JP2003240899A - Radiation image conversion panel and method for manufacturing it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation image conversion panel with a superior brightness stability that prevents the yellowing due to heat or moisture absorption during manufacturing stage and long conservation. <P>SOLUTION: The radiation image conversion panel having a stimulable phosphor layer containing stimulable phosphor and a bonding agent on a support body is characterized in that the stimulable phosphor layer contains iodine and the isocyanate concentration contained at the depth of 180 μm from the surface is 0-70 ppm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation image conversion panel and a method of manufacturing the same, and more particularly to a radiation image conversion panel having improved yellowing and brightness stability during storage.

[0002]

2. Description of the Related Art Radiation images such as X-ray images are widely used in the fields of disease diagnosis and the like. This X-ray image can be obtained by irradiating the phosphor layer (fluorescent screen) with X-rays that have passed through the subject to generate visible light, which is the same as when taking a normal photo. Then, a so-called radiographic method is widely used in which a silver halide photographic light-sensitive material (hereinafter, also simply referred to as a light-sensitive material) is irradiated and then developed to obtain a visible silver image.

However, in recent years, as an effective diagnostic means replacing such conventional radiography, Japanese Patent Application Laid-Open No. Sho 5 has been proposed.
A radiation image recording / reproducing method using a stimulable phosphor described in JP-A No. 5-12145 is known. This method uses a radiation image conversion panel containing a stimulable phosphor (also called a stimulable phosphor sheet), and the radiation transmitted through an object or emitted from a subject is stimulable phosphor. Is absorbed into the stimulant, and the stimulable phosphor is excited in time series with electromagnetic waves such as visible light and ultraviolet rays (called excitation light), and the accumulated radiation energy is fluoresced (called stimulated emission light).
The fluorescence signal is photoelectrically read to obtain an electric signal, and the radiation image of the subject or the subject is reproduced as a visible image based on the obtained electric signal. After the reading, the conversion panel erases the remaining image and is used for the next photographing.

According to this method, compared with the radiographic method using a combination of a radiographic film and an intensifying screen,
There is an advantage that a radiation image with abundant information can be obtained with a much smaller exposure dose. Further, in the radiographic method, the film is consumed for each photographing, whereas the radiation image conversion panel is repeatedly used, which is advantageous in terms of resource protection and economic efficiency.

The radiation image conversion panel comprises a support and a stimulable phosphor layer provided on the surface thereof, or a self-supporting stimulable phosphor layer. The stimulable phosphor layer is usually composed of Some include a stimulable phosphor and a binder that disperses and supports it, and others include only an aggregate of the stimulable phosphor formed by a vapor deposition method or a sintering method. Also known is one in which the gap between the aggregates is impregnated with a polymer substance. Further, on the surface of the stimulable phosphor layer opposite to the support side, a protective film composed of a polymer film or a vapor deposition film of an inorganic material is usually provided.

The above-described stimulable phosphor is a phosphor that exhibits stimulated emission when irradiated with excitation light after being irradiated with radiation, but in practice, excitation light having a wavelength in the range of 400 to 900 nm is used. Therefore, a phosphor that exhibits stimulated emission in the wavelength range of 300 to 500 nm is generally used.

A radiation image conversion panel using these stimulable phosphors releases radiation energy by scanning excitation light after storing radiation image information. Therefore, radiation images can be stored again after scanning. Although it can be repeatedly used, it is desirable that the radiation image conversion panel used in such a manner be provided with a performance that can be used for a long period of time without deteriorating the image quality of the obtained radiation image. However, when a stimulable phosphor used for manufacturing a radiation image conversion panel, particularly a stimulable phosphor containing iodine is used, iodine is liberated from the phosphor to form an iodine molecule (I ₂ ). Therefore, the phosphor layer has a characteristic that it tends to gradually turn yellow. As described above, the radiation image conversion panel having the yellow phosphor layer has a problem that the sensitivity is significantly lowered.

The liberation of iodine and the formation of I ₂ gradually occur with long-term storage, but it is considered to be promoted by moisture absorption and heating of the phosphor, and accordingly, the stimulable phosphor is further enhanced. This results in yellowing, which results in a decrease in brightness and other deterioration in basic performance depending on the characteristics of the stimulable phosphor particles. The above-mentioned yellowing phenomenon is a problem caused by moisture absorption, heating, etc. even in the initial stage of production in addition to the above-mentioned conditions, and a technical means for preventing yellowing of stimulable phosphor particles was needed. .

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to prevent yellowing due to heat and moisture absorption in the manufacturing stage and long-term storage, and to have excellent brightness stability. A radiation image conversion panel and a method for manufacturing the same.

[0010]

The above objects of the present invention have been achieved by the following constitutions.

1. In a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, the stimulable phosphor layer contains iodine and has a depth of 180 μm from the surface portion. The radiation image conversion panel is characterized in that the concentration of the isocyanate group contained in the region is 0 to 70 ppm.

2. In a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, the stimulable phosphor contains iodine, and the binder has an isocyanate group content rate. A radiation image conversion panel, wherein the radiation image conversion panel is a polymer resin having a content of 0 to 1000 ppm.

3. 3. The radiation image conversion panel according to the above item 2, wherein the polymer resin has a urethane bond in the main chain.

4. The stimulable phosphor is Eu-added BaFB
The radiation image conversion panel according to any one of items 1 to 3, wherein r _X I _(1-X) (0 ≦ X <1).

5. In a method for producing a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, the stimulable phosphor contains iodine, and an isocyanate is used as the binder. Group content is 0-10
A method for producing a radiation image conversion panel, which is produced using a polymer resin having a concentration of 00 ppm.

6. 6. The method for manufacturing a radiation image conversion panel according to the above item 5, wherein the polymer resin has a urethane bond in the main chain.

7. The stimulable phosphor is Eu-added BaFB
r _X I _(1-X) (0 ≦ X <1), The method for producing a radiation image conversion panel according to the above item 5 or 6, wherein

The present inventor has found that when a stimulable phosphor containing iodine (hereinafter, also simply referred to as a phosphor) is used in a radiation image conversion panel, the stimulable phosphor layer (hereinafter, also simply referred to as a phosphor layer). Yellowish), and as a result, the stimulated emission light emitted from the phosphor is absorbed in the phosphor layer, resulting in a significant decrease in brightness. This occurs when the image conversion panel is manufactured and stored for a long period of time in a high humidity environment. This is because iodine is liberated as I ₂ molecules from the phosphor in the phosphor layer coating solution, or It is believed to be due to the formation of I ₂ molecules in the layer.

As a result of earnestly analyzing the above problems, the present inventors have found that one of the factors accelerating the yellowing is that the isocyanate group contained in the radiation image conversion panel has a great influence. I found it. Examples of the compound containing an isocyanate group used in the radiation image conversion panel include, for example, an undercoat layer mainly provided for the purpose of improving the adhesiveness between the support and the phosphor layer, which is mainly used as a crosslinking agent for the binder. A functional isocyanate compound is used, and as a binder for the phosphor layer, a polyurethane-based resin is widely used from the viewpoint that it has a strong binding force with the phosphor, excellent dispersibility, and excellent ductility. ,
A polyisocyanate compound is generally used in the synthesis of the polyurethane resin, and an isocyanate group is contained in the final radiation image conversion panel.

In the present invention, by defining the content of the isocyanate group and the area where the isocyanate group is distributed, the yellowing during storage and the accompanying decrease in brightness are prevented, that is, in the radiation image conversion panel, the fluorescence is reduced. By adjusting the concentration of the isocyanate group contained in a region of a depth of 180 μm from the surface of the body layer to 0 to 70 ppm and using a polymer resin having an isocyanate group content of 0 to 1000 ppm as a binder, It has been found that the present invention can be prevented, and that the present invention can prevent a decrease in luminance accompanying the change.

The details of the present invention will be described below. In the invention according to claim 1, in a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, the stimulable phosphor layer contains iodine. ,
The concentration of the isocyanate group contained in the region 180 μm deep from the surface is 0 to 70 ppm, and the concentration of the isocyanate group is preferably 0 pp.
m. By setting the conditions defined above, by reducing the influence of the isocyanate group in the phosphor layer surface region, which particularly contributes significantly to the brightness, the influence on the phosphor particles containing iodine during high humidity storage It can be reduced.

In the present invention, the method for measuring the concentration of the isocyanate group in the phosphor layer is not particularly limited, but, for example, from the surface of the phosphor layer coated on the support,
Using an ultramicrotome, trimming is performed sequentially as a thin layer of 5 to 10 μm, and the depth from the surface is 177.5 to
A 5 μm-thick piece corresponding to a region of 182.5 μm is taken out, the content of the isocyanate group per unit mass is quantified by a known quantification method, and its distribution can be obtained.

As a method for achieving the distribution of isocyanate groups in the phosphor layer specified in the present invention, an undercoat layer is provided between the phosphor layer and the support, and the isocyanate group-containing compound is used as a crosslinking agent in the undercoat layer. When using, after applying an undercoat layer, or after applying a phosphor layer, heat treatment is performed to completely crosslink the remaining unreacted isocyanate groups, and during storage There is a method of preventing the unreacted isocyanate group from diffusing into the phosphor layer, or a method of increasing the film thickness of the phosphor layer to particularly reduce the influence of the isocyanate group on the surface layer portion of the phosphor layer.

In the phosphor layer, it is extremely effective means to use a polymer resin having an isocyanate group content of 0 to 1000 ppm as a binder.
Further, as the polymer resin, it is preferable to use a compound having a urethane bond in the main chain. By reducing the influence of the isocyanate group under the conditions specified in the present invention, it is possible to reduce the influence on the phosphor particles containing iodine during high humidity storage.

In the present invention, the isocyanate group content is 0.
A polymer resin having a concentration of up to 1000 ppm is a polymer resin in which, even if an isocyanate group is used in the synthesis of the polymer resin, isocyanate groups do not exist at both ends of the polymer molecule or the ratio thereof is extremely low. Means

Further, polymer resins having a urethane bond in the main chain are generally referred to as urethane resins, and polyisocyanates and active compounds such as polyols utilizing the reactivity of the isocyanate groups with active hydrogen compounds in the resin structure. Urethane bond obtained by polyaddition reaction with
By a bond resulting from the reaction of an isocyanate group with an active hydrogen such as a urea (urea) bond, a burette / allophanate bond, an ester bond, an ether bond, an amide bond, and a reaction between isocyanate groups contained in the molecule of an active hydrogen compound. Produces uretdione, isocyanurate,
It is a polymer compound that also contains carbodiimide and the like. Generally, a polyurethane resin has an intermolecular 2 due to a urethane bond or a urea bond having a large cohesive energy existing in the molecule.
Due to the secondary bond, it has excellent mechanical properties, abrasion resistance, durability, and chemical resistance. Further, the performance can be greatly changed by controlling the type of raw materials used such as polyisocyanate and active hydrogen compound, the composition ratio reaction conditions and the like.

Examples of the polyisocyanate used for synthesizing the polyurethane resin of the present invention include, but are not limited to, the following. Toluene diisocyanate, diphenylmethane diisocyanate, 1,6-hexamethylene diisocyanate, 2,
2,4 (2,4,4) -trimethylhexamethylene diisocyanate, p-phenylene diisocyanate, 4,
4'-dicyclohexylmethane diisocyanate, 3,
3'-dimethyldiphenyl-4,4'-diisocyanate, dianisidine diisocyanate, m-xylene diisocyanate, 1,3-bis (isocyanatomethyl)
Cyclohexane, tetramethyl xylene diisocyanate, isophorone diisocyanate, 1,5-naphthalene diisocyanate, 1,4-cyclohexyl diisocyanate, lysine diisocyanate, dimethyltriphenylmethane tetraisocyanate, triphenylmethane triisocyanate, tris (isocyanatophenyl) thiophosphate, urethane Modified toluene diisocyanate, allophanate modified toluene diisocyanate,
Biuret modified toluene diisocyanate, isocyanurate modified toluene diisocyanate, urethane modified diphenylmethane diisocyanate, carbodiimide modified diphenylmethane diisocyanate, uretonimine modified diphenylmethane diisocyanate, acylurea modified diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate and the like.

These isocyanate compounds may be used alone, or in advance, reaction products of a plurality of types of polyisocyanates, reaction products of ethylene oxide adducts of methanol or ethanol with polyisocyanates,
Further, it may be used as a compound having a free isocyanate group obtained by reacting a compound having two or more active hydrogens in one molecule with a polyisocyanate.

A specific method for synthesizing a polyurethane resin is described in JP-A-5-127306, JP-A-6-67328, and JP-A-6-67328.
293821, JP-A-4-96919, JP-A-58
-63716, 58-80320, 63-30
1251, 56-151753, JP-A-2-26
9723, 7-10950 and the like. In addition, the detailed polyurethane synthesis method is also described in "Polyurethane Handbook" (1985) by Gunter Otel, "Polyurethane Foam" (1987) by Yoshio Imai, "Water-Based Paint and Coating Technology" (1992) published by Technical Information Association.

Examples of commercially available polyurethane resins include Superflex series 107, 110, 126, 150, 160, 1 manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
90, 300, 361, 410, 460, 750, 82
0, Superflex E series E-2000, E
-2500, E-4500. Takeraku W Co., Ltd. Takerak W Series W-6015, W-621, W-5
11, XW-75-P15, W-512A, W-63
5, W-7004, XW-97-W6, AW-605,
Examples include ACW-54HD, silanol group-containing Takelac XW series, Dainippon Ink and Chemicals Co., Ltd. Pandex series, Nippon Polyurethane Co., Ltd. Nippon Polan series, and the like. As the heat-reactive water-based polyurethane resin, there are Elastron series manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Takenate WB series WB-700, WB-710, WB-720 manufactured by Takeda Pharmaceutical Co., Ltd.
Examples thereof include WB-730 and WB-920. From the viewpoint of a polymer resin having an isocyanate group content of 0 to 1000 ppm defined in claim 2, Nippon Polyurethane Industry Co., Ltd.'s Nipporan 230 is particularly preferable.
4 is particularly preferred.

Next, each component of the radiation image conversion panel of the present invention will be described. The radiation image conversion panel of the present invention mainly comprises a support and a phosphor layer, and if necessary, an undercoat layer is provided between the support and the phosphor layer. The phosphor layer is generally composed of a phosphor and a polymer resin that holds the phosphor in a dispersed state. In addition, a protective layer film made of a polymer film or a vapor deposition film of an inorganic material is usually provided on the surface of the phosphor layer opposite to the support side.

As the support or temporary support which can be used in the present invention, for example, those made of various materials such as glass, wool, cotton, paper and metal can be used. Information recording In terms of handling as a material, a material that can be processed into a flexible sheet or roll is preferable. From this point, for example, cellulose acetate film, polyester film, polyethylene terephthalate film, polyamide film, polyimide film, triacetate film, plastic film such as polycarbonate film, aluminum foil, metal sheet such as aluminum alloy foil, general paper and for photography Base paper, coated paper, or base paper for printing such as art paper, baryta paper, resin coated paper, paper sized with polysaccharides as described in Belgian Patent No. 784,615, titanium dioxide, etc. Pigment paper containing the above pigment, and processed paper such as paper sized with polyvinyl alcohol are particularly preferable. The film thickness of these supports varies depending on the material of the support used and the like, but is generally 80 to 1000 μm, and more preferably 80 to 500 μm from the viewpoint of handling. The surface of these supports may be a smooth surface, or may be a matte surface for the purpose of improving the adhesion with the undercoat layer described later.

Next, the undercoat layer will be described. The undercoat layer according to the present invention mainly contains a polymer resin that can be crosslinked with a crosslinking agent and a crosslinking agent.

The polymer resin that can be used in the undercoat layer is not particularly limited, but for example, polyurethane,
Polyester, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative ( Nitrocellulose etc.), styrene-butadiene copolymers, various synthetic rubber resins, phenol resins, epoxy resins, urea resins,
Examples thereof include melamine resin, phenoxy resin, silicone resin, acrylic resin, urea formamide resin and the like. Among them, polyurethane, polyester, vinyl chloride copolymer, polyvinyl butyral, nitrocellulose and the like can be mentioned, and the average glass transition temperature (Tg) of the polymer resin used in the undercoat layer is 25 ° C. or higher. Is preferable, and more preferably, a polymer resin having a Tg of 25 to 200 ° C. is used.

The crosslinking agent that can be used in the undercoat layer according to the present invention is not particularly limited, and examples thereof include polyfunctional isocyanates and their derivatives, melamine and its derivatives, amino resins and their derivatives, and the like. However, in the present invention, it is preferable to use a polyfunctional isocyanate compound as a crosslinking agent, and examples thereof include Coronate HX and Coronate 3041 manufactured by Nippon Polyurethane Company.

The undercoat layer according to the present invention can be formed on a support by the following method, for example.

First, the above-mentioned polymer resin and cross-linking agent are added to a suitable solvent, for example, the solvent used in the preparation of the coating solution for the stimulable fluorescent layer described below, and the resulting mixture is mixed sufficiently to prepare an undercoat layer coating solution. To prepare.

The amount of the crosslinking agent used varies depending on the characteristics of the intended radiation image conversion panel, the type of material used for the stimulable phosphor layer and the support, the type of polymer resin used for the undercoat layer, etc. Considering the maintenance of the adhesive strength of the stimulable phosphor layer to the support, 50% by mass relative to the polymer resin
It is preferable to add it at the following ratio, particularly preferably 15 to 50% by mass.

The thickness of the undercoat layer is the desired characteristics of the radiation image conversion panel, the type of material used for the stimulable phosphor layer and the support, the type of polymer resin and crosslinker used for the undercoat layer, etc. Generally, the thickness is preferably 3 to 50 μm, and particularly preferably 5 to 40 μm. The undercoat layer may be colored if necessary.

In the present invention, the reaction between the polymer resin contained in the undercoat layer and the cross-linking agent is performed after coating the above-mentioned undercoat layer on the support and before coating the stimulable phosphor layer. In order to complete the heat treatment, it is preferable to perform heat treatment at 40 to 150 ° C. for 2 to 100 hours. Performing this heat treatment before coating the phosphor layer is one of the preferable means for realizing the distribution state of the isocyanate groups in the phosphor layer defined in the present invention.

The heat treatment method is not particularly limited, and any method can be used as long as the prepared sheet-shaped or roll-shaped sample with the undercoat layer coated thereon can be completely stored and the temperature and humidity can be controlled. May be used. In the invention according to claim 1, the heat treatment conditions are 2 to 10 at 40 to 150 ° C.
Characteristically, it is 0 hour, but preferably 55 to 1
00 ° C., 5 to 50 hours.

Next, the stimulable phosphor layer will be described. The stimulable phosphor layer according to the present invention contains at least a stimulable phosphor and a polymer resin.

As the stimulable phosphor that can be used in the present invention, those having an emission wavelength in the wavelength range of 400 to 900 nm are generally used.

Hereinafter, examples of phosphors that can be used in the radiation image conversion panel of the present invention will be given.

(1) (Ba _1-X , M (II) _X ) FX: yA described in JP-A-55-12145 (wherein
M (II) is at least one of Mg, Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, P
At least one of r, Ho, Nd, Yb, and Er, and 0 ≦ x ≦ 0.6, y is 0 ≦ y ≦ 0.
2) The rare earth element-activated alkaline earth metal fluorohalide phosphor represented by the composition formula; The phosphor may further contain the following additives.

A) X ', BeX ", M (III) X"' ₃ , described in JP-A-56-74175, wherein:
X ', X ", and X"' are at least one of Cl, Br, and I, respectively, and M (III) is a trivalent metal. B) Be described in JP-A-55-160078.
O, MgO, CaO, SrO, BaO, ZnO, Al ₂
O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , Ti
O ₂ , ZrO ₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅
And metal oxides such as ThO ₂ c) Z described in JP-A-56-116777
r, Sc d) Be described in JP-A-57-23673, As) described in JP-A-57-23675,
Sif) M. described in JP-A-58-206678
L, in the formula, M is at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs, and L is Sc, Y, La, Ce, Pr, Nd, Pm, S.
m, Gd, Tb, Dy, Ho, Er, Tm, Yb, L
g) at least one trivalent metal selected from the group consisting of u, Al, Ga, In, and Tl) A fired product of a tetrafluoroboric acid compound described in JP-A-59-27980; 59-2728
Calcinated products of monovalent or divalent metal salts of hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid described in JP-A-9-56;
NaX 'described in Japanese Patent No. 479, wherein X'is C
at least one of l, Br and I h) V and C described in JP-A-59-56480
Transition metals such as r, Mn, Fe, Co and Ni; M (I) X 'described in JP-A-59-75200.
M ′ (II) X ″ ₂ , M (III) X ″ ″ ₃ , A, in the formula, M
(I) is at least one alkali metal selected from the group consisting of Li, Na, K, Rb, and Cs,
M '(II) represents at least one divalent metal selected from the group consisting of Be and Mg, and M (III) represents Al, G
at least one trivalent metal selected from the group consisting of a, In, and Tl, A is a metal oxide,
X ′, X ″, and X ″ ″ are F, Cl, Br, respectively.
And at least one halogen selected from the group consisting of I and i) M described in JP-A-60-101173.
(I) X ′, wherein M (I) is at least one alkali metal selected from the group consisting of Rb and Cs,
X'is at least one halogen selected from the group consisting of F, Cl, Br and I. j) M (I) described in JP-A No. 61-23679.
I) ′ X ′ ₂ · M (II) ′ X ″ ₂ , where M (II) ′ is B
at least one alkaline earth metal selected from the group consisting of a, Sr and Ca; X ′ and X ″ are at least one halogen selected from the group consisting of Cl, Br and I, and X ′. ≠ X ″;
Further, LnX ″ ₃ described in JP-A-61-264084, in which Ln is Sc, Y, La, Ce,
Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, E
at least one rare earth element selected from the group consisting of r, Tm, Yb and Lu; X ″ is F, Cl, Br
And at least one halogen selected from the group consisting of I and I.

(2) M (II) X ₂ · aM (II) X ′ ₂ : xEu ^{2+ described in} JP-A-60-84381 (wherein M (II) is Ba, Sr and Ca) Is at least one alkaline earth metal selected from the group consisting of; X and X'are at least one halogen selected from the group consisting of Cl, Br and I, and X ≠ X '; and a Is 0.1 ≦ a ≦ 10.0, x is 0 <x ≦
0.2) The divalent europium-activated alkaline earth metal halide phosphor represented by the composition formula; and the phosphor may contain the following additives.

A) M (I) X 'described in JP-A-60-166379, wherein M (I) is Rb and C.
at least one alkali metal selected from the group consisting of s; X'is at least one halogen selected from the group consisting of F, Cl, Br and I. b) Described in JP-A-60-221483. K
X ″, MgX ″ ″ ″ ₂ , M (III) X ″ ″ ₃ , where M (I
II) is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu; X ″,
X ″ ″ and X ″ ″ are both at least one halogen selected from the group consisting of F, Cl, Br and I. c) B described in JP-A-60-228592,
Si described in JP-A-60-228593
O _2, P ₂ O ₅ oxide such, LiX listed in JP 61-120882 ", NaX", in the formulas, X "at least selected from the group consisting of F, Cl, Br and I D) a kind of halogen Si described in JP-A-61-120883
O: Sn described in JP-A-61-120885
X ″ ₂ , where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I. e) Cs described in JP-A-61-235486
X ″, SnX ″ ″ ₂ , where X ″ and X ″ ″ are each at least one halogen selected from the group consisting of F, Cl, Br and I;
No. 235487, CsX ″, Ln ³⁺ , where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I; Ln is Sc,
Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, H
(3) Ln described in JP-A-55-12144, which is at least one rare earth element selected from the group consisting of o, Er, Tm, Yb and Lu.
OX: xA (where Ln is La, Y, Gd, and Lu
X is at least one of Cl, Br, and I; A is at least one of Ce and Tb; x is 0 <x <0.1). Rare earth element activated rare earth oxyhalide phosphor.

(4) M (II) OX: xCe described in JP-A-58-69281 (wherein M (II) is P
r, Nd, Pm, Sm, Eu, Tb, Dy, Ho, E
at least one metal oxide selected from the group consisting of r, Tm, Yb, and Bi; X is at least one of Cl, Br, and I; x is 0 <x <0.1
Is a cerium-activated trivalent metal oxyhalide phosphor.

(5) M (I) X: xBi described in JP-A-62-25189 (wherein M (I) is at least one alkali metal selected from the group consisting of Rb and Cs). X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a numerical value in the range of 0 <x ≦ 0.2). Metal halide phosphor.

(6) M (II) ₅ (PO ₄ ) ₃ X: xEu ²⁺ described in JP-A-60-141783 (wherein
M (II) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is F,
A divalent europium-activated alkaline earth metal haloline represented by the composition formula: at least one halogen selected from the group consisting of Cl, Br and I; x is a numerical value in the range of 0 <x ≦ 0.2. Phosphate phosphor.

(7) M (II) ₂ BO ₃ X: xEu ²⁺ (in the formula, M (I
I) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is Cl, B
a divalent europium-activated alkaline earth metal haloborate represented by the composition formula: at least one halogen selected from the group consisting of r and I; x is a numerical value in the range of 0 <x ≦ 0.2. Phosphor.

(8) M (II) ₂ (PO ₄ ) ₃ X: xEu ²⁺ described in JP-A-60-157100 (wherein
M (II) is at least one alkaline earth metal selected from the group consisting of Ca, Sr and Ba; X is C
a divalent europium-activated alkaline earth metal haloline represented by the composition formula: at least one halogen selected from the group consisting of 1, Br and I; x is a numerical value in the range of 0 <x ≦ 0.2. Phosphate phosphor.

(9) M (II) HX: xEu ²⁺ described in JP-A-60-217354 (wherein M (II) is at least one selected from the group consisting of Ca, Sr and Ba) Alkaline earth metal; X is at least one halogen selected from the group consisting of Cl, Br and I; x is a numerical value in the range of 0 <x ≦ 0.2) Divalent europium activated alkaline earth metal hydrohalide phosphor.

(10) LnX ₃ .aLn'X ' ₃ : xCe ³⁺ described in JP-A-61-211173 (wherein Ln and Ln' are each of Y, La, Gd and Lu). At least one rare earth element selected from the group; X and X'each being at least one halogen selected from the group consisting of F, Cl, Br and I, and X ≠ X '; and a is 0.1 <a
A numerical value in the range of ≦ 10.0, and x is a numerical value in the range of 0 <x ≦ 0.2).

[0056] (11) LnX ₃ · aM that are described in ^{JP-A-61-21182 (I) X'3: xCe 3+} ,
(In the formula, Ln is at least one rare earth element selected from the group consisting of Y, La, Gd, and Lu; M
(I) is at least one alkali metal selected from the group consisting of Li, Na, K, Cs and Rb; X and X ′ are at least one halogen selected from the group consisting of Cl, Br and I, respectively. And a is a numerical value in the range of 0 <a ≦ 10.0, and x is 0 <x ≦
A cerium-activated rare-earth composite halide-based phosphor represented by a composition formula of 0.2).

(12) LnPO ₄ .aLnX ₃ : xCe ³⁺ , described in JP-A-6140390, (in the formula,
Ln is at least one rare earth element selected from the group consisting of Y, La, Gd and Lu; X is F, Cl,
At least one halogen selected from the group consisting of Br and I; and a is a numerical value in the range of 0.1 ≦ a ≦ 10.0 and x is a numerical value in the range of 0 <x ≦ 0.2. ) A cerium-activated rare earth halophosphate phosphor represented by the composition formula (1).

(13) CsX: aRbX ': xEu ²⁺ described in JP-A-61-2336888,
(Wherein X and X ′ are at least one halogen selected from the group consisting of Cl, Br and I respectively; and a is a numerical value in the range of 0 <a ≦ 10.0,
x is a numerical value in the range of 0 <x ≦ 0.2), which is a divalent europium-activated cesium rubidium halide phosphor represented by the composition formula.

(14) M (II) X ₂ · aM (I) X ′: xE described in JP-A-61-2336890.
u ²⁺ , where M (II) is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; M (I) is selected from the group consisting of Li, Rb and Cs At least one alkali metal; X and X ′ are each at least one halogen selected from the group consisting of Cl, Br and I; and a is a numerical value in the range of 0.1 ≦ a ≦ 20.0. , X is 0 <x
A divalent europium-activated composite halide phosphor represented by the composition formula: ≦ 0.2).

Among the above stimulable phosphors, a divalent europium-activated alkaline earth metal fluoride halide-based phosphor containing iodine and a divalent europium-activated alkaline earth metal halide-based phosphor containing iodine. The rare earth element-activated rare earth oxyhalide-based phosphor containing iodine, and a bismuth-activated alkali metal halide-based phosphor containing iodine are preferable because they exhibit stimulated luminescence with high brightness, and the invention according to claim 4 In, the stimulable phosphor is preferably Eu-added BaFBr _X I _(1-X) (0 ≦ X <1).

The photostimulable phosphor according to the present invention is preferably contained in the photostimulable phosphor layer in a form dispersed in a polymer resin. As the polymer resin that can be used in the present invention, the conditions specified in the present invention, that is, the concentration of the isocyanate group contained in the region of a depth of 180 μm from the surface of the phosphor layer is 0 to 70 ppm, the isocyanate group is In addition to the urethane resin having a low addition number of the isocyanate group at the above-mentioned terminal, a known polymer resin may be used in combination as long as the condition for the polymer resin having a content of 0 to 1000 ppm is satisfied. For example, polyester, vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer,
Vinyl chloride-acrylonitrile copolymer, butadiene-
Acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (nitrocellulose etc.), styrene-butadiene copolymer, various synthetic rubber resins, phenol resin, epoxy resin, urea resin, melamine resin, phenoxy resin, silicone resin , Acrylic resin, urea formamide resin and the like. Among them, polyester, vinyl chloride copolymer, polyvinyl butyral, nitrocellulose and the like can be mentioned.

The coating liquid for the stimulable phosphor layer used in the present invention is
The polymer resin and the stimulable phosphor particles are added to an appropriate organic solvent, and, for example, using a disperser or a ball mill, the mixture is stirred and mixed so that the stimulable phosphor is contained in the polymer resin. Prepare so that it is evenly dispersed. Examples of the solvent used for preparing the stimulable phosphor layer coating solution include lower alcohols such as methanol, ethanol, n-propanol and n-butanol, chlorine atom-containing hydrocarbons such as methylene chloride and ethylene chloride, acetone, and the like. Ketones such as methyl ethyl ketone and methyl isobutyl ketone, aromatic compounds such as toluene, benzene, cyclohexane, cyclohexanone and xylene, esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate and butyl acetate, dioxane, ethylene glycol monoethyl ester , Ethers such as ethylene glycol monomethyl ester and mixtures thereof.

The stimulable phosphor coating liquid may contain, if necessary, a dispersant for improving the dispersibility of the stimulable phosphor in the coating liquid or a stimulable phosphor after panel formation. Various additives such as a plasticizer for improving the binding force between the polymer resin and the stimulable phosphor in the layer may be mixed.

Examples of dispersants include phthalic acid, stearic acid, caproic acid, lipophilic surfactants and the like. Examples of the plasticizer include triphenyl phosphate, tricresyl phosphate, diphenyl phosphate, and other phosphoric acid esters, diethyl phthalate, dimethoxyethyl phthalate, and other phthalic acid esters, ethyl phthalyl glycolate, butyl phthalyl glycolate, and the like. Examples of the glycolic acid ester include polyesters of triethylene glycol and adipic acid, polyesters of polyethylene glycol and aliphatic dibasic acids such as polyesters of diethylene glycol and succinic acid, and the like.

The coating solution for the stimulable phosphor layer is usually prepared by
It is carried out using a dispersing device such as a ball mill, a sand mill, an attritor, a three-roll mill, a high speed impeller disperser, a Kady mill, and an ultrasonic disperser. The prepared coating liquid is, for example, using a known coating coater such as a doctor blade, a roll coater, a knife coater, and an extrusion coater, after coating on a support, followed by drying, to form an undercoat layer. The formation of the stimulable phosphor layer is completed.

The film thickness of the stimulable phosphor layer of the radiation image conversion panel of the present invention depends on the desired characteristics of the radiation image conversion panel, the type of stimulable phosphor, the polymer resin and the stimulable phosphor. Although it depends on the mixing ratio and the like, it is preferably selected from the range of 10 to 1000 μm, more preferably 10 to 500 μm.

The phosphor sheet having the stimulable phosphor layer coated on the support is cut into a predetermined size. Although any general method can be used for cutting, a cosmetic cutting machine, a punching machine or the like is preferable in terms of workability and accuracy.

The radiation image conversion panel of the present invention is preferably provided with a protective film (also referred to as a protective film) for physically and chemically protecting the surface of the stimulable phosphor layer. It can be appropriately selected depending on the purpose, use and the like.

As the protective layer provided on the radiation image conversion panel of the present invention, a polyester film or a polymethacrylate having an excitation light absorbing layer having a haze ratio of 5% or more and less than 60% as measured by the method described in ASTM D-1003. A film, a nitrocellulose film, a cellulose acetate film or the like can be used, but a stretched film such as a polyethylene terephthalate film or a polyethylene naphthalate film is preferable as the protective layer in terms of transparency and strength, and further, these From the viewpoint of moisture resistance, a polyethylene terephthalate film or a vapor-deposited film obtained by vapor-depositing a thin film of a metal oxide, silicon nitride or the like on a polyethylene terephthalate film is more preferable.

The haze ratio of the film used in the protective layer can be easily adjusted by selecting the haze ratio of the resin film to be used, and a resin film having an arbitrary haze ratio can be easily obtained industrially. . As a protective film for a radiation image conversion panel, one having a very high optical transparency is supposed. As such a highly transparent protective film material, various plastic films having a haze value in the range of 2 to 3% are commercially available. The preferred haze ratio for obtaining the effect of the present invention is 5%.
Or more and less than 60%, more preferably 10% or more 5
It is less than 0%. If the haze ratio is less than 5%, the effect of eliminating image unevenness and linear noise is low, and if it is 60% or more, the effect of improving sharpness is impaired, which is not preferable.

In the present invention, the film used as the protective layer has an optimum moisture-proof property by laminating a plurality of resin films or vapor-deposited films obtained by vapor-depositing a metal oxide on the resin film, in accordance with the required moisture-proof property. Can be
The moisture permeability is preferably at least 50 g / m ² · day or less in consideration of prevention of moisture deterioration of the stimulable phosphor. The method for laminating the resin film is not particularly limited, and any known method may be used.

Further, by providing the excitation light absorption layer between the laminated resin films, the excitation light absorption layer is protected from physical impact and chemical alteration, and stable plate performance can be maintained for a long time, which is preferable. Further, the excitation light absorption layer may be provided at a plurality of positions, or the adhesive layer for laminating may contain a coloring agent to form the excitation light absorption layer.

The protective film may be adhered to the stimulable phosphor layer through an adhesive layer, but the structure is provided so as to cover the phosphor surface (hereinafter, also referred to as sealing or sealing structure). Is more preferable. In sealing the phosphor plate, any known method may be used, but the outermost resin layer on the side in contact with the phosphor sheet of the moisture-proof protective film is a resin film having heat-sealing property, and it is moisture-proof. This is one of the preferable modes in that the property protection film can be fused and the work of sealing the phosphor sheet can be made efficient.
Furthermore, the moisture-proof protective film is arranged on the upper and lower sides of the phosphor sheet, and the peripheral edge thereof is an area outside the peripheral edge of the phosphor sheet. The sealing structure is preferable because moisture can be prevented from entering from the outer peripheral portion of the phosphor sheet.
Further, the moisture-proof protective film on the support surface side is 1
By using a laminated moisture-proof film obtained by laminating aluminum films having more layers, it is possible to more reliably reduce the ingress of moisture, and this sealing method is also easy in terms of work, which is preferable. In the method of heat fusion with the impulse sealer, heat fusion in a reduced pressure environment is more preferable in terms of preventing displacement of the phosphor sheet in the moisture-proof protective film and eliminating moisture in the atmosphere.

The resin layer, which is the outermost layer having the heat-sealing property, on the side of the moisture-proof protective film that comes into contact with the phosphor surface and the phosphor surface may or may not be adhered. The term "non-adhesive" as used herein means that, even if the phosphor surface is microscopically in point contact with the moisture-proof protective film, the phosphor surface and the moisture-proof protective film are almost discontinuous optically and mechanically. It is a state that can be treated as a body. Further, the above-mentioned resin film having heat-fusible property is a resin film that can be fused by a commonly used impulse sealer, and is, for example, ethylene vinyl acetate copolymer (EVA) or polypropylene (P
P) film, polyethylene (PE) film and the like can be mentioned, but the present invention is not limited thereto.

[0075]

[Examples] Hereinafter, specific examples will be described.
The invention is not limited to these examples.

Example 1 Preparation of Radiation Image Conversion Panel (Preparation of Photostimulable Phosphor) In order to synthesize a photostimulable phosphor precursor of europium-activated barium fluoroiodide, BaI was prepared.
2780 ml of ₂ aqueous solution (3.6 mol / L) and 27 ml of EuI ₃ aqueous solution (0.15 mol / L) were placed in the reactor. The reaction mother liquor in this reactor was kept warm at 83 ° C. with stirring. Then, an ammonium fluoride aqueous solution (8 mol /
L) 322 ml was injected into the reaction mother liquor using a roller pump to form a precipitate. After completion of the injection, the heat retention and stirring were continued for 2 hours to ripen the precipitate. Next, the precipitate was separated by filtration, washed with ethanol, and then dried in vacuum to obtain europium-activated barium fluoroiodide crystals.
In order to prevent changes in particle shape due to sintering during firing, and changes in particle size distribution due to fusion between particles, 0.2% by mass of ultrafine alumina powder was added, and the surface of the crystal was thoroughly stirred with a mixer. Ultra fine particles of alumina were uniformly adhered to the surface. This was filled in a quartz boat and fired at 850 ° C. for 2 hours in a hydrogen gas atmosphere using a tube furnace to obtain europium-activated barium fluoroiodide phosphor particles. Next, the above phosphor particles were classified to prepare a phosphor having an average particle diameter of 4 μm.

(Preparation of Phosphor Layer Coating Solution 1) 480 g of the europium-activated barium fluoroiodide phosphor prepared above
And 20.0 g of polyester resin having Tg of 30 ° C. are added to a 1: 1 mixed solvent of methyl ethyl ketone: toluene and dispersed by a propeller mixer to give a viscosity of 25 to 3
A 0 mPa · s phosphor layer coating solution 1 was prepared.

(Preparation of Coating Liquid for Undercoat Layer) 100 parts by mass of the polyester resin and 10 parts by mass of Coronate HX (manufactured by Nippon Polyurethane Co., Ltd.), which is a polyfunctional isocyanate compound as a cross-linking agent, were mixed, and this mixture was mixed with methyl ethyl ketone: It was added to a 1: 1 mixed solvent of toluene and dispersed by a propeller mixer to prepare an undercoat layer coating solution having a viscosity of 500 mPa · s.

(Preparation of Phosphor Sheets 1A, 1B, 1C) <Coating of Undercoat Layer> On the 250 μm thick carbon-kneaded black polyethylene terephthalate support, the above-prepared undercoat layer coating solution was prepared. After coating using a knife coater so that the dry film thickness would be 15 μm, it was dried to prepare an undercoat layer-coated sample.

<Heat Treatment of Undercoat Layer-Coated Sample> A part of the above-prepared undercoat layer-coated sample was subjected to the following heat treatment 1 or heat treatment 2.

Heat treatment 1: Heat treatment was performed at 60 ° C. for 3 hours. Heat treatment 2: Heat treatment was performed at 60 ° C. for 10 hours.

<Coating of Phosphor Layer> The prepared phosphor layer coating solution 1 was coated on the undercoat layer of each of the heat-treated samples and untreated samples so that the dry film thickness was 180 μm, and the phosphor layer was coated. Body sheets 1A (without heat treatment), 1B (heat treatment 1), and 1C (heat treatment 2) were produced.

(Phosphor sheet 2A-5A, 2B-5B,
Production of 2C to 5C) Next, the above phosphor sheets 1A, 1
In the preparation of B and 1C, the phosphor sheets 2A to 5A were prepared in the same manner except that the addition amount of the polyester resin was changed so that the dry film thickness of the phosphor layer coating solution 1 became the value shown in Table 1.
A, 2B-5B, and 2C-5C were produced. For each sample,
The amount of phosphor particles per unit area was kept constant.

(Forced Deterioration Treatment of Each Phosphor Sheet) Two parts of the above-prepared phosphor sheet were prepared, part of which was used as a reference sample, and the other part was kept in an atmosphere of 30 ° C. and 80% RH. The treatment was performed for 10 hours, and this was used as a forced deterioration treated sample.

<< Preparation of Moisture-Proof Protective Film >> The following constitution (A) was used as a protective film on the side of the phosphor layer coated surface of each phosphor sheet prepared above.

Structure (A) VMPET12 // VMPET12 // PET12 //
Sealant film PET: Polyethylene terephthalate Sealant film: CPP (casting polypropylene) or LLDPE (low-density linear polyethylene) is used as a heat-fusible film VMPET: Alumina-deposited PET (commercially available: manufactured by Toyo Metalizing Co., Ltd.) The number described after the number indicates the film thickness (μm).

The above "//" means a dry lamination adhesive layer, which means that the thickness of the adhesive layer is 2.5 μm. As the adhesive for dry lamination used, a two-component reaction type urethane adhesive was used. At this time, an organic blue colorant (Pomelo First Blue 3) previously dispersed and dissolved in methyl ethyl ketone was used in the adhesive solution used.
G, manufactured by Hoechst Co., Ltd.) was added to make the entire adhesive layer an excitation light absorption layer. Further, the light transmittance of the excitation light absorption layer was adjusted by adjusting the addition amount at this time.

The protective film on the back surface side of the support of the phosphor sheet is a sealant film / aluminum foil film 9 μm /
A dry laminated film having a constitution of polyethylene terephthalate (PET) 188 μm was used. In this case, the thickness of the adhesive layer was 1.5 μm, and a two-component reactive urethane adhesive was used.

<< Preparation of Radiation Image Conversion Panel >> Each of the phosphor sheets prepared above was cut into a square having a side of 45 cm, and then the peripheral edge portion was impulse-sealed under reduced pressure using the moisture-proof protective film prepared above. Fusion using,
It sealed and produced the radiation image conversion panel. The distance from the fusion portion to the peripheral edge of the phosphor sheet was 1 mm. The heater of the impulse sealer used for fusion bonding had a width of 8 mm.

<< Evaluation of Radiation Image Conversion Panel >> Using each phosphor sheet and each radiation image conversion panel produced as described above, the distribution of isocyanate groups was measured, and the color stability and brightness stability were measured according to the following methods. Was evaluated.

(Measurement of Isocyanate Group Distribution) For each phosphor sheet, the isocyanate group content in a region of a depth of 180 μm from the surface of the phosphor layer was measured by the method described below.

From the phosphor layer surface of each heat-treated and untreated phosphor sheet, using an ultramicrotome, 5
Trimming was sequentially performed as a thin layer having a thickness of 10 μm, and a thin piece having a thickness of 5 μm corresponding to a region having a depth of 177.5 to 182.5 μm was taken out from the surface to quantify the content of the isocyanate group per unit mass.

(Evaluation of discoloration property) With respect to the standard sample and the forced deterioration sample of the phosphor sheet prepared above, the surface of the phosphor layer was visually observed, and the discoloration property was evaluated according to the criteria described below.

⊚: almost no yellowing was observed in both the standard sample and the forced deterioration sample ○: No discoloration was observed in the standard sample, but slight yellowing was observed in the forced deterioration sample Δ: No discoloration in the standard sample Although not observed, some yellowing is observed in the forced deterioration sample x: Slight yellowing is observed in the standard sample, and strong yellowing is observed in the forced deterioration sample. Determined not to.

(Evaluation of Brightness Stability) The brightness of each radiation image conversion panel (also simply referred to as a panel) using the reference sample and the forced deterioration sample as the phosphor sheet was measured by the following method.

The luminance was measured by irradiating each radiation image conversion panel with or without forced deterioration treatment with an X-ray having a tube voltage of 80 kVp, and then irradiating the panel with He-Ne laser light (633 n).
m), the photostimulated luminescence emitted from the phosphor layer is excited by the photodetector (photomultiplier tube with spectral luminance S-5), and its intensity is measured. After defining, the luminance deterioration rate of the panel using the forced deterioration treatment sample with respect to the panel using the reference sample was calculated, and ranked according to the following criteria.

5: Brightness deterioration rate of less than 2% 4: Brightness deterioration rate of 2 to less than 5% 3: Brightness deterioration rate of 5 to less than 10% 2: Brightness deterioration rate of less than 10 to 20% 1: Brightness deterioration rate Is 20% or more and is 3 or more in the above rank, it is determined to be in a practically acceptable range.

Table 1 shows the results obtained as described above.

[0099]

[Table 1]

As is clear from Table 1, the sample of the present invention having an isocyanate group concentration of 0 to 70 ppm contained in the region 180 μm deep from the surface portion of the phosphor layer specified in the present invention was compared with the comparative example. Thus, it can be seen that there is no yellowing of the phosphor surface at the time of production and after storage under high temperature and high humidity conditions, and the brightness stability is excellent. In particular, it can be seen that the effect is further exhibited by applying a heat treatment after coating the undercoat layer on the support.

Example 2 << Preparation of Radiation Image Conversion Panel >> (Preparation of Phosphor Layer Coating Solution 2) 480 g of europium-activated barium fluoroiodide phosphor prepared in Example 1 and no isocyanate groups at both ends Polyurethane resin A (Nipporan 2304, manufactured by Nippon Polyurethane Industry Co., Ltd.), which has not been added, is added to a 1: 1 mixed solvent of methyl ethyl ketone: toluene with 20.0 g as a solid content and dispersed by a propeller mixer to give a viscosity of 25- 30 mPa
* S phosphor layer coating solution 2 was prepared.

(Preparation of Phosphor Layer Coating Liquid 3) Europium-activated barium fluoroiodide phosphor 48 prepared in Example 1
0 g and the above polyurethane resin A (Nipporan 2304 manufactured by Nippon Polyurethane Industry Co., Ltd.) as a solid content 1
Polyurethane resin B (manufactured by Nippon Polyurethane Industry Co., Ltd.) having 0.59 g and isocyanate groups at both ends
Nipporan 5115) as a solid content and 9.41 g were added to a 1: 1 mixed solvent of methyl ethyl ketone: toluene and dispersed by a propeller mixer to give a viscosity of 25 to 3
Phosphor layer coating liquid 3 having 0 mPa · s was prepared. The total isocyanate group amount of the polymer resin used in the phosphor layer coating liquid 3 is 800 ppm.

(Preparation of Phosphor Layer Coating Liquids 4 and 5) In the preparation of the phosphor layer coating liquid 3, the total amount of polyurethane resin A and polyurethane resin B, which are polymer resins, is 20 g.
And adjust the mixing ratio of each resin appropriately,
The total isocyanate group content of the polymer resin is 120
Phosphor layer coating solutions 4 and 5 of 0 ppm and 1500 ppm were prepared.

(Preparation of Phosphor Sheets 6-9) <Coating of Phosphor Layer> On the 250 μm thick carbon-kneaded black polyethylene terephthalate support, the prepared phosphor layer coating solutions 2-5 were prepared. Dry film thickness is 200μ
The coating was performed so as to be m, and phosphor sheets 6 to 9 were manufactured.

(Forced Deterioration Treatment of Each Phosphor Sheet) Two parts of the above-prepared phosphor sheet were prepared, part of which was used as a reference sample, and the other part was kept at 30 ° C. and 80% RH. The treatment was performed for 10 hours, and this was used as a forced deterioration treated sample.

<< Preparation of Radiation Image Conversion Panel >> Each radiation image conversion panel was prepared in the same manner as in Example 1 except that the phosphor sheets 6 to 9 prepared above were used.

<< Evaluation of Radiation Image Conversion Panel >> Using each phosphor sheet and each radiation image conversion panel produced as described above, the discoloration property and the brightness stability were evaluated according to the method described in Example 1. The results obtained are shown in Table 2.

[0108]

[Table 2]

As is clear from Table 2, Samples 6 and 7 made of the polymer resin having the total isocyanate group content of the present invention in the range of 0 to 1000 ppm were compared with those of Comparative Example at the time of production and It can be seen that there is no yellowing on the surface of the phosphor after storage under high temperature and high humidity conditions, and the brightness stability is excellent.

[0110]

Industrial Applicability According to the present invention, it is possible to provide a radiation image conversion panel which prevents yellowing due to heat and moisture absorption during the manufacturing stage and long-term storage and has excellent brightness stability, and a manufacturing method thereof.

Claims (7)

[Claims] 1. A radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, wherein the stimulable phosphor layer contains iodine and has a surface. The radiation image conversion panel is characterized in that the concentration of the isocyanate group contained in the region having a depth of 180 μm from the portion is 0 to 70 ppm. 2. A radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, wherein the stimulable phosphor contains iodine and the binder is Is a polymer resin having an isocyanate group content of 0 to 1000 ppm, which is a radiation image conversion panel. 3. The radiation image conversion panel according to claim 2, wherein the polymer resin has a urethane bond in the main chain. 4. The stimulable phosphor is Eu-added BaFBr.
The radiation image conversion panel according to claim 1, wherein _X I _(1-X) (0 ≦ X <1). 5. A method for producing a radiation image conversion panel having a stimulable phosphor layer containing a stimulable phosphor and a binder on a support, wherein the stimulable phosphor contains iodine,
The binder has an isocyanate group content of 0 to 1000.
A method for producing a radiation image conversion panel, which is produced using a polymer resin having a ppm. 6. The method for manufacturing a radiation image conversion panel according to claim 5, wherein the polymer resin has a urethane bond in the main chain. 7. The stimulable phosphor is Eu-added BaFBr.
_X I _(1-X) (0 ≦ X <1), The method of manufacturing a radiation image conversion panel according to claim 5 or 6, wherein