JP2540363B2 - Radiation image conversion panel and manufacturing method thereof - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a radiation image conversion panel used in a radiation image conversion method utilizing a stimulable phosphor and a method for producing the same.

[Technical Background and Prior Art of the Invention] As an alternative to the conventional radiographic method, for example, a radiation image conversion method using a stimulable phosphor as described in JP-A-55-12145 or the like is known. Are known. This method utilizes a radiation image conversion panel (also referred to as a stimulable phosphor sheet) containing a stimulable phosphor,
Radiation transmitted through the subject or emitted from the subject is absorbed by the stimulable phosphor of the panel, and then the stimulable phosphor is time-series by electromagnetic waves (excitation light) such as visible light and infrared rays. Upon excitation, the radiation energy accumulated in the stimulable phosphor is emitted as fluorescence (stimulated luminescence light), and the fluorescence is photoelectrically read to obtain an electric signal, and the obtained electric signal is obtained. Based on this, the radiation image of the subject or the subject is reproduced as a visible image.

According to this radiographic image conversion method, a radiographic image with a large amount of information can be obtained with a much smaller exposure dose than in the case of a radiographic method using a combination of a conventional radiographic film and an intensifying screen. There is an advantage that you can.
Therefore, this method has a very high utility value in direct medical radiography at the time of X-ray photography particularly for the purpose of medical diagnosis.

The radiation image conversion panel used in the radiation image conversion method has, as a basic structure, a support and a stimulable phosphor layer provided on one surface thereof. In addition, when the phosphor layer is self-supporting, a support is not always necessary. In addition, a transparent protective film is generally provided on the surface of the photostimulable phosphor layer opposite to the support (the surface not facing the support), and the phosphor layer is chemically treated. Protects against severe alteration or physical shock.

The stimulable phosphor layer is generally composed of a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. The stimulable phosphor layer absorbs radiation such as X-ray and then emits excitation light. It has the property of exhibiting stimulated emission upon irradiation.
Therefore, the radiation transmitted through the subject or emitted from the subject is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and the radiation image of the subject or subject is radiated on the panel. It is formed as an accumulated image of energy. This accumulated image can be emitted as stimulated emission light by irradiating the excitation light, and the accumulated image of radiation energy is imaged by photoelectrically reading this stimulated emission light and converting it into an electric signal. It becomes possible to do.

Although the radiographic image conversion method is a very advantageous image forming method as described above, the radiographic image conversion panel used in this method has a high sensitivity like the intensifying screen used in the conventional radiographic method. In addition, it is desired that the image quality has good image quality (sharpness, graininess, etc.).

The sensitivity of the radiation image conversion panel basically depends on the total stimulable emission amount of the stimulable phosphor contained in the panel, and the total luminescence amount depends not only on the emission luminance of the phosphor itself,
It also depends on the content of the phosphor in the phosphor layer. A large content of the phosphor also means a large absorption for radiation such as X-rays, so that higher sensitivity can be obtained and at the same time, image quality (particularly graininess) is improved. on the other hand,
In the case where the phosphor content in the phosphor layer is constant, the layer thickness can be reduced as the phosphor particles are more densely packed, so that the spread of excitation light due to scattering can be reduced. And a relatively high sharpness can be obtained.

The applicant of the present application, as one of the radiation image conversion panels having a phosphor layer densely packed with a phosphor, a radiation image conversion panel in which the porosity of the phosphor layer is reduced by compressing the phosphor layer. And its manufacturing method have already been applied (see JP-A-59-126299, JP-A-59-126300).

In the above-described radiation image conversion panel, the density of the phosphor in the phosphor layer is made higher than that of the conventional radiation image conversion panel by compressing the phosphor layer. As a result, this radiation image conversion panel has an excellent sharpness, but on the other hand, there is a problem that the sensitivity is lowered because the phosphor is partially destroyed by the compression treatment.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a radiation image conversion panel having a high phosphor filling rate and high sensitivity.

Another object of the present invention is to provide a method for manufacturing a radiation image conversion panel capable of increasing the phosphor filling rate while suppressing the decrease in sensitivity due to compression processing.

The above object of the present invention is a support, and a radiation image conversion panel substantially constituted by a phosphor layer comprising a binder and a stimulable phosphor provided on the support, A radiation image conversion panel, wherein the stimulable phosphor particles in the phosphor layer are surface-treated with a titanate-based coupling agent, and a) the stimulable phosphor particles are titanate-based coupling agent. Surface treatment by b), forming a phosphor sheet comprising a binder and the surface-treated stimulable phosphor, c) placing the phosphor sheet on a support and softening the binder And a step of adhering the phosphor sheet on a support while compressing at a temperature or a temperature equal to or higher than a melting point, and a method for producing a radiation image conversion panel, comprising:

Unlike the silane coupling agent, the titanate coupling agent forms an organic monolayer on the inorganic surface to disaggregate and uniformly disperse the phosphor particles, improving the adhesion between the inorganic and organic materials. Has a function to enhance sex.

In the radiation image storage panel of the present invention, the surface of the stimulable phosphor particles is surface-treated with the titanate-based coupling agent and then pressure-treated to increase the filling rate of the phosphor, so that the phosphor particles Are uniformly dispersed, and are compressed in a state in which the affinity between the phosphor surface and the binder resin is improved. Therefore, it is possible to prevent the phosphor particles from destroying each other due to compression. Moreover, in the method for manufacturing the radiation image storage panel of the present invention, a phosphor sheet composed of a phosphor and a binder is prepared in advance, and the phosphor sheet is placed on a support to soften or melt the binder. As described above, since the compression is performed at the same time as the installation on the support, it is possible to further prevent the phosphor from being damaged.

That is, at the time of compression, the phosphor crystal dispersed in the binder that is heated to the softening temperature or the melting point or higher is subjected to pressure with a certain degree of freedom. It can be oriented. Moreover, pressure is applied to the phosphor sheet without fixing it to the support, and the phosphor sheet is placed on the support while being compressed. Therefore, the pressure applied to the phosphor sheet acts to orient the phosphor crystals, and at the same time, the phosphor sheet If is fixed, it works to spread the sheet thinly even under the pressure that destroys the crystals.

 The preferred embodiments of the present invention are listed below.

(1) A radiation image conversion panel, wherein the binder is a thermoplastic elastomer.

(2) The binder has a softening temperature or a melting point of 30 to 300 ° C.
A radiation image conversion panel, which is a thermoplastic elastomer.

(3) The binder has a softening temperature or melting point of 30 to 200 ° C.
A radiation image conversion panel, which is a thermoplastic elastomer.

(4) The binder has a softening temperature or melting point of 30 to 150 ° C.
A radiation image conversion panel, which is a thermoplastic elastomer.

(5) The radiation image conversion panel, wherein the titanate coupling agent is a pale yellow liquid.

(6) A method for producing a radiation image conversion panel, wherein the binder is a thermoplastic elastomer.

(7) The binder has a softening temperature or melting point of 30 to 300 ° C.
A method for producing a radiation image storage panel, which is a thermoplastic elastomer.

(8) The binder has a softening temperature or melting point of 30 to 200 ° C.
A method for producing a radiation image storage panel, which is a thermoplastic elastomer.

(9) The binder has a softening temperature or melting point of 30 to 150 ° C.
A method for producing a radiation image storage panel, which is a thermoplastic elastomer.

(10) A method for producing a radiation image conversion panel, wherein the titanate-based coupling agent is a pale yellow liquid.

(11) A method for producing a radiation image conversion panel, characterized in that, prior to the step c), an adhesive layer and / or a light reflecting layer is provided on the support in advance.

(12) A method for producing a radiation image conversion panel, characterized in that the compression in the step c) is performed using a calendar roll.

(13) A method for producing a radiation image conversion panel, wherein the compression in the step c) is performed at a pressure of 50 Kgw / cm ² or more.

[Structure of the Invention] The radiation image conversion panel of the present invention can be manufactured, for example, by the method of manufacturing the radiation image conversion panel of the present invention described below.

The method for producing a radiation image conversion panel of the present invention comprises a) a step of surface-treating stimulable phosphor particles with a titanate coupling agent, b) a binder and the surface-treated stimulable phosphor. Forming a phosphor sheet, c) placing the phosphor sheet on a support, and adhering the phosphor sheet on the support while compressing at a temperature above the softening temperature or melting point of the binder, It consists of

 First, step a) will be described.

In step a), the stimulable phosphor particles are surface-treated with a titanate coupling agent.

The phosphors used in the present invention will be described below.

The stimulable phosphor is a phosphor that emits stimulated emission when irradiated with excitation light after being irradiated with radiation as described above, but from a practical viewpoint, the wavelength is in the range of 400 to 900 nm. A phosphor that exhibits stimulated emission in the wavelength range of 300 to 500 nm by excitation light is desirable. Examples of stimulable phosphors used in the radiation image conversion panel of the present invention include BaSO ₄ : AX described in JP-A-48-80487 and JP-A-48-80489. SrSO ₄ : AX
In phosphor represented, Li is described in _{JP-A-53-39277 2 B 4 O 7: Cu} ,
Ag, Li ₂ O · (B ₂ O
₂ ) _x : Cu and Li ₂ O. (B ₂ O ₂ ) _x : Cu, Ag, SrS: C described in US Pat. No. 3,859,527.
e, Sm, SrS: Eu, Sm, ThO ₂ : Er, and La ₂ O ₂ S: Eu, Sm, ZnS: Cu, Pb described in JP-A-55-12142.
BaO.xAl ₂ O ₃ : Eu (where 0.8 ≦ x ≦ 10) and M ^II
O.xSiO ₂ : A (where M ^II is Mg, Ca, Sr, Zn, Cd, or Ba, and A is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or
Mn, and x is 0.5 ≦ x ≦ 2.5), which is described in JP-A-55-12143 (Ba _1-Xy , M
g _X , Ca _y ) FX: aEu ²⁺ (where X is at least one of Cl and Br, and x and y are 0 <x + y ≦ 0.
6, and xy ≠ 0, a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ), and LnOX: xA described in JP-A-55-12144 (where Ln is La, At least one of Y, Gd, and 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), described in JP-A-55-12145 (Ba _1-X , M ²⁺
_X ) FX: yA (where M ²⁺ 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, Pr, Ho, N
at least one of d, Yb, and Er, and x
Is 0 ≦ x ≦ 0.6 and y is 0 ≦ y ≦ 0.2), and BaFX: xCe · x described in JP-A-55-843897.
Phosphor represented by yA M ^II FXxA described in JP-A-55-160078:
yLn [where M ^II is at least one of Ba, Ca, Sr, Mg, Zn, and Cd; A is BeO, MgO, CaO, SrO, BaO, Z
nO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ ZrO ₂ , GeO
₂ , at least one of SnO ₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , Ln is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Yb, E
at least one of r, Sm, and Gd, X is Cl, B
at least one of r and I, wherein x and y are respectively 5 × 10 ⁻⁵ ≦ x ≦ 0.5 and 0 <y ≦ 0.2]. No. 116777 (Ba _1-X , M
^II _X ) F ₂ · aBaX ₂ : yEu, zA [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, A is at least one of zirconium and scandium, and 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
Phosphor represented by a composition formula of In is] are described in _{JP-A-57-23673 (Ba 1-X, M} II
_X ) F ₂ · aBaX ₂ : yEu, zB [where M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is chlorine, bromine,
And at least one of iodine and a, x,
y and z are respectively 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 1
0 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 10 ⁻² ], the phosphor represented by the composition formula of JP-A-57-23675 (Ba _1-X). , M ^II
_X ) F ₂ aBaX ₂ : yEu, zA [where M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, X is chlorine, bromine,
And at least one of iodine and A is at least one of arsenic and silicon, and a, x, y and z are respectively 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦
2 × 10 ⁻¹ and 0 <z ≦ 5 × 10 ⁻¹ ], and M ^III OX: xCe described in JP-A-58-69281.
[However, M ^III is Pr, Nd, Pm, Sm, Eu, Tb, Dy, Ho, E
at least one trivalent metal selected from the group consisting of r, Tm, Yb, and Bi, X is one or both of Cl and Br, and x is 0 <x <0.1] A phosphor represented by the following composition formula: Ba _1-X M _{X / 2} described in JP-A-58-206678.
L _{X / 2} FX: _y Eu ²⁺ [where M is Li, Na, K, Rb, and C
represents at least one alkali metal selected from the group consisting of s; L is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, G
d, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, In, and T
represents at least one trivalent metal selected from the group consisting of l; X represents at least one halogen selected from the group consisting of Cl, Br, and I; and x represents 10 ^-2
.Ltoreq.x.ltoreq.0.5, y is 0 <y.ltoreq.0.1]. BaFX.xA: yE described in JP-A-59-27980.
u ^{2+ wherein} X is at least one halogen selected from the group consisting of Cl, Br, and I; A is a calcined product of a tetrafluoroborate compound; and x is 10
^-6 ≤ x ≤ 0.1, y is 0 <y ≤ 0.1] xM ₃ (PO ₄ ) described in JP-A-59-38278
₂・ NX ₂ : yA, M ₃ (PO ₄ ) ₂ : yA and nReX ₃・ mAX ′ ₂ : xEu,
nReX ₃・ mAX ′ ₂ : xEu, ySm, M ^I X ・ aM ^II X ′ ₂・ bM ^III X ″ ₃ : c
A phosphor represented by A, BaFXxA: yE described in JP-A-59-47289.
u ²⁺ [where X is at least one halogen selected from the group consisting of Cl, Br and I; A is monovalent or divalent hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid] A calcined product of at least one compound selected from the group of hexafluoro compounds consisting of salts of valent metals; and x is 10 ⁻⁶ ≦ x ≦
0.1, y is 0 <y ≦ 0.1], a phosphor represented by the composition formula, BaFX.xNa described in JP-A-59-56479.
X ′: aEu ²⁺ [where X and X ′ are Cl, B
r and at least one of I, and x and a are respectively 0 <x ≦ 2 and 0 <a ≦ 0.2]
The phosphor represented by the composition formula of M ^II FX.xNa described in JP-A-59-56480.
X ′: yEu ²⁺ : zA [where M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; X and X ′ are Cl, Br, and I, respectively. At least one halogen selected from the group consisting of: A
Is at least one fiber metal selected from V, Cr, Mn, Fe, Co, and Ni; and x is 0 <x ≦ 2,
y is 0 <y ≦ 0.2, and z is 0 <z ≦ 10 ^-2 a] phosphor represented by a composition formula of, M ^II FX · aM that is described in JP-A-59-75200
^I X ′ ・ bM ′ ^II X ″ ₂・ cM ^III X ₃・ xA: yEu ²⁺ [However, M
^II is Ba, Sr, and is at least one alkaline earth metal selected from the group consisting of Ca; M ^I is Li, Na, K, R
b, and at least one alkali metal selected from the group consisting of Cs; M ′ ^II is at least one divalent metal selected from the group consisting of Be and Mg; M ^III is Al, G
a, In, and at least one trivalent metal selected from the group consisting of Tl; A is a metal oxide; X is Cl, Br,
X ', X ", and X are at least one halogen selected from the group consisting of F, Cl, Br, and I; and a is 0 ≦ a ≦ 2, b is 0 ≦ b ≦ 1
0 ^-2 and c are 0≤c≤10 ^-2 and a + b + c≥10 ^-6 ;
x is 0 <x ≦ 0.5 and y is 0 <y ≦ 0.2], the phosphor represented by the composition formula M ^II X ₂ · aM ^II described in JP-A-60-84381.
X ′ ₂ : xEu ²⁺ [where M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X and X ′ are selected from the group consisting of Cl, Br and I A stimulable phosphor represented by a composition formula of at least one halogen and X 、 X ′; and a is 0.1 ≦ a ≦ 10.0 and x is 0 <x ≦ 0.2. M ^II FX ・ aM ^I described in JP-A-60-101173
X ′: xEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; 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; X 'is F,
At least one halogen selected from the group consisting of Cl, Br and I; and a and x are each 0 ≦ a
≦ 4.0 and 0 <x stimulable phosphor represented by a composition formula of ≦ 0.2 is], M ^I X are described in JP-A-62-25189: xBi [However, M ^I is Rb and Cs Is at least one alkali metal selected from the group consisting of; X is at least one halogen selected from the group consisting of Cl, Br and I; and x is a number in the range 0 <x ≦ 0.2] Examples thereof include stimulable phosphors represented by a composition formula.

Further, M described in JP-A-60-84381 described above
^II X ₂・ aM ^II X ′ ₂ : xEu ²⁺ Stimulable phosphor contains the following additives in the following ratio per mole of M ^II X ₂・ aM ^II X ′ ₂ : Is also good.

JP bM ^I X that are described in 60-166379 JP "(where, M ^I is at least one alkali metal selected from the group consisting of Rb and Cs, X 'is F, Cl, Br and I At least one halogen selected from the group consisting of: and b is 0 <b ≦ 10.0);
BKX ″ · cMgX ₂ · dM ^III X described in Japanese Patent No. 1483
′ ₃ (where M ^III is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu,
X ″, X and X ′ are all F, Cl, Br and I
Is at least one halogen selected from the group consisting of, and b, c and d are each 0 ≦ b ≦ 2.0,
0 ≦ c ≦ 2.0, 0 ≦ d ≦ 2.0, and 2 × 10 ⁻⁵ ≦ b
+ C + d); yB described in JP-A-60-228592 (where y is 2 × 10 ⁻⁴ ≦ y ≦ 2 × 10 ⁻¹ ); JP-A-60-228593. BA as described (where A is at least one oxide selected from the group consisting of SiO ₂ and P ₂ O ₅ , and b is 10 ⁻⁴ ≦ b ≦ 2 ×
10 ^-1 is); bSiO that are described in JP 61-120883 Laid (where, b is 0 <b ≦ 3 is a × 10 ^-2); described in JP-A No. 61-120885 Laid BSnX ″ ₂ (where X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I, and b is <b ≦ 10
^-3 ); described in JP-A-61-235486
bCsX ″ · cSnX ₂ (wherein X ″ and X are at least one halogen selected from the group consisting of F, Cl, Br and I, and b and c are respectively
0 <b ≦ 10.0 and 10 ⁻⁶ ≦ c ≦ 2 × 10 ⁻² ); and bCsX ″ · yL described in JP-A No. 61-235487.
n 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, Ho, Er, Tm, Yb and at least one rare earth element selected from the group consisting of Lu, and b and y are each 0 <b ≦ 10.0
And 10 ⁻⁶ ≦ y ≦ 1.8 × 10 ⁻¹ ).

Among the above stimulable phosphors, a divalent europium-activated alkaline earth metal halide-based phosphor and a cerium-activated rare earth oxyhalide-based phosphor are particularly preferable because they exhibit high-luminance stimulable emission. However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphor, and may be any phosphor that exhibits stimulated emission when irradiated with excitation light after irradiation with radiation. It may be.

The stimulable phosphor as described above is surface-treated with a titanate coupling agent.

The titanate-based coupling agent has a portion of a group that gives affinity to the resin or that reacts with the resin and a portion of the hydrophilic group.Unlike conventional silane-based coupling agents, organic monomolecules are present on the inorganic surface. By forming a film, the particles are agglomerated to uniformly disperse the fine particles, and further, the organic substance and the inorganic substance are well adhered to each other, and the workability is enhanced. Examples of such titanate-based coupling agents include tetraoctyl bis (di-tridecyl phosphite) titanate, bis (dioctyl virophosphate) oxyacetate titanate, bis (dioctyl virophosphate) ethylene titanate, isopropyl, Trioctanoyl titanate, isopropyl dimethacryl isostearoyl titanate, isopropyl
Triisostearoyl titanate, isopropyl tris (N-aminoethyl-aminoethyl) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (di-tridecyl) phosphite cyanate, isopropyl tridodecyl Benzene, sulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri (dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, tetraisopropyl bis (dioctyl phosphite) titanate, etc. can be mentioned. . Among these, pale yellow liquid titanate coupling agents such as tetraoctyl bis (di-tridecyl phosphite) titanate, bis (dioctyl bilophosphate) oxyacetate titanate and bis (dioctyl bilophosphate) ethylene titanate. Is preferable since the color of the coupling agent does not have a bad influence on the excitation light and the emitted light.

The surface treatment method can be appropriately selected depending on the phosphor and the coupling agent from conventionally known treatment methods such as a dry method direct treatment, a solvent treatment, and a water slurry treatment.

 Next, the step b) will be described.

First, the phosphor surface-treated by the above step b) and the binder are added to a suitable solvent, and they are mixed sufficiently to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in the binder solution. Prepare.

As the binder, a thermoplastic elastomer having elasticity at normal temperature and having fluidity when heated is suitably used. Examples of the thermoplastic elastomer include polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, ethylene vinyl acetate, polyvinyl chloride, natural rubber, fluorine rubber, polyisoprene, chlorinated polyethylene, styrene-butadiene rubber, and silicone rubber. Can be mentioned.

Among the above thermoplastic elastomers, those having a softening temperature or a melting point of 30 ° C to 300 ° C are generally used, but those having a softening temperature of 30 ° C to 200 ° C are preferable, and those having a temperature of 30 ° C to 150 ° C are preferably used. More preferred.

Examples of the solvent for preparing the coating liquid include lower alcohols such as methanol, ethanol, n-propanol and n-butanol; hydrocarbons containing chlorine atoms such as methylene chloride and ethylene chloride; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. Esters of lower fatty acids such as methyl acetate, ethyl acetate and butyl acetate with lower alcohols; ethers such as dioxane, ethylene glycol monoethyl ether and ethylene glycol monomethyl ether; and mixtures thereof.

The mixing ratio between the binder and the stimulable phosphor in the coating solution is
Depending on the characteristics of the intended radiation image conversion panel, the type of phosphor, etc., generally, the mixing ratio of the binder and the phosphor is selected from the range of 1: 1 to 1: 100 (weight ratio), and It is particularly preferable to select from the range of 1: 8 to 1:40 (weight ratio).

The coating solution has a dispersant for improving the dispersibility of the phosphor in the coating solution, and also for improving the binding force between the binder and the phosphor in the formed phosphor layer. Various additives such as a plasticizer may be mixed. Examples of dispersants used for such purposes include:
Examples include phthalic acid, stearic acid, caproic acid, and lipophilic surfactants. Examples of plasticizers include phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalyl glycolate, butyl phthalyl butyl glycolate, etc. And a polyester of polyethylene glycol and an aliphatic dibasic acid, such as a polyester of triethylene glycol and adipic acid, a polyester of diethylene glycol and succinic acid, and the like.

The coating liquid containing the phosphor and the binder prepared as described above is then uniformly applied to the surface of the temporary support for sheet formation to form a coating film of the coating liquid. This coating operation can be performed by using an ordinary coating means such as a doctor blade, a roll coater or a knife coater.

The temporary support is, for example, a glass, a metal plate, various materials used as a support for an intensifying screen (or an intensifying screen) in a conventional radiographic method, or a support for a radiation image conversion panel. Can be arbitrarily selected from known materials. Examples of such materials include films of plastic substances such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate, metal sheets such as aluminum foil, aluminum alloy foil, ordinary paper, baryta paper, resin. Examples thereof include coated paper, pigment paper containing pigments such as titanium dioxide, paper sized with polyvinyl alcohol and the like, and plates or sheets of ceramics such as alumina, zirconia, magnesia and titania.

A coating solution for forming a phosphor layer is applied onto a temporary support, dried, and then peeled from the temporary support to obtain a phosphor sheet which will be a phosphor layer of a radiation image conversion panel. Therefore, it is preferable to apply a release agent on the surface of the temporary support in advance so that the formed phosphor sheet can be easily peeled off from the temporary support.

Next, step c) in the method of manufacturing a radiation image storage panel of the present invention will be described.

First, apart from the phosphor sheet formed as described above,
A support for the radiation image conversion panel is prepared. This support can be arbitrarily selected from the same material as the temporary support used when forming the phosphor sheet.

In a known radiation image conversion panel, 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, graininess) of the radiation image conversion panel. The surface of the side support is coated with a polymer substance such as gelatin to form an adhesion-imparting layer, or a light-reflecting layer made of a light-reflecting substance such as titanium dioxide, or a light-absorbing substance made of a light absorbing substance such as carbon black. It is known to provide an absorbing layer and the like.
The support used in the present invention can also be provided with these various layers, and their configuration can be arbitrarily selected according to the desired purpose and application of the radiation image conversion panel.

Further, as described in JP-A-59-200200, for the purpose of improving the sharpness of the image obtained, the surface of the support on the phosphor layer side (the surface of the support on the phosphor layer side is When an adhesion-providing layer, a light-reflecting layer, a light-absorbing layer, or the like is provided, it means the surface thereof), and minute irregularities may be formed.

The phosphor sheet obtained in step b) is placed on a support and bonded on the support while being compressed at the softening temperature or the melting point of the binder or higher.

Examples of the compression device used for the compression treatment of the present invention include commonly known ones such as a calender roll and a hot press. For example, the compression treatment with a calender roll is carried out by placing the phosphor sheet obtained in step b) on a support and passing it at a constant speed between rollers heated to the softening temperature or melting point of the binder or higher. . However, the compression device used in the present invention is not limited to these,
Any material may be used as long as it can compress the sheet while heating.

The pressure during compression is generally 50 kgw / cm ² or more.

The porosity of the phosphor layer formed on the support as described above can be theoretically determined by the following formula (I).

(However, V: total volume of phosphor layer Vair: air volume in phosphor layer A: total weight of phosphor layer ρ _X : density of phosphor ρ _y : density of binder ρ air: density of air a: fluorescence Weight of body b: Weight of binder) Further, in the formula (I), since ρair is almost 0, the formula (I) can be approximately represented by the following formula (II).

(However, the definitions of V, Vair, A, ρ _X , ρ _y , a, and b are the same as those in the formula (I).) In the present invention, the porosity of the phosphor layer is calculated by the formula (II). I asked.

Further, the filling rate of the phosphor can be obtained by the following formula (III).

(However, the definitions of V, Vair, A, ρ _X , ρ _y , a, and b are the same as those in the formula (I).) In a normal radiation image conversion panel, as described above, the side in contact with the support is A transparent protective film for physically and chemically protecting the phosphor layer is provided on the surface of the phosphor layer on the opposite side. Such a transparent protective film is preferably installed also in the radiation image storage panel according to the present invention.

The transparent protective film may be, for example, a cellulose derivative such as cellulose acetate or nitrocellulose; or a transparent polymer material such as polymethylmethacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, vinyl chloride / vinyl acetate copolymer. It can be formed by a method in which a solution prepared by dissolving a high-molecular substance in a suitable solvent is applied to the surface of the phosphor layer. Alternatively, polyethylene terephthalate,
A plastic sheet made of polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide, etc .; and a protective film forming sheet such as a transparent glass plate are separately formed and adhered to the surface of the phosphor layer by using an appropriate adhesive. It can also be formed by the method of.

The thickness of the protective film is generally in the range of about 0.1 to 20 μm.

Furthermore, in order to improve the sharpness of the obtained image,
A colored layer that absorbs excitation light but does not absorb stimulated emission light may be added to at least one of the above layers (see JP-B-59-23400).

Next, examples of the present invention will be described. However, each of these examples does not limit the present invention.

[Example 1] Phosphor: BaFBr _0.9 I _0.1 : Eu ²⁺ 100 g was dispersed in 50 g of solvent: 2-propanol, and a titanate coupling agent: tetraoctylbis (di-tridecylphosphite) titanate [ Brenact KR46B manufactured by Ajinomoto Co., Inc.]
0.25 g (0.5 wt.% Of solvent) was added. This was mixed with a roller mill for 4 hours, classified, and dried at 150 ° C. under reduced pressure.

Next, as a coating solution for forming a phosphor sheet, the phosphor that has been subjected to the above treatment: 100 g Binder: Polyurethane (Sumitomo Bayer Urethane Co., Ltd. Desmolak TPKL-5
2625 [Solid content 40%]) …… 22.5g Yellowing inhibitor: Bisphenol A type epoxy resin …… 1.0g is added to a 1: 1 mixed solvent of methyl ethyl ketone and 2-propanol and dispersed with a propeller mixer to obtain a viscosity. Is 30
A coating solution of PS (25 ° C.) was prepared (binder / phosphor ratio = 1 /
20). This was applied onto polyethylene terephthalate (temporary support, thickness 180 μm) coated with a silicone-based release agent, dried and then peeled from the temporary support to form a phosphor sheet.

On the other hand, as a coating liquid for forming the light reflecting layer, BaFBr (containing 90% of particles having a particle diameter in the range of 1 to 5 μm) ...
… 214 g Soft acrylic resin solid content 25.7 g Epoxy resin …… 10.7 g Nitrocellulose (nitrification degree 11.5%, solid content 10% by weight)…
... 64 g was added to methyl ethyl ketone and dispersed by a propeller mixer to prepare a dispersion liquid having a viscosity of 25 to 35 PS (25 ° C).

Separately, as a coating liquid for forming an undercoat layer, soft acrylic resin solid content 90 g nitrocellulose ... 50 g was added to methyl ethyl ketone, dispersed and mixed to give a viscosity of 3
A dispersion of ~ 6PS (25 ° C) was prepared.

A 300 μm thick polyethylene terephthalate (support) is placed horizontally on a glass plate, and the above undercoat layer forming coating solution is uniformly applied on the support using a doctor blade, and then gradually from 25 ° C to 100 ° C. The coating film was dried by elevating the temperature to form an undercoat layer on the support (coating film thickness: 15 μm). Further, the above-mentioned coating solution for forming a light reflection layer was applied (thickness of the coating film: 60 μm), and dried similarly to form an undercoat layer and a light reflection layer on the support. The phosphor sheet prepared first was placed on this, and compression was performed.

The compression was continuously performed using a calender roll at a pressure of 400 Kgw / cm ² and a temperature of 80 ° C. With this compression,
The phosphor sheet and the light-reflecting layer on the support were completely fused.

After the compression, a transparent film of polyethylene terephthalate (thickness 10 μm) coated with a polyester diameter adhesive on one side was adhered with the adhesive side facing down to form a transparent protective film.

As described above, a radiation image conversion panel composed of the support, the undercoat layer, the light reflection layer, the phosphor layer, and the transparent protective film was manufactured.

[Comparative Example 1] In Example 1, instead of the titanate coupling agent, a silane coupling agent: γ-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-Etsu Chemical Co., Ltd.)
A radiation image conversion panel composed of a support, an undercoat layer, a light reflection layer, a phosphor layer, and a transparent protective film was produced in the same manner as in Example 1 except that 0.25 g was used.

[Comparative Example 2] A support, an undercoat layer, a light-reflecting layer were prepared in the same manner as in Example 1 except that the phosphor was not surface-treated.
A radiation image conversion panel including a phosphor layer and a transparent protective film was manufactured.

Evaluation of Radiation Image Conversion Panel The phosphor filling rate in the phosphor layer of each of the radiation image conversion panels of Examples and Comparative Examples manufactured as described above was determined by the formula (III). However, the density of the phosphor is
And 5.1 g / cm ^3, the density of the binding agent was set to 1.14 g / cm ^3.

After irradiating each of the above radiation image conversion panels with X-rays of a tube voltage of 80 KVp, He-Ne laser light (wavelength: 632.8n
It was excited by m) and the stimulated luminescence amount of each panel was measured.

 The results are shown in Table 1.

The stimulated luminescence amount was expressed as a relative value with the stimulated luminescence amount of the panel of Comparative Example 1 as 100.

Table 1 Photostimulated luminescence amount Phosphor filling rate (%) Example 1 107 73.4 Comparative example 1 100 70.6 Comparative example 2 98 70.5 As is apparent from Table 1, the radiation image storage panel of the present invention has a phosphor filling rate. It is found that the light emission is high and the stimulated emission is high. It can also be seen that the method for manufacturing the radiation image storage panel of the present invention can increase the phosphor filling rate while suppressing the sensitivity decrease due to the compression treatment.

Claims (2)

(57) [Claims] 1. A radiation image conversion panel substantially composed of a support and a phosphor layer comprising a binder and a stimulable phosphor provided on the support, wherein the phosphor layer. A radiation image conversion panel, wherein the stimulable phosphor particles therein are surface-treated with a titanate coupling agent. 2. A) a step of surface-treating stimulable phosphor particles with a titanate coupling agent, b) a step of forming a phosphor sheet comprising a binder and the surface-treated stimulable phosphor. And c) a step of placing the phosphor sheet on a support and adhering the phosphor sheet on the support while compressing at a softening temperature or a melting temperature of the binder or higher. Radiation image conversion panel manufacturing method.