tank

Abstract

A tank comprising: a liner that is an inner shell; and a reinforcing layer that covers the outer surface of the liner, wherein the reinforcing layer is formed by continuously winding resin impregnated fiber bundles around the liner and comprises a hoop layer and a helical layer arranged on the liner side, a gap is generated between the adjacent resin impregnated fiber bundles wound on the hoop layer, there is at least one place where the adjacent resin impregnated fiber bundles are wound without any gaps in the helical layer, and the toughness value of a resin constituting the tank is equal to or higher than 1.0 MPa·m0.5.　The present invention provides: an inexpensive tank which doses not require the accurate arrangement of resin impregnated fiber bundles, a device for detecting a gap between the resin impregnated fiber bundles, etc.; and a method for manufacturing the tank.

Description

[Technical field]

[0001] The present invention relates to a tank made of fiber reinforced plastic (FRP). [Background technology]

[0002] FRP is a composite material made of resin reinforced with reinforcing fibers, and is widely used because it is lighter than metal materials such as steel and aluminum, yet exhibits strength and rigidity equal to or greater than those of metal materials.

[0003] FRP can be molded into various shapes, such as flat plates, H-shapes, and cylindrical bodies. Of these, tanks used to store high-pressure gas or liquid are generally manufactured by filament winding molding. The filament winding molding method is a molding method in which a fiber bundle wound around a bobbin is continuously unwound while applying tension, and after impregnating it with a curable resin, the fiber bundle is wound around a liner to form a reinforcing layer.

[0004] In tanks made using the filament winding method, gaps between fiber bundles during molding can cause a decrease in pressure resistance. For this reason, it is common to mold adjacent fiber bundles by overlapping them to prevent gaps between the fibers. However, this method creates unevenness between the overlapping and non-overlapping fiber bundles, which causes differences in tension applied to the fiber bundles, causing sagging in the fiber bundles that are under low tension, and disrupting the alignment of the fiber bundles. As a result, the tank's pressure resistance can decrease.

[0005] For this reason, for example, Patent Document 1 proposes a method of preparing fiber bundles with different thicknesses in the width direction and overlapping the thin parts of the fiber bundles to prevent unevenness caused by overlapping the fiber bundles by devising a way to overlap the fiber bundles. Patent Document 2 proposes a method of preventing gaps from occurring between bands during molding by deforming a flat fiber bundle into a square shape. Patent Document 3 proposes a method of detecting gaps between bands during filament winding molding. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-209887 A [Patent Document 2] JP 2012-140997 A [Patent Document 3] JP 2017-7104 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in a situation where high production speed is also required, it is difficult to butt the sides of the fiber bundles together and wind them without gaps, as in Patent Document 1, or to deform a flat fiber bundle into a square shape during the process, as in Patent Document 2. Furthermore, the method of detecting gaps between fiber bundles during filament winding molding, as described in Patent Document 3, requires a detection device, which raises concerns about increased costs for the tank.

[0008] In view of the above, the present invention provides an inexpensive tank that does not require the conventional work of precisely arranging fiber bundles or devices for detecting gaps between fiber bundles. [Means for solving the problem]

[0009] In order to solve the above problems, the tank of the present invention has the following configuration. A tank having a liner as an inner shell and a reinforcing layer covering the outer surface of the liner, the reinforcing layer being formed by continuously winding a resin-impregnated fiber bundle around the liner, and the reinforcing layer being disposed on the liner side. Multiple layers of Hoop layer and Multiple layers of Helical layer and are laminated The hoop layer at least one hoop layer among To at an angle of 80° or more and 110° or less with respect to the axial direction of the liner A gap is provided between adjacent wrapped resin-impregnated fiber bundles, and adjacent resin-impregnated fiber bundles in the helical layer are at an angle greater than 0° and less than 80°, or greater than 110° and less than 180° with respect to the axial direction of the liner There is at least one portion where the resin constituting the tank is wound without any gaps. of Toughness value is 1.0MPa m 0.5 That's all. wherein the ratio of the total area exposed from the gaps provided between adjacent resin-impregnated fiber bundles wound around the hoop layer to the body surface area of the liner is greater than 0% and less than 50%, the minimum value of the gaps provided between adjacent resin-impregnated fiber bundles wound around the hoop layer is Lmin (mm), the maximum value is Lmax (mm), and the average width of the adjacent resin-impregnated fiber bundles wound around the hoop layer is W (mm), satisfying the relationship 0.01 < Lmin / W < 0.5 and 0.01 < Lmax / W < 0.5 A tank.

[0010] The tank of the present invention comprises: provided between adjacent resin-impregnated fiber bundles wound around at least one hoop layer of the hoop layer The gap 、 In contact with the liner innermost layer It is preferable that it is provided only on the hoop layer.

[0011] The tank of the present invention has a surface area of ​​the liner body that is substantially the same as that of the adjacent hoop layers. the Between the resin-impregnated fiber bundles the The ratio of the total area exposed through the gap is greater than 0% and less than 50% Yes.

[0012] The tank of the present invention is the gaps provided between adjacent resin-impregnated fiber bundles wound around the hoop layer The minimum gap value is Lmin (mm), the maximum gap value is Lmax (mm), the gaps provided between adjacent resin-impregnated fiber bundles wound around the hoop layer Adjacent to the gap the When the average width of the resin-impregnated fiber bundle is W (mm), satisfies the following relationship .

[0013] 0.01 < Lmin / W < 0.5 and 0.01 < Lmax / W < 0.5

[0014] The tank of the present invention is made of adjacent hoop layers wound around the hoop layer. the It is preferable that there is at least one location where there is no gap between the resin-impregnated fiber bundles.

[0015] In the tank of the present invention, the weight percentage of the resin contained in the reinforcing layer is preferably 21% to 30%.

[0016] The tank of the present invention is a resin impregnated fiber bundle. of The viscosity is preferably 10 to 150 Pa·s at 25°C. Effect of the Invention

[0017] The present invention makes it possible to provide an inexpensive tank that does not require the previously required work of precisely arranging resin-impregnated fiber bundles or devices for detecting gaps between resin-impregnated fiber bundles. [Brief description of the drawings]

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0019] Hereinafter, the embodiments of the present invention will be described in order. The embodiments are merely examples of implementing the present invention, and the present invention is not limited to the embodiments.

[0020] The tank 101 according to the present invention has a liner 102 as an inner shell, and a reinforcing layer 103 covering the outer surface of the liner 102. The reinforcing layer 103 is formed by continuously winding a resin-impregnated fiber bundle 403 around the liner 102, and the reinforcing layer 103 is disposed on the liner 102 side. Multiple layers of Hoop layer 201 and Multiple layers of Helical layer 203 and are laminated The hoop layer 201 at least one hoop layer among To at an angle of 80° or more and 110° or less with respect to the axial direction of the liner A gap 402 is provided between adjacent wrapped resin-impregnated fiber bundles, and adjacent resin-impregnated fiber bundles 403 are wound in the helical layer 203. at an angle greater than 0° and less than 80°, or greater than 110° and less than 180° with respect to the axial direction of the liner There is at least one place where the resin that constitutes the tank 101 is wound without any gaps. of Toughness value is 1.0MPa m 0.5 That's all. and the ratio of the total area exposed from the gaps 402 provided between adjacent resin-impregnated fiber bundles 403 wound around the hoop layer 201 to the surface area of the body portion of the liner 102 is greater than 0% and less than 50%. When the minimum value of the gap 402 provided between adjacent resin-impregnated fiber bundles wound around the hoop layer is Lmin (mm), the maximum value is Lmax (mm), and the average width of the adjacent resin-impregnated fiber bundles 403 adjacent to the gap 402 provided between adjacent resin-impregnated fiber bundles wound around the hoop layer is W (mm), the relationship 0.01 < Lmin / W < 0.5 and 0.01 < Lmax / W < 0.5 is satisfied Tank 101.

[0021] 1 shows a cross-sectional view of the tank 101. The liner 102 has a cylindrical body and a dome-shaped mirror portion connected to the openings provided at both ends of the body. The tank 101 is preferably made of aluminum, steel, resin, or the like that has gas barrier properties in order to retain the gas filled inside.

[0022] The reinforcing layer 103 is formed by continuously winding a resin-impregnated fiber bundle around the liner 102, and is capable of providing the pressure resistance of the tank 101.

[0023] The reinforcing layer 103 is composed of a hoop layer and a helical layer that are arranged on the liner 102 side. The required pressure resistance can be achieved by stacking the hoop layers and helical layers in the required number of layers and angles to the required thickness. Here, the hoop layers and the helical layers will be explained.

[0024] A schematic diagram showing an example of a hoop layer 201 is shown in Figure 2(a). The hoop layer 201 is formed by winding and stacking resin-impregnated fiber bundles 403 around the cylindrical body of the liner 102 at an angle of 80° to 110° with respect to the axial direction 204 of the liner. The molding pattern in which the resin-impregnated fiber bundles are wound from one end of the body to the other end at the stacking angle shown in Figure 2(a) to cover the entire body is called a hoop winding, and one layer is one unit of this. The required hoop layer thickness is obtained by repeating the hoop winding. The pressure resistance of the tank in the circumferential direction 202 is determined by the thickness of the stacked hoop layers 201.

[0025] Next, a schematic diagram showing an example of the helical layer 203 is shown in Figure 2 (b). The helical layer 203 is formed by winding and laminating resin-impregnated fiber bundles 403 at an angle greater than 0° and less than 80°, or greater than 110° and less than 180°, with respect to the axial direction 204 of the liner. A molding pattern that covers the entire body from the head section at the lamination angle is called helical winding, and one layer is one unit of this. The required helical layer thickness is obtained by repeating helical winding. The pressure resistance of the tank in the axial direction 204 is determined by the thickness of the laminated helical layer 203.

[0026] By combining the hoop layer 201 and the helical layer 203 in this manner, the tank 101 as shown in FIG. 3 is completed.

[0027] In the present invention, the Hoop Layer 201 at least one of Hoop layer is at an angle of 80° or more and 110° or less with respect to the axial direction of the liner A gap 402 is provided between adjacent wrapped resin-impregnated fiber bundles, and adjacent resin-impregnated fiber bundles 403 in the helical layer 203 are is at an angle greater than 0° and less than 80°, or greater than 110° and less than 180° with respect to the axial direction of the liner It is important that there is at least one point where the wrap is completely wrapped.

[0028] In order to ensure safety in the event of a rupture, the tank 101 is sometimes required to have the rupture originate from the body, as described in KHKS0121 (2016). To meet this requirement, it is common to design the thickness of the reinforcing layer 103 so that the pressure generated in the reinforcing layer 103 when filled with gas is higher in the circumferential direction 202 of the tank than in the axial direction 204 of the tank, so that the rupture originates from the body.

[0029] Therefore, if the resin-impregnated fiber bundles 403 of the hoop layer 201 are not wound uniformly, i.e., if the alignment is disturbed, the strength of the resin-impregnated fiber bundles 403 may not be fully developed, and the fiber bundles may not break at the trunk as designed. In particular, if the resin-impregnated fiber bundles 403 being wound around the liner 102 overlap, a tension difference occurs between the overlapped and non-overlapped portions of the resin-impregnated fiber bundles 403, and the resin-impregnated fiber bundles 403 with low tension loosen, causing fiber alignment to be disturbed. Therefore, it is important to provide a gap 402 between adjacent resin-impregnated fiber bundles wound around the hoop layer 201. Without such a configuration, it is not possible to eliminate the overlap of the resin-impregnated fiber bundles 403, which causes tension differences in the resin-impregnated fiber bundles 403 and makes it impossible to adjust the fiber alignment.

[0030] Furthermore, it is important that there is at least one location in the helical layer 203 where adjacent resin-impregnated fiber bundles 403 are wound without gaps. Providing gaps in the helical layer 203 serves to adjust the fiber alignment, but if there are many gaps, the connected gaps will exist as large defects, and the defects will become the starting points and reduce the pressure resistance of the tank 101. When gas is filled, the pressure acting on the helical layer 203 is lower than that of the hoop layer 201, so even if the fiber alignment of the helical layer 203 is disturbed, the tank 101 will not be destroyed, so it is important that there is at least one location in the helical layer 203 where adjacent resin-impregnated fiber bundles are wound without gaps. Without this configuration, it is not possible to prevent gaps from connecting throughout the reinforcing layer 103.

[0031] Furthermore, the toughness of the resin that constitutes the tank 101 is 1.0 MPa·m 0.5 It is important that the resin toughness is 1.4 MPa m 0.5 It is preferable that the resin toughness is 1.0 MPa m or more. 0.5 If the resin toughness is smaller than this, the gaps between the resin-impregnated fiber bundles 403 become the starting points for destruction, and the pressure resistance of the tank 101 decreases. The preferable upper limit of the resin toughness value is 3.0 MPa m 0.5 and 2.6 MPa m 0.5 When the upper limit of the resin toughness value is within the above-mentioned preferred range, the propagation of cracks that occur when pressure is applied is suppressed, and it becomes easy to ensure the pressure resistance required for the tank 101.

[0032] In the present invention, adjacent wound around at least one hoop layer of the hoop layer Between resin-impregnated fiber bundles provided in the Gap 402 the Contact with liner 102 innermost It is preferable that the gap is provided only on the hoop layer 201. The pressure generated in the tank reinforcement layer 103 during gas filling is higher on the inner layer than on the outer layer, and the layer in contact with the liner 102 is subjected to the greatest pressure. Therefore, it is preferable to arrange the hoop layer 201 on the contact surface with the liner 102, which is the starting point of destruction. In addition, the reinforcement layer on the outer layer side of the helical layer 203 installed on the hoop layer 201 provided on the innermost layer does not need to have a gap between the resin-impregnated fiber bundles 403 in both the hoop layer 201 and the helical layer 203. This is because the pressure applied to the reinforcement layer on the outer layer side is lower than that of the innermost layer, so that the impact of misalignment of the resin-impregnated fiber bundles 403 on the pressure resistance is low.

[0033] In the present invention, the ratio of the surface area of ​​the body of the liner 102, which is the inner shell, to the surface area of ​​the adjacent hoop layers 201 is the Between the resin-impregnated fiber bundles 403 the The ratio of the total area exposed through the gaps (hereinafter sometimes referred to as the "gap area between fiber bundles") is greater than 0% and less than 50%. . More preferably, the ratio is greater than 0.01% and less than 45%.range In this case, it is possible to ensure gaps in the hoop layer 201, while the gaps in the hoop layer 201 are unlikely to become major defects, and a decrease in pressure resistance can be effectively prevented.

[0034] Here, a method for measuring the gap area between the fiber bundles and the body area of ​​the liner 102, which is the inner shell, will be described with reference to FIG. 4. The liner 102 is composed of a cylindrical body inside a tangent line 401, which is the boundary line between the straight body of the tank and the curved surface, and a dome-shaped mirror part connected to the openings provided at both ends of the body. The body area of ​​the liner 102 is the area of ​​the cylindrical body inside the tangent line 401, and the area of ​​the gaps 402 between the resin-impregnated fiber bundles is the body area minus the winding area of ​​the resin-impregnated fiber bundles 403. These areas can be measured by temporarily stopping the filament winding molding machine when the resin-impregnated fiber bundles 403 are being wound around the liner 102. After acquiring an external image of the liner 102, the gap area between the fiber bundles and the body area of ​​the liner, which is the inner shell, are calculated using image software or a measuring tape. When calculating the area from an image, an automatic program using an algorithm such as a color tone difference may be used, or the image may be visually trimmed. Also, it is not necessary for the entire liner 102 to be captured in one image, and multiple images may be joined together. If the gaps 402 between the resin-impregnated fiber bundles cannot be measured during molding, the tank after hardening may be disassembled to measure the width of the resin-impregnated fiber bundles 403 and the gaps 402 between the resin-impregnated fiber bundles. Specifically, the tank 101 is cut in the axial direction 204 of the tank to separate the liner 102 and the reinforcing layer 103, and then an image of the reinforcing layer 103 is obtained from the liner 102 side, and the gap area between the fiber bundles and the body area of ​​the liner 102, which is the inner shell, are calculated. As long as the shape of the reinforcing layer 103 is maintained, the reinforcing layer 103 may be separated by applying force between the layers or applying heat to burn off the resin.

[0035] In the present invention, adjacent wound around the hoop layer Between resin-impregnated fiber bundles provided in the The minimum value of the gap 402 is Lmin (mm), the Between resin-impregnated fiber bundles provided in theThe the maximum value of the gap 402 is Lmax (mm), and the adjacent wound around the hoop layer average width of the resin-impregnated fiber bundles adjacent to the provided in the gap 402 is denoted as W (mm). When the the relationship of Lmin / W < 0.5 and 0.01 < Lmax / W < 0.5 is satisfied, 0.01< it is difficult for the resin-impregnated fiber bundles 403 to overlap due to the looseness of the wound resin-impregnated fiber bundles 403 or the positional movement of the resin-impregnated fiber bundles 403 caused by the resin bleeding during curing. Thus, a gap 402 between the resin-impregnated fiber bundles is stably formed. Also, when Lmin / W and Lmax / W satisfy the above . relationship, the gap 402 between the resin-impregnated fiber bundles is less likely to become a major defect, and a decrease in the pressure resistance can be effectively prevented. The lower limit of Lmin / W lower limit is preferably greater than 0.05. The lower limit of Lmax / W is preferably greater than 0.05, more preferably greater than 0.06. The upper limit of Lmin / W is preferably less than 0.45, more preferably less than 0.4. The upper limit of Lmax / W is preferably less than 0.45, more preferably less than 0.4. upper limit When Lmin / W and Lmax / W satisfy the above is relationship, it is difficult for the gap 402 between the resin-impregnated fiber bundles to become a major defect, and a decrease in the pressure resistance can be effectively prevented. The lower limit of Lmin / W is is preferably greater than 0.05. The lower limit of Lmax / W is preferably greater than 0.05, more preferably greater than 0.06. The upper limit of Lmin / W is preferably less than 0.45, more preferably less than 0.4. The upper limit of Lmax / W is preferably less than 0.45, more preferably less than 0.4. is is preferably greater than 0.05, more preferably greater than 0.06. The upper limit of Lmin / W is preferably less than 0.45, more preferably less than 0.4. The upper limit of Lmax / W is preferably less than 0.45, more preferably less than 0.4. than is preferably less than 0.45, more preferably less than 0.4. The upper limit of Lmax / W is is preferably less than 0.45, more preferably less than 0.4. than is preferably less than 0.45, more preferably less than 0.4. is is preferably less than 0.45, more preferably less than 0.4. than is preferable.

[0036] Here, a method for measuring the gap 402 between the resin-impregnated fiber bundles and the width of the resin-impregnated fiber bundle 403 will be described with reference to FIG. 5. The gap 402 between the resin-impregnated fiber bundles and the width of the resin-impregnated fiber bundle 403 can be measured by temporarily stopping the filament winding molding machine while winding the resin-impregnated fiber bundle 403 around the liner 102. The largest gap (hereinafter sometimes referred to as the "largest gap") 601 between the resin-impregnated fiber bundles is found visually, and the gap is measured. As long as the gap can be measured, there is no limitation to the method, such as a caliper or a laser meter. Starting from the largest gap found, the gap 402 between the resin-impregnated fiber bundles is observed along the axial direction 204 of the liner, and the width of the largest gap 601 is set to Lmax, and the width of the smallest gap (hereinafter sometimes referred to as the "smallest gap") 603 between the resin-impregnated fiber bundles in the same axial direction 204 as the largest gap 601 is set to Lmin. Next, the width of the resin-impregnated fiber bundle 403 adjacent to the maximum gap 601 is measured (at two locations), and the width of the resin-impregnated fiber bundle 403 adjacent to the minimum gap 603 is also measured in the same manner. The measured values ​​of the width at four locations are averaged to obtain the average width W of the resin-impregnated fiber bundle 403. Then, Lmin / W and Lmax / W are calculated using the obtained Lmin, Lmax, and W. Here, when there is an overlap 605 between the resin-impregnated fiber bundles along the axial direction 204 of the liner, Lmin is defined as 0. Here, when Lmin is 0, the average width W of the resin-impregnated fiber bundle 403 is the average value of the widths (at two locations) of only the resin-impregnated fiber bundle 403 adjacent to the maximum gap. Furthermore, when there is no gap between the resin-impregnated fiber bundles 403 at both ends of the gap of the maximum resin-impregnated fiber bundle, the average width W of the resin-impregnated fiber bundle 403 is defined as none. If the resin-impregnated fiber bundle 403 has no average width W, the Lmin / W and Lmax / W at the measurement location are both null. Next, a point rotated approximately 1° in the liner circumferential direction 202 from the gap used as the measurement starting point is set as the starting point, and Lmin / W and Lmax / W are measured from this starting point along the liner axial direction 204 using the method described above. This measurement is repeated around the entire circumference of the liner in the circumferential direction 202, and the minimum Lmin / W and maximum Lmax / W are found from all the measured values ​​obtained.When there are no gaps in the resin-impregnated fiber bundle 403 at any measurement location, both Lmin / W and Lmax / W are defined as 0.

[0037] Furthermore, in the present invention, it is important that there is at least one location where the resin-impregnated fiber bundles 402 are wound without gaps in the hoop layer 201. If gaps are provided in the hoop layer 201, the resin-impregnated fiber bundles 403 do not overlap, so that uniform tension is applied to the resin-impregnated fiber bundles 403 and fiber alignment can be adjusted. However, cracks that occur when pressure is applied may propagate throughout the tank 101 and cause destruction at low pressure. Therefore, unless there is at least one location where the resin-impregnated fiber bundles 403 are wound without gaps, the propagation of cracks is not suppressed and the pressure resistance of the tank 101 cannot be improved.

[0038] In the present invention, the weight ratio of the resin contained in the reinforcing layer 103 (=weight of matrix resin in the resin-impregnated fiber bundle 403 / total weight of the resin-impregnated fiber bundle 403) is preferably 21 to 30%. The weight ratio of the resin contained in the reinforcing layer 103 is more preferably 22.5 to 28.5%. When the weight ratio of the resin contained in the reinforcing layer 103 is within the above-mentioned preferable range, the amount of resin in the resin-impregnated fiber bundle 403 is sufficient, and the gaps provided between the resin-impregnated fiber bundles 403 are unlikely to remain as voids, effectively preventing a decrease in pressure resistance, while the resin-impregnated fiber bundles 403 are unlikely to spread when wound around a liner, making it easy to form stable gaps.

[0039] The resin used in the present invention preferably has a viscosity of 10 to 150 Pa·s at 25° C. When the resin viscosity is in the above-mentioned preferred range, the resin-impregnated fiber bundles 403 do not easily spread when wound around a liner, and gaps can be easily formed stably, while the resin is easily impregnated, and gaps provided between the resin-impregnated fiber bundles 403 are unlikely to remain as voids, effectively preventing a decrease in pressure resistance.

[0040] Here, the fiber bundle and the resin used in the present invention will be described.

[0041] Examples of the fibers constituting the fiber bundle used in the present invention include glass fibers, carbon fibers, graphite fibers, aramid fibers, boron fibers, alumina fibers, and silicon carbide fibers. Two or more of these reinforcing fibers may be mixed and used. In order to obtain a molded product with higher strength, it is a preferred embodiment to use carbon fibers in the fiber bundle.

[0042] In the present invention, any type of carbon fiber can be used depending on the application. However, since a molded product having high strength can be obtained, it is preferable to use a carbon fiber having a tensile modulus of 3 to 8 GPa in a strand tensile test according to the method described in JIS R 7601 (1986).

[0043] The resin used in the present invention is preferably a liquid resin. Specifically, in order to obtain the heat resistance and environmental resistance required for the tank, it is preferable to use an epoxy resin composition containing an epoxy resin and a curing agent. In order to shorten the curing time, it is also possible to add a curing catalyst as appropriate.

[0044] An example of a filament winding molding apparatus used in the present invention is shown in Fig. 6. Fig. 6 is a schematic diagram for explaining the overall configuration of an example of a molding flow in the tank manufacturing method of the present invention.

[0045] The molding flow 701 mainly shows that a creel roller 704 which is responsible for the process of feeding out the fiber bundle 703 from the bobbin 702, a resin impregnation section including a resin impregnation roller 705, a resin impregnation tank 706 and a guide roller 707 which are responsible for the resin impregnation process of impregnating the fiber bundle 703 with resin, a feed eye 708 which is responsible for the winding process of winding the resin-impregnated fiber bundle 703, a liner 102 and a fixed shaft 709 which connects the molding device and the liner 102 are arranged in this order. Note that, although only one bobbin 702 is illustrated in Fig. 7, the present invention is not limited to this, and multiple bobbins 702 can be arranged.

[0046] A towpreg that has been impregnated with resin in advance in a separate process may be used as the bobbin 702. When a towpreg is used, the resin impregnation process can be omitted.

[0047] The tank manufactured by the present invention is suitable for use not only in hydrogen gas vehicles and natural gas vehicles, but also in ships and aircraft, stationary models fixed on the ground, and air respirators used by hospitals and firefighters, etc. The substances stored in the tank may be gases such as nitrogen, oxygen, argon, liquefied petroleum gas, and hydrogen, or liquefied versions of the above substances. EXAMPLES

[0048] <Method for evaluating fracture toughness of resin used in tanks> The resin to be used in the tank was degassed in a vacuum before curing, and then cured in a mold set to a thickness of 6 mm using a 6 mm Teflon (registered trademark) spacer for the time and temperature described in the Examples and Comparative Examples to obtain a 6 mm thick cured resin plate. The obtained cured resin plate was processed into a test piece shape described in ASTM D5045-99, and then an SENB test was performed according to ASTM D5045-99. At this time, the number of samples was n=16, and the average value was used as the fracture toughness value.

[0049] <Method for evaluating the viscosity of resin used in tanks> The viscosity of the resin before hardening used in the tank was measured in accordance with the "Method of measuring viscosity using a cone-plate type rotational viscometer" in JIS Z8803 (2011) using an E-type viscometer (TVE-22HT manufactured by Toki Sangyo Co., Ltd.) equipped with a standard cone rotor (1°34' x R24) at 25°C and a rotation speed of 5 revolutions per minute, and the average value of five measurements was used.

[0050] <How to make towpregs> Using a towpreg manufacturing device equipped with a creel, kiss roll, nip roll, and winder, a resin composition adjusted to a temperature of 25°C was applied to one side of carbon fiber "TORAYCA" (registered trademark), and then the fiber bundle was passed through a nip roll to impregnate the resin composition into the inside of the fiber bundle, thereby obtaining a towpreg. The towpreg bobbin was wound up to 2300 m on a cardboard tube with an initial tension of 600 to 1000 gf and a wind ratio of 6 to 10, to form a cylindrical shape with a winding width of 230 to 260 mm.

[0051] <Method of measuring the gap area between fiber bundles and the body area of ​​the liner (the inner shell)> After pausing the filament winding molding machine during molding, a camera (IXY650, Canon) is used to take a photo of the liner wrapped with the resin-impregnated fiber bundle. This process is repeated each time the liner is rotated 90°, 180°, and 270° in the circumferential direction to take a photo. The captured image is read into the image processing software ImageJ (http: / / imagej.nih.gov / ij / ), and the area is calculated using the software's polygon and measure while visually determining the resin-impregnated fiber bundle parts. Next, the body area of ​​the liner is calculated from the image in the same way. The area of ​​the resin-impregnated fiber bundle is then subtracted from the body area of ​​the liner to calculate the area of ​​the gaps between the fiber bundles. The same process is performed to calculate the area of ​​the gaps between the fiber bundles and the body area of ​​the liner from the remaining images acquired. Finally, the calculated areas are averaged to determine the area of ​​the gaps between the fiber bundles and the body area of ​​the liner from the remaining images acquired.

[0052] <Calculation of the minimum gap Lmin between resin-impregnated fiber bundles, the maximum gap Lmax, and the average width W of the resin-impregnated fiber bundles adjacent to the gap> After temporarily stopping the filament winding molding machine during molding, the maximum point is found by visual inspection, and the width of the point is measured with a vernier caliper (pocket caliper 100 mm, manufactured by Shinwa Sokutei). Starting from that gap, the gaps between the resin-impregnated fiber bundles are observed along the axial direction of the liner, and the maximum value (Lmax) of the gap between the resin-impregnated fiber bundles and the minimum value (Lmin) of the gap between the resin-impregnated fiber bundles are measured. Next, the widths of the resin-impregnated fiber bundles adjacent to Lmax (two points) are measured, and the widths of the resin-impregnated fiber bundles adjacent to Lmin are also measured in the same manner. The measured values ​​of these four widths are averaged to determine the average width W of the resin-impregnated fiber bundles. However, if there is no minimum value (Lmin) of the gap between the fiber bundles at the measurement point, that gap is set to 0, and the average width of the resin-impregnated fiber bundles is the average value of only the maximum gap and the widths of the resin-impregnated fiber bundles adjacent to it (two points). In addition, if there are no gaps between the resin-impregnated fiber bundles at both ends of the maximum gap between the resin-impregnated fiber bundles, the average width of the resin-impregnated fiber bundles is defined as none. If the average width of the resin-impregnated fiber bundles is none, both Lmin / W and Lmax / W at the measurement location will be null and will not be included in the measurement results. Next, a point approximately 1° rotated in the circumferential direction of the liner from the starting gap is set as the starting point, and the gaps between the resin-impregnated fiber bundles are observed along the axial direction of the liner from the starting point, and the maximum gap between the resin-impregnated fiber bundles is set as Lmax, and the minimum gap between the resin-impregnated fiber bundles is set as Lmin. Then, the width W of the resin-impregnated fiber bundles is measured using the method described above, and Lmin / W and Lmax / W are calculated. This measurement is repeated around the entire circumference of the liner, and the maximum Lmax / W and minimum Lmin / W are calculated from the obtained results. If there are no gaps between the resin-impregnated fiber bundles over the entire circumference of the measurement range, both Lmin / W and Lmax / W are defined as 0.

[0053] <Calculation method for strength utilization rate> According to the method described in KHKS0121 (2005), a burst test was performed by applying water pressure to the tank, and the pressure at the time of bursting was measured. According to the formula 5.3.5.3.1(e), the strength of the tank was calculated (hereinafter, calculated strength), and the strength utilization rate of the tank was calculated by the following formula.

[0054] Strength utilization rate (%) = (pressure at burst / calculated strength) x 100 The present invention will now be described in detail with reference to examples. Example 1 A resin composition was obtained by stirring and mixing 88 parts by mass of "jER (registered trademark)" 828, 12 parts by mass of "Deconal (registered trademark)" EX821, 4 parts by mass of "Hypro (registered trademark)" 1300×8 as a terminal carboxy modified acrylic rubber, 17 parts by mass of "Kane Ace (registered trademark)" MX125, 7.4 parts by mass of DICY7T as dicyandiamide, and 2.7 parts by mass of DCMU99 as an aromatic urea compound.

[0055] The fracture toughness of this resin composition was evaluated according to the "Method for evaluating fracture toughness of resins used in tanks" and found to be 2.1 MPa m 0.5The result was as follows. A towpreg with a resin content of 24% was prepared using this resin composition and carbon fiber "TORAYCA (registered trademark)" T910SC-36K-50C. The strand strength of the carbon fiber used was 6200 MPa. A 7.5L aluminum liner with an outer diameter of 160 mm was placed in a filament winding molding device, and the towpreg was wound around the entire liner. As the first layer, a hoop layer at 89° and 91° with respect to the axial direction of the liner was wound to a thickness of 0.79 mm. At this time, the adjacent towpregs were arranged so as not to overlap each other, thereby providing periodic gaps in the first layer. At this time, Lmin / W and Lmax / W were calculated according to "Calculation of the minimum value Lmin of the gap between resin-impregnated fiber bundles, the maximum value Lmax of the gap, and the average width W of the resin-impregnated fiber bundles adjacent to the gap", and Lmin / W was 0.1 and Lmax / W was 0.44. As the second layer, a helical layer was wound to a thickness of 1.07 mm at angles of 18° and 162° to the axial direction of the liner. Furthermore, as the third layer, a hoop layer was wound to a thickness of 0.52 mm at angles of 89° and 91° to the axial direction of the liner to obtain an intermediate body. The intermediate body was rotated in a curing furnace and cured at 150°C for 2 hours to obtain a tank.

[0056] The strength utilization rate of the obtained tank was calculated according to the "Calculation method for strength utilization rate". The strength utilization rate was 98.3%, the burst pressure was 71.5 MPa, and the calculated strength was 72.7 MPa.

[0057] Example 2 A resin composition was obtained by stirring and mixing 21 parts by mass of "jER (registered trademark)" 828, 67 parts by mass of "jER (registered trademark)" 806, 5 parts by mass of "Epotohto (registered trademark)" YDF-2001, 7 parts by mass of TETRAD-X as a xylylenediamine type epoxy resin, 7 parts by mass of "Kane Ace (registered trademark)" MX-125, 5 parts by mass of DICY7T as a dicyandiamide, and 4 parts by mass of DCMU99 as an aromatic urea compound.

[0058] The fracture toughness of this resin composition was evaluated according to the "Method for evaluating fracture toughness of resins used in tanks" and found to be 1.6 MPa m 0.5The result was as follows. A towpreg with a resin content of 24% was prepared using this resin composition and carbon fiber "TORAYCA (registered trademark)" T720SC-36K-50C. The strand strength of the carbon fiber used was 5800 MPa. A 7.5L aluminum liner with an outer diameter of 160 mm was placed in a filament winding molding device, and the towpreg was wound around the entire liner. As the first layer, a hoop layer at 89° and 91° to the axial direction of the liner was wound to a thickness of 0.79 mm. At this time, Lmin / W and Lmax / W were calculated according to "calculation of the minimum value Lmin of the gap between resin-impregnated fiber bundles, the maximum value Lmax of the gap, and the average width W of the resin-impregnated fiber bundles adjacent to the gap", and Lmin / W was 0.19 and Lmax / W was 0.45. As the second layer, a helical layer at 18° and 162° to the axial direction of the liner was wound to a thickness of 1.07 mm. Further, as a third layer, a hoop layer was wound at 89° and 91° to the axial direction of the liner to a thickness of 0.52 mm to obtain an intermediate body. The intermediate body was rotated in a curing oven and cured at 110° C. for 10 hours to obtain a tank.

[0059] The strength utilization rate of the obtained tank was calculated according to the "Calculation method for strength utilization rate". The strength utilization rate was 108.5%, the burst pressure was 73.8MPa, and the calculated strength was 68.0MPa.

[0060] Example 3 A tank was produced in the same manner as in Example 1, except that the resin-impregnated fiber bundles in the first hoop layer were formed with gaps of 0.5 mm between them. At this time, due to the variation in width of the resin-impregnated fiber bundles, there were five "no gaps" in the first hoop layer where the fiber bundles overlapped. At this time, Lmin / W and Lmax / W were calculated according to "calculation of the minimum gap value Lmin between the resin-impregnated fiber bundles, the maximum gap value Lmax, and the average width W of the resin-impregnated fiber bundles adjacent to the gap", and Lmin / W was 0 and Lmax / W was 0.1.

[0061] Next, the strength utilization rate of the obtained tank was calculated according to the "Method for calculating strength utilization rate." The strength utilization rate was 102.1%, the burst pressure was 74.2 MPa, and the calculated strength was 72.7 MPa.

[0062] Comparative Example 1 A tank was produced in the same manner as in Example 1, except that the resin-impregnated fiber bundles of the first hoop layer were stacked by 2.5 mm each. At this time, since there were no gaps in the first hoop layer, Lmin / W and Lmax / W were both set to 0 in accordance with the definitions of "calculation of the minimum gap value Lmin between the resin-impregnated fiber bundles, the maximum gap value Lmax, and the average width W of the resin-impregnated fiber bundles adjacent to the gap".

[0063] The strength utilization rate of the obtained tank was calculated according to the "Method for calculating strength utilization rate." The strength utilization rate was 90.6%, the burst pressure was 65.9 MPa, and the calculated strength was 72.7 MPa. The results showed that the strength utilization rate decreased when the resin-impregnated fiber bundles were overlapped.

[0064] Comparative Example 2 A resin composition was obtained by stirring and mixing 75 parts by mass of "jER (registered trademark)" 828, 40 parts by mass of GAN (manufactured by Nippon Kayaku Kogyo Co., Ltd.), 8 parts by mass of DICY7T (manufactured by Mitsubishi Chemical Co., Ltd.) as a curing agent, and 2 parts by mass of DCMU as a curing assistant.

[0065] The fracture toughness of this resin composition was evaluated according to the "Method for evaluating fracture toughness of resins used in tanks" and found to be 0.72 MPa m 0.5The result was as follows. A towpreg with a resin content of 24% was prepared using this resin composition and carbon fiber "TORAYCA (registered trademark)" T720SC-36K-50C. The strand strength of the carbon fiber used was 5800 MPa. A 7.5L aluminum liner with an outer diameter of 160 mm was placed in a filament winding molding device, and the towpreg was wound around the entire liner. As the first layer, a hoop layer at 89° and 91° to the axial direction of the liner was wound to a thickness of 0.79 mm. At this time, Lmin / W and Lmax / W were calculated according to "calculation of the minimum value Lmin of the gap between the resin-impregnated fiber bundles, the maximum value Lmax of the gap, and the average width W of the resin-impregnated fiber bundles adjacent to the gap", and Lmin / W was 0.09 and Lmax / W was 0.32. As the second layer, a helical layer at 18° and 162° to the axial direction of the liner was wound to a thickness of 1.07 mm. Further, as a third layer, a hoop layer was wound at 89° and 91° to the axial direction of the liner to a thickness of 0.52 mm to obtain an intermediate body. The intermediate body was rotated in a curing oven and cured at 110° C. for 10 hours to obtain a tank.

[0066] The strength utilization rate of the obtained tank was calculated according to the "Calculation method for strength utilization rate". The strength utilization rate was 79.0%, the burst pressure was 53.7 MPa, and the calculated strength was 68.0 MPa. The results showed that when there are gaps between the resin-impregnated fiber bundles, the strength utilization rate decreases when the fracture toughness value is low. [Explanation of symbols]

[0067] 101: Tank 102: Liner 103: Reinforcement layer 201: Hoop layer 202: Circumferential direction 203: Helical layer 204:Tank axial direction 401: Tangent Line 402: Gaps between resin-impregnated fiber bundles 403: Resin-impregnated fiber bundle 601: Largest gap between resin-impregnated fiber bundles 602: Liner axial direction 603: Minimum gap between resin-impregnated fiber bundles in the same axial direction as 601 604: Circumferential direction of liner 605: Overlap of resin-impregnated fiber bundles 701: Molding flow 702: Bobbin 703: Fiber bundle 704: Creel roller 705: Resin-impregnated roller 706:Resin impregnation tank 707: Guide roller 708: Feed Eye 709: Fixed axis

Claims

1. A tank having a liner as an inner shell and a reinforcing layer covering an outer surface of the liner, the reinforcing layer being formed by continuously winding a resin-impregnated fiber bundle around the liner, the reinforcing layer being configured by laminating a plurality of hoop layers and a plurality of helical layers arranged on the liner side, at least one of the hoop layers has a gap between adjacent resin-impregnated fiber bundles wound at an angle of 80° or more and 110° or less with respect to the axial direction of the liner, and at least one portion in the helical layer has adjacent resin-impregnated fiber bundles wound without gaps at an angle of greater than 0° and less than 80°, or greater than 110° and less than 180° with respect to the axial direction of the liner, and the toughness value of the resin constituting the tank is 1.0 MPa m ０．５ The tank is as above, wherein the ratio of the total area exposed from the gaps between adjacent resin-impregnated fiber bundles wound around the hoop layer to the surface area of ​​the body of the liner is greater than 0% and less than 50%, and when the minimum value of the gaps between adjacent resin-impregnated fiber bundles wound around the hoop layer is Lmin (mm), the maximum value is Lmax (mm), and the average width of the resin-impregnated fiber bundles adjacent to the gaps between adjacent resin-impregnated fiber bundles wound around the hoop layer is W (mm), the tank satisfies the relationships of 0.01<Lmin / W<0.5 and 0.01<Lmax / W<0.

5.

2. A tank as described in claim 1, wherein the gaps provided between adjacent resin-impregnated fiber bundles wound around at least one of the hoop layers are provided only in the innermost hoop layer that contacts the liner.

3. 3. The tank according to claim 1, wherein there is at least one location where there is no gap between adjacent resin-impregnated fiber bundles wound around the hoop layer.

4. 4. The tank according to claim 1, wherein the weight percentage of the resin contained in the reinforcing layer is 21% to 30%.

5. 5. The tank according to claim 1, wherein the viscosity of the resin contained in the resin-impregnated fiber bundle is 10 to 150 Pa·s at 25°C.

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