KR950000989B1 - Polyvinyl chloride compositions for medical use - Google Patents

Abstract

The medical soft vinyl chloride resin compsn. is composed of 100 wt.pts. of a vinyl chloride resin (A), 20-120 wt.pts. of a plasticizer (B) and 0.005-5 wt.pts. of a stilbene oxide. The vinyl chloride resin (A) is pref. vinyl chloride resin/vinyl acetate copolymer, acrylonitrile-butadiene-styrene (ABS), methyl methacrylate (MMA) or MBS. The plasticizer (B) is pref. phthalic acid ester, adipic acid ester or citric acid ester of dioctyl phthalate (DOP). The soft vinyl chloride resin has a good radioactive ray resistance.

Description

Medical vinyl chloride resin composition

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medical vinyl chloride resin composition, and more particularly, to a medical vinyl chloride resin composition which has excellent resistance to radiation and prevents the plasticizer from being transferred.

Conventionally, as a method for sterilizing medical vinyl chloride resin (PVC), a high pressure steam method, an ethylene oxide sterilization method, a radiation sterilization method and the like are known, of which radiation sterilization is most widely used. However, the radiation sterilization method is simpler and more reliable than other sterilization methods, but when the high energy such as γ-rays is irradiated onto the polymer material, the polymer main chain is changed, thereby degrading the value of the medical polymer material.

In particular, in the case of PVC, due to the characteristics of the PVC structure itself, when irradiated for the purpose of sterilization various degradation reactions occur as follows. In other words, chlorine molecules are dissociated by high energy to cause dechlorination (HCI) reaction on the PVC backbone, which increases the acid value as a medical material and causes factors that can irritate patients, and polyene is formed on the PVC backbone. It will yellow the PVC material.

In addition, the crosslinking reaction deteriorates the intrinsic properties of the polymer material, and if various oxidation reactions are carried out by oxygen remaining in the air, aldehyde groups, ketone groups, alcohol groups, etc. are eventually formed in the PVC main chain, and eventually the PVC main chain is decomposed. Is cut.

These degradation products cause odors and, more importantly, reduce the compatibility between the additives in the PVC product and promote the plasticizer implementation. Therefore, various methods for increasing the resistance to the γ-rays have been used, which is a method of adding and combining an antioxidant or an aromatic compound for absorbing the filtered radiation energy, an epoxy compound for trapping the generated radicals, and the like, There is a method of structurally replacing the PVC main chain with another monomer.

For example, the first is a method of formulating a secondary plasticizer, epoxidized soybean oil, more than conventional methods, that is, 20 to 25 parts by weight (A. Sexena et al., J. of Appl. Polym. Sci. , 34, 1727 (1987). However, this method is difficult to put to practical use because it drops a lot of physical properties of the medical PVC itself.

The second method is to replace the PVC part with polyethylene, which is resistant to γ rays, as a medical material. This method cannot be used for fluid tubes and blood tubes where polyethylene properties require physical properties such as transparency and flexibility such as PVC.

The third method is to replace the stabilizer of the organic stone system as a synergistic stabilizer to give γ-line resistance to Ca / Zn non-toxic stabilizer (JP 55-125144). However, this method has been used in a limited way for packaging because of the toxicity of the decomposition products of the organic stone system decomposed by the gamma ray.

In a fourth method, polyethylene glycol-400 is known to have excellent γ-resistance to polyols (G. Williams et al., J. Polym. Sci., Polym. Chem., 21 1491 (1983)). Because of its dissolution, that is, its water extractability is weak and is rarely used as a medical device.

Fifthly, it is a method of compounding and preserving inorganic antioxidants such as magnesium oxide, calcium oxide, zinc oxide and titanium oxide (FR 2,542,320), which has some effects on the prevention of yellowing but increases the transition of plasticizer after γ-ray irradiation. There is a problem that the color and transparency of the PVC itself is turbid by the disadvantages and these additives.

Sixth, commercially available UV absorbers, antioxidants (eg IRGANOX 1010) and amine antioxidants (eg TINUBIN 662, etc.) are used. There is a glyph in it, so it is not practical.

The seventh method is not a method of addition, but a method of substituting a chlorine group in the PVC molecular chain with a monomer having excellent gamma-ray resistance, that is, a monomer such as styrene or vinyl acetate. This method is somewhat resistant to radiation, but the disadvantage is that the process is expensive.

Therefore, at present, no method has been developed that can effectively improve the γ-ray ray of PVC.

On the other hand, such polymer materials include plasticizers, and typical plasticizers include diehexyl phthalate (DEHP). However, when the soft PVC plasticized with DEHP is used as a medical polymer material, such as a blood bag or a sap container, the plasticizer in the plasticized soft PVC is eluted with blood or sap to contaminate blood or contents. Of course, there is a problem that promotes denaturation of the contents, and also decreases the biosynthesis by greatly losing or changing the physical properties of the plasticized soft PVC itself.

Therefore, various methods have been tried to solve these problems.

The first method is to develop a formulation for minimizing the dissolution of DEHP, which is to find the best compatibility of additives by adjusting the appropriate amount of additives such as PVC, DEHP and stabilizers. This method requires an empirical method, which limits the amount of elution and requires a lot of manpower and time.

In the second method, a compatibilizer, which is a substance that prevents the dissolution of DEHP, is added to improve compatibility between the resin and the additive, and an appropriate amount of silane derivatives, which are mainly blood compatible materials, is blended ( JP 59-08744, JP 58-194492, JP 58-22222. However, this method is expensive and requires attention because the compounds in these silanes interact with the blood and sometimes clump the blood.

The third method is to change the plasticizer into a plasticizer that is not harmful to the human body or a plasticizer that is difficult to dissolve. For example, a tribasic monohydroxy acid derivative derived from natural products is used as a plasticizer ( Plastic Eng. June 1986. p28). In addition, as the plasticizer that is difficult to dissolve, trioctyltrimellitate (TOTM) and polymer plasticizers can be used, but since the plasticizer dissolution rate is obviously lower than that of DEHP, the plasticizer dissolution rate is obvious. There is a disadvantage in that a high cost is required to represent the plasticization rate (JP 58-211449, USP 4,478,961).

The fourth method is to create a layer that prevents the dissolution of the plasticizer on the inner surface in contact with blood by using ultraviolet rays, radiation, and plasma, and has a special gas (eg, CO, N) with a thickness of about 1 μm on the soft PVC surface. ₂ , Ar) using a special reaction to crosslink, this method is one of the most obvious method for increasing the non-compliance, but it is difficult to manufacture a device, expensive and difficult to manufacture a continuous device have.

The fifth method is laminating polyolefins and other films other than PVC on the inner surface in contact with blood. That is, a thin film such as polyethylene, polypropylene (BE 893,087), polyethylene terephthalate (BE 894,718), ethylene-vinylacetate copolymer (JP 60-236749), polyurethane (JP 60-236751), etc. Is laminated molding. In this method, complete adhesion is impossible during processing, and the coating layer is separated during long-term use, and lowers below Tg during low-temperature use, which may cause breakage.

The sixth method is to blend a resin that gives flexibility to PVC, and to blend EVA, NBR, SBR, and polyurethane, which give flexibility instead of low molecular weight plasticizer (DEHP) and polymer plasticizer (TOTM). .

However, such a method also has a limitation in use, and in particular, kneading with polyurethane or the like has a problem in that the method of removing unreacted residual isocyanate remaining in the polyurethane synthesis has been severely restricted in use.

As a seventh method, a copolymer of a flexible monomer and a vinyl chloride monomer or a graft polymerization of a vinyl chloride monomer to a flexible resin are known as internal plasticized PVC. The disadvantage of these is that the degree of plasticization must be controlled by the polymerization process and there is a difficulty in removing odor due to acetic acid, which is a decomposed product of vinyl acetate, which is internally plasticized during processing (JP 58-37019, JP 58-40312).

Therefore, looking at these conventional methods, there is virtually no method that can prevent the plasticizer inexpensively and completely in the medical plasticized soft PVC.

In the present invention, by using a stilbene oxide as a new additive will solve the problems of the prior art at the same time.

It is an object of the present invention to provide a novel medical vinyl chloride resin composition which is significantly improved in resistance to radiation while effectively preventing the performance of plasticizers.

Hereinafter, the present invention will be described in detail.

The present invention is a flexible vinyl chloride-based resin composition containing 20 to 120 parts by weight of plasticizer and 0.005 to 5 parts by weight of stilbene oxide with respect to 100 parts by weight of vinyl chloride resin.

The soft vinyl chloride-based resin composition according to the present invention is very suitable as a medical polymer material due to its excellent resistance to radiation while greatly reducing the dissolution of the plasticizer.

Referring to the present invention in more detail as follows.

In the soft vinyl chloride-based resin composition according to the present invention, a PVC resin may be a mixed resin such as ABS, MBS, MMA resin mainly composed of salt vinyl resin, vinyl chloride resin, vinyl acetate copolymer, and vinyl chloride resin. .

Moreover, as a plasticizer, the plasticizer used for plasticizing vinyl chloride-type resins, such as phthalic acid ester, adipic acid ester, citric acid ester, and epoxidized soybean oil which are normally used, can be used. The addition amount of this plasticizer can use 20-120 weight part with respect to 100 weight part of vinyl chloride resins.

PVC resin composition according to the present invention as described above, the amount of plasticizer which is the object of the present invention is reduced to about 1/2 to 1/10, even if the transparency and coloration are not comparable to that of ordinary PVC products. In addition, even when irradiated with γ-ray, the chromaticity was little changed.

This is because the two aromatic rings in the stilbene oxide molecule absorb the absorption of γ-ray, which is a high energy, and also remove the radicals generated in the PVC backbone with highly reactive oxirane groups and complex with the PVC backbone. have.

The addition amount of stilbenoxide can be used in 0.005-5 weight part with respect to 100 weight part of PVC. Here, excessive use of stilbene oxide is not good because the remaining stilbene oxide participating in the stabilizing effect promotes discoloration of the PVC compound, and when used in a small amount, there is an insufficient problem of stabilizing effect.

As described above, the PVC resin composition of the present invention not only prevents plasticizer migration but also has excellent γ resistance, so that various medical devices such as blood bags, blood sets, infusion sets, artificial kidney blood circuits, artificial cardiopulmonary blood circuits, As a sheet to a film, a connector and the like, as well as a food packaging container can be used in various ways.

Hereinafter, examples of the present invention will be described.

[Examples 1-3 and Comparative Examples 1-2]

In the composition ratio shown in Table 1 below, PVC and various additives were sufficiently mixed in a dry mixer at 120 ° C. for 40 minutes and melt mixed for 3 minutes in an open roll mixer, and then heated and pressurized at 170 ° C. for 5 minutes. To form a 0.3 mm thick film. The film was irradiated with γ-rays on the ⁶⁰ Co line, that is, 1.5 Mrads, 2.5 Mrads and 4 Mrads, to analyze the amount of plasticizer eluted in distilled water by using an ultraviolet absorption spectrometer. It was.

TABLE 1

Compounding amount

* IRGNOX 1010: tetrakis [methyl-3, (3,5-di-tert-redtyl-4-hydroxyphenyl) propionate] methane; Shiva-Geigy Company Antioxidant

TABLE 2

Changes in ecliptic (yellow index, YI) after irradiation

TABLE 3

Eluate after irradiation (220 nm)

PVC added stilbeneoxide according to the present invention has little change in chromaticity when irradiated for the purpose of sterilization as compared to the film without the addition, or the film added with antioxidants such as IRGANOX 1010.

[Examples 4 to 6 and Comparative Examples 3 to 4]

PVC and various additives were mixed as shown in Table 4, mixed well in an open roll mixer for 3 minutes, and a sheet of 0.5 mm thickness was formed as a press. Subsequently, the amount of plasticizer eluted in distilled water was analyzed by an ultraviolet absorption spectrometer to measure the amount of elution of DOP, and the results are shown in Table 5.

TABLE 4

* MDS: 3-chloropropylmethyldimethoxysilane

TABLE 5

According to the results of Table 5, the PVC added with an appropriate amount of stilbene oxide does not add the sheet, and the appearance and properties are not inferior to the polymer material to which the silane-based compound is added. It is reduced to -1/10.

PVC-based resin products according to the present invention is excellent in resistance to radiation without losing appearance processability, appearance, etc., and can be usefully used in the medical field, food field, and other fields by preventing the dissolution of plasticizers.

Claims (1)

A medical vinyl chloride resin composition comprising vinyl chloride resin and a plasticizer, and having a gamma-ray resistance, comprising 20 to 120 parts by weight of plasticizer and 0.005 to 5 parts by weight of stilbene oxide based on 100 parts by weight of vinyl chloride resin. Medical vinyl chloride resin composition.