Method for determining specifications of fiber-reinforced material for ship hose and method for manufacturing ship hose

Abstract

The present invention provides a method for determining the specification of a fiber reinforced material having excellent fatigue resistance and capable of properly maintaining the expansion characteristics of a ship hose while ensuring sufficient pressure resistance, and a method for manufacturing a ship hose. The fiber cord (10) of the fiber reinforced material (9) constituting the cord fabric weaving structure is made into a specification in which three or four polyester filaments (10a) are twisted together, the twist coefficient K of the fiber cord (10) is set to 1900 or more and 2900 or less, the correlation R between the specified elongation E2 of a plurality of fiber cords (10) of different specifications and the hose elongation E1 of each ship hose (1) in a specified expansion test in which a fiber reinforced material (9) having each fiber cord (10) as a component is buried as a reinforcement layer (4A, 6A) is known in advance, and a threshold value Th of the specified elongation E2 is set based on the specification value of the hose elongation E1 in the specified expansion test and the correlation R, so that the specified elongation E2 of the fiber cord (10) used as the reinforcement layer (4A, 6A) is less than the threshold value Th.

Description

Technical Field

[0001] The present invention relates to a method for determining the specifications of a fiber-reinforced material for a ship hose and a method for manufacturing a ship hose. More specifically, the present invention relates to a method for determining the specifications of a fiber-reinforced material for a ship hose and having excellent fatigue resistance, which can appropriately maintain the expansion characteristics of the ship hose while ensuring sufficient pressure resistance and a method for manufacturing a ship hose. Background Art

[0002] A plurality of reinforcing layers are embedded in the ship hose. For example, these reinforcing layers use a fiber-reinforced material formed by weaving fiber cords into a cord cloth (for example, see paragraph 0011 of Patent Document 1 and paragraph 0023 of Patent Document 2). These reinforcing layers resist the internal pressure applied to the ship hose by the fluid flowing in the flow path to suppress excessive expansion of the hose body, while ensuring a predetermined pressure resistance.

[0003] As a certification test for ship hoses, after a specified number of bending tests, a destructive test is performed to destroy the hose by applying internal pressure. In this bending test, since the fiber cords constituting the fiber reinforcement material are repeatedly bent and fatigued, if the fatigue resistance of the fiber cords is poor, it is difficult to ensure the specified pressure resistance required for the ship hose. In order to improve the fatigue resistance of the fiber cords, it is effective to increase the number of twists of the fiber cords. However, as the number of twists of the fiber cords increases, it is not conducive to suppressing the elongation of the ship hose that is subjected to internal pressure. As a result, it is difficult to meet the expansion characteristics (specification value of hose elongation) required in the specified expansion test for the ship hose.

[0004] A method has been proposed in which a twisted yarn consisting of two polyester filaments is used as a fiber cord, with a primary twist coefficient of about 1000 to 2500 and a secondary twist coefficient of about 1500 to 3600 (see the claims and paragraphs 0066 to 0069 of Patent Document 3). However, since it is difficult to obtain sufficient cord breaking strength if the fiber cord is such a fiber cord formed by twisting two polyester filaments, more reinforcement layers need to be buried in order to ensure the prescribed pressure resistance in a ship hose in which a reinforcement layer using the fiber cord is buried. Therefore, in order to obtain a fiber reinforced material with excellent fatigue resistance that can ensure sufficient pressure resistance while appropriately maintaining the expansion characteristics of the ship hose, further improvement is required.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 10-157016

[0008] Patent Document 2: Japanese Patent Application Publication No. 2021-148193

[0009] Patent Document 3: Japanese Patent Application Publication No. 2017-150105 Summary of the invention

[0010] Problems to be solved by the invention

[0011] An object of the present invention is to provide a method for determining specifications of a fiber-reinforced material for a ship hose and having excellent fatigue resistance, which can appropriately maintain the expansion characteristics of the ship hose while ensuring sufficient pressure resistance, and a method for manufacturing the ship hose.

[0012] Technical means of solving problems

[0013] In order to achieve the above object, a method for determining the specification of a fiber-reinforced material for a ship hose of the present invention is a method for determining the specification of a fiber-reinforced material having a cord fabric woven structure having a plurality of fiber cords arranged side by side and a cross cord that crosses the fiber cords in a sewn manner and is used as a reinforcing layer of a ship hose, characterized in that the fiber cords are twisted together by three or four polyester filaments, the twist factor K of the fiber cords calculated by the following formula (1) is set to 1900 or more and 2900 or less, the correlation between the specified elongation of a plurality of fiber cords of different specifications and the hose elongation in a specified expansion test of each of the ship hoses in which the fiber-reinforced material having each fiber cord as a constituent member is buried as the reinforcing layer is known in advance, and a threshold value of the specified elongation in the specified expansion test required for the ship hose is set based on the specification value of the hose elongation in the specified expansion test and the correlation so that the specified elongation of the fiber cords used as the reinforcing layer is set to be less than the threshold value.

[0014] Twist coefficient K = T × D 1 / 2 · · · (1)

[0015] Wherein, T is the number of twists of the fiber cord (times / 10cm), and D is the total fineness of the fiber cord (dtex).

[0016] The method for manufacturing a ship hose of the present invention is characterized in that the fiber reinforcement material having the specifications determined by the fiber reinforcement material specification determination method is embedded as the reinforcement layer between the inner surface layer and the cover layer, an unvulcanized hose molded body is formed, and the hose molded body is vulcanized.

[0017] Effects of the Invention

[0018] According to the method for determining the specification of the fiber reinforced material for a ship hose of the present invention, by making the fiber cords of the fiber reinforced material constituting the cord fabric weaving structure a specification in which three or four polyester filaments are twisted together, and setting the twist coefficient K of the fiber cords to be 1900 or more and 2900 or less, it is advantageous to improve the fatigue resistance of the fiber cords and ensure sufficient pressure resistance of the ship hose. Furthermore, based on the specification value of the hose elongation and the correlation, the threshold value of the specified elongation is set so that the specified elongation of the fiber cord used as the reinforcement layer is less than the threshold value. As a result, in the ship hose in which the fiber reinforced material having the fiber cord as a component is buried as the reinforcement layer, it is advantageous to prevent the elongation of the hose body from becoming excessive when subjected to internal pressure and to appropriately maintain the expansion characteristics of the ship hose. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is an explanatory diagram showing an example of a ship hose manufactured according to the present invention.

[0020] Figure 2 Yes Figure 1 An explanatory diagram showing a partially enlarged longitudinal section of a ship hose.

[0021] Figure 3 So Figure 2 The AA cross-sectional view of FIG. 1 shows an example of a cross-sectional structure of a hose for a ship.

[0022] Figure 4 Yes Figure 1 An explanatory diagram showing a portion of a marine hose cut away to illustrate a reinforcement layer.

[0023] Figure 5 is to be used as Figure 4 An explanatory diagram showing an example of a fiber-reinforced material for a ship hose used as a reinforcement layer laid flat and viewed from above.

[0024] Figure 6 This is an example from a side view. Figure 5 An illustration of a fiber cord.

[0025] Figure 7 The cross-sectional view is schematically shown as an example. Figure 6 An illustration of a fiber cord.

[0026] Figure 8 This is a graph showing, by way of example, the correlation between the elongation of a fiber cord of a fiber reinforcement material embedded as a reinforcement layer in a marine hose and the hose elongation in a predetermined expansion test of the marine hose in which the fiber reinforcement material is embedded as a reinforcement layer.

[0027] Fig. 9 This is an explanatory diagram showing a part of an unvulcanized hose molded body cut out and illustrated as an example.

[0028] Fig.10 This is an example Fig. 9 An explanatory diagram of the vulcanization process of the hose forming body. DETAILED DESCRIPTION

[0029] Hereinafter, a method for determining specifications of a fiber-reinforced material for a ship hose and a method for producing a ship hose according to the present invention will be described based on the embodiments shown in the drawings.

[0030] Figures 1 to 4 The ship hose 1 shown in the example is provided with connecting metal fittings 2 for connecting other ship hoses 1 at both ends in the longitudinal direction of its cylindrical hose body 1A. The connecting metal fitting 2 includes a pipe joint 2b extending in the longitudinal direction of the ship hose 1 and a flange 2a joined to one end in the longitudinal direction of the pipe joint 2b. Generally, eight to ten ship hoses 1 are connected and used.

[0031] like Figure 2 , Figure 3 As shown in the example, the hose body 1A extending between the pipe joints 2b at both ends is constructed as follows: the inner surface layer 3, the inner peripheral side reinforcement layer group 4, the main body layer 5, the outer peripheral side reinforcement layer group 6, the buoyancy layer 7, and the cover layer 8 are stacked in order from the inner peripheral side to the outer peripheral side of the hose body 1A on the outer peripheral side of the flow path 1b. The single-point chain line CL in the figure is the center line that passes through the cross-sectional center of the ship hose 1 and extends in the longitudinal direction of the hose. Although Figure 3 The description is for a 1 / 4 range of the cross-section of the ship hose 1 , but the other range (3 / 4 range) not described also has the same structure.

[0032] The inner peripheral side of the inner surface layer 3 is the flow path 1b of the fluid L. As the fluid L, crude oil, gasoline, LPG (Liquefied Petroleum Gas: liquefied petroleum gas) etc. can be exemplified. The inner surface layer 3 selects a suitable material according to the type of the fluid L. If the fluid L is crude oil etc., it is composed of nitrile rubber etc. with excellent oil resistance.

[0033] In the present embodiment, two inner circumferential reinforcement layer groups 4 are stacked, but there is also a case where the inner circumferential reinforcement layer group 4 is one. The inner circumferential reinforcement layer group 4 and the outer circumferential reinforcement layer group 6 are respectively formed by stacking a plurality of reinforcement layers 4A and 6A. The number of reinforcement layers 4A and 6A is set to be appropriate and necessary. For example, the number of reinforcement layers 4A is about 4 to 30 layers, and the number of reinforcement layers 6A is about 2 to 10 layers.

[0034] like Figure 4As shown in the example, each reinforcement layer 4A, 6A is formed into a cord fabric weaving structure in which the crossing cords 11 that cross the plurality of fiber cords 10 that are parallel and parallel in a vertical sewing manner are separated and arranged in the longitudinal direction of the fiber cords 10. In each reinforcement layer 4A, 6A, the plurality of fiber cords 10 extend at a predetermined angle relative to the center line CL. In the reinforcement layers 4A and 6A stacked adjacent to each other, the inclination directions of the fiber cords 10 are arranged to be opposite to each other and cross each other. The details of the reinforcement layers 4A and 6A will be described later.

[0035] The main body wire layer 5 is formed by spirally winding metal wires at predetermined intervals on the outer peripheral rubber of the inner peripheral side reinforcement layer group 4. The inner peripheral side reinforcement layer group 4, the main body wire layer 5, and the outer peripheral side reinforcement layer group 6 are fixed to the pipe joint 2b by the pipe joint wires 4w, 5w, 6w at one end of each and the fixing ring 2c protruding from the outer peripheral surface of the pipe joint 2b. Between the inner peripheral side reinforcement layer group 4 and the outer peripheral side reinforcement layer group 6 is a space (fluid retention layer) for storing the fluid L when the fluid L leaks from the flow path 1b.

[0036] The buoyancy layer 7 is made of a material such as sponge rubber or foamed polyurethane that exerts buoyancy to make the ship hose 1 float on the sea. Therefore, the ship hose 1 is a so-called floating type. If the ship hose 1 is a submarine type used in a state of sinking in the sea, the buoyancy layer 7 is omitted.

[0037] The cover layer 8 is made of a water-impermeable material such as rubber, and has a line pattern or the like with excellent visual visibility on its surface. The cover layer 8 is made of an appropriate material having excellent weather resistance and external damage resistance.

[0038] Figure 5 The fiber reinforcement material 9 for a ship hose (hereinafter referred to as the fiber reinforcement material 9) shown as an example is embedded in the hose body 1A as each reinforcement layer 4A, 6A. The fiber reinforcement material 9 has a cord fabric weaving structure composed of a plurality of fiber cords 10 arranged in parallel in the width direction W and extending in the length direction L, and a cross cord 11 that crosses these fiber cords 10 in a vertically sewn manner and extends in the width direction W.

[0039] The specification of the fiber-reinforced material 9 is determined by the specification determination method of the present invention.

[0040] The fiber reinforcement material 9 adopts a cord fabric weaving structure. If the cord fabric weaving structure is adopted, the interference between the fiber cords 10 and the cross cords 11 will be reduced, which is conducive to improving the durability of the fiber reinforcement material 9 (reinforcement layer 4A, 6A). The weaving density of the fiber cords 10 is set to, for example, 30 or more and 70 or less / 5cm, and the weaving density of the cross cords 11 is set to, for example, 2 or more and 8 or less / 5cm. The interval (gap) between adjacent fiber cords 10 is set to, for example, 0.13 mm or more and 0.25 mm or less, and more preferably 0.2 mm or more and 0.24 mm or less.

[0041] The fiber cord 10 is formed by twisting three or four polyester filaments 10 a together. Figure 6 , Figure 7 The fiber cord 10 shown in the example is formed by twisting three filaments 10a, but may be formed by twisting four filaments 10a. The fiber cord 10 is formed by twisting the filaments 10a preliminarily twisted in one direction in a direction opposite to the preliminarily twisted direction.

[0042] Forming the fiber cord 10 by twisting 3 or 4 filaments 10a made of polyester is conducive to improving the strength at break (cord breaking strength) without damaging the fatigue resistance of the fiber cord 10. If the fiber cord is a fiber cord 10 formed by twisting 2 filaments 10a, it is difficult to improve the cord breaking strength. If the filaments 10a are thickened to increase the cord breaking strength, the weight will increase, resulting in excessive weight increase when using 1 ship hose. In addition, the thickness of the fiber cord 10 (reinforcement layer 4A, 6A) will increase, resulting in a thicker diameter of the ship hose 1. In addition, if the fiber cord is a fiber cord 10 formed by twisting more than 5 filaments 10a, the outer diameter of the cord is too large, resulting in easy damage to fatigue resistance. In order to achieve lightweight fiber cord 10 and improve fatigue resistance, it is preferred to twist 3 filaments instead of 4 filaments 10a.

[0043] Furthermore, the initial breaking strength of the fiber cord 10 is preferably 300 N / cord or more, more preferably 320 N / cord or more. This initial breaking strength is advantageous for stably ensuring the pressure resistance of the marine hose 1.

[0044] The outer diameter of the fiber cord 10 is set to be, for example, not less than 0.80 mm and not more than 0.95 mm. If the outer diameter is less than 0.80 mm, it is difficult to ensure the cord breaking strength of the fiber cord 10, resulting in a disadvantage in improving the pressure resistance of the ship hose 1. On the other hand, if the outer diameter exceeds 0.95 mm, it is disadvantageous in reducing the weight of the fiber cord 10, and the weight increase is too large when used for one ship hose. In addition, the thickness of the fiber cord 10 (reinforcement layers 4A, 6A) increases, resulting in a larger diameter of the ship hose 1.

[0045] In the fiber-reinforced material 9, the twist coefficient K of the fiber cord 10 calculated by the following formula (1) is set to 1900 or more and 2900 or less.

[0046] Twist coefficient K = T × D 1 / 2 · · · (1)

[0047] Wherein, T is the number of twists of the fiber cord (times / 10cm), and D is the total fineness of the fiber cord (dtex).

[0048] If the twist coefficient K of the fiber cord 10 is less than 1900, it is not advantageous to ensure the fatigue resistance of the fiber cord 10. On the other hand, if the twist coefficient K exceeds 2900, the cord breaking strength of the fiber cord 10 is significantly reduced. Therefore, in order to avoid a decrease in the cord breaking strength while ensuring the fatigue resistance of the fiber cord 10, the twist coefficient K is preferably set to 1900 to 2900, and more preferably 1950 to 2600. By setting the twist coefficient K within such a range, it is advantageous to stably ensure sufficient pressure resistance of the ship hose 1. In addition, there is no need to stack too many reinforcing layers 4A and 6A in order to ensure sufficient pressure resistance of the ship hose 1.

[0049] The ship hose 1 is required to have a hose elongation E1 in a predetermined expansion test that is equal to or less than a standard value. The specific method of the predetermined expansion test is as follows.

[0050] First, an internal pressure of 0.7 bar was applied to the ship hose 1 and the hose length (initial hose length) was measured. Next, the internal pressure was increased from 0.7 bar to half of the rated pressure over 5 minutes and maintained for 10 minutes. Then, after the internal pressure was reduced to 0, the pressure was increased to the rated pressure over 5 minutes and maintained for 10 minutes, and the hose length in the maintained state (rated pressure hose length) was measured.

[0051] The hose elongation E1 is calculated by (rated pressure hose length - initial hose length) / initial hose length × 100%. The specification value of the hose elongation E1 is 2.5% or less. If the hose elongation E1 is 2.5% or less, it is evaluated as acceptable, and if it exceeds 2.5%, it is evaluated as unacceptable.

[0052] Therefore, the manufactured ship hose 1 needs to set the hose elongation E1 in the specified expansion test to a standard value (2.5%) or less. If the elongation of the fiber cord 10 is large, the ship hose 1 in which the fiber reinforcement material 9 having the fiber cord 10 as a component is buried as the reinforcement layer 4A, 6A tends to be easily elongated when subjected to internal pressure. That is, it can be considered that the specified elongation E2 of the fiber cord 10 and the hose elongation E1 have a relatively high correlation.

[0053] Therefore, in this embodiment, data R of the correlation R between the specified elongation E2 of a plurality of fiber cords 10 of different specifications and the hose elongation E1 of each ship hose 1 in the above-mentioned specified expansion test in which the fiber reinforcement material 9 having these fiber cords 10 as components is buried as the reinforcement layer 4A, 6A is obtained in advance.

[0054] For example, a plurality of fiber cords 10 having different predetermined elongations E2 are prepared, and a test sample of the ship hose 1 is manufactured using the fiber reinforcement material 9 having each fiber cord 10 as a component. Then, the hose elongation E1 is obtained by actual measurement using each test sample of the ship hose 1. Alternatively, the hose elongation E1 may be obtained by computer simulation of a predetermined expansion test of the ship hose 1. As the predetermined elongation E2 of the fiber cord 10, for example, the degree of tensile stress acting on the fiber cord 10 when the ship hose 1 is used or the elongation under any tensile stress below the tensile stress is used.

[0055] Master e.g. Figure 8 The data of the correlation R between the hose elongation E1 and the specified elongation E2 of the fiber cord 10 as shown in FIG. When determining the specification of the fiber reinforcement material 9, the threshold value Th of the specified elongation E2 of the fiber cord 10 used is set based on the specification value (2.5%) of the hose elongation E1 and the obtained correlation R. Then, the specified elongation E2 of the fiber cord 10 of the fiber reinforcement material 9 used as the reinforcing layer 4A, 6A of the ship hose 1 is set to be less than the set threshold value Th.

[0056] In the ship hose 1 in which the fiber reinforcement material 9 having the fiber cords 10 having the predetermined elongation E2 being equal to or less than the threshold value Th is embedded as the reinforcing layers 4A and 6A, the hose elongation E1 in the above-mentioned predetermined expansion test can be set more accurately to a standard value (2.5%) or less. That is, in the ship hose 1, it is advantageous to prevent the hose body 1A from elongating too much when subjected to internal pressure and to appropriately maintain the expansion characteristics of the ship hose 1.

[0057] The inventors of the present application confirmed and analyzed the correlation between the elongation of the fiber cord 10 under various tensile stresses as the predetermined elongation E2 and the hose elongation E1. As a result, it was found that the elongation E2 of the fiber cord 10 at 1.3 cN / dtex and the hose elongation E1 have a very high correlation.

[0058] Therefore, when determining the specification of the fiber reinforcement material 9, it is sufficient to obtain data of the correlation R between the hose elongation E1 in the above-mentioned prescribed expansion test and the elongation E2 of the fiber cord 10 buried in the ship hose 1 at 1.3 cN / dtex. Then, it is preferable to set a threshold value Th of the prescribed elongation E2 of the fiber cord 10 based on the specification value (2.5%) of the hose elongation E1 and the obtained correlation R. By using the fiber cord 10 whose prescribed elongation E2 is equal to or less than the threshold value Th, the hose elongation E1 in the above-mentioned prescribed expansion test can be set to be equal to or less than the specification value (2.5%) with higher accuracy.

[0059] When using the correlation R, by setting the elongation E2 of the fiber cord 10 at 1.3 cN / dtex to 6.5% or less, the hose elongation E1 of the ship hose 1 of various specifications can be set to be substantially less than the specification value (2.5%). Therefore, if the threshold value Th is simply set, the elongation E2 (6.5%) of the fiber cord 10 at 1.3 cN / dtex can be set as the threshold value Th.

[0060] That is, the elongation E2 of the fiber cord 10 used in the fiber reinforcement material 9 embedded as the reinforcing layer 4A, 6A at 1.3 cN / dtex may be 6.5% or less. In order to suppress the hose elongation E1, the elongation E2 of the fiber cord 10 at 1.3 cN / dtex is preferably 5.5% or less, and more preferably 5.0% or less. The lower limit of the elongation of the fiber cord 10 at 1.3 cN / dtex is, for example, 3%.

[0061] The specified elongation E2 of the fiber cord 10 (elongation E2 at 1.3 cN / dtex, etc.) can be adjusted to a desired range by a known method. For example, at least one of the heating temperature, the tension, and the speed (time) of the heat treatment of the fiber cord 10 can be adjusted by a known method, or by using a corresponding appropriate polyester raw yarn, etc., to adjust the specified elongation E2 to a desired range.

[0062] In the fiber-reinforced material 9 (reinforcement layers 4A, 6A), the cross cords 11 have little effect on the performance and characteristics of the fiber cords 10 , and thus any known specifications may be adopted.

[0063] The predetermined elongation E2 and the strength at break (cord breaking strength) of the fiber cord 10 are values ​​measured in accordance with JIS L1017: 2002. The cord breaking strength of the fiber cord 10 slightly changes before and after vulcanization, but can be considered to be substantially the same.

[0064] In order to manufacture the ship hose 1, a known method can be used. The connecting metal member 2 is externally fitted on the cylindrical mandrel 13, and the connecting metal member 2 is sequentially stacked on the outer circumference of the mandrel 13. Figure 2 The components of the hose body 1A shown as an example (inner surface layer 3, inner peripheral reinforcement layer group 4, main body layer 5, outer peripheral reinforcement layer group 6, buoyancy layer 7, cover layer 8) are made into a state covered with a known adhesive rubber and buried between the inner surface layer 3 and the cover layer 8 as reinforcement layers 4A and 6A. Fig. 9 A hose shaped body 12 is shown by way of example.

[0065] Then, if Fig.10 As shown in the example, the hose molded body 12 is placed in a known vulcanizing device 14 for vulcanization. In this vulcanization step, the unvulcanized rubber or adhesive rubber contained in the components of the hose molded body 12 is vulcanized, and the stacked components are joined together to manufacture the ship hose 1.

[0066] As described above, in the present invention, the fiber reinforcement material 9 is made into a cord fabric weave structure in which a plurality of fiber cords 10 formed by twisting three or four polyester filaments 10a are arranged side by side, and the twist coefficient K of the fiber cord 10 is set to 1900 or more and 2900 or less, and the prescribed elongation E2 of the fiber cord 10 is set to be less than the threshold value Th. By meeting these requirements simultaneously, the fatigue resistance of the fiber cord 10 can be improved while the elongation can be appropriately suppressed, thereby obtaining sufficient cord breaking strength. Since there is a synergistic effect caused by meeting these requirements simultaneously, in the ship hose 1 in which the fiber reinforcement material 9 is buried as the reinforcement layer 4A, 6A, it is very advantageous to avoid excessive elongation of the hose body 1A when subjected to internal pressure, appropriately maintain the expansion characteristics of the ship hose 1, and ensure sufficient pressure resistance.

[0067] Example

[0068] The specifications of the fiber cords formed by twisting filaments made of polyester were changed as shown in Table 1, and a total of 12 types were produced, including the conventional example, Examples 1 to 6, and Comparative Examples 1 to 5. The twist coefficient K in Table 1 is a value calculated by the above formula (1). In Table 1, Comparative Examples 4 and 5, in which the intervals between the fiber cords are negative values, mean that the adjacent fiber cords are arranged side by side and interfere with each other. The following tensile test and fatigue test were performed on the fiber cords of each specification.

[0069] [Tensile test of fiber cord]

[0070] The breaking strength of each fiber cord was measured in accordance with JIS L1017:2002, and the elongation E2 at 1.3 cN / dtex was calculated from the measured data. The results are shown in Table 1.

[0071] [Fatigue test of fiber cord]

[0072] According to the disc brake fatigue strength (Goodrich method) specified in JIS L1017:2002 Annex 1 2.2.2, the rubber test piece with each fiber cord embedded is rotated at a speed of 1400 rpm at room temperature, and a strain of ±15% is applied 2 million times within 24 hours. The breaking strength of the fiber cord taken out of the rubber test piece before the fatigue test (initial cord breaking strength) and the breaking strength of the fiber cord taken out of the rubber test piece after the fatigue test (cord breaking strength after fatigue test) are measured. Then, the cord breaking strength retention rate is calculated = (cord breaking strength after fatigue test / initial cord breaking strength) × 100%.

[0073] The standard value of the initial breaking strength of the cord is 300 N / cord. If it is equal to or greater than this standard value, it is evaluated as having sufficient strength, and if it is less than this standard value, it is evaluated as insufficient in strength.

[0074] The standard value of the cord breaking strength retention rate is 75%. If it is equal to or higher than this standard value, it is evaluated that the fatigue resistance is sufficient, and if it is less than this standard value, it is evaluated that the fatigue resistance is insufficient.

[0075] In addition, using each fiber cord, a different fiber cord is produced. Figure 5 The fiber-reinforced layer of 12 types of cord fabric weaving structures (weaving density of fiber cords is 48 cords / 5 cm, weaving density of cross cords is 4 cords / cm) is shown as an example. The cross cords are cotton fibers, and the cord outer diameter is 0.30 mm.

[0076] Each fiber-reinforced material is buried as a reinforcement layer, and samples of ship hoses with only different reinforcement layers are produced, and the expansion test of the ship hose specified above is performed. Each sample of the ship hose has a structure in which two inner circumferential reinforcement layer groups, a main body line layer, an outer circumferential reinforcement layer group, a buoyancy layer, and a covering layer are sequentially stacked on the inner surface layer. The number of reinforcement layers constituting each inner circumferential reinforcement layer group is 10, and the number of reinforcement layers constituting the outer circumferential reinforcement layer group is 8. The hose elongation E1 during the expansion test is measured. The results are shown in Table 1. The specification value of the hose elongation E1 is 2.5%. If it is below this specification value, the expansion characteristics of the ship hose are evaluated to be appropriate. If it exceeds this specification value, the expansion characteristics of the ship hose are evaluated to be inappropriate.

[0077] [Table 1]

[0078]

[0079] As can be seen from the results in Table 1, the initial cord breaking strength, cord breaking strength retention rate, and hose elongation E1 of the fiber cords all satisfy the standard values ​​(specification values) in Examples 1 to 6. Therefore, it can be seen that the fiber cords corresponding to Examples 1 to 6 are excellent in fatigue resistance, and in the ship hoses corresponding to Examples 1 to 6, sufficient pressure resistance can be ensured while appropriately maintaining the expansion characteristics.

[0080] Description of Reference Numerals

[0081] 1: Marine hose

[0082] 1A: Hose body

[0083] 1b: Flow path

[0084] 2: Connecting metal parts

[0085] 2a: Flange

[0086] 2b: Pipe joint

[0087] 2c: Fixed ring

[0088] 3: Inner surface layer

[0089] 4: Inner reinforcement layer

[0090] 4A: Enhancement layer

[0091] 4w: pipe joint line

[0092] 5: Body line layer

[0093] 5w: pipe joint line

[0094] 6: Outer peripheral reinforcement layer

[0095] 6A: Enhancement layer

[0096] 6w: pipe joint line

[0097] 7: Buoyancy layer

[0098] 8: Overlay

[0099] 9: Fiber-reinforced materials

[0100] 10: Fiber cord

[0101] 10a: Filament

[0102] 11: Crossing the cord

[0103] 12: Hose forming body

[0104] 13: Mandrel

[0105] 14: Vulcanization device

[0106] L: Fluid

Claims

1. A method for determining the specification of a fiber-reinforced material, the method comprising: a fiber-reinforced material having a cord fabric woven structure having a plurality of fiber cords arranged side by side and cross cords that cross the fiber cords in a sewn manner and used as a reinforcing layer of a marine hose, wherein: The fiber cord is made into a specification in which three or four polyester filaments are twisted together, the twist coefficient K of the fiber cord calculated by the following formula (1) is set to 1900 or more and 2900 or less, the correlation between the specified elongation of a plurality of fiber cords of different specifications and the hose elongation in a specified expansion test of each of the ship hoses in which the fiber reinforcement material having each fiber cord as a constituent member is buried as the reinforcement layer is known in advance, and a threshold value of the specified elongation in the specified expansion test required for the ship hose is set based on the specification value of the hose elongation in the specified expansion test and the correlation, so that the specified elongation of the fiber cord used as the reinforcement layer is set to be less than the threshold value, Twist coefficient K = T × D 1 / 2 ··· (1) Wherein, T is the number of twists of the fiber cord (times / 10cm), and D is the total fineness of the fiber cord (dtex).

2. The method for determining the specification of a fiber-reinforced material according to claim 1, wherein: The elongation of the fiber cord at 1.3 cN / dtex is set to the predetermined elongation.

3. The method for determining the specification of a fiber-reinforced material according to claim 2, wherein: The threshold value is set to be 6.5% of the elongation of the fiber cord at 1.3 cN / dtex.

4. The method for determining the specification of a fiber-reinforced material according to any one of claims 1 to 3, wherein: The twist coefficient K is set to 1950 or more and 2600 or less, and the breaking strength of the fiber cord is set to 300N or more.

5. The method for determining the specification of a fiber-reinforced material according to any one of claims 1 to 3, wherein: The fiber cord was made into a specification in which three polyester filaments were twisted together.

6. The method for determining the specification of a fiber-reinforced material according to any one of claims 1 to 3, wherein: The outer diameter of the fiber cord is set to be 0.80 mm or more and 0.95 mm or less.

7. A method for manufacturing a hose for a ship, wherein: The fiber-reinforced material having the specification determined by the fiber-reinforced material specification determination method according to any one of claims 1 to 6 is embedded as the reinforcement layer between the inner surface layer and the cover layer to form an unvulcanized hose molded body, and the hose molded body is vulcanized.

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