Green fabrication of polytetrafluoroethylene and expanded polytetrafluoroethylene and uses thereof

Patent metadata

Field	Value
Publication number	US-2020231775-A1
Application number	US-202016744505-A
Country	US
Kind code	A1
Filing date	Jan 16, 2020
Priority date	Jan 22, 2019
Publication date	Jul 23, 2020
Grant date	—

Abstract

Green, fast and easy evaporating organic solvent for use as a lubricant in the processing of polytetrafluoroethylene (PTFE) and expanded polytetrafluoroethylene (ePTFE) products and processes of using the solvents to fabricate the products are disclosed herein. The products can be used in the field of bio- and medical applications, such as for use in vascular grafts, cardiovascular and soft tissue patches, facial implants, surgical sutures, and endovascular prosthesis, and for any products known in the aerospace, electronics, fabrics, filtration, industrial and sealant arts.

First claim

What is claimed is:

1 . A process for preparing an extruded product, the process comprising:
blending a polytetrafluoroethylene (PTFE) powder with a lower alkyl (C 1 -C 10 ) alcohol to form a blend; preforming the blend; extruding the preformed blend to form a product; and evaporating the lower alkyl (C 1 -C 10 ) alcohol from the extruded product.

2 . The process as set forth in claim 1 , wherein the lower alkyl (C 1 -C 10 ) alcohol is a biocompatible lower alkyl (C 1 -C 10 ) alcohol selected from the group consisting of methanol, ethanol, isopropanol, and combinations thereof.

3 . The process as set forth in claim 2 , wherein the biocompatible lower alkyl (C 1 -C 10 ) alcohol is ethanol.

4 . The process as set forth in claim 1 , wherein the lower alkyl (C 1 -C 10 ) alcohol is further mixed with water before blended with the PTFE powder and the alcohol/water mixture has a weight ratio of alcohol:water of from about 10:90 to about 100:0.

5 . The process as set forth in claim 1 , wherein the lower alkyl (C 1 -C 10 ) alcohol is present in the blend in an amount of from about 10% by weight to about 30% by weight.

6 . The process as set forth in claim 1 , wherein blending comprising rolling the PTFE powder and lower alkyl (C 1 -C 10 ) alcohol for a period of from about 30 minutes to about 120 minutes.

7 . The process as set forth in claim 6 further comprising aging the blend for a period of from about 30 minutes to about 48 hours after rolling.

8 . The process as set forth in claim 1 comprising preforming the blend at a pressure of from about 1 MPa to about 30 MPa.

9 . The process as set forth in claim 1 , wherein evaporating of the lower alkyl (C 1 -C 10 ) alcohol comprises heating the extruded product to a temperature of from 60° C. to about 200° C. for a period of from about 0.5 minutes to about 120 minutes.

10 . The process as set forth in claim 1 further comprising sintering the heated extruded product at a temperature of from about 360° C. to about 400° C. for a period of from about 10 seconds to about 10 minutes.

11 . The process as set forth in claim 1 further comprising expanding the extruded product.

12 . The process as set forth in claim 10 , wherein the expanding is conducted at a temperature of from about 25° C. to about 340° C.

13 . The process as set forth in claim 10 , wherein the extruded product is expanded at a rate of from about 1 mm/min to about 1000 mm/min.

14 . The process as set forth in claim 10 , wherein the extruded product is expanded at an expansion ratio of from about 100% to about 800%.

15 . The process as set forth in claim 4 further comprising dissolving a target material in the lower alkyl (C 1 -C 10 ) alcohol.

16 . A medical implant comprising the extruded product as set forth in claim 1 .

17 . The medical implant as set forth in claim 16 selected from the group consisting of vascular grafts, cardiovascular and soft tissue patches, facial implants, surgical sutures, and endovascular prostheses.

18 . A method of preparing an extruded product, the method comprising:
dissolving a target additive into an organic solvent to form a target-solvent solution; immersing a polytetrafluoroethylene (PTFE) powder in the target-solvent solution to form a blend; preforming the blend; extruding the preformed blend to form a product; and evaporating the target-solvent solution from the extruded product.

19 . The process as set forth in claim 18 , wherein the organic solvent is selected from the group consisting of a lower alkyl alcohols, acetic acid, ethyl acetate, acetonitrile, chloroform, benzene, methylbenzene, dimethylbenzene, acetone, 2-butanone, cyclopentanone, pentane, n-hexane, cyclohexane, heptane, dichloromethane, dichloroethane, trichloroethane, tetrachloromethane, tetrachloroethane, trimethylpentane, 1,4-dioxane, chloroform, ether, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), tetrahydrofuran (THF), and combinations thereof.

20 . The process as set forth in claim 18 , wherein the organic solvent is further mixed with a carrier before blended with the PTFE powder.

21 . The process as set forth in claim 18 , wherein the organic solvent is present in the blend in an amount of from about 10% by weight to about 30% by weight.

22 . The process as set forth in claim 18 , wherein blending comprising rolling the PTFE powder and organic solvent for a period of from about 30 minutes to about 120 minutes.

23 . The process as set forth in claim 22 further comprising aging the blend for a period of from about 30 minutes to about 48 hours after rolling.

24 . The process as set forth in claim 18 comprising preforming the blend at a pressure of from about 1 MPa to about 30 MPa.

25 . The process as set forth in claim 18 , wherein evaporating of the organic solvent comprises heating the extruded product to a temperature of from 60° C. to about 200° C. for a period of from about 0.5 minutes to about 120 minutes.

26 . The process as set forth in claim 18 further comprising expanding the extruded product.

27 . The process as set forth in claim 18 , wherein the target material is selected from the group consisting of a biofunctional material, a therapeutic, a natural compound, an aesthetic agent and combinations thereof.

28 . The process as set forth in claim 27 , wherein the biomolecule is a growth factor selected from the group consisting of epidermal growth factor (EGF), fibroblast growth factor (FGF), nerve growth factor (NGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), granulocyte-macrophage colony-stimulating factor (GMCSF), granulocyte-colony stimulating factor (GCSF), transforming growth factor (TGF), Erythropieitn, thyroperoxidase (TPO), bone morphogenetic proteins (BMP), hepatocyte growth factor (HGF), growth differentiation factors (GDF), Neurotrophins, melanocyte-specific factor (MSF), sarcoma growth factor (SGF), and combinations thereof.

29 . The process as set forth in claim 18 , wherein the target material is present in the organic solvent in an amount of from about 0.1% by weight to about 5% by weight.

30 . A method for preparing an extruded product, the method comprising:
dissolving a target additive into an organic solvent to form a target-solvent solution; immersing a sintered extruded polytetrafluoroethylene (PTFE) product in the target-solvent solution to form a wetted PTFE product; and evaporating the target-solvent solution from the extruded product.

31 . The process as set forth in claim 30 , wherein evaporating of the target-solvent solution comprises heating the extruded product to a temperature of from 60° C. to about 200° C. for a period of from about 0.5 minutes to about 120 minutes.

32 . The process as set forth in claim 30 , wherein the target material is selected from the group consisting of a biomaterial, a therapeutic, a natural compound, an aesthetic agent and combinations thereof.

33 . The process as set forth in claim 32 , wherein the biomolecule is a growth factor selected from the group consisting of epidermal growth factor (EGF), fibroblast growth factor (FGF), nerve growth factor (NGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor

Assignees

• Wisconsin Alumni Res Found

Inventors

• Turng Lih-Sheng
• Xu Yiyang
• Lin Yu-Jyun
• Wang dong-fang

Classifications

• A61L31/16

  Biologically active materials, e.g. therapeutic substances {(A61L31/047 takes precedence)} · CPC title

• A61L31/146

  Porous materials, e.g. foams or sponges · CPC title

• A61L31/048

  obtained by reactions only involving carbon-to-carbon unsaturated bonds (A61L31/041 takes precedence) · CPC title

• A61L27/56

  Porous materials, {e.g. foams or sponges} · CPC title

• A61L27/16

  obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title