Multi-layer tube and process of making the same

Patent metadata

Field	Value
Publication number	US-10576679-B2
Application number	US-201715832828-A
Country	US
Kind code	B2
Filing date	Dec 6, 2017
Priority date	Aug 30, 2013
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

A vessel is configured to hold a product in an interior region formed in the vessel. The vessel includes an inner layer arranged to define the interior region and an outer layer. The vessel is formed using a blow-molding process in which a multiple layer parison is blow molded to form the vessel. The multiple layer parison is formed in an extrusion process in which a number of extruders are arranged to co-extrude associated inner and outer parisons to establish the multiple layer parison.

First claim

The invention claimed is:

1. A method of producing a multiple layer tube, the method comprising the steps of
extruding an inner-layer formulation to form an inner parison,
extruding a core-layer formulation to form a core parison,
extruding an outer-layer formulation to form an outer parison,
aligning the inner parison, the core parison, and the outer parison to cause the core parison to be located between the inner parison and the outer parison to cause the core parison to surround the inner parison and to be surrounded by the outer parison to form an extruded multiple layer tube,
wherein the multiple layer tube has a density of about 0.3 g/cm 3 to 0.8 g/cm 3 ,
wherein the core-layer formulation comprises one or more high density polyethylene base resins (HDPE), and
wherein the core-layer formulation comprises a chemical nucleating agent, a physical nucleating agent, and a physical blowing agent.

2. The method of claim 1 , wherein the multiple layer tube has a density of about 0.4 g/cm 3 and the core parison has a density less than a density of the inner parison.

3. The method of claim 1 , wherein the core parison has a density of about 0.1 g/cm 3 to 0.8 g/cm 3 .

4. The method of claim 3 , wherein the core parison has a density of about 0.3 g/cm 3 to 0.35 g/cm 3 .

5. The method of claim 4 , wherein the core parison has a density of about 0.32 g/cm 3 .

6. The method of claim 5 , wherein the core parison has a density less than a density of the outer parison.

7. The method of claim 6 , wherein the density of the inner parison is about equal to the density of the outer parison.

8. The method of claim 1 , wherein the multiple layer tube has a density of about 0.4 g/cm 3 and the core parison has a density less than a density of the outer parison.

9. The method of claim 1 , wherein the inner-layer formulation is different from the outer-layer formulation.

10. The method of claim 1 , wherein the inner-layer formulation is the same as the outer-layer formulation.

11. The method of claim 1 , wherein the core-layer formulation comprises an insulative cellular non-aromatic polymeric material.

12. The method of claim 11 , wherein the core-layer formulation comprises one or more high density polyethylene base resins (HDPE).

13. The method of claim 12 , wherein the HDPE is unimodal.

14. The method of claim 13 , wherein the unimodal HDPE is a unimodal, high-melt strength HDPE.

15. The method of claim 14 , wherein the unimodal, high-melt strength HDPE is electron beam modified.

16. The method of claim 15 , wherein the electron beam modified unimodal, high-melt strength HDPE has long chain branching and a melt index of about 0.25 g/10 min.

17. The method of claim 16 , wherein the core-layer formulation lacks talc.

18. The method of claim 17 , wherein the core-layer formulation further comprises a slip agent.

19. A method of producing a multiple layer tube, the method comprising the steps of
extruding an inner-layer formulation to form an inner parison,
extruding a core-layer formulation to form a core parison,
aligning the inner parison and the core parison to cause the core parison the core parison to surround the inner parison and form an extruded multiple layer tube,
wherein the multiple layer tube has a density of about 0.3 g/cm 3 to 0.8 g/cm 3 ,
wherein the core-layer formulation comprises one or more high density polyethylene base resins (HDPE), and
wherein the core-layer formulation comprises a chemical nucleating agent, a physical nucleating agent, and a physical blowing agent.

20. A method of producing a multiple layer tube, the method comprising the steps of
extruding a core-layer formulation to form a core parison,
extruding an outer-layer formulation to form an outer parison,
aligning the core parison and the outer parison to cause the core parison to be surrounded by the outer parison to form an extruded multiple layer tube,
wherein the multiple layer tube has a density of about 0.3 g/cm 3 to 0.8 g/cm 3 ,
wherein the core-layer formulation comprises one or more high density polyethylene base resins (HDPE), and
wherein the core-layer formulation comprises a chemical nucleating agent, a physical nucleating agent, and a physical blowing agent.

Assignees

• Berry Plastics Corp

Inventors

• Sun David Dezhou
• Driskill Philip A
• Minnette Jeffrey C
• Surti Birju A
• Williams Jonathan K

Classifications

• B29C2049/627

  using vacuum means · CPC title

• B29C49/4252

  Auxiliary operations prior to the blow-moulding operation not otherwise provided for · CPC title

• B29C2049/4608

  Nitrogen · CPC title

• B29C49/4817

  with means for closing off parison ends · CPC title

• B29C48/09

  Articles with cross-sections having partially or fully enclosed cavities, e.g. pipes or channels · CPC title