JPH0564317B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to radiation protective clothing materials and radiation protective clothing using the same. [Prior Art] Conventionally, materials for clothing for radiation protection include sheets filled with lead wool for high-dose conditions, and lead-based powdered rubber, plastic, etc. for low-dose conditions. [Problems to be Solved by the Invention] However, when lead fibers are repeatedly bent, breakage occurs in the lead fibers, resulting in extremely uneven shielding. Furthermore, rubber and plastic materials filled with lead-based powder need to be very thick in order to obtain a shielding effect, resulting in a problem of extremely poor flexibility. [Means for Solving the Problems] The present invention uses polyolefin with a purity of 99.8% by weight.
The present invention relates to a radiation protection clothing material made of a sheet of pure lead foil 1 reinforced on at least one side, and to protective clothing made by sewing or stitching the same. [Function and Examples] As the pure lead foil material used in the present invention, JIS
Of the class 5 lead metals specified in H2105 (1955), the purity is 99.8% by weight or more, especially the purity of 99.9% by weight or more. The thickness of the reinforced pure lead foil is 20 to 500μm,
Preferably 30 to 200 μm, particularly preferably 50 to 200 μm
It is 150 μm. A sheet thinner than 20 μm is not only difficult to manufacture, but also requires a thick reinforcing layer in order to obtain the desired mechanical strength, resulting in an undesirably bulky sheet. If it is thicker than 500 μm, the flexibility is poor, and even if a reinforcing layer is provided, the effect of the present invention cannot be obtained. The reinforcing layer that reinforces the pure lead foil not only improves the mechanical strength of the pure lead foil and increases its durability, but also serves to prevent corrosion of lead. In the present invention, polyolefin is used as a material for the reinforcing layer. The reinforcing layer may be multilayered with two or more layers using two or more types of materials. The thickness of the reinforcing layer varies depending on the physical properties of the polyolefin used, the thickness of the pure lead foil, and the application, but usually the thickness on one side is 10 to 300 μm, preferably 20 to 200 μm.
m, particularly preferably 20 to 100 μm. 10μm
Those thinner than 300 μm generally have weak mechanical strength and are difficult to apply, and those thicker than 300 μm are undesirable because they are bulky. The tensile strength of the reinforcing layer itself is, for example, 0.3 Kg/mm ² or more, preferably 0.5
Kg/ ^mm2 or more, especially 0.8Kg/ ^mm2 or more. Such polyolefins are preferably polymers with good film-forming properties, such as polyolefins that do not contain halogen and have a small amount of tertiary carbon, such as polyethylene, ethylene-ethyl acrylate copolymers, ethylene-propylene copolymers,
Examples include ethylene-vinyl acetate copolymer and ethylene-butene-1 copolymer. Among them, polyethylene has a high effect of shielding neutrons, and is therefore particularly preferred when used for shielding radiation in which neutrons are present. Formation of the reinforcing layer can be performed by various methods. For example, the polyolefin film or sheet may be pasted or glued,
Polyolefin in the form of a solution or emulsion may be applied, or polyolefin heated and melted may be coated. A method may be employed in which the polyolefin precursor is applied by a method such as coating and then cured. The adhesive strength between the pure lead foil and the reinforcing layer does not need to be very strong, for example, it is sufficient if the peel strength is 0.3 kg/inch (ASTM D 1876) or more. Next, embodiments of the clothing material of the present invention will be described based on the drawings, but the present invention is not limited to such embodiments. 1 to 3 are schematic cross-sectional views of embodiments of pure lead sheets used in the present invention, respectively. In Figure 1, 1 is a pure lead foil, with adhesive layers 2 on both sides.
A reinforcing layer 3 is attached via the . In the embodiment shown in FIG. 2, a reinforcing layer 3 is provided on a pure lead foil 1 by direct coating, lamination, or hot pressing. The embodiment shown in FIG. 3 is a pure lead foil 1 provided with a reinforcing layer 3 consisting of two layers 4 and 5. The embodiment shown in FIG. Since the material for radiation protection clothing of the present invention can be made in a large area and can also be sewn, radiation protection clothing can be produced by cutting and sewing the material of the present invention. The manufactured protective clothing inherits the excellent mechanical strength, corrosion resistance, flexibility, and bending resistance of clothing materials, so it does not interfere with the actions of workers. The clothing material of the present invention may also be cut to appropriate dimensions and sewn into clothing made of radiation-resistant material. When sewing or stitching into clothing, it is preferable to use pure lead sheets in a layered manner. Next, the clothing material of the present invention will be explained based on Examples, but the present invention is not limited to these Examples. In addition, the bending resistance, flexibility, and tearing length measured in Examples were measured in the following manner. Bending resistance test Using an insulating paper folding resistance tester (based on JIS P 8115), the following procedure was performed. Width 15mm, length 200
The upper end of the pure lead sheet in the longitudinal direction was fixed and hung, and the lower part was tightened from both sides with a weight having a curved surface with a radius of curvature of 6 mm (tension: 100 g). Next, the weight was moved at a reversal speed of 60 times/minute (tension: 600 g) so that the pure lead sheet was bent using the part of the weight that was in contact with the curved surface as a reference point, and the pure lead sheet was repeatedly bent until cracks appeared. The number of times was measured. Flexibility: After stacking the required number of pure lead sheets (width 200 mm, length 500 mm) so that the thickness converted to lead is 2 mm, the sheets are sealed in a bag slightly larger than the pure lead sheets. This was wound around a mandrel with a diameter of 20 mm, and the ease of winding was determined. The evaluation was rated as ○ if it was easy to wrap, and × if it was difficult to wrap. Tearing length was carried out in accordance with JIS P 8113. Examples 1 to 4 A polyethylene film or a polypropylene film having a thickness shown in Table 1 is superimposed on one or both sides of a pure lead foil having a thickness shown in Table 1 with a hot melt adhesive film having a thickness of about 20 μm interposed therebetween. A pure lead sheet was then produced by hot pressing.
When using polyethylene film, Admer VE300 is used as a hot melt adhesive film.
(manufactured by Mitsui Petrochemical Industries, Ltd.) at 180℃ for 10
When using a polypropylene film, use Admer QE305 (trade name, manufactured by Mitsui Petrochemical Industries, Ltd.) as a hot-melt adhesive film, and press at a pressure of 10 kg/cm ² at 200°C ^. Press molded. The bending resistance, flexibility, and breaking length of each pure lead sheet obtained were measured in the same manner as in Example 1. The results are shown in Table 1. Example 5 A hot-melt adhesive film with a thickness of about 70 μm was laminated as a reinforcing layer on one side of a lead foil having the thickness shown in Table 1, and then hot-pressed to produce a pure lead sheet. In addition, as a hot-melt adhesive film, Surlyn 1652, a modified low-density polyethylene film, is used.
(manufactured by Mitsui Polychemical Co., Ltd.) at 180℃ for 10
Press molding was performed at a pressure of Kg/cm ² . The bending resistance, flexibility, and breaking length of each pure lead sheet obtained were measured in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 A comparative lead sheet was prepared in the same manner as in Example 2, except that a lead foil with a thickness of 100 μm and a purity of 95% by weight was used as the lead foil, and a polyethylene film with a thickness of 50 μm was laminated on both sides as a reinforcing material. Created. Example 1 shows the bending resistance and flexibility of this sheet.
It was measured in the same way. The results are shown in Table 1.

[Table] [Effects of the Invention] The radiation protection clothing material of the present invention is a pure lead sheet in which a thin pure lead foil is used, and one or both sides of which are reinforced with a reinforcing layer made of radiation-resistant polyolefin. Because of this structure, each pure lead sheet itself has excellent resistance to repeated bending fatigue, mechanical strength, corrosion resistance, and flexibility.
Therefore, protective clothing made from these sheets alone or by stacking them also inherits the excellent mechanical strength, corrosion resistance, flexibility, and bending resistance of pure lead sheets, so they are easy to handle, In particular, it has excellent durability against recycling during folding and stretching, has excellent corrosion resistance, and is easy to move and wear.

[Brief explanation of the drawing]

1 to 3 are schematic cross-sectional views of pure lead sheets used in the radiation protection clothing material of the present invention. Main symbols in the drawing: 1...Pure lead foil, 3...Reinforcement layer.

Claims (1)

[Claims] 1. A radiation protection clothing material comprising a sheet of pure lead foil with a purity of 99.8% by weight or more reinforced with polyolefin on at least one side. 2. The material according to claim 1, wherein the pure lead has a purity of 99.9% by weight or more. 3. Radiation protection clothing made of polyolefin, sewn or sewn into a sheet of pure lead foil with a purity of 99.8% by weight or more, reinforced on at least one side. 4. The protective clothing according to claim 3, wherein the pure lead has a purity of 99.9% by weight or more.