MXPA99008790A - Low modulus and autoclavable monolayer medical tubing - Google Patents

Abstract

A steam sterilizable monolayer medical tubing comprising a blend of a melt strength enhancing agent of a homopolymer or copolymer of polypropylene having a melt flow index of greater than 10 and in an amount of 1-10%by weight and a second component selected from the group of (i) a selectively hydrogenated block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene and (ii) a selectively hydrogenated block copolymer of a vinyl aromatic hydrocarbon and a conjugated diene to which has been grafted, an alpha, beta-olenfically unsaturated monocarboxylic or dicarboxylic acid reagent.

Description

MEDICAL PROBE OF A LOW AND AUTOCLAVABLE MODULE LAYER TECHNICAL FIELD This invention relates to medical probe compositions and more specifically to a one-layer probe that is autoclavable, lends itself to high-speed maquila and ligation to polymers such as polycarbonates, poly esters and polypropylenes.

Prior Technology In the medical field, where beneficial agents are collected, processed and stored in containers, transported and finally delivered through probes by infusion to the patient, there has been a recent trend towards the development of useful materials in the manufacture of such containers and probes without the disadvantage of the material currently used, such as polyvinyl chloride (PVC). These medical materials for probes should possess a unique combination of properties, so that the probe can be used in sets for the administration of liquids and with medical infusion pumps. These materials must have good ligation properties, sufficient strength to give themselves and flexibility, be environmentally friendly and compatible with medical solutions, exhibit poor quality of forming a spiral. Besides, to be commercially viable, the probe must be expelled at high speeds, at more than 50 feet / min. It is a requirement that the probe be environmentally compatible because a large amount of medical probe is disposed of in landfills and through incineration. For probes disposed of in sanitary landfills, it is desirable to use as little material as possible in their manufacture. For this purpose, it is desirable to use material that is thermoplastically recyclable so that the fragments left over from the maquila can be remanufactured into other useful articles. For the probe that is discarded by means of incineration, it is necessary to use a material that does not generate or that inhibits the formation of derivatives such as inorganic acids that can be harmful to the environment, irritating and corrosive. For example, polyvinyl chloride can generate inconvenient amounts of hydrogen chloride (or hydrochloric acid when in contact with water) when incinerated causing corrosion to the incinerator and possibly presenting other environmental consequences. To be compatible with medical solutions, it is desirable that the probe material be free of or possess a minimum content of low molecular weight additives such as plasticizers, stabilizers, and the like. These components could be extracted by the therapeutic solutions that have contact with the material. The additives may react with the therapeutic agents or otherwise render the solution ineffective. This is especially problematic in bio-tec drug formulations where the concentration of the drug is measured in parts per million (ppm) and not in percentages of weight or volume. Even tiny losses of the drug bio-tec can render the formulation unusable. Since the dosage of bio-tec formulations may cost several thousand dollars, it is imperative that the dose is not changed. Ligament properties are important because medical probes are often connected to the entrance of an I.V. or a continuous ambulatory peritoneal dialysis container or other joint components with a fluid administration set. Therefore, it is necessary that the probe be able to bind to polymers such as poly esters, polycarbonates and polyolefins that are commonly used in the manufacture of such joints. The autoclavable medical probe must be flexible. Most autoclavable medical probes are produced with polyvinyl chloride. Because polyvinyl chloride is a rigid polymer, you have to add low molecular weight components to make polyvinyl chloride flexible. However, these plasticizers can be extracted from the probe by the fluid. For this reason, and due to the difficulties encountered in the incineration of chloride and polyvinyl, there is a need to replace the medical probe of polyvinyl chloride. The probe must also show very little ability to stay spiral and a low elastic constant after the autoclave. The quality of staying spiral is the phenomenon where the probe maintains its helical (spiral) shape after it is unraveled from an axis. The ability to stay spiral is problematic because it makes the probe physically shorter. Aside, a probe that demonstrates the quality of staying spiral has a potential energy when it straightens. When the probe is used to connect an I.V. or from CAPD to a patient, the potential energy creates an undesirable jerking force at the patient's exit site. Jerking force may cause pain or discomfort to the patient, and eventually, there may be infection. There are no polyvinyl chloride probes, however these probes are not suitable for applications where the flexibility and sealing power depend on the elastic properties of the probe. For example, styrene-ethylene-butane-styrene-modified oil (SEBS), such as Kraton G2705 manufactured by the Shell Chemical Company, has the necessary flexibility, but probes produced from Kraton G2705 can not be manufactured at a high speed due to the poor melting strength caused by phase separation at the ejection temperature. This phase separation causes the Kraton G2705 probes to crack when melted. Thus, when the probe produced from Kraton G2705 is ejected at commercial speeds, it breaks into pieces. The U.S. Patent No. 4,041,103 (Davison et al.) And U.S. Pat. No. 4,429,076 (Saito et al.) Discloses non-polyvinyl chloride polymer blends of a polyamide and SEBS. However, the polymeric materials of these patents generally do not comply with providing the physical properties required for medical probes. For example, Davison, et al. discloses illustrative mixtures of various combinations of block copolymers, with nylon, and in some cases other components such as copolymer poly- and vinyl acetate. The majority of the mixtures of Davison et al. specify the use of nylon 6. The polymeric materials of Davison et al. They are more suitable for end uses where they are subjected to high temperature oxidation environments such as automotive under-the-hood applications or electrical power cable applications (Column 6, line 67 to Column 7, line 3). Saito et al. reveals polymeric material that has from 1% to 99% SEBS and the polyamide balance. The polymeric compositions of Saito et al. typically they are automotive, electrical, mechanical parts, medical equipment, packaging material and injected or blow molded construction material. (Column 16, lines 46- Others have used SEBS in probes and in films as a component of a mixture, US Patent No. 4,803,102 (Raniere et al.) And US Patent No. 5,356,709 (Woo et al.) Disclose structures. multi-layer where a mixture of SEBS is used as a layer inside multilayer structures, for example, Raniere et al., reveals a multilayer packaging film.The outer layer or heat seal layer is produced with a mixture of not less than 10% by weight of polypropylene and up to 90% by weight of SEBS.Similarly, Woo et al. reveals a multilayer probe.The outer layer of the probe is produced from a mixture of 40 to 99% by weight of polypropylene and 1 to 60% by weight of SEBS Ni Raniere et al., and Woo et al., reveals the use of a mixture of polypropylene and SEBS as a monolayer probe, and neither Raniere et al. nor Woo et al. al. reveals the use of a high melting strength polypropylene in its polypropylene and SEBS layer. resenta to solve these and other problems.

The disclosure of the invention The present invention provides a polyvinyl chloride monolayer-free medical probe. The medical probe of the present invention exhibits many features that are required in the medical industry including a comparable flexibility with plasticized polyvinyl chloride, minimal powder adhesion, poor quality of maintaining the spiral shape, and the ability to seal to other components. The medical probe disclosed here is able to withstand the temperatures and pressures that are reached during a standard autoclave process without significant thermal degradation. The polymeric material is composed of a mixture of a reagent that increases the melting strength of a polyolefin and preferably a homopolymer or a copolymer of a polypropylene having a melt-flow index greater than 10 grams / 10 min. and a second component preferably a copolymer of styrene and hydrocarbon. The second most preferred component is selected from a group consisting of selectively hydrogenated block copolymers of an aromatic hydrocarbon vinyl and a conjugated diene and a selectively hydrogenated block copolymer of an aromatic hydrocarbon vinyl and a conjugated diene which has been fused to a alpha, beta-olenifical monocarboxylic or unsaturated dicarboxylic acid reagent. This second compound is preferably a hydrogenated styrene-butadiene-styrene resulting in styrene-ethylene-butane-styrene (SBS). The preferred one is a modified oil SEBS such as the commercially available KRATON G2705 from the Shell Chemical Company. Other advantages and aspects of the present invention will become apparent upon reading the following descriptions of the drawings and a detailed description of the invention.

Brief Description of the Drawings Figure 1 demonstrates the current invention connected to several rigid containers.

The Best Method for Carrying Out the Invention While the invention can be incorporated in several different ways, through the drawings and as will be described below, preferred embodiments of the invention with the understanding that the current disclosure should be considered as an example. of the principles of the invention and its intention is not to limit the broad aspect of the invention to the illustrated embodiments.

The current invention is comprised of an autoclavable monolayer medical probe that is suitable for high velocity (at least 50 ft / min) ejection and adheres to components made of polycarbonate poly esters, polyolefins, polyolefin blends and methods for use the probe. The medical probe is produced from a mixture of an agent that increases the fusion force in an amount of 1% to 10% by weight and a styrene-hydrocarbon copolymer in an amount of 90% to 99% by weight. The reagent that increases the melting strength is a polyolefin and preferably a polypropylene homopolymer or copolymer having a melt / flow index in the range of 10 grams / 10 minutes to 800 grams / 10 minutes, preferably 30 grams / 10 minutes. at 200 grams / 10 min., or any range or combination of ranges within these. This component is a polypropylene homopolymer or copolymer having a high melting strength characteristic. Methods for preparing polypropylenes having a high melt strength characteristic have been described in U.S. Pat. 4,916,198; 5,047,485; 5,605,936 which are hereby incorporated by reference and as part of this document. One of these methods includes the irradiation of a linear propylene polymer in an environment in which the active oxygen concentration is about 15% by volume energy radiation by high energy ionization at a dose of 1 to 104 megarads per minute during a enough time for a substantial amount of chain break of the linear propylene polymer to occur, but not enough to cause the material to become gelatinous. The irradiation is maintained until a significant amount of branched long chains have been formed. The material is then treated to substantially deactivate all free radicals present in the irradiated material. Polypropylene copolymers preferably contain a suitable co-monomer component within the range of 1-15% by weight. Suitable monomers include those monomers selected from a group consisting of alpha olefins having from 1 to 10 carbon atoms. Useful copolymers include random copolymers of propylene with ethylene, where the ethylene content is within the range of 1 to 6%, and preferably 2 to 4%, or any rank or combination of ranges within these. In addition, random copolymers of propylene alpha-olefin (PPE) are especially useful. Preferably, random copolymer alpha-olefins will have a narrow molecular weight range. This component that increases the fusion force increases the strength of the mixture at melting temperatures and allows the mixture to be expelled at commercial speeds. In addition, apart from having poor melting strength, powder adheres to the surface of finished products made from the styrene copolymers and hydrocarbon. However, when they are linked with or modified with polypropylene homopolymers or copolymers of high melting strength and high melt flow, the deficiency is eliminated. The styrene-hydrocarbon copolymer is preferably selected from the group of selectively hydrogenated block copolymers of an aromatic hydrocarbon vinyl and a diene and a selectively hydrogenated block copolymer of an aromatic hydrocarbon vinyl and a conjugated diene to which an alpha acid reagent has been fused. , unsaturated monocarboxylic or carboxylic beta-olenifical.

The selectively hydrogenated block copolymers can be chosen from diblock, triblock, multiblock, polyblock starblock copolymers, or aggregate block. These block copolymers can be prepared by any of the well-known block polymerization or block copolymerization procedures such as those presented in U.S. Pat. Nos. 3,251,905; 3,390,207; and 4,219,627 which are incorporated by reference in this document. The vinyl aromatic hydrocarbons that are used to prepare the copolymer include styrene, and the various substituted styrenes including o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, 1,3-dimethylstyrene, alpha-methylstyrene, beta-methylstyrene, isopropylstyrene, 2,3-dirnethylstyrene, o-chlorostyrene, p-chlorostyrene, o-bromostyrene, and 2-chloro-4-methylstyrene. Conjugated designs include those that preferably contain from 2 to 30 carbon atoms. Conjugated designs of this type may be selected from the group containing 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, chloroprene, 1,3-pentadiene, and 1,3- hexadiene. The styrene and hydrocarbon copolymer can be composed of a styrene-isoprene-styrene block copolymer. A hydrogenated styrene-bitadiene-styrene (SBS) resulting in a styrene-ethylene-butane-styrene (SEBS) is very preferable. The most preferable is an oil-modified SEBS copolymer. The amount of oil added to the SEBS is preferably in the range of between 5% and 40% by weight of mineral oil, polybutene oil, or a similar one more preferably 30% by weight of a mineral oil, polybutene oil or any similar or any rank or combination of ranges contained within it. An oil-modified SEBS copolymer of these specifications is the commercially available KRATON G 2705 from the Shell Chemical Company.

Another suitable hydrocarbon styrene copolymer includes the selectively hydrogenated block copolymers of an aromatic hydrocarbon vinyl and a conjugated diene to which an unsaturated alpha, beta-oleic acid monocarboxylic or dicarboxylic acid reagent has been fused. Carboxylic acids include derivatives of such as anhydrides, umides, metal salts, and esters. The binding can be carried out by melting or mixing the solution of a hydrogenated block copolymer and the carboxylic reagent in the presence of a free radical initiator. Figure 1 demonstrates a medical probe of a layer 10 of the current invention made from the mixture of the current invention. The medical probe 10 preferably mixed in a tumbler and ejected by a high mix cylinder with a tight cylinder pack. The probe 10 preferably has an inner diameter in the range of 0.08 inches to 0.5 inches, most preferably within the range of 0.1 inch to 0.30 inches, or any range or combination of ranges contained within it. The first component of the polypropylene homopolymer or copolymer has to be dispersed in the styrene and hydrocarbon copolymer matrix to ensure the fusion force for the expulsion of the probe. It is believed that a portion of the first component flows to the surface of the probe in such a way that the medical probe has a brighter surface. With the presence of the first component on the surface of the medical probe, the adhesion of powder is largely reduced. Figure 1 also demonstrates medical probe 10 of the current invention sealed to a CAPD connector 12. The probe 10 of the present invention exhibits sufficient elastic properties to seal polymeric containers.

In particular, during steam sterilization, the probe of the current invention will seal itself or be mechanically or chemically bonded to containers, couplings 14, and Y-joint connectors 16 produced from a polymeric material without the use of adhesives or solvents. . Such polymeric materials include polycarbonates, poly esters and polypropylenes as well as linkages such as those disclosed in Patent Application No. 08/153, 823. During the autoclave process, the probe and the container are subjected to sterilizing steam that has a temperature of 121 ° C and high pressures. These conditions are sufficient to fuse and soften a portion of the polymer mixture and cause the mixture to fuse to the container and a ligation is formed therewith. The probes of the present invention have a modulus of elasticity of preference less than 10,000 psi, and more preferably within the range of 500 to 5,000 psi, or any range or combination of ranges within it. In addition, the medical probe will preferably meet the following physical requirements: spiral shape recovery greater than 30%; more preferably greater than 50% and of greater preference greater than 70% or any rank or combination of ranges within it; shrinkage less than 10%, more preferably less than 5% and most preferably less than 1% or any rank or combination of ranges within it; and a self-giving strength of preference less than 50,000 psi, more preferably within the range of 25,000 to 45,000 psi or any rank or combination of ranges within it.

EXAMPLES Example 1 The medical probe was extracted from a Shell Kraton G2705 styrene-ethylene-butane-styrene material. The ejector that was used was an ejector of standard mixer cylinder. The medical probe was ejected at approximately 14 feet / minute using an open water tank with the following ejection temperatures: zone 1 at 370 ° F, zone 2 at 380 ° F, zone 3 at 390 ° F, area 4 to 400 ° F and the die lathe at 400 ° F. Spiral shape recovery, spring constant, shrinkage, modulus of elasticity, optical clarity and high-speed productivity are summarized in Table 1.

Example 2 The probes from Example 2 to Example 5 were ejected at approximately 24 feet / minute, using a vacuum gauge, and the expeller was maintained at a constant temperature in all zones and given. A Dutch woven screen cushion was used. A polymeric material was produced from 99% Shell Kraton G2705 and 1% polypropylene (Montell PF611, 40 MFI). The probe was made using a similar ejector and at speeds similar to the process in Example 1. The probe was produced in a vacuum meter instead of in open water. At 360 ° F the probe had poor surface appearance. The appearance of the surface was optimized to 370 ° F. As the temperature increased to 375 ° F and more, a localized reduction in the diameter dimension of the probe or "encuellecimiento" occurred. The appearance of the surface increased in brightness as the temperature increased. The physical and optical properties of the probe are summarized in Table 1.

Example 3 In Example 3, the composition of the polymeric material was modified to 98% Shell Kraton G2705 and 2% polypropylene (Montell PF611, 40MFI). The probe was produced in a manner identical to Example 2. At 360 ° F, the probe demonstrated a poor surface appearance. At 375 ° F and above, the probe began to "collapse". Again, as the temperature increased, the surface became brighter. Table 1 summarizes the physical properties and optical quality. A large-scale test was done at 50 feet / minute with a double Dutch fabric screen cushion. The window of expulsion temperature was significantly extended and the phenomenon of "encuellecimiento" was not observed.

Example 4 In Example 4, the composition of the polymeric material was modified to 95% Shell Kraton G2705 and 5% polypropylene (MonteU PF611, 40MFT). The probe was produced in a manner identical to Example 2. At 390 ° F, the appearance of the probe surface had the desired brightness. At 395 ° F the probe started "encuellecer". Again, the more the temperature increased, the surface became brighter. Table 1 summarizes the results of example 4.

Example 5 In Example 5, the amount of polypropylene added to the polymeric material was increased to 10%; the balance of the polymeric material was Shell Kraton G2705.

No phenomenon of "encuellecimiento" was observed at temperatures as high as 420 ° F. Again, Table 1 summarizes the results of this test.

TABLE 1: EXAMPLES Without the addition of polypropylene to the oil-modified SEBS, it was difficult to expel the material at a commercially acceptable rate because phase separation and melt fracture occurred. The result was a probe that broke into pieces while being ejected. The addition of up to 10% by weight of polypropylene to the oil-modified SEBS increased the melting strength and the melt-flow index of polymeric material so that a suitable, autoclavable medical probe could be produced at a commercially acceptable rate. , of low module.

While specific expressions have been illustrated and described herein, numerous modifications are possible without departing from the spirit of the invention, and the scope of protection is limited only by the scope of the appended claims.

Claims (15)

1. CLAIMS We claim: 1. A monolayer medical probe capable of being sterilized with steam that is composed of: a mixture of a reagent to increase the fusion strength of a polypropylene homopolymer or copolymer having a melt-flow index greater than 10 grams / 10 minutes and in a weight amount from 1-10% and 90-99% by weight of a second component selected from a group of (i) a selectively hydrogenated block copolymer of a hydrocarbon vinyl aromatic and a conjugated diene and ( ii) a selectively hydrogenated block copolymer of an aromatic hydrocarbon vinyl and a conjugated diene to which an unsaturated alpha, beta-olefinic monocarboxylic or dicarboxylic acid reagent has been fused.
2. 2. The probe of claim 1 within which the second component is a styrene-ethylene-butane-styrene block copolymer.
3. 3. The probe of claim 2 wherein the styrene-ethylene-butane-styrene block copolymer is modified with 5-40% by weight of an oil.
4. The probe of claim 1 within which the second component is a styrene-ethylene-butane-styrene block copolymer composed of 5-40% by oil.
5. 5. The probe of claim 1 wherein the melt strength increase reagent has a melt-flow index of at least 40 grams / 10 minutes.
6. 6. The probe of claim 1 within which the probe has the following physical characteristics: A recovery of the spiral shape of at least 30%; A modulus of elasticity from around 400 psi to 10,000 psi; A force of less than 50,000 psi.
7. 7. The probe of claim 1 wherein the probe has a modulus of elasticity less than 3,500 psi.
8. 8. The probe of claim 1 wherein the polypropylene homopolymer or copolymer is high in modified fusion strength.
9. 9. The probe of claim 1 wherein the probe has a translucent clarity after the autoclave.
10. 10. A method for ligating a polymeric container is comprised in the steps: providing a probe with the reagent for increasing the melting strength of a mixture of a homopolymer and polypropylene copolymer having a melt-flow index greater than 10 grams / 10 minutes and a second component selected from a group of selectively hydrogenated block copolymers of a hydrocarbon vinyl aromatic and a conjugated design and a selectively hydrogenated block copolymer of an aromatic hydrocarbon vinyl and a conjugated diene to which an alpha acid reagent has been fused, unsaturated monocarboxylic or dicarboxylic beta-olefin which provides a polymeric container of a polar molecule; which contacts the probe to the container to form a game; and, which heats the game in the presence of steam to bind the probe to the container.
11. 11. The method of claim 11 wherein the polymeric container is produced from an ally polypropylene having a component such as a melting point of the temperature of the autoclave.
12. 12. The method of claim 11 wherein the polymeric container is produced from a polycarbonate.
13. 13. The method of claim 11 wherein the polymeric container is produced from a polypropylene.
14. 14. The method of claim 11 wherein the probe is composed of 1-10% by weight of polypropylene and 90-99% by weight of styrene-ethylene-butane-styrene modified by oil.
15. 15. The method of claim 14 wherein the styrene-ethylene-butane-styrene modified by oil has 5-40% by weight of a mineral oil.