JPH0436343A - Ionizing radiation-resistant polycarbonate resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can remarkably prevent yellowing caused by irradiation with an ionizing radiation and can resist aging without detriment to the properties inherent in a polycarbonate resin by mixing a polycarbonate resin with a certain sulfur compound and optionally a phosphorus antioxidant. CONSTITUTION:This composition comprises 100 pts.wt. polycarbonate resin, 0.01-3 pts.wt. ethylene glycol dithioglycolate and/or methyl thioglycolate and optionally 0.001-1 pt.wt. phosphorus antioxidant. Examples of the phosphorus antioxidants include trialkyl phosphites, tricylcloalkyl phosphites, triaryl phosphites, alkyl diaryl phosphites and diphosphites, among which tris(2,4-di-tert.- butylphenyl) phosphite is particularly desirable.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a novel polycarbonate resin composition resistant to ionizing radiation, and more specifically, a novel polycarbonate resin composition that is resistant to ionizing radiation. The present invention relates to a polycarbonate resin composition resistant to ionizing radiation, which has characteristics such as no yellowing, very little yellowing, and little change over time, and is suitable for use as a material for various medical instruments, for example.

[Prior art] Polycarbonate resin has excellent toughness, impact resistance, heat resistance, dimensional stability, transparency, etc., so it is widely used as a thermoplastic engineering plastic in various fields, and one of its uses is , various medical instruments,
For example, they are used in containers for syringes, surgical instruments, blood transfusion sets, etc., as well as in artificial lungs, artificial kidneys, anesthesia inhalation devices, intravenous connectors, and accessories.

Such medical instruments are sterilized before use. Conventionally, a method using ethylene oxide gas or a steam sterilization method in an autoclave has been used for this sterilization treatment, but in recent years, methods using ionizing radiation such as gamma rays are being adopted.

However, polycarbonate resin is unstable to ionizing radiation such as gamma rays, and when irradiated with ionizing radiation for sterilization, it has drawbacks such as yellowing and, in severe cases, a decrease in mechanical strength. There is. Therefore, in order to improve these drawbacks, attempts have been made to incorporate gastric coloring agents to offset the yellowing, and to incorporate certain additives (Japanese Patent Application Laid-Open No. 192759-1982). No. Publication,
JP-A-61-215651, JP-A-62-135
No. 556, Japanese Unexamined Patent Publication No. 63-314269), none of these methods can necessarily be said to be sufficient in preventing yellowing.

Furthermore, it has been proposed to blend an ester having a mercapto group obtained from thioglycolic acid or mercaptopropionic acid and alcohol into a polycarbonate resin (Japanese Unexamined Patent Publication No. 249058); Compounds do not exhibit sufficient anti-yellowing effects and are not necessarily satisfactory.

[Problems to be Solved by the Invention] Under these circumstances, the present invention provides a polycarbonate resin that does not lose its original excellent properties even when irradiated with ionizing radiation, and has extremely little yellowing. This invention was made with the aim of providing a polycarbonate resin composition resistant to ionizing radiation, which has characteristics such as small change over time and is suitable for use as a material for various medical instruments, for example.

[Means for Solving the Problem] As a result of intensive research to develop a polycarbonate resin composition resistant to ionizing radiation having the above-mentioned preferable properties, the present inventor has added certain sulfur compounds and, in some cases, phosphorus to the polycarbonate resin. It was discovered that the objective could be achieved by blending antioxidants in a specific proportion, and based on this knowledge, the present invention was completed.

That is, the present invention provides (A) polycarbonate resin 10
(B) ethylene glycol dithioglycolate and/or methyl thioglycolate 0.01 to 0 parts by weight
3 parts by weight and optionally (C) 0.0 phosphorus antioxidant
The present invention provides an ionizing radiation-resistant polycarbonate resin composition containing 1 to 1 part by weight of 0.01 to 1 part by weight.

The present invention will be explained in detail below.

In the composition of the present invention, the polycarbonate resin used as component (A) has the following formula:
8 alkylene group, C2-8 alkylidene group, C5-15 cycloalkylene group, C5-15 cycloalkylidene group, simple bond, -5Oz--5O
-s--o--co- or CH, CH.

R1 and R2 are each a hydrogen atom, a chlorine atom, a bromine atom, or an alkyl group having 1 to 8 carbon atoms, and they may be the same or different, and m and n are
Each is an integer from 1 to 4, and if m is 2 to 4, R
1 may be different from I, and n is 2 to
In the case of R2, R2 may be different from each other).

The polycarbonate resin can be prepared by reacting a dihydric phenol with a carbonate precursor such as phosgene or by reacting a dihydric phenol with a carbonate precursor such as phosgene in a solvent such as methylene chloride in the presence of a known acid acceptor or molecular weight modifier. It can be produced by a transesterification reaction with a carbonate precursor such as.

As the dihydric phenol, for example, 2,2-bis(4
-Hydroxyphenyl)propane (bisphenol A)
, 2.2-bis(3-methyl-4-hydroxyphenyl)propane, 2.2-bis(3,5-'; methyl-4-
hydroxyphenyl)propane, 1.2-bis(4-hydroxyphenyl)ethane, 3.3-bis(4-hydroxyphenyl)pentane, 1.1-(4-hydroxyphenyl)cyclohexane, 4.4'-dihydroxydiphenyl , bis(4-hydroxyphenyl) sulfide,
Bis(4-hydroxyphenyl)sulfone, bis(4-
hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl) ether, 4,4′-dihydroxybenzophenone, etc., or 2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane, 2,2-bis(3 , 5-cyclo4-hydroxyphenyl)propane, 2.2-bis(3-chloro-4-hydroxyphenyl)propane, 2.2-bis(3-promo4-hydroxyphenyl)propane. Among these dihydric phenols, bisphenol A is particularly suitable.

Further, these dihydric phenols may be used alone or in combination of two or more types. Furthermore, the polycarbonate resin used in the present invention may be a thermoplastic random branched polycarbonate made by reacting a polyfunctional aromatic compound with a dihydric phenol and/or a carbonate precursor, or a polycarbonate resin made of two or more types of polycarbonate resins. It may also be a blend of.

The polycarbonate resin has a viscosity average molecular weight of 10.000 to 100.0 from the viewpoint of mechanical strength and moldability.
00 is preferable, especially 20,000 to 40,0
00 is preferred.

In the composition of the present invention, it is necessary to incorporate ethylene glycol dithioglycolate and/or methyl thioglycolate as component (B). Its blending amount is
The amount is selected in the range of 0.01 to 3 parts by weight, preferably 0.05 to 2 parts by weight, based on 100 parts by weight of the polycarbonate resin of the component (A). If this amount is less than 0.01 part by weight, the effect of the present invention will not be fully exhibited, and if it exceeds 3 parts by weight, there is a tendency for tensile strength, retention thermal stability, steam resistance, etc. after irradiation with ionizing radiation to decrease. It will be done.

In the composition of the present invention, in order to better exhibit the effects of the present invention, in some cases, together with the component (B),
A phosphorus antioxidant may be added as component (C).

Examples of the phosphorus antioxidant include trimethyl phosphite, triethyl phosphite, tributyl phosphite, trioctyl phosphite, trinonyl phosphite, tridecyl phosphite, triotadecyl phosphite, and tris(2-chloroethyl) phosphite. phyto, trialkyl phosphites such as tris(2,3-dichloropropyl) phosphite, tricycloalkyl phosphites such as tricyclohexyl phosphite, triphenyl phosphite, tricresyl phosphite, tris(ethylphenyl) Phosphite, Tris (
butylphenyl) phosphite, tris(2,4-di-
t-butylphenyl) phosphite, tris(nonylphenyl) phosphite, tris(hydroxyphenyl)
phosphite, triarylphosphites such as cresyl diphenyl phosphite, 2-ethylhexyl diphenyl phosphite, decyl diphenyl phosphite,
Alkyl diarylphosphites such as tridecyl diphenyl phosphite, distearyl pentaerythrityl diphosphite, bis(2,4-di-t-butylphenylto, bis(2,6-di-t-butyl-4-methyl) phenyl) pentaerythrityl diphosphite, tetrakis(
Examples include diphosphites such as 2.4-di-t-butylphenyl)-4,4'-biphenylene diphosphite and tetraphenyldipropylene glycol diphosphite, among which tris(2,4 -G-t-
Butylphenyl) phosphite is particularly preferred.

These phosphorus-based antioxidants may be used alone or in combination of two or more, and the blending amount is from 0.001 to 100 parts by weight of the polycarbonate resin as component (A). 1 part by weight, preferably o, oos
-0.5 parts by weight. This amount is 0.001
If the amount is less than 1 part by weight, the effect of addition will not be sufficiently exhibited, and if it exceeds 1 part by weight, no improvement in the effect will be observed in relation to the amount, but rather a tendency for steam resistance to decrease.

The composition of the present invention may optionally contain other additives conventionally used in polycarbonate resin compositions, such as hindered phenolic antioxidants, salicylates, benzophenone, It may contain ultraviolet absorbers such as triazole type, hindered amine type light stabilizers, flame retardants, coloring agents, mold release agents, etc.

There are no particular restrictions on the method for preparing the composition of the present invention, and methods conventionally used for preparing thermoplastic resin compositions may be used, such as the method for preparing the above-mentioned (A) component, (B) component, and optionally used (C) component. The required amounts for each of the various additive ingredients, ■-
Blender Lipon blender, Henschel mixer,
Mix in a tumbler or after mixing,
Furthermore, a method of melting and kneading using a Banbury mixer, kneader, open roll, single screw extruder, twin screw extruder, single screw reciprocating screw kneader, etc. can be used. In this case, the melt-kneading temperature is usually selected within the range of 250 to 300°C.

The composition of the present invention thus obtained can be molded into a desired molded article by a molding method such as injection molding, extrusion molding, or compression molding.

[Example] Next, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

In addition, each physical property was calculated|required by the following method.

(1) Yellowness index (YI) Measured using Colormeter 5M-3 manufactured by Suga Test Instruments Co., Ltd. in accordance with JIS K-7103.

(2) Tensile strength It was determined in accordance with ASTM D-638.

(3) M steam In an autoclave, the test piece was heated to 121°C for 2 hours.
After being exposed for 4 hours, steam resistance was evaluated based on visual judgment of appearance and tensile strength.

Judgment criteria for appearance O: Very good O: Good Δ: Fairly bad ×: Bad (4) Retention thermal stability Using a capillary rheometer, pellets were
After staying in the cylinder at ℃ for 20 minutes, the strand was extruded and its appearance was visually evaluated according to the following criteria.

O: Good Δ: Not sufficient ×: Bad Example 1 Polycarbonate resin dried in a hot air dryer at 120°C for 15 hours [manufactured by Idemitsu Petrochemical Co., Ltd., Ri70/FN220]
0, average molecular weight 21,500] 100 parts by weight and 0.05 parts of ethylene glycol dithioglycolate! and 0.02 parts by weight of tris(2,4-di-t-butylphenyl) phosphite (manufactured by Ciba Gaiki Co., Ltd., Irgafuos 16 g) were mixed mechanically, and a mixture of
After extrusion at 70° C., the strands were cooled with water, and then cut with a pelletizer to obtain pellets. Next, the pellets were molded with a vent molding machine at 270° C. to prepare predetermined test pieces.

This test piece was given 2.5Mr at the Japan Isotope Association.
Ad gamma rays were irradiated, and the yellowness (Yl) and tensile strength were measured on the second day after irradiation. The yellowness was also measured after 20 days to evaluate changes over time.

Furthermore, in order to examine its suitability as a molding material, steam resistance and retention heat stability were evaluated. The results are shown in Table 1.

5I! Journey Examples 2 to 4 Example 1 except that the amount of ethylene glycol dithioglycolate was changed as shown in Table 1.
It was carried out in the same manner. The results are shown in Table 1.

Examples 5 to 8 Examples were carried out in the same manner as in Example 1, except that methyl thioglycolate in the amount shown in Table 1 was used instead of ethylene glycol dithioglycolate as a modifier. The results are shown in Table 1.

Examples 9 to 12 Examples 9 to 12 were carried out in the same manner as in Example 1, except that ethylene glycol dithioglycolate and methyl thioglycolate in the amounts shown in Table 1 were used in combination as modifiers.

The results are shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that ethylene glycol dithioglycolate was not used. The results are shown in Table 2. As can be seen from Table 2, the yellowness after γ-ray irradiation is extremely high.

Comparative Examples 2 to 9 In Example 4, 1 of the compounds shown in Table 2 was used instead of ethylene glycol dithioglycolate as a modifier.
．． The same procedure as in Example 4 was carried out except that 0 part by weight was used. The results are shown in Table Wg2.

As can be seen from Table 2, in Comparative Examples 2 to 5, the yellowness after γ-ray irradiation was large, and no improvement effect was observed. In addition, Comparative Example 6.7 has an improvement effect on yellowness, but has poor retention heat stability and is unsuitable as a molding material.Comparative Example 8.9 has a large change in Yl after irradiation with time and retains heat. Stability is also slightly lower.

Comparative Example 10 The same procedure as in Example 1 was carried out except that the amount of ethylene glycol dithioglycolate used was changed to 5 parts by weight. The results are shown in Table 2.

As can be seen from Table 2, although an improvement effect on the yellowness was observed, the steam resistance and retention heat stability were poor, making it unsuitable as a molding material.

Example 13.14 In Example 4, PE instead of Irgafuos 16B
P-36 [Manufactured by Adeka Argus Co., Ltd., trade name] 0.02
Parts by weight (Example 13), TNP [manufactured by Sumima Kagaku Co., Ltd. 10
．． The experiment was carried out in the same manner as in Example 4, except that 0.2 parts by weight (Example 14) was used.

The results are shown in Table 1.

As can be seen from Table 1, both Examples 13 and 14 are slightly inferior to Example 4 in steam resistance.

Note that PEP-36 is bis(2,6-sheet-t-butyl-4-methylphenyl)pentaerythrityl diphosphite, and TNP is tris(nonylphenyl)phosphite.

Comparative Example 11 In Example 4, the amount of Irgafuos 168 used was 1.
The same procedure as in Example 4 was carried out except that the amount was changed to 5 parts by weight. The results are shown in Table 2.

As can be seen from Table 2, it has poor steam resistance and is unsuitable as a molding material.

(The following is a blank space) [Effects of the invention] The ionizing radiation-resistant polycarbonate resin l:i paraboloid of the present invention has the inherent excellent properties of polycarbonate resin even when irradiated with ionizing radiation, and does not yellow. It has characteristics such as extremely low oxidation and small change over time, and is suitable for use as a material for various medical instruments, for example.

Claims (1)

[Claims] 1(A) For 100 parts by weight of polycarbonate resin, (
B) An ionizing radiation-resistant polycarbonate resin composition containing 0.01 to 3 parts by weight of ethylene glycol dithioglycolate and/or methyl thioglycolate. 2(A) For 100 parts by weight of polycarbonate resin, (
B) 0.01 to 3 parts by weight of ethylene glycol dithioglycolate and/or methyl thioglycolate; and (C)
An ionizing radiation-resistant polycarbonate resin composition containing 0.001 to 1 part by weight of a phosphorous antioxidant. 3. The ionizing radiation resistant polycarbonate resin composition according to claim 2, wherein the phosphorus antioxidant is tris(2,4-di-t-butylphenyl) phosphite.