JPH0622587B2 - Polycarbonate medical moldings for irradiation sterilization - Google Patents

Description

TECHNICAL FIELD The present invention relates to a medical polycarbonate molded article having excellent radiation resistance. Since the polycarbonate molded article of the present invention is substantially free from yellowing due to radiation irradiation in the absence of oxygen, it is useful as a medical device for radiation irradiation sterilization in the absence of oxygen.

[Conventional technology and its problems]

Aromatic polycarbonate resins have high impact resistance, heat resistance, transparency, and high safety, and are therefore widely used as medical products.

When used in these medical products, high pressure steam sterilization and ethylene oxide gas (EOG) sterilization have been conventionally performed. However, the steam sterilization method has drawbacks in that it cannot be completely sterilized or that a drying step is required after the sterilization processing. In addition, the EOG sterilization has problems such as toxicity of EOG remaining in the material to be sterilized.

Therefore, recently, a sterilization method of irradiating radiation (generally γ-ray) which can be performed in a dry method at a relatively low temperature at a low temperature has been attracting attention, and in order to prevent bacterial growth, the product is substantially sterilized. In addition, sterilization under anoxic conditions has also been attracting attention.

However, when a molded article made of a polycarbonate resin which has been conventionally used for these purposes is irradiated with radiation, the resin is decomposed to cause yellowing, thus degrading the product value. Furthermore, this tendency was significantly increased when the treatment was carried out substantially in the absence of oxygen.

[Means for Solving the Problems]

As a result of intensive studies to develop a medical product made of a polycarbonate resin suitable for sterilization by irradiation, the present inventors have found that an aromatic polycarbonate containing a structural unit derived from a halogenated bisphenol in its molecular chain is used. It has been found that the molded product used can solve this problem.
Furthermore, they have found that the molded article is less colored when irradiated with radiation substantially in the absence of oxygen, and completed the present invention.

That is, the present invention is directed to radiation sterilization under an atmosphere substantially free of oxygen, which comprises an aromatic polycarbonate resin containing an aromatic polycarbonate polymer or oligomer containing a structural unit derived from a halogenated bisphenol in a molecular chain. Polycarbonate medical molded article for radiation irradiation sterilization, which is an aromatic polycarbonate resin having a halogen content of 0.1 to 10% by weight, more preferably 0.5 to 5% by weight. It is a product.

The configuration of the present invention will be described below.

First, the aromatic polycarbonate polymer or oligomer containing a constitutional unit derived from a halogenated bisphenol in the molecular chain of the present invention is produced by using a halogenated bisphenol as a part or all of a dihydric phenol itself. The conventionally known ones, which are preferably used in the present invention, include (a). Aromatic polycarbonate copolymers using halogenated bisphenols as part of the dihydric phenol, (b). Aromatic polycarbonate homo-oligomer using halogenated bisphenol as dihydric phenol, (c). Aromatic polycarbonate co-oligomers using halogenated bisphenols as a part of the dihydric phenol can be mentioned. In order to prevent discoloration due to radiation irradiation,
Halogenated bisphenols are also effective, but are not very preferable for the use of the present invention in that they have low thermal stability and have a large elution possibility due to their low molecular weight.

The aromatic polycarbonate resin of the present invention is not particularly limited as long as it contains an aromatic polycarbonate polymer or oligomer containing a structural unit derived from the above halogenated bisphenol in the molecular chain,
In particular. Above (a) alone ,. Above (a) and above
a composition with aromatic polycarbonate oligomers derived from (b), (c) or a halogen-free dihydric phenol ,. Aromatic polycarbonate resin derived from a halogen-free dihydric phenol and the above (a), (b) or
The composition with (c) is mentioned.

Here, the above-mentioned aromatic polycarbonate polymer or oligomer used in the present invention is produced by a known production method, and as the halogenated bisphenol, bis (4-hydroxy-3,5-dibromophenyl) methane,
2,2-bis (4-hydroxy-3,5-dibromophenyl)
Propane, 4,4'-dihydroxy-3,3 ', 5,5'-tetrabromodiphenyl sulfide, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4- Examples include hydroxy-3-bromophenyl) propane, bis (4-hydroxy-3-chlorophenyl) methane, bis (4-hydroxy-3.5-dichlorophenyl) methane and bis (4-hydroxy-3-bromophenyl) methane. Halogen-free dihydric phenols include bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, bis (4-hydroxyphenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxy). Phenyl)
Sulfide, bis (4-hydroxyphenyl) ketone,
1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-
Hydroxyphenyl) cyclohexane, 2,2-bis (4
-Hydroxy-3,5-dimethylphenyl) propane, 1,1
Examples include -bis (4-hydroxyphenyl) -1-phenylethane and bis (4-hydroxyphenyl) diphenylmethane. In addition, the terminal stopper (molecular weight regulator) is
Long-chain alkyl-substituted phenols such as octylphenol, nonylphenol, laurylphenol, palmitylphenol, stearylphenol, etc. in addition to ordinary phenol, pt-butylphenol, tribromophenol; octyl hydroxybenzoate, lauryl hydroxybenzoate, hydroxybenzoate Hydroxybenzoic acid long-chain alkyl esters such as nonyl acid and stearyl hydroxybenzoate; octyl ether phenol (= octyloxyphenol), nonyl ether phenol, lauryl ether phenol, palmityl ether phenol, octadecyloxyphenol, dodecyloxyphenol, etc. Long-chain alkyloxyphenols; capric chloride, lauryl chloride, myristic chloride, palmitic acid Roraido, stearic acid chloride, such as aliphatic acid chloride such as cerotic acid chloride are exemplified.

Further, an aromatic polycarbonate polymer or oligomer containing or not containing a constitutional unit derived from a halogenated bisphenol in the molecular chain of the present invention is produced by using the above components, but the branching agent is It is also possible to use a branched polycarbonate in a range of 0.01 to 3 mol, particularly 0.1 to 1.0 mol, per 100 mol of the dihydric phenol compound. As such a branching agent,
Phloroglysin, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3,4,6-dimethyl-2,
4,6-tri (4-hydroxyphenyl) heptene-2,
1,3,5-tri (2-hydroxyphenyl) benzol,
1,1,1-tri (4-hydroxyphenyl) ethane, 2,6-
Polyhydroxy compounds exemplified by bis (2-hydroxy-5-methylbenzyl) -4-methylphenol, α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, etc. And 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chloroisatin, 5,7-dichloroisatin, 5-bromoisatin and the like.

Polycarbonate for irradiation sterilization of the present invention: Polycarbonate resin preferably used for producing a molded article for medical use includes (1), 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A) and 2,2 -Copolymerized polycarbonate resin with bis (4-hydroxy-3,5-dibromophenyl) propane (= tetrabromobisphenol A), (2), composition of bisphenol A polycarbonate resin and copolymerized polycarbonate resin of (1) above Thing, (3),
Bisphenol A polycarbonate resin and pt at the end
Examples include a composition of a polycarbonate oligomer of tetrabromobisphenol A blocked with butylphenol, tribromophenol, or the like, or a copolymerized polycarbonate oligomer of bisphenol A and tetrabromobisphenol A blocked with ends. The content of halogen atoms in the present molded article for medical treatment is not preferable because it is not effective in suppressing yellowing due to irradiation when it is too small, and mechanical properties and heat resistance are deteriorated when it is too large. The amount of halogen atoms in the molded article for medical treatment is 0.1 to 10% by weight, preferably
It is selected from the range of 0.5 to 5% by weight.

The conditions for producing the polycarbonate medical molded article for irradiation sterilization of the present invention by molding the above aromatic polycarbonate resin, the viscosity average molecular weight of the aromatic polycarbonate resin used, the type of dihydric phenol used,
Although it varies depending on the type of the terminal stopper, the content of halogenated bisphenol, etc., it is usually produced by injection molding at 260 to 340 ° C.

The present invention is as described above, when adjusting the molding material, if necessary, a heat stabilizer, an antioxidant, a colorant,
Various additives such as a lubricant and a release agent can be added.

〔Example〕

Hereinafter, specific examples will be described with reference to synthesis examples, examples, and comparative examples. In addition, "%" and "part" in Examples and the like are based on weight unless otherwise specified.

Synthetic Example 1 8.1 kg of bisphenol A (hereinafter referred to as BPA) and tetrabromobisphenol A (hereinafter referred to as TBA) were placed in a 100 reaction vessel.
750 g, a 9% aqueous solution of caustic soda 42, and methylene chloride (hereinafter referred to as MC) 30 were added, and 4.2 kg of phosgene was blown in for 30 minutes while maintaining the temperature at about 20 ° C under stirring.

Then, 209 g of p-tert-butylphenol (hereinafter referred to as PTBP) dissolved in MC2 and 7 m of triethylamine (hereinafter referred to as TEA) were added, and stirring was continued for about 1 hour for polymerization.

The polymerization solution was separated into an aqueous phase and an organic phase, the organic phase was neutralized with phosphoric acid, and the aqueous solution was repeated until the washing pH became neutral, and then 35 isopropanol was added to precipitate the polymer. It was The precipitate was filtered and then dried to obtain a white powdery polycarbonate copolymer (hereinafter referred to as CPC1).

The viscosity average molecular weight of CPC1 was 25,000, and the bromine (Br) content calculated from the amount of reaction monomers after polymerization was 4.46%.

Synthesis Example 2 TBA 9 kg, 9% sodium hydroxide aqueous solution 30, water 10, MC23, TBA 6 ml were put in a reaction vessel of 100, and 2.5 kg of phosgene was added to 30 while keeping the temperature at about 20 ° C. under stirring.
Blown in minutes.

Then, 970 g of PTBP dissolved in MC10 and 50 ml of TEA were added, and stirring was continued for about 1 hour to polymerize.

Then, after purifying the organic layer in the same manner as in Synthesis Example 1, the solvent was evaporated from the organic layer to dryness, and a white powdery polycarbonate homo-oligomer having an average degree of polymerization of 5 and a Br content of 50.3% (hereinafter referred to as HOPC2 and Note) was obtained.

Synthesis Example 3 TBA 9.8 kg, water 30, MC37, 9% in 100 reaction vessel
Add caustic soda aqueous solution 4 and 4.9 g of triethylbenzylammonium chloride, and stir to adjust the pH of this mixture to 1
1.0-11.8, while maintaining the temperature at about 20 ℃, phosgene 3.8kg
Was blown in 30 minutes. The pH was adjusted by adding a 35% aqueous sodium hydroxide solution.

Then, the reaction mixture was transferred to 150 reaction vessels, and 9% sodium hydroxide aqueous solution 19, BPA 2.2 kg, PTBP 1.65 kg were added.
A solution prepared by dissolving 15 in MC was added, and further 450 g of TEA was added, and stirring was continued for about 1 hour for polymerization.

Then, in the same manner as in Synthesis Example 2, a white powdery polycarbonate co-oligomer having an average degree of polymerization and a Br content of 39.7% (hereinafter referred to as COPC3) was obtained.

Examples 1 to 5 and Comparative Example 1 The copolycarbonate resin obtained alone in Synthesis Example 1 or an aromatic polycarbonate resin (trade name; Iupilon S-3000,
Mitsubishi Gas Chemical Co., Ltd.) and the polycarbonate polymers or oligomers obtained in Synthesis Examples 1 to 3 were mixed in a tumbler at a ratio shown in Table 1, and each was extruded with a uniaxial vented extruder to obtain pellets. .

An injection molding machine (Sumitomo Heavy Industries, Ltd.)
Made; Neomat 110/45) with resin temperature 300 ℃, mold temperature 80 ℃, injection pressure 1,200kg / cm ² 50 × 60mm, thickness 3.
A 2 mm molded piece was molded.

Using this molded piece, a sealed product (deoxygenated) in air and molded product together with a deoxidizer (trade name; Ageless, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used to irradiate each with 2.5 megarads of γ-rays. The change (ΔYI) in the degree of yellowing (YI) was measured with a color difference meter SM-3-CH manufactured by Suga Test Instruments Co., Ltd. The results are shown in Table 1.

[Operations and Effects of the Invention] As described above, a molded article using the aromatic polycarbonate resin containing the structural unit derived from the halogenated bisphenol of the present invention is, of course, in the air, particularly, substantially oxygen-free. Less yellowing under γ-ray irradiation.

Therefore, it is useful as a case for artificial dialysis machines, artificial lungs, blood transfusion sets, etc. for radiation sterilization (generally γ-ray sterilization).

Claims (3)

[Claims] 1. Radiation irradiation sterilization in an atmosphere substantially free of oxygen, which comprises an aromatic polycarbonate polymer containing an aromatic polycarbonate polymer or oligomer containing a structural unit derived from a halogenated bisphenol in its molecular chain. Polycarbonate medical moldings. 2. A polycarbonate medical molded article for irradiation irradiation sterilization according to claim 1, wherein the halogen content of the aromatic polycarbonate resin is 0.1 to 10% by weight. 3. The polycarbonate medical molded article for radiation irradiation sterilization according to claim 1, wherein the halogen content of the aromatic polycarbonate resin is 0.5 to 5% by weight.