JPH0521439B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a method for manufacturing a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor. More specifically, the present invention includes:
The present invention relates to a method for manufacturing a radiation image storage panel having a support, a phosphor layer made of a stimulable phosphor, and a protective film in this order.

[Technical Background of the Invention and Prior Art] As a method for obtaining radiation images as images, the so-called radiography method has conventionally used a combination of a radiographic film having an emulsion layer made of a silver salt photosensitive material and an intensifying screen. It's being used. 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 radiation image conversion method described above has a basic structure consisting of a support and a phosphor layer provided on one side of the support. In addition,
Generally, a transparent protective film is provided on the surface of the phosphor layer opposite to the support (the surface not facing the support), and the phosphor layer is protected from chemical alteration or physical damage. Protects from strong impacts.

The phosphor layer consists of a stimulable phosphor and a binder that contains and supports the stimulable phosphor in a dispersed state. After absorbing radiation such as X-rays, the stimulable phosphor absorbs radiation such as visible light and infrared rays. It has the property of emitting light (stimulated luminescence) when irradiated with electromagnetic waves (excitation light). Therefore, the radiation transmitted through the subject or emitted from the subject is absorbed by the phosphor layer of the radiation image conversion panel in proportion to the amount of radiation, and the radiation of the subject or subject is absorbed on the radiation image conversion panel. An image is formed as a cumulative image of radiation energy. This accumulated image can be emitted as stimulated luminescence by time-series excitation with the electromagnetic waves mentioned above, and by reading this stimulated luminescence photoelectrically and converting it into an electrical signal, the accumulated image of radiation energy can be imaged. It becomes possible to convert into

The radiation image conversion method is a very advantageous image forming method as described above, but the radiation image conversion panel used in this method is also highly sensitive and similar to the intensifying screen used in the conventional radiography method described above. It is desired that the image quality (sharpness, graininess, etc.) of the image quality is good.

Until now, protective films have generally been applied to radiation image storage panels by applying a solution of a transparent polymeric substance dissolved in an appropriate solvent to the surface of an already formed phosphor layer, or by forming a protective film separately. This is done by bonding a transparent thin film using an adhesive or the like.

When forming a protective film on the phosphor layer by coating, the type of solvent in the coating solution, the combination of the polymer substance in the coating solution and the binder in the phosphor layer, and the phosphor particles in the phosphor layer are important. Since the adhesion strength between the phosphor layer and the protective film varies greatly depending on the content of was. Furthermore, although radiation image conversion panels are generally used repeatedly, if a protective film is attached to the phosphor layer via an adhesive layer, the adhesive layer may be damaged mechanically or It was susceptible to thermal deterioration, and as a result, the protective film tended to peel off. That is, there was a problem in that the adhesion strength between the phosphor layer and the protective film was insufficient, and the panel lacked durability when used repeatedly.

In addition, light (excitation light) is generally easily scattered at the interface between each layer, and when a protective film is attached to the phosphor layer via an adhesive layer, the phosphor layer, adhesive layer, and protective film are Since light scattering occurs at the interface between each layer, the quality of the resulting image tends to deteriorate.

Furthermore, the scattering of stimulated luminescence light at each of the above-mentioned interfaces reduces the efficiency of reading out light from the panel surface (protective film surface), thereby contributing to a decrease in the sensitivity of the radiation image conversion panel.

[Summary of the Invention] An object of the present invention is to provide a method for manufacturing a radiation image storage panel with improved mechanical strength.

Another object of the present invention is to provide a method for manufacturing a radiation image conversion panel that provides images with improved image quality.

A further object of the present invention is to provide a method for manufacturing a radiation image storage panel with improved sensitivity.

That is, the present invention provides: (1) a binder solution in which a stimulable phosphor is dispersed; and a binder solution that does not contain a stimulable phosphor, and which is a binder solution containing a stimulable phosphor; A binder solution consisting of an incompatible binder is simultaneously coated on the surface of the support in a layered manner such that the binder solution containing the stimulable phosphor dispersed therein is on the support side, thereby forming a phosphor layer and a protective layer. A method for producing a radiation image storage panel of the present invention, which is characterized in that it forms a film, and (2) a binder solution in which a stimulable phosphor is dispersed, and a binder solution that does not contain a stimulable phosphor. A binder solution consisting of a binder that is incompatible with the binder contained in the binder solution is simultaneously coated in layers on a flat sheet to form a phosphor layer and a protective film. Provided is a method for producing a radiation image storage panel according to the present invention, characterized in that a phosphor layer and a protective film are separated from the sheet and attached on a support.

[Effects of the Invention] The present invention improves the mechanical strength and sensitivity of a radiation image conversion panel by simultaneously forming a phosphor layer and a protective film on a support by multilayer coating.
Furthermore, it is possible to realize remarkable improvements in various characteristics such as improvement in the image quality of images obtained by the panel.

Conventionally, in general, a binder solution (coating solution) containing dispersed phosphor particles is applied onto a support by a conventional coating method and dried to form a phosphor layer, and then the surface of this phosphor layer is coated. A protective film has been attached by attaching a transparent thin film made of a polymeric material such as polyethylene terephthalate to the surface using an adhesive. In the present invention, a coating solution in which phosphor particles are dispersed and a binder solution containing no phosphor particles are placed on the support side and simultaneously coated on the support (or on another flat sheet). (2) By applying multilayer coating, the phosphor layer and the protective film can be formed simultaneously in a single coating operation. Therefore, there is no need to further provide a protective film on the phosphor layer as in the conventional case, and the manufacturing process of the radiation image storage panel can be simplified.

In addition, in the manufacturing method of the present invention, both the phosphor layer and the coating film for forming the protective film are dried simultaneously.
As a result, the adhesion strength between the protective film and the phosphor layer can be increased compared to the conventional method, and problems such as peeling of the protective film from the phosphor layer due to deterioration of the adhesive layer do not occur.

Furthermore, since the radiation image conversion panel manufactured according to the present invention does not have an interface formed by attaching an adhesive layer, scattering of excitation light can be reduced compared to conventional panels, and sharpness and Images with improved image quality such as graininess can be obtained.
At the same time, since there is no scattering of fluorescence at the interface, it is possible to improve image quality and increase sensitivity.

In the past, when attaching (laminating) a protective film, dust tended to adhere to the surface of the phosphor layer, requiring caution in the attaching operation, but with the present invention, such problems do not occur. .
This also makes it easy to obtain high-quality images.

[Structure of the Invention] A radiation image conversion panel having the preferable characteristics as described above can be manufactured, for example, by the manufacturing method of the present invention as described below.

That is, the formation of the phosphor layer and the protective film, which are the characteristic requirements of the present invention, can be performed, for example, as follows.

First, in order to form a phosphor layer, a coating liquid () in which stimulable phosphor particles are uniformly dispersed in a binder solution is prepared.

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 point of view, it has a wavelength of 400~
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 stimulable phosphors used in radiation image storage panels 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
(Ba _1-xy , Mg _x , Ca _y )FX: aEu ²⁺ (where X
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
is 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 ,
At least one of GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , Ln is Eu, Tb, Ce,
At least one of Tm, Dy, Pr, Ho, Nd, Yb, Er, Sm, and Gd, X is at least one of Cl, Br, and I, and x and y are each 5×10 ^-5 ≦x≦0.5 and 0<y
≦0.2], which is described in Japanese Patent Application Laid-open No. 116777/1982 (Ba _1-x , M〓 _x ) F ₂・aBaX ₂ : yEu, zA
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 ,
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<z≦5×10 ^-1 ], M
OX: xCe [However, M〓 is Pr, Nd, Pm, Sm,
At least one kind of 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 is 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⁺ [However, X is at least one halogen selected from the group consisting of Cl, Br, and I; A is a calcined product of a tetrafluoroboric acid compound; 10 ^-6 ≦x≦
0.1, y is 0<y≦0.1] A phosphor is described in Japanese Patent Application Laid-open No. 1983-47289.
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], etc. can be mentioned.

Among the above-mentioned photostimulable phosphors, divalent europium-activated alkaline earth metal fluorohalide-based phosphors and rare earth element-activated rare earth oxyhalide-based 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 these binders may be crosslinked with a crosslinking agent.

Examples of solvents for preparing coating solutions include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; chlorine-containing hydrocarbons such as methylene chloride and ethylene chloride; and 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 dioxine, ethylene glycol monoethyl ether, and ethylene glycol monomethyl ether; and mixtures thereof.

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).

The coating liquid also 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 Application Laid-Open No. 163500 and Japanese Unexamined Patent Publication No. 57-96300 can be mentioned. Alternatively, for the purpose of improving the sharpness of the image, a white powder as described in JP-A-55-146447 may be contained after coating.

Next, in order to form a protective film, a coating solution (2) is prepared in which only the binder is dissolved in a suitable solvent.

As the binder, in addition to the binder used in the coating liquid () for forming the phosphor layer, cellulose derivatives, polyvinyl chloride, polyvinylidene chloride, polyvinyl formal, melamine, phenolic resin, epoxy resin, etc. can be mentioned. However, in order to form a protective film at the same time as the phosphor layer through the simultaneous multilayer coating of the present invention, the binder used in the coating solution () must be incompatible with the binder used in the coating solution (). Must be a binding agent. Further, from the viewpoint of scratch resistance on the surface of the radiation image storage panel, it is preferable that the binder of the coating liquid (2) be relatively hard.

As the solvent, the solvent used in the above-mentioned coating liquid (2) can be used, and it may be the same as or different from the solvent in the coating liquid (2). However, it is desirable to match the drying speed of the coating film formed by layering the coating solutions () and (), and for this purpose, 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).

Next, the coating liquid () prepared as described above and the coating liquid (2) are placed on the support side and coated uniformly on the surface of the support in multiple layers at the same time. Forms a coating film.
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.

After simultaneous multilayer coating, apply the coating solution on the support side ()
The coating film and the coating film of the coating liquid (2) formed thereon are gradually heated and dried to complete the formation of the phosphor layer and the protective film on the support.
In this way, on the support, there is a phosphor layer made of a binder that contains and supports the phosphor particles in a dispersed state on the support side, and a protective film made of a binder that does not contain phosphor particles provided on top of the phosphor layer. is formed.

The phosphor layer and protective film do not necessarily need to be formed by directly applying a coating solution onto the support as described above; for example, the coating solution is separately applied onto a flat sheet such as a glass plate, metal plate, or plastic sheet. After forming a phosphor layer and a protective film by simultaneous multilayer coating as described above, this is pressed onto a support, or by using an adhesive, the support, phosphor layer, and protective film are bonded together. You may also join them. In this case, coating liquid () and coating liquid ()
Depending on the desired characteristics of the radiation image storage panel, coating conditions, etc., either layer 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, the thickness of this layer is preferably 50 to 500 μm. Further, the thickness of the protective film is preferably about 3 to 20 μm. Generally, the ratio of the thickness of the phosphor layer to the thickness of the protective film is 100:1 to 100:1.
A range of 5:1 is preferred.

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, resin. 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.

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] Polyacrylic resin A (Criscoat P-
1018GS, manufactured by Dainippon Ink and Chemicals Co., Ltd.) and polyacrylic resin B (Dyanal BR-107, manufactured by Mitsubishi Rayon Co., Ltd.) were dissolved in methyl ethyl ketone to prepare a polyacrylic resin solution. Also, nitrocellulose (RS-120, manufactured by Daicel Chemical Industries, Ltd.)
A nitrocellulose solution was prepared by dissolving in methyl ethyl ketone.

After dispersing particles of photostimulable divalent europium-activated barium fluoride bromide phosphor (BaFBr: Eu ²⁺ ) in methyl ethyl ketone, the above polyacrylic resin solution and nitrocellulose solution were added to this dispersion, and ultramarine ( Pigment; PB-100 (manufactured by Daiichi Kasei Kogyo Co., Ltd.) and tricresyl phosphate were added, and a coating liquid () in which the phosphor was uniformly dispersed was prepared using a propeller mixer.

Separately, polyurethane resin (Pandex T-
5275M, manufactured by Dainippon Ink & Chemicals Co., Ltd.), vinyl chloride/vinyl acetate copolymer (UCAR Solution)
Vinyl VYHH (manufactured by Union Carbide Corp.) and triphenyl phosphate were added to methyl ethyl ketone and mixed uniformly using a propeller mixer to prepare a coating solution (). The compositions of coating liquid () and coating liquid () are shown below. Composition of coating liquid () BaFBr: Eu ²⁺ phosphor 900 parts Polyacrylic resin A 67.5 parts Polyacrylic resin B 10.5 parts Nitrocellulose 4.5 parts Tricresyl phosphate 1.5 parts Ultramarine 0.0585 parts Methyl ethyl ketone 257 parts Composition of coating liquid () Polyurethane resin 14 Parts Vinyl chloride/vinyl acetate copolymer 24.8 parts Triphenyl phosphate 1.2 parts Methyl ethyl ketone 360 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
0.500mm and 0.150mm. While moving the glass plate 4 on which the support 5 is placed in the direction of the arrow 8 at a speed of 1.0 m/min, apply the coating liquid () from the lower opening.
and () were simultaneously coated in layers on a support 5 to form a coating film 6 of coating liquid () and a coating film 7 of coating liquid ().

After coating, the support with the coated film is placed in a dryer, and the temperature inside the dryer is set to 250°C.
The temperature was gradually increased from 100°C to 100°C to dry the coating film for 50 minutes. In this way, a radiation image storage panel composed of a support, a phosphor layer, and a transparent protective film was manufactured.

From the cross-sectional photograph obtained using a scanning electron microscope of the phosphor layer of this radiation image conversion panel,
It was clear that a phosphor layer containing phosphor particles at a high density and a transparent protective film were provided on the support with an interface. Further, from the cross-sectional photograph, the thickness of the phosphor layer was approximately 350 μm, and the thickness of the protective film was approximately 7 μm.

[Comparative Example 1] In Example 1, only the coating liquid () of Example 1 was used, and the introduction part 2 of the dual hopper type coating device was
A phosphor layer having a layer thickness of about 350 μm was formed on the support in the same manner as in Example 1, except that only the phosphor layer (length of the lower opening: 0.500 mm) was used.

Next, a transparent film (protective film, thickness:
7μm, coated with polyester adhesive) with the adhesive layer facing down and heated at 90 to 100℃.
A transparent protective film was attached by pressure bonding using a heating roll of 1, to produce a radiation image conversion panel composed of a support, a phosphor layer, and a transparent protective film.

Each radiation image storage panel obtained in Example 1 and Comparative Example 1 was evaluated by the following image sharpness test, image graininess test, sensitivity test, and adhesion strength test.

(1) Image sharpness test After irradiating the radiation image conversion panel with X-rays with a tube voltage of 80KVp through an MTF chart,
The phosphor particles are excited by scanning with Ne laser light (wavelength: 632.8 nm), and the stimulated luminescence emitted from the phosphor layer is detected by a receiver (photomultiplier tube with spectral sensitivity S-5).
It receives light and converts it into an electrical signal, which is then reproduced as an image by an image reproducing device and sent to a display device using MTF.
I got a picture of the chart. The modulation transfer function (MTF) was measured from the obtained image and expressed as an MTF value at a spatial frequency of 2 cycles/mm.

(2) Image graininess test The radiation image conversion panel was subjected to a tube voltage of 80KVp and a dose of
After irradiating 10 mR of X-rays, the phosphor particles are excited by scanning with He-Ne laser light (wavelength: 632.8 nm), and the stimulated luminescence emitted from the phosphor layer is detected using a receiver (spectral sensitivity S-5). The photomultiplier tube (photomultiplier tube) receives the light and converts it into an electrical signal, which is then recorded on ordinary photographic film using a film scanner. 5
Expressed as RMS value in books/mm.

(3) Sensitivity test After irradiating the radiation image conversion panel with X-rays with a tube voltage of 80KVp, a He-Ne laser beam (wavelength:
The sensitivity was measured by excitation at 632.8 nm).

(4) Adhesion strength test A radiation image conversion panel was cut to a width of 100 mm, and a cut was made at the interface between the phosphor layer and the protective film. Then, the adhesion strength was measured by pulling apart the protective film portion of the test piece thus prepared and the support and phosphor layer portions. The measurement was performed using a Tensilon universal tensile testing machine (UTM--20 manufactured by Toyo Baldwin) by pulling both parts in a direction perpendicular to each other (90° peeling) at a pulling speed of 10 mm/min. The adhesion strength was expressed as the force F (g/cm) acting when the membrane part was peeled off by 10 mm.

The results obtained are shown in Table 1.

Table 1 Example 1 Comparative Example 1 Sharpness 36.8% 35.5% Graininess 0.65×10 ^-2 0.70×10 ^-2 Relative sensitivity 127 115 Adhesion strength 130 g/cm 70 g/cm As is clear from Table 1, the present invention The radiation image conversion panel (Example 1) according to the present invention has higher sensitivity than the conventional radiation image conversion panel (Comparative Example 1),
Gives images with excellent sharpness and graininess,
It was also excellent in adhesion strength.

[Example 2] In Example 1, polyester resin A (Vylon 300,
By performing the same treatment as in Example 1 except for using Toyobo Co., Ltd.) and polyester resin B (Vylon 200, Toyobo Co., Ltd.),
Coating solution () was prepared.

In addition, in Example 1, polyurethane resin (Nituporan 5120,
Nippon Polyurethane Industries Co., Ltd.) and polyacrylic resin (Almatex L1020, Mitsui Toatsu Chemical Co., Ltd.)
Example 1 except that tributyl phosphate was used instead of triphenyl phosphate as a plasticizer.
A coating liquid (2) was prepared by carrying out the same treatment as in the method described above. The compositions of coating liquids () and () are shown below. Composition of coating solution () BaFBr: Eu ²⁺ phosphor 900 parts Polyester resin A 19.8 parts Polyester resin B 5.1 parts Nitrocellulose 3.3 parts Tricresyl phosphate 1.8 parts Ultramarine 0.0585 parts Methyl ethyl ketone 233 parts Composition of coating solution () Polyurethane resin 57.6 parts Polyester Acrylic resin 28.5 parts Tributyl phosphate 1.44 parts Methyl ethyl ketone 312 parts Next, the support, phosphor layer and transparent protector were treated in the same manner as in Example 1 except for using the above coating solutions () and (). A radiation image conversion panel constructed from a membrane was manufactured.

From the cross-sectional photograph obtained using a scanning electron microscope of the phosphor layer of this radiation image conversion panel,
It was clear that a phosphor layer containing phosphor particles at a high density and a transparent protective film were provided on the support with an interface. Further, from the cross-sectional photograph, the thickness of the phosphor layer was approximately 348 μm, and the thickness of the protective film was approximately 7 μm.

[Comparative Example 2] In Comparative Example 1, a phosphor layer of the same thickness was formed on the support by performing the same treatment as in Comparative Example 1 except for using the coating liquid () of Example 2. .

Next, a protective film was attached by pressure in the same manner as in Comparative Example 1, thereby producing a radiation image storage panel composed of a support, a phosphor layer, and a transparent protective film.

Each of the radiation image conversion panels obtained in Example 2 and Comparative Example 2 was evaluated by the same tests as above.

The results obtained are shown in Table 2.

Table 2 Example 2 Comparative Example 2 Sharpness 34.5% 33.5% Graininess 0.60×10 ^-2 0.65×10 ^-2 Relative sensitivity 135 255 Adhesion strength 200 g/cm 100 g/cm As is clear from Table 2, the present invention The radiation image conversion panel (Example 2) according to the present invention has higher sensitivity than the conventional radiation image conversion panel (Comparative Example 2),
Gives images with excellent sharpness and graininess,
It was also excellent in adhesion strength.

[Example 3] In Example 1, polyurethane resin (desmolac) was used instead of polyacrylic resin as the binder.
4125, manufactured by Sumitomo Bayer Urethane Co., Ltd.), isopropyl alcohol in addition to methyl ethyl ketone as a solvent, and triphenyl phosphate instead of tricresyl phosphate as a plasticizer, but the same process as in Example 1 was carried out. The coating liquid () was prepared by performing the following steps.

In addition, in Example 1, polyacrylic resin (Paraloid A-
30, Rohm and Haas Corp.) and an aliphatic polyisocyanate (Sumidyur N-75, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and the method of Example 1 except that tricresyl phosphate was used instead of triphenyl phosphate as a plasticizer. A coating liquid () was prepared by performing the same treatment as above. The compositions of coating liquids () and () are shown below. Composition of coating solution () BaFBr: Eu ²⁺ phosphor 900 parts Polyurethane resin 75.6 parts Nitrocellulose 8.1 parts Triphenyl phosphate 3.0 parts Ultramarine 0.0585 parts Methyl ethyl ketone 259 parts Isopropyl alcohol 46 parts Composition of coating solution () Polyacrylic resin 48.4 parts Aliphatic Polyisocyanate 7.4 parts Tricresyl phosphate 8.1 parts Methyl ethyl ketone 336 parts Next, the support, phosphor layer and transparent protector were treated in the same manner as in Example 1 except for using the above coating solutions () and (). A radiation image conversion panel constructed from a membrane was manufactured.

From the cross-sectional photograph obtained using a scanning electron microscope of the phosphor layer of this radiation image conversion panel,
It was clear that a phosphor layer containing phosphor particles at a high density and a transparent protective film were provided on the support with an interface. Further, from the cross-sectional photograph, the thickness of the phosphor layer was approximately 350 μm, and the thickness of the protective film was approximately 7 μm.

[Comparative Example 3] In Comparative Example 1, a phosphor layer of the same thickness was formed on the support by performing the same treatment as in Comparative Example 1 except that the coating liquid () of Example 3 was used. did.

Next, a protective film was attached by pressure in the same manner as in Comparative Example 1, thereby producing a radiation image storage panel composed of a support, a phosphor layer, and a transparent protective film.

Each of the radiation image storage panels obtained in Example 3 and Comparative Example 3 was evaluated by the same tests as above.

The results obtained are shown in Table 3.

Table 3 Example 3 Comparative Example 3 Sharpness 36% 35% Graininess 0.75×10 ^-2 0.85×10 ^-2 Relative sensitivity 128 120 Adhesion strength 140 g/cm 90 g/cm As is clear from Table 3, the present invention The radiation image conversion panel (Example 3) according to the present invention has higher sensitivity than the conventional radiation image conversion panel (Comparative Example 3),
Gives images with excellent sharpness and graininess,
It was also excellent in adhesion strength.

[Brief explanation of drawings]

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. DESCRIPTION OF SYMBOLS 1...Double hopper type coating device, 2...Right side introduction part [coating liquid ()], 3...Left side introduction part [coating liquid ()], 4...Glass plate, 5...Support, 6 …
... Coating film of coating liquid (), 7... Coating film of coating liquid (), 8... Arrow.

Claims (1)

[Claims] 1. A binder solution in which a stimulable phosphor is dispersed, and a binder solution that does not contain a stimulable phosphor and is incompatible with the binder contained in the binder solution. A binder solution consisting of a soluble binder is simultaneously coated on the surface of the support in a layered manner such that the binder solution containing the stimulable phosphor dispersed therein is on the support side, thereby forming a phosphor layer and a protective film. 1. A method for manufacturing a radiation image conversion panel, comprising: forming a radiation image conversion panel. 2 The volume ratio of the applied amount of the binder solution formed by dispersing the above-mentioned stimulable phosphor to the applied amount of the binder solution not containing the stimulable phosphor is in the range of 100:1 to 1:1. Claim 1 characterized in that
2. Method for manufacturing the radiation image conversion panel described in Section 1. 3. The method according to claim 1, wherein the solvent in the binder solution in which the stimulable phosphor is dispersed and the binder solution not containing the stimulable phosphor are compatible with each other. A method for manufacturing a radiation image conversion panel. 4 The binder solution formed by dispersing the stimulable phosphor has an average reflectance in the excitation light wavelength range of the stimulable phosphor that is lower than an average reflectance in the stimulated emission wavelength range of the stimulable phosphor. 2. The method for producing a radiation image storage panel according to claim 1, wherein the radiation image storage panel contains a small coloring agent. 5. A binder solution containing a stimulable phosphor dispersed therein, and a binder solution that does not contain a stimulable phosphor and is incompatible with the binder contained in the binder solution. A phosphor layer and a protective film are formed by simultaneously coating a binder solution in multiple layers on a flat sheet, and then the phosphor layer and protective film are separated from the sheet and attached to a support. A method for manufacturing a radiation image conversion panel. 6 The volume ratio of the coating amount of the binder solution containing the above-mentioned stimulable phosphor dispersed therein and the coating amount of the binder solution not containing the stimulable phosphor is in the range of 100:1 to 1:1. Claim 5 is characterized in that
2. Method for manufacturing the radiation image conversion panel described in Section 1. 7. The method according to claim 5, wherein the solvent in the binder solution in which the stimulable phosphor is dispersed and the binder solution that does not contain the stimulable phosphor are compatible with each other. A method for manufacturing a radiation image conversion panel. 8 The binder solution formed by dispersing the above-mentioned stimulable phosphor has an average reflectance in the excitation light wavelength region of the stimulable phosphor that is lower than an average reflectance in the stimulated emission wavelength region of the stimulable phosphor. 6. The method for producing a radiation image storage panel according to claim 5, wherein the radiation image storage panel contains a small coloring agent.