CA2001082A1 - Method of overwrapping an article with a thermosetting resin - Google Patents
Method of overwrapping an article with a thermosetting resinInfo
- Publication number
- CA2001082A1 CA2001082A1 CA002001082A CA2001082A CA2001082A1 CA 2001082 A1 CA2001082 A1 CA 2001082A1 CA 002001082 A CA002001082 A CA 002001082A CA 2001082 A CA2001082 A CA 2001082A CA 2001082 A1 CA2001082 A1 CA 2001082A1
- Authority
- CA
- Canada
- Prior art keywords
- article
- thermosetting resin
- pipe
- resin
- filament
- 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
Links
- 239000011347 resin Substances 0.000 title claims abstract description 52
- 229920005989 resin Polymers 0.000 title claims abstract description 52
- 229920001187 thermosetting polymer Polymers 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 27
- 229920001169 thermoplastic Polymers 0.000 claims abstract description 14
- 239000004416 thermosoftening plastic Substances 0.000 claims abstract description 14
- 238000001816 cooling Methods 0.000 claims abstract description 7
- 239000011152 fibreglass Substances 0.000 claims description 7
- 238000004140 cleaning Methods 0.000 claims description 3
- 239000007787 solid Substances 0.000 claims description 2
- 239000002904 solvent Substances 0.000 claims description 2
- 239000000126 substance Substances 0.000 description 7
- 229910000831 Steel Inorganic materials 0.000 description 6
- 239000010959 steel Substances 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 239000004743 Polypropylene Substances 0.000 description 4
- -1 polypropylene Polymers 0.000 description 4
- 229920001155 polypropylene Polymers 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- CEJLBZWIKQJOAT-UHFFFAOYSA-N dichloroisocyanuric acid Chemical compound ClN1C(=O)NC(=O)N(Cl)C1=O CEJLBZWIKQJOAT-UHFFFAOYSA-N 0.000 description 2
- 229920001903 high density polyethylene Polymers 0.000 description 2
- 238000011417 postcuring Methods 0.000 description 2
- PRPINYUDVPFIRX-UHFFFAOYSA-N 1-naphthaleneacetic acid Chemical compound C1=CC=C2C(CC(=O)O)=CC=CC2=C1 PRPINYUDVPFIRX-UHFFFAOYSA-N 0.000 description 1
- 101150057388 Reln gene Proteins 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000003518 caustics Substances 0.000 description 1
- NEHMKBQYUWJMIP-UHFFFAOYSA-N chloromethane Chemical compound ClC NEHMKBQYUWJMIP-UHFFFAOYSA-N 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 210000002310 elbow joint Anatomy 0.000 description 1
- 238000009730 filament winding Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000007665 sagging Methods 0.000 description 1
Landscapes
- Laminated Bodies (AREA)
- Lining Or Joining Of Plastics Or The Like (AREA)
Abstract
A S S T R A C T
A method of overwrapping a thermoplastic article with a thermosetting resin is disclosed, comprising the steps of: cooling the article 10 to below ambient temperature; applying a layer of thermosetting resin 13 to the outer surface of the article; and allowing the thermosetting resin to cure.
A method of overwrapping a thermoplastic article with a thermosetting resin is disclosed, comprising the steps of: cooling the article 10 to below ambient temperature; applying a layer of thermosetting resin 13 to the outer surface of the article; and allowing the thermosetting resin to cure.
Description
~o~ z 1 This invention relates to method of overwrapping thermoplastic articles with a synthetlc resin. ~ore particulary, thls invention relates to a method oi overwrapping thermoplastic articles ~or use in chemical plants with a reinforced thermosetting resin.
In chemical plants, hlghly corrosive substances are often conveyed in pipes, tubes or the like. These substances vary from highly acidic to highly alkaline 10 and are understandably damaging to the pipes they are conveyed in.
Use is widely made today of steel pipes, lined on the inside with an inert plastic liner to convey corrosive 15 substances in chemical plants. This type of arrangement suffers from various disadvantages.
For example, the costs of the steel pipes and the seperately manufactured and inserted plastic liners are often prohibitively high. Another disadvantage is the 20 fact that with this type of arrangement, only the inside of the pipe is made corrosion resistant, and not the outside. The corrosive environment of a chemical plant in some areas therefore often causes the steel pipe to corrode rapidly on the outside. A further 25 problem associated with the above arrangement lies in .j ~ - 2 , ';
1 the dl~erence in coeff~cient o~ e~panslon between the steel plpe and lts plastlc liner.
To use a thermoplastic pipe on lts own for the aforesaid purposes also has its disadvantages. The biggest problem wlth using a thermoplastic plpe such as a polypropylene pipe lies in its relatively high coefficient of expansion. The ooefficient of expansion of a polypropylene pipe for e~ample, is about ten times 10 higher than that of a steel pipe and would have to be stiffened in some way to prevent significant e~pænsion and consequent sagging of the pipe when e.g. conveying a heated substance. Another obvious problem with a thermoplastic pipe is its relatively low strength and 15 pressure bearing capabilities compared to steel.
Various methods have been employed in the past to overwrap a thermoplastic pipe with a layer of reinforced themosetting resin in order to overcome the 20 above problems. These methods, however, suffer inter alia, from the disadvantage that the thermosetting layer does not bond well to the outer surface of the pipe.
~0~ 2 1 It is accordingly an ob~ect of the present invention to provide a method of overwrapping a thermoplastlc article wlth a synthetic rasin which applicant believes will overcome or at least minimize the problems and disadvantages of the known arrangements.
According to one aspect of the invention, a method of overwrapping a thermoplastic article with a thermosetting resin comprises the steps of:-- cooling the article to below ambient temperature;
- applying a layer of thermosetting resin to ; 15 the outer surface of the article; and - allowing the thermosetting resin to cure.
Preferably, a reinforced thermosetting resin is applied 20 to the outer surface of the article.
The article is preferably cooled to between 10C and 20C prior to applying the reinforced thermosetting resin.
~o~ z 1 Pre~erably also the method includes the ~urther step o~
strlating at least a portlon of the sur~ace of the artic.le to be overwrapped prior to cooling the article and applylne the reln~orced thermosetting resin.
~ith the above arrangement, the article contracts slightly when cooled down. When the reinforced thermosetting resln is therefore applled to the outer surface of the article, the article is in a slightly 10 contracted state. An exothermic reaction occurs when the thermosetting resin starts to cure and the heat energy radiated as a result of the e~othermic reaction is absorbed by the article. This causes the article to expand slightly while the resin is curing. It will 15 be appreciated that with the above arrangement, the expxnding outer surface of the article causes the striations on the surface ko key permanently into the resin, and when the resin has set, the outer surface bears outwardly against the resin coating. It is 20 therei'ore not ordinarily possible -to remove the resin overwrapping from the article, even if the article is in a symetric shape, such as a length of straight thermoplastic piping.
~0~)~t)8~ `
1 The article may be striated by cuttlng at least ooe groove into the outer surface thereof, and is preferably striated by cutting a continuous hellcal groove into the outer surface thereof by means of a lathe and cutti~g tool arrangement or the like.
The article may be a length of thermoplastic pipe.
With this arrangement, a thermoplastic pipe such as a 10 polypropylene pipe may be overwrapped with a reinforced thermosetting resin in order to render its corrosion resistant, to curtail excessive linear expansion and contraction of the pipe and to increase its strength and pressure bearing capabilities.
The reinforced thermosetting resin may be applied to the article in the form of a fibreglass filament predipped in a thermosetting resin, the resin-carrying filament in use being ~Irapped around the pipe.
The resi.n-carrying filament may initially be wound at an angle of ninety degree~ to the longitudinal a~is of the pipe, whereafter it may be wound to and fro at an angle o fifty five degrees to the longitudinal a~is of 25 the pipe.
~01)~ 32 1 The resin-carrying filament is preferably wrapped onto the plpe until a layer of between 2mm and lOmm of filament and resin is applied to the outer surface of the pipe.
The thermosetting resin may be any one of a polyester-;
vinylester-; isothalic-, or bisphenolic resin.
The method may include the further step of cleaning the 10 outer surface of the article with a suitable solvent prior to applying the thermosetting resin to the outer surface thereof.
The article is preferably cooled down to below ambient 15 temperature by placing it in a bath of solid C02.
The thermosetting resin may be cured by placing the overwrapped article under infra-red heater lamps.
20 According to another aspect of the invention, a thermoplastic article, overwrapped with a thermosetting resin as described is provided.
:~ .
~3~ 3Z
1 One embodlment o~ thls Invention will now be descrlbed in detall wlth reYerence to the accompanyin~ drawings ln which:-Figure 1 - is a partly sectioned perspective vlew o~ a striated pipe to be overwrapped according to the invention;
Figures 2 & 3 are perspective views of the pipe of figure 1 at different stages of overwrapping; and Figure 4 - is a partly sectioned perspective view of the pipe of figure 1 after it has beeo fully overwrapped according to the method of the invention.
Referring now in particular to figure 1, a length of polypropylene pipe lO ~ith a wall thickness of about 3mm 20 is provided and striated by placing the pipe 10 in a lathe (not shown) and cutting a continuous helical groove 11 into the outer surface of pipe 10. The groove 11 is cut O.7mm deep by 1,2mm wide on a spiral pitch oi' 2,5mm. The corners of the groove are not 25 entirely sharp but slightly rounded to minimise stress points or lines from which cracks may propagate.
: - 8 6~
1 The pipe 10 ls then thoroughly cleaned with a suitable organic solvent (not ~hown).
After cleaning, the pipe 10 is placed in a cold bath (not shown) containing dry blocks of C02 until the temperature o e -the pipe 10 is between 12C and 15C.
The cooling operation usually lasts between 20 and 30 seconds, depending on the wall thickness and length of the pipe. The cooling causes the pipe to contract or 10 shrink slightly.
The ccoled pipe 10 is -then located on a two a~is controlled filament winding machine (not shown).
15 The controlled eilament winding machine is well known and standard equipment in the art and is equipped with a supply of fibreglass eilament and a reservoir Oe thermosetting resin. The principle Oe operation Oe the machine is to dip the fibreglass filament in the resin 20 and then to wrap the resin~carrying filament onto the surface of the article to be overwrapped. The machine can be set to wrap the filament at different angles relative to the article.
L)82 l In figure 2, a resin-carrying fibreglass filament 12 is shown to be initially wo~lnd by means of the winding machine (not shown) onto the pipe lO at an angle o~ 90 degrees to the longitudinal axis of the pipe lO. The Eilament 12 th~s pena-trates and fills the groove ll.
Once the groove ll is filled with the resln and the filament l2, the winding machine is set at an angle of fifty five degrees to the longitudinal a~is of the pipe and the filament 12 is wound to and fro along the lO length of the pipe lO until a layer of 5 - 6 mm thick of fibreglass filamen-t and resin is applied to the outer surface of the pipe lO (see figure 3).
Once the desired layer thickness is attained, which is 15 in practice dependant on the temperature and pressure bearing requirements of the final product, the overwrapped pipe lO is removed from the winding machine.
20 During and after the winding opera-tion, the resin starts to cure on the pipe lO. The setting of the resin, which may be any one of a polyester-, vinylester-, isothalic-, or bisphenolic-resin, causes an exothermic reaction to take place~ thereby radiating 2C~ 2 1 heat energy which is absorbed by the plpe 10. This heat energy causes the temperature o~ the pipe 10 to increase with a resultant e~pansion oi the pipe 10.
The striated outer suriace of the pipe 10 therefore e~pands and keys permanently into the rein~orced resin overwrapping, and bears firmly against the overwrapp~ng when it is ~ully cured.
After winding, the pipe 10 is pre~cured under infra-red 10 heater lamps until the resin coating is dry enough to be handled. After the pre-cure, a post-curing period follows wherein the overwrapped pipe is left at ambient temperature until fully cured. The post-curing operation may alternatively also take place under 15 infra-red heater lamps.
Figure 4 shows an overwrapped pipe 10 wherein the groove 11 is fully keyed into the layer 13 of fibreglass filament and resin.
Once the overwrapping operation as described above is completed, the layer 13 cannot be removed from the pipe 10. The overwrapping serves to stiffen the pipe 10, increases its overall strength and pressure bearing 25 capabilities a~d curtails its e~pansion and contractlon tendencles in use.
20~ ~)82 1 It will be appreciated that many modifications and/or variations oE the invention May be possible without departing Erom the scope of the appended claims. For e~ample, instead o~ striating the outer surface of the pipe with a helical groove, circular grooves, notches, knurls or burrs, etc., may be applied. Also, T-joints, elbow joints or other types of pipe fittings may be overwrapped by means of this method.
In chemical plants, hlghly corrosive substances are often conveyed in pipes, tubes or the like. These substances vary from highly acidic to highly alkaline 10 and are understandably damaging to the pipes they are conveyed in.
Use is widely made today of steel pipes, lined on the inside with an inert plastic liner to convey corrosive 15 substances in chemical plants. This type of arrangement suffers from various disadvantages.
For example, the costs of the steel pipes and the seperately manufactured and inserted plastic liners are often prohibitively high. Another disadvantage is the 20 fact that with this type of arrangement, only the inside of the pipe is made corrosion resistant, and not the outside. The corrosive environment of a chemical plant in some areas therefore often causes the steel pipe to corrode rapidly on the outside. A further 25 problem associated with the above arrangement lies in .j ~ - 2 , ';
1 the dl~erence in coeff~cient o~ e~panslon between the steel plpe and lts plastlc liner.
To use a thermoplastic pipe on lts own for the aforesaid purposes also has its disadvantages. The biggest problem wlth using a thermoplastic plpe such as a polypropylene pipe lies in its relatively high coefficient of expansion. The ooefficient of expansion of a polypropylene pipe for e~ample, is about ten times 10 higher than that of a steel pipe and would have to be stiffened in some way to prevent significant e~pænsion and consequent sagging of the pipe when e.g. conveying a heated substance. Another obvious problem with a thermoplastic pipe is its relatively low strength and 15 pressure bearing capabilities compared to steel.
Various methods have been employed in the past to overwrap a thermoplastic pipe with a layer of reinforced themosetting resin in order to overcome the 20 above problems. These methods, however, suffer inter alia, from the disadvantage that the thermosetting layer does not bond well to the outer surface of the pipe.
~0~ 2 1 It is accordingly an ob~ect of the present invention to provide a method of overwrapping a thermoplastlc article wlth a synthetic rasin which applicant believes will overcome or at least minimize the problems and disadvantages of the known arrangements.
According to one aspect of the invention, a method of overwrapping a thermoplastic article with a thermosetting resin comprises the steps of:-- cooling the article to below ambient temperature;
- applying a layer of thermosetting resin to ; 15 the outer surface of the article; and - allowing the thermosetting resin to cure.
Preferably, a reinforced thermosetting resin is applied 20 to the outer surface of the article.
The article is preferably cooled to between 10C and 20C prior to applying the reinforced thermosetting resin.
~o~ z 1 Pre~erably also the method includes the ~urther step o~
strlating at least a portlon of the sur~ace of the artic.le to be overwrapped prior to cooling the article and applylne the reln~orced thermosetting resin.
~ith the above arrangement, the article contracts slightly when cooled down. When the reinforced thermosetting resln is therefore applled to the outer surface of the article, the article is in a slightly 10 contracted state. An exothermic reaction occurs when the thermosetting resin starts to cure and the heat energy radiated as a result of the e~othermic reaction is absorbed by the article. This causes the article to expand slightly while the resin is curing. It will 15 be appreciated that with the above arrangement, the expxnding outer surface of the article causes the striations on the surface ko key permanently into the resin, and when the resin has set, the outer surface bears outwardly against the resin coating. It is 20 therei'ore not ordinarily possible -to remove the resin overwrapping from the article, even if the article is in a symetric shape, such as a length of straight thermoplastic piping.
~0~)~t)8~ `
1 The article may be striated by cuttlng at least ooe groove into the outer surface thereof, and is preferably striated by cutting a continuous hellcal groove into the outer surface thereof by means of a lathe and cutti~g tool arrangement or the like.
The article may be a length of thermoplastic pipe.
With this arrangement, a thermoplastic pipe such as a 10 polypropylene pipe may be overwrapped with a reinforced thermosetting resin in order to render its corrosion resistant, to curtail excessive linear expansion and contraction of the pipe and to increase its strength and pressure bearing capabilities.
The reinforced thermosetting resin may be applied to the article in the form of a fibreglass filament predipped in a thermosetting resin, the resin-carrying filament in use being ~Irapped around the pipe.
The resi.n-carrying filament may initially be wound at an angle of ninety degree~ to the longitudinal a~is of the pipe, whereafter it may be wound to and fro at an angle o fifty five degrees to the longitudinal a~is of 25 the pipe.
~01)~ 32 1 The resin-carrying filament is preferably wrapped onto the plpe until a layer of between 2mm and lOmm of filament and resin is applied to the outer surface of the pipe.
The thermosetting resin may be any one of a polyester-;
vinylester-; isothalic-, or bisphenolic resin.
The method may include the further step of cleaning the 10 outer surface of the article with a suitable solvent prior to applying the thermosetting resin to the outer surface thereof.
The article is preferably cooled down to below ambient 15 temperature by placing it in a bath of solid C02.
The thermosetting resin may be cured by placing the overwrapped article under infra-red heater lamps.
20 According to another aspect of the invention, a thermoplastic article, overwrapped with a thermosetting resin as described is provided.
:~ .
~3~ 3Z
1 One embodlment o~ thls Invention will now be descrlbed in detall wlth reYerence to the accompanyin~ drawings ln which:-Figure 1 - is a partly sectioned perspective vlew o~ a striated pipe to be overwrapped according to the invention;
Figures 2 & 3 are perspective views of the pipe of figure 1 at different stages of overwrapping; and Figure 4 - is a partly sectioned perspective view of the pipe of figure 1 after it has beeo fully overwrapped according to the method of the invention.
Referring now in particular to figure 1, a length of polypropylene pipe lO ~ith a wall thickness of about 3mm 20 is provided and striated by placing the pipe 10 in a lathe (not shown) and cutting a continuous helical groove 11 into the outer surface of pipe 10. The groove 11 is cut O.7mm deep by 1,2mm wide on a spiral pitch oi' 2,5mm. The corners of the groove are not 25 entirely sharp but slightly rounded to minimise stress points or lines from which cracks may propagate.
: - 8 6~
1 The pipe 10 ls then thoroughly cleaned with a suitable organic solvent (not ~hown).
After cleaning, the pipe 10 is placed in a cold bath (not shown) containing dry blocks of C02 until the temperature o e -the pipe 10 is between 12C and 15C.
The cooling operation usually lasts between 20 and 30 seconds, depending on the wall thickness and length of the pipe. The cooling causes the pipe to contract or 10 shrink slightly.
The ccoled pipe 10 is -then located on a two a~is controlled filament winding machine (not shown).
15 The controlled eilament winding machine is well known and standard equipment in the art and is equipped with a supply of fibreglass eilament and a reservoir Oe thermosetting resin. The principle Oe operation Oe the machine is to dip the fibreglass filament in the resin 20 and then to wrap the resin~carrying filament onto the surface of the article to be overwrapped. The machine can be set to wrap the filament at different angles relative to the article.
L)82 l In figure 2, a resin-carrying fibreglass filament 12 is shown to be initially wo~lnd by means of the winding machine (not shown) onto the pipe lO at an angle o~ 90 degrees to the longitudinal axis of the pipe lO. The Eilament 12 th~s pena-trates and fills the groove ll.
Once the groove ll is filled with the resln and the filament l2, the winding machine is set at an angle of fifty five degrees to the longitudinal a~is of the pipe and the filament 12 is wound to and fro along the lO length of the pipe lO until a layer of 5 - 6 mm thick of fibreglass filamen-t and resin is applied to the outer surface of the pipe lO (see figure 3).
Once the desired layer thickness is attained, which is 15 in practice dependant on the temperature and pressure bearing requirements of the final product, the overwrapped pipe lO is removed from the winding machine.
20 During and after the winding opera-tion, the resin starts to cure on the pipe lO. The setting of the resin, which may be any one of a polyester-, vinylester-, isothalic-, or bisphenolic-resin, causes an exothermic reaction to take place~ thereby radiating 2C~ 2 1 heat energy which is absorbed by the plpe 10. This heat energy causes the temperature o~ the pipe 10 to increase with a resultant e~pansion oi the pipe 10.
The striated outer suriace of the pipe 10 therefore e~pands and keys permanently into the rein~orced resin overwrapping, and bears firmly against the overwrapp~ng when it is ~ully cured.
After winding, the pipe 10 is pre~cured under infra-red 10 heater lamps until the resin coating is dry enough to be handled. After the pre-cure, a post-curing period follows wherein the overwrapped pipe is left at ambient temperature until fully cured. The post-curing operation may alternatively also take place under 15 infra-red heater lamps.
Figure 4 shows an overwrapped pipe 10 wherein the groove 11 is fully keyed into the layer 13 of fibreglass filament and resin.
Once the overwrapping operation as described above is completed, the layer 13 cannot be removed from the pipe 10. The overwrapping serves to stiffen the pipe 10, increases its overall strength and pressure bearing 25 capabilities a~d curtails its e~pansion and contractlon tendencles in use.
20~ ~)82 1 It will be appreciated that many modifications and/or variations oE the invention May be possible without departing Erom the scope of the appended claims. For e~ample, instead o~ striating the outer surface of the pipe with a helical groove, circular grooves, notches, knurls or burrs, etc., may be applied. Also, T-joints, elbow joints or other types of pipe fittings may be overwrapped by means of this method.
Claims (15)
1. A method of overwrapping a thermoplastic article with a thermosetting resin comprising the steps of:
cooling the article to below ambient temperature;
applying a layer of thermosetting resin to the outer surface of the article; and allowing the thermosetting resin to cure.
cooling the article to below ambient temperature;
applying a layer of thermosetting resin to the outer surface of the article; and allowing the thermosetting resin to cure.
2. A method as claimed in claim 1 wherein a reinforced thermosetting resin is applied to the outer surface of the article.
3. A method as claimed in claim 1 wherein the article is cooled to between 10°C and 20°C prior to applying the thermosetting resin.
4. A method as claimed in claim 1 including the further step of striating at least a portion of the surface of the article to be overwrapped prior to cooling the article and applying the thermosetting resin.
5. A method as claimed in claim 4 wherein the surface is striated by cutting at least one groove therein.
6. A method as claimed in claim 4 wherein the surface is striated by cutting a continuous helical groove therein.
7. A method as claimed in claim 1 wherein the article comprises a length of thermosplastic pipe.
8. A method as claimed in claim 7 wherein the reinforced thermosetting resin is applied to the pipe in the form of a fibreglass filament predipped in a thermosetting resin, the resin-carrying filament in -use being wrapped around the pipe.
9. A method as claimed in claim 8 wherein the resin-carrying filament is initially wound at an angle of ninety degrees to the longitudinal axis of the pipe whereafter it is wound to and fro at an angle of fifty five degrees to the longitudinal axis of the pipe.
10. A method as claimed in claim 9 wherein the resin-carrying filament is wrapped onto the pipe until a layer of between 2mm an 10mm of filament and resin is applied to the outer surface of the pipe.
11. A method as claimed in claim 1 wherein the thermosetting resin comprises any one of a polyester-; vinylester-; isothalic-; or bisphenolic resin.
12. A method as claimed in claim 1 including the further step of cleaning the outer surface of the article with a suitable solvent prior to applying the thermosetting resin to the outer surface thereof.
13. A method as claimed in claim 1 wherein the article is cooled down below ambient temperature by placing it in a bath of solid CO2.
14. A method of as claimed in claim 1 wherein the thermosetting resin is cured by placing the overwrapped article under infra-red heater lamps.
15. A thermoplastic article overwrapped with a thermosetting resin in accordance with a method as claimed in anyone of claims 1 to 14.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002001082A CA2001082A1 (en) | 1989-10-20 | 1989-10-20 | Method of overwrapping an article with a thermosetting resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002001082A CA2001082A1 (en) | 1989-10-20 | 1989-10-20 | Method of overwrapping an article with a thermosetting resin |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2001082A1 true CA2001082A1 (en) | 1991-04-20 |
Family
ID=4143366
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002001082A Abandoned CA2001082A1 (en) | 1989-10-20 | 1989-10-20 | Method of overwrapping an article with a thermosetting resin |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2001082A1 (en) |
-
1989
- 1989-10-20 CA CA002001082A patent/CA2001082A1/en not_active Abandoned
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 19940420 |