CA2254725A1 - Composite device and method of making a composite device - Google Patents
Composite device and method of making a composite device Download PDFInfo
- Publication number
- CA2254725A1 CA2254725A1 CA002254725A CA2254725A CA2254725A1 CA 2254725 A1 CA2254725 A1 CA 2254725A1 CA 002254725 A CA002254725 A CA 002254725A CA 2254725 A CA2254725 A CA 2254725A CA 2254725 A1 CA2254725 A1 CA 2254725A1
- Authority
- CA
- Canada
- Prior art keywords
- strips
- resin
- mandrel
- pipe
- organic material
- Prior art date
- Legal status (The legal status 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 status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/30—Shaping by lay-up, i.e. applying fibres, tape or broadsheet on a mould, former or core; Shaping by spray-up, i.e. spraying of fibres on a mould, former or core
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C70/00—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts
- B29C70/04—Shaping composites, i.e. plastics material comprising reinforcements, fillers or preformed parts, e.g. inserts comprising reinforcements only, e.g. self-reinforcing plastics
- B29C70/28—Shaping operations therefor
- B29C70/54—Component parts, details or accessories; Auxiliary operations, e.g. feeding or storage of prepregs or SMC after impregnation or during ageing
- B29C70/546—Measures for feeding or distributing the matrix material in the reinforcing structure
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Composite Materials (AREA)
- Mechanical Engineering (AREA)
- Reinforced Plastic Materials (AREA)
- Laminated Bodies (AREA)
Abstract
A method of making a pipe is provided in which a strip of surface treated polypropylene is soaked in phenolic resin, wrapped around a pipe and cured.
The pipe may be treated with a release agent, in which case the pipe may be removed after the resin is cured to form a stand alone pipe. The pipe may be moved while the resin is cured, and further strips applied to the pipe to make continuous pipe. A polymeric film may be used to contain the strip while it is curing. The method may be applied to a tank form to make a tank in like manner. Other examples of end products include;
concrete reinforcement (overlay), circuit boards, wear pads, and shaped components.
The pipe may be treated with a release agent, in which case the pipe may be removed after the resin is cured to form a stand alone pipe. The pipe may be moved while the resin is cured, and further strips applied to the pipe to make continuous pipe. A polymeric film may be used to contain the strip while it is curing. The method may be applied to a tank form to make a tank in like manner. Other examples of end products include;
concrete reinforcement (overlay), circuit boards, wear pads, and shaped components.
Description
TITLE OF THE INVENTION
Composite Device and Method of Making a Composite Device NAME OF INVENTOR
Anthony G. Warren Steuart Scott FIELD OF THE INVENTION
This invention relates to methods of making composite devices, and composite 1o devices made by such methods.
BACKGROUND OF THE INVENTION
Creating protective coatings for pipes, or making pipes or other devices from composite materials, is complicated by the difficulty of obtaining a material that is flexible, durable, strong, corrosion resistant, resistant to cathodic disbondment, and impact resistant at the same time. The utility of various polyolefin polymers such as polyethylene or polypropylene is limited by the difficulty of obtaining a resin system that will adhere sufficiently to the polyolefin. It is has been found that for proper wet-ting and adhesion on a solid surface, the surface energy of the solid surface must be at least 10 dynes/cm at 20°C greater than the surface tension of the liquid. For adhesion of polyurethane to polyethylene it is known to surface treat the polyethylene to have a surface tension greater than 40 dynes/cm at 20°C, as described in United States patent no. 4,880,879.
It is also known that the lower the surface tension of the liquid, the better its ability to penetrate crystalline and semi-solid structures and to compete with and dis-place other liquids.
The properties of various fiber reinforced plastics (FRP) are well known in the art. Various fabrics (including woven fiber, unidirectional fiber, or roving fiber) such as fiberglass, carbon fiber, basalt fiber, ceramic fiber, metal filament, aramid fiber, and others are often combined, either by helical wrapping of roving, or by lay-up of woven fiber, with various resin systems to create composites of varying strength, flexibility and durability. Other fibers, including many polyolefins, which have excellent physical properties, have not been used in creating composites because they have surface ener-gies that are too low to make them useful in composite structures.
Composite Device and Method of Making a Composite Device NAME OF INVENTOR
Anthony G. Warren Steuart Scott FIELD OF THE INVENTION
This invention relates to methods of making composite devices, and composite 1o devices made by such methods.
BACKGROUND OF THE INVENTION
Creating protective coatings for pipes, or making pipes or other devices from composite materials, is complicated by the difficulty of obtaining a material that is flexible, durable, strong, corrosion resistant, resistant to cathodic disbondment, and impact resistant at the same time. The utility of various polyolefin polymers such as polyethylene or polypropylene is limited by the difficulty of obtaining a resin system that will adhere sufficiently to the polyolefin. It is has been found that for proper wet-ting and adhesion on a solid surface, the surface energy of the solid surface must be at least 10 dynes/cm at 20°C greater than the surface tension of the liquid. For adhesion of polyurethane to polyethylene it is known to surface treat the polyethylene to have a surface tension greater than 40 dynes/cm at 20°C, as described in United States patent no. 4,880,879.
It is also known that the lower the surface tension of the liquid, the better its ability to penetrate crystalline and semi-solid structures and to compete with and dis-place other liquids.
The properties of various fiber reinforced plastics (FRP) are well known in the art. Various fabrics (including woven fiber, unidirectional fiber, or roving fiber) such as fiberglass, carbon fiber, basalt fiber, ceramic fiber, metal filament, aramid fiber, and others are often combined, either by helical wrapping of roving, or by lay-up of woven fiber, with various resin systems to create composites of varying strength, flexibility and durability. Other fibers, including many polyolefins, which have excellent physical properties, have not been used in creating composites because they have surface ener-gies that are too low to make them useful in composite structures.
SUNflVIARY OF THE INVENTION
According to an aspect of this invention, we have surface treated fabric made of non-woven polyolefin fiber to increase the fabric surface energy, and have used resin systems with low enough surface tension to provide complete wetting. The result is that the resin is 'wicked' throughout the fabric and when cured it creates a unique high performance composite structure that because of the high level of saturation of the resin and fiber is nearly monolithic in structure. Various thermosetting resin sys-1o terns can be used which yield different results in terms of strength, flexibility, impact resistance, ability to bond to other substrates, vapor barrier characteristics, chemical resistance, elongation, and other physical and performance characteristics.
Examples of suitable resin systems include; epoxies, polyurethane, unsaturated polyester, vinyl ester, polydicyclopentadiene, acrylic latex, rubber latex, polysulfide, polyurea, novol acs, and phenolics.
It is therefore desirable to have a polyolefin which has been treated in such a way as to increase its surface energy and a thermosetting resin system with a low enough surface tension to create a high strength bond between the two principal com-ponents of the system. The resulting composite has better performance characteristics 2o than expected of the two components taken separately.
There is therefore provided in accordance with an aspect of the invention, a method of making a composite device or other product. The device can be made by wetting a surface treated strips) polyolefin fabric with a suitable thermosetting resin.
The preferred embodiment is to surface treat a non-woven fabric made of polypropyl-ene fibers. The fabric strips are then wetted with a thermosetting resin system the pri-mary characteristic of which is that it has a surface tension at least 10 dynes/cm at 20°C less than the surface energy of the treated polyolefin fabric. The resin wetted fabric can then be laid into molds or forms, or wrapped around a mandrel.
Alternately the fabric can be laid into molds or forms, or wrapped around a mandrel and then 3o wetted with the appropriate resin system. The object is then allowed to cure, either at ambient temperature or by force curing with the addition of heat.
Composite devices made by the method of the invention are also claimed.
Further summary of the invention is to be found in the claims.
According to an aspect of this invention, we have surface treated fabric made of non-woven polyolefin fiber to increase the fabric surface energy, and have used resin systems with low enough surface tension to provide complete wetting. The result is that the resin is 'wicked' throughout the fabric and when cured it creates a unique high performance composite structure that because of the high level of saturation of the resin and fiber is nearly monolithic in structure. Various thermosetting resin sys-1o terns can be used which yield different results in terms of strength, flexibility, impact resistance, ability to bond to other substrates, vapor barrier characteristics, chemical resistance, elongation, and other physical and performance characteristics.
Examples of suitable resin systems include; epoxies, polyurethane, unsaturated polyester, vinyl ester, polydicyclopentadiene, acrylic latex, rubber latex, polysulfide, polyurea, novol acs, and phenolics.
It is therefore desirable to have a polyolefin which has been treated in such a way as to increase its surface energy and a thermosetting resin system with a low enough surface tension to create a high strength bond between the two principal com-ponents of the system. The resulting composite has better performance characteristics 2o than expected of the two components taken separately.
There is therefore provided in accordance with an aspect of the invention, a method of making a composite device or other product. The device can be made by wetting a surface treated strips) polyolefin fabric with a suitable thermosetting resin.
The preferred embodiment is to surface treat a non-woven fabric made of polypropyl-ene fibers. The fabric strips are then wetted with a thermosetting resin system the pri-mary characteristic of which is that it has a surface tension at least 10 dynes/cm at 20°C less than the surface energy of the treated polyolefin fabric. The resin wetted fabric can then be laid into molds or forms, or wrapped around a mandrel.
Alternately the fabric can be laid into molds or forms, or wrapped around a mandrel and then 3o wetted with the appropriate resin system. The object is then allowed to cure, either at ambient temperature or by force curing with the addition of heat.
Composite devices made by the method of the invention are also claimed.
Further summary of the invention is to be found in the claims.
DETAILED DESCRIPTION OF PREFERRED EMBODIIUVIENTS
A pipe may be made, or protected with a coating, by the method of the inven-tion according to the following method. The method may likewise be applied to make or protect a tank, other containment device or composite device. To make the device, first it is necessary to have a form of the device. The form may be a mandrel, when a pipe is to be made or protected, or a tank, if a tank is to be made or protected. The form may be a pre-existing or new device that is to be protected, as for example a pre-existing tank, whether rusted or damaged, or may be a new device that is to be pro-tected with a coating.
to Next, strips of polyolefin, polyester, polyamide, aramid, polyvinyl chloride, or polystyrene material are obtained. The strips may be made of woven or nonwoven fi-ber, whose cross-sectional dimensions are close to each other, or may be made from a sheet, in which one cross-sectional dimension is much larger than the other.
If a fiber is used, it should have a length of at least 0.5 cm, and a cross-sectional width in the order of 0.1 cm or less. A strip may be made of one or more fibers or sheets.
The material should be surface treated to have a surface energy greater than dynes/cm at 20°C, and preferably greater than 40 dynes/cm at 20°C. Methods of sur-face treatment are in themselves well known in the art, and include exposure to reac-tive gas atmospheres containing Fz, C12, 503, or 03; exposure to oxidative liquids such 2o as nitric acid, sulfuric acid, chromic acid, or H202; or other process such as electro-static discharge, corona discharge, plasma exposure or flame treatment. Other exam-pies are disclosed in United States patent no. 4,880,879.
The strip should also have sufficient flexibility to wrap around a mandrel, as for example a 30 cm mandrel, or more preferably a 5 cm mandrel without fracturing.
The strip should also have a Mullen Burst Strength of at least 100 PSI. Other desirable characteristics of the strip are uniform thickness and tensile strength greater than 100 PSI both along its length and across its width. For application to a pipe, the strip should have a width no greater than the diameter of the pipe, and preferably close to the diameter of the pipe.
3o Once the surface treated strip has been obtained, the strip is soaked in an ep-oxy, such as phenolic resin, for example a novolac. A suitable novolac is SC
modified novolac available from Superior Environmental Technologies of Dallas, Texas. A novolac is as defined in the McGraw-Hill Encyclopedia of Chemistry 1993, p. 806-807. Another suitable epoxy is believed to be DerakaneT"~ epoxy vinyl ester resin available from Dow Plastics. Any thermosetting resin system with a surface ten-sion at least 10 dynes/cm at 20°C less than the surface energy of the fabric could be suitable depending upon the other physical characteristics of the coating that are desir-able. For instance, a Polyurethane/Polyurea hybrid resin such as VFI 200 HB
available from Volatile Free Inc. Waukesha Wis. is believed to perform well. Examples of suit-s able resins that may be usable as described are epoxies, polyurethane, unsaturated polyester, polydicyclopentadiene, vinyl ester, acrylic latex, rubber latex, polysulfide, polyurea, novolacs, and phenolics.
The resin soaked strip is then applied to the mandrel form, or tank form. Ap plication may be carried out by laying strips on the surface of the form. For a pipe, the to strips may be wound on to the pipe in a helical design according to known procedures.
Adjacent flights of the helical strips should overlap, preferably about 50% to give a double thickness of strip. The thickness of the strip is a matter of choice, depending on weight, expense, flexibility and burst resistance requirements. If the form is to be re-moved to make a stand alone composite device, rather than a protected device, the 15 mandrel or tank should first be treated with a mold release agent, many of which are known in the art. The resin is then cured in conventional manner. If the mandrel or tank form has been treated with a mold release agent before application of the resin soaked strip, after curing the mandrel or tank form may be removed to yield a stand alone composite device.
2o Alternatively, the mandrel may be continuously moved within a partially cured coating during application of the soaked strip to the mandrel, thus forming continuous tubing.
To maintain the resin soaked strip in place during curing of the resin, the strip is preferably wrapped in an untreated polymeric film, for example commercially avail 25 able pallet wrap, during curing of the resin.
When loose fibers alone are used, the soaked fibers may be blown on the de-vice to be treated, and then held in place with untreated polymeric film during curing.
If the form is made of a material such as polyethylene, and it is desired to adhere the soaked fibers to the polyethylene surface, then the polyethylene surface should be 3o functionalized in accordance with the teachings of US patent 4,880,879 or other simi-lar methods to have a surface energy which is at least 10 dynes/cm at 20°C greater than the surface tension of the resin.
Immaterial modifications may be made to the invention described here without departing from the essence of the invention.
A pipe may be made, or protected with a coating, by the method of the inven-tion according to the following method. The method may likewise be applied to make or protect a tank, other containment device or composite device. To make the device, first it is necessary to have a form of the device. The form may be a mandrel, when a pipe is to be made or protected, or a tank, if a tank is to be made or protected. The form may be a pre-existing or new device that is to be protected, as for example a pre-existing tank, whether rusted or damaged, or may be a new device that is to be pro-tected with a coating.
to Next, strips of polyolefin, polyester, polyamide, aramid, polyvinyl chloride, or polystyrene material are obtained. The strips may be made of woven or nonwoven fi-ber, whose cross-sectional dimensions are close to each other, or may be made from a sheet, in which one cross-sectional dimension is much larger than the other.
If a fiber is used, it should have a length of at least 0.5 cm, and a cross-sectional width in the order of 0.1 cm or less. A strip may be made of one or more fibers or sheets.
The material should be surface treated to have a surface energy greater than dynes/cm at 20°C, and preferably greater than 40 dynes/cm at 20°C. Methods of sur-face treatment are in themselves well known in the art, and include exposure to reac-tive gas atmospheres containing Fz, C12, 503, or 03; exposure to oxidative liquids such 2o as nitric acid, sulfuric acid, chromic acid, or H202; or other process such as electro-static discharge, corona discharge, plasma exposure or flame treatment. Other exam-pies are disclosed in United States patent no. 4,880,879.
The strip should also have sufficient flexibility to wrap around a mandrel, as for example a 30 cm mandrel, or more preferably a 5 cm mandrel without fracturing.
The strip should also have a Mullen Burst Strength of at least 100 PSI. Other desirable characteristics of the strip are uniform thickness and tensile strength greater than 100 PSI both along its length and across its width. For application to a pipe, the strip should have a width no greater than the diameter of the pipe, and preferably close to the diameter of the pipe.
3o Once the surface treated strip has been obtained, the strip is soaked in an ep-oxy, such as phenolic resin, for example a novolac. A suitable novolac is SC
modified novolac available from Superior Environmental Technologies of Dallas, Texas. A novolac is as defined in the McGraw-Hill Encyclopedia of Chemistry 1993, p. 806-807. Another suitable epoxy is believed to be DerakaneT"~ epoxy vinyl ester resin available from Dow Plastics. Any thermosetting resin system with a surface ten-sion at least 10 dynes/cm at 20°C less than the surface energy of the fabric could be suitable depending upon the other physical characteristics of the coating that are desir-able. For instance, a Polyurethane/Polyurea hybrid resin such as VFI 200 HB
available from Volatile Free Inc. Waukesha Wis. is believed to perform well. Examples of suit-s able resins that may be usable as described are epoxies, polyurethane, unsaturated polyester, polydicyclopentadiene, vinyl ester, acrylic latex, rubber latex, polysulfide, polyurea, novolacs, and phenolics.
The resin soaked strip is then applied to the mandrel form, or tank form. Ap plication may be carried out by laying strips on the surface of the form. For a pipe, the to strips may be wound on to the pipe in a helical design according to known procedures.
Adjacent flights of the helical strips should overlap, preferably about 50% to give a double thickness of strip. The thickness of the strip is a matter of choice, depending on weight, expense, flexibility and burst resistance requirements. If the form is to be re-moved to make a stand alone composite device, rather than a protected device, the 15 mandrel or tank should first be treated with a mold release agent, many of which are known in the art. The resin is then cured in conventional manner. If the mandrel or tank form has been treated with a mold release agent before application of the resin soaked strip, after curing the mandrel or tank form may be removed to yield a stand alone composite device.
2o Alternatively, the mandrel may be continuously moved within a partially cured coating during application of the soaked strip to the mandrel, thus forming continuous tubing.
To maintain the resin soaked strip in place during curing of the resin, the strip is preferably wrapped in an untreated polymeric film, for example commercially avail 25 able pallet wrap, during curing of the resin.
When loose fibers alone are used, the soaked fibers may be blown on the de-vice to be treated, and then held in place with untreated polymeric film during curing.
If the form is made of a material such as polyethylene, and it is desired to adhere the soaked fibers to the polyethylene surface, then the polyethylene surface should be 3o functionalized in accordance with the teachings of US patent 4,880,879 or other simi-lar methods to have a surface energy which is at least 10 dynes/cm at 20°C greater than the surface tension of the resin.
Immaterial modifications may be made to the invention described here without departing from the essence of the invention.
Claims (20)
1. A method of making a composite device, the method comprising the steps of:
providing a form of a composite device;
providing strips made of organic material, in which the strips have been surface treated to have a surface energy which is at least 10 dynes/cm at 20°C
greater than the surface tension of the resin system when in liquid form;
soaking the strips in a curable resin;
applying the soaked strips to the form; and curing the curable resin.
providing a form of a composite device;
providing strips made of organic material, in which the strips have been surface treated to have a surface energy which is at least 10 dynes/cm at 20°C
greater than the surface tension of the resin system when in liquid form;
soaking the strips in a curable resin;
applying the soaked strips to the form; and curing the curable resin.
2. The method of claim 1 in which the resin is selected from the group consisting of epoxies, polyurethane, unsaturated polyester, vinyl ester, polydicyclopentadiene, acrylic latex, rubber latex, polysulfide, polyurea, novolacs, and phenolics.
3. The method of claim 2 in which the organic material is selected from the group consisting of polyolefin, polyester, polyamide, aramid, polyvinyl chloride, or polystyrene.
4. The method of claim 3 in which the form is a mandrel and the strips have sufficient flexibility to wrap around a 30 cm mandrel without fracturing.
5. The method of claim 4 in which the mandrel is treated with a mold release agent before the strip is applied to the mandrel.
6. The method of claim 5 in which the mandrel is removed after the resin is cured, thus forming a pipe.
7. The method of claim 6 in which the mandrel is continuously moved during application of the soaked strips to the mandrel, thus forming continuous tubing.
8. The method of claim 7 in which the organic material is a polyolefin.
9. The method of claim 8 in which the organic material is polypropylene.
10. The method of claim 9 in which the curable resin is a novolac.
11. The method of claim 10 in which the strips are wrapped in a polymeric film during curing of the resin.
12. The method of claim 3 in which the organic material is a polyolefin.
13. The method of claim 3 in which the organic material is polypropylene.
14. The method of claim 3 in which the curable resin is a novolac.
15. The method of claim 3 in which the strips are wrapped in a polymeric film during curing of the resin.
16. The method of claim 3 in which the form is a metal tank.
17. The method of claim 3 in which the strips are sheets of material.
18. The method of claim 3 in which the strips are fibers.
19. A composite device made in accordance with any of claims 1-18.
20. A pipe made in accordance with any of claims 1-18.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002254725A CA2254725A1 (en) | 1998-12-01 | 1998-12-01 | Composite device and method of making a composite device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002254725A CA2254725A1 (en) | 1998-12-01 | 1998-12-01 | Composite device and method of making a composite device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2254725A1 true CA2254725A1 (en) | 2000-06-01 |
Family
ID=29425736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002254725A Abandoned CA2254725A1 (en) | 1998-12-01 | 1998-12-01 | Composite device and method of making a composite device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2254725A1 (en) |
-
1998
- 1998-12-01 CA CA002254725A patent/CA2254725A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |