JP2001270980A - Ionizing radiation stabilized polycarbonate resin composition and polycarbonate resin composition for part of medical equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polycarbonate resin composition and a polycarbonate resin composition for pants of medical equipment which have reduced deterioration of properties and extremely reduced yellowing upon ionizing radiation sterilization. SOLUTION: The ionizing radiation stabilized polycarbonate resin composition and the polycarbonate resin composition for parts of medical equipment comprise 100 pts.wt. polycarbonate resin and 0.001-20 pts.wt. acetal compound represented by formula (1) (wherein m and n are each an integer of 0-5; R1 and R2 may be the same or different and each at least one group selected from the group consisting of 1-18C alkyl group, a 1-18C alkoxy group, a 1-18C acyl group, a 1-18C acyloxy group, and a 2-8C polyoxy hydrocarbon group).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polycarbonate resin composition comprising a polycarbonate resin and a specific acetal compound having a benzal structure, and a polycarbonate resin composition for a member of a medical device. More specifically, the present invention relates to a polycarbonate resin composition stabilized against ionizing radiation used for sterilization treatment of a medical instrument and a polycarbonate resin composition for a member of a medical instrument.

[0002]

2. Description of the Related Art Polycarbonate resin has mechanical strength,
It is widely used as a thermoplastic resin with excellent transparency, heat resistance and impact resistance. Due to such excellent properties, the resin is particularly suitable for containing and packaging syringes, surgical tools, surgical instruments, etc., artificial lungs, artificial kidneys, anesthesia absorbing devices,
It is used as a member of various medical instruments such as intravenous connectors and accessories, medical devices such as blood separation devices, surgical tools, and surgical tools.

[0003] In these medical applications, complete sterilization is usually performed. Examples of the sterilization treatment include an ethylene oxide gas contact treatment, a high-temperature and wet heat treatment using high-pressure steam in an autoclave, and a treatment of ionizing radiation such as γ-ray and electron beam. Among them, the ethylene oxide method is not preferred because it has problems of safety of the gas itself, toxicity (especially carcinogenicity, etc.), problems of residual gas in the medical device to be treated, and environmental problems related to disposal. The steam sterilization method has problems such as deformation of the material due to high temperature and humidity heat treatment, deterioration due to hydrolysis, and high processing cost, and further requires a drying step after the sterilization treatment. On the other hand, the ionizing radiation treatment method has the advantages that there is no problem of remaining in the product, the treatment can be performed in a dry state at a low temperature, the treatment cost is relatively low, and the like. Since it can be sterilized, it has been widely used.

However, when the polycarbonate resin is irradiated with such ionizing radiation, the polycarbonate resin changes its color to yellow with a chemical change. This discoloration significantly impairs commercial value, such as the inability to see the correct color tone of the contents in medical applications.

Various attempts have been made to prevent such yellowing. For example, there is known a method of adding a bluish colorant to a resin to cancel the yellow tint. However, in such a method, although the yellow tint can be eliminated by the amount of the coloring agent added, the color becomes darker as a whole, and the commercial value is also impaired.

A method of adding a polyether polyol or an alkyl ether thereof is also known (Japanese Patent Application Laid-Open No. 62-135556). Such a method provides some improvement but is still insufficient, and there is a problem that the addition of the compound easily causes decomposition of the polycarbonate resin and burns during molding.

Further, a method of adding an aromatic halogen compound has been disclosed (JP-A-2-129261). This method gives a rather good stabilizing effect on the polycarbonate resin, but it is a halogen compound,
There is the problem that environmental issues related to safety and disposal cannot be avoided.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polycarbonate resin composition which causes little deterioration in physical properties and has a very small yellowing upon ionizing radiation sterilization, and a polycarbonate resin composition for a member of a medical instrument. It is in. The present inventor has conducted intensive studies to achieve the object, and as a result, by adding a specific acetal compound having a benzal structure to a polycarbonate resin, yellowing upon ionizing radiation sterilization becomes extremely small. The inventors have found that the present invention has been achieved.

[0009]

According to the present invention, an ionizing radiation-stabilized polycarbonate resin composition comprising 100 parts by weight of a polycarbonate resin and 0.001 to 20 parts by weight of an acetal compound represented by the following formula (1): Is provided.

[0010]

Embedded image

(Wherein m and n are integers from 0 to 5; R ¹ and R ² may be the same or different; each represents a hydrocarbon group having 1 to 18 carbon atoms; At least one group selected from the group consisting of a hydrocarbon oxy group, an acyl group having 1 to 18 carbon atoms, an acyloxy group having 1 to 18 carbon atoms, and a polyoxyhydrocarbon group having 2 to 8 carbon atoms.)

The polycarbonate resin used in the present invention includes various aromatic dihydroxy compounds or an interfacial polycondensation method in which a small amount of the polyhydroxy compound is reacted with phosgene, or a diphenyl carbonate or the like. It is a polymer or copolymer of an optionally branched thermoplastic aromatic polycarbonate synthesized by a melt polymerization method of reacting with a carbonate ester. A typical example is 2,2-bis (4
-Hydroxyphenyl) propane (bisphenol A)
And polycarbonate synthesized from the following.

The aromatic dihydroxy compound includes:
Bisphenol A, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane,
2,2-bis (4-hydroxyphenyl) octane, bis (4-hydroxyphenyl) phenylmethane, 2,2
-Bis (4-hydroxy-3-methylphenyl) propane, 2,2-bis (4-hydroxy-3-tert-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4
-Hydroxy-3,5-dibromophenyl) propane,
2,2-bis (4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis (4-hydroxy-3,
5-dimethylphenyl) propane, 2,2-bis (3-
Phenyl-4-hydroxyphenyl) propane, 2,2
-Bis (3-cyclohexyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, 9,9-bis (4-hydroxyphenyl) ) Fluorene, 9,9-bis (4-hydroxy-3-methylphenyl) fluorene, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-
Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 1,1-bis (4-hydroxyphenyl) cyclopentane, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3 , 3'-
Dimethyldiphenyl ether, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-diphenyl sulfide, 4, 4'-dihydroxy-3,3'-
Diphenylsulfoxide, 4,4'-dihydroxy-
3,3'-diphenylsulfone, 1,3-bis {2-
(4-hydroxyphenyl) propyl @ benzene, 1,
4-bis {2- (4-hydroxyphenyl) propyl}
Benzene, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl and the like;
Is preferably used. These compounds can be used alone or in combination of two or more.

In order to obtain a branched aromatic polycarbonate resin, phloroglysin, 2,6-dimethyl-
2,4,6-tris (4-hydroxyphenyl) -3-
Heptene, 4,6-dimethyl-2,4,6-tris (4
-Hydroxyphenyl) -2-heptene, 1,3,5-
Tris (2-hydroxyphenyl) benzol, 1,
1,1-tris (4-hydroxyphenyl) ethane,
2,6-bis (2-hydroxy-5-methylbenzyl)
-4-methylphenol, α, α ′, α ″ -tris (4
-Hydroxyphenyl) -1,3,5-triisopropylbenzene, 3,3-bis (4-hydroxyphenyl)
Oxyindole (isatin bisphenol), 5-chloroisatin bisphenol, 5-bromoisatin bisphenol, 5,7-dichloroisatin bisphenol may be used.

The reaction by the interfacial polycondensation method is usually a reaction between dihydric phenol and phosgene, and is carried out in the presence of an acid binder and an organic solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used.
As the organic solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. Further, for promoting the reaction, for example, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide, or tetra-n-butylphosphonium bromide, a quaternary ammonium compound, or a quaternary phosphonium compound may be used. it can. At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

In such a polymerization reaction, a terminal stopper is usually used. Monofunctional phenols can be used as such a terminal stopper. Monofunctional phenols are commonly used as molecular terminators for molecular weight control, and the resulting polycarbonate resins are capped by groups based on monofunctional phenols, so that Excellent heat stability. Specific examples of such monofunctional phenols include, for example, phenol, p-tert-butylphenol, p-cumylphenol and isooctylphenol. Further, as other monofunctional phenols, phenols or benzoic acid chlorides having a long-chain alkyl group or aliphatic polyester group as a substituent, or long-chain alkyl carboxylic acid chlorides can be used.

It is desirable that these terminal stoppers are introduced at least at 5 mol%, preferably at least 10 mol%, based on all terminals of the obtained polycarbonate resin. Or a mixture of two or more.

The reaction by the melt polymerization method is usually a transesterification reaction between a dihydric phenol and a carbonate ester. The dihydric phenol and the carbonate ester are mixed while heating in the presence of an inert gas to form an alcohol. Alternatively, it is carried out by a method of distilling phenol. The reaction temperature varies depending on the boiling point of the produced alcohol or phenol, but is usually in the range of 120 to 350 ° C. In the latter half of the reaction, the pressure of the system is reduced to about 10 to 0.1 Torr to facilitate the distillation of the alcohol or phenol produced. The reaction time is usually about 1 to 4 hours.

Examples of the carbonate ester include an optionally substituted ester such as an aryl group having 6 to 15 carbon atoms, an aralkyl group or an alkyl group having 1 to 4 carbon atoms. Specifically, diphenyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl)
Examples thereof include carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Among them, diphenyl carbonate is preferable.

A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include sodium hydroxide, potassium hydroxide, alkali metal compounds such as sodium and potassium salts of dihydric phenol, and water. Alkaline earth metal compounds such as calcium oxide, barium hydroxide and magnesium hydroxide; nitrogen-containing basic compounds such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, trimethylamine and triethylamine; alkoxides of alkali metals and alkaline earth metals Manganese, organic acid salts of alkali metals and alkaline earth metals, zinc compounds, boron compounds, aluminum compounds, silicon compounds, germanium compounds, organic tin compounds, lead compounds, osmium compounds, antimony compounds Compounds, titanium compounds, usually the esterification reaction, such as zirconium compounds, there can be used a catalyst used in the transesterification reaction. The catalyst may be used alone or in combination of two or more. The amount of the polymerization catalyst used is preferably 1 × 10 ⁻⁹ to 1 × 1 with ^respect to 1 mol of the dihydric phenol as the raw material.
It is selected in the range of 0 ^-3 equivalents, more preferably 1 × 10 ^{-8 to} 5 × 10 ^-4 equivalents.

The polycarbonate resin has a viscosity average molecular weight (M) of preferably 10,000 to 100,000, more preferably 11,000 to 45,000, and
000 to 30,000 are particularly preferred. A polycarbonate resin having such a viscosity average molecular weight is preferable because sufficient strength is obtained, the melt fluidity during molding is good, and molding distortion does not occur. The viscosity average molecular weight of 0.7 g of polycarbonate resin in 100 ml of methylene chloride is 2
The specific viscosity (η _sp ) obtained from the solution dissolved at 0 ° C. was obtained by inserting it into the following equation. η _sp /c=[η]+0.45×[η] ² c (where [η]
Is the intrinsic viscosity) [η] = 1.23 × 10 ⁻⁴ M ^0.83 c = 0.7

The acetal compound used in the present invention is an acetal compound represented by the above formula (1),
In the formula (1), m and n are an integer of 0 to 5, preferably an integer of 0 to 2, R ¹ and R ² may be the same or different, and have 1 to 18 carbon atoms. Hydrocarbon group, C1-C18 hydrocarbonoxy group, C1
And at least one group selected from the group consisting of an acyl group having 1 to 18 carbon atoms, an acyloxy group having 1 to 18 carbon atoms and a polyoxyhydrocarbon group having 2 to 8 carbon atoms.

The hydrocarbon group having 1 to 18 carbon atoms is an alkyl group, aralkyl group or aryl group having 1 to 18 carbon atoms, preferably 1 to 15 carbon atoms, and specifically, methyl, ethyl, butyl , Iso-butyl, ter
t-butyl, octyl, nonyl, decyl, octadecyl, benzyl, phenyl and the like.

The hydrocarbon oxy group having 1 to 18 carbon atoms is an alkyloxy group, an aralkyloxy group or an aryloxy group having 1 to 18 carbon atoms, preferably 1 to 15 carbon atoms. , Butoxy, octyloxy, stearyloxy, lauryloxy, phenoxy, benzyloxy and the like.

Specific examples of the acyl group having 1 to 18 carbon atoms include acetyl, propionyl, butyryl, stearoyl, lauroyl, benzoyl and the like.

The acyloxy group having 1 to 18 carbon atoms includes
Specific examples include acetoxy, propionyloxy, butyryloxy, stearoyloxy, benzoyloxy and the like.

Specific examples of the C 2-8 polyoxyhydrocarbon group include ethoxyethoxy and benzyloxyethoxy.

As the acetal compound represented by the above formula (1), specifically, 3,9-diphenyl-2,4,4
8,10-tetraoxaspiro [5,5] undecane,
3- (4-methylphenyl) -9-phenyl-2,4,
8,10-tetraoxaspiro [5,5] undecane,
3,9-bis (2-methylphenyl) -2,4,8,1
0-tetraoxaspiro [5,5] undecane, 3,9
-Bis (3-methylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-methylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2,
4-dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2,
5-dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2,
6-dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (3,
5-dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane,

3,9-bis (4-iso-butylphenyl) -2,4,8,10-tetraoxaspiro [5
5] Undecane, 3- (4-ethylphenyl) -9-
(4-butylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-
tert-butylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-octylphenyl) -2,4,8,10-tetraoxaspiro [5, 5] undecane, 3,9-bis (4
-Nonylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-decylphenyl) -2,4,8,10-tetraoxaspiro [5,5 ] Undecane, 3,9-bis (4-dodecylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-octadecylphenyl) -2,4,8 , 10-Tetraoxaspiro [5,5] undecane, 3,9-bis (4-phenylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane,

3,9-bis (4-methoxyphenyl)-
2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-butoxyphenyl) -2,
4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-benzyloxyphenyl)-
2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-acetylphenyl) -2,
4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis {4- (ethoxyethoxy) phenyl} -2,4,8,10-tetraoxaspiro [5,
5] undecane and 3,9-bis {4- (benzyloxyethoxy) phenyl} -2,4,8,10-tetraoxaspiro [5,5] undecane.

Among these, 3,9-diphenyl-2,2
4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2-methylphenyl) -2,4
8,10-tetraoxaspiro [5,5] undecane,
3,9-bis (3-methylphenyl) -2,4,8,1
0-tetraoxaspiro [5,5] undecane, 3,9
-Bis (4-methylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2,4-dimethylphenyl) -2,4,8,10-tetra Oxaspiro [5,5] undecane, 3,9-bis (2,5-dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-iso -Butylphenyl) -2,4,8,10-
Tetraoxaspiro [5,5] undecane and 3,9
-Bis (4-phenylphenyl) -2,4,8,10-
Tetraoxaspiro [5,5] undecane is preferred,
In particular, 3,9-diphenyl-2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (3
-Methylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (2,4-
Dimethylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane, 3,9-bis (4-is
o-butylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane and 3,9-bis (4
-Phenylphenyl) -2,4,8,10-tetraoxaspiro [5,5] undecane is preferred. These acetal compounds can be used alone or in combination of two or more.

The acetal compound of the above formula (1) is prepared by diluting pentaerythritol and a corresponding benzaldehyde derivative with an organic solvent not involved in the reaction, if necessary, and subjecting the acetal compound to a condensation reaction in the presence of an acid catalyst. Usually, it can be obtained by reacting at a temperature of 0 ° C. to 120 ° C. for 30 minutes to 15 hours. Examples of the acid catalyst include organic acids such as toluenesulfonic acid, benzenesulfonic acid, and methylsulfonic acid, and inorganic acids such as sulfuric acid, hydrochloric acid, and nitric acid. Examples of the organic solvent include hydrocarbon compounds such as benzene, toluene, and cyclohexane; dioxane; ether compounds such as 1,2-dimethoxyethane; chlorobenzene;
Halogenated hydrocarbon compounds such as 2-dichloroethane are exemplified. The acetal compound of the present invention can be obtained from the reaction mixture after the above condensation reaction by general separation means. For example, filtration from the reaction mixture, or crystallization from the organic layer after adding water to the reaction mixture to remove the acid catalyst,
It can be obtained by evaporating the solvent.

In the present invention, the acetal compound has an effect of suppressing deterioration of the polycarbonate resin due to irradiation with ionizing radiation, and can be used as a stabilizer for ionizing radiation of the polycarbonate resin.

In the present invention, the polycarbonate resin 1
The acetal compound represented by the formula (1) is in the range of 0.001 to 20 parts by weight with respect to 00 parts by weight.
The range is preferably from 01 to 5 parts by weight, more preferably from 0.1 to 3 parts by weight. When the amount is less than 0.001 part by weight, the effect of stabilizing ionizing radiation is insufficient, and when the amount is more than 20 parts by weight, the physical properties of the polycarbonate resin may be impaired or the cost may be disadvantageous. Absent.

The acetal compound can be used in combination with other conventionally known stabilizers against ionizing radiation, and such a combination may provide a synergistic stabilizing effect. Examples of such compounds include polyalkylene glycols such as polypropylene glycol, thioether compounds described in JP-A-2-115260, and compounds having a mercapto group described in JP-A-6-166807. JP-A-8-225732, JP-A-8-225733, JP-A-8-225
No. 734, benzyl ethers, ethers having a benzyloxy structure such as benzyl alcohol, alcohol compounds, and sulfur compounds having a benzylthio structure such as benzyl sulfide. The amount of these stabilizers used is 100% of polycarbonate resin.
It is usually used in the range of 0.001 to 15 parts by weight based on part by weight.

The polycarbonate resin composition of the present invention contains other resin materials and other components to such an extent that the effects of the present invention are not impaired.
For example, polyethylene terephthalate, polybutylene terephthalate, polyester polycarbonate, polyarylate, a polyester of cyclohexane dimethanol with terephthalic acid and / or isophthalic acid, a copolyester of polyethylene terephthalate, or the like can be used as a mixture. Usually, it is used in an amount of 30 parts by weight or less with respect to 100 parts by weight of the polycarbonate resin in consideration of the transparency and physical properties of the polycarbonate resin composition.

The polycarbonate resin composition of the present invention contains various additives generally used for polycarbonate resins, for example, higher fatty acids such as stearic acid and palmitic acid for improving the moldability. Glycerin, trimethylolpropane, esters or partial esters with alcohols such as pentaerythritol, release agents such as paraffin, heat stabilizers such as phosphate esters and phosphites, and antioxidants such as hindered phenols, Weather resistance improver, ultraviolet absorber, flame retardant, flame retardant auxiliary, impact resistance improver, antistatic agent, plasticizer, lubricant, compatibilizer, foaming agent,
Reinforcing agents, fillers, coloring agents such as dyes and pigments, and the like can be compounded within a range that does not adversely affect irradiation with ionizing radiation.

The polycarbonate resin composition of the present invention comprises:
Any of commonly used molding methods such as injection molding, extrusion molding, blow molding, compression molding, transfer molding and the like can be applied. Among them, the injection molding method is preferably used, and it cannot be said unconditionally because it varies depending on the type of the polycarbonate resin, the degree of polymerization, the type and the amount of the acetal compound, the type and the amount of other additives, and the like. But usually 26
Molded at 0-350 ° C.

The molded product thus obtained is obtained by using an electron beam, γ
It has high stability against ionizing radiation such as X-rays, α-rays, neutron rays, and X-rays, and is particularly suitable for members of medical instruments that use γ-rays or electron beams for sterilization.

The members of such medical instruments include artificial dialysers (cases and caps for artificial kidneys), artificial lungs, anesthesia inhalers, intravenous connectors and accessories, blood centrifuge bowls, surgical tools, operating rooms Utensils, tubes for supplying oxygen to the blood, tube connections, heart probes and syringes,
Examples include surgical tools, operating room instruments, containers for storing intravenous injections, and the like.

[0041]

The present invention will be described in more detail with reference to the following examples, but it should not be construed that the invention is limited thereto. In Examples, parts and percentages are by weight unless otherwise specified.

[Synthesis of Acetal Compound] 212.2 g (2.0 mol) of benzaldehyde, 136.1 g (1.0 mol) of pentaerythritol, 600 m of toluene
l into a 1-liter eggplant flask equipped with a magnetic stirrer, Dean Stark, and a reflux condenser, and 3.8 g (0.02 mol) of p-toluenesulfonic acid monohydrate was added.
Was added. Next, the mixture was heated to reflux of toluene and reacted for 6 hours, and then 300 ml of toluene was distilled off over 3 hours. After cooling to room temperature, methylene chloride was added to dissolve the precipitated colorless solid and washed with water until neutral. After evaporating the solvent, the obtained colorless solid was recrystallized from a mixed solution of ethanol / methylene chloride to give 3,9-diphenyl-2,
4,8,10-Tetraoxaspiro [5,5] undecane (compound in the above formula (1), wherein m and n are 0) 273
g (88% yield) as colorless scaly crystals (melting point:
159-160 ° C). The compound was identified using a ¹ H-NMR spectrum and an IR spectrum.

In addition, a similar compound was used in place of benzaldehyde and synthesized in the same manner to obtain the following compound. 3,9-bis (3-methylphenyl) -2,4,8,
10-tetraoxaspiro [5,5] undecane (in the formula (1), m and n are 1, R ¹ and R ² are methyl compounds) 3,9-bis (2,4-dimethylphenyl) -2 ,
4,8,10-tetraoxaspiro [5,5] undecane (in the above formula (1), m and n are 2, R ¹ and R ² are methyl compounds) 3,9-bis (4-iso-butyl) Phenyl) -2,
4,8,10-tetraoxaspiro [5,5] undecane (in the above formula (1), m and n are 1, R ¹ and R ² are iso-butyl compounds) 3,9-bis (4-phenyl) Phenyl) -2,4,
8,10-tetraoxaspiro [5,5] undecane (in the above formula (1), m and n are 1, R ¹ and R ² are phenyl compounds)

Examples 1 to 5 Bisphenol A type polycarbonate resin (Panlite L-manufactured by Teijin Chemicals Ltd.)
1225) To 100 parts of the various acetal compounds shown in Table 1 were added in the amounts shown in Table 1 and melt-extruded at a barrel temperature of 260 to 280 ° C. using a φ30 mm uniaxial vent type extruder to obtain pellets. The pellets were dried in a hot air drier at 120 ° C. for 5 hours or more, and then injection molded at a cylinder temperature of 280 to 300 ° C. to produce a 2 mm thick transparent test piece. Using this test piece, cobalt 60γ ray was irradiated with 25 kilogray (kGy). During the deoxidation, irradiation was performed on the transparent test piece sealed in a bag with a commercially available deoxidizer. Yellowness before and after irradiation (ΔY
I) was measured according to JIS K7103. The results are shown in Table 1.

Reference Example 1 A transparent test piece of a polycarbonate resin was prepared in the same manner as in Example 1 except that no acetal compound was used, and the yellowing degree (ΔYI) before and after γ-ray irradiation was prepared using this test piece. I asked. The results are shown in Table 1.

[0046]

[Table 1]

[0047]

Industrial Applicability The polycarbonate resin composition of the present invention has little deterioration in physical properties and little change in color tone due to ionizing radiation irradiated for sterilization. Therefore, it is extremely useful for applications such as medical products to be subjected to ionizing radiation treatment and members of medical devices.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kunio Hatanaka 1-2-2 Uchisaiwaicho, Chiyoda-ku, Tokyo F-term in Teijin Chemicals Limited (reference) 4C081 AC01 AC06 AC08 AC09 AC11 AC15 BB03 CA201 CC01 DA03 4J002 CG011 CG021 CG031 EL126 FD036 GB01

Claims (3)

[Claims] 1. 100 parts by weight of a polycarbonate resin and 0.001 of an acetal compound represented by the following formula (1):
An ionizing radiation-stabilized polycarbonate resin composition comprising up to 20 parts by weight. Embedded image (In the formula, m and n are integers of 0 to 5, R ¹ and R ² may be the same or different, and each may be a hydrocarbon group having 1 to 18 carbon atoms, a hydrocarbon group having 1 to 18 carbon atoms. It represents at least one group selected from the group consisting of an oxy group, an acyl group having 1 to 18 carbon atoms, an acyloxy group having 1 to 18 carbon atoms, and a polyoxyhydrocarbon group having 2 to 8 carbon atoms.) 2. An acetal compound represented by the formula (1) is added in an amount of 0.1 to 100 parts by weight of a polycarbonate resin.
The ionizing radiation-stabilized polycarbonate resin composition according to claim 1, wherein the amount is from 01 to 5 parts by weight. 3. 100 parts by weight of a polycarbonate resin and 0.001 of an acetal compound represented by the formula (1).
A polycarbonate resin composition for a member of a medical device, comprising up to 20 parts by weight.