JPH0562720B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of the Invention] The present invention relates to a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor. More particularly, the present invention relates to a radiation image storage panel having a support and a phosphor layer provided thereon comprising a binder containing and supporting a stimulable phosphor. [Technical Background of the Invention and Prior Art] As a method of obtaining a radiographic image as an image, a so-called radiographic method has conventionally been used, which uses a combination of a radiographic film having an emulsion layer made of a silver salt photosensitive material and an intensifying screen. has been done. Recently, a radiation image conversion method using a stimulable phosphor, as described in Japanese Patent Application Laid-open No. 55-12145, has been attracting attention as an alternative to the above-mentioned radiographic method. Summer. This radiation image conversion method uses a radiation image conversion panel (stimulable phosphor sheet) containing a stimulable phosphor. Accumulated in the stimulable phosphor by absorbing it into the stimulable phosphor and then exciting the stimulable phosphor with electromagnetic waves (excitation light) such as visible light or infrared rays in a time-series manner. Radiation energy is emitted as fluorescence (stimulated luminescence), this fluorescence is read photoelectrically to obtain an electrical signal, and the obtained electrical signal is converted into an image. The above-mentioned radiation image conversion method has the advantage that a radiation image rich in information can be obtained with a much lower exposure dose than conventional radiography methods. Therefore, this radiation image conversion method has a very high utility value especially in direct medical radiography such as X-ray photography for the purpose of medical diagnosis. The radiation image conversion panel used in the above-mentioned radiation image conversion method has a basic structure including a support such as a plastic sheet, and a phosphor layer provided on one side of the support containing and supporting a stimulable phosphor in a dispersed state. It consists of The surface of this phosphor layer opposite to the support (the surface not facing the support) is usually used to protect the phosphor layer from chemical deterioration or physical impact, and to protect the phosphor layer from chemical deterioration or physical impact. A transparent protective film such as polyethylene terephthalate is provided to smooth the surface. In implementing the radiation image conversion method, the radiation image conversion panel performs radiation irradiation (radiation image recording) and
Irradiation of excitation light (reading of recorded radiation image)
It is used repeatedly in a cycle of irradiation with erasing light (erasing the remaining radiation image). The transfer of the radiation image conversion panel to each step is carried out by a conveyance system, and after one cycle is completed, the panels are sequentially stacked and stored. During this continuous cycle from transport to stacking, contact and friction between the radiation image conversion panels occur repeatedly, so the surface of the panel made of polymer material (the surface on the phosphor layer side) is easily charged. This causes various problems in implementing the radiation image conversion method. For example, as a result of the surface of a radiation image storage panel becoming electrically charged, when the panels are transferred from a stacked state to a conveyance system, the front surface of the panel and the back surface of another panel (surface on the support side) may come into close contact with each other, resulting in two overlapping panels. This makes it easy for them to be sent into the conveyance system in such a state that it becomes impossible to perform normal operations thereafter. In addition, dust in the air tends to adhere to the panel surface. In such a panel, the excitation light is scattered by dust adhering to the surface during readout, resulting in an image whose quality is significantly degraded. Incidentally, the phosphor layer is generally prepared by adding particles of stimulable phosphor and a binder to a suitable solvent to prepare a coating solution in which the phosphor is uniformly dispersed in the binder solution, and then applying this coating solution using a doctor blade or the like. The phosphor layer is attached to the support by directly coating the support using a roll coater or the like and then drying it, or by bonding a phosphor layer formed by coating on a separate sheet to the support. Therefore, the stimulable phosphor particles are almost uniformly dispersed and present in the phosphor layer. Furthermore, the surface of this phosphor layer is generally coated with a solution made of a transparent polymer substance.
Alternatively, a protective film is provided by adhering a separately formed transparent thin film using an adhesive or the like. The present applicant has developed a method for applying stimulable phosphor on a support by simultaneous multilayer coating using a binder solution in which a stimulable phosphor is dispersed and a binder solution that does not contain a stimulable phosphor. We have already filed a patent application for a radiation image conversion panel and a method for providing a phosphor layer consisting of a portion where stimulable phosphor is present and a portion where stimulable phosphor is not substantially present (Japanese Patent Application No. 182212-1982).
issue). Therefore, in the panel manufactured by this method, no coating film interface is formed, and the phosphor layer also functions as a protective film. [Object of the Invention] An object of the present invention is to provide a radiation image conversion panel with excellent antistatic effect and a method for manufacturing the same. Another object of the present invention is to provide a radiation image storage panel with particularly improved transport characteristics and a method for manufacturing the same. The above object is to provide a radiation image conversion panel having a support and a phosphor layer provided on the phosphor layer made of a supporting binder containing a stimulable phosphor, in which the phosphor layer is stimulable on the support side. It consists of a part where the stimulable phosphor is present and a part where the stimulable phosphor is not present on the panel surface side, and there is no interface between the two parts, and the stimulable phosphor is substantially present. This can be achieved by the radiation image storage panel of the present invention, which is characterized in that an antistatic agent made of an inorganic metal salt is contained in the non-containing portions. Note that the above-mentioned statement that "stimulable phosphor is not present on the front surface side of the panel" does not exclude a state in which a small amount of stimulable phosphor particles are mixed in. In addition, the above purpose is to (1) make a binder solution () containing a stimulable phosphor dispersed therein and a binder solution () containing an antistatic agent made of an inorganic metal salt so that they are compatible with each other; A binder solution prepared using a solvent having the following properties and then dispersing the stimulable phosphor ()
A method for producing a radiation image conversion panel according to the present invention, characterized in that the panel is simultaneously coated in multiple layers on the surface of a support so that the stimulable phosphor is on the support side, and (2) a binder solution containing a stimulable phosphor dispersed therein. and a binder solution containing an antistatic agent consisting of an inorganic metal salt were prepared using mutually compatible solvents, and then coated simultaneously on a flat sheet in multiple layers to form a phosphor layer. This can be advantageously achieved by a method for producing a radiation image storage panel, which is characterized in that the phosphor layer is then separated from the sheet and attached onto a support. In the present invention, the panel surface side means the side of the phosphor layer that is opposite to the side that is in contact with the support. [Effects of the Invention] The present invention provides a method in which the stimulable phosphor particles are present in a dispersed state only in a certain region on the support side in the phosphor layer of a radiation image conversion panel comprising a stimulable phosphor and a binder. On the other hand, by containing only an antistatic agent without substantially phosphor particles present in a certain area on the panel surface side, charging phenomenon in the conveyance system is prevented and smooth recording and reproduction of radiation images is realized. It is something to do. In the past, a phosphor layer was generally formed by applying a binder solution (coating liquid) in which phosphor particles were uniformly dispersed onto a support using a normal coating method. The particles were contained and supported in a dispersed state throughout the phosphor layer by the binder. In the present invention, a coating solution () containing dispersed phosphor particles and a binder solution () containing only an antistatic agent without containing phosphor particles are applied to the support side. By arranging and simultaneously coating the support in a layered manner, a binder part where the antistatic agent exists in a dispersed state and a part where the phosphor particles exist in a dispersed state are formed in the depth direction of the phosphor layer. can do. That is, the phosphor particles exist in a dispersed state in a certain area on the support side of the phosphor layer, the antistatic agent exists in a dispersed state in a certain area on the opposite side of the panel surface, and the phosphor particles are substantially present in a certain area on the panel surface side. A phosphor layer that does not exist is formed. Therefore, since the portion containing the antistatic agent is formed on the surface side of the obtained radiation image storage panel, charging phenomenon can be effectively prevented. In addition, the part containing this antistatic agent has a flat surface and can play the same role as a protective film to protect the phosphor from chemical changes and physical impact. Thus, there is no need to provide a protective film on the phosphor layer as a separate process, and the manufacturing process of the radiation image conversion panel can be simplified. In addition, as in conventional radiation image conversion panels, when a protective film is attached between the phosphor layer and the protective film, or when it is attached via an adhesive layer, the phosphor layer This means that no interface is formed between the adhesive layer and the protective film. Therefore, the mechanical strength (adhesion strength, etc.) of the panel can be improved. Furthermore, scattering of excitation light does not occur at these interfaces, making it possible to obtain images with improved image quality such as sharpness and graininess. At the same time, since no fluorescence scattering occurs at the interface, it is possible to improve image quality and increase sensitivity. [Structure of the Invention] The radiation image conversion panel of the present invention having the preferable characteristics as described above can be manufactured, for example, by the following manufacturing method. The phosphor layer, which is a characteristic feature of the present invention, is a layer consisting essentially of a portion containing photostimulable phosphor particles on the support side and a portion containing an antistatic agent on the panel surface side. , are both supported by a binder. As mentioned above, a stimulable phosphor is a phosphor that exhibits stimulated luminescence when irradiated with radiation and then with excitation light, but from a practical standpoint, the waveform is
300-500nm with excitation light in the 900nm range
It is desirable that the phosphor exhibits stimulated luminescence in the wavelength range of . Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention include those described in U.S. Pat. No. 3,859,527.
SrS: Ce, Sm, SrS: Eu, Sm, ThO ₂ : Er, and La ₂ O ₂ S: Eu, Sm, described in JP-A-55-12142.
ZnS: Cu, Pb, BaO・xAl ₂ O ₃ : Eu (however, 0.8
<x≦10), and M〓O・xSiO ₂ :A (however,
M〓 is Mg, Ca, Sr, Zn, Cd, or Ba,
A is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or
Mn and x is _0.5 ≦x≦2.5), (Ba ¹ _-Xy , _Mg
is at least one of Cl and Br,
x and y are 0<x+y≦0.6 and xy≠0, and a is ^10-6 ≦a≦5× ^10-2 ), as described in JP-A-55-12144.
LnOX:xA (Ln is La, Y, Gd, and
At least one of Lu, X is at least one of Cl and Br, A is at least one of Ce and Tb, and x is 0<x<0.1
(Ba _1-x , M ²⁺ _x ) FX:yA (where M ²⁺ is Mg,
At least one of Ca, Sr, Zn, and Cd, X is at least one of Cl, Br, and I, A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
at least one of Nd, Yb, and Er; x is 0≦x≦0.6; y is 0≦y≦0.2);
FX・xA: yLn [However, M〓 is Ba, Ca, Sr,
At least one of Mg, Zn, and Cd, A
are BeO, MgO, CaO, SrO, BaO, ZnO,
Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ ,
ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and
At least one of ThO ₂ , Ln is Eu, Tb,
Ce, Tm, Dy, Pr, Ho, Nd, Yb, Er, Sm,
and at least one of Gd, X is Cl,
At least one of Br, and I,
x and y are respectively 5×10 ^-5 ≦x≦0.5 and 0<y≦0.2] A phosphor is described in JP-A-56-116777 (Ba _{1- x} , M〓x(F ₂・aBaX ₂ :yEu, zA [however,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium; X is at least one of chlorine, bromine, and iodine; A is at least one of zirconium and scandium;
a, x, y, and z are each 0.5≦a≦1.25,
0≦x≦1, 10 ^-6 ≦y≦2×10 ^-1 , and 0<z
≦10 ^-2 ], described in Japanese Patent Application Laid-Open No. 57-23673, (Ba _1-x , M〓x)F ₂・aBaX ₂ :yEu, zB [However, ,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium;
10 ^-6 ≦y≦2×10 ^-1 and 0<z≦2×10 ^-1 ] A phosphor is described in JP-A-57-23675 (Ba _{1 -x} , M〓x)F ₂・aBaX ₂ :yEu, zA [However,
M〓 is beryllium, magnesium, calcium,
at least one of strontium, zinc, and cadmium; X is at least one of chlorine, bromine, and iodine; A is at least one of arsenic and silicon; a, x, y, and z are each 0.5 ≦a≦1.25, 0≦x≦1, 10 ^-6
≦y≦2×10 ⁻¹ and 0<y≦5×10 ¹ ]
A phosphor represented by the composition formula M
OX: xCe [However, M〓 is Pr, Nd, Pm, Sm,
At least one trivalent metal selected from the group consisting of Eu, Tb, Dy, Ho, Er, Tm, Yb, and Bi, X is one or both of Cl and Br, and x is 0<x<0.1] A phosphor is described in JP-A-58-206678.
Ba _1-x M _x/2 L _x/2 FX:yEu ²⁺ [However, M is Li, Na,
Represents at least one alkali metal selected from the group consisting of K, Rb, and Cs; L is Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb,
represents at least one trivalent metal selected from the group consisting of Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, In, and Tl; X represents Cl, Br, and I;
and x is 10 ^-2 ≦x≦0.5, and y is 0<y≦0.1] JP-A-59-27980 stated in the issue
BaFX・xA:yEu ²⁺ [wherein, 10 ^-6 ≦x≦
0.1, y is 0<y≦0.1], which is described in Japanese Patent Application Laid-open No. 59-47289.
BaFX・xA:yEu ²⁺ [However, X is at least one halogen selected from the group consisting of Cl, Br, and I; A is hexafluorosilicic acid,
x is a fired product of at least one compound selected from the hexafluoro compound group consisting of monovalent or divalent metal salts of hexafluorotitanic acid and hexafluorozirconic acid;
10 ^-6 ≦x≦0.1, y is 0<y≦0.1] A phosphor described in JP-A No. 59-56479
BaFX・xNaX′: aEu ²⁺ [However, X and X′ are
Each is at least one of Cl, Br, and I, and x and a are each 0<x≦2,
and 0<a≦0.2], M〓 described in JP-A No. 59-56480
FX・xNaX′: yEu ²⁺ : zA [However, M〓 is Ba,
at least one alkaline earth metal selected from the group consisting of Sr, and Ca;
X′ is at least one kind of halogen selected from the group consisting of Cl, Br, and I;
is at least one transition metal selected from V, Cr, Mn, Fe, Co, and Ni; and
A phosphor ^represented by the composition formula: There M〓
FX・aM〓X′・bM′〓X″ ₂・cM〓X ₃・xA：
yEu ²⁺ [where M〓 is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; M〓 is Li, Na, K, Rb, and Cs
is at least one kind of alkali metal selected from the group consisting of; M′〓 is at least one divalent metal selected from the group consisting of Be and Mg;
M〓 is at least one kind of trivalent metal selected from the group consisting of Al, Ga, In, and Tl; A is a metal oxide; X is at least one kind selected from the group consisting of Cl, Br, and I. X′, X″, and X″ are at least one kind of halogen selected from the group consisting of F, Cl, Br, and I; and a is 0≦a≦2, and b is 0 ≦
b≦10 ^-2 , c is 0≦c≦10 ^-2 , and a+b+c≧
10 ^-6 ; x is 0<x≦0.5, y is 0<y≦0.2
A phosphor _represented by the composition ^formula M〓X ₂・aM〓
M〓 is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; X and X' are at least one kind of halogen selected from the group consisting of Cl, Br, and I, and ≠
X′; and a is 0.1≦a≦10.0, and x is 0<
x < 0.2], M〓FX・aM〓X′:xEu ²⁺ [However,
M〓 is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr and Ca; M〓
is at least one kind of alkali metal selected from the group consisting of Rb and Cs; X is at least one kind of halogen selected from the group consisting of Cl, Br and I; X′ consists of F, Cl, Br and I and a and x are 0≦a≦4.0 and 0≦x≦0.2, respectively. In addition, the M〓X _{2 ・}aM〓X' ₂ :xEu ²⁺ phosphor described in the above-mentioned Japanese Patent Application No. 193161/1987 contains additives as shown below. It may be contained in the following proportions per 1 mole of 〓X′ ₂ . bM〓X″ (however, M〓 is Rb and Cs
X″ is at least one halogen selected from the group consisting of F, Cl, Br and I, and b satisfies 0<b≦10.0); Gansho 59
−bKX″/cMgX described in specification No. 77225
₂・dM〓X′′′′′ ₃ (However, M〓 is Sc, Y, La, Gd
and at least one kind of trivalent metal selected from the group consisting of Lu, and X'', and b, c and d are 0≦b≦2.0, 0≦c, respectively
≦2.0, 0≦d≦2.0, and 2×10 ^-5 ≦b
+c+d); yB described in the specification of Japanese Patent Application No. 59-84356 (however, y is 2×10 ^-4 ≦y≦2
×10 ^-1 ); and bA described in Japanese Patent Application No. 59-84358 (where A is SiO ₂ and P ₂ O ₅
and b is ^10-4 ≦b≦2× ^10-1 ) Among the above-mentioned stimulable phosphors, divalent europium-activated alkaline earth Metal halide phosphors and rare earth element-activated rare earth oxyhalide phosphors are particularly preferred because they exhibit high-intensity stimulated luminescence. However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphors, but any phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light. It may be. Examples of binders for the phosphor layer include proteins such as gelatin, polysaccharides such as dextran, or natural polymeric substances such as gum arabic; and polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethylcellulose, and vinylidene chloride. - List binders represented by synthetic polymeric materials such as vinyl chloride copolymers, polyalkyl (meth)acrylates, vinyl chloride-vinyl acetate copolymers, polyurethanes, cellulose acetate butyrate, polyvinyl alcohol, linear polyesters, etc. I can do it. Particularly preferred among such binders are nitrocellulose, linear polyesters, polyalkyl (meth)acrylates, mixtures of nitrocellulose and linear polyesters, and mixtures of nitrocellulose and polyalkyl (meth)acrylates. be. Note that some of these binders may be crosslinked with a crosslinking agent. Next, the antistatic agent used in the present invention is an inorganic salt of a metal. By containing an inorganic metal salt on the surface side of the phosphor layer, charges accumulated on the surface can be prevented by movement (discharge) of charges due to surface conduction. That is, by reducing the surface electrical resistance of the substance, the generated charges can be easily discharged. Typical examples of metal inorganic salts used as antistatic agents in the present invention include LiCl, NaCl,
NaBr, NaI, _NaNO3 , _Na3PO4 , _CsI , _BaBr2 ,
Examples include inorganic salts of metals such as BaI ₂ , MgBr ₂ and AlBr ₃ . It should be noted that these metal inorganic salts may be in an anhydride state or in a state to which water of crystallization is added, as long as they are stable at room temperature. Among the above metal inorganic salts, preferred are:
LiCl, NaBr, NaI, _NaNO3 , _MgNr2 and
_AlBr3 . Furthermore, LiCl, NaBr, and MgBr ₂ are particularly preferred because they are uncolored and have high solubility in solvents such as water and alcohol. That is, since these metal halides are uncolored, they do not absorb excitation light, and because they are dissolved in the binder solution, they are highly dispersible on the surface of the resulting phosphor layer. The phosphor layer can be formed on the support, for example, by the following method. First, the above-mentioned stimulable phosphor and binder are added to a suitable solvent and thoroughly mixed to prepare a coating solution (2) in which phosphor particles are uniformly dispersed in the binder solution. Examples of solvents for preparing coating solutions include:
methanol, ethanol, n-propanol, n
- lower alcohols such as butanol; chlorine-containing hydrocarbons such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; Ethers such as dioxane, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether; and mixtures thereof may be mentioned. The mixing ratio of the binder and the stimulable phosphor in the coating solution varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, etc., but in general, the mixing ratio of the binder and the stimulable phosphor is , 1:1 to 1:100 (weight ratio), and particularly preferably 1:8 to 1:40 (weight ratio). Note that the coating liquid () contains a dispersant to improve the dispersibility of the phosphor in the coating liquid, and a dispersant to improve the bonding force between the binder and the phosphor in the phosphor layer after formation. Various additives such as plasticizers may be mixed. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, lipophilic surfactants, and the like. Examples of plasticizers include phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, and diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; and ethyl phthalyl ethyl glycolate and butyl phthalyl butyl glycolate. Glycolic acid esters; and polyesters of polyethylene glycol and aliphatic dibasic acids, such as polyesters of triethylene glycol and adipic acid and polyesters of diethylene glycol and succinic acid. Furthermore, in order to improve image sharpness, the coating liquid has an average reflectance in the excitation light wavelength region of the stimulable phosphor that is higher than the average reflectance in the stimulated emission wavelength region of the stimulable phosphor. Colorants with small reflective properties may also be included. As such a coloring agent, for example, JP-A-55-
Colorants such as those disclosed in Japanese Patent Publication No. 163500 and Japanese Unexamined Patent Publication No. 57-96300 can be mentioned. Alternatively, the coating liquid may contain a white powder as described in JP-A-55-146447 for the purpose of improving the sharpness of the image. Separately from the coating liquid (2), the antistatic agent is dissolved or dispersed in a suitable solvent, and then a binder is added and thoroughly mixed to prepare a coating liquid (2) containing the antistatic agent. In addition to the binders used in the coating liquid (2) for forming the phosphor layer, examples of binders for the coating liquid (2) include cellulose derivatives, polyvinyl chloride, polyvinylidene chloride, polyvinyl formal, melamine, and phenolic resins. , epoxy resin, etc. The binder used in the coating solution () may be the same as the binder used in the coating solution () or may be completely different. However, the binder needs to be compatible with the binder in the coating solution (). In addition, from the point of view of scratch resistance on the surface of the radiation image conversion panel, coating liquid ()
Preferably, the binder is relatively hard;
On the other hand, from the viewpoint of mechanical strength and the like, it is preferable that the binder of the coating liquid (2) is the same as that of the coating liquid (2). The ratio of the antistatic agent to the binder solution in the coating solution () varies depending on the type of antistatic agent, the type of binder, and the structure of the panel to be manufactured, but in general, the ratio of the antistatic agent to the binder solution It is selected from the range of 0.1 to 20% by weight, particularly preferably from the range of 0.5 to 5% by weight based on the amount used. Further, as the solvent, the above-mentioned solvents can be used, but from the viewpoint of dispersibility of the antistatic agent in the phosphor layer, it is preferable to use a solvent that can dissolve the metal inorganic salt that is the antistatic agent. . Also,
The solvent of the coating liquid (2) may be the same as the solvent used in the coating liquid (2), or may be different. However, since it is necessary to match the drying speed of the coating film formed by layering coating solutions () and (), it is desirable to use solvents that are compatible with each other. Furthermore, the coating liquid (2) may contain various dispersants, plasticizers, colorants, etc. used in the coating liquid (2). The coating solution () prepared as described above and the coating solution () are coated uniformly and simultaneously on the surface of the support by placing the coating solution () on the support side, so that the coating solution containing the antistatic agent can be coated uniformly on the surface of the support. A coating film of the coating liquid is formed so that the applied part is on the panel surface side. This coating operation can be performed, for example, by using a dual hopper type coating device. The coating amount of coating liquid () and coating liquid () are as follows:
Although it varies depending on the characteristics of the intended radiation image conversion panel, the viscosity of the coating liquid, the mixing ratio of binder and phosphor, etc., it is usually selected from the range of 100:1 to 1:1 (volume ratio). Preferably it is in the range of 10:1 to 1:1. Additionally, the ratio of antistatic agent to binder throughout both coating solutions is generally 0.03 to 6% by weight.
It is particularly preferably selected from the range of 0.1 to 2% by weight. Next, the formed coating film of the coating liquid ( ) on the support side and the coating film of the coating liquid ( ) formed thereon are gradually heated and dried to form a phosphor layer on the support. complete. The phosphor layer formed in this way consists of a part on the support side where the phosphor particles exist in a dispersed state, and a part on the panel surface side that contains an antistatic agent. Even when observed, there is no boundary between the two parts, and a single phosphor layer is formed. Furthermore, the phosphor layer does not necessarily need to be formed by directly applying a coating liquid onto a support as described above; for example, the coating liquid is separately applied onto a flat sheet such as a glass plate, metal plate, or plastic sheet. After forming a phosphor layer by simultaneous multilayer coating as described above, the phosphor layer may be bonded to the support by pressing it onto the support, or by using an adhesive. In this case, apply liquid ()
Depending on the desired characteristics of the radiation image conversion panel, coating conditions, etc., either of the coating liquid (2) and (2) may be placed on the plane sheet side for multilayer coating. The thickness of the phosphor layer varies depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, the mixing ratio of the binder and the phosphor, and is usually 20 μm to 1 mm. However, this layer thickness is 50 to 500μm
It is preferable that In addition, the part containing the antistatic agent on the panel surface side is about 3 to 20 μm.
It is preferable to have a thickness of m, and the ratio of the portion where the stimulable phosphor is present on the support side to the portion containing the antistatic agent on the panel surface side is 100:1 to 100:1 in terms of layer thickness (average). Preferably, the ratio is in the range of 5:1. The support used in the present invention can be arbitrarily selected from various materials used as supports for intensifying screens in conventional radiography methods or materials known as supports for radiation image conversion panels. . Examples of such materials include films of plastic materials such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate, metal sheets such as aluminum foil, aluminum alloy foil, regular paper, baryta paper, resins, etc. Examples include coated paper, pigment paper containing pigments such as titanium dioxide, and paper sized with polyvinyl alcohol. However, when considering the characteristics and handling of the radiation image conversion panel as an information recording material,
A particularly preferred material for the support in the present invention is plastic film. This plastic film may be kneaded with a light-absorbing substance such as carbon black, or may be kneaded with a light-reflecting substance such as titanium dioxide.
The former is a support suitable for a high sharpness type radiation image conversion panel, and the latter is a support suitable for a high sensitivity type radiation image conversion panel. In known radiation image conversion panels, a phosphor layer is provided in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymeric substance such as gelatin is coated on the surface of the support on the side to be coated to form an adhesion imparting layer, or a light reflective layer made of a light reflective material such as titanium dioxide, or a light absorbing material such as carbon black. Providing a light absorption layer is also practiced. The support used in the present invention can also be provided with these various layers, and their configurations can be arbitrarily selected depending on the purpose, use, etc. of the desired radiation image storage panel. Furthermore, as described in Japanese Patent Application Laid-Open No. 58-200200, in order to improve the sharpness of the obtained image, the surface of the support on the phosphor layer side (the surface of the support on the phosphor layer side) When an adhesion-imparting layer, a light-reflecting layer, a light-absorbing layer, etc. are provided, fine irregularities may be uniformly formed on the surface (meaning the surface thereof). Next, Examples and Comparative Examples of the present invention will be described.
However, these examples do not limit the invention. In each of the following examples, "parts" represent "parts by weight" unless otherwise specified. Example 1 A polyurethane resin solution was prepared by dissolving a polyurethane resin (Desmolak 4125, manufactured by Sumitomo Bayer Urethane Co., Ltd.) in a mixed solvent of methyl ethyl ketone and isopropyl alcohol. Further, a nitrocellulose solution was prepared by dissolving nitrocellulose (RS-120, manufactured by Daicel Chemical Industries, Ltd.) in a mixed solvent of methyl ethyl ketone and isopropyl alcohol. Particles of photostimulable divalent europium-activated fluorobromide phosphor (BaFBr: Eu ²⁺ ) are dispersed in a mixed solvent of methyl ethyl ketone and isopropyl alcohol, and the above polyurethane resin solution and nitrocellulose solution are added to this dispersion. In addition, ultramarine blue (pigment; PB-100, manufactured by Daiichi Kasei Kogyo Co., Ltd.) and tricresyl phosphate were added and dissolved using a propeller mixer to prepare a dispersion containing the phosphor [coating solution ()]. did. Next, sodium bromide (NaBr) as an antistatic agent was added to the mixed solvent of methyl ethyl ketone, isopropyl alcohol, and these and sufficiently dissolved, and then a polyurethane resin (Desmolak 4125, manufactured by Sumitomo Bayer Urethane Co., Ltd.) was added to this solution. Cellulose (RS-120, manufactured by Daicel Chemical Industries, Ltd.)
and tricresyl phosphate, and mix using a propeller mixer to form a binder solution [coating solution ()].
was prepared. The compositions of coating liquid () and coating liquid () are shown below. Composition of coating solution () BaFBr: Eu ²⁺ phosphor 800 parts Polyurethane resin 83.1 parts Nitrocellulose 52 parts Group Blue 0.052 parts Tricresyl phosphate 2.6 parts Methyl ethyl ketone 204.6 parts Isopropyl alcohol 39.5 parts Composition of coating solution () Polyurethane resin 145 parts Nitrocellulose 9.1 parts Tricresyl phosphate 4.5 parts Sodium bromide 1.4 parts Methyl ethyl ketone 287.5 parts Isopropyl alcohol 51.6 parts Next, a carbon-mixed polyethylene terephthalate sheet (support, thickness: 250 μm) was placed horizontally on a glass plate, and the coating solution () and The coating solution (2) was simultaneously coated onto the support in multiple layers using a double hopper type coating device as shown in FIG. That is, in FIG. 1, the coating liquid ( ) was injected into the right introduction part 2 of the dual hopper type coating device 1 , and the coating liquid ( ) was introduced into the left introduction part 3 . The lengths of the lower openings of introduction parts 2 and 3 are respectively
They were 0.500mm and 0.150mm. While moving the glass plate 4 on which the support 5 is placed at a speed of 1.0 m/min in the direction of the arrow 8, the coating liquids () and () are simultaneously coated in layers on the support 5 from the lower opening. A coating film 6 of coating liquid ( ) and a coating film 7 of coating liquid ( ) were formed. After coating, the support on which the coating film had been formed was placed in a dryer, and the temperature inside the dryer was gradually raised from 25°C to 100°C to dry the coating film for 50 minutes. In this way, the layer thickness of the part on the support side where the stimulable phosphor is present is about 340 μm, and the layer thickness of the part containing the antistatic agent on the panel surface side is about 340 μm.
A 7 μm phosphor layer was formed to produce a radiation image storage panel composed of a support and a phosphor layer. Comparative Example 1 A radiation image conversion panel comprising a support and a phosphor layer was produced in the same manner as in Example 1 except that sodium bromide was not added to the coating solution (2). Comparative Example 2 In Example 1, using only the coating liquid (),
A phosphor layer with a layer thickness of about 340 μm was coated on a support by the same method as in Example 1, except that only the introduction part 2 (length of the lower opening: 0.500 mm) of the dual hopper type coating device was used. formed a layer. Next, a transparent polyethylene terephthalate film (protective film, thickness: 7 μm,
A transparent protective film is attached by placing the polyester adhesive (with the adhesive layer facing down) using a heated roll at 90 to 100°C, and attaching a transparent protective film to the support and phosphor. A radiation image storage panel was produced consisting of a layer and a transparent overcoat. Each of the radiation image storage panels obtained in Example 1, Comparative Example 1, and Comparative Example 2 was evaluated by the surface resistance test and transportability test described below. (1) Surface resistance test Circular electrode (P-601 type, manufactured by Kawaguchi Electric Seisakusho Co., Ltd.)
A radiation image conversion panel cut into a size of 110 mm x 110 mm was placed on a circular electrode, and a voltage was applied to the panel. The electrical resistance of the surface was measured. The measurement was performed at a temperature of 23℃ and humidity of 50%.
It was conducted under RH conditions. (2) Transportability Test By transporting the radiation image conversion panel within the radiation image recording/reading device, the cycle of movement and stacking was repeated 100 times, and the number of times the two panels were transported simultaneously was measured. The results obtained are shown in Table 1.

[Table] As is clear from Table 1, a radiation image storage panel containing the antistatic agent of the present invention (Example 1)
has a significantly lower surface resistance and prevents charging.
As a result, the double panel conveyance phenomenon did not occur at all.
We were able to perform smooth transport operations. On the other hand, a radiation image storage panel that does not contain an antistatic agent (Comparative Example 1) and a radiation image storage panel that does not contain an antistatic agent and has a separate protective layer (Comparative Example 2) have a large surface resistance. , Two panels were transported 3 to 4 times. Examples 2 to 9 In Example 1, the support and fluorescence A radiation image storage panel constructed from body layers was manufactured. The ratio of the metal inorganic salt to the binder in the coating liquid (2) was 2% by weight in the case of sodium chloride, and 3% by weight in all other cases.

[Table] Each of the radiation image conversion panels obtained in Examples 2 to 9 was evaluated by the above-mentioned surface resistance test. The results obtained are shown in Table 3.

[Table] As is clear from Table 3, radiation image storage panels (Examples 2 to 3) containing the antistatic agent of the present invention
In Example 9), the surface resistance was significantly lowered and charging properties could be prevented. Example 10 In Example 1, polyacrylic resin (Criscoat P-1018GS, manufactured by Dainippon Ink and Chemicals Co., Ltd., and Paraloid B-66, Rohm and
(manufactured by Hass Corp.), further adding aliphatic polyisocyanate (Sumidyur N-75, manufactured by Sumitomo Bayer Urethane Co., Ltd.) as a plasticizer, and not using ultramarine as a coloring agent or isopropyl alcohol as a solvent. and polyacrylic resin (Dyanal BR-102, manufactured by Mitsubishi Rayon Co., Ltd.) instead of polyurethane resin as a binder in the coating solution (), lithium chloride (LiCl) instead of sodium bromide as an antistatic agent, and a plasticizer. Coating solutions () and () having the following compositions were prepared by carrying out the same treatment as in Example 1, except that tributyl phosphate was used instead of tricresyl phosphate, and isopropyl alcohol was not used. . Composition of coating solution () BaFBr: Eu ²⁺ phosphor 800 parts Polyacrylic resin (Criscoat) 56.1 parts Polyacrylic resin (Paraloid) 9.1 parts Nitrocellulose 3.7 parts Aliphatic polyisocyanate 1.8 parts Tricresyl phosphate 1.3 parts Methyl ethyl ketone 230 parts Coating Composition of liquid () Polyacrylic resin (Dianal) 65.9 parts Nitrocellulose 8.1 parts Tributyl phosphate 7.4 parts Lithium chloride 1.6 parts Methyl ethyl ketone 412 parts Next, the method of Example 1 was followed except that the above coating liquids () and () were used. By performing the same treatment as above, the thickness of the layer on the support side where the stimulable phosphor is present is approximately 348 μm, and the layer thickness of the portion containing the antistatic agent on the panel surface side is approximately 7 μm. A phosphor layer was formed to produce a radiation image storage panel composed of a support and a phosphor layer. Comparative Example 3 In Comparative Example 1, the same treatment as in Comparative Example 1 was carried out except that lithium chloride was not used in the coating solution () of Example 10. An image conversion panel was manufactured. Each of the radiation image storage panels obtained in Example 10 and Comparative Example 3 was evaluated by the same tests as above.
The results obtained are shown in Table 4.

[Table] As is clear from Table 4, the radiation image storage panel containing the antistatic agent of the present invention (Example 10)
Compared to the radiation image storage panel that does not contain an antistatic agent (Comparative Example 3), the surface resistance is significantly reduced and charging is prevented, and as a result, the phenomenon of double-panel conveyance in the conveyance system does not occur. I was able to perform the operation smoothly.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a dual hopper type coating device, which is an example of a coating device used in the method of manufacturing a radiation image storage panel of the present invention. 1: Double hopper type coating device, 2: Right side introduction section [coating liquid ()], 3: Left side introduction section [coating liquid ()], 4: Glass plate, 5: Support, 6: Coating liquid () 7: Coating film of coating liquid (), 8: Arrow.

Claims (1)

[Scope of Claims] 1. A radiation image conversion panel comprising a support and a phosphor layer provided on the support and made of a binder containing and supporting a stimulable phosphor, wherein the phosphor layer is on the support side. It is composed of a part where the stimulable phosphor is present and a part where the stimulable phosphor is not present on the panel surface side, and there is no interface between the two parts, and the stimulable phosphor is not present. A radiation image conversion panel characterized in that a portion thereof contains an antistatic agent made of an inorganic metal salt. 2 The antistatic agent is LiCl, NaCl, NaBr, NaI,
_NaNO3 , _Na3PO4 , CsI, _{MgBr2 , BaBr2} , _BaI2
The radiation image storage panel according to claim 1, which is at least one metal inorganic salt selected from the group consisting of AlBr ₃ and AlBr 3 . 3 The antistatic agent is LiCl, NaI, NaBr, MgBr ₂
The radiation image storage panel according to claim 1, which is at least one metal inorganic salt selected from the group consisting of AlBr ₃ and AlBr 3 . 4. The radiation image storage panel according to claim 1, wherein the antistatic agent is contained in the phosphor layer in an amount of 0.03 to 6% by weight based on the amount of the binder. 5 The ratio of the average thickness of the part where the stimulable phosphor is present on the support side and the average thickness of the part where the stimulable phosphor is not present on the panel surface side is 100:1 to 5:1.
A radiation image conversion panel according to claim 1 falling within the scope of claim 1. 6. Claim 1, wherein the composition of the binder in the phosphor layer is the same in the part on the support side where the stimulable phosphor is present and the part on the panel surface side where the stimulable phosphor is not present. The radiographic image conversion panel described. 7. Claim 1, wherein the composition of the binder in the phosphor layer is different between the part on the support side where the stimulable phosphor is present and the part on the panel surface side where the stimulable phosphor is not present. The radiographic image conversion panel described. 8. Prepare a binder solution () containing a stimulable phosphor dispersed therein and a binder solution () containing an antistatic agent made of an inorganic salt of a metal using mutually compatible solvents, A method for producing a radiation image storage panel, characterized in that a binder solution () containing a stimulable phosphor dispersed therein is simultaneously coated in layers on the surface of the support so that the binder solution () is on the support side. 9 The antistatic agent is LiCl, NaCl, NaBr, NaI,
_NaNO3 , _Na3PO4 , CsI, _{MgBr2 , BaBr2} , _BaI2
9. The method for producing a radiation image storage panel according to claim 8, wherein the at least one metal inorganic salt is selected from the group consisting of AlBr ₃ and AlBr 3 . 10 The antistatic agent is LiCl, NaI, NaBr,
10. The method for producing a radiation image conversion panel according to claim 9, which is at least one metal inorganic salt selected from the group consisting of MgBr ₂ and AlBr ₃ . 11. The method for producing a radiation image storage panel according to claim 8, wherein the antistatic agent is contained in the binder solution () in an amount of 0.1 to 20% by weight based on the amount of the binder. 12 The volume ratio of the coating amount of the binder solution () formed by dispersing the stimulable phosphor and the coating amount of the binder solution () containing the antistatic agent is 100:1 to 1:
1. A method for manufacturing a radiation image conversion panel according to claim 8. 13. The binder solution according to claim 8, wherein the binder solution in which the stimulable phosphor is dispersed and the binder solution in the binder solution containing an antistatic agent () have the same composition. A method for manufacturing a radiation image conversion panel. 14. The binder solution according to claim 8, wherein the binder solution in which the stimulable phosphor is dispersed and the binder solution in which the antistatic agent is contained have different compositions. A method for manufacturing a radiation image conversion panel. 15 Prepare a binder solution () containing a stimulable phosphor dispersed therein and a binder solution () containing an antistatic agent made of an inorganic salt of a metal using mutually compatible solvents, A method for producing a radiation image conversion panel, which comprises: forming a phosphor layer by simultaneously coating a flat sheet in multiple layers, and then separating the phosphor layer from the sheet and attaching it to a support. 16 Antistatic agents include LiCl, NaCl, NaBr, NaI,
_NaNO3 , _Na3PO4 , CsI, _{MgBr2 , BaBr2} , _BaI2
16. The method for producing a radiation image storage panel according to claim 15, which is at least one metal inorganic salt selected from the group consisting of AlBr3 and _AlBr3 . 17 The antistatic agent is LiCl, NaI, NaBr,
16. The method for producing a radiation image conversion panel according to claim 15, wherein the method is at least one metal inorganic salt selected from the group consisting of MgBr ₂ and AlBr ₃ . 18. The method for producing a radiation image storage panel according to claim 15, wherein the antistatic agent is contained in the binder solution in an amount of 0.1 to 20% by weight based on the amount of the binder. 19 The volume ratio of the coating amount of the binder solution () formed by dispersing the stimulable phosphor to the coating amount of the binder solution () containing the antistatic agent is 100:1 to 1:
1. A method for manufacturing a radiation image conversion panel according to claim 15. 20. The binder solution according to claim 15, wherein the binder solution in which the stimulable phosphor is dispersed and the binder solution in which the antistatic agent is contained have the same composition. A method for manufacturing a radiation image conversion panel. 21. The binder solution according to claim 15, wherein the binder solution in which the stimulable phosphor is dispersed and the binder solution in which the antistatic agent is contained have different compositions. A method for manufacturing a radiation image conversion panel.