Electroconductive circuit panel for unfolding antenna

Abstract

[Problem] To address the problem of providing an electroconductive circuit panel for an unfolding antenna that makes it possible to provide a highly reliable antenna capable of maintaining shape stability and high transmission / reception performance when unfolded, without deterioration of a circuit or a panel even with repeated folding and unfolding. [Solution] Provided is an electroconductive circuit panel for an unfolding antenna, which includes a panel composite material configured from a fiber base material and an electroconductive circuit pattern formed on the fiber base material, and which can assume a folded state and an unfolded state, wherein: there are provided a soft region that exhibits a low bending strength and a hard region that exhibits a bending strength higher than that of the soft region; the electroconductive circuit pattern has a resistance increase rate of 600% or less in the soft region, as measured in an MIT bending test in conformance with JIS-P8115; and the electroconductive circuit panel for the unfolding antenna can be folded along the soft region.

Description

Conductive circuit panel for deployable antenna

[0001] The present invention relates to a conductive circuit panel for a deployable antenna that can be used for artificial satellites, etc. More specifically, the present invention relates to a conductive circuit panel for a deployable antenna that is highly reliable and in which deterioration of the folded portions is suppressed.

[0002] As satellite communications expand, larger satellite antennas are desired, but there is limited storage space at launch, so they are stored in a small, folded state and then deployed in orbit after launch to become antennas.

[0003] Such deployable antennas must be able to deploy reliably and provide high transmission and reception accuracy after deployment. However, repeated folding and unfolding can cause physical deterioration of the panels in the folding (bending) areas and degradation of the antenna's performance.

[0004] In recent years, deployment methods for such large antennas have been attracting worldwide attention, and various deployment methods have been proposed. Patent Document 1 discloses a deployable membrane structure for an antenna that has a high-rigidity region and a low-rigidity region.

[0005] In either case, to be able to fold and store it compactly and to transmit and receive with high reliability after deployment, it is necessary to provide the appropriate rigidity and high bending resistance of the folded parts. Deterioration of the folded parts can reduce the accuracy of transmission and reception and the physical strength of the entire antenna.

[0006] Japanese Patent Application Laid-Open No. 2021-530126

[0007] An object of the present invention is to provide a conductive circuit panel for a deployable antenna that can provide a highly reliable antenna without deterioration of the circuit or panel even when repeatedly folded and deployed, and that maintains shape stability and high transmission / reception performance when deployed.

[0008] As a result of extensive research, the inventors discovered that the above problem can be solved by setting the bending portion in advance during manufacturing and devising a combination of fiber base material, resin, metal film, etc. so that the bending strength in the area corresponding to the bending portion is lower than the bending strength in other areas, and thus completed the present invention.

[0009] That is, the present invention relates to the following conductive circuit panel for a deployable antenna: (1) A conductive circuit panel for a deployable antenna that includes a panel composite material composed of a fiber substrate and a conductive circuit pattern formed on the fiber substrate, and that can be in a folded state and an unfolded state, the conductive circuit panel having a soft region exhibiting low bending strength and a hard region exhibiting higher bending strength than the soft region, in which the resistance increase rate of the conductive circuit pattern in the soft region is 600% or less in an MIT bending test in accordance with JIS-P8115, and the conductive circuit panel for a deployable antenna can be folded along the soft region.

[0010] (2) The conductive circuit panel for a deployable antenna according to (1), wherein the bending strength of the soft region is 0.19 N or less and the bending strength of the hard region is 0.2 N or more. (3) The conductive circuit panel for a deployable antenna according to (1), wherein the difference in bending strength between the soft region and the hard region is 0.2 N or more.

[0011] (4) The conductive circuit panel for deployable antennas according to (1), wherein the line width of the conductive circuit pattern in the soft region is 1.0 mm or more. (5) The amount of metal in the conductive circuit pattern in the soft region is 3 to 120 μg / mm ２ The conductive circuit panel for a deployable antenna according to (1),

[0012] (6) The conductive circuit panel for a deployable antenna according to (1), wherein a surface resin layer is formed on at least one side of the panel composite material in at least the hard region. (7) The conductive circuit panel for a deployable antenna according to (6), wherein a surface resin layer is formed on at least one side of the panel composite material in both the soft region and the hard region, and the ratio of the resin amount of the surface resin layer in the soft region to the resin amount of the surface resin layer in the hard region is 1:20 or more (mass ratio).

[0013] (8) The conductive circuit panel for an expandable antenna according to (6), wherein the surface resin layer is made of polyurethane resin. (9) The conductive circuit panel for an expandable antenna according to (1), wherein the panel composite material includes a plated metal film formed on the conductive circuit pattern.

[0014] The conductive circuit panel for a deployable antenna of the present invention is stored in a folded state and can be unfolded when in use to expand the transmission and reception surface. A single panel has a hard region and a soft region, and by folding along the soft region, which has low bending strength and flexibility and has circuits that are pre-strengthened to withstand bending, deterioration of the circuits and panel due to repeated folding and unfolding is prevented and shape stability is maintained when unfolded. By pre-setting the folding portions from the time of manufacture, a highly reliable deployable antenna can be obtained.

[0015] Fig. 1 is a plan view showing an example of a conductive circuit panel for an expandable antenna of the present invention. Fig. 2 is a view showing the example of the conductive circuit panel for an expandable antenna of the present invention shown in Fig. 1 in a state during folding. Fig. 3 is a view showing the example of the conductive circuit panel for an expandable antenna of the present invention shown in Fig. 1 in a completely folded state. Fig. 4 is a view showing a conductive circuit pattern in the example of the conductive circuit panel for an expandable antenna of the present invention shown in Fig. 1. Fig. 5 is a schematic view showing a method for measuring bending strength in the present invention. Fig. 6 is a schematic view of a pressure tool used to measure bending strength in the present invention.

[0016] The conductive circuit panel of the present invention includes a panel composite material composed of a fiber substrate and a conductive circuit pattern formed on the fiber substrate, and has a soft region exhibiting low bending strength and a hard region exhibiting higher bending strength than the soft region, and in the soft region, the resistance increase rate of the conductive circuit pattern in an MIT bending test in accordance with JIS-P 8115 is 600% or less. This conductive circuit panel is for a deployable antenna that can be in a folded state and an unfolded state, and is foldable along the soft region.

[0017] A plan view of an example of a conductive circuit panel for a deployable antenna of the present invention is shown in Figure 1. In Figure 1, 1 is a conductive circuit panel, 2(a) and 2(b) are hard regions, 3(a) and 3(b) are soft regions, and M is a central portion.

[0018] Fig. 2 shows the conductive circuit panel of Fig. 1 in the middle of being folded, and Fig. 3 shows the conductive circuit panel of Fig. 1 in a completely folded state. Fig. 4 is a diagram showing an example of the formation of a conductive circuit pattern in the conductive circuit panel of Fig. 1, which may not be visible because it is normally formed under the surface resin layer, for ease of understanding, and in the figure, reference numeral 4 denotes the conductive circuit pattern.

[0019] In Fig. 1, the left and right soft regions 3(a) are folded inward (valley folds relative to the plane), the diagonally arranged soft region 3(b) is folded inward, and the top and bottom edges are brought to the center while the central portion M where the soft regions intersect is pulled up toward the front, making the bag small and thin, and it can be stored in a shape that is easy to unfold (Fig. 3). However, this is one embodiment of the present invention, and the present invention is not limited to this.

[0020] (1) Fiber Substrate The conductive circuit panel of the present invention includes a panel composite material comprising a fiber substrate and a conductive circuit pattern formed thereon. As the fiber substrate, a fabric made of a fiber material is preferably used.

[0021] Specific fiber materials include, but are not limited to, natural fibers such as cotton, linen, wool, and silk; regenerated fibers such as rayon and cupra; semi-synthetic fibers such as acetate and triacetate; polyamide (nylon 6, nylon 66, etc.) fibers; polyester (polyethylene terephthalate, polytrimethylene terephthalate, etc.) fibers; synthetic fibers such as polyurethane, polyacrylic, aramid, and polyparaphenylene benzobisoxazole; and inorganic fibers such as glass fiber, basalt fiber, and carbon fiber. Synthetic fibers are preferred as fiber materials in terms of versatility, flexibility, and strength. Among these, polyimide fibers are particularly preferred for aerospace applications, and polyester fibers are particularly preferred for other general applications.

[0022] The thickness of the fiber substrate is not particularly limited, but is preferably 10 to 5000 μm, more preferably 50 to 1000 μm.

[0023] The fiber substrate may be any of woven fabric, knitted fabric, nonwoven fabric, etc. The shape of the threads constituting the substrate is not particularly limited.

[0024] (2) Conductive Circuit Pattern A conductive circuit pattern is formed on the surface of the fiber substrate to form a composite material for panels. The conductive circuit pattern can be formed on one side (front or back) of the fiber substrate, or on both sides. When a relatively thick fiber substrate or a fabric with low permeability is used, the conductive circuit pattern can be formed on only one side of the fiber substrate. When a conductive circuit pattern is formed on both sides of the fiber substrate, the resistance value can be kept low and the antenna sensitivity can be increased. Preferably, the conductive circuit pattern is formed on both sides of the fiber substrate.

[0025] The conductive circuit pattern may be formed not only on the surface of the fiber substrate but also in the thickness direction of the fiber substrate. The conductive circuit pattern may be formed so as to penetrate from the front surface to the back surface of the fiber substrate. The conductive circuit pattern may be formed by a single conductive circuit pattern or by connecting multiple conductive circuit patterns.

[0026] The conductive circuit pattern contains a metal. The metal contained in the conductive circuit pattern is not particularly limited, but can be one selected from gold, silver, copper, nickel, tin, iron, aluminum, platinum, palladium, rhodium, ruthenium, iridium, osmium, indium, rubidium, and cobalt, or a mixture or alloy of two or more metals. Among these, gold, silver, copper, nickel, and tin are preferred. Among these, copper is particularly preferred because of its high conductivity and cost-effectiveness.

[0027] The form of the metal contained in the conductive circuit pattern is not particularly limited. In order to form a more highly precise conductive circuit pattern, the metal preferably contains metal particles, and more preferably contains metal particles having an average particle size of 1 to 200 nm.

[0028] A plating process using these metal particles as nuclei may be carried out to deposit the same or different metals, thereby increasing the amount of metal and improving conductivity.

[0029] The average particle size of metal particles refers to the primary particle size without taking into account aggregation, and can be expressed as the arithmetic mean of the equivalent sphere particle diameters (diameters when each particle is converted into a sphere of the same volume) of 100 or more particles measured using any method known in the technical field, for example, a transmission electron microscope (TEM). Specifically, the "average particle size of metal particles" in the present invention means the arithmetic mean of the equivalent sphere particle diameters of 100 metal particles measured using a transmission electron microscope.

[0030] The conductive circuit pattern can be freely shaped. A single conductive circuit pattern or a combination of multiple conductive circuit patterns can be used to form a desired conductive circuit. This allows for the compact manufacture of high-definition, complex conductive circuits at high density.

[0031] The conductive circuit pattern of the present invention is formed on a fibrous substrate using an ink composition that preferably contains a metal.

[0032] The conductive circuit pattern is preferably formed by a printing method. Examples of printing methods include screen printing, gravure printing, inkjet printing, xerography, stamping, flexographic printing, offset printing, painting, and airbrushing, and any of these methods uses an ink composition containing a metal. Among these methods, inkjet printing is particularly preferred.

[0033] The metal-containing ink composition is preferably an ink composition containing the above-described metal particles. It is particularly preferable that the ink composition contains metal particles with an average particle diameter of 1 to 200 nm. When an ink composition containing metal particles with such an average particle diameter is applied to the surface of a fibrous substrate (fabric), the metal particles penetrate not only into the gaps in the structure of the fibrous substrate, but also into the gaps between the threads that make up the fibrous substrate, i.e., the gaps between the single fibers. As a result, the uniformity of the formed conductive pattern is improved, and metal detachment is less likely to occur.

[0034] The ink composition may be a dispersion of metal particles. The dispersion of metal particles refers to a solution in which metal particles are appropriately dispersed in a solvent. Metal particles in a solvent tend to aggregate, so adding a dispersant to coat the surfaces of the metal particles can suppress aggregation and stabilize the dispersion of the metal particles.

[0035] The solvent is not particularly limited, and examples thereof include water, alcohol-based solvents (monoalcohol-based solvents, diol-based solvents, polyhydric alcohol-based solvents, etc.), hydrocarbon-based solvents, ketone-based solvents, ester-based solvents, ether-based solvents, glyme-based solvents, halogen-based solvents, etc. These solvents may be used alone or in combination of two or more.

[0036] Any known dispersant may be appropriately selected and used. Examples include, but are not limited to, amine compounds and thiol compounds. The amine compound is preferably an aliphatic amine compound, more preferably an aliphatic amine compound having 4 to 10 carbon atoms in the alkyl moiety. Examples of aliphatic amine compounds include alkylamines such as octylamine, dodecylamine, and hexadecylamine, and alkenylamines such as oleylamine. The thiol compound is preferably an aliphatic thiol compound. Examples of aliphatic thiol compounds include alkylthiols such as hexanethiol, pentanedithiol, decanethiol, and dodecanethiol. The dispersant may be used alone or in combination of two or more. Using a dispersant with a small number of carbon atoms allows for easy elimination or decomposition under easy conditions.

[0037] The blending ratio of the metal particles in the ink composition is preferably 0.1 to 70% by mass, more preferably 1 to 60% by mass, and even more preferably 10 to 50% by mass, based on the total mass of the ink composition.

[0038] In addition to the metal particles, solvent, and dispersant, the ink composition may contain known additives such as thickeners and stabilizers for the purpose of adjusting printability.

[0039] The conductive circuit pattern in the conductive circuit panel of the present invention exhibits high flex resistance at least in the soft region. Specifically, the flex resistance of the conductive circuit pattern in the soft region is preferably 600% or less, more preferably 550% or less, and most preferably 500% or less, as measured by the MIT flex test in accordance with JIS-P8115.

[0040] The lower limit of the resistance increase rate of the conductive circuit pattern in the soft region is not particularly limited, but is preferably 1% or more, more preferably 50% or more, even more preferably 120% or more, and particularly preferably 200% or more. By increasing the bending resistance of the conductive circuit pattern in the soft region, the reliability of the circuit does not decrease even when repeatedly folded and unfolded.

[0041] The flex resistance of the conductive circuit pattern in the hard region is not particularly limited. The flex resistance in the hard region can be increased to the same level as that in the soft region, but the conductive circuit pattern may be formed in the hard region without regard to flex resistance. The flex resistance of the conductive circuit pattern in the hard region may be lower than that in the soft region. For example, by using a thin line whose line width is narrower in the conductive circuit pattern in the hard region than in the soft region, the flexibility of the conductive circuit can be increased and space can be saved.

[0042] The resistance increase rate of the conductive circuit pattern in the hard region in an MIT bending test is not particularly limited, and if it is acceptable for the bending resistance of the conductive circuit pattern in the hard region to be lower than that in the soft region, it may be more than 600%, or even 650% or more.

[0043] There are no particular limitations on the means for increasing the flex resistance of the conductive circuit pattern, but examples include increasing the line width of the pattern, increasing the amount of metal in the pattern, and increasing the metal thickness of the pattern.

[0044] An example of a method for widening the line width of the conductive circuit pattern is an inkjet process. The line width of the conductive circuit pattern in the soft region is preferably 1.0 mm or more, more preferably 3.0 mm or more, and particularly preferably 5.0 mm or more. There is no particular upper limit to the line width in the soft region, but it is preferably 80 mm or less.

[0045] The line width of the conductive circuit pattern in the hard region is not particularly limited, but may be 4.9 mm or less, or may be 2.9 mm or less. If it is acceptable for the hard region to have lower flex resistance than the soft region, it may be 1.0 mm or less. The lower limit of the line width of the conductive circuit pattern in the hard region is not particularly limited, but is preferably 0.3 mm or more.

[0046] In the conductive circuit panel of the present invention, the bending strength of the soft region is reduced to provide flexibility while increasing the strength of the circuit, while the bending strength of the hard region, which is responsible for the main part of the antenna performance, is increased compared to the soft region, thereby increasing the degree of freedom of the conductive circuit pattern without worrying about strength, thereby maintaining a well-balanced overall antenna performance. Furthermore, deterioration of the circuit and panel due to folding is prevented, and shape stability can be maintained when unfolded, resulting in a highly reliable deployable antenna.

[0047] When the flex resistance of the hard region may be lower than that of the soft region, the ratio of the line width of the soft region to the line width of the hard region is not particularly limited, but is preferably 5-20:1-3.

[0048] A method for increasing the amount of metal in the conductive circuit pattern includes lamination printing of conductive layers by inkjet printing or screen printing. The number of laminations or the amount of ink ejected can be increased in advance during printing.

[0049] The metal content of the conductive circuit pattern in the soft region is preferably 3.0 μg / mm ２ More preferably, 5.0 μg / mm ２ More preferably, 10 μg / mm ２ More preferably, 30 μg / mm ２ More preferably, 35 μg / mm ２ There is no particular upper limit, but it is preferably 120 μg / mm ２ Less than 100 μg / mm ２ Below 50 μg / mm ２ The following is the result.

[0050] The amount of metal in the conductive circuit pattern in the hard region is not particularly limited, but is preferably 39.9 μg / mm ２ or less, 29.9 μg / mm ２ The lower limit is not particularly limited, but it may be 3 μg / mm ２ It may be 5 μg / mm or more, and further ２ The amount of metal in the hard region may be equal to or less than that in the soft region.

[0051] The ratio of the amount of metal in the conductive circuit pattern in the soft and hard regions is not particularly limited, but the mass ratio of [amount of metal in the soft region] to [amount of metal in the hard region] is preferably 3:1 or less, more preferably 2:1 or less, and even more preferably 1.2:1 or less. The lower limit of the mass ratio of [amount of metal in the soft region] to [amount of metal in the hard region] is not particularly limited, but is preferably 0.8:1 or more, more preferably 0.9:1 or more, and even more preferably 1:1 or more.

[0052] The amount of metal in the conductive circuit pattern is expressed as the amount of metal per unit area (μg / mm ２ Here, the term "area" refers to the area of ​​the composite material for panels when viewed in plan, without taking into consideration the thickness, voids, and surface irregularities of the composite material for panels containing a fiber base material.

[0053] The amount of metal in each region (soft region and hard region) of the conductive circuit pattern is measured by the following method. That is, the region to be measured is cut out together with the fiber substrate to form a sample, and its area is measured. As mentioned above, the area is the area when viewed in a plan view, without taking into account thickness, voids, or surface irregularities. Next, the cut-out sample is immersed in nitric acid diluted to a concentration of 50% by mass to completely dissolve the metal layer. The nitric acid aqueous solution thus obtained, with the metal dissolved, is diluted to a predetermined concentration, and the metal concentration in the aqueous solution is measured by atomic absorption spectrometry. The amount of metal per unit area (μg / mm) is calculated from the area of ​​the cut-out sample and the metal concentration obtained by atomic absorption spectrometry. ２ ) is calculated.

[0054] (3) Plated Metal Film In the present invention, if necessary, a plated metal film may be formed on the conductive circuit pattern by further performing a metal plating process. This makes it possible to further increase the amount of metal in the conductive circuit pattern, thereby producing a conductive circuit panel with enhanced conductivity. Furthermore, the adhesive strength of the conductive circuit pattern to the fiber substrate can be increased, making it less likely to fall off. In the present invention, when a plated metal film is formed on the conductive circuit pattern in this manner, the conductive circuit pattern and the plated metal film may be collectively referred to as the "conductive circuit pattern."

[0055] The metal plating process may be an electroplating process or an electroless plating process, either of which may be used. Preferably, an electroless plating process is used. The metal used in the plating process may be the same as or different from the metal particles contained in the ink composition. Preferably, the metal particles contained in the ink composition and the metal used in the plating process are the same. Furthermore, it is preferable that both the metal particles contained in the ink composition and the metal used in the plating process are copper.

[0056] The metal plating treatment can be carried out by a conventionally known method, and there are no particular limitations on the chemicals, equipment, conditions, etc. Optimal conditions can be selected depending on the type and amount of metal to be deposited.

[0057] For example, when performing electroless plating, a conductive circuit pattern can be printed on a fiber substrate using an ink composition, the solvent of the ink composition can be removed by heating or drying, and the fiber substrate can then be immersed in an electroless plating solution to perform the electroless plating.

[0058] In the present invention, when a plated metal film is formed on a conductive circuit pattern as needed, the amount of metal in each of the soft and hard regions is the sum of the amount of metal derived from a metal-containing ink composition applied by inkjet printing or the like and the amount of metal derived from a plated metal film deposited by plating (hereinafter referred to as the "total metal amount").

[0059] The total metal content of the soft areas in the plated conductive circuit pattern is preferably 3.0 μg / mm ２ More preferably, 5.0 μg / mm ２ More preferably, 10 μg / mm ２ More preferably, 30 μg / mm ２ More preferably, 35 μg / mm ２ There is no particular upper limit, but it is preferably 120 μg / mm ２ Less than 100 μg / mm ２ Below 50 μg / mm ２ The following is the result.

[0060] By increasing the total metal content in the soft region, the flexibility of the soft region can be increased, and it becomes possible to prevent the reliability of the circuit from decreasing even when repeatedly bent and unfolded.

[0061] The amount of metal in the conductive circuit pattern in the hard region when plated is not particularly limited, but is preferably 39.9 μg / mm ２ or less, 29.9 μg / mm ２ The lower limit is not particularly limited, but it may be 3 μg / mm ２ It may be 5 μg / mm or more, and further ２ The amount of metal in the hard region may be equal to or less than that in the soft region.

[0062] The conductive circuit pattern formed on the fiber substrate can have good conductivity, with a surface resistance value of preferably less than 10 MΩ / □, more preferably less than 10 KΩ / □.

[0063] (4) Soft Region and Hard Region The conductive circuit panel of the present invention has a (flexible) soft region exhibiting low bending strength and a (hard) hard region exhibiting higher bending strength than the soft region.

[0064] The bending strength of the conductive circuit panel in the soft region is preferably 0.19 N or less, more preferably 0.15 N or less, even more preferably 0.1 N or less, and particularly preferably 0.07 N or less. There is no particular lower limit, but it is preferably 0.01 N or more.

[0065] The bending strength of the conductive circuit panel in the hard region is preferably 0.2 N or more, more preferably 0.3 N or more. There is no particular upper limit, but it is preferably 20 N or less, more preferably 10 N or less. The bending strength is measured using a bending stress measurement method based on the loop compression method (JIS L1096 bending resistance measurement). Details will be described later in the "Method for evaluating bending strength" section.

[0066] In the present invention, the difference between the bending strength of the conductive circuit panel in the soft region and the bending strength of the conductive circuit panel in the hard region is preferably 0.2 N or more, more preferably 0.3 N or more.

[0067] The ratio of the bending strength of the conductive circuit panel in the soft region to the bending strength of the conductive circuit panel in the hard region is not particularly limited, but the lower limit [bending strength of soft region]:[bending strength of hard region] is preferably 1:3 or more, more preferably 1:5 or more, and even more preferably 1:7 or more, and the upper limit is preferably 1:300 or less, more preferably 1:200 or less.

[0068] The conductive circuit panel of the present invention can be folded along the highly flexible soft region and exhibits excellent flex resistance even when repeatedly folded and unfolded, preventing a decrease in conductivity due to breakage or deterioration in antenna performance. The hard region has high rigidity, allowing the conductive circuit panel to maintain its shape and stabilize in the unfolded state. Furthermore, because the conductive circuit pattern in the soft region has high flex resistance, antenna performance does not deteriorate even when the panel is bent along the soft region, resulting in a conductive circuit panel for an unfoldable antenna that does not lose reliability even when the entire antenna is repeatedly folded and unfolded.

[0069] (5) Surface Resin Layer In the present invention, a surface resin layer can be provided in at least the hard region of the conductive circuit panel. That is, in the present invention, it is preferable that a surface resin layer is formed in at least the hard region of a panel composite material composed of a fiber substrate and a conductive circuit pattern. By providing a surface resin layer, not only can the strength and durability of the conductive circuit panel be maintained, but depending on how the surface resin layer is provided, it is also possible to separately set soft and hard regions with different bending strengths within the same panel.

[0070] The resin constituting the surface resin layer is not particularly limited, but examples thereof include polyurethane resin, polyester resin, silicone resin, epoxy resin, acrylic resin, polyimide resin, etc. Among these, polyurethane resin or epoxy resin is preferred from the viewpoint of rigidity characteristics, durability, etc., and polyurethane resin is particularly preferred. The resin may be blended with a curing agent, a flame retardant, a corrosion inhibitor, etc. as necessary.

[0071] The surface resin layer must be formed on at least one side of the panel composite material at least in the hard region, and may be formed on only one side or both sides of the panel composite material.

[0072] Furthermore, the surface resin layer may be formed on the side of the panel composite material where the conductive circuit pattern is present, or on the side where the conductive circuit pattern is not present. That is, in the case of a panel composite material in which a conductive circuit pattern is formed on only one side of the fiber substrate, when the surface resin layer is formed on only one side of the panel composite material, the surface resin layer may be formed only on the side where the conductive circuit pattern is formed, or may be formed only on the side where the conductive circuit pattern is not formed. Preferably, the surface resin layer is formed on the side of the panel composite material where the conductive circuit pattern is formed. More preferably, the surface resin layer is formed on both sides of the panel composite material.

[0073] When the conductive circuit panel of the present invention is used as a communication antenna requiring high sensitivity and precision, forming a surface resin layer on only one side of the panel composite material allows the side without the surface resin layer to be used as the receiving surface during use, which is expected to reduce noise caused by interference and may also contribute to simplifying the process and reducing weight. On the other hand, when considering the durability of the conductive circuit panel and protection of the conductive circuit, forming a surface resin layer on both sides of the panel composite material can also improve durability and the sustainability of antenna performance. Furthermore, in applications where protection of the conductive circuit pattern is not particularly required, forming a surface resin layer only on the side of the panel composite material without the conductive circuit pattern can expose the conductive circuit pattern, which may make it easier to establish contact with an external device or to easily attach and detach the contact.

[0074] The surface resin layer is preferably formed on the surface of at least the hard region of the panel composite material. Alternatively, it may be formed only on the hard region. For example, by forming a surface resin layer on the surface of the hard region and not on the surface of the soft region, the bending strength of the hard region can be increased and the bending strength of the soft region can be relatively decreased.

[0075] The surface resin layer can also be formed on the surface of both the soft region and the hard region of the panel composite. For example, by providing a difference in the amount or thickness of resin in the surface resin layer in the soft region and the amount or thickness of resin in the surface resin layer in the hard region, or by using different types of resin for the surface resin layer in each region, the bending strength of the hard region of the resulting conductive circuit panel can be increased and the bending strength of the soft region can be relatively reduced.

[0076] When the same type of resin is used as the resin constituting the surface resin layer in the soft region and the hard region, the amount of resin in the surface resin layer in the soft region is not particularly limited, but is preferably 0.2 mg / mm ２ or less, more preferably 0.1 mg / mm ２ The lower limit of the resin amount is not particularly limited, but is preferably 0.01 mg / mm ２ More preferably, 0.04 mg / mm ２ It can be more than that.

[0077] The amount of resin in the surface resin layer of the hard region is not particularly limited, but is preferably 0.21 mg / mm ２ More preferably, 0.4 mg / mm ２ More preferably, 1 mg / mm ２ More preferably, 3 mg / mm ２ The upper limit of the amount of resin is not particularly limited, but is preferably 10 mg / mm ２ Less than 7 mg / mm ２ It can be as follows:

[0078] Alternatively, when the same type of resin is used, the thickness of the surface resin layer in the soft region is not particularly limited, but is preferably 120 μm or less, more preferably 90 μm or less, and particularly preferably 60 μm or less. The lower limit of the thickness of the surface resin layer in the soft region is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, and particularly preferably 40 μm or more.

[0079] When the same type of resin is used, the thickness of the surface resin layer of the hard region is not particularly limited, but is preferably 60 μm or more, more preferably 150 μm or more, even more preferably 300 μm or more, and particularly preferably 500 μm or more. The upper limit of the thickness of the surface resin layer of the hard region is not particularly limited, but is preferably 1500 μm or less, more preferably 1200 μm or less, and particularly preferably 900 μm or less.

[0080] When the same type of resin is used, it is desirable that the ratio of the amount of resin in the surface resin layer of the soft region to the amount of resin in the surface resin layer of the hard region is preferably 1:20 or more (mass ratio), more preferably 1:30 to 100 (weight ratio), and particularly preferably 1:50 to 100 (weight ratio).

[0081] When the same type of resin is used, it is desirable that the ratio of the thickness of the surface resin layer in the soft region to the thickness of the surface resin layer in the hard region is preferably 1:8 or more, more preferably 1:10 to 20, and even more preferably 1:12 to 18.

[0082] In the conductive circuit panel of the present invention, the type of resin constituting the surface resin layer formed in the soft region can be different from the type of resin constituting the surface resin layer formed in the hard region. That is, by using a relatively low-rigidity, flexible resin as the resin constituting the surface resin layer in the soft region and a relatively high-rigidity resin as the resin constituting the surface resin layer in the hard region, the bending strength of the hard region can be increased and the bending strength of the soft region can be relatively decreased. This allows the conductive circuit panel to have soft and hard regions with different bending strengths.

[0083] When different types of resins are used in the surface resin layer for the soft region and the hard region, examples of the resins preferably used in the soft region include polyurethane resin, epoxy resin, silicone resin, polyester resin, polyimide resin, etc. Among these, polyurethane resin or epoxy resin is preferred from the viewpoint of rigidity characteristics, durability characteristics, etc., and polyurethane resin is particularly preferred.

[0084] Resins preferably used in the hard region include polyester resins, polyurethane resins, epoxy resins, polyimide resins, and acrylic resins. Among these, polyester resins and acrylic resins are preferred from the viewpoint of rigidity and durability, and polyester resins are particularly preferred.

[0085] The combination of resins for the soft and hard regions is not particularly limited, and can be selected so that the flexibility is preferably different. For example, if a polyester resin is selected for the soft region, a resin with lower flexibility can be selected for the hard region. Also, if a polyester resin is selected for the hard region, a resin with higher flexibility can be selected for the soft region.

[0086] In this way, by selecting the appropriate resin combination, it is possible to minimize the difference in thickness between the soft and hard regions while providing a difference in bending strength, thereby achieving a uniform thickness for the entire conductive circuit panel. The conductive circuit panel of the present invention has a soft region that provides the panel with excellent flexibility while having a conductive circuit pattern with enhanced bending resistance, and a hard region that provides the panel with high bending strength while allowing for the formation of a conductive circuit pattern with a high degree of freedom without worrying about bending resistance. Furthermore, by minimizing the difference in thickness between the two regions and achieving a uniform thickness for the entire conductive circuit panel, an antenna with excellent appearance and usability can be obtained.

[0087] When different types of resins are used in the surface resin layer of the soft region and the hard region, the amount of resin in the surface resin layer of the soft region is not particularly limited, but is preferably 0.2 mg / mm ２ or less, more preferably 0.1 mg / mm ２ The lower limit of the resin amount is not particularly limited, but is preferably 0.01 mg / mm ２ More preferably, 0.04 mg / mm ２ It can be more than that.

[0088] The amount of resin in the surface resin layer of the hard region is not particularly limited, but is preferably 0.1 mg / mm ２ More preferably, 0.12 mg / mm ２The upper limit of the amount of resin is not particularly limited, but is preferably 10 mg / mm ２ Less than 7 mg / mm ２ It can be as follows:

[0089] Alternatively, when different types of resins are used, the thickness of the surface resin layer of the soft region is not particularly limited, but is preferably 80 μm or less, more preferably 65 μm or less, and particularly preferably 52 μm or less. The lower limit of the thickness of the surface resin layer of the soft region is not particularly limited, but is preferably 10 μm or more, and more preferably 20 μm or more.

[0090] The thickness of the surface resin layer in the hard region is not particularly limited, but is preferably 55 μm or more, more preferably 60 μm or more. The upper limit of the thickness of the surface resin layer in the hard region is not particularly limited, but is preferably 1000 μm or less, more preferably 500 μm or less, and particularly preferably 200 μm or less.

[0091] When different types of resins are used, the ratio of the amount of resin in the surface resin layer of the soft region to the amount of resin in the surface resin layer of the hard region is not particularly limited, but is preferably 1:1.5 or more (mass ratio), more preferably 1:2 or more (weight ratio), and particularly preferably 1:2 to 1:3 (weight ratio).

[0092] When different types of resins are used, the ratio of the thickness of the surface resin layer in the soft region to the thickness of the surface resin layer in the hard region is not particularly limited, but is preferably 1:1 or more, and more preferably 1:1 to 1:2.

[0093] Furthermore, for example, even if the type of resin constituting the surface resin layers of both regions is the same, by using different types of curing agents for the resin in the soft region and the resin in the hard region or by varying the amounts of curing agents used, it is possible to increase the bending strength of the hard region and adjust the bending strength of the soft region to be relatively low.

[0094] When the same type of resin is used for the surface resin layer, it is particularly preferable to use a polyurethane resin, which is a reaction product obtained by reacting raw material components for polyurethane resin, including a polyisocyanate component and a polyol component.

[0095] The polyisocyanate component includes diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates.

[0096] The aliphatic or alicyclic diisocyanate preferably has a carbon number of 4 to 30. Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,2,4- (or 2,4,4-) trimethyl-1,6-hexamethylene diisocyanate, and lysine diisocyanate.

[0097] Examples of alicyclic diisocyanates include isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, 1,4-diisocyanate cyclohexane, 1,3-bis(diisocyanate methyl) cyclohexane, and 4,4'-dicyclohexylmethane diisocyanate.

[0098] Examples of aromatic diisocyanates include 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0099] These diisocyanates may be used alone or in combination. Of these, 1,6-hexamethylene diisocyanate is preferred because of its weather resistance and ease of industrial availability. Furthermore, in consideration of the impact on the environment, it is also preferred to use environmentally friendly 1,5-pentamethylene diisocyanate, which is a plant-derived isocyanate.

[0100] The content of the polyisocyanate component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more, per 100 parts by mass of the polyurethane resin raw material component of the present invention, and is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and particularly preferably 70 parts by mass or less.

[0101] Examples of the polyol component include aromatic polyols, alicyclic polyols, aliphatic polyols, polyether polyols, polyester polyols, polylactone polyols, acrylic polyols, epoxy polyols, polycarbonate polyols, urethane polyols, etc. These may be used alone or in combination of two or more.

[0102] Examples of aromatic polyols include bisphenol A, bisphenol F, phenol novolac, and cresol novolac.

[0103] Examples of alicyclic polyols include cyclohexanediol, methylcyclohexanediol, isophoronediol, dicyclohexylmethanediol, and dimethyldicyclohexylmethanediol.

[0104] Examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0105] Examples of polyether polyols include polymers obtained by ring-opening polymerization of at least one alkylene oxide, such as ethylene oxide, propylene oxide, or tetrahydrofuran, in the presence of at least one low-molecular-weight active hydrogen compound having two or more active hydrogens. Examples of low-molecular-weight active hydrogen compounds having two or more active hydrogens include diols such as bisphenol A, ethylene glycol, propylene glycol, butylene glycol, and 1,6-hexanediol, triols such as glycerin and trimethylolpropane, and amines such as ethylenediamine and butylenediamine.

[0106] Examples of polyester polyols include polyester polyol resins obtained by a condensation reaction of a dibasic acid selected from carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, fumaric anhydride, isophthalic acid, and terephthalic acid, either alone or in combination, with a polyhydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin, either alone or in combination; polycaprolactone obtained by ring-opening polymerization of ε-caprolactone and a polyhydric alcohol; and esters of an aliphatic compound having a hydroxyl group, such as castor oil, with a polyhydric alcohol.

[0107] Examples of polylactone polyols include polypropiolactone glycol, polycaprolactone glycol, and polyvalerolactone glycol.

[0108] Examples of acrylic polyols include those obtained by copolymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule with a monomer copolymerizable therewith. For example, (i) a single or mixture of acrylic acids selected from acrylic esters having active hydrogen atoms, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate; methacrylic esters having active hydrogen atoms, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate; methacrylic acids and acrylic acids having polyvalent active hydrogen atoms, such as acrylic acid monoester or methacrylic acid monoester of glycerin, and acrylic acid monoester or methacrylic acid monoester of trimethylolpropane; and (ii) methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid monoester ... Examples of the acrylic polyol resins include acrylic polyol resins obtained by polymerizing, alone or in combination, a monomer selected from the group consisting of acrylic acid esters such as n-butyl methacrylate and 2-ethylhexyl acrylate; and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and n-hexyl methacrylate, in the presence or absence of (iii) a monomer selected from the group consisting of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid, unsaturated amides such as acrylamide and N-methylolacrylamide, and polymerizable monomers such as styrene, vinyltoluene, vinyl acetate, and acrylonitrile, alone or in combination.

[0109] Examples of epoxy polyols include novolak-type, β-methylepichlorohydrin-type, cyclic oxirane-type, glycidyl ether-type, glycidyl ester-type, glycol ether-type, epoxidized aliphatic unsaturated compound-type, epoxidized aliphatic ester-type, polycarboxylic acid ester-type, aminoglycidyl-type, and resorcinol-type epoxy resins.

[0110] Examples of polycarbonate polyols include polyols obtained by dealcoholization reaction of hydroxyl group-containing compounds such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, and nonanediol with diethylene carbonate, dipropylene carbonate, etc. Further examples include polycarbonate polyols obtained using aromatic polyhydric alcohols such as bisphenol A and aliphatic / alicyclic polyhydric alcohols such as 1,6-hexanediol as raw materials.

[0111] Examples of urethane polyols include those having urethane bonds in the polymer produced by the polyaddition reaction of aromatic, aliphatic, or alicyclic diisocyanates with active hydrogen compounds, and having hydroxyl groups on the polymer side chains or terminals.

[0112] Examples of polyol components other than those mentioned above include polybutadiene polyol, modified polyol of polyhydric alcohol, and hydrogenated products thereof.

[0113] Examples of modified polyols of polyhydric alcohols include those obtained by modifying raw material polyhydric alcohols by reacting them with alkylene oxides. Examples of polyhydric alcohols include trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric to octahydric alcohols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, and dipentaerythritol, as well as sucrose, glucose, mannose, fructose, methyl glucoside, and derivatives thereof; phenol polybutadiene polyols such as phenol, phloroglucin, cresol, pyrogallol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1-hydroxynaphthalene, 1,3,6,8-tetrahydroxynaphthalene, anthrol, 1,4,5,8-tetrahydroxyanthracene, and 1-hydroxypyrene; castor oil polyols; polyfunctional polyols (e.g., having 2 to 100 functional groups) such as (co)polymers of hydroxyalkyl (meth)acrylates and polyvinyl alcohol; and condensates of phenol and formaldehyde (novolaks).

[0114] The method for modifying the polyhydric alcohol is not particularly limited, but a method of adding alkylene oxide (hereinafter abbreviated as AO) is preferably used. Examples of AO include AOs having 2 to 6 carbon atoms, such as ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,3-propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide. Among these, from the viewpoints of properties and reactivity, PO, EO, and 1,2-butylene oxide are preferred, and PO and EO are more preferred. When two or more AOs are used (for example, PO and EO), the addition method may be block addition or random addition, or a combination of these.

[0115] Among these, it is preferable to use polycarbonate polyols in terms of durability, etc. Furthermore, in consideration of the impact on the environment, it is also preferable to use sebacic acid polyols obtained from plant-derived sebacic acid or castor oil polyols derived from castor oil.

[0116] The content of the polyol component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more, per 100 parts by mass of the polyurethane resin raw material components of the present invention, and is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and particularly preferably 70 parts by mass or less.

[0117] The content of the polyol component is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and particularly preferably 40 parts by mass or more, per 100 parts by mass of the polyurethane resin, and is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and particularly preferably 60 parts by mass or less.

[0118] (3) Other Raw Material Components In the present invention, in addition to the polyisocyanate component and polyol component described above, the raw material components for the polyurethane resin may contain, as necessary, a crosslinking agent, a chain extender, a curing accelerator (catalyst component), an organic solvent, etc. In addition, foaming agents, antifoaming agents, thickeners, surface conditioners, surfactants, fillers, weather resistance improvers, UV absorbers, water, dispersants, color pigments, pH adjusters, etc. may also be contained.

[0119] The chain extender is not particularly limited, but generally a diol with a relatively low molecular weight is used. Examples include petroleum-derived diols such as ethylene glycol, diethylene glycol, propanediol, butanediol, hexanediol, and PEG, and plant-derived diols such as 1,3-propanediol and 1,2-hexanediol. These diols may be used alone, or two or more may be used in combination as needed. Diamines and the like can also be used as needed. The amount of chain extender used is not particularly limited, but is generally about 1 to 5 parts by mass per 100 parts by mass of polyurethane resin.

[0120] A curing accelerator (catalyst component) can also be used. Specific examples include metal catalysts such as titanium diisopropoxybis(ethylacetoacetate), amine catalysts, and DBU catalysts. The amount of the curing accelerator used is not particularly limited, but is generally about 0.01 to 1 part by mass per 100 parts by mass of the polyurethane resin.

[0121] The organic solvent is not particularly limited, but examples thereof include polar solvents inactive to isocyanate groups, such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and organic solvents such as methyl ethyl ketone (MEK), toluene, and xylene.

[0122] The polyurethane resin preferably used as the resin constituting the surface resin layer in the present invention can be obtained by molding raw material components for a polyurethane resin, including the polyisocyanate component, the polyol component, and other raw material components used as needed, as needed, and then subjecting the molded product to treatments such as drying, heating, and curing.

[0123] The molar ratio of the polyisocyanate component to the polyol component is preferably polyisocyanate component / polyol component=0.6 / 1 to 1.8 / 1. If either the polyisocyanate component or the polyol component is too much, it becomes difficult to obtain a resin layer that exhibits durability and toughness.

[0124] The number average molecular weight of the polyurethane resin thus obtained is preferably 2000 or more, more preferably 2500 or more. There is no particular upper limit to the number average molecular weight, but it is usually 200,000,000 or less, preferably 100,000,000 or less. When the number average molecular weight of the polyurethane resin is within the above range, a resin suitable for forming a surface resin layer can be obtained.

[0125] (6) Manufacturing Method The conductive circuit panel of the present invention is manufactured by a method including a pattern forming step of forming a conductive circuit pattern on a fiber substrate to prepare a panel composite material, and a surface resin layer forming step of forming a surface resin layer on the surface of the panel composite material. If necessary, the method may also include a plated metal film forming step of forming a plated metal film on the conductive circuit pattern following the pattern forming step.

[0126] In the pattern forming step, a conductive circuit pattern is formed on the fiber substrate. The conductive circuit pattern may be formed on only one side or both sides of the fiber substrate. The conductive circuit pattern is preferably formed using an ink composition containing the above-mentioned metal.

[0127] A printing method is preferably used to form the conductive circuit pattern. A particularly preferred printing method is an inkjet printing method. The ink composition is preferably an ink composition containing metal particles. In particular, it is preferred that the ink composition contains metal particles having an average particle diameter of 1 to 200 nm. The ink composition can be a dispersion of metal particles.

[0128] In the pattern formation process, the line width or metal thickness of the conductive circuit pattern can be different between the soft and hard regions. For example, to increase the flexibility of the soft region, it is desirable to make the line width of the conductive circuit pattern in the soft region thicker than that in the hard region, or to make the amount of metal in the conductive circuit pattern in the soft region greater than that in the hard region. One method for achieving this is to use an inkjet printing method in which the ink ejection volume is increased in advance only in the soft region, or the ink ejection region is widened to increase the line width, thereby achieving the desired amount of metal and line width.

[0129] Inkjet printing methods include, but are not limited to, a method in which a line-type printing device equipped with multiple nozzles is used to form the conductive circuit pattern of the present invention by varying the amount and concentration of ink applied by each nozzle, or a scanning-type printing method in which printing is performed while adjusting the amount of metal using a single nozzle that can be moved vertically and horizontally.

[0130] In the case of screen printing, for example, two plates, one for a soft region pattern and one for a hard region pattern, are prepared and printed twice to form the conductive circuit pattern of the present invention, but the present invention is not limited to this.

[0131] The present invention relates to a method for forming a conductive circuit pattern by applying a metal-containing ink composition to the surface of a fiber substrate using a piezoelectric inkjet printing device. For example, in an inkjet printing device having an inkjet head with multiple nozzles, ink is supplied from an ink tank through an ink supply path to an inkjet head in which a piezoelectric element is arranged for each nozzle.

[0132] Next, image data corresponding to the conductive circuit pattern to be formed is created, and soft and hard regions are defined. The image data holds the target metal deposition amounts for the soft and hard regions, respectively.

[0133] Based on the image data, each area of ​​the conductive circuit pattern is matched with each nozzle of the inkjet head, and an electrical signal is sent to the piezoelectric element provided in each nozzle. The piezoelectric element receives the electrical signal and is driven to eject ink as a nozzle droplet.

[0134] Each nozzle in the multiple nozzles can be made to eject a different amount (amount of coating) by adjusting the ink ejection pressure, etc. Using this function, the ink ejection amount can be adjusted so that the target metal deposition amount set for each nozzle based on the image data is achieved, thereby ensuring that the printed conductive circuit pattern has the desired amount of metal in each region.

[0135] When using a single-nozzle inkjet printer (e.g., a scanning printer), the amount of metal in the soft and hard regions can be controlled by scanning the single nozzle vertically and horizontally while ejecting a controlled amount (or controlled droplet size).

[0136] Next, in the plating metal film forming step, which is performed as needed, a metal plating process is performed on the conductive circuit pattern obtained in the pattern forming step to form a plating metal film. The metal plating process may be either an electroplating process or an electroless plating process. Preferably, an electroless plating process is used.

[0137] The metal plating treatment can be carried out by a conventionally known method, and there are no particular limitations on the chemicals, equipment, conditions, etc. Optimal conditions can be selected depending on the type and amount of metal to be deposited.

[0138] For example, when electroless plating is performed, a conductive circuit pattern is printed on a fiber substrate with an ink composition, and then the solvent of the ink composition is removed by heating, drying, etc. Then, the fiber substrate is immersed in an electroless plating solution to perform electroless plating.

[0139] In the present invention, through the above-mentioned pattern forming process and the optional plated metal film forming process, a composite material for panels is obtained which comprises a fiber substrate, a conductive circuit pattern formed on the fiber substrate, and an optional plated metal film.

[0140] Next, in the surface resin layer forming step, a surface resin layer is formed on the surface of the obtained composite material for panels. Methods for forming a surface resin layer for each region of the composite material for panels include, for example, a method of applying a resin coating liquid to the surface of the composite material for panels, and a method of cutting out resin sheets for each region from a raw resin sheet and laminating them together, but are not limited to these, and various conventionally known methods can be used.

[0141] The resin coating solution is preferably applied to the surface of the panel composite material using an inkjet method. The solvent used in the coating solution is preferably diacetone alcohol, MEK, DPMA, or the like. The concentration of the coating solution is preferably 3.0 to 40.0% by mass. After application, the solvent is removed by heating and drying.

[0142] The soft region (folded portion) and the hard region can be separately painted by, for example, preparing a design drawing or image data of the panel to be manufactured in advance, defining the soft region and the hard region, and then inkjet printing based on that. More specifically, by setting the amount of paint to be applied for each region based on the design drawing or image data of the panel in the inkjet printer, and painting the soft region and the hard region with different amounts of paint, for example, it is possible to form a surface resin layer with different film thicknesses and bending strengths in the soft region and the hard region.

[0143] Another method for forming a surface resin layer on a panel composite is to separately prepare a raw resin sheet for the surface resin layer in advance, cut it into the shape and dimensions of each region based on the design drawing of the panel, and then attach the cut resin sheet for each region to the surface of the panel composite. It is preferable to prepare resin sheets for the soft region and resin sheets for the hard region separately in advance, each having a different film thickness and bending strength, depending on the desired panel design.

[0144] The lamination method is not particularly limited, but for example, an adhesive may first be applied to the panel composite material as needed, and then the soft region resin sheet and the hard region resin sheet, which have been cut out in advance according to the shape and dimensions based on the panel design drawings, may be laminated to the panel composite material based on the panel design drawings. Lamination can be performed using a heat press or the like. Known heat press conditions can be appropriately adopted, but the preferred conditions are a temperature of 100 to 200°C, a pressure of 0.1 to 2.0 MPa, and a time of 0.5 to 10 minutes.

[0145] The conductive circuit panel for an expandable antenna of the present invention has a soft region exhibiting low bending strength and a hard region exhibiting higher bending strength than the soft region, and is a conductive circuit panel for an expandable antenna that can be in a folded state and an expanded state, and is foldable along the soft region.

[0146] The size of the conductive circuit panel for deployable antennas of the present invention can be set appropriately depending on the application. For example, in the case of a deployable antenna mounted on an artificial satellite, a size of approximately 1.0 x 10.0 m is expected. On the other hand, for general applications such as outdoor use or disaster prevention, the size varies depending on the application, but for example, for use as a portable LED light-emitting sheet, a size of approximately 200 x 300 mm is expected. The thickness of the conductive circuit panel is not particularly limited, but is preferably approximately 0.1 to 2.0 mm.

[0147] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The methods for evaluating various physical properties in these examples are as follows.

[0148] <Method for measuring metal content> The measurement target area of ​​the conductive circuit pattern in a panel composite material composed of a fiber substrate and a conductive circuit pattern was cut out together with the fiber substrate to form a sample (approximately 30 mm x 30 mm), and its area was measured. Next, the cut-out sample was immersed in nitric acid diluted to a concentration of 50% by mass to completely dissolve the metal layer, thereby obtaining an aqueous solution containing dissolved metal. The obtained aqueous solution was diluted to a predetermined concentration, and the metal concentration in the aqueous solution was measured by atomic absorption spectrometry. The amount of metal per unit area (μg / mm) was calculated from the area of ​​the cut-out sample and the metal concentration obtained by atomic absorption spectrometry. ２ ) was calculated.

[0149] <Method for Evaluating the Bending Resistance of a Conductive Circuit Pattern> The bending resistance of the conductive circuit pattern was evaluated by the MIT bending test shown below, and the resistance increase rate was determined. A measurement target area of ​​the conductive circuit pattern in a panel composite material composed of a fiber substrate and a conductive circuit pattern was cut out together with the fiber substrate to prepare a sample (width: arbitrary, length: 200 mm). First, the resistance value of the conductive circuit pattern before the bending test was started was measured using a four-terminal method and defined as the initial resistance value. Furthermore, the increase in the resistance value of the conductive circuit pattern after the bending test was started relative to the initial resistance value was defined as the increased resistance value, and the ratio of the increased resistance value to the initial resistance value was defined as the resistance increase rate (%).

[0150] The test piece was set in an MIT testing machine (manufactured by Yuasa System Co., Ltd., product name "Desktop Bending Tester"), and a bending test was performed with a load (tension) of 250 g, bending device tip R = 0.38 mm, bending speed of 90 times / min, and bending angle of 135 degrees left and right (number of bending times: 1000 times). The resistance value of the conductive circuit pattern after the bending test was measured by the four-terminal method, and the resistance increase rate (%) was calculated based on the above definition.

[0151] <Method for Evaluating Bending Strength of Conductive Circuit Panel> The bending strength was evaluated using a bending stress measurement method based on the loop compression method (JIS L1096 method). An outline of the measurement method is shown in the schematic diagram of Figure 5. First, a test piece 5 was cut into a ribbon shape of 10 mm x 50 mm, and then both ends of the test piece 5, each 10 mm long, were clamped in a vise jig 6 to form a loop ((A) in Figure 5).

[0152] A pressure tool 7 (pressure width: 8 mm, tip angle: 85°) was set so that its center line coincided with the center line of the loop-shaped test piece 5. Next, the pressure tool 7 was vertically lowered onto the test piece 5 from the L (20 mm) position (head speed: 50 mm / min), and force was applied to the test piece 5 from the center of the loop. The pressure tool 7 was then lowered until the loop was crushed (FIG. 5 (B)). The pressure applied to the pressure tool 7 when the loop was completely crushed was measured, and this value was taken as the bending strength. This test was performed three times, and the average value was calculated. FIG. 6 shows a schematic diagram of the pressure tool. In FIG. 6, (a) is a front view of the pressure tool, (b) is a side view, and (c) is a perspective view.

[0153] <Method for measuring the amount of resin in a conductive circuit panel> A resin sheet for each region prepared for the surface resin layer (before being cut out for each region and bonded together) was cut into a 100 mm x 100 mm piece to serve as a measurement sample, the weight of which was measured using an electronic balance, and the amount of resin per unit area of ​​one resin sheet (mg / mm ２ This was then multiplied by the number of sheets (number of layers) attached to the panel composite material to determine the amount of resin per unit area of ​​the conductive circuit panel.

[0154] Example 1 A conductive circuit panel for a deployable antenna was produced as shown in Figure 1. In Figure 1, 1 is the conductive circuit panel, 2 is the hard region, and 3 is the soft region. A conductive circuit pattern was formed as shown in Figure 4.

[0155] (1) Pattern Forming Step A polyester plain weave fabric (warp: polyester textured yarn 33 dtex / 36 f, weft: polyester textured yarn 69 dtex / 150 f, weave density: warp 189 threads / 25.4 mm, weft 120 threads / 25.4 mm, thickness 90 μm) was used as the fiber substrate.

[0156] The ink composition containing metal particles was "IJ-02" (manufactured by Ishihara Chemical Co., Ltd.) This ink composition contains 35 to 45% by mass of copper particles with an average particle size of 70 nm, 50 to 60% by mass of diethylene glycol monobutyl ether, and an activator (less than 5% by mass).

[0157] The ink composition was applied to the fiber substrate using an inkjet printing device (manufactured by Seiren Co., Ltd., product name "SIT-M10", number of nozzles: 3 or more) to form a conductive circuit pattern on the fiber substrate as shown in Figure 4. The line width in the soft region was 5.0 mm, and the line width in the hard region was 1.0 mm. Note that the ink composition was formed so that it soaked into the fiber substrate and penetrated in the thickness direction of the substrate, so that it penetrated from the front surface to the back surface of the fiber substrate, and a conductive circuit pattern was essentially formed on both sides of the fiber substrate.

[0158] (2) Plated Metal Film Forming Step The fiber substrate on which the conductive circuit pattern was printed was immersed for 20 minutes in an electroless copper plating solution at 40°C containing 8.75 g / L of copper chloride dihydrate, 20 g / L of urethane resin "EDP-300" (manufactured by ADEKA Corporation), 40 mL / L of a 32 mass% aqueous sodium hydroxide solution, and 8.75 mL / L of a 37 mass% aqueous formaldehyde solution, to perform an electroless plating treatment. The substrate was then washed with water and dried in an oven at 65°C for 10 minutes. In this way, a composite material for panels was obtained in which a plated metal film was formed on the conductive circuit pattern on the fiber substrate.

[0159] The total metal amount per unit area of ​​the conductive circuit pattern in the obtained panel composite was 38.6 μg / mm in both the soft and hard regions. ２ This total metal amount is the sum of the metal amount derived from the ink composition by inkjet printing and the metal amount derived from the plated metal film formed in the plating process.

[0160] The resistance increase rate of the conductive circuit pattern in the obtained panel composite material in an MIT bending test was 410% in the soft region and 960% in the hard region.

[0161] The surface resistance of the conductive circuit pattern in the resulting composite material for panels was measured by the four-terminal method and was found to be 50 mΩ / □.

[0162] (3) Surface Resin Layer Formation Process A polyurethane resin sheet for the soft region (manufactured by Seiren Co., Ltd., polycarbonate-based polyurethane resin, thickness 25 μm) and a polyurethane resin sheet for the hard region (manufacturer: Piotek Co., Ltd., product name "123 Premier", thickness 80 μm) were prepared.

[0163] According to the design drawing of a panel having a soft region and a hard region as shown in FIG. 1, cut resin sheets for the soft region and cut resin sheets for the hard region were cut into patterns from each polyurethane resin sheet using a laser cutter.

[0164] Next, the resulting cut resin sheets for each region were bonded to both sides of the panel composite material on which the conductive circuit pattern was formed, in the arrangement shown in the panel design diagram of FIG. 1, and pressed from both sides using a heat press (soft region resin: 180 ° C, hard region resin: 130 ° C) to obtain a conductive circuit panel. For the soft region, one 25 μm thick cut resin sheet was bonded to each side of the panel composite material (total of two sheets), resulting in a total thickness of the surface resin layer of 50 μm. For the hard region, five 80 μm thick cut resin sheets were laminated to each side of the panel composite material (total of 10 sheets), resulting in a surface resin layer thickness of 800 μm. Specifically, the cut resin sheet was first bonded to the soft region and heat pressed (temperature: 180 ° C, pressure: 0.7 MPa, time: 5 minutes), and then the cut resin sheet was bonded to the hard region and heat pressed again (130 ° C, pressure: 0.7, time: 1 minute).

[0165] The resin amount in the soft region of the obtained conductive circuit panel was 0.05 mg / mm ２ The resin amount in the hard region is 3.64 mg / mm ２ It was.

[0166] The bending strength of the resulting conductive circuit panel was measured and found to be 0.04 N in the soft region and 7.6 N in the hard region.

[0167] Example 2 Using the same method as in Example 1, a conductive circuit pattern was formed on a fiber substrate to produce a composite material for a panel.

[0168] A polyurethane resin sheet for the soft region (polycarbonate polyurethane resin manufactured by Seiren Co., Ltd., thickness 25 μm) and a polyester resin sheet for the hard region (manufacturer: Toray Industries, Inc., trade name "Lumirror", thickness 30 μm) were prepared.

[0169] According to the design drawing of a panel having a soft region and a hard region as shown in Figure 1, cut resin sheets for the soft region and cut resin sheets for the hard region were cut into patterns from the resin sheets for each region using a laser cutter.

[0170] Next, the resulting cut resin sheets for each region were bonded to both sides of the panel composite material on which the conductive circuit pattern was formed, in the arrangement shown in the panel design diagram of FIG. 1, and pressed from both sides using a heat press (soft region resin: 180 ° C, hard region resin: 110 ° C) to obtain a conductive circuit panel. For the soft region, one 25 μm thick cut resin sheet was bonded to each side of the panel composite material (total of two sheets), resulting in a total thickness of the surface resin layer of 50 μm. For the hard region, one 30 μm thick cut resin sheet was bonded to each side of the panel composite material (total of two sheets), resulting in a surface resin layer thickness of 60 μm. Specifically, the cut resin sheet was first bonded to the soft region and heat pressed (temperature: 180 ° C, pressure: 0.7 MPa, time: 5 minutes), and then the cut resin sheet was bonded to the hard region and heat pressed again (110 ° C, pressure: 0.7 MPa, time: 0.5 minutes).

[0171] The obtained conductive circuit panel had a small difference in thickness between the soft and hard regions, and the overall thickness was fairly uniform. The resin amount in the soft region of the obtained conductive circuit panel was 0.05 mg / mm ２ The resin amount in the hard region is 0.14 mg / mm ２ It was.

[0172] The bending strength of the resulting conductive circuit panel was measured and found to be 0.04 N in the soft region and 0.4 N in the hard region.

[0173] The conductive circuit panel for a deployable antenna of the present invention is stored in a folded state and can be unfolded when in use to expand the transmission and reception surface. A single panel has a hard region and a soft region. The soft region has a conductive circuit pattern that gives the panel excellent flexibility while enhancing resistance to bending. By folding along this region, deterioration of the circuit and panel due to repeated folding and unfolding is prevented and shape stability is maintained when unfolded. By pre-setting the folding portions from the time of manufacture, a highly reliable deployable antenna can be obtained.

[0174] Furthermore, since the hard region increases the bending strength of the panel while allowing the conductive circuit pattern to be formed without worrying about bending resistance, advantages such as increased flexibility in the conductive pattern of the hard region, which is responsible for the main part of the antenna performance, and space saving can be obtained. The combination of such soft and hard regions makes it possible to maintain excellent antenna performance in a well-balanced manner as a whole.

[0175] The conductive circuit panel for deployable antennas of the present invention is particularly useful for aerospace applications such as artificial satellites, because it can be mounted on, for example, an artificial satellite, folded up and stored at launch, and deployed in orbit to provide a large-area transmitting and receiving surface. It is also useful for general purposes (outdoors and disaster prevention), and can be used as a portable LED light-emitting sheet by mounting an LED on the conductive circuit.

[0176] REFERENCE SIGNS LIST 1 Conductive circuit panel 2 (a) Hard region 2 (b) Hard region 3 (a) Soft region 3 (b) Soft region M Center 4 Conductive circuit pattern 5 Test piece 6 Vise jig 7 Pressurizer 8 Pressurizer pressing width (8 mm) 9 Pressurizer tip angle (85°)

Claims

1. A conductive circuit panel for an expandable antenna, which includes a panel composite material composed of a fiber base material and a conductive circuit pattern formed on the fiber base material, and which can be in a folded state and an expanded state, has a soft region exhibiting low bending strength and a hard region exhibiting higher bending strength than the soft region, and in the soft region, the resistance increase rate of the conductive circuit pattern in an MIT bending test in accordance with JIS-P8115 is 600% or less, and the conductive circuit panel for an expandable antenna is foldable along the soft region.

2. The conductive circuit panel for a deployable antenna according to claim 1, wherein the flexural strength of said soft region is 0.19 N or less and the flexural strength of said hard region is 0.2 N or more.

3. The conductive circuit panel for a deployable antenna according to claim 1, wherein the difference between the bending strength of the soft region and the bending strength of the hard region is 0.2 N or more.

4. The conductive circuit panel for an expandable antenna according to claim 1, wherein the line width of the conductive circuit pattern in the soft region is 1.0 mm or more.

5. In the soft region, the metal amount of the conductive circuit pattern is 3 to 120 μg / mm ２ 2. The conductive circuit panel for a deployable antenna according to claim 1, 6. The conductive circuit panel for a deployable antenna according to claim 1, wherein a surface resin layer is formed on at least one surface of said panel composite material in at least said hard region.

7. A conductive circuit panel for an expandable antenna as described in claim 6, wherein a surface resin layer is formed on at least one side of the panel composite material in both the soft region and the hard region, and the ratio of the amount of resin in the surface resin layer in the soft region to the amount of resin in the surface resin layer in the hard region is 1:20 or more (mass ratio).

8. The conductive circuit panel for a deployable antenna according to claim 6, wherein said surface resin layer is made of a polyurethane resin.

9. The conductive circuit panel for a deployable antenna of claim 1, wherein said panel composite material includes a plated metal film formed over the conductive circuit pattern.

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