JPS6036497B2 - Method for producing lead or lead alloy fiber sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing lead or lead alloy fiber sheets,
More specifically, lead or lead alloy fibers are assembled into a sheet, and the assembly is glued together using an organic adhesive.The assembly is then vacuum packed in a plastic bag, and is tightly adhered to achieve a certain level of strength, flexibility, radiation shielding properties, etc. The present invention relates to a method of manufacturing a sheet having

Conventionally, lead or lead alloy fiber sheets have been produced by covering an aggregate of lead or lead alloy fibers in a sheet shape (hereinafter simply referred to as an aggregate) with cloth and then quilting it;
The methods used include placing the aggregate between plastic films and fusing the plastic, and mixing lead powder or lead oxide powder into plastic and forming it into a sheet.

However, in the quilting method, the perforations of the quilting were opened or cut during use, and a predetermined weight per unit area within the assembly could not be maintained. Also, in severe cases, there was a drawback that cracks appeared in the aggregate. In the method of sandwiching the aggregate between plastic films, the thickness of the aggregate is limited because the plastics are fused together rather than the plastic and the aggregate. In addition, in the method of mixing powdered lead or lead oxide into plastics, etc., if the weight of the metal exceeds 50%, the distribution of the metal may become uneven.
It had the disadvantage of losing flexibility and strength, making it impractical. The present invention provides a method for manufacturing lead or tin alloy fiber sheets that eliminates the above-mentioned drawbacks, and is characterized by bonding aggregates with an organic adhesive, The aggregate adhered with a type of adhesive is vacuum-packed in a plastic bag made of a laminate film in which the inner layer has a lower melting point than the outer layer, and then heat treated to fuse the inner layer of the laminate film to the aggregate. It's about doing.

The lead or lead alloy fiber in the present invention is an alloy of lead, lead-antimony, lead-tin, lead-calcium, etc.
In particular, when used for radiation shielding, alloys that do not exhibit characteristic x-rays are manufactured by extrusion, cutting thin plates, melt spinning, etc.

The lead or lead alloy fiber thus formed preferably has a diameter of 0.3 ribs or less in order to maintain good flexibility when made into a sheet, and the lower limit is 0.03 ribs for economic reasons. The skin length and length are preferably 10 cm or more (the longer the better). The aggregate is formed by forming the above-mentioned lead or lead alloy fibers into a mat, nonwoven fabric, woven fabric, etc., or by stacking these. Next, this aggregate is adhered using an organic adhesive. This adhesive has a viscosity and surface tension that allows it to penetrate into the inside of the aggregate by capillary action, and the adhesive itself is flexible, such as raw rubber, chloroprene, nitrile, acrylic, etc.
Silicone rubber-based materials are preferred. Bonding methods using these adhesives include pouring adhesive adjusted to an appropriate viscosity onto the aggregate and letting it soak in using a spatula, brush, etc.
A method of reducing pressure on one side (lower side) and letting the adhesive seep in.
A method in which the adhesive is soaked while passing the aggregate between two rolls, a method in which the aggregate is immersed in an adhesive adjusted to an appropriate viscosity (this may be done under reduced pressure), or a method in which it is sprayed. methods etc. may be adopted. The amount of adhesive used for bonding is preferably such that the weight ratio of the aggregate after bonding is 80% or more, and specifically, it is 0.02 to 0.02%, depending on the density of the aggregate. Approximately 2 evenings/day.
It goes without saying that the density of the aggregate should be selected appropriately depending on the application; for example, if the aggregate fibers are laminated in layers equivalent to the thickness of one lead plate, the aggregate will have a thickness of approximately 4 sides and a weight of approximately 1.5 mm. It will be 13 ta'. In addition, aggregates formed from fibers produced by the fused paper yarn method can be bonded with an adhesive while the fiber surface remains clean, resulting in improved adhesive strength and higher performance than when using fibers produced by other methods. is also preferable.

Since the adhesive has been adjusted to have an appropriate viscosity, it partially soaks into the aggregate through capillary action and is evenly distributed inside the aggregate.

Therefore, the aggregate can also be made uniform. When bonding with such an adhesive, the infiltration along the fibers of the aggregate does not completely fill the inside of the aggregate, so the aggregate bonded with an adhesive has appropriate air permeability. Moreover, such an aggregate has not only air permeability but also flexibility and appropriate strength. The present invention is to vacuum-pack the aggregate adhered with the organic adhesion agent obtained as described above in a plastic film bag to obtain a lead or lead alloy fiber sheet with the plastic film bag tightly attached.

Plastic films are laminated films when the inner layer has a lower melting point than the outer layer, specifically polyethylene/
Laminated films of nylon, polypropylene, polyethylene/tetron, etc. are preferred. The aggregate adhered with an organic adhesive is placed in such a plastic film bag and vacuum packed. As a result, the adhesive-bonded assembly is evenly encapsulated in the plastic film bag by a uniform pressing force. This is then heat treated to bring the aggregate and plastic film into close contact. Due to this heat treatment, since the plastic film is used as a laminate of films with different melting points, by vacuum packing with the lower melting point side as the inner layer, the inner layer film softens first and comes into close contact with the aggregate. In the method of the present invention, the aggregate adhered with an adhesive is placed in a plastic film bag and vacuum packed, and then heat-treated so that the aggregate and the plastic film are uniformly adhered to each other. It is possible to easily produce long sheets without the need for special equipment, and it is also possible to bond materials that do not have adhesive strength at room temperature. As described above, according to the present invention, since the aggregate of lead or gold-platinum alloy fibers is bonded with an organic adhesive, it has excellent breathability, flexibility, and strength, and has a low metal content by weight. An extremely high-strength sheet is obtained, and this is further vacuum-sealed in a plastic film and heat treated to firmly adhere the plastic film, resulting in a lead or lead alloy fiber sheet with extremely excellent flexibility, strength, and waterproofness. Since it can be washed with water, a sheet that can be used as a radiation shielding material, a heat insulating material, etc. can be obtained.

Examples are shown below.

Comparative Example Almost continuous lead fibers with a diameter of 120 microns were made into iron threads using the fused bush thread method, and these were directly stacked on a belt conveyor to have a width of 20 cm, a length of 100 cm, a thickness of 4 sides, and a weight of 2. 3
A net-like lead fiber aggregate weighing 1 kg (1 rib equivalent to a lead plate thickness) was obtained.

Transfer this aggregate onto a polyethylene plate and add a certain amount of raw rubber adhesive adjusted to an appropriate viscosity (50 pieces of raw rubber).
was poured onto the aggregate, and a spatula-shaped object was used to soak it evenly into the aggregate, bonding the fibers of the aggregate together, and then drying.
When the surface was no longer sticky, the assembly was turned over, and in the same manner, a certain amount of raw rubber adhesive was soaked in and adhered, followed by drying. As a result, a sheet with a high weight ratio of 1.18 mm/cm and a metal component weight of 1.13 mm/cm, and thus a metal content of 95.76% was obtained.
This sheet was breathable and had satisfactory strength and flexibility as shown below. Bending test (1
80o) 100-150 times tensile strength (1
(per width) Maximum load: 1.1k9 A lead fiber aggregate was formed in the same manner as in the example, and adhesive made by dissolving raw rubber in an organic solvent was applied to this for 0.05 minutes/day to bind the fibers of the aggregate together. Glued.

After leaving this for one day, polyethylene 80μ/
Put it in a nylon 20mm laminated film tube,
It was vacuum sealed to about 0-1 to 10-3 Hg using a vacuum pump. Thereafter, heat treatment was performed at 12,000 for 1 minute.
The lead fiber sheet thus obtained maintained a uniform adhesion state and was excellent in feel and handling. It also has excellent strength, and its flexibility is 1800 times higher than that of conventional products, which are made by sewing and joining plastic films to aggregates.
The results of the bending test showed that cracks occurred after about 50 turns, and while in the comparative example cracks occurred after 100 to 150 turns, 2
It could withstand being bent over 00 times. Note that even when the aggregate was bonded with an adhesive, dried, and immediately subjected to vacuum sealing and heat treatment, there was no change in the performance of the resulting sheet.

Claims (1)

[Claims] 1 A laminate film in which lead or lead alloy fibers are assembled into a sheet shape and the fibers are adhered to this using an organic adhesive, with the inner layer having a lower melting point than the outer layer. A method for producing a lead or lead alloy fiber sheet, which is vacuum-packed in a plastic bag and then heat-treated to fuse the inner layer of the laminate film to the aggregate.