JP2769932B2 - Radiation image conversion panel - Google Patents

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.

[0002]

2. Description of the Related Art As an alternative to the conventional radiographic method, there has been 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. By absorbing the stimulable phosphor with electromagnetic waves (excitation light) such as visible light and infrared light in a time series manner, the radiation energy stored in the stimulable phosphor is absorbed by the body. The fluorescent light is emitted (stimulated emission light), the fluorescent light is read photoelectrically to obtain an electric signal, and a radiation image of a subject or a subject is reproduced as a visible image based on the obtained electric signal. . After the reading of the panel is completed, after the remaining image is deleted, the panel is prepared for the next photographing. 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, the radiographic image conversion method uses the radiographic image conversion panel repeatedly, which is advantageous in terms of resource conservation and economic efficiency. It is.

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 the surface of the support. However,
When the phosphor layer is self-supporting, a support is not necessarily required. The stimulable phosphor layer usually comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. However, as the stimulable phosphor layer, a layer composed of only an aggregate of the stimulable phosphor without a binder formed by a vapor deposition method or a sintering method is known. Further, there is known a radiation image conversion panel having a stimulable phosphor layer in which a polymer substance is impregnated in a gap between stimulable phosphor aggregates. In any of these phosphor layers, the stimulable phosphor is X
When irradiated with excitation light after absorbing radiation such as radiation, it has the property of stimulating luminescence, so radiation transmitted through a subject or emitted from a subject is proportional to the amount of radiation. Absorbed by the stimulable phosphor layer of the image conversion panel, a radiation image of the subject or the subject is formed on the panel as an accumulated image of radiation 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 the stimulated emission light and converting it into an electric signal. It is possible to do.

Incidentally, a protective film is usually provided on the surface of the stimulable phosphor layer (the surface not facing the support) so that the phosphor layer is chemically altered or physically impacted. Is protected from. 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.

[0006] Among them, the protective film formed by coating has advantages in that it generally has strong adhesive strength to the phosphor layer and can be manufactured by a relatively simple process.

[0007] In the practice of the radiation image conversion method, the radiation image conversion panel includes radiation irradiation (recording of a radiation image) and irradiation of excitation light (reading of a recorded radiation image).
It is used repeatedly in the cycle of irradiating erasing light (erasing the remaining radiation image). The transition of the radiation image conversion panel to each step is performed by a conveying means such as a belt or a roller. After one cycle, the panels are usually stacked and stored. However, when the radiation image conversion panel having the protective film formed by coating as described above is repeatedly used in this manner, the sensitivity of the panel may gradually decrease. As with the conventional radiographic method, it is desired that the radiation image conversion panel also has high sensitivity and gives an image with good image quality (sharpness, granularity, etc.). Preventing the decline is an important issue.

As a coating film capable of preventing the sensitivity of the radiation image conversion panel from lowering due to the above-mentioned repetition, a coating film which has already been filed by the present applicant includes a phosphor layer composed of a stimulable phosphor and a protective film. In the radiation image conversion panel,
A radiation image conversion panel, wherein the protective film is a film formed of a coating film containing an organic solvent-soluble fluorine-based resin, has been known (JP-A-2-193100).

[0009]

A radiation image storage panel having a protective film formed of a coating film containing an organic solvent-soluble fluorine-based resin as described above can be used as a radiation image conversion panel even when repeatedly used under normal conditions. It was found to be excellent with little decrease in sensitivity, but it was found that if the surface of the protective film was repeatedly brought into contact with the surface of another object and was rubbed, there was a problem that the surface was easily damaged by friction. If the surface of the protective film is scratched in this way, there is a problem that the image quality of the resulting radiographic image is likely to deteriorate, and that the durability of the radiographic image conversion panel is reduced.

[0010]

According to the present invention, a protective film of a radiation image conversion panel having a phosphor layer composed of a stimulable phosphor and a protective film is formed by a coating film containing an organic solvent-soluble fluororesin. Is formed, and polytetrafluoride is formed in the coating film.
By dispersing and containing the ethylene resin powder, it has become possible to obtain a radiation image conversion panel having excellent sensitivity and high scratch resistance.

Here, the fluorine-based resin refers to a polymer of an olefin containing fluorine (fluoroolefin) or a copolymer containing an olefin containing fluorine as a copolymer component. The film formed by the above-mentioned fluororesin coating film may be crosslinked.

Preferred embodiments of the present invention are listed below. (1) A radiation image conversion panel in which a polytetrafluoroethylene resin powder is contained in the protective film in an amount of 0.5 to 30% by weight based on the weight of the protective film. (2) A radiation image conversion panel wherein the average particle size of the polytetrafluoroethylene resin powder is in the range of 0.1 to 10 μm. (3) The radiation image conversion panel, wherein the fluororesin is at least one fluororesin selected from the group consisting of a copolymer containing a fluoroolefin as a copolymer component, polytetrafluoroethylene, and a modified polytetrafluoroethylene. . (4) A radiation image conversion panel wherein the fluororesin is at least one fluororesin selected from the group consisting of a copolymer of fluoroolefin and vinyl ether, polytetrafluoroethylene and a modified polytetrafluoroethylene. (5) A radiation image conversion panel wherein the fluororesin is at least one fluororesin selected from the group consisting of a copolymer of fluoroolefin and vinyl ether and a modified polytetrafluoroethylene. (6) A radiation image conversion panel wherein the fluororesin is a copolymer of fluoroolefin and vinyl ether. (7) A radiation image conversion panel in which the fluororesin is polytetrafluoroethylene or a modified product thereof. (8) A radiation image conversion panel wherein the fluororesin component in the protective film is 30% by weight or more. (9) A radiation image conversion panel, wherein the fluororesin component in the protective film is 50% by weight or more. (10) 70% by weight of the fluororesin component in the protective film
A radiation image conversion panel characterized by the above. (11) A radiation image conversion panel, wherein the fluorine-based resin in the protective film is cross-linked.

The radiation image conversion panel of the present invention will be described in detail below.

First, the stimulable phosphor constituting the phosphor layer of the radiation image storage panel of the present invention will be described. The stimulable phosphor is a phosphor that emits stimulable light when irradiated with radiation and then with excitation light as described above, but has a wavelength in the range of 400 to 900 nm from a practical viewpoint. It is desirable that the phosphor emits stimulated emission in the wavelength range of 300 to 500 nm by the excitation light. Examples of the stimulable phosphor used in the radiation image conversion panel of the present invention,

SrS: Ce, Sm, SrS: Eu, Sm, ThO described in US Pat. No. 3,859,527.
₂ : Er, and La ₂ O ₂ S: Eu, Sm, ZnS: Cu, P described in JP-A-55-12142.
b, BaO.xAl ₂ O ₃ : Eu (provided that 0.8 ≦ x
≦ 10) and M ^II O · xSiO ₂ : A (where M ^II
Is Mg, Ca, Sr, Zn, Cd or Ba;
Is Ce, Tb, Eu, Tm, Pb, Tl, Bi, or Mn, and x is 0.5 ≦ x ≦ 2.5),

(Ba _{1 -xy} , Mg _x , Ca _y ) FX: aEu ²⁺ described in JP _-A- 55-12143 (where X is at least one of Cl and Br, x and y is 0 <x + y ≦ 0.6 and xy ≠ 0, and a is 10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ),

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

(Ba _1-x , M ²⁺ _x ) FX: yA described in JP-A-55-12145 (where M ²⁺ is M
g, at least one of Ca, Sr, Zn and Cd, X is at least one of Cl, Br and I, A is Eu, Tb, Ce, Tm, Dy, Pr, Ho,
At least one of Nd, Yb, and Er, and x is 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.2),

M ^II FX · xA: yLn described in JP-A-55-160078 [where M ^II is Ba, Ca,
At least one of 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 , SnO
₂ , Nb ₂ O ₅ , Ta ₂ O ₅ , and at least one of ThO ₂ , Ln is Eu, Tb, Ce, Tm, D
y, Pr, Ho, Nd, Yb, Er, Sm, and Gd
X is at least one of Cl, Br, and I, and x and y are each 5
× 10 ⁻⁵ ≦ x ≦ 0.5 and 0 <y ≦ 0.2].

(Ba _{1 -x} , M ^II _x ) F ₂ .aBaX ₂ : yEu, zA described in JP-A-56-116777
[Where 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] , 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 ⁻² ].

(B) described in JP-A-57-23673.
^{_{a 1-x, M II x}} ) F 2 · aBaX 2: yEu, zB [ However, M ^II is beryllium, magnesium, calcium,
At least one of strontium, zinc and cadmium, X is at least one of chlorine, bromine and iodine, 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 ≦ 2 × 10 ^-1 ],

(B) described in JP-A-57-23675
^{_{a 1-x, M II x}} ) F 2 · aBaX 2: yEu, zA [ However, M ^II is beryllium, magnesium, calcium,
X is at least one of chlorine, bromine and iodine, A is at least one of arsenic and silicon, and a, x, y and z are each at least one of strontium, zinc and cadmium. 5 ≦ a
≦ 1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 5 × 10 ⁻¹ ].

M described in JP-A-58-69281
^III OX: xCe [where M ^III is Pr, Nd, P
m, Sm, Eu, Tb, Dy, Ho, Er, Tm, Y
b, and at least one trivalent metal selected from the group consisting of Bi, X is one or both of Cl and Br, and x is 0 <x <0.1]. A phosphor represented by the formula:

B described in JP-A-58-206678
a _1-x M _{x / 2} L _{x / 2} FX: yEu ²⁺ [where M is L
L represents at least one alkali metal selected from the group consisting of i, Na, K, Rb and Cs;
Y, La, Ce, Pr, Nd, Pm, Sm, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu, Al, G
X represents at least one trivalent metal selected from the group consisting of a, In, and Tl; X represents at least one halogen selected from the group consisting of Cl, Br, and I; and x represents 10 ^-2. ≦ x ≦ 0.5, y is 0 <y
≦ 0.1], a phosphor represented by a composition formula:

B described in JP-A-59-27980
aFX · xA: yEu ²⁺ [where X is Cl, Br,
A is at least one halogen selected from the group consisting of and I; A is a calcined product of a tetrafluoroborate compound; and x is 10 ⁻⁶ ≦ x ≦ 0.1, and y is 0 <y
≦ 0.1], a phosphor represented by a composition formula:

B described in JP-A-59-47289
aFX · xA: yEu ²⁺ [where X is Cl, Br,
And A is selected from the group consisting of hexafluorosilicic acid, hexafluorotitanic acid and a salt of a monovalent or divalent metal of hexafluorozirconic acid. X is a calcined product of at least one compound; and x is 10 ⁻⁶ ≦ x ≦ 0.1, and y is 0 <y ≦
0.1], a phosphor represented by a composition formula:

B described in JP-A-59-56479
aFX.xNaX ': aEu ²⁺ [where X and X'
Is at least one of Cl, Br, and I, and x and a are respectively 0 <x ≦ 2 and 0 <a ≦ 0.2].

M described in JP-A-59-56480
^II FX.xNaX ': yEu ²⁺ : zA [where M ^II is
X and X 'are at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca;
A is at least one halogen selected from the group consisting of Cl, Br and I; A is V, Cr, M
x is at least one transition metal selected from n, Fe, Co, and Ni; and x is 0 <x ≦ 2, and y is 0
<Y ≦ 0.2 and z is 0 <z ≦ 10 ⁻² ], a phosphor represented by a composition formula:

M ^II described in JP-A-59-75200
FX ・ aM ^I X ′ ・ bM ′ ^II X ″ ₂・ cM ^III X ″ ′ ₃・
xA: yEu ²⁺ [where M ^II is Ba, Sr, and C
is at least one alkaline earth metal selected from the group consisting of a; M ^I is Li, Na, K, Rb, and C
M ′ ^II is at least one divalent metal selected from the group consisting of Be and Mg; M ^III is Al,
X is at least one trivalent metal selected from the group consisting of Ga, In, and Tl; A is a metal oxide;
Is at least one halogen selected from the group consisting of Cl, Br, and I; X ′, X ″ and X ″ ″ are
Is 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 described in JP-A-60-84381
X ₂ · aM ^II X ′ ₂ : xEu ²⁺ [where M ^II is Ba,
At least one alkaline earth metal selected from the group consisting of Sr and Ca; X and X 'are Cl, Br
At least one halogen selected from the group consisting of and I, and X ≠ X ′; and a is 0.1 ≦ a ≦
10.0, x is 0 <x ≦ 0.2], a stimulable phosphor represented by a composition formula:

M described in JP-A-60-101173
^{II FX · aM I X ':} xEu 2+ [ However, M ^II is Ba,
M ^I is at least one alkali metal selected from the group consisting of Rb and Cs; M is at least one alkaline earth metal selected from the group consisting of Sr and Ca; X is from the group consisting of Cl, Br and I X 'is at least one halogen selected; X' is F, Cl, Br
And at least one halogen selected from the group consisting of I and I; and a and x are each 0 ≦ a ≦
4.0 and 0 <x ≦ 0.2], a stimulable phosphor represented by a composition formula:

M described in JP-A-62-25189
^I X: xBi [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 ≦ 0.2
A stimulable phosphor represented by the composition formula:

L described in JP-A-2-229882
nOX: xCe (where Ln is at least one of La, Y, Gd and Lu, X is Cl, Br and I
At least one of x is 0 <x ≦ 0.2,
The ratio of Ln to X is 0.500 <X / Ln ≦
And cerium-activated rare earth oxyhalide phosphors having a maximum wavelength λ of 0.998 and a stimulable excitation spectrum having a maximum wavelength λ of 550 nm <λ <700 nm.

The M ^II X ₂ · aM ^II X ′ ₂ : xEu ²⁺ stimulable phosphor described in JP-A-60-84381 described above contains the following additives M ^II X ₂・ aM
^II X ′ ₂ may be contained in the following ratio per 1 mol.
BM ^I X described in JP 60-166379 discloses "
(Where M ^I is at least one alkali metal selected from the group consisting of Rb and Cs, and X ″ is F, C
at least one halogen selected from the group consisting of l, Br and I, and b is 0 <b ≦ 10.0); bK described in JP-A-60-221483
_{X "· cMgX"'2 ·} dM III X "" 3 ( where, M ^III
Is at least one trivalent metal selected from the group consisting of Sc, Y, La, Gd and Lu, and X ″, X ″ ′ and X ″ ″ are each selected from the group consisting of F, Cl, Br and I At least one halogen, and b,
c and d are respectively 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 (provided that y is 2 × 10 ⁻⁴ ≦ y ≦ 2 × 10 ⁻¹ ); and yB described in JP-A-60-228593. bA
(Where A is at least one oxide selected from the group consisting of SiO ₂ and P ₂ O ₅ , and b is 1
0 at ^-4 ≦ b ≦ 2 × 10 ^-1 is); JP 61-1208
No. 83, where b is 0 <b ≦ 3
× 10 ^-2 ); bSnX ″ ₂ described in JP-A-61-120885, wherein X ″ is at least one halogen selected from the group consisting of F, Cl, Br and I; Is 0 <b ≦ 10 ⁻³ ); bCsX ″ · cSn described in JP-A-61-235486.
X "' ₂ (where X" and X "' are each F, Cl,
At least one halogen selected from the group consisting of Br and I, and b and c are each 0 <
b ≦ 10.0 and 10 ⁻⁶ ≦ c ≦ 2 × 10 ⁻² );
And bCsX ".yLn3 ⁺ (where X" is F, Cl, B
rn is at least one halogen selected from the group consisting of r and I, and Ln is Sc, Y, Ce, Pr, Nd, S
m, 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 ≦ 1.
0.0 and 10 ⁻⁶ ≦ y ≦ 1.8 × 10 ⁻¹ ).

Of 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.

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 the stimulable phosphor in a dispersed state but also containing no stimulable phosphor. 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.

Next, the method for producing the radiation image storage panel of the present invention will be described by taking, as an example, the case where the phosphor layer comprises 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%. It is selected from the range of 1: 1 to 1: 100 (weight ratio), and particularly preferably selected 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 coating operation can be performed by using ordinary 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. In a known radiation image conversion panel, a phosphor layer is provided to enhance the bond between the support and the phosphor layer or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymer material such as gelatin is applied to the surface of the support on the side to form an adhesion-imparting layer, or a light-reflective layer made of a light-reflective material such as titanium dioxide, or a light-absorbent material such as carbon black It is known to provide an absorption layer or the like. The support used in the present invention can also be provided with these various layers, and the configuration thereof can be arbitrarily selected depending on the desired purpose and application of the radiation image storage panel. Further, JP-A-58-20020
As described in JP-A No. 0, the surface of the support on the side of the phosphor layer (the surface of the support on the side of the phosphor layer, the adhesion-imparting layer, In the case where a layer or a light absorbing layer is provided, the surface thereof means fine irregularities. 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 varies depending on the desired characteristics of the radiation image conversion panel, the type of phosphor, the mixing ratio of the binder and the phosphor, and the like, but is usually 20 μm to 1 mm. However, this layer thickness is preferably 50 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 separate sheet such as a glass plate, a metal plate, or a plastic sheet may be used. After the phosphor layer is formed by applying a coating solution on the substrate and drying, the phosphor layer is pressed onto the support, or the support and the phosphor layer are joined by using an adhesive or the like. Is also good.

Next, a description will be given of a protective film formed of a coating film of a fluorine-based resin soluble in an organic solvent, which is a characteristic requirement of the radiation image conversion panel of the present invention, in which polytetrafluoroethylene resin powder is dispersed and contained. .

The protective film of the radiation image storage panel of the present invention is
Film-forming resin and port containing fluoroplastics soluble in organic solvents
A coating solution of a protective film forming material composed of a powder of lithium tetrafluoroethylene resin is uniformly applied to the surface of the phosphor layer using an application means such as a doctor blade, and dried to form a coating. Of course, this protective film may be formed simultaneously with the formation of the phosphor layer by simultaneous multi-layer coating.

The fluororesin is a polymer of a fluorine-containing olefin (fluoroolefin) or a copolymer containing a fluorine-containing olefin as a copolymer component. 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 the 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, whereby a protective film can be easily formed. Examples of such a copolymer include 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.

The protective film of the radiation image storage panel of the present invention may contain a resin other than a fluorine resin, or may contain a crosslinking agent, a hardening agent, a yellowing inhibitor and the like as described below. May be. However, in order to sufficiently achieve the above object, the content of the fluororesin in the protective film is suitably at least 30% by weight, preferably at least 50% by weight, and more preferably at least 70% by weight. It is preferable that it is above. Examples of the resin other than the fluorine-based resin contained in the protective film of the radiation image storage panel of the present invention include a polyurethane resin, a polyacryl resin, a cellulose derivative, polymethyl methacrylate, a polyester resin, and an epoxy resin. Further, since the strength of the resin increases and the durability as a protective film increases, it is preferable that the fluororesin used in the present invention is crosslinked. Therefore, the above-mentioned protective film forming material coating liquid includes:
A resin other than the fluorine-based resin, a crosslinking agent, and the like may be contained, and further, a yellowing inhibitor and the like may be contained.

In the present invention, the protective film is dispersed and contained.
The polytetrafluoroethylene resin powder preferably has an average particle size in the range of 0.1 to 10 μm, and particularly preferably has an average particle size in the range of 0.3 to 5 μm. The polytetrafluoroethylene resin powder is preferably contained in the protective film in an amount of 0.5 to 30% by weight based on the weight of the protective film, particularly in an amount of 2 to 20% by weight, and more preferably 5 to 15% by weight. It is preferably contained in an amount of% by weight.

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).

[0047]

【Example】

Example 1 A radiation image storage panel of the present invention was manufactured as follows.

As a phosphor layer forming material, a phosphor: BaFBr
_0.8 I _0.2 : 0.001 Eu ²⁺ 600 g, polyurethane resin (Desmolac 4125 manufactured by Sumitomo Bayer Urethane Co., Ltd.) 15.8
g, bisphenol A type epoxy resin 2.0 g was added to a mixed solvent of methyl ethyl ketone-toluene (1: 1),
Dispersed by propeller mixer, viscosity 25-30PS
Was prepared. This coating solution was applied on an undercoated polyethylene terephthalate film using a doctor blade, and then dried at 100 ° C. for 15 minutes to form a phosphor layer.

Next, 70 g of a fluororesin: fluoroolefin-vinyl ether copolymer (Lumiflon LF100 manufactured by Asahi Glass Co., Ltd.) and a cross-linking agent: isocyanate (Desmodur Z4370 manufactured by Sumitomo Bayer Urethane Co., Ltd.) were used as protective film forming materials. 25 g, bisphenol A epoxy resin 5
g and 10 g of silicone resin fine powder (KMP-590, manufactured by Shin-Etsu Chemical Co., Ltd., particle size: 1-2 μm) were added to a mixed solvent of toluene-isopropyl alcohol (1: 1) to prepare a coating solution. This coating solution is applied onto the phosphor layer formed in advance as described above using a doctor blade, and then heat-treated at 120 ° C. for 30 minutes to be heat-cured and dried. A membrane was provided.

Example 2 In Example 1, a polytetrafluoroethylene resin fine powder (Lubron L-2, manufactured by Daikin Co., Ltd., having a primary particle size of 0.1) was used in place of the silicone resin.
3 μm, secondary particle diameter 5 μm), except that the same operation was performed to produce a radiation image conversion panel according to the present invention.

Comparative Example 1 The same operation as in Example 1 was carried out except that no silicone resin was used, to produce a radiation image conversion panel belonging to the known art.

Comparative Example 2 In Example 1, the protective layer was made of a fluoroolefin-vinyl ether copolymer (fluororesin: Lumiflon LF504X manufactured by Asahi Glass Co., Ltd.).
0 g and isocyanate (crosslinking agent: Olester NP-38-70S manufactured by Mitsui Toatsu Chemicals, 70% by weight ethyl acetate solution))
The same operation was performed except that 9 g was dissolved in methyl ethyl ketone to obtain a radiation image conversion panel belonging to a known technique.

[Evaluation Experiment] Coefficient of friction The coefficient of friction of the protective film surface of each of the radiation image storage panels obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was measured by the following method. First, the radiation image conversion panel is 2cmx2
The sample was cut into a square of cm to prepare a measurement sample. Next, on a polyethylene terephthalate sheet prepared separately,
The measurement sample was placed with the protective layer side down, and a load was applied on the sample so as to be 100 g including the weight of the sample. Next, the sample to which the load is applied is pulled along the sheet at a tensile speed of 4 cm / min, and Tensilon (UTM-11-20: manufactured by Toyo Baldwin Co., Ltd.)
At a temperature of 25 ° C. and a humidity of 60% at a speed of 4 c.
The tensile force F (g) of the sample in the m / min motion state was measured. From this tensile force F and the above-mentioned load (100 g), the coefficient of friction of the protective layer surface of the radiation image conversion panel sample was calculated by the value of tensile force / load. Table 1 shows the results.

2. Scratch resistance The scratch resistance of the protective film surface of each of the radiation image conversion panels obtained in Examples 1 and 2 and Comparative Examples 1 and 2 was measured by the following method. 25.2cmx3 radiation image conversion panel
The sample was cut into a rectangle of 0.3 cm to prepare a measurement sample. Next, a polyethylene terephthalate base sheet made of the same material as that used as the support of the radiation image storage panel was prepared, and the measurement sample was placed on this sheet with the protective layer side down. In this state, the sample was repeatedly reciprocated 1000 times with a stroke of 10 cm, and the support and the base sheet were rubbed. Then, the surface of the protective layer of the sample was visually observed and evaluated. The evaluation was performed based on the following three levels. A: Almost no scratches occurred. B: Scratches were slightly generated, but no problem in practical use. C: The occurrence of scratches is extremely large.

Table 1 Sample Friction coefficient Scratch resistance Example 1 0.48 A Example 2 0.50 A Comparative Example 1 0.80 C Comparative Example 2 0.85 C

From the above experimental results, it is clear that the protective layer surface of the radiation image storage panel according to the present invention has a low coefficient of friction and high flaw resistance.

Claims (1)

(57) [Claims] 1. A radiation image conversion panel having a phosphor layer comprising a stimulable phosphor and a protective film, wherein the protective film is a film formed by a coating film containing a fluorine-based resin soluble in an organic solvent. And polytetrafur in the coating film.
A radiation image conversion panel, characterized by dispersing an ethylene resin powder.