CS253727B2 - Polyvinyl chloride based plastic for long-term contact with blood - Google Patents

Abstract

The solution relates to a polyvinyl chloride-based plastic for medical use for long-term contact with blood containing suspension polyvinyl chloride, di-2-ethylhexyl phthalate, epoxidized soybean oil, stabilizers from the group of calcium zinc salts of aliphatic acids, a lubricant and an antioxidant. The plastic contains as an antioxidant a compound from the group of trialkylphenols of the general formula c6h2ohr1r2r3, where R, means methyl or a tertiary group -C4H9, R2 means methyl and R3 means a tertiary group -C^Hg, in an amount of 0.05 to 0.15% by weight, based on the total weight of the plastic. The plastic has a reduced migration index for compounds with small molecules in an aqueous extract and at the same time allows for rapid and complete desorption of water vapor after steam sterilization.

Description

The invention relates to a polyvinyl chloride-based plastic for medical use for long-term contact with blood.

The main requirement for plastics for medical use that come into prolonged contact with blood is to reduce the possibility of extracting small organic molecules into the blood. The extent of this extraction is determined by the migration index, i.e. the oxidizability and absorption of organic compounds in the aqueous extract of the plastic.

Plastics for medical use are known which consist of polyvinyl chloride polymerized in suspension, using di-2-ethylhexyl phthalate and epoxidized soybean oil as plasticizers and, for example, calcium and zinc salts with stearic or lauric acid as stabilizers.

In the above-mentioned plastics, a certain decrease in the migration index for small molecules of organic compounds is achieved during leaching with water, processes in which various stabilizers are used.

According to one of these methods, migration reduction can be achieved by using silicone oil in the production of the plastic in an amount of 0.2 to 7 parts by weight, this oil being added in the form of an emulsion together with the plasticizer during the preparation of the dry mixture. Another known method for reducing migration is a method in which a crosslinked layer of 0.3 to 1 μm thick is formed on the surface of the plastic or on the surface of a product made of polyvinyl chloride materials, which forms a barrier to the migration of small molecule compounds from the inner layers of the plastic. This layer is usually formed in the case of polyvinyl chloride-based plastics by the action of radiation, for example ultraviolet light in air or in a nitrogen atmosphere.

A disadvantage of both of the above methods is the difficulty in achieving a significant reduction in the migration index for small molecule compounds while maintaining the possibility of rapid and complete desorption of water vapor from the plastic after steam sterilization. However, this also limits the use of the above plastics for manufacturing medical products that are to be steam sterilized, such as blood collection containers and blood preservation containers.

The subject of the invention is a polyvinyl chloride-based plastic for medical use for long-term contact with blood containing suspension polyvinyl chloride, di-2-ethylhexyl phthalate, epoxidized soybean oil, stabilizers from the group of calcium-zinc salts of aliphatic acids, a lubricant and an antioxidant, characterized in that as an antioxidant it contains a compound from the group of trialkylphenols of the general formula ^C 6 ^H 2 ^OIlR l ^R 2 ^R 3 where is methyl or a tertiary group -C^Hg,

R2 is methyl and

R ₃ represents a tertiary group -C 1 H 8 , in an amount of 0.05 to 0.15% by weight, based on the total weight of the plastic.

The plastic material according to the invention is characterized by a low migration index for small molecule compounds when leached with water and therefore meets the health requirements for materials that come into long-term contact with blood.

The plastic material according to the invention enables rapid and complete desorption of water vapor and thus meets the long-standing need for materials that are capable of being sterilized by water vapor.

The plastic according to the invention can be used to manufacture medical devices or parts thereof by known methods for processing plastics, i.e. extrusion, casting, pressing, calendering and rolling.

The properties of the plastic material according to the invention allow its use for the production of devices that come into long-term contact with blood and which are sterilized by steam, in particular for the production of blood collection containers and blood cans.

The invention will be illustrated by the following examples:

Example 1

A mixture is prepared consisting of 100 parts by weight of polyvinyl chloride suspension with a K number of 68, 47 parts by weight of di-2-ethylhexyl phthalate, 2 parts by weight of epoxidized soybean oil, 0.15 parts by weight of 2,2-dimethyl-6-tert-butylphenol, 0.1 part by weight of lubricating grease, 1.5 parts by weight of calcium-zinc salt of stearic acid and this mixture is homogenized for 20 minutes in a mixing device at a temperature of 120 °C. Granulate is extruded from the dry mixture thus obtained at a temperature of 160 to 180 °C. The granulate obtained in this way can be further processed by all methods for conventional processing of plastics.

Example 2

A mixture of 100 parts by weight of polyvinyl chloride suspension with a K number of 68, 36 parts by weight of di-2-ethylhexyl phthalate, 2 parts by weight of epoxidized soybean oil, 0.10 parts by weight of 4-methyl-2,6-di-tert.butylphenol, 0.1 part by weight of lubricating grease, 1.5 parts by weight of calcium zinc salt of stearic acid is prepared and the mixture is homogenized for 20 minutes with a mixing device at a temperature of 120 °C. The dry mixture thus obtained is extruded at a temperature of 160 to 180 °C into granules, which can be further processed by any method for processing plastics.

The following Table 1 shows a comparison of the properties of known plastics with the properties of the plastic according to the invention.

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Claims (1)

SUBJECT OF THE INVENTION Polyvinyl chloride-based plastic for medical use for long-term contact with blood containing suspension polyvinyl chloride, di-2-ethylhexyl phthalate, epoxidized soybean oil, calcium zinc salt stabilizers, lubricating agent and anti-oxidizing agent, characterized as an anoxidizing agent it contains a compound from the group of trialkylphenols of the general formula C _c H _n OHR ₁ R-R-