JP2899997B2 - X-ray shielding plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray shielding plate comprising a transparent vinyl chloride resin plate containing a large amount of a tin stabilizer.

[0002]

2. Description of the Related Art Heretofore, a glass X-ray shielding plate containing a lead component has been used for applications such as viewing windows and partitions of an X-ray room. However, such an X-ray shielding plate is heavy in weight and easily broken, which makes transport and handling inconvenient.

[0003] Under such circumstances, a transparent acrylic resin X-ray shield plate containing a large amount of lead has recently been frequently used.

[0004]

However, acrylic resin X-ray shielding plates have the advantage of being lighter and less susceptible to cracking than those made of glass, but have the problem of inferior chemical resistance and high cost. There was a problem.

In order to solve this problem, the present inventors have conceived of using an inexpensive vinyl chloride resin having excellent chemical resistance in place of the acrylic resin. , It is difficult to obtain an X-ray shielding plate having a practically satisfactory transparency because of a significant decrease in light transmittance when an effective amount of lead is contained for the X-ray shielding. did.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a relatively inexpensive vinyl chloride resin having a good X-ray shielding effect and having a practically satisfactory transparency. An object of the present invention is to provide an X-ray shielding plate.

[0007]

In order to achieve the above object, an X-ray shielding plate according to the first invention comprises a transparent vinyl chloride resin plate containing a tin stabilizer, and the tin content of the resin plate is reduced. It is characterized by being at least 1% by weight. Then, the X-ray shielding plate according to the second invention is formed by laminating and integrating a transparent vinyl chloride resin plate containing a maleate tin stabilizer on at least one side of a transparent vinyl chloride resin plate containing a mercapto tin stabilizer. The laminated plate is characterized in that the total tin content of the laminated plate is 1% by weight or more.

[0008]

The tin stabilizer is a known stabilizer (a stabilizer against heat) conventionally added to a vinyl chloride resin, and the amount of the tin stabilizer is usually as small as 0.5% by weight or less in terms of tin content. is there. However, when the added amount of the tin stabilizer is increased, tin in the tin stabilizer is a metal that absorbs X-rays, so that the X-ray shielding effect becomes gradually stronger, for example, the tin content becomes 1% by weight. An 8 mm thick vinyl chloride resin plate having a high content of a tin stabilizer added thereto exhibits an X-ray shielding effect of about 0.06 mmPb equivalent, and the higher the tin content, the greater the X-ray shielding effect. Therefore, when the tin content is 1% by weight or more as in the X-ray shielding plates of the first and second inventions, a satisfactory X-ray shielding effect of a plate thickness of 8 mm and a Pb equivalent of about 0.06 mm or more is exhibited. Is done.

By the way, typical tin stabilizers include a mercapto tin stabilizer and a maleate tin stabilizer.
They differ in their nature. As the amount of the added mercapto tin stabilizer increases, the total light transmittance of the vinyl chloride resin plate improves. When the tin content in the vinyl chloride resin plate is about 6.5 to 7% by weight, the total amount of the tin stabilizer is 6.5 to 7% by weight. Light transmittance is the highest,
As the addition amount is further increased, the total light transmittance gradually decreases. On the other hand, in the case of the maleate tin stabilizer, the total light transmittance is highest when the tin content in the vinyl chloride resin plate is approximately 1.5 to 2% by weight, and when the added amount is further increased, the total light transmittance is increased. The rate drops. Therefore, in the case of a single plate of a vinyl chloride resin like the X-ray shielding plate according to the first invention,
Depending on the tin content, use different types of tin stabilizers, for example,
When the tin content is about 1 to 3.5% by weight, a maleate tin stabilizer may be used, and when the tin content is further increased, a mercapto tin stabilizer may be used. If the agents are properly used, an X-ray shielding plate having practically sufficient transparency can be obtained even if the tin content is high.

As described above, an X-ray shielding plate having good transparency can be obtained even if a large amount of a mercapto tin stabilizer is added, but if the addition amount is too large, plasticity increases and rigidity decreases. Therefore, X with a high tin content and practical strength
If it is desired to obtain a wire shielding plate, as in the second invention, a vinyl chloride resin plate containing a maleate tin stabilizer is laminated and integrated on at least one surface of a vinyl chloride resin plate containing a mercapto tin stabilizer. It is sufficient to greatly increase the amount of the mercapto tin stabilizer, and in this case, even if the rigidity of the vinyl chloride resin plate containing a large amount of the mercapto tin stabilizer decreases, a small amount of the maleate tin stabilizer may be used. Since it is reinforced by a hard vinyl chloride resin plate, an X-ray shielding plate having sufficient practical strength as a whole can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the X-ray shielding plate according to the first invention. The X-ray shielding plate is a transparent protective film on both sides of a transparent vinyl chloride resin plate 1 containing a tin stabilizer. 2, 2 are provided.

The vinyl chloride resin plate 1 has a tin content of 1
The tin stabilizer is added so as to be at least% by weight, and an appropriate amount of an ultraviolet absorber, a lubricant, a modifier, a pigment, etc. is added as needed.

As the tin stabilizer, laurate-based, maleate-based and meccapto-based stabilizers are used. A typical laurate tin stabilizer is dibutyltin dilaurate (tin content 18.8%). As the maleate tin stabilizer, dibutyltin maleate, bis (di-n
-Butyltin monoalkylate) maleate, dibutyltin alkyl maleate, bis (di-n-butyltin alkyl maleate) maleate, dibutyltin laurate maleate and the like. The mercapto tin stabilizer is Sn-
Has S bond, sulfide, mercaptide, mercapto acid ester, mercapto alcohol organic acid salt,
There are S, O-mercaptocarboxylate, mercaptocarboxylate / maleate and the like, and a typical one is bis (isooctyl or 2-ethylhexyl or 2-ethylhexylthioglycolate). Among these tin stabilizers, mercapto-based and maleate-based tin stabilizers having excellent transparency and thermal stability are preferably used. Laurate tin stabilizers are initially colored and have slightly poor transparency.

When the vinyl chloride resin plate 1 is a plate having a thickness of about 8 mm containing a maleate tin stabilizer, as shown in the graph of FIG. 3, the total amount of the resin plate increases as the amount of tin stabilizer added increases. The light transmittance sharply increases, and when the tin content in the resin plate becomes about 1.5 to 2% by weight, the total light transmittance becomes the highest at about 72%. Light transmittance decreases.

On the other hand, when the vinyl chloride resin plate 1 is a plate having a thickness of about 8 mm containing a mercapto tin stabilizer,
As shown in the graph, the tin content in the resin plate was about 6.5.
When it is 最高 7% by weight, the total light transmittance is as high as about 84%, which is higher than the maximum value of the resin plate containing the maleate tin stabilizer. Then, even if the addition amount is further increased, the total light transmittance does not decrease rapidly, but gradually decreases to maintain good transparency.

Therefore, in order to obtain practically sufficient transparency, the type of the tin stabilizer is properly used according to the tin content of the vinyl chloride resin plate 1, and the tin content of the resin plate 1 is set to 1 to 3. When it is set to about 5% by weight, it is important to add a maleate tin stabilizer, and when setting the tin content even higher, it is important to add a high amount of a mercapto tin stabilizer.

As described above, the total light transmittance of the vinyl chloride resin plate 1 differs depending on the type of tin stabilizer, but the X-ray shielding effect can be understood from the graph of FIG. The X-ray shielding effect is proportional to the tin content of the resin plate 1 and the higher the tin content, the better the X-ray shielding effect. If the tin content is the same, the X-ray shielding effect is improved as the thickness of the vinyl chloride resin plate 1 increases. However, when the polyvinyl chloride resin plate 1 becomes thicker, the total light transmittance decreases.

The tin content of the vinyl chloride resin plate 1 is 1% by weight.
When the tin containing X-rays is contained in a large amount, the thickness of the vinyl chloride resin plate 1 becomes 8
mm, about 0.06 m as can be seen from the graph of FIG.
An X-ray shielding effect of mPb equivalent or more is obtained, and the total light transmittance is as good as about 70%. Therefore, the required quality as an X-ray shielding plate used for a viewing window of an X-ray room or the like can be satisfied. In particular, when a mercapto-based tin stabilizer is added in a high amount so that the tin content becomes about 6.5% or more, the total light transmittance becomes 80% or more and the X-ray shielding effect becomes 0.1 mmPb equivalent or more. Quality can be fully satisfied. On the other hand, when the tin content is lower than 1% by weight, for example, 0.5% by weight, the thickness of the vinyl chloride resin plate 1 is 8 mm.
However, in order to reduce the total light transmittance and obtain the same X-ray shielding effect as above, the thickness of the vinyl chloride resin plate 1 must be 2
Since the thickness needs to be doubled, the total light transmittance further decreases as much as the thickness increases. Therefore, in this case, it is difficult to satisfy the required quality. As described above, in order for the vinyl chloride resin plate 1 to have practically satisfactory transparency and an X-ray shielding effect, the tin content needs to be 1% by weight or more. In particular, when a maleate tin stabilizer is used as the tin stabilizer, the total light transmittance can be increased to 50% or more in terms of 8 mm by setting the tin content to 1.0 to 3.0% by weight. preferable. If the content is 3.0% by weight or more, kneading becomes difficult and molding becomes impossible in practice, so the above range is preferable. When a mercapto tin stabilizer is used, the tin content may be set to 3.0% by weight or more.

The graph of FIG. 3 shows the total light transmittance (%) measured for the test pieces a to k having the compositions shown in Table 1 below and the X-ray shielding effect (when the thickness of the test piece is converted to 8 mm). (Equivalent to mmPb).

[0021]

[Table 1]

The protective film 2 covering the vinyl chloride resin plate 1 is not essential, but if such a protective film 2 is provided,
Even if the vinyl chloride resin plate 1 is a plate whose rigidity is lowered by adding a mercapto tin stabilizer at a high level, the surface is protected and the scratch is hardly damaged, and if the protective film 2 having excellent weather resistance is used, the chloride is reduced. There is an advantage that deterioration of the vinyl resin plate 1 is suppressed. As the protective film 2, various transparent synthetic resin films are used. In particular, an acrylic resin film excellent in transparency, weather resistance, and adhesion to a vinyl chloride resin plate, or a weather resistance by adding a high ultraviolet absorber. A vinyl chloride sheet having improved properties, a vinyl chloride resin sheet having a tin content of 0.5% by weight or less, and the like are preferably used.

Next, an embodiment of the X-ray shielding plate according to the second invention will be described with reference to FIG.

This X-ray shielding plate comprises a transparent vinyl chloride resin plate 1A containing a maleate tin stabilizer and a transparent vinyl chloride resin plate 1 containing a maleate tin stabilizer on both sides of a transparent vinyl chloride resin plate 1A containing a large amount of a mercapto tin stabilizer.
B and 1B are laminated and integrated, and the amount of a mercapto tin stabilizer and the amount of a maleate tin stabilizer are added so that the tin content of the entire laminate is 1% by weight or more. And the thickness ratio of the vinyl chloride resin plates 1A and 1B. However, even in this case, it is desirable to adjust the addition amount of the mercapto tin stabilizer and the maleate tin stabilizer so that the total light transmittance of the vinyl chloride resin plates 1A and 1B is at or near the maximum.

As described above, the vinyl chloride resin plate 1A containing the mercapto tin stabilizer has good transparency even when the mercapto tin stabilizer is added at a high level, but the plasticity becomes stronger as the amount of addition increases. As a result, the rigidity is lost, the surface hardness is lowered, and the softening temperature is lowered. Further, the vinyl chloride resin plate 1A using the mercapto tin stabilizer has lower weather resistance than the vinyl chloride resin plate 1B using the maleate tin stabilizer.
On the other hand, in the vinyl chloride resin plate 1B containing the maleate tin stabilizer, the addition amount of the maleate tin stabilizer is relatively small so as to obtain a tin content of about 1 to 2% by weight at which good transparency is obtained. Because it is in a small amount, it is much harder than the vinyl chloride resin plate 1A, and has excellent rigidity, surface hardness, and softening temperature.
Moreover, the weather resistance is good. Therefore, when such a hard vinyl chloride resin plate 1B, 1B is laminated and integrated on both surfaces of the vinyl chloride resin plate 1A and reinforced, the mercapto tin stabilizer of the vinyl chloride resin plate 1A is increased in order to enhance the X-ray shielding effect. Even if the addition amount is increased, it is possible to obtain an X-ray shielding plate having sufficient strength for practical use and good transparency.

Table 2 below shows a vinyl chloride resin plate having the composition of d and j in Table 1 and a 6 mm vinyl chloride resin plate 1A using the composition of j in Table 1 on both surfaces. The X-ray shielding effect, total light transmittance, and flexural modulus of each of the vinyl chloride resin laminates obtained by laminating the 1 mm vinyl chloride resin plates 1B, 1B using the compositions are shown.

[0027]

[Table 2]

As can be seen from Table 2, the flexural modulus of the laminate is improved by the vinyl chloride resin plates 1B, 1B.
The line shielding and the transparency are numerical values that have no practical problem.

The vinyl chloride resin plate 1B does not need to be laminated on both sides of the vinyl chloride resin plate 1A as in this embodiment, but may be laminated on at least one surface.

[0030]

As is clear from the above description, the X-ray shielding plate of the first invention has practically satisfactory transparency and X-ray shielding effect, and is made of vinyl chloride resin. It has good chemical properties and can be manufactured at low cost. Also,
In addition to the above, the X-ray shielding plate of the second invention has an effect that practically sufficient strength can be imparted even if the X-ray shielding effect is improved by adding a mercapto tin stabilizer at a high level.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an X-ray shielding plate according to the first invention.

FIG. 2 is a sectional view showing one embodiment of an X-ray shielding plate according to the second invention.

FIG. 3 is a graph showing the relationship between tin content, X-ray shielding effect, and total light transmittance for a vinyl chloride resin plate containing a maleate tin stabilizer and a vinyl chloride resin plate containing a mercapto tin stabilizer. .

[Explanation of symbols]

 1,1A, 1B Vinyl chloride resin plate 2 Protective film

Claims (2)

(57) [Claims] 1. An X-ray shielding plate comprising a transparent vinyl chloride resin plate containing a tin stabilizer, wherein the tin content of the resin plate is 1% by weight or more. 2. A laminated plate in which a transparent vinyl chloride resin plate containing a maleate tin stabilizer is laminated and integrated on at least one surface of a transparent vinyl chloride resin plate containing a mercapto tin stabilizer. An X-ray shielding plate, characterized in that the tin content of the X-ray shield is 1% by weight or more.