JP2002207099A - Radiation luminescent panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the transfer durability and antifouling and mar-proof properties of a radiation luminescent panel. SOLUTION: A protective film 13 of a radiation luminescent panel formed by stacking a phosphor layer 12 and the protective film 13 on a support 11 in the order mentioned is laden with a film-forming resin, a reactant type silicone that reacts with it and two kinds of white powder; the average particle size of the smaller one ranges between 0.4 μm and 0.8 μm and that of the larger one between 1 μm and 2.5 μm.

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 used in a radiation image conversion method using a stimulable phosphor, and a method for converting transmitted radiation into visible light and / or ultraviolet radiation by the phosphor. The present invention relates to a radiation-emitting panel such as an intensifying screen for X-ray photography.

[0002]

2. Description of the Related Art As an alternative to the conventional radiographic method, there is known a radiation image conversion method using a stimulable phosphor as described in, for example, JP-A-55-12145. This method uses a radiation image conversion panel (a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the stimulable phosphor of the panel. And then stimulating the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time-series manner, so that the radiation energy accumulated in the stimulable phosphor is (Stimulated emission light), and the fluorescence is photoelectrically read to obtain an electric signal.
Then, a radiation image of the subject or the subject is reproduced as a visible image based on the obtained electric signal. The panel after reading is prepared for the next photographing after the remaining image is erased. That is, the radiation image conversion panel is used repeatedly.

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 the radiographic method using a combination of a conventional radiographic film and an intensifying screen. There is an advantage that it can be obtained. Furthermore, in contrast to the conventional radiographic method, which consumes radiographic film for each photographing operation, this radiographic image conversion method uses a radiographic image conversion panel repeatedly, which is advantageous in terms of resource conservation and economic efficiency. It is.

A radiation image conversion panel used in a radiation image conversion method basically includes a support and a phosphor layer provided on the surface thereof, except when the phosphor layer has a self-supporting property. Things. Since the phosphor contained in the phosphor layer has a property of emitting light when irradiated with excitation light after absorbing radiation such as X-rays, the radiation transmitted through the subject or emitted from the subject is Light is emitted instantaneously in proportion to the radiation dose, or is absorbed by the emitting phosphor layer and stored as an accumulated image. When the phosphor is stimulable, this accumulated image can be emitted as stimulating light by irradiating with excitation light, and this light is converted into an electric signal by a photoelectric element to accumulate radiation energy. Images can be imaged.

[0005] A protective film is usually provided on the surface of the stimulable phosphor layer (the surface not facing the support) to protect the phosphor layer from chemical alteration or physical impact. are doing. The protective film is formed by applying a solution prepared by dissolving a transparent organic polymer substance such as a cellulose derivative or polymethyl methacrylate in an appropriate solvent onto the phosphor layer, or polyethylene. An organic polymer film such as terephthalate or a sheet for forming a protective film such as a transparent glass plate is separately formed and provided on the surface of the phosphor layer using an appropriate adhesive, or an inorganic compound is deposited on the phosphor by vapor deposition or the like. Those formed on a layer are known. Among them, the protective film formed by coating has advantages that it generally has a strong adhesive strength to the phosphor layer and can be manufactured by a relatively simple process.

However, if such a radiation image conversion panel having a protective film formed by coating is used repeatedly, the radiation image conversion panel may be damaged due to, for example, abrasion on the surface of the protective film. The quality of the radiation image to be formed tends to gradually decrease. Since it is desired that the radiation image conversion panel also provides an image having high sensitivity and good image quality (sharpness, granularity, etc.), similarly to the conventional radiographic method, it is desired that the above-mentioned scratches Preventing occurrence is extremely important.

As a protective film capable of preventing a decrease in the sensitivity of the radiation image conversion panel due to repeated use as described above, the present applicant has already formed a film-forming resin and a polysiloxane skeleton-containing oligomer or a perfluoroalkyl group-containing oligomer. (Japanese Patent No. 2715189) and those further containing white powder (JP-A-62-247298,
-82899). These protective films had a sufficient effect when used repeatedly within 1,000 times.

[0008]

However, in the case of a protective film which merely contains a polysiloxane skeleton-containing oligomer or a perfluoroalkyl group-containing oligomer and does not form a molecular bond in the film, the surface of the protective film repeats itself. As a result of contact with the surface of the object, the oligomer tends to gradually decrease as it is scraped off from the protective film, and after repeated use increased from several thousand times to more than 10,000 times in recent years,
Since the surface is liable to be stained or scratched, resulting in deterioration of the finally obtained radiation image or deterioration of the quality of image information related to the radiation image, further improvement of the durability of the protective film is desired. I have.

The present invention has been made in view of the above circumstances, and is capable of coping with an increase in the number of repeated use of a radiation image conversion panel in recent years. It is an object to provide a conversion panel.

[0010]

According to a radiation emitting panel of the present invention, in a radiation emitting panel having a phosphor layer and a protective film, the protective film reacts with a film forming resin and the film forming resin. A reactive silicone and two kinds of white powders having different average particle sizes, wherein both of the two kinds of white powders have an average particle size of 0.3 μm or more,
In addition, the thickness is not more than 1.5 times the protective film thickness.

A radiation-emitting panel is a radiation image conversion panel containing a stimulable phosphor or an X-ray for converting transmitted radiation into visible light and / or ultraviolet radiation using a non-stimulable phosphor. This is a broad concept including intensifying screens for photographs. The protective film preferably has a thickness in the range of 0.7 to 10 μm, more preferably 1 to 5 μm.

The white powder means a powder that does not absorb light of a specific wavelength at a wavelength of 400 to 800 nm. The particle size distribution of the two types of white powders is preferably as small as possible and monodisperse. Specifically, the ratio of the particle size at a cumulative weight of 25% to the particle size at a cumulative weight of 75% (D25 / D
75) is preferably 5 or less, more preferably 3 or less, and further preferably 2 or less.

The average particle size of the two types of white powders is the larger average particle size than the smaller average particle size.
It is preferably 1.5 times or more, more preferably,
Desirably, the smaller average particle size is in the range of 0.4 to 0.8 μm and the larger average particle size is in the range of 1 to 2.5 μm.

The weight ratio between the smaller average particle size of the two types of white powder and the larger average particle size is 1
0:90 to 95: 5, preferably 50:50 to 90:10
Is more preferable. It is preferable that the white powder is contained in an amount of 1 to 120% by weight based on the film-forming resin.

[0015]

According to the radiation-emitting panel of the present invention, the protective film comprises a film-forming resin, a reactive silicone which has reacted with the film-forming resin, and two kinds of white powders having different average particle sizes. Since the average particle size of these two types of white powders is both 0.3 μm or more and 1.5 times or less of the protective film thickness, radiation emission excellent in transport durability, antifouling property and scratch resistance is achieved. It can be a panel.

That is, in the conventional protective film, the entire surface of the protective film repeatedly comes into contact with the surface of another object, and as a result, the oligomer is gradually reduced by being scraped off from the protective film and the like. It has been found that scratches are likely to occur, resulting in deterioration of the finally obtained radiation image or deterioration of the quality of image information related to the radiation image, but the protective film of the radiation-emitting panel of the present invention has an average particle size of Of the two different types of white powder,
When the projections of the large particles (larger average particle size) come into contact with the surface of another object (member), the contact between the entire surface of the protective film and the member is suppressed, and the film-forming resin is removed from the protective film. Thus, a radiation-emitting panel having excellent transport durability and scratch resistance can be obtained.

Further, since the light is effectively scattered by the small particles (the one having a smaller average particle size), the rainbow unevenness of the protective film can be effectively suppressed, and the deterioration of the image quality of the radiation-emitting panel can be prevented. can do.

By setting the average particle size of the two kinds of white powders to be at least 1.5 times the average particle size of the smaller average particle size, the average particle size of the smaller white powder can be increased to 0.4 to more. By setting the average particle size in the range of 0.8 μm and the larger one in the range of 1 to 2.5 μm, or by setting the weight ratio between the smaller and larger average particle sizes of the two types of white powder to 10:90. When the white powder is contained in the range of 1 to 120% by weight based on the film-forming resin, The effect can be further improved.

By setting the protective film thickness in the range of 0.7 to 10 μm, and more preferably in the range of 1 to 5 μm, it is possible to suppress a decrease in image sharpness.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. In the case where the phosphor layer has self-supporting properties, a support is not required. However, in this embodiment, a radiation-emitting panel having a phosphor layer, a support, and a protective film, which is a general configuration of a radiation-emitting panel, is used. This will be described using a panel as an example.

FIG. 1 is a partial sectional view of a radiation-emitting panel showing a first embodiment of the present invention. As shown in FIG. 1, a radiation-emitting panel 10 according to the present invention includes a support 11, a phosphor layer 12 laminated on a support 11, and a protective film 13 on the phosphor layer 12.
Are laminated. Although not shown,
It is preferable that an edge portion of the radiation-emitting panel is provided with an edge in order to absorb moisture of the phosphor layer and to give strength to the radiation-emitting panel.

Next, each layer of the radiation-emitting panel of the present invention will be described in more detail in the order of the phosphor layer, the support, and the protective film. First, the case where the phosphor of the phosphor layer of the radiation-emitting panel of the present invention is a stimulable phosphor will be described. The stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then irradiated with excitation light as described above, but the wavelength is in the range of 400 to 900 nm from a practical viewpoint. It is desirable that the phosphor be a phosphor that shows stimulated emission in a wavelength range of 300 to 500 nm by the excitation light. Examples of the stimulable phosphor used in radiation image conversion panel of the present invention are described in KOKOKU 7-84588 Patent like, the general formula _{(M 1-f · M f} I) X · bM III X3 ″: CA
The stimulable phosphor represented by (I) is preferred. The M ^I in the formula (I) in terms of stimulated emission luminance, Rb, C
Na and K containing s and / or Cs are preferred, and at least one alkali metal selected from Rb and Cs is particularly preferred. M ^III is preferably at least one trivalent metal selected from Y, La, Lu, Al, Ga and In. X ″ is preferably at least one halogen selected from F, Cl and Br. The b value representing the content of M ^III X3 ″ is preferably selected from the range of 0 ≦ b ≦ 10 ⁻² .

In the general formula (I), the activator A is
At least one metal selected from the group consisting of Eu, Tb, Ce, Tm, Dy, Ho, Gd, Sm, Tl and Na is preferable, and especially Eu, Ce, S
At least one metal selected from m, Tl and Na is preferred. The C value representing the amount of the activator is 10 ⁻⁶ <C <0.1.
It is preferable from the viewpoint of photostimulated light emission luminance.

Further, the following stimulable phosphors can also be used. U.S. patents listed in the 3,859,527 Pat SrS: Ce, Sm, SrS: Eu, Sm, ThO 2: Er, and La ₂ O ₂
S: Eu, Sm,

ZnS: C described in JP-A-55-12142
u, Pb, BaO.xAl ₂ O ₃ : Eu (0.8 ≦ x ≦ 10) and M ^II O.xSiO ₂ : A (where M ^II is Mg, Ca, Sr, Zn, C
d or Ba, and A is Ce, Tb, Eu, Tm, Pb, Tl, Bi
Or Mn, and x is 0.5 ≦ x ≦ 2.5),

Japanese Patent Application Laid-Open No. Sho 55-12143 discloses (Ba
_1-Xy , Mg _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, and a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ),

LnOX described in JP-A-55-12144:
xA (where Ln is at least one of La, Y, Gd, and Lu, X is at least one of Cl and Br, and A is
At least one of Ce and Tb, and x is 0
<X <0.1),

It is described in JP-A-55-12145 (B
a _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 Are Eu, Tb, Ce, Tm, Dy, Pr, H
at least one of o, Nd, Yb and Er, and x
Is 0 ≦ x ≦ 0.6, y is 0 ≦ y ≦ 0.2),

M ^II FX described in JP-A-55-160078
· XA: yLn (However, M ^II is Ba, Ca, Sr, Mg, Zn and Cd
A is BeO, MgO, CaO, SrO, Ba
O, ZnO, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ , SiO ₂ , TiO ₂ , ZrO
₂ , GeO ₂ , SnO ₂ , Nb ₂ O ₅ , at least one of Ta ₂ O ₅ and ThO ₂ , Ln is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd, Y
X is Cl, B at least one of b, Er, Sm and Gd
at least one of r and I, wherein x and y are respectively 5 × 10 ⁻⁵ ≦ x ≦ 0.5 and 0 <y ≦ 0.2)
A phosphor represented by the composition formula:

As described in JP-A-56-116777 (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,
At least one of 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
Is a phosphor represented by the composition formula:

It is described in JP-A-57-23673 (B
a_1-X, M^II _X) F_Two・ ABaX_Two: yEu, zB (where M ^IIIs Belliriu
, Magnesium, calcium, strontium, zinc
And at least one of cadmium and X is chlorine,
At least one of bromine and iodine, a,
x, y, and z are respectively 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦
1, 10^-6≦ y ≦ 2 × 10^-1, And 0 <z ≦ 10^-2Is)
A phosphor represented by the composition formula:

It is described in JP-A-57-23675 (B
a _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,
A is at least one of bromine and iodine, 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 ).

M ^III O described in JP-A-58-69281
X: xCe (where M ^III is Pr, Nd, Pm, Sm, Eu, Tb, Dy, H
at least one trivalent metal selected from the group consisting of o, Er, Tm, Yb and Bi, X is one or both of Cl and Br, and x is 0 <x <0.1
Is a phosphor represented by the composition formula:

Ba _1-X described in JP-A-58-206678
M _{X / 2} L _{X / 2} FX: yEu ²⁺ (where M represents at least one alkali metal selected from the group consisting of Li, Na, K, Rb and Cs; L represents Sc, Y, La, Ce, Pr, Nd, Pm, S
represents at least one trivalent metal selected from the group consisting of m, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Al, Ga, In and Tl; X is Cl, Br and I Represents at least one halogen selected from the group; and x is 10
^-2 ≦ x ≦ 0.5, and y is 0 <y ≦ 0.1).

BaFX.xA: yEu ²⁺ described in JP-A-59-27980
(Where 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) phosphor represented by the composition formula:

BaFX · x described in JP-A-59-47289
A: yEu ²⁺ (where X is at least one halogen selected from the group consisting of Cl, Br and I; A is monovalent or hexafluorosilicic acid, hexafluorotitanic acid and hexafluorozirconic acid) X is a calcined product of at least one compound selected from the group of hexafluoro compounds consisting of salts of divalent metals; and x is 10 ⁻⁶ ≦ x
≦ 0.1, y is 0 <y ≦ 0.1) phosphor represented by the composition formula:

BaFX · x described in JP-A-59-56479
NaX ′: aEu ²⁺ (where X and X ′ are Cl, B
r and at least one of I, wherein x and a are respectively 0 <x ≦ 2 and 0 <a ≦ 0.2)
A phosphor represented by the composition formula:

M ^II FX described in JP-A-59-56480
XNaX ': 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 each selected from Cl, Br and I A is at least one halogen selected from the group consisting of; A is at least one transition 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:

M ^II FX described in JP-A-59-75200
・ AM ^I X ′ ・ bM ′ ^II X ″ ₂・ cM ^III X ₃・ xA: yEu ²⁺ (However, 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 Li, Na, K, Rb and Cs; ^II is at least one divalent metal selected from the group consisting of Be and Mg; M ^III is Al, Ga, In
Is at least one trivalent metal selected from the group consisting of and Tl; A is a metal oxide; X is Cl, Br and I
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 ≦ 10 ⁻² , c is 0 ≦ c ≦
10 ⁻² and a + b + c ≧ 10 ⁻⁶ ; x is 0 <x ≦ 0.5, y
Is 0 <y ≦ 0.2), a phosphor represented by a composition formula:

M ^II X described in JP-A-60-84381
₂ · aM ^II 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 composed of Cl, Br and I At least one halogen selected from the group and X ≠
X '; and a is 0.1≤a≤10.0, x is 0 <x≤0.
2, a stimulable phosphor represented by the composition formula:

M ^II FX described in JP-A-60-101173
AM ^I X ': xEu ²⁺ (where M ^{II is} at least one kind of alkaline earth metal selected from the group consisting ^of Ba, Sr and Ca; M ^I is at least one kind 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 at least one halogen selected from the group consisting of F, Cl, Br and I; a and x are respectively 0 ≦ a ≦ 4.0 and 0 <x ≦ 0.2), a stimulable phosphor represented by a composition formula:

M ^I X: x described in JP-A-62-25189
Bi (however, 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 0 <x A photostimulable phosphor represented by a composition formula of

LnOX: xCe described in JP-A-2-229882 (where Ln is at least one of La, Y, Gd and Lu;
X is at least one of Cl, Br and I, and x is 0 <x
≦ 0.2, and the ratio between Ln and X is 0.500 <X / Ln ≦
0.998, and the maximum wavelength λ of the stimulable excitation spectrum
Cerium-activated rare earth oxyhalide phosphor represented by 550 nm <λ <700 nm).

[0044] Further, the JP 60-84381 No. M ^II X ₂ · aM ^II X described in the _'2: xEu ²⁺ stimulable phosphor, additives such as shown below M ^II X ₂ · aM ^II X ′ ₂ may be contained in the following ratio per 1 mol.

BM described in JP-A-60-166379
^IX "(M^IIs selected from the group consisting of Rb and Cs
X "is at least one alkali metal, and X" is F, Cl, B
at least one member selected from the group consisting of r and I
And b is 0 <b ≦ 10.0);
BKX ″ and cMgX described in Sho 60-221483_Two・ DM
^IIIX ′_Three(However, M^IIIIs Sc, Y, La, Gd and Lu
At least one trivalent metal selected from the group consisting of
X ”, X and X ′ are all F, Cl, Br and I
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^-Five≤b + c
+ d); yB described in JP-A-60-228592
(However, y is 2 × 10^-Four≦ y ≦ 2 × 10^-1JP-A-60
Described in -228593 (where A is SiO _TwoAnd
And P_TwoO_FiveAt least one oxide selected from the group consisting of
And b is 10^-Four≦ b ≦ 2 × 10^-1);
BSiO described in No. 61-120883 (where b is 0 <b
≦ 3 × 10^-2Is described in JP-A-61-120885.
BSnX ″_Two(However, X ″ is composed of F, Cl, Br and I.
At least one halogen selected from the group consisting of
And b is 0 <b ≦ 10^-3Described in JP-A-61-235486.
BCsX ″ and cSnX listed_Two(However, X ″ and X are
A small number selected from the group consisting of F, Cl, Br and I, respectively.
At least a kind of halogen, and b and c are
0 <b ≦ 10.0 and 10 respectively^-6≦ c ≦ 2 × 10^-2In
BCs described in JP-A-61-235487
X ″ ・ yLn³⁺(However, X ″ consists of F, Cl, Br and I
Ln is at least one halogen selected from the group
Sc, Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb
At least one rare earth selected from the group consisting of
And b and y are each 0 <b ≦
10.0 and 10 ^-6≦ y ≦ 1.8 × 10^-1Is).

Among the above-described stimulable phosphors, a divalent europium-activated alkaline earth metal halide-based phosphor and a cerium-activated rare earth oxyhalide 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-described phosphors, and any phosphor can be used as long as it exhibits stimulable emission when irradiated with radiation and then irradiated with excitation light. There may be.

Further, the radiation-emitting panel of the present invention is
Transmissive radiation with visible light and
And / or panels for converting to ultraviolet radiation, for example
The phosphor used for radiographic intensifying screens
As a tungstate-based phosphor (CaWO_Four, MgW
O_Four, CaWO_Four: Pb), terbium activated rare earth oxysulfide
Phosphor (Y_TwoO_TwoS: Tb, Gd_TwoO_TwoS: Tb, La_TwoO_TwoS: Tb, (Y, Gd)_TwoO
_TwoS: Tb, (Y, Gd) O_TwoS: Tb, Tm etc.), Terbium activated rare earth
Phosphate phosphors (YPO_Four: Tb, GdPO_Four: Tb, LaPO_Four: Tb
Terbium-activated rare earth oxyhalide-based fireflies
Optical body (LaOBr: Tb, LaOBr: Tb, Tm, LaOCl: Tb, LaOCl: Tb, T
m, LaOCl: Tb, Tm, LaOBr: Tb, GdOBr: Tb, GdOCl: Tb
Thulium-activated rare earth oxyhalide phosphor
(LaOBr: Tm, LaOCl: Tm, etc.), barium sulfate phosphor
(BaSO_Four: Pb 、 BaSO_Four:EU²⁺, (Ba, Sr) SO_Four:EU²⁺Such),
Bivalent europium activated alkaline earth metal phosphate
Light body (Ba_Three(PO_Four)_Two:EU²⁺, Ba_Three(PO_Four)_Two:EU²⁺Etc.)
Europium activated alkaline earth metal fluoride halides
Phosphor (BaFCl: EU²⁺, BaFBr: Eu²⁺, BaFCl: EU²⁺, Tb, Ba
FBr: Eu²⁺, Tb, BaF_Two・ BaCl_Two・ KCl: Eu²⁺, (Ba ・ Mg) F_Two・ BaCl
_Two・ KCl: Eu ²⁺Etc.), iodide-based phosphors (CsI: Na, CsI: T
l, NaI, KI: Tl, etc.), sulfide-based phosphors (ZnS: Ag, (Zn, C
d) S: Ag, (Zn, Cd) S: Cu, (Zn, Cd) S: Cu, Al, etc.), phosphoric acid
Hafnium-based phosphor (HfP_TwoO₇: Cu etc.), tantalate
Based phosphor (YTaO_Four, YTaO_Four: Tm, YTaO_Four: Nb 、 (Y, Sr) TaO
_4-x: Nb, LuTaO_Four, LuTaO_Four: Nb 、 (Lu, Sr) TaO_4-x: Nb, Gd
TaO_Four: Tm, Gd_TwoO_Three・ Ta_TwoO_Five・ B_TwoO_Three: Tb)
Can be However, the phosphor used in the present invention is
It is not limited to these, but can be
Use any phosphor that emits light in the visible or near ultraviolet region.
Can be

The stimulable phosphor layer of the radiation image storage panel of the present invention is not only composed of a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state, but also containing no binder. It may be composed of only a stimulable phosphor aggregate or a phosphor layer in which a polymer substance is impregnated in a gap between the stimulable phosphor aggregates. Here, a method for producing the radiation image storage panel of the present invention will be described by taking as an example a case where the phosphor layer is composed of a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state.

The phosphor layer can be formed on a support by the following known method. First, a stimulable phosphor and a binder are added to a solvent and mixed well to prepare a coating solution in which the stimulable phosphor is uniformly dispersed in a binder solution. The mixing ratio between the binder and the stimulable phosphor in the coating solution varies depending on the characteristics of the intended radiation image conversion panel, the type of the phosphor, and the like. Generally, the mixing ratio between the binder and the phosphor is 1 : 1 to 1: 100 (weight ratio)
It is more preferable to select from the range of 1: 8 to 1:40 (weight ratio).

The coating solution containing the phosphor and the binder prepared as described above is then uniformly applied to the surface of the support to form a coating film. This application operation
It can be performed by using a usual coating means, for example, a doctor blade, a roll coater, a knife coater, or the like.

The support can be arbitrarily selected from materials known as supports for conventional radiation image conversion panels. Further, in order to strengthen the bond between the support and the phosphor layer or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel, the surface of the support on which the phosphor layer is provided is provided. Applying a polymer substance such as gelatin to provide an adhesion-imparting layer, or providing a light-reflective layer composed of a light-reflective substance such as titanium dioxide or a light-absorbing layer composed of a light-absorbing substance such as carbon black. However, the support used in the present invention may be provided with these various layers. These configurations can be arbitrarily selected according to the purpose, use, and the like of a desired radiation image conversion panel.

Further, as described in JP-A-58-200200, for the purpose of improving the sharpness of the obtained image,
The surface of the support on the side of the phosphor layer (when the surface of the support on the side of the phosphor layer is provided with an adhesiveness-imparting layer, a light-reflecting layer or a light-absorbing layer, means the surface) Irregularities may be formed.

After forming a coating on the support as described above, the coating is dried to complete the formation of the stimulable phosphor layer on the support. The thickness of the phosphor layer depends on the characteristics of the intended radiation image conversion panel, the type of phosphor, the mixing ratio between the binder and the phosphor, and is generally about 20 μm to 1 mm. It is more preferable that the thickness be 50 μm to 500 μm.

The stimulable phosphor layer does not necessarily need to be formed by directly applying a coating solution on the support as described above. For example, a glass plate, a metal plate, a plastic sheet, etc. may be separately provided. After forming a phosphor layer by applying a coating solution on the sheet and drying, the support is pressed against the support or an adhesive is used to separate the support and the phosphor layer. You may join.

The protective film of the present invention comprises a film-forming resin, a reactive silicone reacting with the film-forming resin, and two kinds of white powders having different average particle sizes.
Further, a crosslinking agent, a hardening agent, an anti-yellowing agent and the like may be contained.

Examples of the film-forming resin include known resins for forming a protective film, such as polyurethane resin, polyacrylic resin, cellulose derivative, polymethyl methacrylate, polyester resin, and epoxy resin. It is more preferable to use an organic solvent-soluble fluorine-based resin in order to further increase the water content.

The fluorine-based resin is a polymer of a fluorine-containing olefin (fluoroolefin) or a copolymer containing a fluorine-containing olefin as a copolymer component. Examples thereof include polytetrafluoroethylene, polychlorotrifluoroethylene, and polyfluoroethylene. Examples include vinyl chloride, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, and fluoroolefin-vinyl ether copolymer.

Fluorine-based resins are generally insoluble in organic solvents, but copolymers containing fluoroolefins as copolymer components may be soluble in organic solvents depending on other structural units (other than fluoroolefins) to be copolymerized. Therefore, a solution prepared by dissolving the resin in an appropriate solvent is applied to the phosphor layer and dried to easily form the protective film. An example of such a copolymer is a fluoroolefin-vinyl ether copolymer. In addition, polytetrafluoroethylene and its modified product are also soluble in a suitable fluorinated organic solvent such as a perfluoro solvent, and therefore, like the copolymer containing the above-mentioned fluoroolefin as a copolymer component, the coating is performed. Thus, a protective film can be formed.

As the fluororesins soluble in these organic solvents, there may be used Opstar JN7212, JN7205, JN722 manufactured by JSR Corporation.
0, Daikin Industries, Ltd .: Zeffle LC-930, GK510, Sumitomo 3M, Ltd .: Dionin THV220, Asahi Glass Co., Ltd .: Lumiflon LF100, LF200, LF216T, LF400, LF600, LF810, LF9
16, LF924, LF946, LF976, LF9010 and the like are preferred.

When a fluorine-based resin is used, it is preferable that the resin is crosslinked, since the strength of the resin increases and the reactive silicone reacts with the crosslinking agent to increase the durability as a protective film. It is also possible to crosslink with radiation using a radiation-curable fluororesin.

The reactive silicone (silicone macromonomer) to be contained in the protective film has at least one functional group capable of reacting with polyisocyanate or amino resin or one or more functional groups curable by radiation at both ends or one end. It is preferable to have one. By using such a reactive silicone, the molecular bond between the film-forming resin and the reactive silicone can be further strengthened, so that transport durability and scratch resistance can be further improved. .

The number average molecular weight of the reactive silicone is 5,000 to 2 to further improve the antifouling effect and to further suppress the deterioration of the quality of image information related to the radiation image.
It is preferably in the range of 0000, more preferably in the range of 10,000 to 15,000.

When the above-mentioned film-forming resin has a hydroxyl group or an amino group, the reactive silicone preferably has one or more hydroxyl groups or amino groups at its terminals, and has a hydroxyl group or an amino group at both terminals. At least one
It is preferable to have one or more or two or more at one end,
Those having two or more hydroxyl groups or amino groups at one end are more preferable, and silicones having two or more hydroxyl groups at one end are more preferable. The film-forming resin and the reactive silicone are desirably cross-linked with a polyisocyanate or an amino resin.

When the film-forming resin comprises at least one of a UV- or electron-beam-curable resin, a UV- or electron-beam-curable oligomer, and a UV- or electron-beam-curable monomer, the reactive silicone Preferably have at least one vinyl group at its terminal.
In this case, it is desirable that the film-forming resin and the reactive silicone be cured by irradiation with ultraviolet rays or electron beams.

These reactive silicones are commercially available from Chisso Corporation under the trade name: Syraprene Series, and may be used. Specifically, the following reactive silicones can be used. Note that n in the chemical formula represents a number such that Mn becomes 5,000 to 20,000.

[0066] FM-04 series

Embedded image FM-0421 (Mn = 5,000), FM-0425 (Mn = 10,000) FM-44 series

Embedded image FM-4421 (Mn = 5,000), FM-4425 (Mn = 10,000) FM-33 series

Embedded image FM-3321 (Mn = 5,000), FM-3325 (Mn = 10,000) FM-DA series

Embedded image FM-DA21 (Mn = 5,000), FMDA-25 (Mn = 10,000), FM-DA26 (Mn =
15,000) When using a radiation cross-linkable resin, the FM-07 series represented by the following chemical formula (for example, FM-0721, FM-
[0725] It is preferable to use a reactive silicone having at least one methacryloxy group at at least one terminal as in the above (7725). Here, m in the chemical formula represents a number such that Mn becomes 5,000 to 20,000.

[0067] FM-07 series

Embedded image The reactive silicone is contained in an amount of 0.1 to 20% by weight based on the film-forming resin in order to further improve the antifouling effect and to suppress a decrease in the quality of image information related to a radiation image. And more preferably 0.5 to 10% by weight.

The protective film of the present invention contains two types of white powders having different average particle sizes. The white powder may be an organic white powder or an inorganic white powder, and the two types of white powder may both be an organic white powder or an inorganic white powder. However, one may be an organic white powder and the other may be an inorganic white powder.

The particle shape of the white powder is preferably a substantially spherical or nearly spherical polyhedron (decahedral or more). Further, the distribution of the average particle size is preferably as small as possible, and more preferably monodisperse.
The average particle size of the two types of white powders is both 0.3 μm or more, and preferably 1.5 times or less the protective film thickness, and the protective film thickness is preferably 0.7 to 10 μm, More preferably, it is in the range of 1 to 5 μm.

It is preferable that the difference between the two types of white powder has an average particle size of 0.5 μm or more, or that the larger average particle size is 1.5 times or more the smaller average particle size. Specifically, the average particle size of the smaller one is 0.4 to 0.8 μm, and the average particle size of the larger one is 1 to
It is preferably 2.5 μm. The weight ratio of the two types of white powder (smaller average particle size: larger average particle size) is preferably 10:90 to 95: 5, and 50:50.
More preferably, it is 50 to 90:10.

The amount of addition of these white powders is preferably 1 to 120% by weight based on the film-forming resin of the protective film.
More preferably, it is 5 to 100% by weight. In particular, 5 to 40% by weight of organic white powder and 1 for inorganic white powder.
It is preferably contained in the range of 0 to 100% by weight. When the addition amount of the white powder is small, rainbow unevenness which looks like rainbow tends to occur due to a change in light interference due to thickness unevenness of the protective layer, or sufficient durability cannot be obtained. When the rainbow unevenness becomes remarkable, this is reflected in an image, which is one of the causes of a decrease in image quality. On the other hand, when the amount of the white powder added is large, the laser light for reading the recorded image is diffused, and the resolution is lowered, and the light emission amount is apt to be lowered, which is not preferable.

As the organic white powder, a crosslinked MMA resin,
Cross-linked MMA copolymer, cross-linked styrene resin, cross-linked styrene copolymer, cross-linked silicone resin, phenol resin, melamine resin, benzoguanamine resin, and the like. Specific examples are Soken Chemical Co., Ltd .: MP series, MP-1000, MP- 1100, MP14
01, MP-1600, MR series, MR-2G, Toshiba Silicone Co., Ltd .: Tospearl XC99-A8808, Tospar 120, JSR Co., Ltd .: SX series, Nippon Shokubai Co., Ltd .: Eposter S6, S12, MS And the like can be preferably used.

As the inorganic white powder, silica, alumina,
Examples include yttrium oxide, zinc oxide, calcium carbonate, and barium sulfate. Specific examples are Nippon Shokubai Co., Ltd .: Seahoster KE series P50, P100, P150, Sumitomo Chemical
AKP series, AKP15, 20, 30, 50, HIT10
0, AA05, AA07, AA1, AA1 of Sumicorundum series.
5, AA2, AA3 and the like.

The crosslinking agent used in the protective film of the present invention is preferably a polyisocyanate or an amino resin. As the polyisocyanate, it is more preferable to use a non-yellowing type polyisocyanate which does not easily yellow over time.

As the non-yellowing type polyisocyanate, Nippon Polyurethane Co., Ltd .: Coronate HL, Coronate HX, Sumitomo Bayer Urethane Co., Ltd .: Sumidur N75, N3200, H
T, death module N3300, Z4470, E3265, E4280 and the like can be preferably mentioned.

As the amino resin, melamine such as hexamethoxymethylolmelamine and benzoguanamine can be preferably mentioned. Specific examples of these crosslinking agents include Mitsui Cytec Co., Ltd .: Cymel 303 and the like.
0 series, Cymel 200 series, Cymel 700 series, Cymel 1100 series, Mycoat 100 series,
Preferred are Mycoat 500 series and Cymel 1100 series.

The protective film is formed by thoroughly mixing a film-forming resin, reactive silicone, white powder, a cross-linking agent and the like to prepare a coating liquid for the protective film, and using a doctor blade, dip coater, slide coater, extrusion. After coating, drying and curing on a transparent support such as PET using a coating device such as a coater, the adhesive layer is coated on the PE opposite to the protective film.
It is performed by providing on the T surface and laminating on the phosphor surface, or by directly applying, drying and curing on the phosphor layer surface. Of course, this protective film may be formed simultaneously with the formation of the phosphor layer by simultaneous multi-layer coating.

For the purpose of improving the sharpness of the obtained image, at least one of the layers constituting the radiation image conversion panel of the present invention absorbs excitation light,
The stimulated emission light may be colored by a colorant that does not absorb the light (see Japanese Patent Publication No. 54-23400).

[0079]

EXAMPLES Example 1 A radiation image storage panel of the present invention was manufactured as follows. First, as a phosphor layer forming coating solution, phosphor: BaFBr _0.8 I _0.2 : 0.001Eu ²⁺ 1000 g,
246 g of a 13% MEK solution of a polyurethane resin (manufactured by Dainippon Ink and Chemicals, Inc .: Pandex T5265H), bisphenol A type epoxy resin (manufactured by Shell Chemical Co., Ltd .: Epicoat 10)
30 g of a 50% MEK solution of 01), 3 g of a polyisocyanate (manufactured by Nippon Polyurethane Co., Ltd .: Coronate HX), and 0.02 g of ultramarine as a coloring agent (Daiichi Kasei Kogyo Co., Ltd .: SM-1) in 52 g of MEK using a disper. The mixture was dispersed for 3 hours to prepare a coating liquid having a viscosity of 3.5 Pa · s (25 ° C.).

This coating solution was applied on a polyethylene terephthalate sheet (temporary support, thickness: 180 μm) coated with a silicone release agent by an extrusion coater to a dry thickness of 250 μm, dried, and then temporarily supported. Peeled from the body.

Next, a support having an undercoat layer was prepared. 350 g of gadolinium oxide (Gd ₂ O ₃ ) fine particles (90% by weight of all particles having a particle size in the range of 1 to 5 μm),
Soft acrylic resin as a binder (Dainippon Ink and Chemicals
Co., Ltd .: Chris Coat P-1018GS (20% toluene solution)) 1800
g, phthalic acid ester as plasticizer (Daichi Chemical Co., Ltd .: # 1
0) 40g, ZnO whisker as conductive agent (Matsushita Amtech)
Co., Ltd .: 120 g of Panatetra A-1-1) and 2 g of ultramarine as a colorant (Daiichi Kasei Kogyo Co., Ltd .: SM-1) were added to MEK, and dispersed and dissolved using a disper to form an undercoat layer. 0.5P for application liquid
a · s (20 ° C), and adjust this to a PET sheet (Lumirror S-10 250 µm, manufactured by Toray; haze degree (typical) = 20; light shielding layer made of carbon black, silica, binder on one side (about 18 µm)
Was applied uniformly on the side opposite to the light-shielding layer using an extrusion coater, and then the coating was dried and applied. In this way, a layer thickness of 20μ
A support having an undercoat layer was formed.

Subsequently, the phosphor sheet and the support with an undercoat layer were overlaid, and a pressure of 49 MPa was applied using a calender roll.
a, Heat compression was continuously performed at an upper roll temperature of 75 ° C, a lower roll temperature of 75 ° C, and a feed rate of 1.0 m / min. By this heat compression, the phosphor sheet was completely fused to the support via the undercoat layer to form a phosphor layer (layer thickness: 210 μm).

Next, a protective film was formed. 40 g of a fluorine-based copolymer resin solution (Lumiflon LF504X (30% xylene solution) manufactured by Asahi Glass Co., Ltd.) and 30 g of white powder (small particles; Nippon Shokubai Co., Ltd .: melamine resin powder, eposter S6 (average particle size) ≒ 0.6 μm), large particles; Nippon Shokubai Co., Ltd .: Melamine resin powder, Eposter S12 (average particle size ≒ 1.2 μm),
The weight% ratio is small particles: large particles = 10:90), aluminum coupling agent as a dispersant (Ajinomoto Co., Prenact AL-M)
A mixture of 0.5 g and a solvent (MEK) 200 g was dispersed and mixed in a ball mill using zirconia balls of 3 mmφ for 20 hours.
Add 360 g of Lumiflon LF504X (30% xylene solution)
Further dispersed for 4 hours.

Thereafter, 2.8 g of reactive silicone FM-DA26 (Mn @ 15,000, Chisso Corporation) and a crosslinking agent (polyisocyanate; Sumitomo Bayer Urethane Co., Ltd., Sumidur N3300)
(Solid content 100%)) 22.2 g, a catalyst (Kyodo Chemical Co., Ltd .: dibutyltin dilaurate KS1260) 1.4 mg and MEK 800 g were additionally mixed to prepare a coating solution.

The protective film coating solution was applied to the surface of the above-mentioned 9 μm PET film by a bar coater, heat-treated at 120 ° C. for 20 minutes, dried and thermally cured to form a protective film.

Subsequently, a 20 μm thick OPP film (Toray Industries, Inc.)
Co., Ltd., Trefan YM-11 # 20), apply an unsaturated polyester resin solution (Toyobo Co., Ltd .: Byron 30SS) and dry to form an adhesive layer (adhesive application weight 9 g / m ² ). This OPP film was adhered to the opposite side (light-shielding layer side) of the support from the side on which the phosphor layer was provided using an adhesive layer using a laminating roll to form a back protective layer.

Example 2 A radiation image conversion panel was manufactured in the same manner as in Example 1 except that the ratio of the small particles to the large particles of the white powder used in the protective film of Example 1 was changed to 50:50. did.

(Example 3) A radiation image conversion panel was manufactured in the same manner as in Example 1 except that the ratio of the small particles to the large particles of the white powder used in the protective film of Example 1 was 80:20. did.

(Example 4) A radiation image conversion panel was manufactured in the same manner as in Example 1 except that the ratio of the small particles to the large particles of the white powder used in the protective film of Example 1 was 95: 5. did.

(Example 5) A radiation image conversion panel was prepared in the same manner as in Example 3, except that the amount of the white powder added was doubled to 60 g.

Example 6 The same procedure as in Example 3 was repeated except that the large particles used in the protective layer were replaced with alumina powder (Sumitomo Chemical Co., Ltd .: Sumicorundum AA-1 (average particle size ≒ 1.2 μm)). Thus, a radiation image conversion panel was prepared.

(Comparative Example 1) A radiation image conversion panel was manufactured in the same manner as in Example 3, except that only a large white powder was used for the protective film.

Comparative Example 2 A radiation image conversion panel was manufactured in the same manner as in Example 3, except that only a small white powder was used for the protective film.

Comparative Example 3 A radiation image conversion panel was manufactured in the same manner as in Example 3 except that no white powder was used for the protective film.

(Evaluation Experiment) Coefficient of friction The coefficient of friction of each protective film surface of the radiation image storage panels obtained in the examples and comparative examples was measured by the following method. First, the radiation image conversion panel was cut into a rectangle of 5 cm × 15 cm, and placed on a measuring table whose angle was inclined so that the protective film was on the upper surface. Next, a 0.98N load was applied to the EPDM rubber plate cut into 3 cm × 4 cm, placed on the protective film, and the angle δ at which the nonwoven fabric started to move was measured by gradually tilting the measuring table.
The measurement was performed before and after the sliding shown in 4 below. Angle δ
The static friction coefficient (μ value) was calculated from the following equation. μ value = tan δ

2. Pencil antifouling property The surface of the protective layer was traced with a pencil (darkness of B), the appearance of the pencil was visually observed, and the degree of dirt due to fine irregularities on the surface was observed. A: Invisible B: Appears thin C: Appears sharply Magic antifouling

A line was drawn on the surface of the protective film with black magic, dried and wiped dry with a Kimwipe, and the degree of erasure of the magic line was observed. A: No remaining line B: About half remaining C: Full remaining

4. Magic antifouling after sliding Nonwoven fabric cut to 3 cm x 4 cm on the protective film of a radiation image conversion panel cut to a rectangle of 5 cm x 15 cm (Idemitsu Petrochemical Co., Ltd.
(Trade name: Stratec) with a load of 0.98N, and slid back and forth 400,000 times. A line was drawn with black magic on the surface of the protective film after sliding, and dried and wiped with a Kimwipe. The degree of erasure of the magic line was observed before and after sliding, and evaluated on the following three levels. A: No remaining line B: About half remaining C: Full remaining

5. Scratch The scratch resistance of the surface of the protective film after sliding was evaluated on the following three scales. A: Almost no scratches B: Some scratches occurred, but no problem in practical use C: Very large scratches

6. Rainbow unevenness Rainbow unevenness caused by a subtle change in the thickness of the protective layer changing light interference was visually observed and evaluated according to the following three grades. A: None B: Visible but no real harm C: Real harm Table 1 shows the weight (%) ratio of white powder and the evaluation results.

[0101]

[Table 1] From the above experimental results, the protective film surface of the radiation image conversion panel according to the present invention has a low coefficient of friction even after sliding, has antifouling properties, is relatively hard to scratch, and effectively suppresses the occurrence of rainbow unevenness. It is clear that.

Although the embodiment is directed to a radiation image conversion panel, a panel for converting transmitted radiation into visible light and / or ultraviolet radiation using a non-stimulable phosphor, for example, for X-ray photography It is also very useful as a protective film when used repeatedly, such as in an intensifying screen, where contamination or scratches on the panel surface become a problem.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a radiation-emitting panel according to a first embodiment of the present invention.

[Explanation of symbols]

 10 Radiation panel 11 Support layer 12 Phosphor layer 13 Protective film

Claims (8)

[Claims] 1. A radiation-emitting panel having a phosphor layer and a protective film, wherein the protective film is formed of a film-forming resin, a reactive silicone reacting with the film-forming resin, and two kinds of particles having different average particle sizes. Wherein the two types of white powders each have an average particle size of not less than 0.3 μm and not more than 1.5 times the protective film thickness. panel. 2. The radiation-emitting panel according to claim 1, wherein said protective film has a thickness in a range of 0.7 to 10 μm. 3. The radiation-emitting panel according to claim 2, wherein said protective film has a thickness of 1 to 5 μm. 4. The radiation-emitting panel according to claim 1, wherein the larger average particle size of the two types of white powder is 1.5 times or more the smaller average particle size. 5. The method according to claim 1, wherein the smaller average particle size of the two types of white powder is in the range of 0.4 to 0.8 μm, and the larger average particle size is in the range of 1 to 2.5 μm. The radiation emitting panel according to claim 4. 6. The weight ratio between the smaller average particle size and the larger average particle size of the two types of white powder is 1%.
The ratio is from 0:90 to 95: 5.
The radiation-emitting panel according to claim 1. 7. The weight ratio of the smaller average particle size of the two types of white powder to the larger average particle size of the two types of white powder is 5%.
7. The radiation-emitting panel according to claim 6, wherein the ratio is from 0:50 to 90:10. 8. The radiation-emitting panel according to claim 1, wherein the white powder is contained in an amount of 1 to 120% by weight based on the film-forming resin.