason that the effects of the present invention are more excellent, the molecular weight of the above polyol is preferably 50 to 300, and more preferably 70 to 300.

[0094] The boiling point of the polyol is not particularly limited, and is preferably 100 to 400 °C, and more preferably 100 to 300 °C. It should be noted that the above boiling point refers to the value under the condition of 1 atm.

[0095] When the rubber composition of the present invention further contains the above polyol, the content of the above polyol is preferably 1 part by mass or more, and more preferably 1.0 to 4.0 parts by mass, based on 100 parts by mass of the rubber component.

[0096] (Optional component)

[0097] The rubber composition of the present invention may further contain additives. Examples of the additives include: filler materials other than silica; zinc oxide; crosslinking promoting aids such as stearic acid; acid absorbents such as magnesium oxide; anti-aging agents such as N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD); waxes; processing aids; oils; vulcanization accelerators such as sulfur-containing vulcanization accelerators and guanidine vulcanization accelerators; antistatic agents, flame retardants, and vulcanization inhibitors. The types and contents of the respective additives can be appropriately selected.

[0098] Examples of the filler materials other than silica include carbon black. When the rubber composition of the present invention further contains carbon black, the carbon black preferably contains ISAF carbon black and / or FEF carbon black.

[0099] When the rubber composition of the present invention further contains carbon black, the content of the carbon black can be, for example, 30 to 150 parts by mass relative to 100 parts by mass of the rubber component.

[0100] (Preparation method of rubber composition)

[0101] The rubber composition of the present invention can be manufactured by a conventionally well-known manufacturing method. Examples of the method include: mixing the above-mentioned respective components using a closed mixer such as a Banbury mixer and a kneader, a roll mixer such as a roll, an extruder, and a twin-screw extruder.

[0102] (Vulcanized rubber)

[0103] By vulcanizing the rubber composition of the present invention, a vulcanized rubber (cured product) of the rubber composition of the present invention can be obtained.

[0104] (Vulcanization of rubber composition)

[0105] The method and conditions for vulcanizing the rubber composition of the present invention are not particularly limited. As the vulcanization temperature, 130 to 180 °C is preferable. As the vulcanization time, it can be set to, for example, 30 minutes or more and 240 minutes or less.

[0106] Examples of the method for vulcanizing the rubber composition of the present invention include: steam vulcanization (a method of enclosing in a high-pressure container and crosslinking in a steam autoclave), oven vulcanization (a method of vulcanizing the rubber composition covered with nylon cloth or the like in a hot air drying furnace), pressure vulcanization, steam heating vulcanization, and hot water vulcanization.

[0107] From the viewpoint of productivity, the method for vulcanizing the rubber composition of the present invention preferably uses oven vulcanization, and this oven vulcanization is a continuous treatment.

[0108] [Laminate]

[0109] The laminate of the present invention is a laminate having a reinforcing layer with a metal surface and a rubber layer provided on the metal surface, and the rubber layer is a vulcanized rubber of the rubber composition of the present invention.

[0110] In the laminate of the present invention, the reinforcing layer is adjacent to the rubber layer, and the reinforcing layer (the metal surface of the reinforcing layer) is directly bonded to the rubber layer.

[0111] [Reinforcing layer with a metal surface]

[0112] The laminate of the present invention has a reinforcing layer with a metal surface.

[0113] From the viewpoint of more excellent effects of the present invention, the metal surface is preferably a metal surface plated with brass.

[0114] In addition, from the viewpoint of more excellent effects of the present invention, the reinforcing layer is preferably formed of brass-plated wires.

[0115] As the form of the material (such as brass-plated wires) used in the reinforcing layer, for example, a form woven into a spiral structure or a braid structure can be cited.

[0116] [Rubber layer]

[0117] The laminate of the present invention has a rubber layer.

[0118] In the laminate of the present invention, the rubber layer is provided on the metal surface (i.e., on the reinforcing layer) of the reinforcing layer.

[0119] The rubber layer is not particularly limited as long as it is a layer of vulcanized rubber of the rubber composition of the present invention.

[0120] (Different layers)

[0121] The laminate of the present invention may further have a layer different from the above-mentioned reinforcing layer and the above-mentioned rubber layer. As the above-mentioned different layer, for example, a different rubber layer (conveniently also referred to as the second rubber layer) disposed on the opposite side of the rubber layer (a layer of vulcanized rubber of the rubber composition of the present invention. For convenience, it is also referred to as the first rubber layer) on the above-mentioned reinforcing layer can be cited.

[0122] The second rubber layer is not particularly limited. For example, a vulcanized rubber of the rubber composition of the present invention can be cited.

[0123] The second rubber layer may be the same as or different from the first rubber layer.

[0124] (Manufacturing method of the laminate)

[0125] As a method for manufacturing the laminate of the present invention, for example, the following method can be cited: by sequentially overlapping the reinforcing layer and the rubber composition of the present invention and vulcanizing them in the overlapped state to manufacture the laminate of the present invention. The vulcanization during the manufacture of the laminate can be the same as the above-mentioned "(vulcanization of the rubber composition)".

[0126] When the laminate of the present invention further has a layer different from the above-mentioned reinforcing layer and the above-mentioned rubber layer, it is only necessary to further use a material corresponding to the different layer to manufacture the laminate. When the different layer is a second rubber layer, the rubber composition for forming the second rubber layer is not particularly limited. For example, the rubber composition of the present invention can be cited. In addition, the rubber composition for forming the second rubber layer can be the same as or different from the rubber composition for forming the first rubber layer.

[0127] The laminate of the present invention can be applied to, for example, a hose. Specifically, for example, it can be applied to a high-pressure or hydraulic hose.

[0128] The laminate of the present invention can be used as at least a part of a hose.

[0129] [Hose]

[0130] The hose of the present invention is a hose having a reinforcing layer with a metal surface and a rubber layer provided on the above-mentioned metal surface, and the above-mentioned rubber layer is a vulcanized rubber of the rubber composition of the present invention.

[0131] In the hose of the present invention, the above-mentioned reinforcing layer is adjacent to the above-mentioned rubber layer, and the reinforcing layer (the metal surface of the reinforcing layer) is directly bonded to the rubber layer.

[0132] [Reinforcing layer with a metal surface]

[0133] The hose of the present invention has a reinforcing layer with a metal surface.

[0134] The reinforcing layer in the hose of the present invention corresponds to and is the same as the reinforcing layer in the laminate of the present invention.

[0135] The thickness of the reinforcing layer is not particularly limited, and can be set to, for example, 0.3 to 1 mm.

[0136] [Rubber layer]

[0137] The hose of the present invention has a rubber layer.

[0138] In the hose of the present invention, the rubber layer is provided on the metal surface of the reinforcing layer (i.e., on the reinforcing layer).

[0139] The above-mentioned rubber layer is not particularly limited as long as it is a layer of vulcanized rubber of the rubber composition of the present invention.

[0140] The rubber layer in the hose of the present invention corresponds to and is the same as the rubber layer in the laminate of the present invention.

[0141] The thickness of the rubber layer is not particularly limited and can be set, for example, to 0.2 to 3 mm.

[0142] The rubber layer in the hose of the present invention can be the inner rubber layer or the outer rubber layer in the hose. As a preferred embodiment, for example, the rubber layer in the hose of the present invention is at least the outer rubber layer of the hose.

[0143] (Different layers)

[0144] The hose of the present invention can further have a layer different from the above-mentioned reinforcing layer and the above-mentioned rubber layer. As the above-mentioned different layer, for example, a different rubber layer (conveniently also referred to as the inner rubber layer) disposed on the side opposite to the above-mentioned rubber layer (conveniently also referred to as the outer rubber layer) on the above-mentioned reinforcing layer can be cited. The inner rubber layer is not particularly limited. For example, a vulcanized rubber of the rubber composition of the present invention can be cited. The outer rubber layer and the inner rubber layer can be the same or different.

[0145] When the hose of the present invention further has an inner rubber layer, the thickness of the inner rubber layer is not particularly limited and can be set, for example, to 0.2 to 3 mm.

[0146] In addition, when the hose of the present invention further has an inner rubber layer, the above-mentioned outer rubber layer corresponds to the first rubber layer in the laminate of the present invention, and the above-mentioned inner rubber layer corresponds to the second rubber layer in the laminate of the present invention.

[0147] (Manufacturing method of the hose)

[0148] As a manufacturing method of the hose of the present invention, for example, the following method can be cited: The hose of the present invention is manufactured by sequentially overlapping the reinforcing layer and the rubber composition of the present invention and performing vulcanization in the overlapped state. The vulcanization during the manufacture of the hose can be the same as the above-mentioned "(Vulcanization of the rubber composition)".

[0149] When the hose of the present invention further has a layer different from the above-mentioned reinforcing layer and the above-mentioned rubber layer (for example, an inner rubber layer), it is only necessary to further use a material corresponding to the above-mentioned different layer to manufacture the hose. When the different layer is an inner rubber layer, the rubber composition for forming the inner rubber layer is not particularly limited. For example, the rubber composition of the present invention can be cited. It should be noted that the rubber compositions for forming the outer rubber layer and the inner rubber layer can be the same or different.

[0150] The hose of the present invention can be applied to, for example, high-pressure or hydraulic hoses.

[0151] The configuration 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.

[0152] Figure 1 It is a partially cutaway perspective view of an embodiment of the hose of the present invention.

[0153] Figure 1 In Figure 1 , the hose 1 is formed in a cylindrical shape and has: an inner rubber layer 11 through which fluid passes inside, a reinforcing layer 12 provided on the outer side of the inner rubber layer 11, and an outer rubber layer 13 provided on the outer side of the reinforcing layer 12. Here, the reinforcing layer 12 has a metal surface. In addition, the inner rubber layer 11 and / or the outer rubber layer 13 can be formed using the above-described composition of the present invention. The reinforcing layer 12 is disposed sandwiched between the inner rubber layer 11 and the outer rubber layer 13. The inner rubber layer 11, the reinforcing layer 12, and the outer rubber layer 13 are bonded and fixed by vulcanization of the inner rubber layer 11 and the outer rubber layer 13.

[0154] Examples

[0155] Hereinafter, the present invention will be specifically described by showing examples. However, the present invention is not limited to these examples.

[0156] <Manufacture of rubber composition>

[0157] Each component in the following first table was used according to the composition (parts by mass) shown in the table, and they were mixed using a blender to manufacture each rubber composition.

[0158] It should be noted that in the first table, the amount of ethylene thiourea is the actual amount of ethylene thiourea. In addition, in the first table, the amount of sulfur is the actual amount of sulfur.

[0159] <Manufacture of hose>

[0160] First, on a mandrel with an outer diameter of 34 mm, brass-plated wires were wound into a braid shape to form a reinforcing layer having a metal surface. Next, an uncured sheet with a thickness of 2.5 mm prepared from each of the obtained rubber compositions was adhered to the metal surface of the reinforcing layer. Further, a curing tape (protective cloth) made of nylon 66 was wound so as to cover the outside of the uncured sheet, and vulcanization was carried out by an oven vulcanization method (in an atmospheric oven at 150 °C for 135 minutes). Thus, a hose having a reinforcing layer with a metal surface and a rubber layer (outer rubber layer) provided on the metal surface of the reinforcing layer was obtained.

[0161] <Evaluation of adhesiveness>

[0162] For the obtained hose, the adhesive force (kN / m) and the rubber adhesion rate (%) were evaluated. The results are shown in Table 1 (before the damp heat aging test).

[0163] Here, the adhesive force (kN / m) refers to the magnitude (kN) of the force per unit width (m) required to peel the outer rubber layer from the reinforcing layer (peeling speed: 50 mm / minute).

[0164] In addition, the rubber adhesion rate refers to the ratio of the outer rubber layer remaining on the surface of the reinforcing layer when the outer rubber layer is peeled off, and represents the area ratio of the remaining rubber layer to the entire surface area of the reinforcing layer as a percentage.

[0165] The values of the adhesive force (kN / m) and the rubber adhesion rate (%) are the average values obtained by measuring 10 times.

[0166] · Evaluation criteria for the adhesion of vulcanized rubber to a reinforcing layer with a metal surface

[0167] In the present invention, if the adhesive force is 3.5 kN / m or more and the rubber adhesion rate is 60% or more, the adhesion of the vulcanized rubber to the reinforcing layer with a metal surface is evaluated as excellent. If the adhesive force is greater than 3.5 kN / m and / or the rubber adhesion rate is greater than 60%, the adhesion of the vulcanized rubber to the reinforcing layer with a metal surface is more excellent.

[0168] On the other hand, if the adhesive force is less than 3.5 kN / m or if the rubber adhesion rate is less than 60%, the adhesion of the vulcanized rubber to the reinforcing layer with a metal surface is evaluated as poor.

[0169] <Abrasion resistance>

[0170] · Preparation of test pieces

[0171] For each of the rubber compositions manufactured as described above, a disk-shaped test piece with a diameter of 63.5 ± 0.5 mm, a thickness of 12.7 ± 0.5 mm, and a central hole of 12.7 ± 0.1 mm was prepared by vulcanizing for 45 minutes under the conditions of 148°C and a surface pressure of 3.0 MPa using a compression molding machine.

[0172] · Abrasion test

[0173] Using the above disk-shaped test piece, the abrasion loss (ml) was measured in accordance with JIS K6264-2:2005 (Akron abrasion test method A, additional force 27 N, inclination 15 degrees, test rotation speed 1,000 times).

[0174] · Evaluation criteria for abrasion resistance

[0175] If the abrasion loss measured as described above is 0 to 0.14 ml, the abrasion resistance of the obtained vulcanized rubber is evaluated as excellent and represented as "〇".

[0176] On the other hand, if the abrasion loss exceeds 0.14 ml, the abrasion resistance of the obtained vulcanized rubber is evaluated as poor and represented as "×".

[0177] [Table 1]

[0178]

[0179]

[0180] [Table 2]

[0181]

[0182]

[0183] [Table 3]

[0184]

[0185]

[0186] The details of each component shown in Table 1 are as follows.

[0187] (Rubber component)

[0188] SBR: Trade name "Nipol 1502", manufactured by Zeon Co., Ltd., Japan, emulsion polymerized SBR, bound styrene content 23.5% by mass, Mooney viscosity (ML 1+4 , 100℃)52, oil-free type

[0189] CR: Trade name "DenkaChloroprene S-41", manufactured by Denki Kagaku Kogyo Co., Ltd., non-sulfur modified chloroprene rubber, Mooney viscosity (ML 1+4 , 100℃)48

[0190] FEF carbon black: Trade name "HTC#100", manufactured by Shin Sun Chemical Carbon Co., Ltd. (silicon dioxide)

[0191] Silica: Trade name "Nipsil AQ", manufactured by Tosoh Silica Co., Ltd., pH 6.4

[0192] Clay: Trade name "Suprex Clay", manufactured by Kentucky-Tennessee Clay Company

[0193] Talc: Trade name "MISTRON VAPOR", manufactured by Imerys

[0194] Calcium carbonate: Heavy calcium carbonate, manufactured by MARUO CALCIUM

[0195] Zinc oxide: Zinc oxide JIS#3, manufactured by Shodo Chemical Industry Co., Ltd.

[0196] · Stearic acid: manufactured by NOF Corporation

[0197] · Magnesium oxide: trade name “Kyowamag 150”, acid absorbent manufactured by Kyowa Chemical Industry Co., Ltd.

[0198] · Anti-aging agent 6C: ozone-proof agent (anti-aging agent). Trade name “Ozonone 6C”, manufactured by Seiko Chemical Co., Ltd. (sulfur)

[0199] · Sulfur: manufactured by Hosoi Chemical Industry Co., Ltd.

[0200] · Oil (VIVATEC500): T-DAE oil, manufactured by H&R Company (polyol)

[0201] · Glycerol: molecular weight: 92, boiling point: 290 °C, refined glycerol, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd. (ethylene thiourea)

[0202] · Ethylene thiourea: trade name “SANMIX 22-80E”, manufactured by Sanshin Chemical Industry Co., Ltd. The concentration of ethylene thiourea in the above product is 80% by mass. It should be noted that the actual amount of ethylene thiourea is recorded in the “Ethylene thiourea” column of the first table.

[0203] · Vulcanization accelerator CZ: N-cyclohexyl-2-benzothiazole sulfenamide. Nocceler CZ-G manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0204] · Vulcanization accelerator DPG: 1,3-dimethylguanidine. Soxinol D-G manufactured by Sumitomo Chemical Co., Ltd.

[0205] · Vulcanization accelerator TS: tetramethylthiuram monosulfide, Sunseller TS-G manufactured by Sanshin Chemical Industry Co., Ltd.

[0206] According to the results shown in the first table, in Comparative Examples 1 to 5 and 10 without silica, the adhesion between the obtained vulcanized rubber and the reinforcing layer is poor.

[0207] In Comparative Example 6 where the silica content does not meet the specified amount, the abrasion resistance of the obtained vulcanized rubber is poor.

[0208] In Comparative Examples 7 to 9 without silica and containing clay, talc or calcium carbonate as a substitute, the abrasion resistance of the obtained vulcanized rubber is poor.

[0209] In Comparative Examples 11 and 14 without ethylene thiourea, the adhesion between the obtained vulcanized rubber and the reinforcing layer is poor

[0210] In Comparative Examples 12 and 13 without silica and ethylene thiourea, the adhesion between the obtained vulcanized rubber and the reinforcing layer is poor.

[0211] In Comparative Example 15 which does not contain silica, contains clay as a substitute, and does not contain ethylene thiourea, the adhesion of the obtained vulcanized rubber to the reinforcing layer and the abrasion resistance of the obtained vulcanized rubber are poor.

[0212] In contrast, regarding the rubber composition of the present invention, the adhesion of the obtained vulcanized rubber to the reinforcing layer having a metal surface and the abrasion resistance are excellent.

[0213] In addition, regarding the laminate of the present invention, the adhesion of the vulcanized rubber to the reinforcing layer having a metal surface and the abrasion resistance are excellent.

[0214] Regarding the hose of the present invention, the adhesion of the vulcanized rubber to the reinforcing layer having a metal surface and the abrasion resistance are excellent.

[0215] (Synergistic effect of adhesion and maintenance of excellent abrasion resistance brought about by the combined use of silica and ethylene thiourea)

[0216] The increase in the rubber adhesion rate of Example 1 based on Comparative Example 12 (85 - 5 = 80%) far exceeds the sum of the rubber adhesion effects of Comparative Examples 1 and 11 based on Comparative Example 12 (25 - 5 + 10 - 5 = 25%). In addition, compared with Comparative Example 12, Example 1 can maintain the excellent abrasion resistance of Comparative Example 12.

[0217] The increase in the rubber adhesion rate and the maintenance of the abrasion resistance of Example 12 based on Comparative Example 13 also obtained the same results as above.

[0218] In this way, in the rubber composition of the present invention, the synergistic effect of adhesion brought about by the combined use of silica and ethylene thiourea is significant, and excellent abrasion resistance can be maintained even when silica and ethylene thiourea are used in combination.

[0219] On the other hand, compared with Comparative Example 13, Comparative Example 7 in which clay and ethylene thiourea are used in combination cannot maintain the excellent abrasion resistance of Comparative Example 13.

[0220] Description of reference numerals

[0221] 1: Hose

[0222] 11: Inner rubber layer

[0223] 12: Reinforcing layer

[0224] 13: Outer rubber layer

Claims

1. A rubber composition, the rubber composition containing: per 100 parts by mass of a rubber component containing chloroprene rubber, 5 parts by mass or more and 14 parts by mass or less of silica, 1.0 part by mass or less of sulfur, and ethylene thiourea.

2. The rubber composition according to claim 1, wherein, Per 100 parts by mass of the rubber component, the content of the ethylene thiourea is 0.5 to 1.0 part by mass.

3. The rubber composition according to claim 1 or 2, wherein Per 100 parts by mass of the rubber component, the content of the silica is 10 parts by mass or more.

4. The rubber composition according to any one of claims 1 to 3, the rubber composition further containing a polyol having a molecular weight of 300 or less, Per 100 parts by mass of the rubber component, the content of the polyol is 1 part by mass or more.

5. The rubber composition according to any one of claims 1 to 4, wherein, Per 100 parts by mass of the rubber component, the content of the sulfur is 0.5 to 0.8 part by mass.

6. The rubber composition according to any one of claims 1 to 5, wherein, The content of the chloroprene rubber is 40 to 100% by mass in the rubber component.

7. The rubber composition according to any one of claims 1 to 6, wherein, The rubber component further contains styrene-butadiene rubber.

8. A laminate, the laminate including a reinforcing layer having a metal surface and a rubber layer provided on the metal surface, the rubber layer being a vulcanized rubber of the rubber composition according to any one of claims 1 to 7.

9. The laminate according to claim 8, wherein, The metal surface is a brass-plated metal surface.

10. The laminate according to claim 8 or 9, wherein, The reinforcing layer is formed of brass-plated wire.

11. A hose, the hose including a reinforcing layer having a metal surface and a rubber layer provided on the metal surface, the rubber layer being a vulcanized rubber of the rubber composition according to any one of claims 1 to 7.

12. The hose according to claim 11, the hose being a hydraulic hose.

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