Patent Description:
Flexible tube is used in a variety of industries and household products. In particular, flexible tube is often used in healthcare products, such as catheters and other medical or biopharm tubing. In addition, flexible tube is used in household products such as hydration products, including portable and potable water containers. Conventional tubes for such applications are made using plasticized polyvinyl chloride.

Polyvinyl chloride based products have been used widely in medical fields for healthcare products such as films, gloves, bags, catheters and tubing. In particular, most of the disposable medical devices are produced from plasticized flexible PVC. To form flexible PVC products, manufacturers typically use plasticizers or processing aids, such as di-<NUM>-ethylhexylphthalate (DEHP). <CIT> relates to a novel PVC compound that may be used to manufacture plastic film and tubing used to make a variety of blood bags.

Since conventional tubes use a PVC-based flexible composition and such tube is commonly used to transfer or handle fluids of medicines, foods and beverages, certain formulations including processing aids or plasticizers, such as di-<NUM>-ethylhexylphthalate (DEHP), may elute into the transfer stream and possibly end up in the body of consumers and thus increase their risk of exposure to plasticizers.

Accordingly, an improved flexible tube would be desirable.

In an embodiment, a flexible tube as defined in claim <NUM> includes a polymer composition of a poly vinyl chloride having a molecular weight greater than about <NUM> inherent viscosity (IV) and a bio-based plasticizer.

In another embodiment, a method of forming a flexible tube as defined in claim <NUM> is provided. The method includes compounding a poly vinyl chloride having a molecular weight greater than about <NUM> inherent viscosity (IV) with a bio-based plasticizer to form a polymer composition; and extruding the polymer composition into the flexible tube.

<FIG> include graphical illustrations of pump life results for exemplary blends of flexible tubes with a bio-based plasticizer and a phthalate plasticizer.

The following description in combination with the figures is provided to assist in understanding the teachings disclosed herein. The following discussion will focus on specific implementations and embodiments of the teachings. This focus is provided to assist in describing the teachings and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise.

The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent not described herein, many details regarding specific materials and processing acts are conventional and may be found in reference books and other sources within the structural arts and corresponding manufacturing arts.

A flexible tube includes a polymer composition including a polymer and a bio-based plasticizer as defined in claim <NUM>. The polymer includes a thermoplastic elastomer. The bio-based plasticizer provides a non-toxic source suitable for thermoplastic elastomer formulations. The tube including the polymer and bio-based plasticizer is flexible with a surface that has low levels of extractables in a fluid environment and improved mechanical properties compared to conventionally available thermoplastic elastomer formulations.

The flexible tube includes the polymer formed of the thermoplastic elastomer. As such, the thermoplastic elastomer may include polyethylene, polypropylene, polyvinylchloride (PVC), polyvinylidene chloride (PVDC), polyvinylflouride (PVF), polyvinylidenefluoride (PVDF), polytetrafluoroethylene (PTFE), polychlorotrifluoroethylene (PCTFE), or combinations thereof. In a particular embodiment, the polymer is polyvinyl chloride. In a more particular embodiment, the polyvinyl chloride is a homopolymer. For instance, the homopolymer of polyvinyl chloride includes the repeating monomeric units of a vinyl chloride. As used herein "homopolymer" describes polyvinyl chloride having at least <NUM>%, or even at least <NUM>% of vinyl chloride monomeric repeating units based on the total polyvinyl chloride chemical composition.

In an embodiment, the thermoplastic elastomer has a desirable molecular weight. For instance, the thermoplastic elastomer has a desirable molecular weight for ease of processing with the plasticizer. The thermoplastic elastomer has a molecular weight greater than about <NUM> inherent viscosity (IV), such as greater than about <NUM> inherent viscosity, or even greater than about <NUM> inherent viscosity, as measured by ASTM-D1243. As such, the thermoplastic elastomer is a polyvinyl chloride having an inherent viscosity greater than <NUM>, as measured by ASTM-D1243. In an exemplary embodiment, the thermoplastic elastomer is a high molecular weight thermoplastic elastomer. "High molecular weight" as used herein refers to a thermoplastic elastomer having an inherent viscosity greater than about <NUM>, such as greater than about <NUM>.

The polymer composition further includes a plasticizer, namely a bio-based plasticizer. The plasticizer is added to the thermoplastic elastomer to increase the flexibility of the polymer composition without chemically reacting with the monomer or monomers of the thermoplastic elastomer, i.e. decrease the shore A durometer of the resulting polymer composition. A "bio-based" plasticizer as used herein refers to a plasticizer that is naturally derived, such as plant based. Any suitable bio-based plasticizer is envisioned. A suitable bio-based plasticizer is, for example, derived from a vegetable based material such as a castor oil, a soybean oil, linseed oil, tall oil, the like, or a combination thereof. In an embodiment, the bio-based plasticizer is derived from a castor oil, such as a fully hydrogenated castor oil. A fully hydrogenated castor oil also is known as castor wax. "Fully hydrogenated" as used herein refers to a castor oil that has been exposed to hydrogen, typically in presence of a catalyst. In a particular embodiment, a fully hydrogenated castor oil refers to a castor oil that has been exposed to hydrogen, typically in presence of a catalyst, leaving no unsaturated carbon-carbon bonds. In an embodiment, the bio-based plasticizer includes a fully hydrogenated castor oil that is acetylated to provide an acetylated monoglyceride. Typically, the acetylated monoglyceride is about <NUM>% by weight of the composition of the bio-based plasticizer. An exemplary castor oil bio-based plasticizer is commercially available as Grinsted® Soft-n-Safe, a fully hydrogenated castor oil that is acetylated, from Danisco based in Brabrand, Denmark. Other exemplary bio-based plasticizers include, but are not limited to, Plasthall PR-<NUM> and LCOA commercially available from The Hallstar Company based in Chicago, IL; SGP9100D and SGP2100D commercially available from Segetis, Inc. based in Golden Valley, MN; Ecolibrium commercially available from The Dow Chemical Company; Rymsaplas Bio525 and Rymsaplas T400 commercially available from Resinas y Materials based in Bangor, Maine; and PATPLAS Bio-<NUM> commercially available from Pat Products, Inc. based in Bangor, Maine.

The bio-based plasticizer is included in the polymer composition in an amount to improve processability of the thermoplastic elastomer. As stated, the bio-based plasticizer is compounded with the thermoplastic elastomer to decrease the shore A durometer and increase the flexibility of the resulting compounded article. The bio-based plasticizer may be present at an amount of greater than about <NUM>% by weight based on the total weight of the polymer composition.

The bio-based plasticizer has further desirable properties when compounded with the thermoplastic elastomer. For instance, the bio-based plasticizer has a volatility after <NUM> hours at <NUM> (<NUM>°F) of less than about <NUM>%, as measured by ASTM-D1203. In comparison, a phthalate plasticizer, such as di-<NUM>-ethylhexyl phthalate (DEHP), has a volatility after <NUM> hours at <NUM> (<NUM>°F) of less than about <NUM>%, as measured by ASTM-D1203. The bio-based plasticizer has lower volatility during the compounding process of the bio-based plasticizer and the thermoplastic elastomer compared to the phthalate plasticizer. In an embodiment, the bio-based plasticizer increases the efficacy of a flexible tube when used with a peristaltic pump. Further, the bio-based plasticizer compound has a water extraction resistance of less than about <NUM>% weight loss when tested after a <NUM> hour boiling water test. In comparison, a phthalate plasticizer, such as di-<NUM>-ethylhexyl phthalate (DEHP), has a water extraction resistance of about <NUM>% weight loss when tested after a <NUM> hour boiling water test, as measured by ASTM-D471. The water extraction resistance demonstrates that the bio-based plasticizer migrates out of the thermoplastic elastomer into its surrounding environment less than the phthalate plasticizer. Properties such as volatility and water extraction resistance are demonstrative of desirable properties of the bio-based plasticizer compared to the phthalate plasticizer.

In an exemplary embodiment, the polymer composition further includes any additive envisioned such as a lubricant, a filler, a secondary plasticizer, an antioxidant, a colorant, or any combination thereof. Exemplary lubricants include silicone oil, waxes, slip aids, antiblock agents, the like, or any combination thereof. Exemplary lubricants further include silicone grafted polyolefin, polyethylene or polypropylene waxes, Oleic acid amide, erucamide, stearate, fatty acid esters, the like, or any combination thereof. Typically, the lubricant may be present at less than about <NUM>% by weight of the total weight of the polymer composition. In an embodiment, the lubricant may be present at less than about <NUM>% by weight of the total weight of the polymer composition. Exemplary antioxidants include phenolic, hindered amine antioxidants. Exemplary fillers include calcium carbonate, talc, radio-opaque fillers such as barium sulfate, bismuth oxychloride, any combinations thereof, and the like. Exemplary secondary plasticizers include any known plasticizers such as mineral oils, soybean oil, such as epoxidized soybean oil, the like, or any combination thereof. Typically, an additive may be present at an amount of not greater than about <NUM>% by weight of the total weight of the polymer composition, such as not greater than about <NUM>% by weight of the total weight of the polymer composition, or even not greater than about <NUM>% by weight of the total weight of the polymer composition.

In an alternative embodiment, the polymer composition may be substantially free of a lubricant, a filler, a secondary plasticizer, an antioxidant, or combination thereof. Further, the polymer composition is substantially free of an endocrine disrupter, an animal derived additive, or combination thereof. In an embodiment, the polymer composition is substantially free of any phthalate composition. In a particular embodiment, the polymer composition is substantially free of any phthalate plasticizer. "Substantially free" as used herein refers to a polymer composition containing less than about <NUM>% by weight, or even less of any of the aforementioned additives based on the total weight % of the polymer composition. For instance, the polymer composition may consist essentially of the thermoplastic elastomer and the bio-based plasticizer. As used herein, the polymer composition may be substantially free of any additional polymers or materials that may affect the basic and novel characteristics of the polymer composition.

In an embodiment, the flexible tube may be formed by any reasonable means, such as extrusion or injection molding. In an embodiment, the thermoplastic elastomer and bio-based plasticizer may be melt processed by dry blending or compounding. The dry blend may be in powder, granular, or pellet form. In a particular embodiment, to form the flexible tube, pellets of the corresponding monomer or polymer may be compounded with the plasticizer through a co-rotating intermeshing twin-screw extruder, cooled by a water bath, and cut into compound pellets. The flexible article may be made by a continuous compounding process or batch related process. The resulting pellets of the blend are fed into an extruder with a tube die. The tube is extruded through the tube die, the tube having an inner surface that defines a central lumen of the tube. Any cure conditions are envisioned, such as thermal cure.

Once formed, the flexible tube advantageously can withstand sterilization processes. In an embodiment, the flexible tube is sterilized by any method envisioned. Exemplary sterilization methods include steam, gamma, ethylene oxide, E-beam techniques, combinations thereof, and the like. In a particular embodiment, the flexible tube is sterilized by steam sterilization. In an exemplary embodiment, the flexible tube is heat-resistant to steam sterilization at temperatures up to about <NUM> for a time of up to about <NUM> minutes. In an embodiment, the flexible tube is heat resistant to steam sterilization at temperatures of up to about <NUM> for a time of up to about <NUM> minutes. In an embodiment, the flexible tube may be sterilized via gamma sterilization of up to about 50kGy, such as at least about <NUM> kGy, or even at least about <NUM> kGy.

The present embodiments can produce articles having desirable mechanical properties. In particular, the resulting blends have desirable flexibility, substantial clarity or translucency, and the like. Flexibility of the final tube is typically with a shore A of about <NUM> to about <NUM>, such as about <NUM> to about <NUM>. Clarity of the flexible tube is checked visually and classified into four levels in terms of transparency: clear, translucent, hazy, and opaque. In an embodiment, the flexible tube is not opaque and may be clear or translucent. In a particular embodiment, the flexible tube is clear. In a more particular embodiment, the flexible tube has a light transmission greater than about <NUM>%, such as greater than about <NUM>%, or even greater than about <NUM>% in the visible light wavelength range.

In an embodiment, the flexible material when formed into a tube has properties such as desirable burst pressure, pump life, and flex fatigue resistance. For instance, the burst pressure of a tube having an average inner diameter of <NUM> (<NUM> inches) and an average outer diameter of <NUM> (<NUM> inches) is greater than about <NUM> MPa (<NUM> psi) at a temperature of <NUM> (<NUM>°F), as measured by ASTM-D1599. In an embodiment, the tube of the present disclosure has desirable pump life. For instance, the tube has a pump life of at least about <NUM> hours, at least about <NUM> hours, at least about <NUM> hours, or even greater on a Masterflex peristaltic pump using an L/S <NUM> standard pump head at <NUM> rpm with water as a medium, room temperature at <NUM> MPa (<NUM> psi) backpressure. The flexible tube of the thermoplastic elastomer, such as a polyvinyl chloride, having the bio-based plasticizer has a pump life greater than about <NUM>% to about <NUM>%, or even greater in comparison to a polyvinyl chloride tube with a phthalate plasticizer. In an embodiment, the tube having the bio-based plasticizer has a desirable flex fatigue resistance at least comparable to or even better than a polyvinyl chloride tube with a phthalate plasticizer.

Further, the flexible tube has desirable mechanical and physical properties such as tensile strength, elongation, and tensile modulus. For instance, the flexible tube has a tensile strength of at least about <NUM> MPa (<NUM> psi), at least about <NUM> MPa (<NUM> psi), at least about <NUM> MPa (<NUM> psi), or even greater, as measured by ASTM-D412. In an embodiment, the flexible tube has an elongation of at least about <NUM>%, such as at least about <NUM>%, such as at least about <NUM>%, or even greater, as measured by ASTM-D412. In an embodiment, the flexible tube has a tensile modulus at <NUM>% elongation of at least about <NUM> MPa (<NUM> psi), such as at least about <NUM> MPa (<NUM> psi), such as at least about <NUM> MPa (<NUM> psi), or even greater, as measured by ASTM-D412.

In exemplary embodiments, the flexible material disclosed above in relation to a flexible tube can be used in a variety of applications. Applications for the flexible tube are numerous. In particular, the non-toxic nature of the flexible tube makes the flexible tube useful for any application where toxicity is undesired. For instance, the flexible tube has potential for FDA, ADCF, USP Class VI, NSF, European Pharmacopoeia compliant, United States Pharmacopoeia (USP) compliant, USP physiochemical compliant, ISO <NUM> Standard for evaluating biocompatibility of a medical device, and other regulatory approvals. In a particular embodiment, the flexible tube is non-cytotoxic, non-hemolytic, non-pyrogenic, animal-derived component-free, non-mutagenic, non-bacteriostatic, non-fungistatic, or any combination thereof.

For example, the flexible tube may be used in applications such as industrial, medical applications, health care, biopharmaceutical, drinking water, food & beverage applications, dairy applications, laboratory applications, FDA applications, and the like. In an exemplary embodiment, the flexible tube may be used in applications such as a hydration tube for sports and entertainment equipment, a fluid transfer tube in food and beverage processing equipment, a fluid transfer tube in medical and health care, biopharmaceutical manufacturing equipment, and peristaltic pump tube for medical, lab and biopharmaceutical applications. In a particular embodiment, the flexible tube may be used in a peristaltic pump. In an exemplary embodiment, the tube may be part of molded assemblies typically used in biopharmaceutical applications such as pumping, bioreactor processing, sampling, filling, and the like. In an embodiment, the tube may be configured into a braided product or multilayer product for tubing. In an embodiment, the tube may be used for high pressure pump applications. "High pressure" as used herein refers to a pressure of at least about <NUM> MPa (<NUM> psi), or greater. In an embodiment, "high pressure" is at a pressure of about <NUM> MPa (<NUM> psi) and about <NUM> MPa (<NUM> psi).

In a particular embodiment, a fluid source, such as a container, reactor, reservoir, tank, or bag, is coupled to a flexible tube. The flexible tube may engage a pump, fitting, valve, dispenser, or another container, reactor, reservoir, tank, or bag. In an example, the flexible tube may be coupled to a water container and may have a dispenser fitting on the distal end. In another example, the flexible tube may be coupled to a fluid bag and coupled to a valve at the distal end. In a further example, the flexible tube may be coupled to a container, be engaged in a pump, and be coupled to a second container at a distal end.

Many different aspects and embodiments are possible. Some of those aspects and embodiments are described herein. After reading this specification, skilled artisans will appreciate that those aspects and embodiments are only illustrative and do not limit the scope of the present invention.

The following examples are provided to better disclose and teach processes and compositions of the present invention.

A number of exemplary tubes are extruded. There are six compounds, E-LFL, LFL, E-<NUM>, R-<NUM>, B-<NUM>-4X (19EX), and B-<NUM>-4X. The compositions are as follows:.

Results for testing on pump life can be seen in <FIG>. Tubing is extruded into <NUM> different sizes ranging in inner diameter (ID) and outer diameter (OD). Unless otherwise indicated, the tubes are tested for pump life on a Masterflex peristaltic pump using an L/S <NUM> standard pump head at <NUM> rpm with water as a medium at room temperature.

The Figures clearly demonstrate that in all instances, the polyvinyl chloride tubes containing the bio-based plasticizer, SNS, have an increase in pump life compared to the tubes prepared with DEHP. Unexpectedly, the increase in pump life is greater than about <NUM>% to about <NUM>%, or even greater in comparison to a polyvinyl chloride tube with a phthalate plasticizer.

Claim 1:
A flexible tube comprising a polymer composition of a poly vinyl chloride having a molecular weight greater than <NUM> inherent viscosity (IV) as measured by ASTM-D1243 and a bio-based plasticizer, wherein the bio-based plasticizer is present at an amount greater than <NUM>% by weight of the total weight of the polymer composition, wherein the flexible tube has an inner surface that defines a central lumen of the flexible tube for fluid flow, wherein the flexible tube has a pump life of at least <NUM> hours as measured at <NUM> RPM using a Masterflex peristaltic pump containing a L/S <NUM> standard pump head at <NUM> MPa (<NUM> psi).