JPH08319407A - Polycarbonate resin composition resistant to ionizing radiation and medical molding made thereof - Google Patents

Abstract

PURPOSE: To obtain a polycarbonate resin composition which scarcely undergoes a change in hue and the deterioration in properties when it is irradiated with an ionizing radiation for sterilization. CONSTITUTION: This composition comprises 100 pts.wt. polycarbonate resin and 0.01-5 pts.wt. aromatic hydrocarbon aldehyde resin having an oxygen content of 8wt.% or above and being excellent in resistance to an ionizing radiation and a medical molding made thereof is provided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polycarbonate resin composition having excellent resistance to ionizing radiation. More specifically, the present invention relates to a polycarbonate resin composition with little change in color tone and deterioration in physical properties due to ionizing radiation irradiated for sterilization.

[0002]

2. Description of the Related Art Polycarbonate resins have excellent mechanical strength, impact resistance, heat resistance, transparency and high safety, and are therefore widely used for molding medical products. A molded article for medical use is usually completely sterilized before use.
Specific examples include a high-pressure steam sterilization method, an ethylene oxide gas (EOG) sterilization method, and a sterilization method by irradiation with ionizing radiation such as gamma rays and electron beams. However, among these, the high-pressure steam sterilization method has problems that the energy cost is high and that a drying step is required after the sterilization treatment. In addition, the EOG sterilization has various problems such as toxicity of EOG itself and environmental problems related to disposal.

Therefore, recently, it is relatively inexpensive and has a low temperature.
Ionizing radiation (generally gamma radiation) irradiation sterilization methods, which can be processed dry, have become popular. However, when the polycarbonate resin is irradiated with ionizing radiation for sterilization, it usually turns yellow due to deterioration of the resin, and as a result of such yellowing, the product value is impaired particularly in medical applications. have.

As a method for solving such a drawback, for example, a method of blending a boron compound in Japanese Patent Publication No. 2-17582 and a method of blending a polyether polyol or its alkyl ether in Japanese Patent Publication No. 4-77025. However, Japanese Patent Application Laid-Open No. 1-229052 describes a method of adding thioalcohols, and Japanese Patent Application Laid-Open No. 2-0115260 describes a method of adding thioethers. However, even in these methods, the yellowing inhibitory effect is still insufficient, or if the addition amount is increased enough to obtain a sufficient effect, other physical properties are adversely affected, and a foul odor is generated during use. There is a problem such as doing.

Further, in Japanese Patent Publication No. 6-22586,
The method of blending halogen-containing polycarbonate resin,
Japanese Unexamined Patent Publication No. 5-179127 describes a method of blending a nuclear brominated phthalic acid derivative, but since halogen is contained in the composition, there is a possibility that metal corrosion may occur, so that it may be used in a molding machine or the like. There is a problem that it is necessary to use a metal of a special material.

[0006]

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a polycarbonate resin composition suitable for medical use, which has little change in color tone and deterioration of physical properties due to ionizing radiation irradiated for sterilization, and a molded article thereof. To do.

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventor has found that the polycarbonate resin is blended with an aromatic hydrocarbon aldehyde resin having an oxygen content of at least 8% by weight to improve ionizing radiation resistance. It was found that a polycarbonate resin composition having excellent properties, no bad odor, and no risk of metal corrosion can be obtained, and the present invention has been accomplished.

That is, according to the present invention, 100 parts by weight of a polycarbonate resin is mixed with 0.
01 to 5 parts by weight, and the aromatic hydrocarbon aldehyde resin has an oxygen content of at least 8% by weight.
The present invention relates to a polycarbonate resin composition having excellent resistance to ionizing radiation.

By the way, a composition in which an aromatic hydrocarbon aldehyde resin is blended with a polycarbonate resin is known in order to improve the flowability and the moldability of the polycarbonate resin (Japanese Patent Publication No. 52-783). However, as in the present invention, there is no description about the improvement of the ionizing radiation resistance of the polycarbonate resin by adding a small amount of the aromatic hydrocarbon aldehyde resin, and such a technical idea is suggested. There is nothing to do.

The polycarbonate resin used in the present invention is a thermoplastic aromatic aromatic hydrocarbon which may be obtained by reacting an aromatic dihydroxy compound or a small amount of this polyhydroxy compound with phosgene or a diester of carbonic acid. It is a polycarbonate polymer or copolymer. In the present invention, the molecular weight of the polycarbonate resin is, for example, in the case of a polycarbonate resin derived from bisphenol A, a viscosity average molecular weight converted from a methylene chloride solution viscosity at 25 ° C. of 1
0000 to 100,000, preferably 15,000 to 50
Those in the range of 000 are used.

Specific examples of the aromatic dihydroxy compound include 2,2-bis (4-hydroxyphenyl) propane (= bisphenol A) and 2,2-bis (3,5-dibromo-4-hydroxyphenyl) propane ( = Tetrabromobisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl)
Ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxyphenyl) octane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 1,1-bis (3-t-butyl-4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane, 2,2
-Bis (3-bromo-4-hydroxyphenyl) propane, 2,2-bis (3,5-dichloro-4-hydroxyphenyl) propane, 2,2-bis (3-phenyl-4)
-Hydroxyphenyl) propane, 2,2-bis (3-
Cyclohexyl-4-hydroxyphenyl) propane,
Bis (hydroxyaryl) alkanes exemplified by 1,1-bis (4-hydroxyphenyl-1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane, etc .; 1,1-bis (4-hydroxyphenyl) cyclopentane , 1,1-bis (4-hydroxyphenyl) cyclohexane and other bis (hydroxyaryl) cycloalkanes; 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, etc. Examples of dihydroxydiaryl ethers: 4,4′-dihydroxydiphenyl sulfide, 4,4′-dihydroxy-3,3′-
Dihydroxydiaryl sulfides exemplified by dimethyldiphenyl sulfide and the like; 4,4′-dihydroxydiphenyl sulfoxide, 4,4′-dihydroxy-
Dihydroxydiaryl sulfoxides exemplified by 3,3′-dimethyldiphenyl sulfoxide; 4,4 ′
-Dihydroxydiarylsulfones exemplified by dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone and the like; hydroquinone, resorcin, 4,4'-dihydroxydiphenyl and the like. You may use these aromatic dihydroxy compounds individually or in mixture of 2 or more types. Of these, 2,2-bis (4-hydroxyphenyl) propane is particularly preferably used.

Further, in order to obtain a branched aromatic polycarbonate resin, phloroglysin, 2,6-dimethyl-
2,4,6-tri (4-hydroxyphenyl) -3-heptene, 4,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) -2-heptene, 1,3,5-tri ( 2-hydroxyphenyl) benzol, 1,1,1-
Tri (4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5-methylbenzyl) -4-methylphenol, α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,3 Polyhydroxy compounds exemplified by 5-triisopropylbenzene and the like, 3,3-bis (4-hydroxyaryl) oxindole (= isatin bisphenol), 5-chloroisatin bisphenol, 5,7-dichloroisatin bisphenol , 5-
Bromisatin bisphenol and the like are used.

When the polycarbonate is produced by the phosgene method, a terminal stopper or a molecular weight modifier may be used. As the terminal terminator or the molecular weight modifier, a compound having a monovalent phenolic hydroxyl group or a compound having an aromatic carboxylic acid group can be used. Specifically, phenol, pt-butylphenol, tribromophenol, long-chain alkylphenol, aliphatic carboxylic acid chloride, aliphatic carboxylic acid, hydroxybenzoic acid alkyl ester, alkyl ether phenol,
Examples thereof include benzoic acid and alkylbenzoic acid.

In the present invention, these polycarbonate resins may be used alone or in combination of two or more.

The aromatic hydrocarbon aldehyde resin used in the present invention is a resin known per se and is a resin obtained by reacting an aromatic hydrocarbon with an aldehyde in the presence of an acid catalyst. Further, if necessary, it can be modified with at least one modifier selected from the group consisting of phenols, aromatic carboxylic acids, aliphatic or alicyclic carboxylic acids, alcohols, and amines. .

Specific examples of aromatic hydrocarbons include monocyclic aromatic hydrocarbon compounds such as benzene, toluene, ethylbenzene, xylene, methylethylbenzene, trimethylbenzene, tetramethylbenzene and cumene, and naphthalene, methylnaphthalene and ethyl. Examples thereof include polycyclic aromatic hydrocarbon compounds such as naphthalene, dimethylnaphthalene, acenaphthene, and anthracene. These aromatic hydrocarbons may be used alone or in combination of two or more. Of these, toluene, xylene, mesitylene, pseudocumene, naphthalene, etc. are particularly preferably used.

Specific examples of the aldehyde include saturated aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, valeraldehyde, laurinaldehyde and stearaldehyde; guloxal,
Aliphatic polyaldehydes such as succindialdehyde; unsaturated aliphatic aldehydes such as acrolein, crotonaldehyde, propiolaldehyde; benzaldehyde, tolualdehyde, salicylaldehyde, cinnamaldehyde, naphthaldehyde, etc. Aromatic aldehydes exemplified; heterocyclic aldehydes exemplified by furfural; aldehyde derivatives exemplified by methylal, dioxolane, trioxane, tetraoxane, paraformaldehyde, paraaldehyde, metaaldehyde and the like. These aldehydes may be used alone or in combination of two or more. Of these, formaldehyde, trioxane, paraformaldehyde and acetaldehyde are particularly preferably used.

As described above, an aromatic hydrocarbon aldehyde resin obtained by reacting an aromatic hydrocarbon with an aldehyde in the presence of an acid catalyst generally has various groups in which an aromatic ring is derived from an aldehyde. It is a mixture of various compounds bound together. For example, when formaldehyde is used as the aldehyde, the aromatic ring has a methylene group (—CH ₂
-), methylene ether groups (-CH ₂ OCH ₂ -), an acetal group _{(-CH 2 (OCH 2) n} OCH 2 -, where mixtures n is containing various compounds bound a positive integer) such as the group Is.

In the present invention, the aromatic hydrocarbon aldehyde resin has an oxygen content of at least 8 of these.
Weight%, preferably 10% or more is used. Oxygen in the aromatic hydrocarbon aldehyde resin is not only a polyvalent oxygen-containing group such as an alkylene ether group or an acetal group which is bonded to the aromatic ring as described above, but also an alkoxy group at the end (eg, -OCH ₃ ), A hydroxyalkyl group (eg, —CH ₂ OH), an acetal group (eg, —C)
It is provided by an aldehyde-derived monovalent oxygen-containing group having a group such as H ₂ (OCH ₂ ) n OCH ₃ ).

Such an aromatic hydrocarbon aldehyde resin can be easily obtained as a commercial product. Specifically, those offered by Mitsubishi Gas Chemical Co., Ltd. under the trade names Nikanol H, Nikanol L, Nikanol G, Nikanol Y, Nikanol M, and General Petrochemical Co., Ltd. under the trade names Generalite 6010 and Generalite 5100. The things that are done are listed.

However, by using such an aromatic hydrocarbon aldehyde resin, it becomes possible to obtain a polycarbonate resin composition having a small change in color tone due to ionizing radiation. That is, when the oxygen content is less than 8% by weight, the effect of suppressing yellowing upon sterilization by irradiation with ionizing radiation, which is the object of the present invention, cannot be sufficiently achieved.

In the present invention, these aromatic hydrocarbon aldehyde resins are used alone or in combination of two or more.

The amount of the aromatic hydrocarbon aldehyde resin used in the present invention is 0.01 to 5 parts by weight based on 100 parts by weight of the polycarbonate resin. Blending amount 0.01
If it is less than 5 parts by weight, the desired effect of improving the degree of yellowing due to irradiation with ionizing radiation is insufficient, while if it exceeds 5 parts by weight, mechanical properties, heat resistance, etc. are deteriorated, which is not preferable.
The preferable blending amount is 0.1 to 2 parts by weight in order to achieve a sufficient effect of suppressing yellowing due to irradiation with ionizing radiation, with little deterioration in mechanical properties, heat resistance and the like.

In the present invention, the method of blending the aromatic hydrocarbon aldehyde resin with the polycarbonate resin is as follows:
This can be done by various methods known to those skilled in the art.
For example, there is a method of mixing with a tumbler, a Henschel mixer, or the like, or a method of quantitatively supplying to an extruder hopper with a feeder and mixing.

The composition of the present invention further has the following objects.
Other additives that give desired properties may be added. Other additives include, for example, flame retardants, antioxidants, heat stabilizers, antistatic agents, plasticizers, release agents, lubricants, compatibilizers,
Examples include foaming agents, glass fibers, carbon fibers, reinforcing agents such as ceramic whiskers, fillers, dyes and pigments, and the like.
These additives may be added alone or in combination of two or more.

The composition of the present invention can be formed into a desired molded article by a conventional molding method such as injection molding or blow molding. Examples of medical molded articles for which it is desired to apply the ionizing radiation resistant polycarbonate resin composition of the present invention, specifically, artificial dialyzer, artificial lung, inhalation device for anesthesia, vein connector and accessories , Blood centrifuge bowls, surgical tools, operating room tools, tubes supplying oxygen to blood, tube connections, heart probes and syringes,
Examples thereof include surgical tools, operating room instruments, and containers for containing intravenous injections and the like.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0028]

EXAMPLES The raw materials used in each example are as follows. Polycarbonate resin: Iupilon S-2000 (manufactured by Mitsubishi Gas Chemical Co., Inc., poly-4,4'-isopropylidene diphenyl carbonate having a viscosity average molecular weight of 25,000.) Aromatic hydrocarbon aldehyde resin: See Table 1.

[0029]

[Table 1]

Examples 1 to 8 and Comparative Examples 1 and 2 100 parts by weight of a polycarbonate resin and an aromatic hydrocarbon aldehyde resin of the type and amount shown in Table 2 were mixed in a tumbler, and each 40 mmφ uniaxial vent. A pellet was obtained by extruding at a barrel temperature of 270 ° C. using a type extruder.

The pellets were heated in a hot air dryer at 120
After drying at 5 ° C. for 5 hours or more, injection molding was performed at a resin temperature of 270 ° C. and a mold temperature of 80 ° C. to prepare a 50 mmφ × 3 mm thick test piece. This test piece was irradiated with cobalt 60 γ rays at 25 kilogray (kGy), and the yellowness index (YI) before and after irradiation was measured according to JIS K 7103, a color difference meter (Suga Test Instruments Co., Ltd., trade name SM-3-CH). Was used to determine the difference in yellowness and the degree of yellowing (ΔYI).
Table 2 shows the results.

[0032]

[Table 2]

[0033]

INDUSTRIAL APPLICABILITY The composition of the present invention has little change in color tone due to ionizing radiation irradiated for sterilization, and can maintain a good appearance even after sterilization by irradiation with ionizing radiation. It is useful for applications.

Claims (5)

[Claims] 1. An aromatic hydrocarbon aldehyde resin of 0.01 to 5 parts by weight is mixed with 100 parts by weight of a polycarbonate resin, and the oxygen content of the aromatic hydrocarbon aldehyde resin is at least 8% by weight. An ionizing radiation resistant polycarbonate resin composition comprising: 2. Aromatic hydrocarbon aldehyde resin 0.1 to 2
The polycarbonate resin composition according to claim 1, wherein the polycarbonate resin composition is blended in parts by weight. 3. A polycarbonate resin composition according to claim 1, wherein the aromatic hydrocarbon aldehyde resin has an oxygen content of at least 10% by weight. 4. An aromatic hydrocarbon aldehyde resin is selected from the group consisting of formaldehyde, trioxane, paraformaldehyde and acetaldehyde and at least one aromatic hydrocarbon selected from the group consisting of toluene, xylene, mesitylene, pseudocumene and naphthalene. The polycarbonate resin composition according to claim 1, which is obtained by reacting at least one selected aldehyde in the presence of an acid catalyst. 5. A medical molded article comprising the polycarbonate resin composition according to any one of claims 1 to 4.