JP2001081385A - Radiation-shielding ink and printing thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an inexpensive, harmless radiation-shielding ink having a high-degree radiation-shielding ability, and good printability, and further to provide a printing method thereof. SOLUTION: This radiation-shielding ink is obtained by kneading 100 pts.wt. tungsten fine powder having 0.5-0.6 μm particle size with 10 pts.wt. polyester resin and 40 pts.wt. solvent. When a letter having 100 μm thickness is printed on a PET film by using the ink, and a picture is taken by X-ray through the film, the picture of the letter is superiorly clearly taken, and the scratch resistance of the printed letter on the PET film is also good.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a radiation shielding ink and a printing method thereof.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a medical tape or sheet capable of accurately confirming the positions of a puncture part and an operative part when observing the state of the inside of a human body by X-ray photography (Japanese Patent Laid-Open No. Hei 10 (1998)).
-290797). This medical tape or sheet has a configuration in which an adhesive layer is provided on one surface of the tape or sheet, and a scale for measurement is provided on the other surface. The tape or sheet has X-ray transparency, and the scale is printed with an X-ray opaque ink. Therefore, this medical tape or sheet is stuck on the human body and X
If a radiograph is taken, a scale is photographed together with the human body image in the developed X-ray photograph, and by observing the X-ray photograph, the position of the surgical site can be accurately recognized.

[0003]

The inks for printing the radiopaque scales include Al, Cu, and C.
The above-mentioned patent publications include those containing a simple substance such as a, Zn, Ag, Au, Ba, Pb, and Pt, alloys, and salt powders. The content of these powders in the ink is 5
It is said that the content is preferably about 20 to 20% by weight.

[0004] However, these inks have cost disadvantages due to the use of expensive metals such as platinum, or have safety problems due to the use of harmful metals such as lead. Furthermore, the effect of shielding radiation is small, so that it is not possible to obtain an X-ray photograph whose scale is clearly taken.

Accordingly, it is an object of the present invention to provide a radiation shielding ink having a high radiation shielding ability without the above-mentioned drawbacks and having good printability, and a printing method thereof.

[0006]

The ink of the present invention is a radiation shielding ink containing 15 to 5 parts by weight of a resin component and a solvent per 100 parts by weight of fine tungsten powder.

The particle size of the tungsten fine powder is preferably 0.9 to 0.4 μm, more preferably 0.6 to 0.4 μm.
0.5 μm. In the present invention, since the close packing property of the tungsten fine powder plays an important role, the particle size distribution is preferably narrow. Further, it is preferable to improve the filling property of the powder by adding a small amount of extremely fine particles such as irisole.

The amount of the binder resin contained in the ink of the present invention is 1 to 100 parts by weight of the tungsten fine powder.
It must be 5 to 5 parts by weight. It is not common to use such a small amount of binder resin for the tungsten fine powder as a filler, but it is an important factor in the present invention. When the amount of the resin is large, the radiation shielding property of the ink is inferior, and when the amount of the resin is small, the printability and the resistance of the printed matter are inferior. Also, as the binder resin,
Polyester resins give good results in terms of ink printability and print resistance. The amount of solvent in the ink is
Preferably, the amount is 60 to 15 parts by weight per 100 parts by weight of the tungsten fine powder for printability and ink stability.

Further, using the ink of the present invention, a tape having a radiopaque scale, such as that described in JP-A-10-290797, is printed on a radiolucent substrate such as paper or plastic. In the case of manufacturing, a high tension screen is used, the emulsion thickness of the screen is 60 to 200 μm, and the total value of the screen thickness and the emulsion thickness is 160 to 320 μm. 60 emulsion thickness
μm and the total value of the screen thickness and the emulsion thickness is 1
If it is less than 60, the thickness of the dry layer of the printed ink layer becomes insufficient, and a reliable radiation shielding effect cannot be obtained. On the other hand, when the emulsion thickness exceeds 200 μm and the total value of the screen thickness and the emulsion thickness exceeds 320 μm, the thickness of the printed ink layer becomes excessive and ink is consumed unnecessarily, resulting in cost disadvantages.

When printing on the radiation transmitting substrate using the ink of the present invention, when using a metal mask, the thickness of the metal mask is 120 to 150 μm.
And If the thickness of the metal mask is less than 120 μm, the thickness of the dry layer of the printed ink layer becomes insufficient as described above, and a reliable radiation shielding effect cannot be obtained.
On the other hand, if the thickness of the metal mask exceeds 150 μm, the thickness of the printed ink layer becomes excessive, and ink is unnecessarily consumed as described above, resulting in a cost disadvantage.

Further, when the printing is performed, 50 to 70
It is preferable to use a durometer having a low hardness.

[0012]

EXAMPLES The radiation shielding ink of the present invention will be described below with reference to examples and comparative examples.

Embodiment 1

A radiation shielding ink was prepared by kneading 100 parts by weight of a tungsten fine powder having a particle size of 0.5 to 0.6 μm, 10 parts by weight of a polyester resin, and 40 parts by weight of a solvent. Using this ink, 100μm thick on pet film
When the characters were screen printed, the characters could be printed clearly. Also, the scratch resistance of the characters printed on the pet film was good. X-ray photography was performed through a pet film on which the characters were printed, and the X-ray photograph after development was observed. As a result, the characters were very clearly photographed.

Embodiment 2

A radiation shielding ink was prepared by kneading 100 parts by weight of tungsten fine powder having a particle size of 0.4 to 0.9 μm, 15 parts by weight of a polyester resin, and 60 parts by weight of a solvent. When characters were screen-printed on a pet film with a thickness of 100 μm using this ink, the characters could be printed clearly. Also, the scratch resistance of the characters printed on the pet film was good. An X-ray photograph was taken through a pet film on which the characters were printed, and the characters were photographed extremely clearly when the X-ray photograph was observed.

Comparative Example 1

The same procedure as in Example 1 was carried out except that tungsten fine powder having a particle size of 1.9 to 2.2 μm was used. The abrasion resistance of the characters printed on the pet film was poor. Also, the radiographic image was blurred.

Comparative Example 2

The same procedure was carried out except that 25 parts by weight of the polyester resin and 100 parts by weight of the solvent were used in the examples. The radiographic image was blurred.

[0021]

Next, an embodiment of a printing method according to the present invention will be described with reference to the drawings. FIG. 1 shows a screen printing apparatus, in which 1 is a table, 2 is a screen, 3 is a scraper, 4 is ink, and 5 is a squeegee. The screen 2 is a stainless steel mesh and has a tension of about 34.0 Newton.

As shown in FIG. 2, the thickness of the emulsion 6 fixed to the screen 2 below the screen 2 is "A1" and the thickness above the screen 2 is "A2".
A1 + A2 = 60 to 200 μm A1 + A2 + B = 160 to 320 μm where the thickness of the screen is “B”.

The ink 4 is the radiation shielding ink of the first or second embodiment, and the squeegee 5 has a low hardness of 50 to 70 durometer. The squeegee pressure is as low as about 2 kgf and the speed is as low as about 200 to 400 mm / sec.

In such a configuration, when printing is performed on a print target such as a pet film placed on the table 1 to produce a tape with a radiopaque scale, off-contact between the table 1 and the screen 2 is required. C is 3-5
Set to mm. In printing, the scraper 3 is brought into contact with the screen 2 and in a non-contact state with the squeegee 5, and is moved from the start position S to the end position E. Thereby, the ink 4 is put on the screen 2. Next, the scraper 3 is brought into contact and non-contact with the screen 2 and in contact with the squeegee 5, and is moved from the end position E to the start position S.

At this time, in the case of ordinary screen printing, printing is performed in this one reciprocating step, but in this embodiment, as described above, the squeegee pressure is low and the speed is low. Therefore, printing is not performed in this one reciprocating process, and the ink 4 is filled with the holes 7 between the emulsions 6 and 6 (FIG. 1).
See reference).

Then, again, in the same manner as described above,
Is brought into a contact state with the screen 2 and in a non-contact state with the squeegee 5, and is moved from the start position S toward the end position E. To move from the end position E to the start position S. As a result, the ink 4 is sufficiently pressed into the hole 7 and printed on the printing target.

That is, in this embodiment, printing is performed once in two reciprocating steps. Therefore, even if the value of the thickness of the emulsion 6 + the thickness of the screen 2 is large and the hole 7 is deep,
Printing can be performed without shining, and the printed film thickness can be made sufficient to obtain a radiation shielding effect. Also,
It is possible to cover the screen 2 with the ink 4 evenly, so that a three-dimensional thick printing can be obtained. Moreover, since the screen 2 is high tension, it is possible to print a clear image, and the squeegee pressure and speed are
Since the pressure is low and the speed is low, no load is applied to the screen 2.

If printing is performed once in the above two reciprocating steps, heating and drying are performed as soon as possible, for example, within about 20 minutes, thereby preventing the edge of the printed image from collapsing. can do.

When printing is started, the viscosity of the ink 4 changes due to the ambient temperature, the kneading action of the scraper 3 and the like, and the viscosity is eventually stabilized at a constant level. Therefore, it is necessary to adjust the off-contact C according to the viscosity of the ink 4 which changes and eventually becomes stable. Since the squeegee 5 is a long member extending from one end to the other end of the screen 2, the squeegee pressure is uniformly adjusted so that a uniform print film is formed over the entire length. There is a need.

In this embodiment, the case where the stainless steel mesh screen 2 is used is shown. However, a metal mask may be used. In this case, the thickness of the metal mask is set to 120 to 150 μm. Thus, the same operation and effect as the embodiment can be obtained.

[0031]

As described above, according to the radiation concealing ink of the present invention, it is inexpensive and harmless without using expensive metals and harmful metals, and has a high radiation shielding ability and good printability. Can be obtained. Further, when the particle diameter of the tungsten fine powder is 0.9 to 0.4 μm, it is possible to obtain a higher radiation shielding ability,
By including the polyester-based resin, it is possible to enhance the fixability of the ink to the printing target. Further, the amount of the solvent is adjusted to 60 to 15 per 100 parts by weight of the tungsten fine powder.
By using parts by weight, more excellent printability can be obtained. Further, according to the printed matter of the present invention, excellent scratch resistance can be obtained, and X
By performing radiography, it is possible to obtain an X-ray photograph in which prints such as graduations are clearly photographed.

According to the printing method of the present invention,
The dry ink layer thickness of the printed ink layer is not enough to provide a reliable radiation shielding effect, or the printed ink layer is too thick and the ink is not consumed unnecessarily. In addition, it is possible to perform printing that can appropriately obtain a radiation shielding effect at low cost.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a screen printing apparatus to which a printing method according to an embodiment of the present invention is applied.

FIG. 2 is a schematic enlarged sectional view of a screen.

[Explanation of symbols]

 1 table 2 screen 3 scraper 4 ink 5 squeegee 6 emulsion 7 holes

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takeshi Furumoto 808-1 Kuji, Takatsu-ku, Kawasaki-shi, Kanagawa F-term (reference) 2C035 AA06 FD01 FD19 FD42 FF22 FF26 2H114 AB11 AB15 DA02 DA04 DA56 DA64 DA77 DA80 FA01 FA10 4J004 AB01 CC02 CC05 FA09 4J039 AE06 BA06 BA36 BE01 BE12 CA07 EA36 EA43 EA45 EA48 FA02 GA10

Claims (7)

[Claims] 1. A radiation shielding ink comprising 15 to 5 parts by weight of a resin component and a solvent per 100 parts by weight of tungsten fine powder. 2. The tungsten fine powder has a particle size of 0.9.
The radiation shielding ink according to claim 1, wherein the thickness is from 0.4 to 0.4 μm. 3. The radiation shielding ink according to claim 1, wherein the resin is a polyester resin. 4. The method according to claim 1, wherein the amount of the solvent is
The radiation shielding ink according to claim 1, wherein the radiation shielding ink comprises 60 to 15 parts by weight per 0 parts by weight. 5. When printing using the radiation shielding ink according to claim 1, a high tension screen is used, the emulsion thickness of the screen is 60 to 200 μm, and the screen thickness and the emulsion are adjusted. A printing method, wherein the total thickness is 160 to 320 μm. 6. When printing using the radiation shielding ink according to any one of claims 1 to 4, a metal mask is used and the thickness of the metal mask is set to 120 to 1.
A printing method characterized by having a thickness of 50 μm. 7. The printing method according to claim 5, wherein a squeegee having a low hardness of 50 to 70 durometer is used when performing the printing.