JPH02278196A - Radiation image conversion panel and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable manufacturing a radiation image conversion panel having a high packing of a fluorescent body and a high sensitivity by applying a surface treatment to sitmulated phosphorescent particles in a fluorescent layer, by use of a coupling agent of a titanate series. CONSTITUTION:A coupling agent of a titanate series has a function to loosen aggregation by forming an organic monomolecular film on an inorganic surface, to distribute fluorescent particles homogeneously. As this sort of a coupling agent, it is preferable to use a light yellow liquid solvent such as a tetraoctyl bis (ditridecyl phosphite) titanate and the like. A surface treatment method is appropriately selected from already known methods such as a dry direct treatment, according to the fluorescent body and the solvent to be used. In this way, a fluorescent sheet consisting of a surface-treated fluorescent body and a binder is produced, and the sheet is placed on a carrier body. At the same time, the sheet is compressed at a temperature higher than a softening temperature or a melting point of the binder. This process can raise the packing of the fluorescent body while suppressing decrease of the sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a radiation image conversion panel used in a radiation image conversion method using a stimulable phosphor and a method for manufacturing the same.

[Technical Background of the Invention and Prior Art] As an alternative to conventional radiography, there is a radiation image conversion method using a stimulable phosphor as described in, for example, Japanese Unexamined Patent Publication No. 55-12145. Are known.

This method uses a radiation image conversion panel (also called a stimulable phosphor sheet) containing a photostimulable phosphor, and converts the radiation transmitted through or emitted from the object into a radiation image conversion panel containing a photostimulable phosphor. The stimulable phosphor is absorbed by the phosphor, and then exposed to electromagnetic waves (excitation light) such as visible light and infrared rays.
By excitation in a time series with
This fluorescence is read photoelectrically and an electric charge of 1 is emitted.
No. 3 is obtained, and the radiation image of the subject or subject is reproduced as a visible image based on the obtained electrical signals.

According to this radiation image conversion method, it is possible to obtain a radiation image rich in information with a much smaller radiation exposure of 5 seconds compared to the conventional radiography method that uses a combination of a radiographic film and an intensifying screen. It has the advantage of being able to do this.

Therefore, this method has very high utility value especially in direct medical radiography such as X-ray photography for the purpose of medical diagnosis.

The radiation image conversion panel used in the radiation image conversion method is
The basic structure consists of a support and a stimulable phosphor layer provided on one side of the support.

Note that a support is not necessarily required when the phosphor layer is self-supporting. In addition, a transparent protective film is generally provided on the surface of the stimulable phosphor layer opposite to the support (the surface facing the support and not exposed to carbon), and the phosphor layer is chemically protected from the phosphor layer. protection from physical deterioration or physical impact.

The stimulable phosphor layer generally consists of a stimulable phosphor and a binder that contains and supports the stimulable phosphor in a dispersed state.The stimulable phosphor absorbs radiation such as XIQ and then is irradiated with excitation light. It has the property of exhibiting stimulated luminescence when exposed to light.

Therefore, the radiation transmitted through the subject or emitted from the subject is absorbed by the stimulable phosphor layer of the radiation image conversion panel in proportion to the radiation dose, and the radiation image of the subject or subject is displayed on the panel. It is formed as an image of accumulated energy. This accumulated image can be emitted as stimulated luminescence light by irradiating the excitation light, and by photoelectrically reading this stimulated luminescence light and converting it into an electrical signal, the accumulated image of radiation energy can be visualized. It becomes possible to do so.

The radiation image conversion method is a very advantageous image forming method as mentioned above, but the radiation image conversion panel used in this method is similar to the intensifying screen used in conventional radiography.
It is desired that the image quality is high and provides an image with good image quality (sharpness, graininess, etc.).

The sensitivity of a radiation image conversion panel basically depends on the total amount of stimulated luminescence of the stimulable phosphors contained in the panel, and this total amount of luminescence depends not only on the luminance of the phosphors themselves but also on the fluorescence It also varies depending on the content of phosphor in the body layer. A high content of phosphor also means high absorption of radiation such as X-rays, resulting in higher sensitivity and at the same time improved image quality (particularly graininess). on the other hand,
When the content of phosphor in the phosphor layer is constant, the more densely packed the phosphor particles are, the thinner the layer thickness can be, which can reduce the spread of excitation light due to scattering. It is possible to obtain relatively high sharpness.

The present applicant has developed a radiation image conversion panel that has a phosphor layer densely packed with 5 phosphors, and has a radiation image conversion panel in which the porosity of the phosphor layer is reduced by compressing the phosphor layer. We have already applied for a panel and its manufacturing method (
JP-A-59-126299, JP-A-59-126
(Refer to the 300th bulletin).

In the radiation image conversion panel described above, the density of the phosphor in the phosphor layer was made higher than that of the 1,000-wafer radiation image conversion panel by compressing the phosphor layer. the result,
Although this radiation image conversion panel had excellent sharpness, on the other hand, there was a problem in that the sensitivity was low due to the phosphor being partially destroyed by the compression process.

[Summary of the Invention] An object of the present invention is to provide a radiation image conversion panel having a high phosphor filling rate and high sensitivity.

It is also an object of the present invention to provide a method for manufacturing a radiation image conversion panel that can increase the phosphor filling rate while suppressing a decrease in sensitivity due to compression processing.

The above object is to provide a radiation image conversion panel of the present invention substantially consisting of a support and a phosphor layer provided on the support and comprising a binder and a stimulable phosphor,
A radiation image conversion panel characterized in that the stimulable phosphor particles in the phosphor layer are surface-treated with a titanate-based coupling agent, and a) the stimulable phosphor particles are subjected to titanate-based coupling. b) forming a phosphor sheet comprising a binder and the surface-treated stimulable phosphor; c) placing the phosphor sheet on a support and treating the surface with the binder; This can be achieved by a method for producing a radiation image storage panel, comprising the step of adhering the phosphor sheet onto a support while compressing it at a temperature equal to or higher than the softening temperature or melting point of the phosphor sheet.

Titanate coupling agents differ from silane coupling agents in that they are single-shot organic substances on the inorganic surface. -By forming a film, it loosens the agglomeration and uniformly disperses the phosphor particles, which improves the adhesion between inorganic and organic materials and improves processability.

In the radiation image conversion panel of the present invention, the surface of the stimulable phosphor particles is surface-treated with the above titanate coupling agent and then pressure-treated to increase the filling rate of the phosphor. The phosphor is compressed in a state in which the particles are uniformly dispersed and the affinity between the phosphor surface and the binder resin is improved. Therefore, it is possible to prevent the phosphor particles from destroying each other to a large extent due to compression. Moreover, in the method of manufacturing the radiation image storage panel of the present invention, a phosphor sheet consisting of a phosphor and a binder is made in advance, and this phosphor sheet is placed on a support to adjust the softening temperature or melting point of the binder. Since compression is performed at the same time as the installation on the support plate, damage to the phosphor can be largely prevented.

In other words, during compression, the phosphor crystals dispersed in a binder heated to a temperature above the softening or melting point are subjected to pressure with a certain degree of freedom. can be oriented. Moreover, pressure is applied without fixing the phosphor sheet to the support,
Since the phosphor sheet is placed on the support without being compressed, the pressure applied to the phosphor sheet acts to orient the phosphor crystals, while at the same time applying pressure that would destroy the crystals if the phosphor sheet were fixed. But it moves like stretching the sheet thinly and spreading it out.

Preferred embodiments of the present invention are listed below.

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

(2) The binder has a softening temperature or melting point of 30 to 30
A radiation image conversion panel characterized in that it is a thermoplastic elastomer having a temperature of 0°C.

(3) The binder has a softening temperature or melting point of 30 to 20
A radiation image conversion panel characterized in that it is a thermal IIT plastic elastomer having a temperature of 0°C.

(4) The binder has a softening temperature or melting point of 30 to 15
A radiation image conversion panel characterized in that it is a thermoplastic elastomer having a temperature of 0°C.

(5) A radiation image storage panel, wherein the titanate coupling agent mentioned in item (1) is a pale yellow liquid.

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

(7) 1. The binder has a softening temperature of 2 or a melting point of 30 to
A method for producing a radiation image storage panel, characterized in that it is made of a thermoplastic elastomer having a temperature of 300°C.

(8) The binder has a softening temperature or melting point of 30 to 20
A method for producing a radiation image storage panel, characterized in that the panel is made of a thermoplastic elastomer having a temperature of 0°C.

(9) The binder described in h has a softening degree of 6V or a melting point of 3
A method for producing a radiation image storage panel, characterized in that it is a thermoplastic elastomer having a temperature of 0 to 150°C.

(10)-1 = A method for producing a radiation image storage panel, wherein the titanate coupling material is a pale yellow liquid.

(11) A method for producing a radiation image storage panel, which comprises providing an adhesive layer and/or a light reflecting layer on a support in advance, prior to step C).

(12) A method for producing a radiation image conversion panel, characterized in that the compression in (h) column C) is performed using five calendar rolls.

(13) The compression in step C) above is 50Kgw/
A method for manufacturing a radiation image conversion panel, characterized in that the manufacturing method is carried out at a pressure of cm2 or more.

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

The method for producing a radiation image storage panel of the present invention comprises: a) surface-treating stimulable phosphor particles with a titanate coupling agent; b) a binder and the surface-treated stimulable phosphor. forming a phosphor sheet, C) placing the phosphor sheet on a support and adhering the phosphor sheet onto the support while compressing at a temperature of -F above the softening temperature or melting point of the binder; The process consists of.

First, step a) will be described.

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

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

As mentioned above, a stimulable phosphor is a phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light.
From a practical standpoint, it is desirable that the phosphor be a phosphor that exhibits stimulated luminescence in the wavelength range of 300 to 500 nm when excited by excitation light in the wavelength range of 400 to 900 nm. As an example of the stimulable phosphor used in the radiation image conversion panel of the present invention, Ba
SO4: AX and SrSO4 described in JP-A-48-80489; phosphor represented by AX; Li2 described in JP-A-53-39277;
B4O7: Cu, Ag, Li2 described in JP-A No. 54-47883
C1(B202) N: Cu and Li2O・(B2
02) X: Cu, Ag, US Patent No. 3.859,
SrS described in No. 527: Ce, Sm,
SrS:Eu.

Sm, Th02:Er, and La2O2S:Eu,
Sm, ZnS described in JP-A-55-12142
:Cu, Pb, Ba0-xAff203 :Eu (however, 0.8≦X≦10), and M'O xsi02
:A (j: Dashi, M ” HaM g, Ca, Sr,
Zn, Cd, or Ba, and A is Ce, Tb, Eu
, Tm, Pb, TfL, Bi, or Mn, and X is 0.5≦X≦2.5), as described in JP-A-55-12143 (Ba
t-1-? + Mgx, Cay) FX: aEu" (T, X is at least one of C2 and Br, X and y are 0, , 10-6≦a≦5xlO"), LnO described in JP-A-55-12144
X: xA (Ln is at least one of La, Y, Gd, and Lu, X is Cfl and Br
A is at least one of Ce and Tb, and X is 0<x<0.1), as described in JP-A-55-12145 (B
a l-11, M''X) FX: yA
(However, M2◆ is at least one of Mg, Ca, Sr, Zn, and CD, X is at least one of C1, Br, and ■, A is Eu, Tb, Ce,
Tm, Dy, Pr, Ho, Nd, Yb, and E
At least one of r, especially X, satisfies 0≦X≦0.
6, y is 0≦y≦0.2), Ba described in JP-A-55-843897
FX: Phosphor expressed by xCe, yA JP-A-1983-
M”FX-xA described in Publication No. 160078:
yLn [However, Ml is Ba, Ca, Sr, Mg, Z
n, and at least one of Cd is 4Ti, A is Be
d, MgO1CaO, 5rO1Bad, ZnO, Au2
01, Y2O1, La20), In20), 5i02,
TiO2, ZrO2, GeO2, 5n02, Nb2O6
, Ta205', and ThO2, and Ln is Eu, Tb, Ce, or Tm.

Dy, Pr, Ho, Nd, Yb, Er, S
m, and at least one of Gd, X is C2, B
r, and at least one of I, and X and y are respectively 5X10-"≦X≦0.5, and o<y
≦0.2] is a phosphor represented by the composition formula (
Ba+-x 1M ” 11) F 2 ・a B
a X 2 :yEu, zA [However, Ml is beryllium, magnesium, calcium, strontium,
at least one of 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 each 0.5 ≦a≦
1.25.0≦X≦1.10-6≦y≦2X10-',
and 0<z≦10-2] (Ba, -1, M' 1)F 2 ・aBaX 2
:yEu, zB [where M' is at least one of beryllium, magnesium, calcium, strontium, sub-29, and cadmium, X is at least one of chlorine, bromine, and iodine, a, x,
y, and 2 are each 0.5≦a≦1.25.0≦X
≦1.10-6≦y≦2×10-゛ and 0<z≦2
A phosphor represented by the compositional formula of
+-x9M厘g)F2-aBaX2yEu,zA [However, Ml is beryllium, magnesium, calcium,
At least one of strontium, zinc, and cadmium, 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 0. .5≦a
≦1.25.0≦X≦1.10-6≦y≦2×io-'
, and a phosphor represented by the composition formula O<z≦5xio-', M"O, which is not described in JP-A-58-69281.
X: xCe [However, M” is Pr, NdPm,
Sm, Eu, Tb, Dy, Ho,
is at least one trivalent metal selected from the group consisting of Er, Tm, Yb, and Bi, and X is C2 and B
one or both of r, and X is O<x<0.1] A phosphor B described in JP-A-58-206678
a+−xMx/2LX/2FX:
y E u” [Tatashi, M is Li, Na, R
b, and represents at least one alkali metal selected from the group consisting of Cs; L represents Sc, Y, La, Ce;
, Pr, Nd, Pm, Sm, Gd, Tb, Dy.

Ho, Er, Tm, Yb, Lu, A! , Ga, In, and Tn; X represents at least one halogen selected from the group consisting of C2, Br, and I; and X is 10-2 ≦X≦0.5, y is o<y≦0.1 A phosphor represented by the following composition formula, BaF described in JP-A-59-27980
X-xA: yEu” [However, X is Cf2, B
r, and at least one kind of halogen selected from the group consisting of ■; A is a fired product of a tetrafluoroboric acid compound; and X is 10-'≦X≦0.1, y
is a phosphor represented by the composition formula where o<y≦0.1,
M3(P 04)z・N X2:yA, M3(P 0
4) z: yA and nReX, mAX'2: xEu
, nReX, ・mAX'2: xEu, ySm, M'
X -aM"X'・b M"'
X is Cf1. Br, and at least one halogen selected from the group consisting of I; A is from the hexafluoro compound group consisting of monovalent or divalent metal salts of hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid; is a fired product of at least one selected compound; and X is 10-6≦X≦0
．． 1, y is o<y≦0.1] A phosphor represented by the composition formula BaFX-xNaX':aEu'' [where X
and Xo are each at least one of C1, Br, and I, and X and a are each 0<x≦
2, and Ova≦0.2], M”F described in JP-A No. 59-56480
X−xNaX′:yEu”:zA [However, Ml is
is at least one alkaline earth metal selected from the group consisting of Ba, Sr, and Ca; X and Xo are
each is at least one kind of halogen selected from the group consisting of Cf2, Br, and I; A is V, Cr,
is at least one transition metal selected from Mn, FeCo, and Ni; and X is O<x≦2. y is o<y≦0.2, and Z is 0<z≦10-2]
A phosphor represented by the composition formula M' described in JP-A-59-75200
FX -aM 'X'・bM' Seal x”2c
M"X"') ・xA: yEu" [However, Ml
is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr, and Ca, and M1 is Li
, Na, Rb, and Cs; Mo 1 is Be
and at least one divalent metal selected from the group consisting of Mg; Mn is A! , Ga, In, and Tfl
at least one trivalent metal selected from the group consisting of; A is a metal oxide; X is Ca, Br, and I;
X', X'', and xl are at least one halogen selected from the group consisting of F, CI, Br, and ■; and a is 0≦ a≦2, b is 0≦b≦10, C is 0≦C≦1o-2 and a+b+c≧10-6: X is O< x≦0.5, y is o<y≦0.2 A phosphor represented by the composition formula of
X2- aM"
o is at least one halogen selected from the group consisting of Cfl, Br and ■, and X≠X';
and a is 0.1≦a≦100, and X is O<x≦0.2].
FX-aM'X':xEu" [However, M
l is at least one kind of alkaline earth metal selected from the group consisting of Ba, Sr and Ca; Ml is at least one kind of alkali metal selected from the group consisting of Rb and Cs; and at least one species of halogen selected from the group consisting of I: X° is F
is at least one halogen selected from the group consisting of , CR5Br, and Phosphor, M'X described in JP-A No. 62-25189
:xBi [where Ml is at least one alkali metal selected from the group consisting of Rb and C5;
is at least one kind of halogen selected from the group consisting of C2, Br and I; and X is a numerical value in the range of O<x≦0.2. can be mentioned.

In addition, the M"X2 .aM'X' 2 :xEu" stimulable phosphor described in the above-mentioned Japanese Patent Application Laid-Open No. 60-84381 contains additives as shown below.
"X' may be contained in a proportion below per 2t mole.

bM described in JP-A-60-166379
'X'' (However, Ml is at least one alkali metal selected from the group consisting of Rb and Cs, and
is at least one kind of halogen selected from the group consisting of F, CR1Br and ■, and b is o<b≦10
．． 0); bKX"-cMgX"2 and dM"X"1 described in JP-A No. 60-221483
(However, Mll is Sc, Y, La, Gd and Lu
is at least one trivalent metal selected from the group consisting of
and at least one kind of halogen selected from the group consisting of I, and s, c and d are each 0≦b
≦2.0.0≦C≦2゜0.0≦d≦2.0,
and 2 X 10-'≦b0c+d);
yB described in Publication No. 0-228592 (y is 2x t o-'≦y≦2xlO-');
bA(
However, A is at least one kind of oxide selected from the group consisting of 5i02 and P2O, and b is 10
-4≦b≦2xlO-'); JP-A-61-120
bSin described in Publication No. 883 (however, b is o<b≦3 x 10-'); JP-A-61-12
As described in Publication No. 0885,
(However, x" is at least one kind of halogen selected from the group consisting of F, Cf1.Br, and ■, and b satisfies o<b≦10-3.)
bCsX''-cSnX described in Publication No. 86
"2 (X" and X"° are respectively F and CIL
, Br and I, and b and C each satisfy o<b
≦10.0 and 10-6≦C≦2×10-2)
: and bCsX''·yLn' described in JP-A No. 61-235487.

(x” is at least one kind of halogen selected from the group consisting of F, Cl, Br and I, and Ln is S
c, Y, Ce, Pr, Nd, Sm.

Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu
at least one rare earth element selected from the group consisting of, and b and y are respectively o<b≦10.0
and 10-6≦y≦1.8x 10-').

Among the stimulable phosphors listed in item 1-1, divalent europium-activated alkaline earth metal halide phosphors and cerium-activated rare earth oxyhalide phosphors are particularly preferred because they exhibit high-intensity stimulated luminescence. However, the stimulable phosphor used in the present invention is not limited to the phosphors mentioned above, but any phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light can be used. A stimulable phosphor of any kind with a margin of 1° or less is surface-treated with a titanate coupling agent.

Titanate-based coupling agents have +T between the group that provides affinity with the resin or the group that reacts with the resin and the parent group. By forming quasi-molecules of high quality, it dissolves aggregation and uniformly disperses fine particles, which in turn has the function of adhering organic and inorganic substances well and increasing T-ability. Examples of such titanate coupling agents include tetraoctyl bis(di-tridecyl phosphite) titanate, his(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, and isopropyl pyrophosphate. trioctanoyl titanate, isopropyl dimethacrylic isostearoyl titanate, isopropyl triisostearoyl titanate, isopropyl tris(N-aminoethyl-aminoethyl) titanate, tetra(2,2-sialyloxymethyl-1 −
butyl)bis(di-tridecyl)phosphite thianate, isopropyl tridodecylbenzene sulfonyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tri(dioctylphosphate) titanate, isopropyl tricumylphenyl titanate, Examples include tetraisopropyl bis(dioctyl phosphite) and titanate. Among these, tetraoctyl bis(
Pale yellow liquid titanate coupling agents such as di-tridecyl phosphite) titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, and bis(dioctyl pyrophosphate) ethylene titanate have a color that is similar to that of the excitation light. This is preferable because there is no fear of adversely affecting the light emission.

Surface treatment methods include conventionally known treatment methods such as dry direct treatment, solvent treatment, and water slurry treatment.
It can be selected as appropriate depending on the phosphor and coupling agent.

Next, the step b) will be explained.

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

As the binder, a thermoplastic elastomer that is elastic at room temperature and becomes fluid when heated is preferably used. Examples of thermoplastic elastomers include polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, ethylene vinyl acetate,
Polyvinyl chloride, natural rubber, fluororubber, polyisoprene, chlorinated polyethylene, styrene-butadiene rubber,
Examples include silicone rubber.

Among the above thermoplastic elastomers, those having a softening temperature or melting point of 30°C to 300°C are generally used, or those having a softening temperature or melting point of 30°C to 200°C are preferable, and 30°C to 15°C.
It is more preferable to use one at 0°C.

Examples of solvents for preparing coating solutions include lower alcohols such as methanol, ethanol, n-propanol, and n-butanol; chlorine-containing hydrocarbons such as methylene chloride and ethylene chloride; acetone, methyl ethyl ketone, and methyl isobutyl ketone. Ketones; esters of lower fatty acids and lower alcohols such as methyl acetate, ethyl acetate, and butyl acetate; ethers such as dioxane, ethylene glycol monoethyl ether, and ethylene glycol methyl 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 phosphor, etc., but generally the mixing ratio of the binder and the stimulable phosphor is 1. :l to 1:100 (weight ratio), and particularly preferably from l:8 to 1:40 (weight ratio).

The coating liquid also contains a dispersant to improve the dispersibility of the phosphor in the coating liquid, and a dispersant to improve the bonding force between the binder and the phosphor in the phosphor layer after formation. Various additives such as plasticizers may also be mixed. Examples of dispersants used for such purposes include phthalic acid, stearic acid, caproic acid, lipophilic surfactants, and the like. Examples of plasticizers include phosphate esters such as triphenyl phosphate, tricresyl phosphate, and diphenyl phosphate; phthalate esters such as diethyl phthalate and dimethoxyethyl phthalate; ethyl phthalyl ethyl glycolate, butyl phthalyl glycolate; Polyesters of polyethylene glycol and aliphatic dibasic acids, such as polyesters of triethylene glycol and adipic acid and polyesters of diethylene glycol and succinic acid.

T containing the phosphor and binder prepared as described above
A coating film of the coating liquid is formed by first uniformly applying the coating TFI liquid to the surface of a temporary support for forming a sheet. This coating operation can be carried out using conventional coating means such as a doctor blade, roll coater, knife coater, etc.

Temporary supports include, for example, glass, metal plates, various materials used as supports for intensifying screens in conventional radiography, or supports for radiation image conversion panels. It can be arbitrarily selected from materials known as . Examples of such materials include:
Films of plastic materials such as cellulose acetate, polyester, polyethylene terephthalate, polyamide, polyimide, triacetate, polycarbonate, metal sheets such as aluminum foil, aluminum alloy foil, ordinary paper, baryta paper, resin coated paper, pigments such as titanium dioxide, etc. Examples include pigment paper containing pigment, paper sized with polyvinyl alcohol, plates or sheets of ceramics such as alumina, zirconia, magnesia, and titania.

A coating solution for forming a phosphor layer is applied to a temporary support, and after drying, it is peeled off from the temporary support to form a phosphor sheet that will become a phosphor layer of a radiation image conversion panel.

Therefore, it is preferable to apply a release agent to the surface of the temporary support in advance so that the formed phosphor sheet can be easily peeled off from the temporary support.

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

First, a support for a radiation image conversion panel is prepared separately from the phosphor sheet formed as described above.

This support can be arbitrarily selected from the same materials as the temporary support used when forming the phosphor sheet.

In known radiation image conversion panels, a phosphor layer is provided in order to strengthen the bond between the support and the phosphor layer, or to improve the sensitivity or image quality (sharpness, granularity) of the radiation image conversion panel. A polymeric substance such as gelatin is coated on the surface of the side support to form an adhesion imparting layer, or a light reflective layer made of a light reflective substance such as titanium oxide, or a light absorbing substance such as carbon black. It is known to provide an absorbent layer or the like. The support used in the present invention can also be provided with these various layers, and their configurations can be arbitrarily selected depending on the purpose, use, etc. of the desired radiation image storage panel.

Furthermore, as described in JP-A-58-200200, in order to improve the sharpness of the obtained image, the surface of the support on the phosphor layer side (the surface of the support on the phosphor layer side) When an adhesion-imparting layer, a light-reflecting layer, a light-absorbing layer, etc. are provided, minute irregularities may be formed on the surface (meaning the surface thereof).

The phosphor sheet obtained in step b) is placed on a support 1- and adhered onto the support while being compressed at a temperature higher than the softening temperature or melting point of the binder.

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

The pressure during compression is generally 50 kgw/cm2 or more.

The porosity of the phosphor layer formed on the support as described above can be theoretically determined by the following equation (1).

Below margin Vair/V= (a+b) ρ x ρ yV-A (apy+
bpx) Vair/V= (a+b)px p yV-A (apy+ bp
x) V[(a+b) ρ x ρ y−a p y
air] (V: total volume of the phosphor layer Vair: volume of air in the phosphor layer A: total weight of the phosphor layer ρX: density of the phosphor, ρ: density of the binder ρair: Density of air a: Weight of phosphor b = Weight of binder) Furthermore, in equation (I), pair is approximately 0, so equation (1) can be approximately expressed by equation (II) below. be able to.

Below margin V [(a+b)ρXρ,] (II) (Tap, V, Vair, A, 9x, /:)y,
The definitions of a and b are the same as in formula (I).) In the present invention, the porosity of the phosphor layer was calculated using formula (II).

Further, the filling rate of the phosphor can be determined by the following equation (III).

Aaρy ■[(a+b)pxρ y] --(III) (However, V, Vair, A, pz, ρ7,
The definitions of a and b are the same as in formula (I)) In a normal radiation image conversion panel, a phosphor layer is placed on the surface of the phosphor layer on the side opposite to the side in contact with the support as described above. A transparent protective film is provided to provide physical and chemical protection. Such a transparent protective film is preferably provided also in the radiation image conversion panel according to the present invention.

The transparent protective film may be made of a transparent material such as a cellulose derivative such as cellulose acetate or nitrocellulose; or a synthetic polymer material such as polymethyl methacrylate, polyvinyl butyral, polyvinyl formal, polycarbonate, polyvinyl acetate, or vinyl chloride/vinyl acetate copolymer. It can be formed by coating the surface of the phosphor layer with a solution prepared by dissolving a polymeric substance in an appropriate solvent. Alternatively, plastic sheets made of polyethylene terephthalate, polyethylene naphthalate, polyethylene, polyvinylidene chloride, polyamide, etc.
; Alternatively, a protective film-forming sheet such as a transparent glass plate may be formed separately and adhered to the surface of the phosphor layer using a suitable adhesive.

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

Furthermore, for the purpose of improving the sharpness of the obtained image, a colored layer that absorbs excitation light but does not absorb stimulated emission light may be added to at least one of the above layers (Japanese Patent Publication No. 59-23400 (see issue).

Next, examples of the present invention will be described. However, the present invention is not limited to each of the examples.

[Example 1] Phosphor: l1aFBr09101: lmiu”10
Disperse 0 g in 50 g of solvent = 2-propatool,
Here, 0.25 g of ditanate-based coupling reduction (tetraoctylhis (di-tridecyl phosphite) titanate [Blenaku 1-KR46B manufactured by Ajinomoto @ Co., Ltd.]
．． 5 wt, %) was added. This was mixed in a roller mill for 4 hours, classified, and then dried under reduced pressure at 150°C.

Next, as a coating liquid for forming a phosphor sheet, 100 g of the phosphor treated as described in L. Binder: Polyurethane (Sumitomo Bayer Urethane Desmolac TPKL-5-
2625 [solid content 40%])・22.5g Anti-yellowing agent:
Bisphenol A type epoxy resin・・・1.0
g was added to a 1:1 mixed solvent of methyl ethyl ketone and 2-propertool and dispersed using a propeller mixer to prepare a coating solution with a viscosity of 30 PS (25°C) (binder/phosphor ratio = 1/20). . This was applied onto polyethylene terephthalate (temporary support, thickness 180 μm) coated with a silicone mold release agent, dried, and then peeled off from the temporary support to form a phosphor sheet.

On the other hand, as a coating liquid for forming a light reflective layer, BaFBr (particles with a diameter in the range of 1 to 5 μm)
% content)...214g Soft acrylic resin solid content...25.7g Epoxy resin...
...10.7g nitrocellulose (nitrification degree 11.
5%, solid content 10% by weight)...64g was added to methyl ethyl ketone and dispersed with a propeller mixer to prepare a dispersion having a viscosity of 25 to 35 PS (25°C).

Separately, as a coating liquid for forming an undercoat layer, 90 g of soft acrylic resin solids and 50 g of nitrocellulose were added to methyl ethyl ketone and dispersed and mixed. The viscosity is 3 to 6 PS (
25°C) was prepared.

A polyethylene terephthalate (support) with a thickness of 300 μm was placed horizontally on a glass plate, and the coating solution for forming an undercoat layer described in -J2 was uniformly applied onto the support using a doctor blade. The coating film was dried by gradually increasing the temperature to 715 μm in thickness to form an undercoat layer on the support. Further, the above-mentioned coating solution for forming a light-reflecting layer was coated (coating film thickness: 60 μm) and dried in the same manner to form an undercoat layer and a light-reflecting layer on the support. The previously prepared phosphor sheet was placed on top of this and compressed.

Compression was done using calender rolls at 400K g w.
It was carried out continuously at a pressure of / cm 2 and a temperature of 80 °C. Due to this compression, the phosphor sheet and the light reflecting layer of the support were completely fused together.

After this compression, a transparent protection +V was formed by adhering a polyethylene terephthalate transparent film (10 μm thick) coated with a polyester adhesive on one side with the adhesive side facing down.

A radiation image storage panel consisting of a support, an undercoat layer, a light reflection layer, a phosphor layer, and a transparent protective film was manufactured as described in 1-1 below.

[Comparative Example 1] In Example 1, instead of the titanate coupling agent, a silane coupling agent: γ-,crisitoxyprobyltrimethoxysilane (KBM40 manufactured by Shin-Etsu Chemical Co., Ltd., X■) was used.
3) A radiation image conversion panel comprising a support, an undercoat layer, a light reflection layer, a phosphor layer, and a transparent protective film was produced in the same manner as in Example 1 except that 0.25 g was used.

[Comparative Example 2] A radioactive material was prepared in the same manner as in Example 1 except that the surface treatment of the phosphor was not carried out, and was composed of a support, an undercoat layer, a light reflection layer, a phosphor layer, and a transparent protective film. An image conversion panel was manufactured.

In the panel: The phosphor filling rate in the phosphor layer of each of the radiation image conversion panels of Examples and Comparative Examples manufactured as described above was determined as (I
II) It was determined by the formula. However, the density of the phosphor is 5
．． 1g/cm', and the density of the binder is 1.14g/C
It was set as m'.

In addition, the tube voltage of 80 Vp is applied to each of the above radiation image conversion panels.
After irradiating with X-rays, He-Ne laser light (wavelength +
632.8 nm), and the amount of stimulated luminescence of each panel was measured.

The results are shown in Table 1.

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

The following margins are as follows: Stimulated luminescence amount Phosphor filling rate (%) Example 1 107 73.4 Comparative example 1
100 70.6 Comparative Example 2 98
70.5 As is clear from Table 1, the radiation image conversion panel of the present invention has a high phosphor filling rate and a high amount of stimulated luminescence. It is also seen that the method for manufacturing a radiation image conversion panel of the present invention can increase the phosphor filling rate while suppressing the decrease in sensitivity due to compression processing.

Patent applicant Fuji Photo Film Co., Ltd. Agent Patent attorney Yasuo Yanagawa

Claims (2)

[Claims] 1. A radiation image conversion panel substantially constituted by a support and a phosphor layer provided on the support and comprising a binder and a stimulable phosphor, wherein the stimulable phosphor in the phosphor layer 1. A radiation image conversion panel characterized in that the surface of the fluorescent phosphor particles is treated with a titanate coupling agent. 2. a) a step of surface treating the photostimulable phosphor particles with a titanate coupling agent; b) a step of forming a phosphor sheet comprising a binder and the surface-treated stimulable phosphor; c) a step of treating the stimulable phosphor particles with the stimulable phosphor. A radiation image conversion panel characterized in that the phosphor sheet is placed on a support and the phosphor sheet is adhered onto the support while being compressed at a temperature higher than the softening temperature or melting point of the binder. Manufacturing method.