Hybrid coaxial tube

Abstract

A hybrid tube construction for use in, e.g., industrial or hydraulic hoses is described, such as industrial hose products used in data center cooling applications. The hybrid tube generally includes coaxially aligned interior tube and outer tube layers. The interior tube layer of the hybrid tube is a functional layer having chemical resistance to the fluid to be conveyed within the hybrid tube, while the outer tube layer is designed to provide flexibility, strength, and resistance to environmental exposure typical of data center cooling applications. Different compositions of thermoplastic vulcanizates may be used for the interior tube layer and the outer tube layer to provide a hybrid tube with the desired properties, characteristics, and functionality.

Description

HYBRID COAXIAL TUBECROSS REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 728,574, filed December 5, 2024, and U.S. Provisional Patent Application No. 63 / 917,732, filed November 14, 2025, both of which are hereby incorporated by reference in their entirety.TECHNICAL FIELD

[0002] The present application relates to hybrid tube constructions for use in, for example, industrial hose products, such as industrial hose products used in data center cooling applications. The hybrid tube includes an interior functional tube layer designed for at least chemical resistance to conveyed fluids. The interior tube layer may also be designed to provide an interior surface with low surface energy. The hybrid tube further includes an outer tube layer formed over the interior functional tube layer to provide the hybrid tube with at least flexibility and strength. The outer tube layer may also be designed to be resistant to environmental exposure typical of certain applications, such as environmental exposure in data center cooling applications. In some embodiments, the hybrid tube may be free of reinforcement and / or cover layers.BACKGROUND

[0003] In data center cooling applications, industrial hoses may form part of a cooling system put in place to cool computing equipment that is running continuously and may therefore become very hot. Computing equipment that may require active and continuous cooling includes central processing units (CPU), graphics processing units (GPU), and servers. Without such cooling systems, computing equipment may overheat and malfunction or shut down. Some data center cooling systems therefore use a system of hoses and cold plates to transfer heat away from the computing equipment, sometimes referred to as direct to chip cooling systems. In some direct to chip cooling systems, cold plates are placed directly against computing equipment requiring cooling. Within the coldplates, a series of tubes are provided through which a heat transfer fluid is flowed. The heat transfer fluid takes up the heat from the computing equipment and carries the heat away to thereby help cool the computing equipment.

[0004] In order to be useful in a data center cooling system, the tubing used for conveying heat transfer fluid should meet several criteria. For example, the interior surface of the layer should not degrade from contact with the conveyed fluid (which in some cases is a mixture of water and glycol), the tubing should have good resistance to the high temperature environment of data centers, the tubing should be resistant to environmental exposure typical of data centers (e.g., UV, ozone, etc.), the tubing should be highly flexible so that it can be bent around tight corners and through small spaces typical of data center setups, and the tubing should be resistant to crimping and kinking. Tubing having a relatively small diameter may also be necessary in data center cooling systems, which means the tubing must also be configurable with small internal diameters while still allowing for suitable flow of heat transfer fluid through the tubing and providing sufficient strength against operating pressures.

[0005] Unfortunately, satisfying all of these criteria may be difficult or impossible with a single layer tube construction, and contradictory with a multi-layer tube construction. For example, in a multi-layer tube construction, selecting a material for an outer layer that has good resistance to environmental exposure may require the use of material that is not inherently flexible, and therefore prevents the tubing from being suitable for use in small spaces. Outer layer material having good resistance to environmental exposure may also be prone to kinking or crimping in the tube. Similar issues with respect to reduced bendability and increased kinking may also arise in tubes that use a reinforcement layer between an inner layer and outer layer and / or a cover layer over the outer layer for the purpose of providing additional strength to the composite tube structure.

[0006] Accordingly, a need exists for improved tubing that satisfies most or all of the criteria for an industrial hose suitable for use in data center cooling applications.SUMMARY

[0007] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary, and the foregoing Background, is not intended to identify key aspects or essential aspects of the claimed subject matter. Moreover, this Summary is not intended for use as an aid in determining the scope of the claimed subject matter.

[0008] In some embodiments, a hybrid tube suitable for use in, e.g., data center cooling applications is provided, the hybrid tube including an interior tube layer having a hollow passage extending therethrough, the interior tube layer configured to have chemical resistance to a fluid conveyed through or present in the hollow passage and / or configured to provide an inner surface with low surface energy. The hybrid tube further includes an outer tube layer formed on and coaxially aligned with the interior tube layer, the outer tube layer configured to provide resistance to environmental exposure and resistance to kinking and / or crimping. In some embodiments, the material of the outer layer is a first thermoplastic vulcanizate (TPV) composition, wherein the first TPV composition is selected to provide the hybrid tube with resistance to environmental exposure and resistance to kinking and / or crimping. In some embodiments, the material of the inner layer is a second thermoplastic vulcanizate (TPV) composition, wherein the second TPV composition is different from the first TPV composition. The second TPV composition may be selected to provide the hybrid tube with chemical resistance to the media conveyed through the hybrid tube and / or an inner surface with low surface energy. In some embodiments, the hybrid tube is free of any reinforcement layers positioned between the interior tube layer and the outer tube layer. In some embodiments, the hybrid tube is free of any cover layers positioned on the exterior of the outer tube layer.

[0009] These and other aspects of the technology described herein will be apparent after consideration of the Detailed Description and Figures herein. It is to be understood, however, that the scope of the claimed subject matter shall be determined by the claims as issued and not by whether given subject matter addresses any or all issues noted in the Background or includes any features or aspects recited in the Summary.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Non-limiting and non-exhaustive embodiments of the disclosed technology, including the preferred embodiment, are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0011] FIG. 1 is a perspective view of a portion of a hybrid tube configured in accordance with various embodiments described herein.DETAILED DESCRIPTION

[0012] Embodiments are described more fully below with reference to the accompanying Figures, which form a part hereof and show, by way of illustration, specific exemplary embodiments. These embodiments are disclosed in sufficient detail to enable those skilled in the art to practice the invention. However, embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. The following detailed description is, therefore, not to be taken in a limiting sense.

[0013] Described herein are various embodiments of hybrid tube constructions and methods for making the same, the hybrid tube being well suited for use in, for example, data center cooling applications. Embodiments of the hybrid tube described herein generally include an interior tube layer that defines a hollow passage extending through the length of the tube, and an outer tube layer formed on the interior tube layer and coaxially aligned with the interior tube layer. The interior tube layer is designed to serve as a functional layer that is chemically resistant to fluids that may be conveyed through the hollow passage of the hybrid tube. The interior tube layer may also be designed to provide an inner surface with low surface energy to promote easy flow of fluid through the hybrid tube. The outer tube layer is designed to provide resistance to environmental exposure and resistance to kinking and / or crimping. The combination of these two layers generally provides for a hybrid tube that is capable of conveying fluids typically used in data center cooling applications and which has resistance to environmental exposures typical of data center cooling applications, suitable bendability for data center applications, and resistance to crimping or kinking. Thecombination of these two layers may also eliminate the need for additional layers within the tube, such as reinforcement layers that are typically used between the interior tube layer and the outer tube layer and / or cover layers which are typically applied over the outer tube layer. Eliminating the need for reinforcement layers and / or cover layers can provide benefits such as reductions in cost and improvements in ease of manufacture.

[0014] With reference to FIG. 1 , a hybrid tube 100 configured in accordance with various embodiments described herein is illustrated as including an interior tube layer 110 and an outer tube layer 120 formed on the interior tube layer 110 and aligned coaxially with the interior tube layer 110. The interior tube layer 110 defines a hollow passage 115 that extends through the interior tube layer 110 and provides a passage for fluid to be conveyed through the hybrid tube 100. The specific dimensions of the overall hybrid tube 100, the interior tube layer 110, and the outer tube layer 120 are generally not limited, though in some embodiments, the outer diameter of the interior tube layer 110 should be approximately equal to the interior diameter of the outer tube layer 120 so that the outer tube layer 120 reside directly on and against the interior tube layer 110. In embodiments where the outer diameter of the interior tube layer 110 is approximately equal to the interior diameter of the outer tube layer 120, the exterior surface of the interior tube layer 110 directly contacts the interior surface of the outer tube layer 120, with no intermediate layer or layers (e.g., a reinforcement layer) present between the interior tube layer 110 and the outer tube layer 120.

[0015] In some embodiments, the thickness of the interior tube layer 110 is from 1 to 99% of the total thickness of the hybrid tube 100, such as from about 10 to about 50% of the total thickness of the hybrid tube 100. In such embodiments, the thickness of the interior tube layer 110 may be 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45% or 50% of the overall thickness of the hybrid tube 100, including any ranges therebetween. In some embodiments, the thickness of the interior tube layer 110 is relatively small, such as from about 10% to about 15% of the overall thickness of the hybrid tube 100. In some embodiments, the thickness of the interior tube layer 110 is from 0.8 to 1 .5 mm, such as from 1 .0 to 1 .3 mm. The relatively thin interior tube layer 110 is capable of providing the desired chemical resistance while minimizing the amount of interior tube layer 110 material used in the hybridtube 100, which can thereby reduce the cost of the hybrid tube 100 (such as in instances where the cost of the interior tube layer 110 material is relatively high as compared to other materials used in the hybrid tube 100). The relatively thin interior tube layer 110 may also help to ensure the hybrid tube 100 has good bendability.

[0016] In some embodiments, the thickness of the outer tube layer 120 is from 1 to 99% of the total thickness of the hybrid tube 100, such as from about 50 to about 90% of the total thickness of the hybrid tube 100. In such embodiments, the thickness of the outer tube layer 120 may be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90% of the overall thickness of the hybrid tube 100, including any ranges therebetween. In some embodiments, the thickness of the outer tube layer 120 is relatively large, such as from about 85% to about 90% of the overall thickness of the hybrid tube 100. In some embodiments, the thickness of the outer tube layer 120 is greater than the thickness of the interior tube layer 110. In some embodiments, the thickness of the outer tube layer 120 is in the range of from 1 .3 mm to 2.2 mm, such as from 1 .5 mm to 1 .8 mm or from 1 .8 mm to 2.0 mm). Along with the specific material selected for the outer tube layer 120, the thickness selected for the outer tube layer 120 may be used to ensure the outer tube layer 120 provides the hybrid tube 100 with the desired amount of strength, flexibility, and / or environmental resistance. The thickness of the outer tube layer 120 may also be limited so as to not (or only minimally) negatively impact the bendability of the tube 100.

[0017] As described previously, a primary function of the interior tube layer 110 may be to provide chemical resistance against fluid conveyed within the hybrid tube 100. As such, the material of the interior tube layer 110 should generally be a material that possesses the desired chemical resistance. For example, the material of the interior tube layer 110 may be selected in order to provide sufficient chemical resistance to fluids commonly used in data center cooling applications. One such fluid is a mixture of water and glycol, and as such, the material selected for the interior tube layer 110 may be chemically resistant to a mixture of water and glycol such that the interior tube layer 110 does not degrade when coming into contact with this fluid. In some embodiments, the material of the interior tube layer 110 is selected from a thermoplastic, a thermoset, a ceramic, a metal, and carbon. In more specific embodiments, the material of the interior tube layer 110 is selected from apolyamide, high density polyethylene (HDPE), cross-linked HDPE, cross-linked low density polyethylene (LDPE), an ethylene propylene diene terpolymer (EPDM)Zpolypropylene (PP) blend, polyethylene terephthalate (PET), polyvinylidene fluoride (PVDF), and fluorinated ethylene propylene (FEP). Each of these materials can provide at least adequate chemical resistance as may be required for the specific application of the hybrid tube 100.

[0018] In some embodiments, the interior tube layer 110 is made from a thermoplastic vulcanizate (TPV). TPVs are elastic and thermoplastic processable materials including both a crosslinked rubber and a thermoplastic. In one non-limiting example, TPVs include vulcanized EPDM as the rubber component and polypropylene as the thermoplastic component. Other rubbers that can be used in TPVs include silicone or styrene-based rubber. Other thermoplastics that can be used in TPVs include copolyesters. TPVs form a subcategory within the general group of thermoplastic elastomers (TPE). The rubber phase of TPV is dynamically vulcanized in the blending process, resulting in fully cured rubber particles within the TPV. The thermoplastic component provides a matrix within which the vulcanized rubber is dispersed. Due to the adapted shear and mixing forces used during manufacturing, the rubber phase is very highly dispersed and distributed within the continuous, thermoplastic phase.

[0019] Unlike elastomers, TPV products do not need to be vulcanized during processing, which simplifies the downstream processing operation and thus greatly reduces cycle times. Another advantage with using TPVs is the elimination of cost-intensive reworking steps since the components do not have to be additionally annealed or deburred as is the case with elastomer processing. If cohesive adhesion is not possible, thermoplastic elastomer hybrids can be mechanically anchored by processing in multi-component injection molding. Another advantage is the recyclability of TPV compounds. Sprues and start-up material can be added to the virgin material to a certain percentage. In addition, further additives such as UV stabilizers, fillers, and / or color pigments can be added to achieve the desired material properties.

[0020] Different compositions of TPVs are available to provide TPVs with different attributes. The composition of the TPV may vary by, e.g., the specific rubber used, the specific thermoplastic used, the percentages of rubber and thermoplastic used, and / or thepresence and content of additives. In some embodiments, the composition of the TPV used for the interior tube layer 110 is selected to provide an interior tube layer 110 having strong chemical resistance to the material being conveyed through the interior tube layer 110.

[0021] In some embodiments, the TPV composition used for the interior tube layer is a TPV composition that exhibits low permeation and is therefore characterized as having good chemical resistance. Permeation is generally defined as the penetration of a permeate through a solid. The permeation of a material is measured using SAE J2663, method 2. Under this testing procedure, a hose made from the material to be tested is fluidly attached at one end to a sealed reservoir and capped at the other end. The reservoir is filled with a fluid (e g., DI water or a DI water / glycol mixture) and the reservoir and hose are weighed at the start of testing and then after each 24 hour period to determine weight loss of fluid per day. The weight loss is nominalized by the inner lateral surface area of the hose, providing a unit of measurement for permeation of g / m2 / day. In some embodiments, the TPV composition used has a permeation value of less than 1 g / m2per 24 hours, such as less than 0.9 g / m2per 24 hours, less than 0.8 g / m2per 24 hours, less than 0.7 g / m2per 24 hours, less than 0.6 g / m2per 24 hours, less than 0.5 g / m2per 24 hours, less than 0.6 g / m2per 24 hours, less than 0.5 g / m2per 24 hours, less than 0.4 g / m2per 24 hours, less than 0.3 g / m2per 24 hours, less than 0.2 g / m2per 24 hours, and less than 0.1 g / m2per 24 hours. Examples of commercially available TPV compositions that exhibit a permeation value of less than 1 g / m2per 24 hours and which may therefore be suitable for use for the interior tube layer 110 of the hybrid tube 100 described herein include, but are not limited to, Santoprene® 8201 -60, Santoprene® 8201-70, Santoprene® 8201 -80, and Santoprene® 8201 -90, manufactured by Celanese Corporation of Irving, TX, USA.

[0022] In some embodiments, the TPV composition used for the interior tube layer is a TPV composition that has a low metal oxide content and is therefore characterized as having good chemical resistance. Some TPV compositions include metal oxides as an additive to helps increase material density and / or improve the process of manufacturing the TPV. However, the metal oxides may also be reactive with conveyed fluid, this making TPVs with metal oxide less chemically resistant. In some embodiments, the TPV composition suitable for use in the interior tube layer 110 is a TPV composition that has a metal oxide content ofless than 0.25 wt% of the total TPV composition, such as less than 0.20 wt%, less than 0.15 wt%, less than 0.10 wt%, or less than 0.05 wt%. In some embodiments, the TPV composition used for the interior tube layer 110 is free of metal oxide.

[0023] In some embodiments, the TPV composition used for the interior tube layer is a TPV composition having a high elongation to break measurement and is therefore characterized as having good bendability properties and / or good resistance to crimping and kinking. Elongation to break is a standard mechanical property measurement for TPV compositions in which the original length of the sample is compared to its final length after fracturing. In some embodiments, the TPV composition suitable for use in the interior tube layer is a TPV composition having a elongation to break greater than 500%, such as greater than 525%, greater than 550%, greater than 575%, greater than 600%, or greater than 625%. Each of previously mentioned Santoprene® 8201 -60, Santoprene® 8201-70, Santoprene® 8201 -80, and Santoprene® 8201 -90 have a elongation to break of greater than 500% and can therefore provide both the desired chemical resistance and bendability that are desirable for the interior tube layer 110 of the hybrid tube.

[0024] In some embodiments, the TPV composition used for the interior layer is a TPV composition having a relatively low hardness and is therefore characterized as having good bendability properties and / or good resistance to crimping and kinking. In some embodiments, the TPV composition suitable for use in the interior tube layer 110 has a hardness in the range of 50A to 99A, such as from 65A to 95A. Each of previously mentioned Santoprene® 8201-60, Santoprene® 8201-70, Santoprene® 8201-80, and Santoprene® 8201-90 have a hardness measurement in the range of from 50A to 99A and can therefore provide both the desired chemical resistance and bendability that are desirable for the interior tube layer 110 of the hybrid tube.

[0025] The composition of the TPV used for the interior tube layer 110 may also be selected as one that provides an interior surface of the interior tube layer 110 (i.e., the surface that contacts conveyed media) having a low surface energy. Providing an interior tube layer 110 having an interior surface layer with low surface energy helps to ensure the interior surface is hydrophobic and permits for high flow rates due to lower drag from the absorption mechanism of the conveyed fluid to the interior surface. In data center coolingapplications where the diameter of the hybrid tube 100 may be very small, providing a low surface energy inner surface may allow for good flow of conveyed media through the hybrid tube 100, even while supplying less pressure to convey the fluid through the hybrid tube 100 and / or when drops in pressure are experienced due to the small diameter tubes, bends in the tubes, etc. In some embodiments, the inner diameter of the interior tube layer 110 may be less than 10 mm, less than 9 mm, less than 8 mm, less than 7 mm, less than 6 mm, less than 5 mm, less than 4 mm, less than 3 mm, less than 2 mm, or less than 1 mm. In some embodiments, the TPV composition used for the interior tube layer 110 provides an inner surface of the interior tube layer 110 that has a surface energy that is less than the surface energy of polytetrafluoroethylene (PTFE). In some embodiments, the TPV composition used for the interior tube layer 110 provides an inner surface of the interior tube layer 110 that has a surface energy that is less than the surface energy of uncured natural rubber, cured natural rubber, uncured synthetic rubber (e.g.,SBR, NBR, chloropene rubber, EPDM, etc.), or cured synthetic rubber.

[0026] Surface energy may generally be related to contact angle and therefore low surface energy TPVs suitable for use in the interior tube layer 110 can be selected based on selecting TPVs with low contact angles with respect to water or a water / glycol mixture. In some embodiments, the TPV composition suitable for use in the interior tube layer 110 is a TPV composition exhibiting a contact angle of greater than 90°, greater than 95°, greater than 100°, greater than 105°, greater than 110°, greater than 115°, greater than 120°, greater than 125°, greater than 130°, greater than 135°, greater than 140°, greater than 145°, greater than 150°, greater than 155°, greater than 160°, greater than 165°, greater than 170°, or greater than 175° with respect to water or a water / glycol mixture.

[0027] The TPV composition used for the interior tube layer 110 can be selected based on meeting any one or any combination of the previously described properties - permeation, metal oxide content, elongation to break, hardness, and low surface energy (including contact angle). In some embodiments, the TPV composition used for the interior tube layer 110 will meet only one of the previously described properties. In some embodiments, the TPV composition used for the interior tube layer 110 will meet more than one but less thanall of the previously described properties. In some embodiments, the TPV composition used for the interior tube layer 110 will meet all of the previously described properties.

[0028] A primary function of the outer tube layer 120 is to provide strength and resistance to environmental exposures in data center cooling applications. As such, the material of the outer tube layer 120 should generally be a material that possesses the desired strength and resistance to environmental exposures common to data center cooling applications, such as UV, ozone, and various other abrasives. In some embodiments, the material of the outer tube layer 120 is a thermoplastic vulcanizate (TPV). The composition of the TPV used for the outer tube layer 120 may be selected to provide the desired environmental resistance. In some embodiments, the composition of the TPV material used for the outer tube layer 120 is a different composition from the TPV composition used for the interior tube layer 110.

[0029] In some embodiments, the TPV composition used for the outer tube layer 120 is a TPV composition that meets the V-0 classification for UL 94, the Standard for Safety of Flammability of Plastic Materials for Parts in Devices and Appliances Testing (plastics flammability standard established by Underwriters Laboratories. The V-0 classification indicates that burning of a vertical specimen of the tested material stops within 10 seconds. Examples of commercially available TPV compositions that meet the UL 94 V-0 classification and which may therefore be suitable for use for the outer tube layer 120 of the hybrid tube 100 described herein include, but are not limited to, Santoprene® 251-90 and Santoprene® 253-40, manufactured by Celanese Corporation of Irving, TX, USA. Both Santoprene® 251 - 90 and Santoprene® 253-40 are provided in halogen free (HF) versions, and in some embodiments, the HF versions of these TPV compositions used as the TPV composition for the outer tube layer 120.

[0030] In some embodiments, the TPV composition used for the outer layer is a TPV composition having a relatively high hardness and is therefore characterized as having good strength. In some embodiments, the TPV composition suitable for use in the outer tube layer 120 has a hardness greater than 80A, such as greater than 90A. In some embodiments, the TPV composition suitable for use in the outer tube layer 120 has a hardness greater than 30D, such as greater than 40D.

[0031] Any suitable combination of interior tube layer material and outer tube layer material can be used, provided that the hybrid tube 100 provides some combination of chemical resistance, low surface energy inner surface layer, improved strength, high degree of flexibility, resistance to crimping and kinking, and resistance to environmental exposures such as UV and ozone. In some embodiments, the interior tube layer material is a first TPV material (i.e. , a TPV material with a first composition) while the outer tube layer material is a second TPV material (i.e., a TPV material with a second composition different from the first composition).

[0032] In some embodiments, the material of the interior tube layer 110 is free of metal, so as to avoid the possibility of metal material leaching into the material conveyed through the hybrid tube 100. In some embodiments, the material of the outer tube layer 120 is free of halogens, so as to avoid a situation where the outer tube layer 120 being exposed to fire results in the conversion of the halogen to an acid.

[0033] As described previously, the dimensions of the interior tube layer 110 and the outer tube layer 120 may be selected such that the outer tube layer 120 resides directly on / against the interior tube layer 110. In some embodiments, the outer tube layer 120 adheres to the interior tube layer 110 to provide for a structurally robust and cohesive hybrid tube 100. Any type of adhesion can be used for the interior tube layer 110 and outer tube layer 120, including multiple types of adhesion. In some embodiments, the outer tube layer 120 is adhered to the interior tube layer 110 via one or more of chemical bonding, intermolecular attraction, and mechanical adhesion. In some embodiments, the specific manner of adhesion may be due to the coextrusion processing used in the formation of hybrid tube 100.

[0034] In some embodiments where the outer tube layer 120 resides directly against the interior tube layer 110, no reinforcement layers or materials are located between the outer tube layer 120 and the interior tube layer 110. Such reinforcement layers are not necessary in the disclosed hybrid tube construction due to the selection of specific materials for the outer tube layer 120 and the interior tube layer 110. The material of the interior tube layer 110 is selected primarily to provide the desired chemical resistance and / or low surface energy, even if selecting material based on obtaining these properties provides an interiortube layer 110 with relatively low structural strength. The material of the outer tube layer 120 is selected to provide this strength, as well as protection against environmental exposure. Because the outer tube layer 120 provides the desired structure strength, reinforcement layers or material are generally not required.

[0035] When selecting the material for the outer tube layer 120, consideration is also given to providing an outer tube layer 120 that is bendable and not susceptible to crimping or kinking despite providing structural strength and resistance to environmental exposure. Some balancing may need to occur to select the appropriate material for outer tube layer 120. For example, some structural strength may be sacrificed to ensure the hybrid tube 100 remains sufficiently bendable. Adjusting the composition of the TPV material used for the outer tube layer 120 may allow for striking the desired balance between these properties and characteristics.

[0036] The hybrid tube 100 described herein is also preferably free of any cover layer formed over the outer tube layer 120. For example, many tubes or hoses use a braided cover layer over a composite tube construction to provide additional strength and / or environmental resistance. Such cover layers are not necessary for the hybrid tube construction described herein, as the material selected for the outer tube layer 120 sufficiently provides the desired structural strength and environmental resistance. Avoiding a cover layer in the hybrid tube construction may also help to ensure that the dimensions of the hybrid tube 100 remain minimal and that good bendability without crimping or kinking is retained. Thes attributes help to ensure that the hybrid tube 100 described herein is well suited for applications such as data center cooling systems, wherein small tubes with good bendability are desired.

[0037] While the hybrid tubes described herein have been explained primarily in the context of their application in data center cooling systems, it should be appreciated that the hybrid tubes described herein may have potential applications in industrial, food and beverage, hydraulic, chemical caustics, pneumatics, automotive, aerospace, and other fluid conveyance, or fluid power applications. The hybrid tubes can be formulated to carry a variety of materials including water, steam, caustic fluids, acidic fluids, solvents, flammable fluids, air, gases, and oil. The composition of the material used for the interior tube layermay be adjusted to provide chemical resistance to the material flowed through the tube. This may include varying the composition of the TPV used for the interior tube layer or using a non-TPV material.

[0038] EMBODIMENTS

[0039] Embodiment 1 : A hybrid tube for use in industrial and hydraulic hoses, comprising: an interior tube layer having a hollow passage extending therethrough, wherein the material of the interior tube layer is a first thermoplastic vulcanizate composition; and an outer tube layer formed on and coaxially aligned with the interior tube layer, wherein the material of the outer tube layer is a second thermoplastic vulcanizate composition; wherein the first thermoplastic vulcanizate composition is different from the second thermoplastic vulcanizate composition; and wherein the hybrid tube is free of a reinforcement layer or layers positioned between the interior tube layer and the outer tube layer.

[0040] Embodiment 2: The hybrid tube of Embodiment 1 , wherein the thickness of the outer tube layer is greater than the thickness of the interior tube layer.

[0041] Embodiment 3: The hybrid tube of any preceding Embodiment, wherein the interior tube layer is from about 10 to about 50% of the thickness of the hybrid tube and the outer tube layer is from about 50 to about 90% of the thickness of the hybrid tube.

[0042] Embodiment 4: The hybrid tube of any preceding Embodiment, wherein the interior tube layer is about 10% of the thickness of the hybrid tube.

[0043] Embodiment 5: The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition has surface energy equal to or less than the surface energy of polytetrafluoroethylene (PTFE).

[0044] Embodiment 6: The hybrid tube of any preceding Embodiment, wherein the interior diameter of the interior tube layer is less than 10 mm.

[0045] Embodiment 7: The hybrid tube of any preceding Embodiment, wherein the interior tube layer is adhered to the outer tube layer via one or more of chemical bonding, intermolecular attraction, and mechanical adhesion.

[0046] Embodiment 8: The hybrid tube of any preceding Embodiment, wherein the interior tube layer is adhered directly to the outer tube layer with no intermediate layer located between the interior tube layer and the outer tube layer.

[0047] Embodiment 9: The hybrid tube of any preceding Embodiment, wherein the hybrid tube is free of any reinforcement layers.

[0048] Embodiment 10: The hybrid tube of any preceding Embodiment, wherein the hybrid tube is free of any cover layers.

[0049] Embodiment 11 : The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a permeation of less than 1 g / m2 / day.

[0050] Embodiment 12: The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having an elongation to break of greater than 500%.

[0051] Embodiment 13: The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a hardness between 50A and 99A.

[0052] Embodiment 14: The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a metal oxide content less than 0.10 wt%.

[0053] Embodiment 15: The hybrid tube of any preceding Embodiment, wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a permeation of less than 1 g / m2 / day, an elongation to break of greater than 500%, a hardness between 50A and 99A, and a metal oxide content less than 0.10 wt%.

[0054] Embodiment 16: The hybrid tube of any preceding Embodiment, wherein the second thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition that meets the 94 UL V-0 classification.

[0055] Embodiment 17: The hybrid tube of any preceding Embodiment, wherein the second thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a hardness greater than 90A or greater than 30D.

[0056] From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the scope of the invention. Accordingly, the invention is not limited except as by the appended claims.

[0057] Although the technology has been described in language that is specific to certain structures and materials, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific structures and materials described. Rather, the specific aspects are described as forms of implementing the claimed invention. Because many embodiments of the invention can be practiced without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.

[0058] Unless otherwise indicated, all number or expressions, such as those expressing dimensions, physical characteristics, etc., used in the specification (other than the claims) are understood as modified in all instances by the term "approximately". At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the claims, each numerical parameter recited in the specification or claims which is modified by the term "approximately" should at least be construed in light of the number of recited significant digits and by applying rounding techniques. Moreover, all ranges disclosed herein are to be understood to encompass and provide support for claims that recite any and all sub-ranges or any and all individual values subsumed therein. For example, a stated range of 1 to 10 should be considered to include and provide support for claims that recite any and all sub-ranges or individual values that are between and / or inclusive of the minimum value of 1 and the maximum value of 10; that is, all sub-ranges beginning with a minimum value of 1 or more and ending with a maximum value of 10 or less (e.g., 5.5 to 10, 2.34 to 3.56, and so forth) or any values from 1 to 10 (e.g., 3, 5.8, 9.9994, and so forth).

Claims

CLAIMSI / We claim:1 . A hybrid tube for use in industrial and hydraulic hoses, comprising: an interior tube layer having a hollow passage extending therethrough, wherein the material of the interior tube layer is a first thermoplastic vulcanizate composition; and an outer tube layer formed on and coaxially aligned with the interior tube layer, wherein the material of the outer tube layer is a second thermoplastic vulcanizate composition; wherein the first thermoplastic vulcanizate composition is different from the second thermoplastic vulcanizate composition; and wherein the hybrid tube is free of a reinforcement layer or layers positioned between the interior tube layer and the outer tube layer.

2. The hybrid tube of claim 1 , wherein the thickness of the outer tube layer is greater than the thickness of the interior tube layer.

3. The hybrid tube of claim 1 , wherein the interior tube layer is from about 10 to about 50% of the thickness of the hybrid tube and the outer tube layer is from about 50 to about 90% of the thickness of the hybrid tube.

4. The hybrid tube of claim 1 , wherein the interior tube layer is about 10% of the thickness of the hybrid tube.

5. The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition has surface energy equal to or less than the surface energy of polytetrafluoroethylene (PTFE).

6. The hybrid tube of claim 1 , wherein the interior diameter of the interior tube layer is less than 10 mm.

7. The hybrid tube of claim 1 , wherein the interior tube layer is adhered to the outer tube layer via one or more of chemical bonding, intermolecular attraction, and mechanical adhesion.

8. The hybrid tube of claim 1 , wherein the interior tube layer is adhered directly to the outer tube layer with no intermediate layer located between the interior tube layer and the outer tube layer.

9. The hybrid tube of claim 1 , wherein the hybrid tube is free of any reinforcement layers.

10. The hybrid tube of claim 1 , wherein the hybrid tube is free of any cover layers.11 . The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a permeation of less than 1 g / m2 / day.

12. The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having an elongation to break of greater than 500%.

13. The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a hardness between 50A and 99A.

14. The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a metal oxide content less than 0.10 wt%.

15. The hybrid tube of claim 1 , wherein the first thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a permeation of less than 1 g / m2 / day,an elongation to break of greater than 500%, a hardness between 50A and 99A, and a metal oxide content less than 0.10 wt%.

16. The hybrid tube of claim 1 , wherein the second thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition that meets the 94 UL V-0 classification.

17. The hybrid tube of claim 1 , wherein the second thermoplastic vulcanizate composition is a thermoplastic vulcanizate composition having a hardness greater than 90A or greater than 30D.

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