JP2008207523A - Panel for x-ray cassette - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an FRP sandwich panel having a uniform distribution of X-ray transmission performance in a panel surface while having a partially different thickness, and to provide a method of manufacturing the sandwich panel at a low cost. <P>SOLUTION: The panel for an X-ray cassette has a sandwich structure comprising a skin of a fiber-reinforced plastic containing a carbon fiber and a core of a resin foamed body, the ratio of the maximum thickness of the panel to the minimum thickness thereof is in the range from 1.5 to 3.0, the ratio of the maximum thickness of the skin to the minimum thickness thereof is in the range from 1.0 to 1.3, the product (kg/m<SP>2</SP>) of the thickness of the core at an arbitral position of the panel and an apparent density of the core is 0.8 to 1.2 times the product (kg/m<SP>2</SP>) of the thickness of the core at another arbitral position of the panel and the apparent density of the core. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is an X-ray cassette used for medical X-ray diagnosis, which requires light weight, high rigidity, and X-ray permeability, and can be used as a part of a casing that is fastened to other parts. The present invention relates to a fiber reinforced plastic (hereinafter abbreviated as FRP) sandwich panel.

Carbon fiber reinforced plastic that is lightweight, highly rigid, and excellent in X-ray permeability is used for the panels that make up X-ray cassettes that are used for medical X-ray diagnosis and contain X-ray photographic films and stimulable phosphor sheets. A panel made of (hereinafter abbreviated as CFRP) is often used. Recently, in order to further enhance the X-ray permeability, sharpen the X-ray diagnostic image and reduce the amount of X-ray exposure to the human body, the skin is CFRP in a structure in which the core is sandwiched by the skin, so-called sandwich structure. A panel having a core formed of a low-density foam has been studied (for example, see Patent Document 1). In any of the above panel structures, in order to obtain a uniform X-ray transmission distribution within the plane of the panel, it is common to use a flat plate structure having a uniform thickness for the cross-sectional shape of the panel.
However, when actually used as a cassette, in order to avoid interference with frame-shaped parts on the outer periphery of the panel or image recording sheet parts inserted in the cassette, the panel is not limited to a flat plate shape. It may be preferable to bend into a flange shape. In addition, it is very effective to locally increase the thickness of the panel in order to increase the surface rigidity of the panel, and it may be preferable to provide different thicknesses in the plane of the panel in order to improve the design. In such a case, it is important to ensure uniform X-ray transparency in the panel surface while obtaining desired panel shapes having different thicknesses in the panel surface. Moreover, in order to ensure uniform X-ray transparency, it is preferable that the material in the panel is also seamless and the structure is uniform. It is also important to produce panel shapes having different thicknesses at a low cost. In general, when manufacturing FRP sandwich panels with different thicknesses, cores with different thicknesses are prepared in advance by machining or thermal compression, and uncured FRP skins are placed on both sides of the core. Molding methods such as resin transfer molding (hereinafter abbreviated as RTM), in which the reinforcing fiber is impregnated with thermosetting resin in the mold by molding in an autoclave or by placing a skin of reinforcing fiber not impregnated with resin Is used. Alternatively, a method may be used in which a core having a partially different thickness and an FRP skin conforming to the surface irregularity shape of the core are separately formed and the skin and the core are bonded. For example, Patent Document 2 proposes a technique related to integral molding of a sandwich panel using a foamed resin core, but the panel shape is a flat plate structure having a uniform thickness. On the other hand, Patent Document 3 proposes a technique related to a sandwich panel having cross-sectional shapes with different thicknesses. However, there is a problem that uniform X-ray transmission is difficult to obtain and a large cost is required for molding. is there.
JP 2005-313613 A JP 59-176036 A JP 2005-219349 A

  An object of the present invention is to provide an X-ray cassette panel having a uniform X-ray transmission distribution in the panel surface while having a partially different thickness, and its low cost, which has not been sufficiently studied in the prior art. An object of the present invention is to provide a simple manufacturing method.

In order to achieve the above object, the X-ray cassette panel of the present invention has the following configuration. That is, an X-ray cassette panel having a sandwich structure in which a skin is a carbon fiber reinforced plastic and a core is a resin foam, and the ratio of the maximum thickness to the minimum thickness is 1.5 to 3.0. And the skin has a ratio of the maximum thickness to the minimum thickness in the range of 1.0 to 1.3, and the product of the core thickness and the apparent core density at an arbitrary part of the panel (kg) / M ² ) is in the range of 0.8 to 1.2 times the product (kg / m ² ) of the core thickness and the apparent core density at any other part of the panel. Panel.

  Moreover, in order to achieve the said objective, the manufacturing method of the panel for X-ray cassettes of this invention has the following structure. That is, a prepreg containing carbon fibers is formed on both the front and back surfaces of a resin foam sheet to form a preform, and an upper mold and a lower mold in which concave and convex cavities are formed are opened, and the preform is formed between them. After placing the upper mold and the lower mold, the panel after molding has a minimum thickness of 0.2 to 0.6 times the thickness of the preform, and its maximum thickness is the thickness of the preform. An X-ray cassette characterized by being molded within a range of 0.3 to 0.9 times and a ratio of the maximum thickness and the minimum thickness of the panel within a range of 1.5 to 3.0 It is a manufacturing method of the panel.

  According to the X-ray cassette panel of the present invention, while being a sandwich panel having partially different thicknesses, avoiding interference with other parts, facilitating fitting, and having high rigidity in a plane. Excellent X-ray transparency and the same level of X-ray transparency can be obtained at any position on the panel surface. Therefore, the degree of freedom of design is increased when the panel is mounted on the X-ray cassette. Further, according to the method for manufacturing an X-ray cassette panel of the present invention, a panel having a partially different thickness and suitable for an X-ray cassette is manufactured at a cost equivalent to that of a conventional flat panel having a uniform thickness. It is possible.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the absolute value of the amount of X-ray transmission is almost inversely proportional to the product of the thickness and density of the transmission material when transmitting through a structure made of the same material. Focusing on this, we succeeded in obtaining a low-cost X-ray cassette panel with a high degree of freedom in design with respect to joining with other parts while maintaining lightweight and uniform X-ray transparency.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing an example of an X-ray cassette panel according to the present invention. FIG. 2 is a cross-sectional view of the X-ray cassette panel shown in FIG.

  As shown in FIGS. 1 and 2, in the present invention, the X-ray cassette panel 1 has a sandwich structure in which the skin 2 is CFRP and the core 3 is a resin foam. The panels have different thicknesses, and the ratio of the maximum thickness to the minimum thickness is in the range of 1.5 to 3.0.

  In the panel, by setting the ratio of the maximum thickness to the minimum thickness within the range of 1.5 to 3.0, a panel structure having a non-uniform thickness is obtained, and a portion requiring high surface rigidity in the surface is a meat. On the other hand, the part that needs to be joined to the frame parts as the casing such as the outer periphery or where it is necessary to avoid interference with other interpolated parts is made thin, and the panel is made into an X-ray cassette. There is an advantage that the degree of freedom of the design is expanded when mounting to. For the above reasons, in the panel, the ratio of the maximum thickness to the minimum thickness is more preferably in the range of 1.6 to 2.6.

In the present invention, the skin 2 has a ratio of maximum thickness to minimum thickness (maximum thickness / minimum thickness) in the range of 1.0 to 1.3, more preferably in the range of 1.0 to 1.2. In addition, the product (kg / m ² ) of the core thickness and the apparent core density at an arbitrary position of the panel is 0 of the product (kg / m ² ) of the core thickness and the apparent core density at another arbitrary position of the panel. It is necessary to be within the range of 0.8 to 1.2 times, more preferably within the range of 0.85 to 1.15 times. Here, the apparent core density can be measured according to JIS K 7222 (2005).

  The skin 2 is necessary for ensuring high bending rigidity in the panel, and is composed of FRP containing carbon fiber. FRP is formed by impregnating a reinforcing fiber with a matrix resin. Since carbon fiber is contained in FRP, a panel having high specific strength and high specific modulus and high X-ray permeability can be obtained. As the carbon fiber, for example, polyacrylonitrile (PAN) -based, pitch-based, cellulose-based, hydrocarbon-grown vapor phase growth system, and the like can be used, and two or more of these may be used in combination. Among these, PAN-based carbon fibers having an excellent balance between elastic modulus and price are suitable for the present invention. In addition to carbon fiber, reinforcing fiber other than carbon fiber may be used for FRP. Examples of the reinforcing fiber include glass fiber, organic high modulus fiber (for example, polyaramid fiber “Kevlar manufactured by DuPont, USA). (Registered trademark) ”), high-strength, high-modulus fiber such as alumina fiber, silicon carbide fiber, boron fiber, silicon carbide fiber can be used, polyamide fiber, polyester fiber, acrylic fiber, polyolefin fiber, vinylon fiber Synthetic fibers such as organic natural fibers can also be used. A plurality of these reinforcing fibers can also be used in combination.

  As the matrix resin, a thermosetting resin or a thermoplastic resin can be used. Specifically, examples of the thermosetting resin include an epoxy resin, a phenol resin, an unsaturated polyester resin, a vinyl ester resin, and a cyanate resin. Examples of the thermoplastic resin include an ABS resin, a polyethylene terephthalate resin, and a polyamide. Examples thereof include a resin, a benzoxazine resin, a maleimide resin, and a polyimide resin. The matrix resin is preferably a resin that is cured by heat or external energy such as light or electron beam, such as a thermosetting resin, and at least partially forms a three-dimensional cured product, and uses an epoxy resin. Is particularly preferred.

  Here, the ratio of the maximum thickness to the minimum thickness (maximum thickness / minimum thickness) of the skin 2 is in the range of 1.0 to 1.3, more preferably in the range of 1.0 to 1.2. Thus, although the panel has a non-uniform thickness, the X-ray transmittance that transmits through the skin 2 tends to be the same at any position in the plane. In order to make the in-plane distribution of the X-ray transmittance transmitted through the skin 2 more uniform, in the fiber reinforced plastic used as the skin 2, the carbon fibers are uniformly arranged in the plane of the panel. It is preferable that it is easy to achieve stable strength and rigidity in the plane. It should be noted that the uniform arrangement in the plane of the panel means that the carbon fibers aligned in one direction in the plane are arranged without gaps, and the woven form or nonwoven fabric so that there is no large gap. It refers to being a form, and these plural forms may be continuously arranged in a plane, or the plural forms may be overlapped in the thickness direction.

The core 3 is for connecting the skins 2 positioned on the front and back of the FRP sandwich panel and maintaining the shape as a panel. The core is made of a resin foam, and the product (kg / m ² ) of the core thickness and the apparent core density at an arbitrary portion of the panel is the product (kg / m ² ) of the core thickness and the apparent core density at other arbitrary portions of the panel. ² ) must be in the range of 0.8 to 1.2 times, more preferably in the range of 0.85 to 1.15 times. As described above, the absolute value of the amount of X-ray transmission is almost inversely proportional to the product of the thickness and density of the transmitting material when passing through a structure made of the same material, so the product of the core thickness and the apparent core density. Is within the above range, the in-plane distribution of the X-ray transmittance transmitted through the core 3 can be made substantially uniform even if the thickness of the core 3 varies greatly within the panel surface.

  Moreover, it is preferable that the core 3 is the resin foam integrated without a joint. In this case, the transmittance of X-rays transmitted through the panel, which is assumed when the gap between the joints is large, changes locally at the joint part, and the strength and rigidity of the panel greatly change at the joint part. The generation of non-uniform distribution of X-ray transmittance due to scattering of the X-rays transmitted through the panel at the joint portion, which is assumed when there is a gap between the joints but is extremely small. Can be prevented.

  The resin foam is a foamed cell formed by mixing a foaming agent, hollow beads, and carbon dioxide with a thermosetting resin or thermoplastic resin. Examples of the thermosetting resin used for the resin foam include polyurethane, epoxy, phenol, and melamine. On the other hand, as the thermoplastic resin used for the resin foam, polyester resin such as polyamide resin, modified phenylene ether resin, polyacetal resin, polyphenylene sulfide resin, liquid crystal polyester, polyethylene terephthalate, polybutylene terephthalate, polycyclohexanedimethyl terephthalate, polyarylate Resin, polycarbonate resin, polystyrene resin, HIPS resin, ABS resin, AES resin, AAS resin and other styrene resins, polymethyl methacrylate resin and other acrylic resins, vinyl chloride, polyethylene and polypropylene polyolefin resins, modified polyolefin resins, heat Imide resins such as plastic polyimide, polymethacrylamide and polyetherimide, and ethylene / propylene copolymer , Ethylene / 1-butene copolymer, ethylene / propylene / diene copolymer, ethylene / carbon monoxide / diene copolymer, ethylene / glycidyl (meth) acrylate, ethylene / vinyl acetate / glycidyl (meth) acrylate There are various elastomers such as copolymers, polyether ester elastomers, polyether ether elastomers, polyether ester amide elastomers, polyester amide elastomers, polyester ester elastomers, and these may be used alone or in combination of two or more. It may be used as a mixture. Among them, it is preferable to use a thermoplastic resin such as polypropylene or polymethacrylimide, in which the foamed cells are closed cells and can easily form a uniform foamed cell shape.

  Further, when a foam of a thermoplastic resin is used as the core 3, the resin foam is interposed between the skin 2 and the core 3 in order to ensure sufficient bonding strength between the skin 2 and the core 3. As a thermoplastic resin that can be used as a body, a thin layer of a thermoplastic resin similar to that exemplified above (hereinafter referred to as a thermoplastic resin layer) is disposed, and the skin 2 and the core 3 are integrated by the thermoplastic resin layer. More preferably. As the thermoplastic resin layer, a thermoplastic resin film or a thermoplastic resin sheet can be used. In this case, a commercially available hot melt adhesive sheet can be used. The thermoplastic resin layer can also be formed by coating a thermoplastic resin. Furthermore, the thermoplastic resin layer may be a synthetic fiber woven fabric or nonwoven fabric made of a thermoplastic resin. Here, the thin layer of the thermoplastic resin is preferably a layer having a uniform thickness of 0.005 to 0.25 mm. By providing a thickness within this range, it is possible to suppress a decrease in rigidity as a panel and a non-uniform in-plane distribution of X-ray transmittance while securing a sufficient bonding force between the skin 2 and the core 3. Become.

Further, in order to increase the X-ray transmittance that passes through the core 3 and make the in-plane distribution of the X-ray transmittance more uniform, the core used has an apparent core density in the range of 200 to 900 kg / m ^3. More preferably, it is more preferably in the range of 250 to 600 kg / m ³ . When the apparent core density is within this range, the panel is reduced in weight, and the X-ray transmittance of the core 3 is greatly increased as compared with the skin 2, which leads to an improvement in the X-ray transmittance of the panel. Furthermore, when the apparent core density is within the above range, it is possible to ensure sufficient strength and rigidity as a panel structure even when used as an X-ray cassette. In order to make the in-plane distribution of the X-ray transmittance transmitted through the core 3 more uniform, the average diameter of the foam cells in the resin foam is within a range of 0.01 to 0.5 mm. More preferably, it is more preferably within a range of 0.01 to 0.3 mm. This is because if the average diameter of the foamed cells is within the above range, the local apparent core density distribution of the core 3 tends to be uniform, and X-ray scattering is difficult to occur inside the core 3. In addition, even when the thickness of the core 3 is thin (for example, when the thickness is 2 mm or less), variations in strength and rigidity hardly occur, and the FRP sandwich panel can easily obtain stable strength and rigidity.

  Moreover, by designing as described above, the X-ray cassette panel of the present invention has an X-ray transmission dose at an aluminum equivalent of 0.1 to 0. Within the range of 3 mm Al, the ratio of the maximum aluminum equivalent to the minimum aluminum equivalent in the panel can be in the range of 1.0 to 1.3. By being within such a range, the X-ray cassette panel of the present invention has improved X-ray transmittance as compared with the conventional flat CFRP single panel, and compared with the conventional flat FRP sandwich panel. Thus, it is possible to ensure the same X-ray transmittance distribution uniformity while providing a non-uniform thickness distribution within the panel. In medical radiology equipment, the ease of transmission of X-rays (total filtration amount) of a structure is evaluated by a parameter called aluminum equivalent (mmAl). This is a measure of how much the X-ray transmittance of the structure corresponds to the thickness of aluminum, and the smaller the aluminum equivalent, the higher the X-ray transmittance, and the more preferable the panel for the X-ray cassette.

  The thickness of the X-ray cassette panel is preferably as thin as possible due to the improvement in X-ray transparency and the restrictions on the shape when mounting the cassette (as defined in JIS Z 4905 (2005)). However, since the X-ray cassette panel needs to have practically sufficient strength and rigidity, the maximum thickness of the panel is actually in the range of 0.5 to 5 mm, more preferably 1.0 to 3 It is preferable to be within a range of .5 mm. By setting the maximum thickness of the panel within this range, it is possible to obtain an X-ray cassette panel in which X-ray permeability, strength, and rigidity are designed in a well-balanced manner.

  In addition, the X-ray cassette panel of the present invention preferably includes a portion where at least a part of the outer peripheral portion is thinner than the average thickness of the entire panel. FIG. 3 is a perspective view showing a fitting state between the X-ray cassette panel 1 and the frame member 4. As shown in FIG. 3, the outer peripheral portion of the X-ray cassette panel 1 is often joined to a frame member 4 constituting a part of the housing, and a thin wall portion is provided on the outer peripheral portion of the panel so Easy to avoid interference between parts. In addition, when joining the frame material 4 at the outer peripheral portion of the panel, a through-hole 5 for fitting is often installed in a part of the panel, but the minimum thickness of the panel, like the thin-walled portion of the outer periphery. If the through-hole 5 for fitting is installed at a position having a thickness within the range of 1.0 to 1.5 times the thickness, the thin-walled portion has high apparent core density and high compression rigidity, so drilling is performed. This makes it possible to ensure sufficient compression rigidity in the thickness direction required for fitting.

  The X-ray cassette panel of the present invention is used for an X-ray cassette which is a general X-ray imaging equipment part, and in particular, an X-ray which is a part of a medical X-ray diagnostic equipment requiring X-ray transparency. It is most preferable to be used in a cassette from the viewpoints of improving X-ray permeability, uniformity and strength of transmittance distribution, and improving rigidity.

  The X-ray cassette panel of the present invention can be manufactured at a low cost by adopting the following method. FIG. 4 is a process schematic diagram for explaining the production method of the present invention. As shown to Fig.4 (a), the resin foam sheet 6 and the prepreg 7 containing carbon fiber are prepared. The resin foam sheet 6 usually has a substantially uniform thickness and a substantially uniform bulk density. Here, the uniform thickness and the uniform bulk density mean a uniformity within a variation of ± 10% with respect to the respective average values, and the bulk density of the resin foam sheet is JIS K 7222 ( 2005). Further, the prepreg 7 may include a reinforcing fiber other than the carbon fiber as described above in addition to the carbon fiber, and the reinforcing fiber such as the carbon fiber is impregnated with the matrix resin as described above. ing.

  And as shown in FIG.4 (b), the prepreg 7 is arrange | positioned on both front and back both surfaces of the resin foam sheet 6, and the preform 8 is formed. Here, the prepreg arranged on one side may be a single prepreg, or a plurality of prepregs may be continuously arranged or overlapped. The matrix resin used for the prepreg is preferably a thermosetting resin.

  Next, as shown in FIG. 4C, the upper mold 9 and the lower mold 10 in which the concave and convex cavities are formed are opened, and the preform 8 is disposed between them.

  Here, the upper mold and the lower mold are preferably molds, and the upper mold and the lower mold are preferably installed in a mold clamping mechanism of a hot press apparatus.

  Then, as shown in FIG. 4D, after the preform 8 is arranged, the upper mold and the lower mold are clamped and molded. By clamping the mold, an uneven cavity is formed by the upper mold and the lower mold, and the panel 1 is formed along the shape of the cavity. In molding, heating and pressurization are generally performed. Here, for example, by controlling the shape of the cavity and the thickness of the preform, the minimum thickness of the molded panel is 0.2 to 0.6 times the thickness of the preform 8, preferably 0.3 to 0. .55 times, more preferably within a range of 0.35 to 0.55 times, and the maximum thickness is 0.3 to 0.9 times, preferably 0.5 to 0.9 times the thickness of the preform 8. More preferably, it is within the range of 0.7 to 0.9 times, and the ratio of the maximum thickness and the minimum thickness of the panel is within the range of 1.5 to 3.0. By this molding, an X-ray cassette panel in which the skin and the core are integrated can be manufactured. Here, the resin foam used as the core should have a compressive strength (10%) at 130 ° C. of 0.5 to 20 MPa, preferably 2 to 20 MPa so that it can withstand heat and pressure in molding. good. Here, the compressive strength (10%) at 130 ° C. of the resin foam can be measured according to JIS K 7220 (2006). Similarly, when a resin foam using a thermoplastic resin is used as the core so that it can withstand heat and pressure in molding, the thermoplastic resin used has a melting point within the range of 140 to 350 ° C. It is good to use what is.

  According to the manufacturing method of the present invention, it is not necessary to pre-mold the core into a desired concavo-convex shape in advance, or it is possible to perform simultaneous molding without the need to adhesively bond the skin and the core molded separately. Panel for X-ray cassette can be provided at low cost.

Hereinafter, the present invention will be described more specifically with reference to examples. In this example, the tensile elastic modulus of the reinforcing fiber, the carbon fiber content and the glass fiber content in the fiber reinforced plastic, the deflection amount at the load point of the panel, the aluminum equivalent of the panel, the thickness of the skin, the core thickness in the panel And the apparent core density were measured as follows.
(A) Tensile elastic modulus of reinforcing fiber The tensile elastic modulus of the reinforcing fiber was measured according to the resin impregnated fiber bundle test method of the carbon fiber test method of JIS R 7601 (1986). The test piece length was 200 mm, the number of tests was 5, and the average value was adopted.
(B) Carbon Fiber Content of Fiber Reinforced Plastic The carbon fiber weight content of the fiber reinforced plastic was measured in accordance with the test method for prepreg composed of carbon fiber and epoxy resin according to JIS K7071 (1988). The dimension of the test piece was 100 mm × 100 mm, the number of tests was 3 times, and the average value was adopted.
(C) Glass fiber content of fiber reinforced plastic JIS K 7052 (1999) glass long fiber reinforced plastic-prepreg, molding material and molded article-Determination of glass long fiber and inorganic filler content-Method of firing method According to A, the glass fiber weight content of the fiber reinforced plastic was measured. The number of tests was three, and the average value was adopted.
(D) Deflection amount at panel load point When comparing the two sides of the panel, the surface with the larger surface area faces upward, and as shown in FIG. In the state where the aluminum frame and the three outer edges were fixed and placed flat, a load of 50 N was applied to the center of the panel with a round indenter with a radius of 10 mm, and the deflection at the load point was measured.
(E) Aluminum Equivalent of Panel X-ray at an X-ray irradiation tube voltage of 60 kV using an X-ray irradiation device with respect to a panel to be measured with respect to a total of 10 places including a maximum thickness portion and a minimum thickness portion and set arbitrarily. When the both surfaces of the panel were compared with each other, the panel was irradiated from the surface with the larger surface area perpendicularly to the panel, and the X-ray dose transmitted through the panel was measured with a dosimeter. Then, the aluminum equivalent was calculated from the obtained transmitted X-ray dose. In this example, a diagnostic X-ray high voltage apparatus KXO-30F manufactured by Toshiba Corporation was used as the X-ray irradiation apparatus, and a model No. manufactured by Radical Corporation was used as the dosimeter. A 2025 Radiation Monitor was used.
(F) Thickness of skin For the sandwich panel, the cross section of a total of 10 places including the maximum thickness part and the minimum thickness part and other arbitrarily set are magnified 100 times with a digital microscope, and the skin thickness is displayed on the digital image. It was measured. In this example, VHX-500 manufactured by Keyence Corporation was used as a digital microscope.
(G) The product of core thickness and apparent core density in the panel About the sandwich panel, the cross section of a total of 10 locations including the maximum thickness portion and the minimum thickness portion and other arbitrarily set was magnified 100 times with a digital microscope, The core thickness was measured on the digital image. In this example, VHX-500 manufactured by Keyence Corporation was used as a digital microscope. Subsequently, a part of the core was sampled from the same part as these 10 parts, and the apparent core density was measured based on JIS K 7222 (2005). And the product (kg / m < ² >) of the core thickness and the apparent core density was calculated | required from the obtained core thickness and the apparent core density.
<Example 1>
Continuous carbon fiber with a tensile modulus of 230 GPa ("Torayca (registered trademark)" T700S-12K manufactured by Toray Industries, Inc.) is aligned in one direction in a sheet shape, and the carbon fiber basis weight impregnated with an epoxy resin is 100 g / m ² , carbon A unidirectional prepreg having a fiber content of 63% by weight was prepared. Four pieces of this prepreg were cut out in a size of 400 mm in length × 400 mm in width, and two pieces were bonded at room temperature so that the orientation angle was (0 ° / 90 °) to obtain two prepreg laminates. Here, the orientation angle of 0 ° is defined as a length parallel to 400 mm. Further, a polypropylene resin foam sheet ("Fcel (registered trademark)" CP3030 manufactured by Furukawa Electric Co., Ltd.) having a uniform bulk density of 3 mm and a bulk density of 330 kg / m ³ is 400 mm long by 400 mm wide. Prepared in size.

  These are laminated at room temperature with the outer circumference aligned so that the order of the prepreg laminate with an orientation angle of (0 ° / 90 °), the polypropylene resin foam sheet, and the prepreg laminate with an orientation angle of (90 ° / 0 °). Together, a preform with a thickness of 3.4 mm was obtained.

  Subsequently, when the mold is clamped, the upper mold and the lower mold having cavities that conform to the concave and convex shape of FIG. Place the resulting preform on top. Furthermore, the upper mold after the mold release treatment is fixed to the upper ram of the hot press apparatus, and the mold is clamped between the upper mold and the lower mold so that the temperature is 130 ° C. and the pressure to the preform is 2 MPa. While being heated and pressed for 60 minutes, the prepreg laminate was cured, and the prepreg and the resin foam were adhesively bonded. Thereafter, the upper mold and the lower mold are opened, the molded product is taken out and slowly cooled, and then the outer periphery trimming and 6 fitting holes in the vicinity of the outer periphery are machined by an NC router, and the length is 370 mm × width as shown in FIG. A panel for X-ray cassette of 370 mm was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 2>
A continuous carbon fiber having a tensile elastic modulus of 230 GPa ("Torayca (registered trademark)" T300B-3K manufactured by Toray Industries, Inc.) is used for a plain woven fabric having a strand density of 12.5 / 25 mm for both warp and weft. A cross prepreg having a carbon fiber basis weight of 200 g / m ² impregnated with an epoxy resin and a carbon fiber content of 56% by weight was prepared. Two pieces of this prepreg were cut out in a size of 400 mm long × 400 mm wide. Here, the orientation angle of the cross prepreg was set so that the warp yarn was parallel to the length of 400 mm. Further, a polypropylene resin foam sheet ("Fcel (registered trademark)" CP3030 manufactured by Furukawa Electric Co., Ltd.) having a uniform bulk density of 3 mm and a bulk density of 330 kg / m ³ is 400 mm long by 400 mm wide. Prepared in size.

These were aligned at room temperature with the outer circumference aligned in the order of cross prepreg, polypropylene resin foam sheet, and cross prepreg to obtain a preform having a thickness of 3.4 mm. Thereafter, for the X-ray cassette of 370 mm length × 370 mm width as shown in FIG. 5 except that the preform used in Example 1 was changed to the preform obtained as described above. I got a panel.
Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 3>
The polypropylene resin foam sheet was changed to a polypropylene resin foam sheet having a uniform thickness of 3 mm and a bulk density of 290 kg / m ³ (“F-cell (registered trademark)” CP4030, manufactured by Furukawa Electric Co., Ltd.). A preform having a thickness of 3.4 mm was obtained in the same manner as in Example 1 except that it was used. Furthermore, using the upper mold and the lower mold having cavities such as those shown in FIG. 6 except that the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 6 was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 4>
The polypropylene resin foam sheet was changed to a polypropylene resin foam sheet having a uniform thickness of 3 mm and a bulk density of 290 kg / m ³ (“F-cell (registered trademark)” CP4030, manufactured by Furukawa Electric Co., Ltd.). A preform having a thickness of 3.4 mm was obtained in the same manner as in Example 2 except that it was used. Furthermore, using the upper mold and the lower mold having cavities such as those shown in FIG. 6 except that the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 6 was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 5>
The polypropylene resin foam sheet was changed to a polypropylene resin foam sheet having a uniform thickness of 3 mm and a bulk density of 290 kg / m ³ (“F-cell (registered trademark)” CP4030, manufactured by Furukawa Electric Co., Ltd.). A preform having a thickness of 3.4 mm was obtained in the same manner as in Example 1 except that it was used. Furthermore, using the upper mold and the lower mold having cavities that conform to the concavo-convex shape of FIG. 7, the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 7 was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 6>
The polypropylene resin foam sheet was changed to a polypropylene resin foam sheet having a uniform thickness of 3 mm and a bulk density of 290 kg / m ³ (“F-cell (registered trademark)” CP4030, manufactured by Furukawa Electric Co., Ltd.). A preform having a thickness of 3.4 mm was obtained in the same manner as in Example 2 except that it was used. Furthermore, using the upper mold and the lower mold having cavities that conform to the concavo-convex shape of FIG. 7, the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 7 was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of the weight, the amount of deflection, the absolute value of aluminum equivalent and the distribution, this panel is light and highly rigid, and has excellent uniform X-ray transmission, and is suitable as an X-ray cassette panel.
<Example 7>
In the same manner as in Example 1, two prepreg laminates and a polypropylene resin foam sheet having a uniform thickness of 3 mm and a bulk density of 330 kg / m ³ (manufactured by Furukawa Electric Co., Ltd. “Fcell”) ) "CP3030) One sheet was prepared in a size of 400 mm long by 400 mm wide. Furthermore, two nonwoven fabric sheets having a fiber basis weight of 16 g / m ² made of a low melting point polypropylene fiber having a melting point of 125 ° C. and a thickness of 0.015 mm were prepared in a size of 400 mm length × 400 mm width.

  These are arranged in the order of a prepreg laminate having an orientation angle of (0 ° / 90 °), a nonwoven fabric sheet, a polypropylene resin foam sheet, a nonwoven fabric sheet, and a prepreg laminate having an orientation angle of (90 ° / 0 °). Were bonded together at room temperature to obtain a preform having a thickness of 3.45 mm.

  Furthermore, using the upper mold and the lower mold having cavities that conform to the concavo-convex shape of FIG. 5, the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 5 was obtained.

Table 1 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection amount, absolute value of aluminum equivalent and distribution, this panel is lightweight and highly rigid, yet has excellent X-ray uniform permeability, and the bonding strength between skin and core. And is suitable as a panel for an X-ray cassette.
<Comparative example 1>
A flat plate having a length of 370 mm and a width of 370 mm as shown in FIG. 8 in the same manner as in Example 1 except that the upper die and the lower die are used by changing to those having a flat cavity without an uneven shape. A panel for X-ray cassette was obtained.
Table 2 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection, absolute value of aluminum equivalent and distribution, this X-ray cassette panel is lightweight and excellent in uniform X-ray transmission, but the rigidity needs to be improved for use in X-ray cassette. It is.
<Comparative example 2>
A thickness of 3.4 mm was obtained in the same manner as in Example 1 except that the polypropylene resin foam sheet was changed to a polypropylene resin foam sheet having a uniform bulk density of 160 kg / m ^{3 and} a uniform thickness of 3 mm. Got a preform. Furthermore, using the upper mold and the lower mold having cavities that conform to the concavo-convex shape of FIG. 9, the preform used in Example 1 was changed to the preform obtained as described above. In the same manner as in Example 1, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. 9 was obtained.

Table 2 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection amount, absolute value of aluminum equivalent and distribution, this panel is lightweight and excellent in uniform X-ray transmission, but the panel cannot sufficiently satisfy rigidity as an X-ray cassette panel. .
<Comparative Example 3>
Using the same prepreg and laminating method as in Example 1, two prepreg laminates were obtained. Furthermore, a polypropylene resin foam sheet ("F-cell" CP3030 manufactured by Furukawa Electric Co., Ltd.) having a uniform bulk density of 3 mm and a bulk density of 330 kg / m ³ is prepared in a size of 400 mm in length and 400 mm in width. Then, this sheet was machined by an NC router so that a portion corresponding to a thin portion of the outer peripheral portion had a thickness of 1.8 mm as shown in FIG.

  The outer periphery is aligned so that the prepreg laminate with the orientation angle (0 ° / 90 °), the polypropylene resin foam sheet after machining, and the prepreg laminate with the orientation angle (90 ° / 0 °) are in order. Then, a preform having a maximum thickness of 3.4 mm and a minimum thickness of 2.2 mm was obtained.

  Thereafter, for the X-ray cassette of 370 mm length × 370 mm width as shown in FIG. 5 except that the preform used in Example 1 was changed to the preform obtained as described above. I got a panel.

Table 2 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection amount, absolute value of aluminum equivalent and distribution, this panel is lightweight and excellent in rigidity, but as a panel for X-ray cassette, it cannot sufficiently satisfy the uniform transmission of X-rays. .
<Comparative example 4>
Using the same prepreg as in Example 1, a single prepreg laminate having a size of 400 mm in length and 400 mm in width was obtained in the same manner as in Example 1. The other prepreg laminate is such that the thinnest part of the outer periphery of the prepreg laminate is 400 mm long × 400 mm wide, and the orientation angle is (0 ° / 90 °), for a total of two layers. The orientation angle of the thickest part is (0 ° / 90 ° / 0 ° /... / 0 ° / 90 ° / 0 °) for a total of 14 layers, and the middle part between the thinnest part and the thickest part Is a lamination method in which the thickness of the prepreg laminate is smoothly changed by continuously changing the number of laminations. Furthermore, one polypropylene resin foam sheet ("F-cell" CP3030 manufactured by Furukawa Electric Co., Ltd.) having a uniform bulk density of ³ kg and a bulk density of 330 kg / m3 is prepared in a size of 400 mm in length and 400 mm in width. did.

  These are laminated at room temperature with the outer circumference aligned so that the order of a prepreg laminate, polypropylene resin foam sheet having a different number of layers, and a prepreg laminate having a constant number of layers, a maximum thickness of 4.6 mm and a minimum thickness of 3 A 4 mm preform was obtained.

Thereafter, the preform used in Example 1 was changed to the preform obtained as described above, and the preform was placed on the lower mold with the prepreg laminate side having a fixed number of layers facing down. Obtained an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG.
Table 2 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection amount, absolute value of aluminum equivalent and distribution, this panel is lightweight and excellent in rigidity, but as a panel for X-ray cassette, it cannot sufficiently satisfy the uniform transmission of X-rays. .
<Comparative Example 5>
Tensile aligned in sheet form continuous glass fiber modulus of elasticity 73 GPa (Nitto Boseki Co., Ltd. ECG37) in one direction, the glass fibers impregnated with an epoxy resin basis weight 100 g / ^{m 2,} the glass fiber content 63 wt% of the UD A prepreg was prepared. Four pieces of this prepreg were cut into a size of 400 mm in length and 400 mm in width, and two pieces were bonded at room temperature so that the orientation angle was (0 ° / 90 °) to obtain two prepreg laminates. Here, the orientation angle of 0 ° is defined as a length parallel to 400 mm. Furthermore, one polypropylene resin foam sheet ("F-cell" CP3030 manufactured by Furukawa Electric Co., Ltd.) having a uniform bulk density of ³ kg and a bulk density of 330 kg / m3 is prepared in a size of 400 mm in length and 400 mm in width. did.

  These are laminated at room temperature with the outer circumference aligned so that the order of the prepreg laminate with an orientation angle of (0 ° / 90 °), the polypropylene resin foam sheet, and the prepreg laminate with an orientation angle of (90 ° / 0 °). Together, a preform with a thickness of 3.4 mm was obtained.

  Except that the preform used in Example 1 was changed to the preform obtained as described above, an X-ray cassette panel having a length of 370 mm and a width of 370 mm as shown in FIG. Obtained.

    Table 2 shows the results of measuring the structure and performance of the obtained panel. From the measurement results of weight, deflection amount, absolute value of aluminum equivalent and distribution, this panel is lightweight and excellent in uniform X-ray transmission, but the panel cannot sufficiently satisfy rigidity as an X-ray cassette panel. .

  The present invention is not limited to the X-ray cassette used for medical X-ray diagnosis, and can be applied to any X-ray cassette that requires light weight and high rigidity.

It is a perspective view of the panel for X-ray cassettes concerning one embodiment of the present invention. It is sectional drawing in the AA surface of the panel for X-ray cassettes shown in FIG. It is a perspective view which shows the fitting state of the panel for X-ray cassettes and frame material which concern on one embodiment of this invention. It is process schematic explaining the manufacturing method of the panel for X-ray cassettes concerning one embodiment of this invention. It is a perspective view of the panel for X-ray cassettes obtained in Examples 1, 2, and 7 and Comparative Examples 3, 4, and 5. It is a perspective view of the panel for X-ray cassettes obtained in Examples 3 and 4. It is a perspective view of the panel for X-ray cassettes obtained in Examples 5 and 6. 6 is a perspective view of an X-ray cassette panel obtained in Comparative Example 1. FIG. 6 is a perspective view of an X-ray cassette panel obtained in Comparative Example 2. FIG.

Explanation of symbols

1: Panel for X-ray cassette 2: Skin 3: Core 4: Frame material 5: Through hole 6: Resin foam sheet 7: Prepreg 8: Preform 9: Upper mold 10: Lower mold

Claims (10)

A panel for X-ray cassette having a sandwich structure in which a skin is a fiber reinforced plastic including carbon fibers and a core is a resin foam, and the ratio of the maximum thickness to the minimum thickness is 1.5 to 3.0. And the skin has a ratio of the maximum thickness to the minimum thickness within the range of 1.0 to 1.3, and the product of the core thickness and the apparent core density at any part of the panel ( kg / ^{m 2)} is, X-rays, characterized in that in any other portion of the panel is in the range 0.8 to 1.2 times the core thickness and apparent core density of the product (kg / ^{m 2)} Panel for cassette. 2. The X-ray cassette panel according to claim 1, wherein in the fiber reinforced plastic, the carbon fibers are uniformly arranged in the plane of the panel. The panel for an X-ray cassette according to claim 1 or 2, wherein the core is a resin foam integrated without a joint. The panel for X-ray cassettes according to any one of claims 1 to 3, wherein the resin foam is made of a thermoplastic resin. The panel for X-ray cassettes according to any one of claims 1 to 4, wherein the skin and the core are integrated by a thermoplastic resin layer disposed between them. At an X-ray irradiation tube voltage of 60 kV, the X-ray transmission dose at an arbitrary point in the panel is in the range of 0.1 to 0.3 mm Al in terms of aluminum equivalent, and the ratio between the maximum aluminum equivalent and the minimum aluminum equivalent in the panel The panel for X-ray cassettes in any one of Claims 1-5 whose range is 1.0-1.3. The panel for X-ray cassettes according to any one of claims 1 to 6, wherein the panel has a maximum thickness in a range of 0.5 to 5 mm. The panel for X-ray cassettes according to any one of claims 1 to 7, wherein the panel is provided with a through hole at a position having a thickness within a range of 1.0 to 1.5 times the minimum thickness. . A prepreg containing carbon fibers is placed on both the front and back sides of the resin foam sheet to form a preform, and an upper mold and a lower mold where a concave and convex cavity is formed are opened, and the preform is placed between them. After that, the upper mold and the lower mold are clamped, and the molded panel has a minimum thickness of 0.2 to 0.6 times the thickness of the preform and a maximum thickness of 0. 0 to the thickness of the preform. A panel for an X-ray cassette, characterized in that it is molded within a range of 3 to 0.9 times and a ratio of the maximum thickness and the minimum thickness of the panel is within a range of 1.5 to 3.0. Manufacturing method. The method for producing an X-ray cassette panel according to claim 9, wherein the resin foam sheet has a substantially uniform thickness and a substantially uniform bulk density.

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