JP2000241597A - Radiation image conversion panel and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image conversion panel that is excellent in the suitability for the compressing and fusing treatment of a substrate and a phosphor layer, has strong adhesivity between them and is highly durable- cracks hardly appear even if the panel is used repeatedly--and a method for manufacturing the panel. SOLUTION: This radiation image conversion panel is characterized by the fact that it has at least a substrate and a phosphor layer containing a bonding agent and stimulable phosphors on a support in order of mention and the feature that the substrate contains a non-crosslinkable organic compound, whose molecular weight is 900 or less, of 12 to 35 wt.% to the weight of its total solids. Some of preferable conditions are as follows: The phosphor layer is bonded onto the substrate by heating compression, a non-crosslinkable organic compound contains a plasticizer and the non-crosslinkable organic compound contains the one or more selected among fatty ester, phthalic ester and phosphoric ester.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor and a method of manufacturing the same.

[0002]

2. Description of the Related Art 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 is known. This method utilizes a radiation image conversion panel (sometimes referred to as a stimulable phosphor sheet) containing a stimulable phosphor, and transmits radiation transmitted through a subject or emitted from a subject to the panel. The stimulable phosphor is absorbed in the stimulable phosphor, and then the stimulable phosphor is excited by electromagnetic waves (excitation light) such as visible light and infrared light in a time-series manner, whereby the stimulable phosphor is accumulated in the stimulable phosphor. The emitted radiation energy is emitted as fluorescence (stimulated emission light), the fluorescence 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. Things.

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. Therefore, this method is very useful especially in direct medical radiography at the time of X-ray radiography for medical diagnosis.

The radiation image conversion panel used in the radiation image conversion method has, as a basic structure, a support, an undercoat layer provided on one surface thereof, and a stimulable phosphor layer (hereinafter, simply referred to as "phosphor layer"). ) And a protective layer. The undercoat layer is provided mainly for improving the adhesion between the phosphor layer and the support, and is mainly made of a soft resin. Light-reflective fine particles may be added to the undercoat layer to increase the reflectance of stimulating light, or conductive powder or whiskers may be added to prevent charging of the panel.

The phosphor layer generally comprises a stimulable phosphor and a binder containing and supporting the stimulable phosphor in a dispersed state. The stimulable phosphor absorbs radiation such as X-rays,
It has the property of exhibiting stimulated emission when irradiated with excitation light. Therefore, the radiation transmitted through the subject or emitted from the subject is absorbed by the phosphor layer of the radiation image conversion panel in proportion to the amount of the radiation, and the radiation image of the subject or the subject is stored on the panel in accumulating radiation energy. Formed as an image. This accumulated image can be emitted as stimulated emission light by irradiating the excitation light,
By reading the stimulated emission light photoelectrically and converting it into an electric signal, it becomes possible to image a stored image of radiation energy.

The radiation image conversion method is a very advantageous image forming method as described above, but the radiation image conversion panel used in this method is also high in the same way as the intensifying screen used in the conventional radiography. It is desired to provide sensitivity and good image quality (sharpness, granularity, etc.). The sensitivity of the radiation image conversion panel basically depends on the total stimulated emission of the stimulable phosphor contained in the panel,
The total amount of light emission depends not only on the emission luminance of the stimulable phosphor itself but also on the content of the stimulable phosphor in the phosphor layer. The high content of stimulable phosphor also
This means that absorption of radiation such as X-rays is also large, so that higher sensitivity is obtained and at the same time, image quality (particularly, granularity) is improved. On the other hand, when the content of the stimulable phosphor in the phosphor layer is constant, the more the stimulable phosphor particles are densely packed, the thinner the layer can be. The spread of light can be reduced, and relatively high sharpness can be obtained.

A radiation image conversion panel obtained by forming a phosphor layer on a support and compressing the phosphor layer is disclosed in JP-A-59-126299 and JP-A-59-126299.
-126300. In the radiation image conversion panel obtained in this way, the density of the phosphor in the phosphor layer was made higher than that of the conventional radiation image conversion panel by compressing the phosphor layer. As a result, this radiation image conversion panel was able to improve sharpness.

However, a radiation image conversion panel manufactured by adhering an undercoat layer and a phosphor layer by a compression process,
When used repeatedly, there is a problem that a crack is formed near the interface between the undercoat layer and the phosphor layer. Since the crack appears as an artifact on the image, if the crack enters the radiation image conversion panel, a good diagnostic image cannot be obtained. It has been found that this crack is caused by insufficient adhesion between the undercoat layer and the phosphor layer, but at present, no sufficient solution has been obtained so far.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and achieve the following objects. That is, the present invention is excellent in the suitability of the undercoat layer-phosphor layer for compression fusion treatment, and has a strong adhesive force between the undercoat layer and the phosphor layer. An object of the present invention is to provide a radiation image conversion panel and a method for manufacturing the same.

[0010]

Means for solving the above problems are as follows. <1> On a support, at least an undercoat layer and a phosphor layer containing a binder and a stimulable phosphor are provided in this order, and the undercoat layer has a non-crosslinkable organic compound having a molecular weight of 900 or less. The compound was added in an amount of 1 to the total solid weight of the undercoat layer.
A radiation image conversion panel containing 2 to 35% by weight. <2> The phosphor layer is formed by bonding a phosphor sheet formed using a liquid containing a binder and a stimulable phosphor to the undercoat layer while heating and compressing the phosphor sheet. A radiation image conversion panel according to <1>. <3> The above-mentioned <1 which contains the non-crosslinkable organic compound in an amount of 15 to 30% by weight based on the total solid weight of the undercoat layer.
> Or <2>. <4> The radiation image conversion panel according to any one of <1> to <3>, wherein the non-crosslinkable organic compound has a molecular weight of 500 or less. <5> The radiation image storage panel according to any one of <1> to <4>, wherein the non-crosslinkable organic compound contains a plasticizer. <6> the non-crosslinkable organic compound is a fatty acid ester,
The radiation image conversion panel according to any one of the above items <1> to <5>, containing at least one selected from a phthalate ester and a phosphate ester. <7> The radiation image conversion panel according to any one of <1> to <6>, wherein the undercoat layer contains an acrylic resin. <8> The radiation image conversion panel according to any one of <1> to <7>, wherein the undercoat layer has a thickness of 10 to 40 μm. <9> The radiation image conversion panel according to any one of <1> to <8>, wherein the phosphor layer contains a thermoplastic elastomer. <10> a step of forming an undercoat layer on a support, a step of forming a phosphor sheet using a liquid containing a binder and a stimulable phosphor, and a step of forming the phosphor sheet into the undercoat layer Forming a phosphor layer by heating and compressing to form a phosphor layer, wherein the undercoat layer comprises a non-crosslinkable organic compound having a molecular weight of 900 or less. 12 to the total solid weight of
A method for producing a radiation image storage panel, characterized by containing 35% by weight.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a radiation image conversion panel according to the present invention will be described in detail. The radiation image storage panel of the present invention has an undercoat layer and a phosphor layer on a support, and further has other layers as necessary.

[Undercoat layer] The undercoat layer is used to enhance the bond between the support and the phosphor layer, or the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel.
It is provided in order to improve. The undercoat layer contains a non-crosslinkable organic compound having a molecular weight of 900 or less (hereinafter, sometimes referred to as a “low molecular weight organic component”) and a binder, and further contains other components as necessary. Become.

(Low-Molecular-Weight Organic Component) The present invention is characterized in that the undercoat layer contains a non-crosslinkable organic compound having a molecular weight of 900 or less in an amount of 12 to 35% by weight based on the total solid content of the undercoat layer. Due to this, the undercoat layer-phosphor layer has excellent suitability for compression-fusion treatment, and also increases the adhesive force between the undercoat layer and the phosphor layer so that cracks are less likely to occur even when used repeatedly, and durability is high. And a radiation image conversion panel having a good image quality can be obtained.

The amount of the non-crosslinkable organic compound added must be 12 to 35% by weight, preferably 15 to 30% by weight, based on the total solid weight of the undercoat layer.
The addition amount is 12% based on the total solid weight of the undercoat layer.
If the amount is less than 10% by weight, the adhesion between the undercoat layer and the phosphor layer is insufficient, and cracks occur near the interface due to repeated use, and excellent durability cannot be obtained. On the other hand, 35
If the content is more than 10% by weight, it becomes difficult to adhere the phosphor layer uniformly and smoothly when the phosphor layer is fused onto the undercoat layer by a compression treatment. Further, the addition amount is 15 to 3 with respect to the total solid content weight of the undercoat layer.
The amount of 0% by weight is more preferable because the balance between durability and uniform adhesion can be obtained. Here, the total solid content weight of the undercoat layer in the present invention, the undercoat layer,
When an inorganic compound is contained as the other component, the total solid weight excluding the inorganic compound, that is, the non-crosslinkable organic compound, the binder, and the other components other than the inorganic compound Represents the total weight of the solid content consisting of the components, and when the undercoat layer does not contain an inorganic compound as the other component, the non-crosslinkable organic compound, the binder, and the other component And the total weight of the solid content consisting of

The non-crosslinkable organic compound has a molecular weight of 90
It must be 0 or less, but preferably 500 or less. When the molecular weight of the non-crosslinkable organic compound exceeds 900, the effect of durability is reduced. Further, it is more preferable that the molecular weight of the non-crosslinkable organic compound is 500 or less from the viewpoint of durability.

The non-crosslinkable organic compound has a molecular weight of 90
There is no particular limitation as long as it is 0 or less, and any conventionally known non-crosslinkable organic compound may be used. The non-crosslinkable organic compound is preferably a plasticizer from the viewpoint of durability. Specific examples of the non-crosslinkable organic compound,
For example, fatty acid esters, phthalic acid esters, phosphoric acid esters and the like are preferably exemplified. The non-crosslinkable organic compound may be used alone or in combination of two or more.

(Binder) The binder is contained in the undercoat layer in order to improve coating moldability and durability.
Specific examples of the binder include a soft acrylic resin, a soft polyurethane resin, a soft polyester resin, a soft polyvinyl acetate resin, and the like. Of these,
From the viewpoint of durability and handleability, a soft acrylic resin is preferable.

(Other Components) -Solvent- As the other components, a solvent may be used in order to sufficiently mix the non-crosslinkable organic compound, the binder and the like and prepare a uniformly dispersed coating solution. it can. Specific examples of the solvent include, for example, 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.

-Inorganic compound- As the other components, an inorganic compound such as a conductive agent, a coloring agent, a light-reflective substance, or a light-absorbing substance can be added. These can be appropriately selected according to the purpose of the undercoat layer, and additives other than the above may be added. Specific examples of the inorganic compound are not particularly limited, and any conventionally known inorganic compounds can be used.

(Formation of Undercoat Layer) The undercoat layer is formed of a liquid containing the non-crosslinkable organic compound and a binder (hereinafter, referred to as “liquid”).
It is referred to as "coating solution for forming an undercoat layer". ) Is coated on the support and dried. The coating liquid for forming the undercoat layer is prepared by dispersing other components such as the non-crosslinkable organic compound, the binder, and the solvent using a conventionally known disperser such as a propeller mixer or a homogenizer.

The coating solution for forming an undercoat layer prepared as described above is applied to the surface of a support for a radiation image storage panel of the present invention to form a coating film of the coating solution. 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 method for drying the coating liquid is not particularly limited, and a conventionally known drying method can be used. The thickness of the obtained undercoat layer is preferably from 10 to 40 µm, more preferably from 15 to 30 µm. If the thickness of the undercoat layer is less than 10 μm, the durability may be poor,
On the other hand, if it is thicker than 40 μm, the protrusion from the cross section or the like may cause a problem during panel processing.

Further, as described in JP-A-59-200200, in order to improve the sharpness of the obtained image, the surface of the undercoat layer formed on the support is provided with fine irregularities. May be formed.

As the undercoat layer, for example, an adhesion-imparting layer in which a polymer substance such as gelatin is coated on the surface of the support, a light-reflective layer made of a light-reflective substance such as titanium dioxide,
And a light absorbing layer made of a light absorbing substance such as carbon black. Each of these layers can be arbitrarily selected according to the purpose, use, and the like of a desired radiation image conversion panel.

[Phosphor Layer] The phosphor layer contains a binder and a stimulable phosphor, and further contains other components as necessary.

(Binder) The binder is preferably a thermoplastic elastomer which has elasticity at room temperature and becomes fluid when heated. Specific examples of the thermoplastic elastomer, for example, polystyrene, polyolefin,
Examples include polyurethane, polyester, polyamide, polybutadiene, ethylene vinyl acetate, polyvinyl chloride, natural rubber, fluorine rubber, polyisoprene, chlorinated polyethylene, styrene-butadiene rubber, and silicone rubber. Of these, polyurethane, polyester,
And polyolefins are more preferred, and polyurethane is particularly preferred.

The binder may be used alone.
Two or more kinds may be used in combination. The binder may be a mixture of two or more kinds of the thermoplastic elastomer and another elastomer. Further, a polymer (for example, an epoxy resin, an acrylic resin, a polyimide resin, or the like) other than the thermoplastic elastomer may be included. Epoxy resins are commonly used as yellowing inhibitors.

(Stimulable Phosphor) The stimulable phosphor is a phosphor which emits stimulable light when irradiated with radiation and then with excitation light. 90
300-500 n with excitation light in the range of 0 nm
Preferably, the phosphor is a phosphor that exhibits stimulated emission in a wavelength range of m. As the stimulable phosphor, a divalent europium-activated alkaline earth metal halide-based phosphor, a cerium-activated alkaline earth metal halide-based phosphor, and a cerium-activated rare earth oxyhalide-based phosphor have high brightness. It is preferable because it shows stimulated emission. However, the stimulable phosphor used in the present invention is not limited to the stimulable phosphor described above, and any phosphor that emits stimulable light when irradiated with radiation and then with excitation light. Any object may be used.

(Other Components) -Solvent- As the other components, the binder and the stimulable phosphor are sufficiently mixed to form a coating solution in which the stimulable phosphor is uniformly dispersed in the binder solution. Can be used to prepare a solvent. Specific examples of the solvent include, for example, 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 of the binder and the stimulable phosphor in the coating solution varies depending on the characteristics of the intended radiation image conversion panel, the type of the stimulable phosphor, and the like. And the stimulable phosphor in a mixing ratio of 1: 1 to 1
1: 100 (weight ratio) is preferred, and 1: 8 to 1:40.
(Weight ratio) is more preferable.

-Dispersant / Plasticizer- As the other components, a dispersant and a plasticizer can be added. The dispersant is for improving the dispersibility of the stimulable phosphor in the coating solution, and the plasticizer is between the binder and the stimulable phosphor in the phosphor layer after formation. It can be used to improve bonding strength. Specific examples of the dispersant include, for example, phthalic acid,
Stearic acid, caproic acid, lipophilic surfactants and the like. Further, as specific examples of the plasticizer, for example,
Phosphoric acid esters such as triphenyl phosphate, tricresyl phosphate, diphenyl phosphate; phthalic acid esters such as diethyl phthalate and dimethoxyethyl phthalate; glycolic acid esters such as ethyl phthalylethyl glycolate and butyl phthalyl butyl glycolate; Polyesters of polyethylene glycol and aliphatic dibasic acid, such as polyesters of ethylene glycol and adipic acid, polyesters of diethylene glycol and succinic acid, and the like are included.

(Formation of Phosphor Layer) The phosphor layer is formed by using a solution containing the binder and the stimulable phosphor (hereinafter, referred to as a “coating solution for forming a phosphor layer”). It is preferable to form the phosphor sheet on the undercoat layer by heating and compressing the phosphor sheet while heating and compressing the undercoat layer, since the adhesive strength between the undercoat layer and the phosphor layer can be improved.

The phosphor sheet is formed by uniformly applying the coating solution for forming the phosphor layer on the surface of a temporary support for forming the phosphor sheet and drying. The coating solution for forming the phosphor layer, the binder described above, a stimulable phosphor,
Other components such as a solvent are dispersed and prepared by a conventionally known disperser such as a propeller mixer or a homogenizer. The viscosity at 25 ° C. of the obtained coating liquid for forming a phosphor layer is preferably from 10 to 100 Pa · s.

In order to uniformly apply the coating solution for forming a phosphor layer prepared as described above to the surface of the temporary support, a usual coating means such as a doctor blade, a roll coater, a knife coater, etc. Can be performed. Next, the coating liquid is dried and peeled from the temporary support to obtain a phosphor sheet to be a phosphor layer of the radiation image conversion panel. 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. The thickness of the phosphor sheet can be appropriately selected according to the purpose, but is preferably 100 to 400 μm.

The temporary support may be, 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 radiation image converter. The support for the panel can be arbitrarily selected from known materials. Specific examples of such materials include, for example, films of plastic substances such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, and polycarbonate, aluminum foil, metal sheets such as aluminum alloy foil, ordinary paper, and baryta. Examples include paper, resin-coated paper, pigment paper containing a pigment 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.

The phosphor layer is preferably formed by bonding the phosphor sheet formed as described above to the undercoat layer while heating and compressing the phosphor sheet.
It is not limited to this method. The method of bonding the phosphor sheet while heating and compressing it will be described in detail in the method of manufacturing a radiation image storage panel of the present invention described later.

[Support] The support can be arbitrarily selected from the same materials as the temporary support used in forming the phosphor sheet. That is, a support for the radiation image conversion panel is prepared separately from the phosphor sheet formed as described above. As the support, among others, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate and the like are preferable from the viewpoint of handleability. The thickness of the support is not particularly limited and can be appropriately selected depending on the intended purpose, but is preferably 50 to 500 μm.

[Other Layers] As the other layers (films), a transparent protective film may be formed on the phosphor layer to physically and chemically protect the phosphor layer. it can. The transparent protective film, for example, cellulose acetate,
Cellulose derivatives such as nitrocellulose; or polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate,
A solution prepared by dissolving a transparent high-molecular substance such as a synthetic high-molecular substance such as a vinyl chloride-vinyl acetate copolymer or a fluororesin (for example, a fluoroolefin-vinyl ether copolymer) in an appropriate solvent is used. It can be formed by coating on the surface of the phosphor layer. A crosslinking agent such as polyisocyanate can be used as appropriate.
Alternatively, a plastic sheet made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide, or the like; a protective film forming sheet such as a transparent glass plate is separately formed, and an appropriate adhesive is applied to the surface of the phosphor layer. It can also be formed by a method such as bonding by using. The thickness of the protective film is usually about 0.1 to 20 μm. Further, for the purpose of improving the sharpness of the obtained image, a coloring layer which absorbs excitation light but does not absorb stimulated emission light may be added to at least one of the above-mentioned layers (Japanese Patent Publication No. 59-1984). 23400
No.).

In the radiation image conversion panel of the present invention, cracks in the vicinity of the interface due to repeated use, which have been considered as a problem, are unlikely to occur. Therefore, artifacts on images due to the cracks are suppressed, and the purpose is particularly for medical diagnosis. It is very useful in direct medical radiography at the time of X-ray radiography.

Hereinafter, a method for manufacturing the radiation image storage panel of the present invention will be described. In the method for producing a radiation image storage panel of the present invention, a step of forming an undercoat layer on a support (hereinafter, referred to as an “undercoat layer forming step”) and a step of forming a phosphor sheet (hereinafter, “phosphor”) A step of forming a phosphor layer using the phosphor sheet (hereinafter, referred to as a “phosphor layer forming step”).
And, if necessary, a step of forming another layer (hereinafter, referred to as “another layer forming step”). Hereinafter, each step will be described.

The step of forming the undercoat layer, the step of forming the phosphor sheet, and the step of forming the other layers can be performed by the method already described for the radiation image storage panel of the present invention. The undercoat layer, the phosphor sheet, and the other layers can be formed.

[Phosphor Layer Forming Step] In the phosphor layer forming step, the phosphor sheet is adhered onto the undercoat layer while being heated and compressed (hereinafter sometimes referred to as “heating compression processing”). This is a step of forming a phosphor layer.

Examples of the compression device used for the heat compression treatment include a conventionally known compression device such as a calender roll and a hot press. From the viewpoint of stability and uniformity, a calender roll is used. Is preferred.
The heat compression treatment by the calender roll, the phosphor sheet is placed on a support on which the undercoat layer is formed,
This is performed by passing the phosphor sheet between rollers heated above the softening temperature or above the melting point at a constant speed (feed speed). However, the compression device used in the present invention may be any device as long as it can compress the phosphor sheet while heating it.

The softening temperature is a Vicat softening temperature. This is a standard indenter with a load of 1 kg (diameter 1
mm) is measured by measuring the temperature at which 1 mm of the sample (polymer) has penetrated from the surface of the sample (polymer).
5 is performed.

The pressure during the heating and compression treatment is 50 kg
w / cm ² or more is common, and 200 to 700 kgw / c
m ² is preferred. The heating temperature (upper and lower roll temperatures) during the heat compression treatment is generally equal to or higher than the softening temperature or the melting point as described above, and is preferably performed at a temperature 10 to 50 ° C. higher than the softening temperature. In general, it is preferable to set the lower roll temperature higher than the upper roll temperature or to perform the upper and lower roll temperatures at the same temperature. The feed speed is preferably from 0.1 to 5.0 m / min.

In the method of manufacturing a radiation image storage panel according to the present invention, the undercoat layer may contain a non-crosslinkable organic compound having a molecular weight of 900 or less in an amount of from 12 to 10% by weight of the total solid content of the undercoat layer.
It is characterized by containing 35% by weight.
It is possible to improve the suitability of the undercoat layer-phosphor layer for compression-fusion treatment, and also to increase the adhesive force between the undercoat layer and the phosphor layer, so that cracks are less likely to occur even when used repeatedly and have good durability. A radiation image conversion panel can be manufactured.

[0046]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. (Example 1) [Formation of phosphor sheet] The following component 1 was added to a methyl ethyl ketone solvent, dispersed with a propeller mixer, and a phosphor layer-forming coating liquid having a viscosity of 30 Pa · s (25 ° C) (binder) / Phosphor ratio = 1/20). —Component 1—Stimulable phosphor: BaFBr _0.85 I _0.15 : Eu 2 ⁺ ... 200 g Binder: polyurethane elastomer 7.4 g (T5265H Cross-linking agent: polyisocyanate 0.6 g (Coronate HX, manufactured by Nippon Polyurethane Co., Ltd.) Yellowing inhibitor: Epoxy resin 2.0 g (EP1001, manufactured by Yuka Shell Epoxy Co., Ltd.) This phosphor layer forming coating liquid is coated with a silicon release agent. It was coated on polyethylene terephthalate (temporary support, thickness 180 μm), dried, and then peeled off from the temporary support to form a phosphor sheet (thickness 320 μm).

[Formation of Undercoat Layer] The following component 2 was added to 220 g of methyl ethyl ketone and mixed using a propeller mixer, and the coating liquid for forming an undercoat layer having a viscosity of 5 to 10 Pa · s (25 ° C.) (low molecular weight organic compound) Ingredient: containing 19% by weight of the total solid content excluding inorganic compounds). - component 2 gadolinium oxide (Gd ₂ O ₃₎ fine particles ........... 30 g (particle 90 wt% contain in the range of particle diameter 1 to 5 [mu] m) Binder: soft acrylic resin, 150 g (Chris Coat P-1018GS, manufactured by Dainippon Ink and Chemicals, Inc., solid content: 20% by weight) Low molecular weight organic component: di-2-ethylhexylase Rate 7.0 g (molecular weight: 413) Conductive agent: ZnO whisker 10 g Colorant: ultramarine blue ... 0.4 g Polyethylene terephthalate (support) having a thickness of 300 μm is placed horizontally on a glass plate, and the above-mentioned coating liquid for forming an undercoat layer is applied using a doctor blade. After uniform coating on the support, the coating film is dried To form an undercoat layer on the support (thickness 20 [mu] m).

[Manufacture of radiation image conversion panel] The phosphor sheet is placed on the undercoat layer formed on the support, heated and compressed, and the phosphor layer (thickness: 220 µm)
Was formed. Compression is performed using a calender roll, pressure 500 kgw / cm ² , heating temperature (upper and lower roll temperatures)
This was continuously performed under the conditions of 45 ° C. and a feed rate of 0.5 m / min. By this compression, the phosphor sheet and the undercoat layer on the support were completely fused. After this heating and compression treatment, a transparent film of polyethylene terephthalate having a polyester adhesive applied on one side (9 μm thick)
Was subjected to thermocompression bonding so that the adhesive-coated surface was bonded to the phosphor layer surface to form a transparent protective film. As described above, a radiation image conversion panel composed of the support, the undercoat layer, the phosphor layer, and the transparent protective film was manufactured.

<Evaluation of Adhesive Force> The adhesive force between the undercoat layer and the phosphor layer of the obtained radiation image conversion panel was evaluated as follows. In the obtained radiation image conversion panel, make a cut from the transparent protective film to the undercoat layer with a razor, gradually bending the cut part from a small curvature to a large curvature so that the transparent protective film is on the outside, The evaluation value was defined as a radius of curvature at which the interface between the undercoat layer and the phosphor layer was not separated. It means that the adhesive force is so strong that the separation of the interface does not occur with a small radius of curvature. Table 1 shows the results.

<Suitability of Compression Fusion Processing> The surface state of the phosphor layer after performing fusion by heating and compression processing over a length of 50 cm is visually observed, and whether the phosphor layer is uniformly and smoothly adhered. The evaluation was made based on the following criteria. Table 1 shows the results. Irregularities are not visible on the surface of the phosphor layer ...

(Example 2) In Example 1, the amount of di-2-ethylhexyl azelate used in the undercoat layer forming coating solution was changed to 11 g, and the undercoat layer forming coating solution (low molecular weight organic component: A radiation image conversion panel was manufactured in the same manner as in Example 1 except that the solid content (containing 27% by weight of the total solid content excluding the inorganic compound) was prepared, and the same evaluation as in Example 1 was performed. Table 1 shows the results.

Example 3 In Example 1, the di-2-ethylhexyl azelate used in the undercoat layer forming coating solution was replaced with ethylphthalylethyl glycolate (molecular weight: 280) to form the undercoat layer. Except for preparing the liquid, a radiation image conversion panel was manufactured in the same manner as in Example 1,
The same evaluation as in Example 1 was performed. Table 1 shows the results.

Example 4 In Example 3, the amount of ethylphthalylethyl glycolate used in the undercoat layer forming coating solution was changed to 11 g, and the undercoat layer forming coating solution (low molecular weight organic component: inorganic A radiation image conversion panel was manufactured in the same manner as in Example 3 except that the solid content (containing 27% by weight of the total solid content excluding the compound) was prepared, and the same evaluation as in Example 3 was performed. Table 1 shows the results.

Example 5 In Example 1, di-2-ethylhexyl azelate used in the undercoat layer forming coating solution was replaced with tricresyl phosphate (molecular weight: 368).
A radiation image conversion panel was manufactured in the same manner as in Example 1 except that the coating liquid for forming an undercoat layer was prepared in place of the above, and the same evaluation as in Example 1 was performed. Table 1 shows the results.

Comparative Example 1 In Example 1, the amount of di-2-ethylhexyl azelate used in the undercoat layer forming coating solution was changed to 3 g, and the undercoat layer forming coating solution (low molecular weight organic component: A radiation image storage panel was manufactured in the same manner as in Example 1 except that the solid content (containing 9% by weight of the total solid content excluding the inorganic compound) was prepared, and the same evaluation as in Example 1 was performed. Table 1 shows the results.

(Comparative Example 2) In Example 3, the amount of ethylphthalylethyl glycolate used in the undercoat layer forming coating solution was changed to 3 g, and the undercoat layer forming coating solution (low molecular weight organic component: inorganic A radiation image storage panel was manufactured in the same manner as in Example 3 except that the solid content except for the compound was 9% by weight, and the same evaluation as in Example 3 was performed. Table 1 shows the results.

Comparative Example 3 In Example 3, the amount of ethylphthalylethyl glycolate used in the undercoat layer forming coating solution was changed to 18 g, and the undercoat layer forming coating solution (low molecular weight organic component: inorganic A radiation image conversion panel was manufactured in the same manner as in Example 3 except that the solid content (containing 38% by weight of the total solid content excluding the compound) was prepared, and the same evaluation as in Example 3 was performed. Table 1 shows the results.

[0058]

[Table 1]

From the results shown in Table 1, the radiation image conversion panels of the present invention of Examples 1 to 5 have smaller radii of curvature as compared with Comparative Examples 1 and 2 in which the amount of the low molecular weight organic component added is small.
It can be seen that the adhesion between the undercoat layer and the phosphor layer is strong. On the other hand, in Comparative Example 3 in which the amount of the low-molecular weight organic component added was large, the radius of curvature was small and the adhesive strength between the undercoat layer and the phosphor layer was strong. Poor processing suitability. Further, in order to confirm that the radiation image storage panel of the present invention is less likely to crack even when used repeatedly and has excellent durability, the radius of curvature is 14 m.
The radiation image conversion panel of Example 1 with m and the radiation image conversion panel of Comparative Example 1 with the radius of curvature of 17 mm were repeatedly used at the same time, and the occurrence of artifacts on the image was observed. As a result, when an artifact on an image occurred in the radiation image conversion panel of Comparative Example 1, the radiation image conversion panel of Example 1 had no problem. Therefore, it was found that the radiation image conversion panels of Examples 1 to 5 of the present invention having a small radius of curvature were less likely to crack even when repeatedly used, and had excellent durability.

[0060]

According to the present invention, the undercoat layer-phosphor layer has excellent suitability for the compression-fusion treatment, and the adhesion between the undercoat layer and the phosphor layer is strong. A radiation image conversion panel having good durability and a method for manufacturing the same can be provided.

Claims (10)

[Claims] 1. A support comprising at least an undercoat layer on a support,
And a phosphor layer containing a binder and a stimulable phosphor, in this order, the undercoat layer, a non-crosslinkable organic compound having a molecular weight of 900 or less, based on the total solid weight of the undercoat layer 12-35
A radiation image conversion panel comprising: 2. The phosphor layer is formed by bonding a phosphor sheet formed using a liquid containing a binder and a stimulable phosphor onto the undercoat layer while heating and compressing the phosphor sheet. The radiation image conversion panel according to claim 1. 3. The radiation image conversion panel according to claim 1, wherein the non-crosslinkable organic compound is contained in an amount of 15 to 30% by weight based on the total solid content of the undercoat layer. 4. The non-crosslinkable organic compound having a molecular weight of 5
4. The radiation image conversion panel according to claim 1, wherein the radiation image conversion panel is equal to or less than 00. 5. The radiation image storage panel according to claim 1, wherein the non-crosslinkable organic compound contains a plasticizer. 6. The radiation image conversion panel according to claim 1, wherein the non-crosslinkable organic compound contains at least one selected from fatty acid esters, phthalic acid esters, and phosphoric acid esters. 7. The radiation image storage panel according to claim 1, wherein the undercoat layer contains an acrylic resin. 8. The undercoat layer having a thickness of 10 to 40 μm
The radiation image conversion panel according to any one of claims 1 to 7, wherein 9. The radiation image conversion panel according to claim 1, wherein the phosphor layer contains a thermoplastic elastomer. 10. A step of forming an undercoat layer on a support, a step of forming a phosphor sheet using a liquid containing a binder and a stimulable phosphor, Forming a phosphor layer by heating and compressing the undercoat layer to form a phosphor layer, comprising: a non-crosslinkable organic compound having a molecular weight of 900 or less in the undercoat layer. 12 to 35 based on the total solid weight of the undercoat layer
A method for producing a radiation image storage panel, characterized in that it is contained by weight.