JPH0333215A - Polyester fiber and cloth - Google Patents

Abstract

PURPOSE:To provide the subject fiber containing more than specific amount of fine particle of gadolinium oxide and having neutron-shielding performance. CONSTITUTION:The objective fiber is preferably a polyethylene terephthalate fiber containing >=10wt.% of fine particles of gadolinium oxide having an average particle diameter of <=2.0mum (preferably 10mmu to 1mum). In the case of using the fiber in the form of woven fabric, knit fabric or nonwoven fabric, it is preferably mixed with <=30wt.% of a reinforcing fiber having a strength higher than that of the present polyester fiber by >=20%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a polyester fiber having neutron beam shielding ability and a fabric made of the fiber.

[Prior art and its problems]

Science has progressed from the use of neutron beams as nuclear weapons to peaceful use as fusion energy, and reports have recently appeared that nuclear fusion is possible at room temperature. There is a strong need for fibers and fabrics that have a shielding ability of

In contrast, fabrics made of polyethylene fibers containing boron carbide (84C) at a high concentration are commercially available and have an effective shielding effect against relatively low-speed neutron beams. This takes advantage of the deceleration of neutrons due to elastic scattering of hydrogen, which is abundantly contained in polyethylene, and the large absorption cross section of boron (B).

However, since the above-mentioned fiber uses polyethylene as a fiber material, it has to sacrifice consumption performance such as heat resistance, and B4C has extremely high hardness so that it can be used as an abrasive.

It was difficult to make fine particles by pulverization, and it was also difficult to break up the secondary agglomerates.

[Object of the present invention]

The present invention improves the above-mentioned drawbacks and improves the level of neutron shielding fIA fiber and its AI! The aim is to obtain a fabric made of fibers.

[Configuration of the present invention]

The present invention is coupled with the following configuration.

[1) Average particle size2. Polyester fiber containing gadolinium oxide fine particles of υμ or less on a 10-weight plate (2)
The polyester resin that forms polyester fibers is
(8) The polyester fiber according to claim (1), wherein 80 mole % of the constituent units are ethylene terephthalate residues. (4) A fabric having a neutron shielding ability containing at least 30 φ of fibers having a strength 20 or more higher than the strength of the aX mechanical fiber is mixed with the polyester fibers according to claims (1) and (2). A fabric having neutron shielding ability formed by ``A fabric having neutron shielding ability'' The details of the above configuration will be described below.

Neutron shielding uses inelastic scattering by heavy nuclides such as iron and lead, elastic scattering by light nuclides such as hydrogen, and absorption by nuclides with large absorption cross sections such as boron and lithium. The substance with the largest absorption cross section is gadolinium, especially gadolinium dioxide (GdzOs).
is preferable as a stable compound.

The present invention includes gadolinium oxide fine particles having an average particle size of 2.
Below μ, especially good! A value of 1 μ or less is used.

If the average particle size exceeds 2μ, process defects such as stretching and breakage are likely to occur during the fiberization process.

Further, it is preferable to remove coarse particles having a particle size exceeding 5 μm by a method such as 1-class classification or PA. Also, the casing is also ultra-fine 1
For example, if a material of 10 mμ or less is used.

Secondary agglomerated metal tends to form, which may lead to unfavorable results.

The amount of gadolinium oxide used in the present invention is preferably 10 or more. Even if the amount is less than this, it is possible to shield by increasing the amount of fiber used for shielding. It becomes too late in the evening when the amount is so large that it is no longer practical.

In the present invention, polyester is preferably used as the 61 resin forming the fiber. This is form stability.

This is because it is a desirable material for fabrics (for clothing) in terms of water resistance and other consumption performance.

This polyester includes dicarboxylic acids such as aromatic dicarboxylic acids such as terephthalic acid, isophthalic eR, and naphthalene dicarboxylic acid, and aliphatic dicarboxylic acids such as sepacic acid, azelaic acid, and adipic acid.

Diols include ethylene glycol, butylene glycol, propylene glycol, cyclohexanediol,
Examples include those synthesized from hexanediol and the like. Among these, those containing aromatic dicarboxylic acids as a main component are preferably used.

Among the polyesters of C), polyethylene tele-7-merate type is particularly preferable, and among these polyesters, the structural unit of which is 8
Particularly preferred are polyesters in which at least a molar number of υ residues are ethylene terephthalate residues.

Naturally, formulations that are modified with sulfoisophthalic acid #1, isophthalic acid, naphthalene dicarboxylic acid, etc., or derivatives thereof, and in which additional components such as polyalkylene glycol are added are acceptable.

Furthermore, the gadolinium oxide-containing polyester fiber used in the present invention does not necessarily need to be made into fibers alone, and may be spun, for example, as a core-sheath composite or as a cover yarn. Furthermore, it can be used as a polyester film, and depending on the type of polyester, it can be used as an adhesive to provide neutron shielding, or as a coating material or molding material (engineering plastic).

It can be used for neutron beam shielding.

In the present invention, the addition of gadolinium oxide to the polyester can be selected arbitrarily during the steps from the synthesis of m-lipid to the spinning box, but due to the characteristics of gadolinium oxide, when a dicarboxylic acid such as terephthalic acid is used as a starting material for synthesis, It is preferable to do this after the esterification reaction with the diol is completed. This is because gadolinium oxide reacts with acid. When using esterified products such as 0- or dimethyl terephthalic acid and diols such as ethylene glycol as raw materials, the diol is mixed with pulverization using a vibrating mill, planetary mill, etc. It is preferable to disperse the particles to a high degree using a device having a crushing ability, and filter the particles using a stainless steel fine wire nonwoven fabric filter or the like to remove coarse particles before use. The degree of polymerization of the polyester resin may be within a range that allows it to be made into fibers, but at least the degree of polymerization of phenol/tetrachloroethane = 1/1 (lt ratio) at 30.0°C in a solvent after correcting the amount of added particles is sufficient. A material with an intrinsic viscosity of 0.4 or more should be used.

When the fibers having neutron beam shielding properties according to the present invention are used as fabrics such as woven fabrics, knitted fabrics, and non-woven fabrics, the fibers can
It should be made up of more than enough weight. this is,
This is because neutron beams pass through portions made of fibers that do not have neutron beam shielding ability, creating gaps in the R shielding ability. In this sense, sufficient consideration should be given to the texture, date, etc. so that the fibers according to the present invention cover the entire fabric without any gaps.

Furthermore, since the fIR fiber of the present invention contains gadolinium oxide fine particles of more than 10% by weight, it inevitably becomes weak in strength. Therefore, in order to reinforce this, it is preferable to use fibers that are at least 20% stronger in strength than the above fibers as a reinforcing material. The mixing amount is 30]it% in order to prevent neutrons from passing through as described above.
It is necessary to use the following mixing amount. Although the mixing method is arbitrary, it is preferable to mix the single fibers together as much as possible in order to prevent neutrons from passing through. As the reinforcing agent, it is preferable to use one with higher strength.1 For example, aramid powder1
Preferred examples include Kevlar (trade name, manufactured by Du Pont, etc.) and polyarylate fiber (Pectran, trade name, manufactured by Kuraray, etc.).

This will be explained below using examples.

(Example-1, Comparative Example-1) Gadolinium oxide with an average particle size of 1.0μ and a maximum particle size of 2μ was crushed in ethylene glycol using a vibration mill, and concentrated to 1.
A 20% by weight dispersion was prepared. When this was filtered through a stainless steel fine wire nonwoven fabric filter (porosity 10μ), no front crosspiece was observed.

Using this dispersion, dimethyl terephthalic acid, and ethylene glycol, the amount of gadolinium oxide added to the finished polymer was adjusted to 30% by weight and more than 8% by weight, and 500 ppm of zinc acetate was added as a transesterification catalyst. Using tri-n-butyl phosphate as an active catalyst and 400 m of antimony oxide (SbzO3) as a polymerization catalyst, polymerization was carried out in a conventional manner, strands were cut, and polyethylene terephthalate containing 30% by weight of gadolinium oxide and 8% by weight was added. Obtained. The corrected intrinsic viscosity of each (excluding those outside the particles) was tl 60 /and 0.653. These will be referred to as polymers A and B.

These two polymers were spun and stretched using a method of 1507
A drawn yarn of Neil-32 filament was obtained. Let these be fibers A and B, respectively.

[1A(7) Remaining ID 2.9 y /a -25%,
The strength and elongation of fR fiber B was 4.3 f/d -31.

For fibers A and B, high-density fabrics (fabric weight 400 f/rr?) of the same standard were created, and neutrons (wavelength 2.4
When we measured the shielding ability of 4 people), the fabric made of fiber A had a shielding rate of about 80%, but f#! The fabric made of Fiber B had a shielding rate of about 20%. The former will be referred to as Example-1, and the latter will be referred to as Comparative Example-1.

(Example-2) A 25-denier-6 filament (strength: 21r, /cl) of Pectran (trade name: Bolyarylate fiber, manufactured by Kuraray) was mixed with the fR fiber A of Example-1, and the residual degree was measured. However, it showed a strength of 4.5 r/d.

A woven fabric of the same specifications as Example 1 was prepared using this mixed fiber yarn, and the neutron shielding rate was measured, and it was found to be approximately 7°.

Claims (1)

[Scope of Claims] (1) A polyester fiber having neutron shielding ability that contains 10% by weight or more of gadolinium oxide fine particles with an average particle size of 2.0μ or less. (2) A polyester resin forming the polyester fiber is a constituent unit of the polyester fiber. (8) The polyester fiber according to claim (1), in which 80 mole % of the residues are ethylene terephthalate residues. Fabric having neutron shielding ability (4) The polyester fibers according to claims (1) and (2) are mixed with 30% by weight or less of fibers having a strength of 20% or more higher than the strength of the fibers. Fabric with neutron shielding ability