Marine hose and manufacturing method thereof

Abstract

To provide a marine hose which includes a desired thickness of a urethane layer on an outermost peripheral surface while having good wear resistance and can improve productivity, and a method of manufacturing the marine hose.SOLUTION: A hose body part 3 is vulcanized by steam-vulcanizing a molding which is laminated with a sheet-shaped material 11T composed of a rubber composition containing a millable urethane polymer within a vulcanization can 14 on a cylindrical outer peripheral face in which cylindrical reinforcing layers 5, 6 and 7 are embedded between a cylindrical non-vulcanized inner peripheral layer 4 and a cover layer 9. The sheet-shaped material 11T is formed on a urethane inner peripheral layer 11, and a liquid material 12T is formed on a urethane outer peripheral layer composed of a rubber composition containing a castable urethane polymer 12 by applying the liquid material 12T to an outer peripheral face of the urethane inner peripheral layer 11 and aging the liquid material. A desired thickness of a urethane layer 10 having a lamination structure in which the urethane inner peripheral layer 11a and the urethane outer peripheral layer 12 are sequentially laminated is provided on an outer peripheral face of the vulcanized hose body part 3.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a marine hose and a method for manufacturing the same, and more particularly to a marine hose that can improve productivity of a marine hose having good abrasion resistance and a urethane layer of a desired thickness on its outermost surface, and a method for manufacturing the same.

[0002] Marine hoses are used to transport fluids such as crude oil by sea (see, for example, Patent Document 1). Some marine hoses have a urethane layer on the outermost surface to suppress wear on the outermost surface.

[0003] This urethane layer is formed, for example, by applying a liquid material made of a rubber composition containing a castable urethane polymer to the outer surface of the hose body and then allowing it to mature. Using this rubber composition has the advantage of allowing a urethane layer with excellent abrasion resistance to be formed without a vulcanization process. However, because it is a liquid material, it cannot be applied thickly in one go, and repeated applications are required to achieve the desired thickness. Furthermore, a very long maturation time is required for the liquid material to harden. Therefore, there is room for improvement in the productivity of marine hoses with excellent abrasion resistance and a urethane layer of the desired thickness on the outermost surface. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-122672 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a marine hose that can improve productivity in producing a marine hose having good abrasion resistance and a urethane layer of a desired thickness on its outermost surface, and a method for producing the same. [Means for solving the problem]

[0006] In order to achieve the above object, the marine hose of the present invention is a marine hose having a urethane layer on the outermost surface thereof, the urethane layer being made of a rubber composition containing a castable urethane polymer. (However, rubber compositions containing millable urethane polymers are excluded.) and a rubber composition comprising a millable urethane polymer disposed on the inner peripheral side of the urethane outer peripheral layer. (However, rubber compositions containing castable urethane polymers are excluded.) It is characterized by a laminated structure with an inner urethane layer made of

[0007] The method for manufacturing a marine hose of the present invention is characterized in that, in a method for manufacturing a marine hose having a urethane layer on its outermost surface, a cylindrical hose main body is molded in which a cylindrical reinforcing layer is embedded between a cylindrical unvulcanized inner layer and a cover layer, and a molded body in which a sheet-like material made of a rubber composition containing a castable urethane polymer is laminated on the outer surface of the hose main body, is placed inside a vulcanizing can and steam vulcanized to vulcanize the hose main body, and the sheet-like material is formed into a urethane inner layer, and a liquid material made of a rubber composition containing a castable urethane polymer is applied to the outer surface of the urethane inner layer and matured to form the liquid material into a urethane outer layer, and the urethane layer is provided on the outer surface of the vulcanized hose main body in a laminated structure in which the urethane inner layer and the urethane outer layer are laminated in order. [Effects of the Invention]

[0008] According to the present invention, the inner urethane layer can be formed by laminating and steam-vulcanizing the sheet-like material made of a rubber composition containing a millable urethane polymer, which is advantageous for achieving a desired layer thickness in a short period of time. The outer urethane layer can be formed by applying and maturing a liquid material made of a rubber composition containing a castable urethane polymer, which ensures excellent abrasion resistance. Therefore, by forming the urethane layer into a laminate structure consisting of the outer urethane layer and the inner urethane layer, the outer surface of the urethane layer can achieve excellent abrasion resistance and the urethane layer can be easily formed to a desired thickness. This is advantageous for efficiently manufacturing marine hoses with a urethane layer of desired thickness and excellent abrasion resistance on the outermost surface. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is an explanatory diagram illustrating a marine hose according to the present invention. [Figure 2] 2 is an explanatory diagram illustrating an enlarged vertical cross-sectional view of the upper half of the periphery of one end portion in the longitudinal direction of the marine hose of FIG. 1.

[0023] FIG. [Figure 3] 2 is an explanatory diagram illustrating a cross-sectional structure of a marine hose taken along the line AA in FIG. 1. [Figure 4] 4 is an explanatory diagram illustrating an enlarged longitudinal cross-sectional view of the urethane layer and its periphery in FIG. 3. FIG. [Figure 5] 5 is an explanatory diagram showing a modified example of the urethane layer of FIG. 4. [Figure 6] 2 is an explanatory view illustrating a step of laminating a sheet-shaped material on the outer peripheral surface of the hose main body when manufacturing the marine hose of FIG. 1. FIG. [Figure 7] 7 is an explanatory view illustrating a process of steam vulcanizing a hose body formed by laminating the sheet-shaped materials of FIG. 6. FIG. [Figure 8] 8 is an explanatory view illustrating the hose body and the inner circumferential urethane layer vulcanized by the process of FIG. 7. [Figure 9] 9 is an explanatory diagram illustrating a process of applying a liquid material to the outer peripheral surface of the inner peripheral urethane layer of FIG. 8. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a marine hose and a method for manufacturing the same according to the present invention will be described based on an embodiment shown in the drawings

[0011] The embodiment of the marine hose 1 illustrated in Figures 1 to 4 has a cylindrical hose body 3 in which cylindrical reinforcing layer groups 5, 6, and 7 are embedded between a cylindrical inner surface layer 4 and a cover layer 9, and a urethane layer 10 laminated on the outer peripheral surface of the hose body 3. The urethane layer 10 forms the outermost layer surface of the marine hose 1. The reinforcing layer groups 6 and 7 can be provided as appropriate based on the pressure resistance performance required of the marine hose 1, etc.

[0012] The marine hose 1 has connecting ends 2 at both longitudinal ends for connecting another marine hose 1. The connecting ends 2 have a nipple 2b extending in the longitudinal direction of the marine hose 1 and a flange 2a joined to one longitudinal end of the nipple 2b. Typically, for example, around eight to ten marine hoses 1 are connected together for use. The dashed-dotted line CL in the figure is a centerline that passes through the center of the cross section of the marine hose 1 and extends in the longitudinal direction of the hose. Note that while Figure 3 shows only one-quarter of the cross section of the marine hose 1, the remaining area not shown (three-quarters) has the same structure.

[0013] Describing the hose main body 3 extending between the connecting end portions 2 in detail, the inner surface layer 4, inner first reinforcing layer group 5, reinforcing wire layer 6r, inner second reinforcing layer group 6, outer reinforcing layer group 7, buoyancy layer 8, and cover layer 9 are layered coaxially, in order from the inner periphery, around the cylindrical flow path 1a (i.e., centered on the center line CL). The inner first reinforcing layer group 5, inner second reinforcing layer group 6, and outer reinforcing layer group 7 are fixed to the nipple 2b by nipple wires 5w, 6w, and 7w at one end of each, and by a fixing ring 2c protruding from the outer peripheral surface of the nipple 2b, etc.

[0014] The inner peripheral surface of the inner surface layer 4 becomes the flow path 1a for the fluid L. Examples of the fluid L include crude oil, gasoline, and LPG. An appropriate material is used for the inner surface layer 4 depending on the type of fluid L. When the fluid L is crude oil or the like, the inner surface layer 4 is formed from nitrile rubber or the like, which has excellent oil resistance.

[0015] The first inner reinforcing layer group 5 is configured by laminating a plurality of cord reinforcing layers. The number of cord reinforcing layers is set appropriately as required, for example, about 4 to 30 layers. Each cord reinforcing layer is formed by arranging a large number of rubber-coated reinforcing cords in parallel.

[0016] In each cord-reinforced layer, a large number of reinforcing cords extend at a predetermined angle relative to the center line CL. The reinforcing cords in adjacent vertically stacked cord-reinforced layers are arranged so that the reinforcing cords are inclined in opposite directions and cross each other. The reinforcing cords may be resin fiber cords made of polyester, polyketone, aramid, vinylon, nylon, or the like, which are commonly used in marine hoses, or steel cords.

[0017] Each cord reinforcement layer is covered with a thin rubber layer for adhesion, and adjacent cord reinforcement layers are bonded to each other via this thin rubber layer. The inner peripheral surface of the first inner reinforcement layer group 5 and the outer peripheral surface of the inner layer 4 are in contact with each other and bonded to each other.

[0018] The reinforcing wire layer 6r is formed by spirally winding reinforcing wires around the outer peripheral surface of the first inner reinforcing layer group 5 at intervals in the longitudinal direction of the marine hose 1. The reinforcing wire layer 6r is also covered with an adhesive rubber layer. The outer peripheral surface of the inner first reinforcing layer group 5 and the outer peripheral surface of the reinforcing wire layer 6r are abutted and joined. The reinforcing wire layer 6r can be provided optionally. The reinforcing wire layer 6r can also be disposed inside the first inner reinforcing layer group 5.

[0019] The second inner reinforcing layer group 6 and the outer reinforcing layer group 7 each have substantially the same structure as the first inner reinforcing layer group 5, and are configured by laminating a plurality of cord reinforcing layers. The inner circumferential surface of the second inner reinforcing layer group 6 and the outer circumferential surface of the reinforcing wire layer 6r are abutted and joined together. The outer reinforcing layer group 7 is a reinforcing layer that supports the inner reinforcing layer groups 5, 6, and resists the impact force (internal pressure) that occurs in the marine hose 1 if the inner reinforcing layer groups 5, 6 are damaged. The inner circumferential surface of the outer reinforcing layer group 7 and the outer circumferential surface of the second inner reinforcing layer group 6 are abutted and joined together.

[0020] The buoyancy layer 8 is formed from a material such as sponge rubber or polyurethane foam that exerts buoyancy to keep the marine hose 1 afloat on the sea surface. The thickness of the buoyancy layer 8 (thickness other than at both longitudinal ends) varies depending on the size of the marine hose 1, the required buoyancy, etc., but is, for example, approximately 60 mm to 300 mm. The outer peripheral surface of the outer reinforcing layer group 7 and the inner peripheral surface of the buoyancy layer 8 are abutted and joined. This marine hose 1 is of a floating type and is therefore provided with the buoyancy layer 8, but in the case of a submarine type marine hose 1, the buoyancy layer 8 is omitted.

[0021] The cover layer 9 is made of a water-impermeable material such as rubber. The outer peripheral surface of the buoyancy layer 8 and the inner peripheral surface of the cover layer 9 are abutted and joined, and the outer peripheral surface of the cover layer 9 and the inner peripheral surface of the urethane layer 10 are abutted and joined. To ensure good bonding with the urethane layer 10, the cover layer 9 should preferably contain NBR rubber, which has good adhesion to urethane, as its main component.

[0022] As shown in Figure 4, the urethane layer 10 has a laminated structure of an outer urethane layer 12 and an inner urethane layer 11. The thickness of the urethane layer 10 is, for example, 3 mm to 10 mm. In this embodiment, the urethane layer 10 extends continuously over the entire length of the hose body 3, but it may be provided only within a necessary range in the longitudinal direction of the hose body 3. For example, the urethane layer 10 may be provided only at both ends of the hose body 3 in the longitudinal direction, which are subject to the most severe wear, or at least within a range that includes both ends.

[0023] The urethane inner circumferential layer 11 is laminated on the outer peripheral surface of the hose body 3 (cover layer 9). The urethane inner circumferential layer 11 is formed by curing a rubber composition containing millable urethane polymer. The rubber composition containing millable urethane polymer before curing is cured by vulcanization like general unvulcanized rubber.

[0024] Various known rubber compositions containing millable urethane polymers can be used. An example of the composition is 100 parts by mass of urethane polymer, 50 parts by mass of carbon black or silica, 30 parts by mass of plasticizer, and 5 parts by mass of vulcanizing agent. The type of urethane polymer and the types of compounding ingredients, as well as their compounding ratios, are determined appropriately depending on the required durability (wear resistance), etc.

[0025] The thickness of inner urethane layer 11 is, for example, 2 mm or more, which is greater than or equal to the thickness of outer urethane layer 12. The thickness of inner urethane layer 11 is more preferably 60% or greater than the thickness of urethane layer .

[0026] The outer urethane layer 12 is laminated on the outer peripheral surface of the inner urethane layer 11, and the outer peripheral surface of the inner urethane layer 11 and the inner peripheral surface of the outer urethane layer 12 are abutted and bonded. The outer urethane layer 12 is formed by curing a rubber composition containing a castable urethane polymer. A rubber composition containing a liquid millable urethane polymer cures by aging (aging) at room temperature, so a vulcanization process for curing is not required. The thickness of the outer urethane layer 12 is, for example, 0.5 mm or more and 2 mm or less.

[0027] Various known rubber compositions containing millable urethane polymers can be used. An example of the composition is 100 parts by mass of urethane polymer, 50 parts by mass of carbon black or silica, 30 parts by mass of plasticizer, and 5 parts by mass of vulcanizing agent. The type of urethane polymer and the types of compounding ingredients, as well as their compounding ratios, are determined appropriately depending on the required durability (wear resistance), etc.

[0028] The color of the outer urethane layer 12 and the color of the inner urethane layer 11 laminated adjacent to the outer urethane layer 12 can be the same or different. If the two colors are different, at least one of the hue, saturation, and brightness should be different to make them easily distinguishable at a glance. For example, one color should be red, orange, or yellow, and the other black, gray, brown, or blue.

[0029] As shown in FIG. 5, the inner urethane layer 11 can have a laminated structure in which multiple layers 11a, 11b of different colors are stacked. For example, the inner urethane layers 11a, 11b can be made different in at least one of hue, saturation, and brightness so that they can be easily distinguished at a glance. For example, one layer can be red, orange, or yellow, and the other can be black, gray, brown, or blue. In this case, it is preferable that the color of the inner urethane layer 11b on the inner side be a color that is easily distinguishable from the color of the outer urethane layer 12.

[0030] Next, an example of a procedure for manufacturing this marine hose 1 will be described with reference to FIGS.

[0031] In the manufacturing process of the marine hose 1, the materials forming the above-mentioned inner surface layer 4, inner first reinforcing layer group 5, reinforcing wire layer 6r, inner second reinforcing layer group 6, outer reinforcing layer group 7, buoyancy layer 8, and cover layer 9 are sequentially stacked coaxially on the outer peripheral side of the mandrel 13 around which the connecting end portion 2 is fitted. In this way, a cylindrical hose main body 3 is formed in which the cylindrical reinforcing layers 5, 6, and 7 are embedded between the cylindrical unvulcanized inner surface layer 4 and cover layer 9.

[0032] Next, as shown in FIG. 6, a sheet material 11T made of a rubber composition containing an unvulcanized millable urethane polymer is laminated onto the outer surface of the cylindrical hose body 3 to form a molded body. A sheet material 11T of a predetermined thickness is simply wrapped spirally around the outer surface of the hose body 3 (cover layer 9) over a required area. A sheet material 11T of a predetermined thickness is used depending on the thickness of the inner urethane layer 11 to be formed. When the inner urethane layer 11 is thick, the sheet material 11T of a predetermined thickness may be wrapped multiple times, but the predetermined thickness of the sheet material 11T can also be increased to approximately 10 mm.

[0033] Next, as shown in Fig. 7, the molded product in which the sheet material 11T is laminated on the outer peripheral surface of the cylindrical hose body 3 is placed inside a vulcanizer 14 and steam vulcanized. Through this vulcanization process, the hose body 3 is vulcanized and the sheet material 11T is hardened to form the urethane inner peripheral layer 11, as shown in Fig. 8.

[0034] Next, as shown in FIG. 9, liquid material 12T, which is a rubber composition containing a castable urethane polymer, is supplied from container 15 and applied to the outer surface of the formed inner urethane layer 11, and then allowed to mature at room temperature. The thickness of the liquid material 12T applied is adjusted depending on the thickness of the outer urethane layer 12 to be formed. If the outer urethane layer 12 is thick, the liquid material 12T is applied to a predetermined thickness repeatedly until the outer urethane layer 12 reaches the desired thickness. The maximum thickness that can be achieved by applying liquid material 12T in one application is approximately 1.0 mm.

[0035] After a predetermined maturation time has passed, the liquid material 12T hardens to form the outer urethane layer 12. As a result, the urethane layer 10 having a laminated structure in which the inner urethane layer 11 and the outer urethane layer 12 are laminated coaxially in order is formed on the outer circumferential surface of the vulcanized hose body 3 (cover layer 9), completing the marine hose 1 illustrated in Figures 1 to 4.

[0036] According to this marine hose 1, the urethane inner peripheral layer 11 can be formed by laminating and steam vulcanizing sheet-like materials 11T made of a rubber composition containing a millable urethane polymer. The time required to laminate sheet-like materials 11T of a predetermined thickness can be approximately 5 to 10 minutes for one marine hose 1. The time required to vulcanize sheet-like materials 11T is not an additional time because it is performed simultaneously with the vulcanization of other materials.

[0037] On the other hand, when forming the urethane layer 10 using a rubber composition containing a castable urethane polymer, it takes a long time to apply and mature the liquid material 12T. For example, forming a 1.0 mm thick urethane layer 10 on a single marine hose 1 takes about an hour. Furthermore, applying the liquid material 12T to a uniform thickness requires a high level of skill on the part of the worker. Therefore, using a rubber composition containing a millable urethane polymer is advantageous for obtaining a urethane layer 10 (urethane inner layer 11) of any desired thickness in a short period of time.

[0038] Furthermore, the urethane outer layer 12 can be formed by applying and aging a liquid material 12T made of a rubber composition containing a castable urethane polymer, ensuring excellent abrasion resistance. When the urethane layer 10 is formed using a rubber composition containing a millable urethane polymer, there is a risk that the abrasion resistance of the urethane layer 10 will decrease because the urethane will be hydrolyzed by steam vulcanization, but this risk can be avoided with the urethane outer layer 12 formed using the liquid material 12T.

[0039] Therefore, by forming urethane layer 10 into a laminate structure of outer urethane layer 12 and inner urethane layer 11, it becomes easier to achieve the desired thickness of urethane layer 10, and excellent abrasion resistance can be obtained on the outer peripheral surface of urethane layer 10. This is therefore advantageous for efficiently manufacturing a marine hose 1 that has good abrasion resistance and is provided with a urethane layer 10 of the desired thickness on its outermost surface.

[0040] If the thickness of the urethane outer layer 12 is 1.0 mm or less, the liquid material 12T can be applied in a single step to form the urethane outer layer 12. This is advantageous for shortening the molding time and improving productivity. To shorten the molding time, it is more preferable that the thickness of the urethane outer layer 12 be 1 mm or less.

[0041] When the outer urethane layer 12 is completely worn in the thickness direction, the inner urethane layer 11 is exposed. Therefore, if the color of the outer urethane layer 12 is different from the color of the inner urethane layer 11 laminated adjacent to the outer urethane layer 12, it becomes easy to grasp the degree of wear of the urethane layer 10 at a glance.

[0042] 5, when inner urethane layer 11 has a laminated structure in which multiple layers 11a and 11b of different colors are stacked, inner urethane layer 11b on the inner side becomes exposed when inner urethane layer 11a on the outer side is completely worn in the thickness direction. Therefore, when inner urethane layer 11 has a laminated structure in which multiple layers 11a and 11b of different colors are stacked, it becomes easier to grasp the degree of wear of urethane layer 10. [Example]

[0043] Two types of marine hoses were manufactured, each with an outer diameter of 830 mm and a 4.5 mm thick urethane layer covering the entire length of the outer surface of the hose body. In one marine hose (Example), the urethane layer had a laminated structure, as shown in FIG. 4, consisting of an outer urethane layer (1.5 mm thick) made of a rubber composition containing a castable urethane polymer, and an inner urethane layer (3 mm thick) made of a rubber composition containing a millable urethane polymer, positioned on the inner side of the outer urethane layer. In the other marine hose (Comparative Example), the urethane layer had a single-layer structure made of a rubber composition containing a castable urethane polymer. Comparing the time required from molding the urethane layer to completing the manufacture of the marine hose 1, the time required for the Example was approximately 30% of that for the Comparative Example. [Explanation of symbols]

[0044] 1 Marine hose 1a Flow path 2 Connecting end 2a flange 2b nipple 2c Retaining ring 3 Hose body 4 Inner layer 5 Inner first reinforcement layer group 5w nipple wire 6 Inner second reinforcement layer group 6r Reinforced Wire Layer 6w nipple wire 7 Outer reinforcement layer group 7w nipple wire 8 Buoyancy layer 9 Cover Layer 10 Urethane layer 11, 11a, 11b Inner urethane layer 11T Sheet material 12 Peripheral urethane layer 12T Liquid Material 13 Mandrel 14 Vulcanizing can 15 Container L fluid

Claims

1. A marine hose having a urethane layer on the outermost surface, The marine hose has a laminated structure in which the urethane layer is made of an outer urethane layer made of a rubber composition containing a castable urethane polymer (excluding rubber compositions containing a millable urethane polymer), and an inner urethane layer made of a rubber composition containing a millable urethane polymer (excluding rubber compositions containing a castable urethane polymer) placed on the inner side of the outer urethane layer.

2. 2. The marine hose according to claim 1, wherein the color of the outer urethane layer is different from the color of the inner urethane layer laminated adjacent to the outer urethane layer.

3. 3. The marine hose according to claim 1, wherein the inner circumferential urethane layer has a laminated structure in which a plurality of layers of different colors are laminated.

4. 4. The marine hose according to claim 1, wherein the urethane layer is laminated on the outer peripheral surface of a rubber layer containing NBR rubber as a main component.

5. 5. The marine hose according to claim 1, wherein the outer urethane layer has a thickness of 1 mm or less.

6. A method for manufacturing a marine hose having a urethane layer on its outermost surface, comprising: A method for manufacturing a marine hose, comprising: molding a cylindrical hose body having a cylindrical reinforcing layer embedded between a cylindrical unvulcanized inner layer and a cover layer; laminating a sheet-like material made of a rubber composition containing a millable urethane polymer on the outer surface of the hose body; placing the molded body inside a vulcanizing can and vulcanizing it with steam; forming the sheet-like material into a urethane inner layer; applying a liquid material made of a rubber composition containing a castable urethane polymer to the outer surface of the urethane inner layer and maturing it to form the liquid material into a urethane outer layer; and providing the urethane layer in a laminated structure in which the urethane inner layer and the urethane outer layer are laminated in order on the outer surface of the vulcanized hose body.

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