Resin mixture and substrate

Abstract

In environments such as outer space and high altitudes, where human exposure to radiation is a concern, the extreme temperature fluctuations pose a risk. Therefore, when conventional radiation shielding resin compositions are applied to substrates such as alloys, there was a concern that the difference in expansion rates between the substrate and the radiation shielding resin composition could cause the composition to peel off. Consequently, there was a need for a resin composition that could shield against radiation and would not peel off even when applied to substrates such as alloys used in environments with large temperature fluctuations. [Solution] A resin mixture containing resin, cerium oxide, and silica, wherein the cerium oxide content in the resin composition obtained by curing the resin mixture is set to 39% by volume or more.

Description

Technical Field

[0001] The present invention relates to a resin mixture and a substrate.

Background Art

[0002] In recent years, the aerospace industry has been growing continuously, and the opportunities for humans to conduct activities in the space environment have also increased. In order for humans to conduct activities safely in the space environment, it is important to shield radiation such as X-rays flying through space and reduce the exposure dose, and the development of materials that can reduce the exposure dose in such space has been underway.

[0003] Patent Document 1 proposes a radiation-shieldable resin composition containing a binder resin and a shielding material.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, spaces such as space and high-altitude space where radiation exposure to the human body becomes a problem are harsh environments with large temperature changes. When the radiation-shielding resin composition proposed in Patent Document 1 is used for coating on a substrate such as an alloy, there is a concern that the radiation-shielding resin composition may peel off due to the difference in the expansion rate between the substrate and the radiation-shielding resin composition.

[0006] Therefore, there has been a demand for a resin composition that can shield radiation and does not peel off even when used for coating on a substrate such as an alloy used in an environment with large temperature changes.

Means for Solving the Problems

[0007] A means for solving the above problem is a resin mixture containing a resin, cerium oxide, and silica, wherein the content of cerium oxide in the resin composition obtained by curing the resin mixture is 39% by volume or more. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition that can shield against radiation and does not peel off even when used in an environment with large temperature fluctuations. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view of the resin composition of this embodiment. [Modes for carrying out the invention]

[0010] [Embodiment] The resin mixture material according to this embodiment contains a resin, cerium oxide, and silica. By applying such a resin mixture material to an object and curing it, a resin composition 1 containing resin 2, cerium oxide 3, and silica 4 is formed on the object as shown in Figure 1.

[0011] We discovered that by blending cerium oxide and silica together in a resin mixture, it is possible to achieve high levels of cerium oxide and silica in the resin. Specifically, by using such a resin mixture, the cured resin composition on the object can contain 39% or more by volume of cerium oxide. Furthermore, the total amount of cerium oxide and silica in the resin composition can be 57% or more by volume.

[0012] The reason is that Ce in cerium oxide 3+ However, the O in the Si-O-Si bond in glass 2- It is thought that this is because the affinity between the particles and the resin increases through interaction.

[0013] These resin mixtures can be applied to substrates such as alloys used in objects that fly in the atmosphere and in outer space, such as airplanes and satellites. By forming a resin composition containing cerium oxide and silica with a film thickness of 1 mm or more on the surface of the object (substrate), radiation can be shielded, and peeling can be suppressed even when used in environments with large temperature fluctuations.

[0014] This embodiment will now be described in detail.

[0015] (resin) The resin mixture contains cerium oxide and silica, as well as a resin as a binder. Any resin can be used, such as thermoplastic resins, thermosetting resins, UV-curing resins, or two-component curing resins, as long as it satisfies the desired physical properties, including viscosity. These resins may be used individually or in combination of two or more.

[0016] (Cerium oxide) The resin mixture contains cerium oxide, which functions as a radiation shielding material.

[0017] In a resin composition formed by curing a resin mixture, the cerium oxide content is preferably 39% by volume or more. Within this range, sufficient radiation shielding performance can be obtained by applying the resin composition to an object. Furthermore, from the viewpoint of radiation shielding performance, it is more preferable that the cerium oxide content in the resin composition be 54% by volume or more.

[0018] Virgin cerium oxide raw materials, recycled materials, etc., can be used. These cerium oxide raw materials may be used individually or in combination of two or more. The particle size of these cerium oxide particles is preferably between 2.0 μm and 9.0 μm.

[0019] (silica) The resin mixture contains silica as an inorganic filler. As the silica, any of spherical silica, crushed silica, etc. can be used as long as it satisfies the desired properties such as the filling rate into the resin. These silicas may be used alone or in combination of two or more. The particle size of these silicas is preferably in the range of 0.1 μm or more and 4.0 μm or less.

[0020] In the resin composition obtained by curing the resin mixture, it is preferable that the total content of cerium oxide and silica is 57% by volume or more. Within this range, a sufficient linear expansion coefficient can be obtained. Further, from the viewpoint of the linear expansion coefficient, in the resin composition, it is more preferable that the total content of cerium oxide and silica is 67% by volume or more.

[0021] (Additive) The resin mixture may contain an additive as required in addition to the resin, cerium oxide and silica. As the additive, any of a curing accelerator, an antioxidant, a flame retardant, a silane coupling agent, a plasticizer, etc. can be used. These additives may be used alone or in combination of two or more.

Examples

[0022] Hereinafter, specific examples and comparative examples will be described.

[0023] [Manufacturing method] The resin, cerium oxide, silica and additive in the resin composition were weighed so as to have the desired composition.

[0024] The resin was prepared using an alicyclic epoxy (Daicel Corporation's "Celoxide 8010") as the main component, which has excellent weather resistance and relatively low viscosity, and mixed with an equivalent amount of curing agent (Shin Nippon Rika Co., Ltd.'s "Ricacid MH-700G"). Subsequently, cerium oxide (Treibacher Industries AG's "FG50") and silica (Tokuyama Corporation's "Sunseal") were mixed with the resin using a planetary rotary stirrer until the materials were homogenized, obtaining a resin mixture. This resin mixture (resin mixture material) was dropped onto a 15 cm square flat mold with a 1 mm thick spacer placed on top, and then sandwiched between two more 15 cm square flat molds. This was heated in an electric furnace at 120°C for 1 hour, and then further heated at 150°C for 3 hours to fully cure, obtaining a 15 cm square, 1 mm thick resin composition film.

[0025] [Evaluation Method] (Composition ratio) The obtained resin composition film was cut into 5 cm squares using a cutter to prepare samples for measuring the mixing ratio. The mixing ratio was measured using an X-ray fluorescence analyzer (XRF) (manufactured by Hitachi High-Tech Science Corporation). Elemental mapping was performed on the surface of the prepared measurement samples using XRF to identify the locations of resin, cerium oxide, and silica. Subsequently, the area of ​​each of the resin, cerium oxide, and silica was calculated from the obtained map. This operation was performed in four arbitrary ranges on the surface of the measurement sample, and the areas of resin, cerium oxide, and silica obtained in each range were averaged to obtain the average area. The ratio of the average area of ​​resin to the total area of ​​the map was defined as the volume % of resin, the average area of ​​cerium oxide to the total area of ​​the map was defined as the volume % of cerium oxide, and the average area of ​​silica to the total area of ​​the map was defined as the volume % of silica.

[0026] (Radiation shielding performance) The obtained resin composition film was cut into 5 cm squares using a cutter to prepare samples for measuring radiation shielding performance. Radiation shielding performance was measured at a tube voltage of 100 kV according to JIS Z 4501:2011 and evaluated in terms of lead equivalent (mmPb).

[0027] For example, the lead equivalent of radiation protective clothing used in hospital X-ray rooms is known to be between 0.25 mmPb and 0.35 mmPb, and it is considered that any amount above 0.25 mmPb is sufficient for radiation protective clothing.

[0028] Based on this, radiation shielding performance of 0.35 mmPb or higher was evaluated as A, i.e., excellent; performance between 0.25 mmPb and less than 0.35 mmPb was evaluated as B, i.e., good; and performance below 0.25 mmPb was evaluated as C, i.e., poor.

[0029] (Coefficient of linear expansion) The obtained resin composition film was cut into 1 cm squares using a cutter to prepare samples for measurement of the coefficient of linear expansion. The coefficient of linear expansion was measured using a thermomechanical analyzer (TMA) (manufactured by TA Instruments). The temperature was raised from 0°C to 150°C at a rate of 10°C / min, held at 150°C for 5 minutes, and then cooled from 150°C to 0°C at a rate of 10°C / min. This cycle was repeated three times, and the coefficient of linear expansion was calculated from the temperature profiles of the second and third cycles.

[0030] Aluminum alloys used in structural materials for aircraft and rockets are known to have a coefficient of thermal expansion of approximately 24 ppm / K. When the resin composition according to the present invention is applied to this aluminum alloy as a base material, it is believed that the smaller the difference in the coefficients of thermal expansion between the aluminum alloy base material and the resin composition, the less likely the resin composition is to break down due to temperature changes.

[0031] Based on this, samples with a coefficient of thermal expansion of 24 ppm / K or less were rated A, i.e., excellent; samples with a coefficient of thermal expansion greater than 24 ppm / K but 31 ppm / K or less were rated B, i.e., good; and samples with a coefficient of thermal expansion greater than 31 ppm / K were rated C, i.e., poor.

[0032] [Evaluation Results] (Example 1) 3.8 g of epoxy resin, 6.2 g of curing agent, 149.7 g of cerium oxide, and 8.8 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0033] XRF analysis of the obtained resin composition revealed that the resin was 25% by volume, cerium oxide 63% by volume, silica 12% by volume, and the total of cerium oxide and silica was 75% by volume.

[0034] When the radiation shielding performance was measured, an excellent radiation shielding performance of 0.41 mmPb was obtained, and the evaluation was A.

[0035] Furthermore, the coefficient of thermal expansion measured by TMA was 18.3 ppm / K, which is an excellently small coefficient of thermal expansion, and the evaluation was A.

[0036] (Example 2) 3.8 g of epoxy resin, 6.2 g of curing agent, 97.2 g of cerium oxide, and 7.2 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0037] XRF analysis of the obtained resin composition revealed that the resin was 33% by volume, cerium oxide 54% by volume, silica 13% by volume, and the total of cerium oxide and silica was 67% by volume.

[0038] When the radiation shielding performance was measured, an excellent radiation shielding performance of 0.35 mmPb was obtained, and the evaluation was A.

[0039] Furthermore, the coefficient of thermal expansion measured by TMA was 23.8 ppm / K, which is an excellently small coefficient of thermal expansion, and the evaluation was A.

[0040] (Example 3) 3.8 g of epoxy resin, 6.2 g of curing agent, 85.8 g of cerium oxide, and 6.1 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0041] XRF analysis of the obtained resin composition revealed that the resin was 36% by volume, cerium oxide 52% by volume, silica 12% by volume, and the total of cerium oxide and silica was 64% by volume.

[0042] When the radiation shielding performance was measured, a sufficient radiation shielding performance of 0.34 mmPb was obtained, and the evaluation was B.

[0043] Furthermore, the coefficient of thermal expansion measured by TMA was 25.8 ppm / K, which is a sufficiently small coefficient of thermal expansion, and the evaluation was B.

[0044] (Example 4) 3.8 g of epoxy resin, 6.2 g of curing agent, 93.4 g of cerium oxide, and 5.2 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0045] XRF analysis of the obtained resin composition revealed that the resin was 35% by volume, cerium oxide 55% by volume, silica 10% by volume, and the total of cerium oxide and silica was 65% by volume.

[0046] When the radiation shielding performance was measured, an excellent radiation shielding performance of 0.36 mmPb was obtained, and the evaluation was A.

[0047] Furthermore, the coefficient of thermal expansion measured by TMA was 25.2 ppm / K, which is a sufficiently small coefficient of thermal expansion, and the evaluation was B.

[0048] (Example 5) 3.8 g of epoxy resin, 6.2 g of curing agent, 89.1 g of cerium oxide, and 15.3 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0049] XRF analysis of the obtained resin composition revealed that the resin was 30% by volume, cerium oxide 45% by volume, silica 25% by volume, and the total of cerium oxide and silica was 70% by volume.

[0050] When the radiation shielding performance was measured, a sufficient radiation shielding performance of 0.29 mmPb was obtained, and the evaluation was B.

[0051] Furthermore, the coefficient of thermal expansion measured by TMA was 21.6 ppm / K, which is an excellently small coefficient of thermal expansion, and the evaluation was A.

[0052] (Example 6) 3.8 g of epoxy resin, 6.2 g of curing agent, 53.9 g of cerium oxide, and 7.7 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0053] XRF analysis of the obtained resin composition revealed that the resin was 43% by volume, cerium oxide 39% by volume, silica 18% by volume, and the total of cerium oxide and silica was 57% by volume.

[0054] When the radiation shielding performance was measured, a sufficient level of 0.25 mmPb was obtained, resulting in a rating of B.

[0055] Furthermore, the coefficient of thermal expansion measured by TMA was 30.6 ppm / K, which is a sufficiently small coefficient of thermal expansion, and the evaluation was B.

[0056] (Comparative Example 1) 3.8 g of epoxy resin, 6.2 g of curing agent, 48.9 g of cerium oxide, and 7.3 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0057] XRF analysis of the obtained resin composition revealed that the resin was 45% by volume, cerium oxide 37% by volume, silica 18% by volume, and the total of cerium oxide and silica was 55% by volume.

[0058] When the radiation shielding performance was measured, it was found to be 0.24 mmPb, which is insufficient, and the evaluation was C.

[0059] Furthermore, the coefficient of thermal expansion measured by TMA was 32.0 ppm / K, which was not sufficiently small, and the evaluation was C.

[0060] (Comparative Example 2) 3.8 g of epoxy resin, 6.2 g of curing agent, 43.2 g of cerium oxide, and 1.7 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0061] XRF analysis of the obtained resin composition revealed that the resin was 55% by volume, cerium oxide 40% by volume, silica 5% by volume, and the total of cerium oxide and silica was 45% by volume.

[0062] When the radiation shielding performance was measured, a sufficient radiation shielding performance of 0.26 mmPb was obtained, and the evaluation was B.

[0063] However, the coefficient of thermal expansion measured by TMA was 39.0 ppm / K, which was not small enough, and the evaluation was C.

[0064] (Comparative Example 3) 3.8 g of epoxy resin, 6.2 g of curing agent, 52.0 g of cerium oxide, and 11.5 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0065] XRF analysis of the obtained resin composition revealed that the resin was 40% by volume, cerium oxide 35% by volume, silica 25% by volume, and the total of cerium oxide and silica was 60% by volume.

[0066] When the radiation shielding performance was measured, it was found to be 0.23 mmPb, which is insufficient, and the evaluation was C.

[0067] The coefficient of thermal expansion measured by TMA was 28.5 ppm / K, which is a sufficiently small coefficient of thermal expansion, and the evaluation was B.

[0068] (Comparative Example 4) 3.8 g of epoxy resin, 6.2 g of curing agent, 32.4 g of cerium oxide, and 5.0 g of silica were weighed out, and a resin composition film was obtained using the manufacturing method described above.

[0069] XRF analysis of the obtained resin composition revealed that the resin was 55% by volume, cerium oxide 30% by volume, silica 15% by volume, and the total of cerium oxide and silica was 45% by volume.

[0070] When the radiation shielding performance was measured, it was found to be 0.20 mmPb, which is insufficient, and the evaluation was C.

[0071] Furthermore, the coefficient of thermal expansion measured by TMA was 38.9 ppm / K, which was not sufficiently small, and the evaluation was C.

[0072] Table 1 summarizes the blending ratios and evaluation results of each material in Examples 1 to 6 and Comparative Examples 1 to 4.

[0073] [Table 1]

[0074] The present invention is not limited in any way to the embodiments and examples described above.

[0075] The resin composition of the present invention can be used for purposes other than radiation shielding members, such as ultraviolet shielding members and heat insulating paints.

[0076] <Summary of Embodiments> The disclosures herein include at least the following components:

[0077] (Item 1) A resin mixture containing resin, cerium oxide, and silica, The cerium oxide content in the resin composition obtained by curing the resin mixture is 39% by volume or more. A resin mixture characterized by the following features.

[0078] (Item 2) The total content of cerium oxide and silica in the resin composition is 57% by volume or more. The resin mixture described in item 1, characterized by the features described herein.

[0079] (Item 3) The cerium oxide content in the resin composition is 54% by volume or more. A resin mixture according to item 1 or 2, characterized by the features described above.

[0080] (Item 4) The total content of cerium oxide and silica in the resin composition is 67% by volume or more. The resin composition according to item 2, characterized in that it is a resin composition according to item 2.

[0081] (Item 5) A substrate on which the resin composition described in any one of items 1 to 4 is formed.

[0082] (Item 6) The substrate according to item 5, characterized in that the resin composition formed on the substrate has a film thickness of 1 mm or more.

Claims

1. A resin mixture containing resin, cerium oxide, and silica, The content of cerium oxide in the resin composition obtained by curing the resin mixture is 39% by volume or more. A resin mixture characterized by the following features.

2. The total content of cerium oxide and silica in the resin composition is 57% by volume or more. The resin mixture according to feature 1.

3. The cerium oxide content in the resin composition is 54% by volume or more. The resin mixture according to feature 1.

4. The total content of cerium oxide and silica in the resin composition is 67% by volume or more. The resin composition according to claim 2, characterized by the features described above.

5. A substrate on which the resin composition according to claim 1 is formed.

6. The substrate according to claim 5, characterized in that the resin composition formed on the substrate has a film thickness of 1 mm or more.

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