JPH03179056A - Radiation-resistant molding material and radiation-screening molding material - Google Patents

Abstract

PURPOSE:To prepare a radiation-resistant molding material excellent in the radiation resistance and useful as a material for nuclear reactors, space and aeronautics use, etc., by compounding a polymer contg. specific repeating units into the material. CONSTITUTION:A polymer contg. repeating units of the formula is compounded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a radiation-resistant molding material and a radiation-shielding molding material, and more specifically, it is suitable for use as, for example, a nuclear reactor material, a breeder reactor material, or an aerospace material. This invention relates to radiation-resistant molding materials and radiation-shielding molding materials that can be used.

[Prior Art and Problems to be Solved by the Invention] With the development of the nuclear power industry, it is expected that more and more equipment will be used in the vicinity of radiation generating locations such as nuclear reactors and breeder reactors.

Therefore, molding materials used in these devices are required to have excellent radiation resistance.

However, conventionally used organic materials are
There are problems in that it has poor radiation resistance, and also deteriorates due to radiation irradiation, resulting in significant loss of the characteristics of the material itself.

In particular, polymeric materials have a problem in that their performance deteriorates due to molecular chain scission and depolymerization.

Under these circumstances, a new polymer material with excellent radiation resistance is desired.

The present invention has been made based on the above-mentioned circumstances.

An object of the present invention is to provide a material with excellent radiation resistance and a material with excellent radiation shielding properties.

[Means for solving the problem] The invention according to claim 1, which is a distant relative of the above object,
A radiation-resistant molding material characterized by containing a polymer having a repeating unit represented by the following formula (1): ().

The invention according to claim 2 is a radiation-shielding molding material containing the polymer according to claim 1 and lead and/or a lead compound.

The invention according to claim 3 is characterized in that the content of the lead and/or lead compound is 5 to 80% by weight.
The radiation-shielding molding material described in .

Radiation-resistant molding material> Monopolymer The radiation-resistant molding material of the present invention is characterized by containing a polymer having a repeating unit represented by general formula (I) as a main component.

The polymer having the repeating unit represented by the general formula (I) in the present invention has a reduced viscosity measured at 30°C in a solution with a concentration of 0.5 g/dl using N-methyl-2-pyrrolidone as a solvent. [ηsp/cl is 0.3 to 2.0d
It is desirable that it be jL/g.

In addition, the said polymer in this invention may have repeating units other than the said repeating unit (1) in the range which does not impede the objective of this invention.

Examples of other repeating units include repeating units having the following structure.

The repeating unit (■) of the above structure can be easily dehydrated by heating and converted into the repeating unit represented by the above formula (I).

The polymer in the present invention can be produced, for example, in a primary manner.

That is, it is obtained by reacting 4.4'-bis(2,3-dicarboxyphenoxy)biphenyldiacid anhydride and benzidine in a neutral polar solvent.

The 4.4°-bis(2,3-dicarboxyphenoxy)biphenyl diacid anhydride can be represented by the following formula.

Benzidine is a compound with the following structure.

Examples of the neutral polar solvent include dimethylformamide, dimethylacedoacide, N-methylpyrrolidone, dimethylsulfoxide, sulfolane, diphenylsulfone, and dimethylimidazolidinone.

These neutral polar solvents may be used alone, or two or more may be used in combination as a mixed solvent, or other inert organic solvents, such as water can be retained outside the reaction system. It may also be used as a mixed solvent with an aromatic hydrocarbon solvent such as benzene, toluene, xylene, etc., which is an azeotropic solvent for removal.

The ratio of 4,4°-bis(2,3-dicarboxyphenoxy)biphenyldiacid anhydride to benzidine is:
substantially equimolar amounts.

The reaction temperature in carrying out the polymerization reaction is usually 0 to 5
The reaction time is usually 5 minutes to 10 hours, preferably 30 minutes to 1 hour.

The reaction product liquid obtained after the polymerization reaction is treated by a normal method.
For example, the polymer having the repeating unit represented by formula (I) can be isolated by precipitating the polymer using a solvent, collecting it, and subjecting it to a purification operation.

In addition, when benzidine and 4,4'-bis(2,3-dicarboxyphenoxy)biphenyldiacid anhydride are reacted, a part of the repeating unit represented by the above formula HI) is contained in the polymer. However, this does not in any way impede the purpose of the present invention.

The polymer thus obtained is itself a material with excellent radiation resistance.

Therefore, this polymer can be molded into various shapes by extrusion molding, injection molding, press molding, cast molding, etc., such as pipe materials such as vibrators, bars, plates, sheets, etc.
Film, wire coating.

It can be used as a radiation-resistant molding material by molding it into coach ink materials, connectors, boxes, tray backings, filter paper, etc.

The polymer may be combined with an inorganic reinforcement, that is, by forming a combination of the polymer and the inorganic reinforcement, or by forming a composite of the polymer and the inorganic reinforcement. This further increases its mechanical strength.

The inorganic reinforcing materials include glass fiber, glass mat, carbon fiber carpet, graphite, carbon black, asbestos, ferrite, zirconia, titania, mica, clay, talc, calcium carbon, magnesium carbonate, dolomite, calcium sulfate, magnesium sulfate, Examples include calcium silicate, montmorillonite, bentonite, silicon carbide, silicon nitride, and boron nitride.

These inorganic reinforcing materials may be used alone or in combination of two or more.

There is no particular restriction on the form of the inorganic reinforcing material,
It may be in any form of granules, plates, or fibers.

However, the preferred inorganic reinforcing material is a fibrous inorganic reinforcing material.

Examples of the fibrous inorganic reinforcing material include glass fiber, carbon am, aromatic polyamide fiber, etc. from the viewpoint of heat resistance, mechanical strength, chemical resistance, and the like.

These contribute to improving heat resistance, mechanical strength, chemical resistance, and the like. These can be used alone or in combination of two or more.

Forms of use of these fibrous inorganic reinforcement materials include chopped strand mats, m-length fiber mats, woven fabrics (filament yarn fabrics, spun fabrics, stretch fabrics, etc.), and knitted fabrics (stockinette, jersey, etc.). One kind or a combination of two or more kinds can be used.

When using a fibrous inorganic reinforcement as the inorganic reinforcement, the fiber diameter of the fibrous inorganic reinforcement is usually 5 to 20 g.
, preferably 7 to 15 g, and its aspect ratio is usually 100 to 3,000, preferably 500 to 2
,000.

In compositions of polymers and inorganic reinforcements or composites of polymers and inorganic reinforcements, the amount of polymer used is usually 2
0 to 85% by weight, preferably 30 to 80% by weight, so the mineral reinforcement is usually 15 to 80% by weight, preferably 20 to 70% by weight.

If the amount of the polymer used is less than 20% by weight or more than 85% by weight, the mechanical strength of the heat-resistant laminate decreases.

The composition of the polymer and the inorganic reinforcing material can be prepared using a mixer or the like, and the composite of the polymer and the inorganic reinforcing material can be produced by one of the following three methods. should be adopted.

(a) A method in which powder or pellets of a polyether copolymer is uniformly dispersed onto a fiber reinforced mat, fabric, etc. and molded under heat and pressure.

(b) A method in which a sheet is manufactured from a pellet of polyether copolymer by extrusion molding, compression molding, etc., and this sheet is laminated on a mat, fabric, etc. of fibrous inorganic reinforcing material, and heated and pressed.

(c) A method that appropriately combines the methods (a) and (b) above.

The composition of the polymer and the inorganic reinforcing material and the composite of the polymer and the inorganic reinforcing material can be used in various molding amounts in the same manner as the above polymer.

<Radiation-shielding molding material> The radiation-shielding molding material according to claim 2 comprises the polymer according to claim 1 (and optionally the polymer and an inorganic reinforcing material).
The polymer according to claim 2, which comprises lead particles and/or a lead compound, is as described above.

The size of the lead particles is not particularly limited and can be appropriately determined depending on the intended use. - By way of example, the particle size of the lead particles used is between 5 and 500 pL, especially between 10 and 100 #Lm.

The lead compound may be an inorganic compound containing lead or an organic compound containing lead, such as lead sulfide, -lead oxide, lead carbonate, lead sulfate, lead hydroxide, lead chloride, and iodide. Lead, lead nitrate, white lead, lead chromate, lead dioxide, calcium positive lead acid, calcium meta lead acid, red lead, lead sesquioxide, lead acetate, lead propionate, and the like.

There are no particular restrictions on the form of these lead compounds;
It may be used in powder form or in lump form.

The lead or lead compound may be used alone or in combination of two or more types, or lead and a lead compound may be used in combination.

In the present invention, an important point in the radiation-shielding molding material as a composition having the lead particles and/or lead compound and a polymer is the content ratio of the lead particles and/or lead compound (lead particles and/or The content ratio of the lead compound and the polymer relative to the total amount is 5 to 80% by weight, particularly 20 to 80% by weight.

The content of lead particles and/or lead compounds is 5 to 8.
When the amount is within the range of 0% by weight, the radiation-shielding molding material has a large radiation-shielding effect, particularly electron beams and gamma rays, and the deterioration of the mechanical strength of the radiation-shielding molding material due to radiation is extremely small.

Conversely, if the content is less than 5% by weight, the radiation shielding effect will be poor, while if it exceeds 80% by weight, the material will become brittle.

As explained above, this radiation-shielding molding material has excellent radiation-shielding properties and radiation resistance by containing a specific polymer and a specific blending ratio of lead particles and/or lead compounds. However, other components may be included as long as they do not impede the purpose of the present invention and depending on the intended use.

Other components include 1, for example, other types of thermoplastic resins,
Examples include a thermosetting resin, an antioxidant, an ultraviolet absorber, a flame retardant, an antistatic agent, a lubricant, a colorant, and a surface treatment agent.

Furthermore, when other components such as graphite, boron oxide, boron carbide, and boron-containing ore are blended, it is effective for shielding neutrons.

This radiation-shielding molding material can be prepared by a mixing crosstalk method.

For example, a method of premixing all components and kneading this premix with the remaining components, or a method of blending the polymer and lead and/or a lead compound, then adding other optional components, and then kneading the premix with the remaining components; Examples include a method of mixing or kneading.

The mixing or kneading may be carried out using, for example, a ribbon blender.
This can be carried out using a tumble mixer, a Henschel mixer, an oven roll, a panburi mixer, a Henschel mixer, a single screw extruder, a two-screw single extruder, a single reciprocating screw mixer, or the like.

The radiation-shielding molding material thus obtained is molded into various molding amounts by various molding methods such as injection molding, press molding, and extrusion molding.

[Example] Next, an example of the present invention will be shown and the present invention will be explained in more detail.

(Example 1) 4.4°-bis(2,
3-dicarboxyphenoxy)biphenyl sialic acid anhydride 7
1.76 g (0.15 mol), benzidine 27.64
g (0.15 mol), dimethylacetamide 700
Add mJ1 and bring to room temperature while blowing argon gas.
The reaction was allowed to take place for 120 minutes.

7 ml of this solution was sampled and reprecipitated in methanol.

The reduced viscosity of the obtained polyamic acid was measured in N-methyl-2-pyrrolidone at 30 DEG C. at a concentration of 0.5 g/d, and it was found to be 0.5 dJl/g.

This polyamic acid was confirmed to have the following structural unit based on the results of infrared absorption spectrum analysis.

Next, this solution was subjected to a ring-closing reaction for 3 hours while being heated to 170''C.

After the reaction was completed, the product was poured into methanol to separate the polymer.

The yield of the obtained polymer was 92.5 g.

The thus obtained polymer was hot pressed at a temperature of 380°C to produce a film with a thickness of 200 microns.

After this film was irradiated with an electron beam of 21 megaplays per hour (MGy) at the dose shown in Table 1, a 4-layer test was conducted.

Tensile test is based on ASTIII D882 (the same applies below)
It was measured by

The results are shown in Table 1.

(Comparative Example 1) Polyetheretherketone resin film (PEE
K) [Manufactured by ICI: Victrex ■450G] The tensile strength after electron beam irradiation was measured in the same manner as in Example 1.

The results are shown in Table 1.

(Comparative Example 2) A tensile test was conducted using an aromatic polyimide resin film [Kapton ■ manufactured by DuPont] by irradiating it with an electron beam in the same manner as in Example 1.

The results are shown in Table 1.

(Example 2) The polymer produced in Example 1 was mixed into a glass fiber mat (
(manufactured by Nippon Sheet Glass) at a weight ratio of 1:1 at 400°
A sheet having a thickness of about 1 liter was prepared by impregnation using a heat press of C.

Using this sheet, a tensile test was conducted in the same manner as in Example 1 after irradiation with an electron beam at the dose shown in Table 2.

The results are shown in Table 2.

(Comparative Example 3) A tensile test was conducted in the same manner as in Example 2, except that a PEEK film (polyetheretherketone resin) manufactured by IC1 was used and impregnated with glass fiber.

The results are shown in Table 2.

(Example 3) The polyetherimide produced in Example 1 was
A weight ratio of 1. 40 in l proportion
A sheet having a thickness of about 1 inch was prepared by impregnation using a hot press at 0°C.

Using this sheet, a tensile test was conducted in the same manner as in Example 1 after irradiation with an electron beam at the dose shown in Table 3.

The results are shown in Table 3.

(Comparative Example 4) A tensile test was conducted in the same manner as in Example 3 using a film (polyetheretherketone resin) on PEE manufactured by ICI.

The results are shown in Table 3.

(Examples 4 to 6 and Reference Example 1.2) The polymer produced in Example 1 was blended with the lead compounds shown in Table 4 to prepare a sheet having a thickness of lam.

This sheet was used to measure bending strength and radiation shielding properties.

The results are shown in Table 4.

Table: Polyetheretherketone resin (manufactured by IC1) Aromatic polyester resin (manufactured by DuPont) Table ◎: Very good shielding property, Q, A hostility υ>! , A radiation-resistant molding material can be provided.

(2) Also, according to the invention of claim 2, it includes a polymer, lead particles, and/or a lead compound. A radiation-shielding molding material with excellent radiation resistance can be provided.

Claims (3)

[Claims] (1) The following formula (I): ▲There are mathematical formulas, chemical formulas, tables, etc.▼ A radiation-resistant molding material characterized by containing a polymer having a repeating unit represented by (I). (2) A radiation-shielding molding material containing the polymer according to claim 1 and lead and/or a lead compound. (3) The content ratio of the lead and/or lead compound is 5 to 5.
The radiation-shielding molding material according to claim 1, which is 80% by weight.