WO1992009652A1 - Polymer products - Google Patents

Polymer products Download PDF

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Publication number
WO1992009652A1
WO1992009652A1 PCT/GB1991/002047 GB9102047W WO9209652A1 WO 1992009652 A1 WO1992009652 A1 WO 1992009652A1 GB 9102047 W GB9102047 W GB 9102047W WO 9209652 A1 WO9209652 A1 WO 9209652A1
Authority
WO
WIPO (PCT)
Prior art keywords
porosifier
solution
porosity
polymer
surfactant
Prior art date
Application number
PCT/GB1991/002047
Other languages
French (fr)
Inventor
David Charlesworth
Christopher John Underwood
Kerm Sin Chian
Original Assignee
Newtec V.P. Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Newtec V.P. Limited filed Critical Newtec V.P. Limited
Publication of WO1992009652A1 publication Critical patent/WO1992009652A1/en

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L27/00—Materials for grafts or prostheses or for coating grafts or prostheses
    • A61L27/50—Materials characterised by their function or physical properties, e.g. injectable or lubricating compositions, shape-memory materials, surface modified materials
    • A61L27/56—Porous materials, e.g. foams or sponges
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/04—Hollow or tubular parts of organs, e.g. bladders, tracheae, bronchi or bile ducts
    • A61F2/06—Blood vessels
    • A61F2/062—Apparatus for the production of blood vessels made from natural tissue or with layers of living cells
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/26—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a solid phase from a macromolecular composition or article, e.g. leaching out

Definitions

  • This invention relates to methods of making polymer products and to novel products made according to the methods.
  • porosity was introduced into porous polymer products by addition of small amounts of a porosifier to a solution comprising dissolved polymer, the porosifer being chosen to be substantially insoluble in said solution and easily removable from the polymer product.
  • pore size in a polymer has been dictated substantially by the particulate size and quantity of porosifier added thereto.
  • the present invention provides methods of producing porous polymer products by addition of a particulate permeability control substance to a dissolved polymer, the substance, paradoxically, not acting as a porosifier to any substantial degree.
  • a method for producing a specified permeable and porosity porous polymer product by precipitating polymer from a solution thereof which contains a porosifier under conditions in which the precipitate forms a solid which is made porous by dissolving the porosifier, and controlling the permeability by including in the solution a specific amount of permeability controlling substance other than said porosifier.
  • the invention further includes products made according to the aforementioned method.
  • the effect of the permeability controlling substance may be more pronounced on the surfaces of the product.
  • the permeability controlling substance may itself be particulate and insoluble in said solution and may comprise a surfactant.
  • the surfactant may be an anionic detergent.
  • the surfactant may be comprised within the class of alkoxy sulphites and may be an alkaline metal salt of dodecyl sulphate.
  • the surfactant may be sodium dodecyl sulphate.
  • the permeability controlling substance may comprise between 0.1 and 10 per cent by weight of the solution.
  • the porosifier may be insoluble in said solution but soluble in aqueous systems.
  • the porosifier may comprise a carbonate such as, for example, sodium hydrogen carbonate.
  • the porosifier may have an average particle size of 50 to 100 microns and may comprise between 10 and 60 per cent by weight of the solution.
  • the polymer may comprise between 17 and 30 per cent by weight of said solution.
  • Figure 1 shows a method of producing a permeable and porous polymer product according to the invention
  • Figure 2 shows a perspective cut-away sectional view of a first form of polymer product which might, for example, be a wall of a vascular prosthesis;
  • Figure 3 shows a perspective cut-away sectional view of a second form of polymer product which might, as above, be a wall of a vascular prosthesis;
  • Figure 1 shows a specified porosity and permeable porous polymer product 10 being extruded from a polymer solution 11 which contains a porosifier 12 over a mandrel 13 which contacts a polymer precipitant 14, the polymer coating the mandrel 13 consequentially forming a solid.
  • the mandrel 13 may be driven by a motor 21 so as to move from left to right as illustrated through an extrusion head 20 to which the solution 11 is supplied by a pump 22.
  • the mandrel may be rotated about its axis to maintain the deposited coating at uniform thickness.
  • the permeability of the product 10 is controlled by the inclusion in the polymer solution 11 of a specific amount of permeability controlling substance 17.
  • the product 10 is stripped off the mandrel 13 and the porosifier 12 comprised therein is dissolved by washing therethrough an appropriate quantity of liquid in which the porosifier is soluble, which may, as shown in Figure 1, be the aforementioned precipitant 14.
  • the permeability control substance 17 is likewise removed from the product 10.
  • FIGS 2 and 2 show perspective cut-away sectional views of walls of vascular protheses made according to the invention.
  • the wall generally shown at 23 comprises pores 25 produced by dissolution of added porosifier 12 and smaller pores 37 formed as a consequence of the action of said permeability control substance 17.
  • the prosthesis of Figure 2 has been extruded from a polymer solution comprising a relatively large amount of permeability control substance 17.
  • the prosthesis of Figure 3 has been extruded from a polymer solution comprising a relatively small amount of permeability control substance 17.
  • the amount of permeability control substance 17 added to the extrudate is varied by adjusting the valve 15.
  • Figure 1 only illustrates the method according to the invention and that in practice a more sophisticated system of adding substance 17 to the extrudate may be employed.
  • the permeability controlling substance 17, in this case a surfactant, is particulate and insoluble in the polymer solution.
  • the surfactant is an anionic detergent comprised within the class of alkoxy sulphites and can be, for example, an alkaline metal salt of dodecyl sulphate, such as sodium dodecyl sulphate.
  • the surfactant comprises between 0.1 and 10 per cent by weight of- the solution, a typical value is 2 per cent.
  • the porosifier is insoluble in said solution but soluble in aqueous systems, and is a carbonate, such as, for example, sodium hydrogen carbonate.
  • the porosifier has an average particle size of 50 to 100 microns and comprises between 10 and 60 per cent by weight of the solution.
  • the polymer typically comprises 17 to 30 per cent by weight of said solution.

Abstract

A specified porosity porous polymer product is made by precipitating polymer from a solution which contains a suspended porosifier under conditions in which the precipitate forms a solid which is rendered porous by dissolving the porosifier, and controlling the porosity by including in the solution a specific amount of a porosity controlling substance other than said porosifier. The substance may be a surfactant. The polymer product is useful as a vascular prosthesis.

Description

POLYMER PRODUCTS
This invention relates to methods of making polymer products and to novel products made according to the methods.
Previously, porosity was introduced into porous polymer products by addition of small amounts of a porosifier to a solution comprising dissolved polymer, the porosifer being chosen to be substantially insoluble in said solution and easily removable from the polymer product.
Addition of the porosifier to the solvent in which the polymer is dissolved increases the number and size of pores present in the product. Appropriately sized pores in a polymer product are very desirable when the product takes the form of a vascular prosthesis, for example. Endothelial cells, amongst others, can colonise the prosthesis and provide a non-thrombogenic autogenous cell lining thereto.
Previously, pore size in a polymer has been dictated substantially by the particulate size and quantity of porosifier added thereto.
The present invention provides methods of producing porous polymer products by addition of a particulate permeability control substance to a dissolved polymer, the substance, paradoxically, not acting as a porosifier to any substantial degree.
According to the present invention there is provided a method for producing a specified permeable and porosity porous polymer product by precipitating polymer from a solution thereof which contains a porosifier under conditions in which the precipitate forms a solid which is made porous by dissolving the porosifier, and controlling the permeability by including in the solution a specific amount of permeability controlling substance other than said porosifier.
The invention further includes products made according to the aforementioned method.
The effect of the permeability controlling substance may be more pronounced on the surfaces of the product.
The permeability controlling substance may itself be particulate and insoluble in said solution and may comprise a surfactant.
The surfactant may be an anionic detergent. The surfactant may be comprised within the class of alkoxy sulphites and may be an alkaline metal salt of dodecyl sulphate.
The surfactant may be sodium dodecyl sulphate.
The permeability controlling substance may comprise between 0.1 and 10 per cent by weight of the solution.
The porosifier may be insoluble in said solution but soluble in aqueous systems.
The porosifier may comprise a carbonate such as, for example, sodium hydrogen carbonate.
The porosifier may have an average particle size of 50 to 100 microns and may comprise between 10 and 60 per cent by weight of the solution.
The polymer may comprise between 17 and 30 per cent by weight of said solution.
The invention will be further apparent from the following description and the several figures of the accompanying drawings, which illustrate, by way of example only, a method of producing polymer products according to the invention, and products formed according to the method.
Of the figures :-
Figure 1 shows a method of producing a permeable and porous polymer product according to the invention;
Figure 2 shows a perspective cut-away sectional view of a first form of polymer product which might, for example, be a wall of a vascular prosthesis;
and Figure 3 shows a perspective cut-away sectional view of a second form of polymer product which might, as above, be a wall of a vascular prosthesis;
Figure 1 shows a specified porosity and permeable porous polymer product 10 being extruded from a polymer solution 11 which contains a porosifier 12 over a mandrel 13 which contacts a polymer precipitant 14, the polymer coating the mandrel 13 consequentially forming a solid. The mandrel 13 may be driven by a motor 21 so as to move from left to right as illustrated through an extrusion head 20 to which the solution 11 is supplied by a pump 22. The mandrel may be rotated about its axis to maintain the deposited coating at uniform thickness. The permeability of the product 10 is controlled by the inclusion in the polymer solution 11 of a specific amount of permeability controlling substance 17.
The product 10 is stripped off the mandrel 13 and the porosifier 12 comprised therein is dissolved by washing therethrough an appropriate quantity of liquid in which the porosifier is soluble, which may, as shown in Figure 1, be the aforementioned precipitant 14. The permeability control substance 17 is likewise removed from the product 10.
Figures 2 and 2 show perspective cut-away sectional views of walls of vascular protheses made according to the invention. The wall generally shown at 23 comprises pores 25 produced by dissolution of added porosifier 12 and smaller pores 37 formed as a consequence of the action of said permeability control substance 17.
The prosthesis of Figure 2 has been extruded from a polymer solution comprising a relatively large amount of permeability control substance 17. The prosthesis of Figure 3 has been extruded from a polymer solution comprising a relatively small amount of permeability control substance 17.
Thus, as can be seen, where the pores 37 are relatively large and numerous in the prosthesis wall 23, a relatively small quantity of• permeability controlling substance 17 has been added to the polymer solution. Conversely, where said pores 37 are relatively small and few in number, a relatively large quantity of said permeability controlling substance 17 has been added to said polymer solution.
As shown in Figure 1, the amount of permeability control substance 17 added to the extrudate is varied by adjusting the valve 15.
It will be appreciated, however, that Figure 1 only illustrates the method according to the invention and that in practice a more sophisticated system of adding substance 17 to the extrudate may be employed.
The permeability controlling substance 17, in this case a surfactant, is particulate and insoluble in the polymer solution. The surfactant is an anionic detergent comprised within the class of alkoxy sulphites and can be, for example, an alkaline metal salt of dodecyl sulphate, such as sodium dodecyl sulphate.
Although the surfactant comprises between 0.1 and 10 per cent by weight of- the solution, a typical value is 2 per cent.
The porosifier is insoluble in said solution but soluble in aqueous systems, and is a carbonate, such as, for example, sodium hydrogen carbonate.
The porosifier has an average particle size of 50 to 100 microns and comprises between 10 and 60 per cent by weight of the solution.
The polymer typically comprises 17 to 30 per cent by weight of said solution.
Although the present invention has been described in conjunction with particular embodiments, viz vascular protheses, it will be appreciated by those skilled in the art that various other changes, omissions and additions thereto may be made without departing from the scope as described herein. For example, the methods according to the invention may be used in the production of porous products for use as filters and selectively permeable membranes.

Claims

1. A method for producing a specified porosity porous polymer product by precipitating polymer from a solution thereof which contains a porosifier under conditions in which the precipitate forms a solid which is made porous by dissolving the porosifier, and controlling the porosity by including in the solution a specific amount of a porosity controlling substance other than said porosifier.
2. A method for producing a porous polymer product comprising therein a porosity variation by precipitating polymer from a solution thereof which contains a porosifier under conditions in which the precipitate forms a solid which is made porous by dissolving the porosifier, and varying the porosity thereof by varying the amount of a porosity controlling substance included in the solution, said substance being other than said porosifier.
3. A method according to claim 2, in which the porosity controlling substance is a porosifier.
4. A method according to any one of claims 1 to 3, in which the porosity controlling substance comprises a surfactant.
5. A method according to claim 4, in which the surfactant is an anionic detergent.
6. A method according to claim 5, in which the anionic detergent is an alkoxy sulphite.
7. A method according to claim 4, in which the surfactant is an alkaline metal salt of dodecyl sulphate.
8. A method according to claim 4, in which the surfactant is sodium dodecyl sulphate.
9. A method according to claim 1, in which the porosity controlling substance comprises between 0.1 and 10 per cent by weight of the solution.
10. A method according to claim 1, in which the porosifier is insoluble in said solution.
11. A method according to claim 10, in which the porosifier is soluble in aqueous systems.
12. A method according to claim 10 or claim 11, in which the porosifier comprises a carbonate.
13. A method according to any one of claims 10 to 12, in which the porosifier is sodium hydrogen carbonate.
14. A method according to any one of claims 10 to
13, in which the porosifer has an average particle size of 50 to 100 microns.
15. A method according to any one of claims 10 to
14, in which the porosifer comprises between 10 and 60 per cent by weight of the solution.
16. A method according to claim 1, in which the polymer comprises between 17 and 30 per cent by weight of the said solution.
17. A polymer product made by a method according to any one of claims 1 to 16.
18. A polymer product according to claim 17, comprising a vascular prosthesis.
PCT/GB1991/002047 1990-11-22 1991-11-19 Polymer products WO1992009652A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9025382.4 1990-11-22
GB9025382A GB9025382D0 (en) 1990-11-22 1990-11-22 Polymer products

Publications (1)

Publication Number Publication Date
WO1992009652A1 true WO1992009652A1 (en) 1992-06-11

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Application Number Title Priority Date Filing Date
PCT/GB1991/002047 WO1992009652A1 (en) 1990-11-22 1991-11-19 Polymer products

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AU (1) AU8917691A (en)
GB (1) GB9025382D0 (en)
WO (1) WO1992009652A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001005333A1 (en) * 1999-07-20 2001-01-25 Medtronic, Inc. Foam-type vascular prosthesis with well-defined angio-permissive open porosity
US7727274B2 (en) 1998-11-23 2010-06-01 Medtronic, Inc. Porous synthetic vascular grafts with oriented ingrowth channels

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2092894A (en) * 1981-02-13 1982-08-25 Thoratec Lab Corp Arterial graft prosthesis
EP0286220A1 (en) * 1987-04-09 1988-10-12 Newtec Vascular Products Ltd. Methods and apparatus for making polymer material
WO1991005522A1 (en) * 1989-10-18 1991-05-02 Newtec V.P. Limited Polymer products

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2092894A (en) * 1981-02-13 1982-08-25 Thoratec Lab Corp Arterial graft prosthesis
EP0286220A1 (en) * 1987-04-09 1988-10-12 Newtec Vascular Products Ltd. Methods and apparatus for making polymer material
WO1991005522A1 (en) * 1989-10-18 1991-05-02 Newtec V.P. Limited Polymer products

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
WORLD PATENTS INDEX Week 7203, Derwent Publications Ltd., London, GB; AN 72-04804T & JP,B,47 001 173 (FUNAHASHI T.) March 1972 see abstract *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7727274B2 (en) 1998-11-23 2010-06-01 Medtronic, Inc. Porous synthetic vascular grafts with oriented ingrowth channels
US8187319B2 (en) 1998-11-23 2012-05-29 Medtronic, Inc. Porous synthetic vascular grafts with oriented ingrowth channels
WO2001005333A1 (en) * 1999-07-20 2001-01-25 Medtronic, Inc. Foam-type vascular prosthesis with well-defined angio-permissive open porosity
US6616699B2 (en) 1999-07-20 2003-09-09 Peter Paul Zilla Foam-type vascular prosthesis with well-defined angio-permissive open porosity
US6702848B1 (en) 1999-07-20 2004-03-09 Peter Paul Zilla Foam-type vascular prosthesis with well-defined anclio-permissive open porosity
US7632306B2 (en) 1999-07-20 2009-12-15 Medtronic, Inc. Foam-type vascular prosthesis with well-defined angio-permissive open porosity

Also Published As

Publication number Publication date
AU8917691A (en) 1992-06-25
GB9025382D0 (en) 1991-01-09

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