Radiographic intensifying screen

A radiographic intensifying screen having at least a fluorescent layer and a protective layer on a support, wherein the protective layer has a multi-layer structure comprising at least one layer of an organic macromolecule film and a film-forming resin layer provided on the surface of the organic macromolecule film at least on the side which is not in contact with the fluorescent layer, and the resin of the film-forming resin layer is different from the resin of the organic macromolecule film.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a radiographic intensifying screen
 (hereinafter referred to as "intensifying screen"). More particularly, the
 present invention relates to an intensifying screen excellent in
 durability.
 2. Discussion of Background
 An intensifying screen is used in intimate contact with an X-ray film in
 order to improve sensitivity of photographing in the field of medical
 radiographing for medical diagnosis or of industrial radiographing for
 non-destructive inspection of materials. Generally, on the surface of the
 intensifying screen, there are made abrasions or defects by an X-ray film,
 or dirt is attached thereon. Also, the surface of the intensifying screen
 is often damaged by contaminants including dust entered between the
 intensifying screen and the X-ray film, and also chemical materials
 contained in cleaners for the intensifying screen and the X-ray film are
 sometimes invaded into the intensifying screen to stain or color the
 screen. The above-mentioned various defects and damages cause unusual
 artifacts on a radiograph or make sensitivity lower. In order to prevent
 the performance of the intensifying screen from deteriorating, it is usual
 to provide a transparent protective layer on the surface of the
 intensifying screen which is brought into direct contact with an X-ray
 film.
 Heretofore, in a method for forming a protective layer, a protective
 layer-forming coating solution having an appropriate viscosity is prepared
 by dissolving cellulose derivatives such as cellulose acetate, nitro
 cellulose and cellulose acetate butyrate, polyvinyl chloride, polyvinyl
 acetate, vinyl chloride-vinyl acetate copolymer, polycarbonate, polyvinyl
 butyral, polymethyl methacrylate, polyvinyl formal, polyurethane or other
 resins in a solvent, and the coating solution thus prepared is coated on a
 previously formed fluorescent layer and dried to form a protective layer
 thereon. Alternatively, a protective layer previously formed in the form
 of a film, such as an organic macromolecule film including polyethylene
 terephthalate, polyethylene, polyvinylidene chloride, polyamide and the
 like, may be laminated on a fluorescent layer to form a protective layer.
 It is useful for improving durability of an intensifying screen to make a
 protective layer thick, but if the thickness of the protective layer
 increases, sharpness is lowered, and therefore it has been difficult to
 improve both durability and image quality at the same time.
 As a method for improving durability and handling property of an
 intensifying screen or a radiation image-conversion panel using an
 photostimulable phosphor, Japanese Unexamined Patent Publication No.
 310900/1992, Japanese Unexamined Patent Publication No. 309898/1992 and
 Japanese Unexamined patent Publication No. 75097/1994 disclose a
 protective layer formed on the surface of a fluorescent layer by coating a
 protective layer-forming coating solution containing an organic
 solvent-soluble fluorocarbon resin having a polysiloxane-structured
 oligomer, a perfluoroalkyl group-containing oligomer, a perfluoroolefin
 resin powder or a silicone resin powder added therein.
 Among these protective layer-forming methods, when a coating solution
 prepared by dissolving a protective layer-forming resin in a solvent is
 coated on a fluorescent layer, a part of the coating solution is soaked
 into the inside of the fluorescent layer and accordingly a protective
 layer is formed on the fluorescent layer without making a boundary between
 the two layers. Thus, the protective layer is firmly bonded with the
 fluorescent layer, and peeling of the protective layer off the
 intensifying screen and occurrence of pinholes on the protective layer due
 to the presence of contaminants can be avoided. Also, when the
 above-mentioned organic solvent-soluble fluorocarbon resin is used as a
 protective layer-forming resin, anti-fouling property is improved and a
 coefficient of friction is lowered, thereby improving durability
 resistance. Further, since a contact angle between water and the resin is
 large, even if pinholes are produced, a chemical material from an X-ray
 film is hardly soaked and spot-like sensitivity degradation does not
 substantially occur, thus improving pinhole resistance.
 However, when a protective layer is formed by coating a solution, a
 starting material used is limited to a solvent-soluble resin, and
 accordingly durability resistance is poor as compared with a method
 wherein an organic macromolecule film such as polyethylene terephthalate
 is laminated on a fluorescent layer to form a protective layer. Further,
 when a binder resin content in a fluorescent layer is reduced in order to
 improve sharpness, a protective layer-forming coating solution is soaked
 into the fluorescent layer when the protective layer-forming coating
 solution is coated on the fluorescent layer, and a protective layer having
 a sufficient thickness can not be formed. On the other hand, when a
 protective layer-forming coating solution is coated in a large amount on a
 fluorescent layer in order to form a protective layer having a sufficient
 thickness, the protective layer-forming coating solution is soaked into
 the fluorescent layer, thereby causing such problems as lowering sharpness
 or generating foams during coating.
 Unlike the method for forming a protective layer by coating a solution, in
 the method for forming a protective layer by laminating an organic
 macromolecule film on a fluorescent layer, there is caused no problem of
 soaking with a protective layer-forming coating solution. Particularly
 when a polyethylene terephthalate film is used as a protective layer to be
 laminated, as compared with the method of using a protective layer-forming
 coating solution, abrasion resistance and solvent resistance are excellent
 and water vapor permeability and gas permeability are low, thereby
 providing excellent anti-staining property to a chemical material eluded
 from an X-ray film. However, as compared with a protective layer formed by
 coating a solution, adhesive strength of a protective layer laminated on a
 fluorescent layer is poor and therefore the laminated protective layer is
 liable to be peeled and pinholes are liable to occur when contaminants
 invade into between an intensifying screen and an X-ray film. Further,
 through the pinholes, various contaminants invade into the intensifying
 screen, thereby causing a problem of producing spot-like sensitivity
 degradation parts.
 Thus, both a protective layer formed by coating a solution on a fluorescent
 layer and a protective layer formed by laminating an organic macromolecule
 film on a fluorescent layer respectively provide various advantages and
 disadvantages, and it has been difficult to satisfy all of requirements.
 Also, recently, radiographing is automatically conducted in a labor saving
 manner, and an X-ray film is automatically conveyed and charged into a
 radiographing apparatus. Further, a film changer for automatically taking
 an X-ray film after radiographing and a film-conveying apparatus of a
 cassetteless X-ray TV are often used. Under these recent circumstances, an
 intensifying screen is demanded to be more improved in respect of
 anti-staining property, handling properties including an X-ray
 film-conveying property, and the like.
 An object of the present invention is to provide an intensifying screen
 which satisfies satisfactory image quality, durability and handling
 performances at the same time.
 In order to improve durability and handling performances of an intensifying
 screen without degrading image quality, the present inventors have studied
 about materials used for a protective layer of an intensifying screen and
 its structure, and have found that the material quality and the structure
 of the protective layer are closely related to durability and handling
 performances of the intensifying screen. The present invention is made on
 the basis of this finding.
 SUMMARY OF THE INVENTION
 The present invention provides a radiographic intensifying screen having at
 least a fluorescent layer and a protective layer on a support, wherein the
 protective layer has a multi-layer structure comprising at least one layer
 of an organic macromolecule film and a film-forming resin layer provided
 on the surface of the organic macromolecule film at least on the side
 which is not in contact with the fluorescent layer, and the resin of the
 film-forming resin layer is different from the resin of the organic
 macromolecule film.
 The intensifying screen having the protective layer of the above-mentioned
 structure is improved not only in image quality but also in pinhole
 resistance, anti-staining property, anti-fouling property, durability and
 handling performances including X-ray film-conveying performance, and the
 like.

DETAILED DESCRIPTION OF THE INVENTION
 Hereinafter, the present invention is further explained in more detail.
 FIG. 1 is a cross-section of a radiographic intensifying screen, which
 illustrates an embodiment of the invention. In this FIG., 1 is a support,
 2 is a flourescent layer, and 3 and 4 form a protective layer, wherein 3
 is an organic macromolecule film and 4 is a film-forming resin layer.
 In a general method for producing the intensifying screen of the present
 invention, a fluorescent layer is formed by mixing a predetermined amount
 of phosphor with a binder such as nitro cellulose, adding an organic
 solvent to the mixture to form a phosphor-coating solution having an
 appropriate viscosity, coating the phosphor-coating solution on a support
 by a knife coater, a roll coater or the like and drying the support thus
 coated.
 The intensifying screen of the present invention may have a
 light-reflecting layer, a light-absorbing layer or a metal foil layer
 between the fluorescent layer and the support. In such a case, the support
 is previously provided with the light-reflecting layer, the
 light-absorbing layer or the metal foil layer, and the above-mentioned
 phosphor-containing solution is coated thereon and is dried to form a
 fluorescent layer. Also, it is preferable to provide an electroconductive
 layer on the back side of the support or between the support and the
 fluorescent layer, thus achieving a antistatic effect without coating an
 antistatic agent on the surface. Such an electroconductive layer can be
 formed by directly coating an organic electroconductive material or an
 inorganic electroconductive material such as ZnO, SnO.sub.2, In.sub.2
 O.sub.3 and carbon, or dispersing electroconductive materials in a binder
 and coating the dispersion. It is preferable to adjust electroconductivity
 of the electroconductive layer so as to provide a surface resistance value
 of from 10.sup.7 to 10.sup.13 .OMEGA. after forming the electroconductive
 layer.
 Examples of the support used for the intensifying screen of the present
 invention include a film of cellulose acetate, cellulose propionate,
 cellulose acetate-butyrate, polyester such as polyethylene terephthalate
 or the like, polystyrene, polymethylmethacrylate, polyamide, polyimide,
 vinyl chloride-vinyl acetate copolymer, polycarbonate, or the like, bulk
 board paper, resin-coated paper, ordinary paper, aluminum alloy foil, and
 the like. When the above-mentioned plastic films or papers are used as a
 support for the intensifying screen of the present invention, a
 light-absorbing material such as carbon black or a light-reflecting
 material such as titanium dioxide and calcium carbonate may be previously
 kneaded therein. As a phosphor for the intensifying screen of the present
 invention, any phosphor can be used, provided that it emits light by X-ray
 excitation, examples of which include Gd.sub.2 O.sub.2 S:Tb, Y.sub.2
 O.sub.2 S:Tb, (Gd,Y).sub.2 O.sub.2 S: Tb, La.sub.2 O.sub.2 S:Tb,
 (Gd,Y).sub.2 O.sub.2 S:Tb:Tm, GdTaO.sub.4 :Tb, Gd.sub.2 O.sub.3.Ta.sub.2
 O.sub.5.B.sub.2 O.sub.3 :Tb, CaWO.sub.4, BaSO.sub.4 :Pb, LaOBr:Tm,
 LaOBr:Tb, HfO.sub.2 :Ti, HfP.sub.2 O.sub.7 :Cu, CdWO.sub.4, YTaO.sub.4,
 YTaO.sub.4 :Tm, YTaO.sub.4 :Nb, ZnS:Ag, BaFCl:Eu and the like.
 A binder used for the intensifying screen of the present invention is not
 especially limited, and conventionally known binders for an intensifying
 screen can be used, examples of which include nitro cellulose, cellulose
 acetate, ethylcellulose, polyvinyl butyral, linear polyester, polyvinyl
 acetate, vinylidene chloride-vinyl chloride copolymer, vinyl
 chloride-vinyl acetate copolymer, polyalkyl (meth)acrylate, polycarbonate,
 polyurethane, cellulose acetate butyrate, polyvinyl alcohol, gelatin,
 polysaccharide such as dextrin, gum arabic, and the like.
 An amount of a binder remaining in a fluorescent layer is from 1 to 10
 parts by weight as a solid content to 100 parts by weight of a phosphor in
 view of sharpness, and more preferably from 1 to 6 parts by weight as a
 solid content to 100 parts by weight of a phosphor.
 Examples of an organic solvent used in the preparation of a
 phosphor-coating solution include ethanol, methylethyl ether, butyl
 acetate, ethyl acetate, ethyl ether, xylene and the like. Further, if
 necessary, the phosphor-coating solution may contain a dispersing agent
 such as phthalic acid or stearic acid and a plasticizer such as
 triphenylphosphate or diethylphthalate.
 Hereinafter, a protective layer used for the intensifying screen of the
 present invention is further explained in more details.
 The protective layer of the present invention comprises an organic
 macromolecule film, at least one side of which is provided with a thin
 film-forming resin layer of a resin different from the resin constituting
 the organic macromolecule film, the film-forming resin layer being adhered
 to the organic macromolecule film by heat-transferring a previously made
 thin film-forming resin film to the organic macromolecule film or by
 bonding the previously made thin film-forming resin film to the organic
 macromolecule film by way of an adhesive layer. Alternatively, a solution
 containing a film-forming resin is coated on the organic macromolecule
 film and is dried to form a film-forming resin layer. In order to obtain a
 uniform thin film-forming resin layer, it is preferable to employ the
 latter method, i.e. a resin layer-forming method using a coating solution
 containing the film-forming resin. The film-forming resin layer may be
 previously formed on an organic macromolecule film before the organic
 macromolecule film is provided on a fluorescent layer or it may be formed
 on the organic macromolecule film after the organic macromolecule film is
 provided on the fluorescent layer.
 It is necessary that the film-forming resin layer is provided on at least
 one side of the organic macromolecule film, which is not in contact with
 the fluorescent layer, but it may be provided on both sides of the organic
 macromolecule film. However, in view of sharpness of the finally obtained
 intensifying screen, it is preferable to make the protective layer as thin
 as possible, and accordingly it is preferable to form the film-forming
 resin layer only on the side of the organic macromolecule film, which is
 not in contact with the fluorescent layer.
 The organic macromolecule film itself may have a multi-layer structure. As
 generally conducted, an adhesive layer such as a heat-sensitive adhesive
 layer of a polyester type adhesive is provided on both sides or on the
 side of the organic macromolecule film, which is brought into contact with
 the fluorescent layer, and the organic macromolecule film layer is formed
 on the fluorescent layer by a laminating method. This is a preferable
 method.
 Preferable examples of a resin for constituting the organic macromolecule
 film of the present invention include polyethylene terephthalate,
 polyethylene naphthalate, aramide, polyethylene, polyvinylidene chloride,
 polyamide and the like. More preferable examples include polyethylene
 terephthalate, polyethylene naphthalate and aramide.
 The organic macromolecule film of the present invention has preferably a
 thickness of from 1 to 10 .mu.m, more preferably from 1.5 to 7 .mu.m, most
 preferably from 2 to 5 .mu.m. In order to strengthen the adhesive force
 with the film-forming resin layer, the surface of the organic
 macromolecule film to be adhered may be activated by surface treatment.
 Preferable examples of a resin used as the film-forming resin layer of the
 intensifying screen of the present invention include cellulose derivatives
 such as cellulose acetate, nitro cellulose and cellulose acetate butyrate,
 polyvinyl chloride, polyvinyl butyral, polyvinyl acetate, vinyl
 chloride-vinyl acetate copolymer, polymethylmethacrylate, polycarbonate,
 polyvinyl formal, polyurethane, solvent-soluble fluorocarbon resin,
 polyacryl, and the like.
 It is preferable to incorporate a crosslinking agent, a
 crosslinking-accelerating agent (catalyst) or the like in the film-forming
 resin layer.
 The film-forming resin layer of the intensifying screen of the present
 invention may have a multi-layer structure, and accordingly it is
 preferable to provide an adhesive layer when adhesiveness with the organic
 macromolecule film is insufficient and/or to provide a plastic layer in
 order to relax stress concentrated on the protective layer.
 The film-forming resin layer which is a part of the protective layer of the
 intensifying screen of the present invention, has preferably a thickness
 of from 0.1 to 5 .mu.m, more preferably from 0.3 to 4 .mu.m, most
 preferably from 0.5 to 3 .mu.m.
 In the film-forming resin layer of the intensifying screen of the present
 invention, the uppermost resin layer (which is brought into contact with
 an X-ray film when using) should preferably contain a surface-modifying
 agent such as a polysiloxane structure-containing oligomer, a
 perfluoroalkyl group-containing oligomer or the like in order to improve
 abrasion resistance, anti-staining property and anti-fouling property, and
 further to impart a satisfactory intimate contact with an X-ray film and a
 satisfactory slipping property for improving releasing property, and still
 further to make a contact angle to water larger. The amount of the
 surface-modifying agent varies depending on a degree of achievement of the
 above aimed effect, but is generally not more than 10 wt % of the
 film-forming resin layer, preferably not more than 5 wt %.
 Various combinations of the organic macromolecule film and the film-forming
 resin layer with regard to the protective layer of the present invention
 can be considered, but it is preferable to use polyethylene terephthalate,
 polyethylene naphthalate, or aramide as an organic macromolecule
 film-constituting resin and to use fluorocarbon resin as a film-forming
 resin layer-constituting resin in order to improve durability,
 anti-fouling property or the like of the intensifying screen. It is
 particularly preferable to add a polysiloxane structure-containing
 oligomer or a perfluoroalkyl group-containing oligomer to the fluorocarbon
 resin.
 The thickness of the protective layer of the intensifying screen of the
 present invention is preferably thin in view of sharpness, but preferably
 thick in view of physical durability. In practice, it is preferable to
 adjust the thickness of the total protective layer comprising plural
 layers containing a film-forming resin layer in the range of from 2 to 10
 .mu.m in order not only to satisfy physical durability but also to prevent
 sharpness from deteriorating.
 The intensifying screen of the present invention prepared as mentioned
 above, is excellent in image quality, durability and handling properties
 as compared with conventional intensifying screens obtained by forming
 protective films by laminating conventional organic macromolecule films or
 by coating protective layer-forming coating solutions.
 EXAMPLE
 The present invention is further illustrated by the following Examples but
 should not be limited thereto.
 EXAMPLE 1
 A phosphor coating solution was prepared by mixing 10 parts by weight of
 Gd.sub.2 O.sub.2 S:Tb phosphor having an average particle size of 5.0
 .mu.m, 1 part by weight of vinyl chloride-vinyl acetate copolymer (binder)
 and ethyl acetate as an organic solvent.
 The above prepared phosphor coating solution was coated on a support
 comprising a polyethylene terephthalate film of 250 .mu.m thickness having
 titanium dioxide kneaded therein, which had been previously coated with a
 ZnO whisker particle layer of 20 .mu.m thickness as an electroconductive
 layer. The above phosphor coating solution was uniformly coated in such an
 amount as to provide a dry phosphor coating weight of 50 mg/cm.sup.2 by a
 knife coater, and was dried to form a phosphor layer.
 Thereafter, a protective layer-forming resin solution having 80 parts by
 weight of a fluorocarbon resin ("Lumiflon LF 100C" manufactured by Asahi
 Glass Company Ltd.), 15 parts by weight of a crosslinking agent
 (isocyanate, a curing agent for "Lumiflon LF 100C" manufactured by Asahi
 Glass Company Ltd.) and 5 parts by weight of an alcohol-modified silicone
 oligomer ("X-22-2809" manufactured by Shin-Etsu Kagaku Kogyo Co.)
 dissolved in methyl ethyl ketone was coated on a polyethylene
 terephthalate film of 4.5 .mu.m thickness in such an amount as to provide
 a dry coating thickness of 1.5 .mu.m by a knife coater, thus producing a
 protective layer having a two-layer structure. Further, a polyester type
 adhesive agent was coated in such an amount as to provide 0.5 .mu.m on the
 side, to which the fluorocarbon resin was not coated, and was dried.
 Thereafter, the above protective layer was heat-laminated by way of the
 adhesive layer on the above formed phosphor layer to produce an
 intensifying screen.
 EXAMPLE 2
 An intensifying screen (2) was obtained in the same manner as in Example 1,
 except that a polyethyl naphthalate film having the same thickness was
 used in place of the polyethylene terephthalate of 4.5 .mu.m thickness in
 the preparation of the protective layer.
 EXAMPLE 3
 An intensifying screen (3) was obtained in the same manner as in Example 1,
 except that the alcohol-modified silicone oligomer was not added to the
 protective layer-forming coating solution.
 EXAMPLE 4
 An intensifying screen (4) was obtained in the same manner as in Example 1,
 except that a polyurethane resin (tradename, "Desmolac 4125" manufactured
 by Sumitomo Bayer Urethane Company) was used in place of the fluorocarbon
 resin as a film-forming resin and the amount of the alcohol-modified
 silicone oligomer was increased to 7 parts by weight.
 COMATIVE EXAMPLE
 A comparative intensifying screen (R1) was prepared in the same manner as
 in Example 1, except that a protective layer comprising only a
 polyethylene terephthalate film of 6 .mu.m thickness having a polyester
 type adhesive coated in 0.5 .mu.m thickness was laminated, as a protective
 layer on the phosphor layer formed on the support in the same manner as in
 Example 1, in place of the polyethylene terephthalate, one side of which
 was provided with the fluorocarbon resin layer.
 Further, a comparative intensifying screen (R2) was prepared in the same
 manner as in Example 1, except that a protective layer-forming coating
 solution of the fluorocarbon resin as mentioned in Example 1 was directly
 coated by a knife coater so as to provide a dry coating thickness of 6
 .mu.m, as a protective layer on the phosphor layer formed on a support in
 the same manner as in Example 1, in place of the polyethylene
 terephthalate film, one side of which was provided with the fluorocarbon
 resin layer.
 TEST EXAMPLE
 With regard to the above prepared intensifying screens (1) to (4) of
 Examples 1 to 4 and the comparative intensifying screens (R1) and (R2) of
 Comparative Example, radiographic properties (sensitivity and sharpness)
 were measured by using orthochromatic films ("Super HR-S30" manufactured
 by Fuji Photo Film Co., Ltd.), and also abrasion resistance, pinhole
 resistance, anti-staining property and anti-fouling property were
 evaluated, and the results are shown in the following Table 1. The
 respective evaluation method and evaluated values are explained below.
 Sensitivity; Expressed by relative value as compared with the sensitivity
 of the intensifying screen (R1) of Comparative Example which is determined
 as 100.
 Sharpness: MTF value of each intensifying screen was measured at a spatial
 frequency of 2.0 LP/mm and sharpness was expressed by relative value as
 compared with the MTF value of the intensifying screen (R1) of Comparative
 Example which is determined as 100.
 Abrasion resistance: Abrasion state on the surface of an intensifying
 screen was relatively evaluated by stroking an intensifying screen of 5
 cm.times.5 cm square loaded with 100 g to and from at a distance of 25 cm
 for 5,000 times on an orthochromatic film ("Super HRS30" manufactured by
 Fuji Photo Film Co., Ltd.) placed on a smooth plate.
 Pinhole resistance: An abrasive paper ("CC-320-CW" manufactured by Sankyo
 Rikagaku Kabushiki Kaisha) of 5 cm.times.15 cm was placed on the surface
 of an intensifying screen of the same size, and a load of 1 kg was applied
 thereon by rolling a rubber roller to cause pinholes. Thereafter, a
 penetrating solution ("Super check" manufactured by Tokushu Toryo
 Kabushiki Kaisha) was sprayed thereon and was quickly wiped off with a
 gauge impregnated with ethanol. The pinhole parts are colored due to the
 penetration of the penetrating solution, and pinhole resistance was
 relatively evaluated by the degree of coloring due to the penetration of
 the penetrating solution.
 Anti-staining property: a penetrating solution ("Super Check" manufactured
 by Tokushu Toryo Kabushiki Kaisha) was sprayed on the surface of an
 intensifying screen, and the intensifying screen was allowed to stand for
 1 minute and a colored degree was evaluated after wiping off the
 penetrating solution with a gauze impregnated with ethanol.
 Anti-fouling property: A line was drawn on the surface of an intensifying
 screen by "DERMATOGRAPH" manufactured by Mitsubishi Empitsu Company and
 the drawn line was wiped off with a dry gauze to evaluate wiping-off
 property.
 Evaluation results of abrasion resistance, pinhole resistance,
 anti-staining property and anti-fouling property are shown in the
 following Table 1.
 TABLE 1
 Anti- Anti-
 Intensifying Radiographic properties Abrasion Pinhole staining
 fouling
 screen Sensitivity Sharpness resistance resistance property
 property
 (1) 102 100 .largecircle. .largecircle.
 .largecircle. .circleincircle.
 (2) 102 100 .largecircle. .largecircle.
 .largecircle. .circleincircle.
 (3) 102 100 .largecircle. .largecircle.
 .largecircle. .largecircle.
 (4) 102 100 .largecircle. .largecircle.
 .largecircle. .largecircle.
 (R1) 100 100 .largecircle. .DELTA.
 .largecircle. .DELTA.
 (R2) 103 97 .DELTA. .largecircle. .DELTA.
 .circleincircle.
 .circleincircle.: Excellent, .largecircle.: Good, .DELTA.: Poor
 As evident from the data in Table 1, the intensifying screens (1) to (4) of
 the present invention had radiographic properties at the same or higher
 level and more satisfactory pinhole resistance and anti-fouling property
 as compared with the comparative intensifying screen (R1), and also had
 radiographic properties at the same or higher level and more satisfactory
 abrasion resistance and anti-staining property as compared with the
 comparative intensifying screen (R2).
 Also, the intensifying screens (1) to (4) of the present invention had
 conveying properties of an X-ray film, intimate contact properties with an
 X-ray film and releasing properties at the same level as compared with the
 comparative intensifying screen (R2), but these properties were more
 satisfactory as compared with the comparative intensifying screen (R1).
 As mentioned above, the present invention provides an intensifying screen
 having a satisfactory radiographic image quality and also having excellent
 durability, anti-staining property and anti-fouling property, which is
 more improved in respect of conveying property of an X-ray film, intimate
 contact with an X-ray film and releasing property, as compared with
 conventional intensifying screens.