Method of manufacturing functionally gradient material and method of manufacturing insulating spacer

Abstract

The functionally gradient material can be produced by integral casting using one mold irrespective of the kinds of the resin compositions different from each other.SOLUTION: The functionally gradient material (1') in which a plurality of resin compositions (11', 12') different from each other are joined is manufactured by including a step of casting the next resin composition (12') after the resin composition (11') previously cast into a mold reaches a predetermined viscosity.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a method for manufacturing a functionally gradient material. [Background technology]

[0002] Patent Document 1 describes a casting method in which the ratio of filler and casting resin in a mixed liquid to be injected and filled into a casting mold is continuously increased from bottom to top. Patent Document 1 describes the casting method as follows: (i) preparing a plurality of first mixed liquids with different filler sizes in a plurality of storage tanks, respectively, and mixing them to prepare a second mixed liquid containing a constant ratio of filler and casting resin, and (ii) using a control device to control the discharge amount of each of the plurality of first mixed liquids from the plurality of storage tanks, thereby continuously changing the ratio of filler and casting resin in the second mixed liquid containing a constant ratio of filler and casting resin.

[0003] Patent Document 2 describes a method for producing a functionally gradient material, which includes a step of obtaining a laminate by laminating a first resin composition and a second resin composition, and a bonding step of heating and pressurizing the laminate to bond the first resin composition and the second resin composition, in which a catalyst contained in the first resin composition and the second resin composition is used to induce dynamic covalent bonding between the first resin composition and the second resin composition in the bonding step.

[0004] Patent document 3 describes a method for manufacturing a cone-shaped insulating spacer, which includes a step of intermittently injecting two or more types of resin with different dielectric constants and a step of heat-molding the resin filled in a mold, and in the intermittent injection step, the resin is intermittently injected so that the relationship between the resin viscosity ηu of the upper layer and the resin viscosity ηl of the lower layer satisfies ηu<ηl. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-176969 [Patent Document 2] International Publication No. 2017 / 022003 [Patent Document 3] Japanese Patent Application Publication No. 2020-138486 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a demand for a method that can produce a functionally gradient material using a single mold and one-time demolding through integral casting, unlike the production methods described in Patent Documents 1 and 2. In this regard, the production method of a functionally gradient material described in Patent Document 3 has the problem that the desired functionally gradient material cannot be obtained depending on the combination of resin compositions.

[0007] One aspect of the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a novel manufacturing method and related technologies that can produce a functionally gradient material by integral casting using a single mold, regardless of the types of different resin compositions. [Means for solving the problem]

[0008] In order to solve the above problems, a method for manufacturing a functionally gradient material according to one embodiment of the present disclosure is a method for manufacturing a functionally gradient material in which a plurality of different resin compositions are bonded together, and includes a step of injecting a next resin composition into a mold after a resin composition previously poured into the mold has reached a predetermined viscosity.

[0009] Moreover, a method for manufacturing an insulating spacer according to one aspect of the present disclosure includes a step of manufacturing the functionally gradient material by the method for manufacturing a functionally gradient material according to one aspect of the present disclosure. [Effects of the Invention]

[0010] According to one aspect of the present disclosure, a novel production method can be provided that can produce a functionally gradient material by integral casting using a single mold, regardless of the types of resin compositions that differ from one another. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view illustrating an outline of a method for manufacturing a functionally gradient material according to one embodiment of the present disclosure. [Figure 2] 1 is a cross-sectional view illustrating an outline of a conventional method for manufacturing a functionally gradient material. [Figure 3] 1 is a cross-sectional view illustrating an outline of an insulating spacer 1 manufactured by a manufacturing method according to one embodiment of the present disclosure. [Figure 4] 1 is a graph of viscosity curves showing the change in viscosity over time of resin composition A sampled under each of conditions 1 to 4 in an example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] <Method of manufacturing functionally graded materials> A functionally gradient material is a material in which the composition of a material is gradually changed within a single component, thereby gradually changing the properties derived from the material and imparting a gradient to the properties. The gradient of the properties may be a stepwise gradient or a continuous gradient. An example of the properties that are gradually changed by a functionally gradient material is the dielectric constant.

[0013] As shown in FIG. 1, a method for manufacturing a functionally gradient material 1′ according to one embodiment of the present disclosure is a method for manufacturing a functionally gradient material in which a first resin composition 11′ and a second resin composition 12′, which are multiple resin compositions different from each other, are joined together, and includes a step of injecting the next second resin composition 12′ after the first resin composition 11′, which has been previously poured into a mold, reaches a predetermined viscosity.

[0014] This makes it possible to produce functionally gradient material 1' by integral casting using a single mold, regardless of the types of first resin composition 11' and second resin composition 12', which are different resin compositions, unlike the manufacturing methods of functionally gradient material described in Patent Documents 1 and 3. Furthermore, while using a known molding device, it is possible to shorten the manufacturing time and improve work safety compared to the manufacturing method of functionally gradient material described in Patent Document 2.

[0015] [Step of casting resin composition] In a method for producing a functionally gradient material according to one embodiment of the present disclosure, in the process of casting resin compositions into a single mold, it is preferable to perform a step of casting a previous resin composition into the mold, and then casting a next resin composition after the previous resin composition has reached a predetermined viscosity, multiple times in sequence, thereby making it possible to produce a functionally gradient material from multiple resin compositions.

[0016] In the process of casting a resin composition, the resin composition that is first cast into a mold may be referred to as the first resin composition, and subsequent resin compositions cast into the same mold may be referred to in turn as the second resin composition, the third resin composition, the fourth resin composition, etc. Alternatively, the stage of casting a previous resin composition into a mold may be referred to as the first casting stage, and subsequent stages of casting into the same mold may be referred to in turn as the second casting stage, the third casting stage, the fourth casting stage, etc.

[0017] The resin composition to be cast in the step of casting the resin composition contains a thermosetting resin and a filler, and may contain other additives. The resin composition increases in viscosity during the process of curing the thermosetting resin through a reaction. In the step of casting the resin composition, it is preferable to cast the next resin composition after the resin composition previously cast in the mold has reached a predetermined viscosity.

[0018] The predetermined viscosity that the first resin composition cast into the mold must reach before the second or subsequent resin compositions are cast can be appropriately designed based on the physical properties of each resin composition and the mold size based on the size of the functionally gradient material to be molded. For example, the predetermined viscosity of each resin composition is preferably 100,000 mPa·sec or higher. This prevents the next resin composition from sinking under the previously cast resin composition, even if the next resin composition has a higher specific gravity than the previous resin composition, and prevents the previously cast resin composition from floating up. Furthermore, mixing of the previously cast resin composition and the next resin composition in the mold can be prevented. Therefore, the resin compositions can be cast sequentially in the intended order, regardless of their specific gravities, to produce a functionally gradient material.

[0019] The predetermined viscosity of each resin composition is set based on the heating temperature of the mold and needs to be changed according to the heating temperature of the mold. For example, if the heating temperature of the mold is 80°C, the viscosity of the resin composition measured at 80°C is the predetermined viscosity.

[0020] The time required for a resin composition previously poured into a mold to reach a predetermined viscosity at which the next resin composition can be poured can be determined from the viscosity curve (viscosity-time curve) of each resin composition measured in advance. This makes it possible to determine the timing for pouring each subsequent resin composition into the mold after pouring the first resin composition into the mold. The time required for each resin composition to reach a predetermined viscosity can be determined by finding the viscosity curve for each resin composition.

[0021] The viscosity curve may be plotted starting from the time when the resin composition is mixed, and the time-dependent change in viscosity after the time when the minimum viscosity is reached may be graphed, and an approximate curve obtained by exponential approximation may be used as the viscosity curve. In this way, the time required for the resin composition previously poured into the mold to reach a predetermined viscosity may be predicted in advance, and the required time may be determined as the time for pouring the next resin composition.

[0022] Gel time refers to the time it takes for a resin composition to transition from a liquid state to a gel state. Gel time is measured using a Gelnorm device under specified temperature conditions. The gel time for each resin composition is measured based on the mold heating temperature and can be changed according to the mold heating temperature. For example, if the mold heating temperature is 80°C, the gel time of the resin composition measured at 80°C is the gel time measured at the specified temperature.

[0023] In the process of casting resin compositions, the next resin composition may be cast before the previous resin composition cast into the mold reaches its gel time. This increases the adhesion between the previous resin composition and the next resin composition after molding, and prevents gaps from occurring at the interface between the resin compositions after molding.

[0024] In the step of casting the resin compositions, it is preferable to perform a degassing treatment on each resin composition before casting. Furthermore, it is preferable to perform a degassing treatment on the cast resin composition as a degassing step each time a second or subsequent resin composition is cast. This allows each resin composition to be degassed, further reducing the possibility of voids being formed at the interface where the resin compositions are bonded to each other. The degassing of the resin composition may be performed by pressurized degassing or vacuum degassing.

[0025] The process of casting the resin compositions may include a first heating stage, in which the mold temperature is maintained at the time the resin compositions were cast after the final resin composition is cast, and a second heating stage, in which the mold is heated to a temperature higher than the mold temperature after the first heating stage. The process of casting and curing the final resin composition is sometimes referred to as the process of curing the resin composition. The heating time and heating temperature in the first heating stage may be designed from the perspective of shortening the production time while avoiding a rapid reaction of the resin composition cast last, but are not limited thereto and may be designed appropriately depending on the type of resin composition and the mold temperature. The mold temperature in the second heating stage may be designed appropriately depending on the size of the mold and the type of resin composition.

[0026] [Resin composition] The resin composition contains a thermosetting resin, a filler, and may contain other additives. The compositions of the resin compositions can be adjusted to have different properties by changing the type of thermosetting resin, the type of filler, and the compounding ratio of the thermosetting resin and the filler.

[0027] For example, if the amount of filler contained in each resin composition and the type of filler are changed in order to change the dielectric constant of multiple resin compositions, the difference in specific gravity between first resin composition 11' and second resin composition 12' due to the difference in the amount of filler and the difference in the type of filler will increase, which may result in a problem in which second resin composition 12' cast next sinks below first resin composition 11' cast previously into a mold (FIG. 2).One advantage of the method for producing a functionally gradient material according to one embodiment of the present disclosure is that it is possible to cast each resin composition and produce the desired functionally gradient material regardless of the difference in specific gravity between the resin compositions.

[0028] (thermosetting resin) A thermosetting resin is a resin that hardens when a base resin and a curing agent are mixed together, and may contain a catalyst that accelerates the hardening of the resin in addition to the base resin and the curing agent.

[0029] Examples of thermosetting resins include, but are not limited to, epoxy resins, phenolic resins, cyanate resins, maleimide resins, melamine resins, urea resins, silicone resins, and unsaturated polyester resins. Epoxy resins are preferred. These thermosetting resins are used as the main component, and a curing agent is selected depending on the type of main component.

[0030] When the main component of the thermosetting resin is an epoxy resin, examples of the epoxy resin include bisphenol-type epoxy resins, phenol-type epoxy resins, epoxy ether compounds in which a glycidyl group has been introduced into a polyhydric alcohol, and polycarboxylic acid ricidyl ester compounds in which a glycidyl group has been introduced into a polycarboxylic acid. Examples of the bisphenol-type epoxy resin include bisphenol A-type epoxy resins and bisphenol F-type epoxy resins. Examples of the phenol-type epoxy resin include phenol novolac-type epoxy resins and cresol novolac-type epoxy resins. Examples of the polyhydric alcohol glycidyl ether compounds include polypropylene glycol diglycidyl ether and neopentyl glycol diglycidyl ether. Examples of the polycarboxylic acid ricidyl ester compounds include phthalic acid diglycidyl ester and dimer acid diglycidyl ester.

[0031] As the curing agent for the thermosetting resin, it is preferable to use an acid anhydride-based curing agent. Examples of acid anhydride-based curing agents include aromatic carboxylic acid anhydrides, aliphatic carboxylic acid anhydrides, and polycarboxylic acid anhydrides. Examples of aromatic carboxylic acid anhydrides include phthalic anhydride, pyromellitic anhydride, and trimellitic anhydride. Examples of aliphatic carboxylic acid anhydrides include tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride. Examples of polycarboxylic acid anhydrides include polyadipic anhydride and polysebacic anhydride. Other examples of curing agents for thermosetting resins include phenol-based curing agents such as bisphenol A and novolac-type phenolic resins, amine-based curing agents such as aromatic amines, aliphatic amines, and modified amines, and polyamide-based curing agents. Depending on the type of thermosetting resin, the curing agent may contain formaldehyde.

[0032] (filling material) Examples of the filler material include inorganic fillers, such as inorganic oxides such as silica, alumina, and titanium oxide, inorganic nitrides such as aluminum nitride, boron nitride, and silicon nitride, titanates such as barium titanate, strontium titanate, and calcium titanate, silicates such as calcium silicate, and talc.

[0033] (Other additives) The resin composition may contain other additives as long as the effects of the present disclosure are not impaired. Examples of the additives include coupling agents such as silane coupling agents, titanate coupling agents, and aluminate coupling agents, as well as colorants.

[0034] <Insulating spacer manufacturing method> Fig. 3 is a cross-sectional view illustrating an outline of an insulating spacer 1 manufactured by an insulating spacer manufacturing method according to one embodiment. The insulating spacer 1 shown in Fig. 3 is used in a gas-insulated switchgear to fix a conductor 20 at a predetermined position in a sealed container.

[0035] The insulating spacer 1 is provided so as to support a conductor 20 at its center, and can be fixed so as to be sandwiched between the sealed container of the gas-insulated switchgear.

[0036] The insulating spacer has a circular shape when viewed from above, and the insulating spacer that supports the conductor by surrounding it in a circular shape is sometimes formed by centrifuging a mold. When manufacturing the insulating spacer by centrifugal separation, resin compositions may be mixed together during the centrifugation, which may make it difficult to manufacture the insulating spacer using a functionally gradient material.

[0037] However, according to one embodiment of the method for producing an insulating spacer, a first casting step of casting a first resin composition 11, a second casting step of casting a second resin composition 12, and a third casting step of casting a third resin composition 13 are performed, thereby molding an insulating spacer 1 formed from a three-phase functionally gradient material as shown in FIG. 3 . The mold for the insulating spacer may be a mold in which the first resin composition 11 shown in FIG. 3 is placed on the lower side and placed in a thermostatic chamber, or the mold may be turned upside down to be a mold in which the third resin composition 13 shown in FIG. 3 is placed on the lower side. When the mold is turned upside down, the first resin composition 11 is cast at the position of the third resin composition 13 shown in FIG. 3 . The resin compositions may be cast into the mold for the insulating spacer by, for example, placing a supply nozzle over a casting port (not shown) provided in the mold and sequentially supplying the resin compositions from the supply nozzle.

[0038] The insulating spacer 1 can be molded so that the second resin composition 12 does not sink into the first resin composition 11 located in the lower layer, and the third resin composition 13 does not sink into the second resin composition 12, even if the difference in specific gravity due to the inclusion of a filler material increases in that order. Therefore, a method for manufacturing an insulating spacer according to one embodiment and an insulating spacer manufactured by this method are also within the scope of the present disclosure. The insulating spacer 1 shown in FIG. 3 is merely an example, and an insulating spacer having, for example, four or more layers of resin compositions is also within the scope of the present disclosure.

[0039] 〔summary〕 The method for producing a functionally gradient material according to aspect 1 of the present disclosure is a method for producing a functionally gradient material in which a plurality of different resin compositions are bonded together, and includes a step of pouring a next resin composition into a mold after a resin composition previously poured into the mold has reached a predetermined viscosity.

[0040] In the method for producing a functionally gradient material according to Aspect 2 of the present disclosure, in Aspect 1, the predetermined viscosity is preferably 100,000 mPa·sec or more.

[0041] In the method for producing a functionally gradient material according to aspect 3 of the present disclosure, in the above aspect 1 or 2, the next resin composition may be cast before the gel time of the previously cast resin composition.

[0042] The method for producing a functionally gradient material according to Aspect 4 of the present disclosure may be any of Aspects 1 to 3, in which the next resin composition is poured into a mold and then degassed.

[0043] The method for producing a functionally gradient material according to aspect 5 of the present disclosure is, in any one of aspects 1 to 4 above, preferably by determining the time for pouring the next resin composition into the mold from the viscosity curve of the resin composition that is poured first into the mold.

[0044] A manufacturing method of a functionally gradient material according to aspect 6 of the present disclosure is any one of aspects 1 to 5 above, wherein each of the resin compositions contains a thermosetting resin and a filler material, and the specific gravity of the resin composition to be cast next may be greater than that of the resin composition to be cast first, and the filler material may be selected from silica, alumina, titanium oxide, barium titanate, strontium titanate, and calcium titanate.

[0045] A method for producing an insulating spacer according to a seventh aspect of the present disclosure includes a step of producing a functionally gradient material by the method for producing a functionally gradient material according to any one of the first to sixth aspects.

[0046] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. [Example]

[0047] Examples of the present disclosure are described below. Two resin compositions with different specific gravities were blended, and the time conditions from when the lower layer was cast until the upper layer was cast, as well as the degassing conditions after the resin composition for the upper layer was cast into a mold, were changed to mold a functionally gradient material having two layers of resin compositions with different specific gravities, and the state of each layer was evaluated.

[0048] [1] Functionally gradient materials The materials and compounding ratios of the resin composition for molding the functionally gradient material are as shown in Table 1 below.

[0049] [Table 1]

[0050] Bisphenol A epoxy resin: EPOXY RESIN CY225, manufactured by Nagase ChemteX Corporation Liquid anhydride hardener: HARDENER HY925, manufactured by Nagase ChemteX Corporation Silica: Silica Powder HHH, manufactured by Fumitec Co., Ltd. Alumina: Show Filler FA-4, manufactured by Resonac Co., Ltd. Coloring agent: COLORING PASTE DW06, manufactured by Nagase ChemteX Corporation

[0051] The specific gravity of resin compositions A and B shown in Table 1 was measured in accordance with JIS K6911 (5.28). t The resin composition was poured into a mold and cured to obtain a cured product. The cured product was removed from the mold and cut out at any point of the cured product, excluding the top and bottom ends, to prepare a test piece measuring 10 mm x 20 mm, and the specific gravity was measured using the test piece.

[0052] [2] Molding of functionally gradient materials 150mm x 150mm x 10mm t A mold was prepared, and the lower layer resin composition and the second resin composition were poured into the mold to form a functionally gradient material including the lower layer resin composition and the upper layer resin composition. The molding of the functionally gradient material was carried out according to the following procedures (1) to (6). (1) Material preparation and preheating The materials and molds used to prepare the lower layer resin composition and upper layer resin composition were preheated to 80°C. (2) Formulation and Casting of the Lower Layer Resin Composition Using the materials preheated to 80°C in step (1), the lower layer resin composition was compounded into a beaker and vacuum degassed for 5 minutes at 80°C. Subsequently, the lower layer resin composition was poured into a mold preheated to 80°C, and then the mold and the composition were further vacuum degassed for 10 minutes at 80°C. (3) Heat curing of the lower layer resin composition The lower layer resin composition that had been vacuum degassed together with the mold in step (2) was heated in a thermostatic chamber at 80° C. The heat curing time in the thermostatic chamber was changed to conditions 1 to 4 shown in Table 2 below. (4) Blending and Casting of the Upper Layer Resin Composition The upper layer resin composition was blended using the material preheated to 80°C in step (1), and the mixture was vacuum degassed at 80°C for 5 minutes. The upper layer resin composition was then poured into a mold preheated to 80°C, and the mold was further vacuum degassed at 80°C for 10 or 15 minutes. This resulted in a functionally gradient material being poured into the mold, with the upper layer resin composition as the upper layer above the lower layer resin composition. (5) Heat curing conditions for functionally graded materials The functionally gradient material that had been vacuum degassed together with the mold in step (4) was transferred into a thermostatic chamber, and the temperature in the thermostatic chamber was maintained at 80°C for 6 hours.The temperature was then raised from 80°C to 130°C over 1 hour, and the functionally gradient material was then heated by maintaining the temperature at 130°C for 10 hours. (6) Demolding of Functionally Graded Materials The thermostatic chamber is returned to room temperature, the mold is allowed to cool naturally, and then a 10 mm thick plate is removed from the mold. t The molded functionally gradient material was then taken out.

[0053] Molding of functionally gradient materials according to the above steps (1) to (6) was carried out four times under different conditions 1 to 4 shown in Table 2. Table 2 shows the lower layer resin compositions and upper layer resin compositions used under conditions 1 to 4, as well as the heat curing time in step (3) and the vacuum degassing time in step (4).

[0054] [Table 2]

[0055] The evaluation results of the functionally gradient materials obtained by casting under conditions 1 to 4 are shown in FIGS.

[0056] In the functionally gradient material obtained under condition 1, it was confirmed that there was no boundary between resin composition A and resin composition B poured onto it, and that the two compositions were in a state where they were mixed together overall (Comparative Example 1).

[0057] In the functionally gradient material obtained under condition 2, it was confirmed that resin composition B, which was poured onto the upper layer of resin composition A, sank to the bottom, and resin composition A wrapped around to the top (Comparative Example 2).

[0058] In the functionally gradient material obtained under condition 3, it was confirmed that resin composition B, which was poured onto the upper layer of resin composition A, did not sink to the bottom, and that resin composition B hardened on top of resin composition A (Example 1).

[0059] In the functionally gradient material obtained under condition 4, it was confirmed that resin composition B, which was poured onto the upper layer of resin composition A, did not sink to the bottom, and that resin composition B hardened on top of resin composition A (Example 2).

[0060] From the above evaluation results, it was confirmed that the expected casting resin could be formed under the condition that the heat curing time of the lower layer resin composition was set to 4 hours or more.

[0061] [3] Viscosity evaluation Table 3 below shows the difference in viscosity of resin composition A immediately before casting resin composition B for the upper layer due to differences in the heat curing time in step (3) under conditions 1 to 4. The viscosity of resin composition A shown in Table 3 was measured using a sample of resin composition A, the layer resin composition, sampled in step (2) above after vacuum degassing the resin composition A in a beaker at 80°C for 5 minutes. The viscosity was measured using a Brookfield viscometer (B-type rotational viscometer) DV2T at a rotation speed of 2 rpm in an atmosphere of 80°C.

[0062] [Table 3]

[0063] As shown in Table 3, under conditions 3 and 4, which allowed resin composition B to be poured onto the upper layer of resin composition A without sinking to the bottom, the viscosity of resin composition A immediately before pouring upper layer resin composition B was 100,000 mPa·sec or higher. This suggests that by setting the viscosity of the lower layer resin composition to 100,000 mPa·sec or higher, it is possible to form a functionally gradient material having upper and lower layers, preventing the upper layer resin composition from settling even if the lower layer resin composition has a lower density than the upper layer resin composition.

[0064] Figure 4 shows a graph of the viscosity curves illustrating the change in viscosity over time for resin composition A sampled under each of the above conditions 1 to 4. From the graph in Figure 4, it can be seen that for each sample whose viscosity reached 5000 mPa·s approximately 70 minutes after casting of resin composition A, there was little variation in viscosity for each sample, and each sample thickened at a substantially constant rate. This suggests that controlling the heating conditions after casting the lower-layer resin composition can achieve a stable increase in viscosity, allowing the timing for casting the upper-layer resin composition to be designed. Furthermore, for example, by graphing the viscosity change after the minimum viscosity of each sample shown in Figure 4 and drawing an exponential approximation curve, it is possible to design the timing for casting the upper-layer resin composition over a lower-layer resin composition whose viscosity has increased to a level that makes it difficult to measure viscosity before the gel time.

[0065] [4] Gel time measurement The gel time of a sample of resin composition A measured in accordance with DIN 16945 in a gelnorm apparatus at 80° C. is approximately 300 minutes. [Industrial Applicability]

[0066] The present disclosure can be used to manufacture a functionally gradient material, and can be used, for example, to manufacture an insulating spacer using the functionally gradient material. [Explanation of symbols]

[0067] 1 insulating spacer 1' functionally graded material 11, 11' First resin composition 12, 12' Second resin composition 13 Third resin composition 20 Conductors

Claims

1. A method for producing a functionally gradient material in which a plurality of different resin compositions are bonded together, comprising: A method for producing a functionally gradient material, comprising the step of pouring a next resin composition into a mold after a resin composition previously poured into the mold has reached a predetermined viscosity.

2. The method for producing a functionally gradient material according to claim 1, wherein the predetermined viscosity is 100,000 mPa·sec or more.

3. 2. The method for producing a functionally gradient material according to claim 1, wherein the next resin composition is cast before the gel time of the previously cast resin composition.

4. 2. The method for producing a functionally gradient material according to claim 1, wherein the subsequent resin composition is poured into a mold and then degassed.

5. 2. The method for producing a functionally gradient material according to claim 1, wherein the time for pouring the next resin composition into the mold is determined from the viscosity curve of the resin composition that is poured first into the mold.

6. Each of the resin compositions contains a thermosetting resin and a filler material, and the resin composition to be cast next has a larger specific gravity than the resin composition to be cast first; The method for producing a functionally gradient material according to claim 1 , wherein the filler material is selected from the group consisting of silica, alumina, titanium oxide, barium titanate, strontium titanate, and calcium titanate.

7. A method for manufacturing an insulating spacer, comprising the step of manufacturing a functionally gradient material by the method for manufacturing a functionally gradient material according to any one of claims 1 to 6.

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