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CN-122014931-A - Tube and method for producing the same

CN122014931ACN 122014931 ACN122014931 ACN 122014931ACN-122014931-A

Abstract

The present invention relates to a tube having different compositions and properties along its length, and a method of making such a tube. The tube comprises a polymer resin, an elastomer, and optional components, and is formed by continuous extrusion using multiple feeders. The tube includes a first region comprising 70-100wt% of a first composition of a polymeric resin, 0-30wt% of an elastomer, and 0-10wt% of an optional component, and a second region at least 30 times the length of the second region from the first region and comprising 0-50wt% of a second composition of a polymeric resin, 50-100wt% of an elastomer, and 0-10wt% of an optional component. The polymer resin and elastomer concentrations continuously vary between the regions to produce a compositionally graded structure having at least 10% hardness, tensile strength, elasticity, or color differences between the first region and the second region.

Inventors

  • L. Balzano

Assignees

  • 科腾聚合物荷兰有限责任公司

Dates

Publication Date
20260512
Application Date
20251111
Priority Date
20241112

Claims (15)

  1. 1. A tube having an Outer Diameter (OD), the tube comprising along its length: A first region comprising a first composition having a defined concentration of components comprising a) 70-100wt% of a first polymer resin, b) 0-30wt% of a first elastomer, and c) 0-10wt% of optional components; A second region comprising a second composition having a defined concentration of components comprising a) 0-50wt% of a second polymer resin that is the same as or different from the first polymer resin, b) 50-100wt% of a second elastomer that is the same as or different from the first elastomer, and c) 0-10wt% of an optional component that is the same as or different from the optional component in the first composition; Wherein the concentrations of the polymer resin and the elastomer component vary continuously longitudinally along the length of the tube between the first region and the second region to form a compositionally graded structure, wherein at least one physical property selected from the group consisting of hardness, tensile strength, elongation at break, and flexural modulus differs by at least 10%, 20%, or 30% between the first region and the second region, wherein hardness is determined according to ASTM D2240, tensile strength is determined according to ASTM D638, elongation at break is determined according to ASTM D412, flexural modulus is determined according to ASTM D790; wherein the tube has an aspect ratio L/OD of about 5-1500; wherein the polymeric resin is selected from the group consisting of fluoropolymers, polyolefins, polyurethanes, styrenic polymers, polyesters, polyamides, vinyl polymers, polycarbonates, and mixtures thereof, and Wherein the elastomer is selected from the group consisting of styrenic thermoplastic elastomers, styrenic thermoplastic olefins, polyolefin elastomers, ethylene propylene rubbers, thermoplastic polyurethanes, and mixtures thereof, and Wherein the polymeric resin and the elastomer differ by at least 20%, 25% or 30% in at least one of shore a hardness, shore D hardness and flexural modulus.
  2. 2. The tube of claim 1, wherein the tube is obtained by continuous extrusion, wherein at least two feeders positioned along the extruder barrel are optionally used to vary the relative proportions of the polymer resin and elastomer along the length of the tube.
  3. 3. The tube of claim 1, wherein the elastomer is a styrene-based thermoplastic elastomer selected from the group consisting of unhydrogenated styrenic block copolymers and hydrogenated styrenic block copolymers.
  4. 4. The tube of claim 1, wherein the polymer resin is a polyolefin.
  5. 5. The tube of any one of claims 1-4, wherein the tube is obtained by continuous extrusion in an extruder, wherein the concentration of the polymer resin and elastomer continuously varies along the extrusion direction to form a longitudinal composition gradient without co-extruding separate streams.
  6. 6. The tube of any one of claims 1-4, wherein the tube exhibits a hardness variation of at least 10%, 20%, or 30% between the first region and the second region, and wherein the hardness varies continuously along a longitudinal direction of the tube corresponding to the extrusion direction over at least 30%, 40%, or 50% of the total tube length.
  7. 7. The tube of any one of claims 1-4, wherein the tube exhibits a longitudinal hardness gradient from a shore D hardness of 60-90 in the first region to a shore a hardness of 15-50 in the second region.
  8. 8. The tube of any one of claims 1-4, wherein the total length of the tube is 4 inches to 8.2 feet (0.1-2.5 m), corresponding to an aspect ratio L/OD of 5-700.
  9. 9. The tube according to any one of claims 1-4, wherein the tube is obtained by gradually varying the feed rate of the elastomer relative to the polymer resin over time during continuous extrusion by means of separate main and secondary feeders positioned at different barrel sections of the extruder, thereby forming a longitudinal property gradient in the extrusion direction without connecting separate tube sections.
  10. 10. The tube of claim 3, wherein the styrene-based thermoplastic elastomer is a hydrogenated styrenic block copolymer ：S-E/B-S、(S-E/B)nX、(S-E/B-S)nX、S-EP-S、（S-EP）nX、(S-EP-S)nX、S-E/B/S-S、（S-E/B/S-S）nX、(S-E/B/S)nX、S-EP/S-S、（S-EP/S-S）nX、（S-EP/S）nX、 having a general structure selected from the group consisting of, and mixtures thereof, wherein each block S is a polymer block composed of vinyl aromatic units, each block E/B is a polymer block composed of ethylene (E) units and butene (B) units, each block EP is a polymer block composed of ethylene-propylene (EP) units, each block E/B/S is a polymer block composed of ethylene (E) units/butene (B) units and vinyl aromatic (S) units, each block EP/S is a polymer block composed of ethylene-propylene (EP) units and vinyl aromatic (S) units, n is an integer from 2 to 30, and X is the residue of a coupling agent.
  11. 11. The tube of any one of claims 1-4, wherein a tube length from the first region to the second region exhibits at least one of the following longitudinal performance gradients: (a) The hardness decreases from a shore D of about 60-90 in the first region to a shore a of about 15-50 in the second region, (B) The tensile strength decreases from about 25-120 MPa in the first region to about 2-30 MPa in the second region, (C) The flexural modulus decreases from about 1000 to 5000 MPa in the first region to about 1 to 100 MPa in the second region, and (D) The elongation at break increases from about 50-200% in the first region to about 150-1000% in the second region.
  12. 12. A method of making a tube having an Outer Diameter (OD), comprising: Feeding a first composition having a defined concentration of components to a first feeder of an extruder, wherein the components include a polymer resin, an elastomer, and optional components; feeding a second composition having a defined concentration of components including a polymer resin, an elastomer, and optional components to a second feeder located downstream along the extruder barrel; optionally, feeding one or more optional components to the first feeder, the second feeder, or both; Controlling the relative feed rates of the first and second compositions during continuous extrusion to continuously vary the concentrations of the polymer resin and elastomer components longitudinally in the extrusion direction to form a compositionally graded melt, and Extruding the compositionally graded melt through a die to produce a tube, wherein at least one physical property selected from hardness, tensile strength, elongation at break, and flexural modulus between the first region and the second region differs by at least 10%, 20%, or 30%, wherein hardness is determined according to ASTM D2240, tensile strength is determined according to ASTM D638, elongation at break is determined according to ASTM D412, flexural modulus is determined according to ASTM D790, and Wherein the first composition comprises 70 to 100wt% of the first polymer resin, 0 to 30wt% of the first elastomer, and 0 to 10wt% of optional components; Wherein the second composition comprises 0 to 50wt% of a second polymer resin that is the same as or different from the first polymer resin, 50 to 100wt% of a second elastomer that is the same as or different from the first elastomer, and 0 to 10wt% of an optional component that is the same as or different from the optional component in the first composition, each based on the total weight of the respective composition; wherein the polymeric resin is selected from the group consisting of fluoropolymers, polyolefins, polyurethanes, styrenic polymers, polyesters, polyamides, vinyl polymers, polycarbonates, and mixtures thereof; Wherein the elastomer is selected from the group consisting of styrene-based thermoplastic elastomers, styrene-based thermoplastic olefins, polyolefin elastomers, ethylene propylene rubbers, thermoplastic polyurethanes, and mixtures thereof, and Wherein the polymeric resin and the elastomer differ by at least 20%, 25% or 30% in at least one of shore a hardness, shore D hardness and flexural modulus.
  13. 13. The method of claim 12, wherein the polymer resin is a polyolefin and the elastomer is a styrene-based thermoplastic elastomer selected from unhydrogenated or hydrogenated styrenic block copolymers.
  14. 14. The method of any of claims 12-13, wherein the composition gradient is established by gradually varying the feed rate of the elastomer relative to the polymer resin over time in a single extruder, thereby forming a longitudinal and continuous composition gradient in the extrusion direction, rather than co-extruding separate material streams into a die.
  15. 15. The method according to any one of claims 12-13, wherein the obtained tube exhibits a hardness variation of at least 10%, 20% or 30% between the first and second regions, and wherein the hardness varies continuously along the longitudinal extrusion direction.

Description

Tube and method for producing the same Technical Field The present invention relates to a tube prepared by extrusion and a method of preparing the same, wherein the tube has a gradient of properties (e.g., hardness, tensile strength, elasticity or color strength, etc.) along the length of the tube. Background Polymeric and elastomeric tubes are widely used in many industries including medical, industrial, automotive and consumer applications. These tubes typically exhibit different mechanical or physical properties along their length, such as different hardness, elasticity, toughness, or color, to meet the specific functional requirements of each segment of the tube. For example, in medical catheters, certain portions of the tube may need to be softer and more flexible in order to provide comfort to the patient near the insertion site, while other portions need to be more rigid in order to achieve control, stability, or torque transfer. Also, in industrial or automotive pipelines, performance gradients may enhance vibration damping, provide flexibility near the coupling, or increase wear or chemical resistance in high stress areas. Conventional techniques for producing tubing having different properties along its length typically involve joining or welding tube sections made of different materials. While these processes effectively create discrete zones of hardness, they add to the complexity of the preparation and may introduce weak joints or discontinuities. Other methods such as localized heating or cooling can alter crystallinity and hardness, but are difficult to control and create inconsistent gradients. Coextrusion techniques, which simultaneously extrude multiple materials through concentric dies, are also used to create radial or layered gradients, but require complex machinery, precise synchronization of multiple material flows, and are limited to polymer pairs exhibiting interfacial compatibility. There remains a need for a simpler, more versatile process that can form both longitudinal (axial) and continuously graded tubing without relying on conventional coextrusion or welding techniques. Summary of The Invention In one aspect, a tube having different compositions and physical properties along its length, and a method of making such a tube, are disclosed. The tube includes at least a polymer resin and an elastomer whose concentration varies continuously along the tube. The tube includes a first region comprising a first composition having a defined concentration of components, wherein the defined concentration of components comprises 70-100wt% polymer resin, 0-30wt% elastomer, and 0-10wt% optional components, and a second region comprising a second composition having a defined concentration of components, wherein the defined concentration of components comprises 0-50wt% polymer resin, 50-100wt% elastomer, and 0-10wt% optional components. The concentrations of the polymer resin and the elastomer component vary continuously longitudinally along the length of the tube between the first region and the second region to form a compositionally graded structure, wherein at least one physical property selected from the group consisting of hardness, tensile strength, elongation at break, and flexural modulus differs by at least 10%, 20%, or 30% between the first region and the second region, wherein hardness is determined according to ASTM D2240, flexural modulus is determined according to ASTM D790, tensile strength is determined according to ASTM D638, and elongation at break is determined according to ASTM D412. The length to diameter ratio (L/OD) of the tube is about 5-1500. The polymeric resin is selected from the group consisting of fluoropolymers, polyolefins, polyurethanes, styrenic polymers, polyesters, polyamides, vinyl polymers, polycarbonates, and mixtures thereof. The elastomer is selected from the group consisting of styrenic thermoplastic elastomers, styrenic thermoplastic olefins, polyolefin elastomers, ethylene propylene rubber, thermoplastic polyurethanes, and mixtures thereof. The polymeric resin and elastomer differ by at least 20%, 25%, or 30% in at least one of shore a hardness, shore D hardness, and flexural modulus, wherein hardness is determined according to ASTM D2240, flexural modulus is determined according to ASTM D790. In one aspect, a method of making a tube having an Outer Diameter (OD) is disclosed. The method includes feeding a first composition having a defined concentration of components to a first feeder of an extruder, wherein the components include a polymer resin, an elastomer, and an optional component, feeding a second composition having a defined concentration of components to a second feeder located downstream along a barrel of the extruder, wherein the components include a polymer resin, an elastomer, and an optional component, optionally feeding one or more optional components to the main feeder, the secondary feeder, or both, controlling the relative feed ra