EP0621883A1 - Systemes de resines durcissables et applications correspondantes - Google Patents

Systemes de resines durcissables et applications correspondantes

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Publication number
EP0621883A1
EP0621883A1 EP93902407A EP93902407A EP0621883A1 EP 0621883 A1 EP0621883 A1 EP 0621883A1 EP 93902407 A EP93902407 A EP 93902407A EP 93902407 A EP93902407 A EP 93902407A EP 0621883 A1 EP0621883 A1 EP 0621883A1
Authority
EP
European Patent Office
Prior art keywords
resin
pipe
catalyst
liner
curing
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.)
Withdrawn
Application number
EP93902407A
Other languages
German (de)
English (en)
Inventor
Brian Burnett Chandler
David Campbell Mitchell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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
Priority claimed from EP92810029A external-priority patent/EP0551790A1/fr
Application filed by Individual filed Critical Individual
Priority to EP93902407A priority Critical patent/EP0621883A1/fr
Priority claimed from PCT/GB1993/000107 external-priority patent/WO1993015131A2/fr
Publication of EP0621883A1 publication Critical patent/EP0621883A1/fr
Withdrawn legal-status Critical Current

Links

Definitions

  • This invention relates generally to curable resins and more particularly to resins which have been conditioned in order that they may be cured to produce rigid articles in a most convenient and efficient manner.
  • curable synthetic resins to produce rigid articles is extensive, indeed nearly all plastics whilst too numerous to mention here, are synthetic resins initially, which means that they go through a liquid or plastic phase before being shaped and hardened into the final article.
  • lining tube or pipe a resin absorbent tubular structure
  • the impregnated lining tube is inflated (by gas such as air, steam and/or liquid such as water) against the jl pipeline or passway surface whilst the resin is uncured, and whilst the lining tube is so held in position, the resin is allowed or caused to cure whereby the cured resin with the absorbent tubular structure embedded therein forms a self
  • SUBSTITUTE SHEET supporting rigid pipe which may or may not bond to the pipeline or passageway wall.
  • the purpose of this operation is to rehabilitate and/or repair the passageway or pipeline.
  • a particular advantage of the provision of a self supporting rigid pipe is that bonding to the existing pipeline is not necessary, as is the case with some lining systems but it is to be mentioned that this invention can be applied to pipe ⁇ lining systems where the impregnated tube does bond to the existing pipeline or passageway, such systems being those wherein the lining tube is of relatively small thickness e.g. 5 mm or less and the resin acts like a bonding medium rather than an impregnating medium.
  • the lining tube when the resin is in the uncured state may not strictly be a tube in that it may be a web folded into tubular form so that its edges overlap and such edges become fused or held relatively together only when curing in place has been effected.
  • this arrangement provides the advantage that the overlapping edges can slip relatively as the tube is being inflated so that the tube will best fit to the passageway surface.
  • the resin should be cured as fast as possible, as the sooner the resin cures, the sooner the contractor can leave the site. It is to be noted that the contractor will often be given or will often quote a relatively short time for completion of the work, usually undertaken during the night. It is very important therefore that the work be completed in the shortest possible time, especially in these cases where the performance of the work involves the rendering inoperative (as it does in many cases) of a sewage system or the blocking or obstructing of traffic.
  • the contractor must on the one hand have a factory or plant at which the tube is impregnated, a vehicle for keeping the impregnated tube refrigerated and a vehicle with a heating means for heating the fluid which inflates the tube when in place, in order to effect the curing of the resin, as well as the necessary equipment for putting the tube into place.
  • Light radiation curable resins however include catalysts which are activatable by the suns rays and therefore the impregnated lining tubes must be contained in opaque wrappings during storage and transportation to avoid premature curing.
  • Light radiation curable resin does however have the advantage that curing of same can be controlled and theoretically has an infinite shelf life.
  • the flowing liquid in the pipeline or passageway is opaque, as sewage is, it must be diverted and the use of light curing equipment suffers from the same disadvantage in this respect as heating methods. For these reasons, in practice, light curing of in place impregnated lining tubes has not been successful and has not replaced the traditional heating methods.
  • the present invention seeks to provide curable resin systems for the production of rigid articles wherein the resin can be cured readily and quickly, but retains a long to infinite shelf life (e.g. one year or more) making it particularly suitable for use in cured in place lining systems for pipelines and passageways; the invention at this time is not however to be considered as limited to this field of application and it is useable in any circumstances as appropriate where resin is to be formed into a rigid article.
  • a long to infinite shelf life e.g. one year or more
  • the resin in its most general aspect includes or is located adjacent inert matter which is not affected by ambient conditions such as ambient heat and light, but such matter is susceptible to applied radiation to such an extent to cause curing or commencement of curing of the resin.
  • the matter may comprise microencapsulation shells in which is contained a catalyst for the resin, the shells being susceptible to the ultrasonic radiation to rupture the cells to release the catalyst, and hence cause commencement of the cure.
  • the added matter may be magnetic/metallic particles or the like and may be susceptible to alternating electromagnetic radiation to magnetise same according to the well known hysteresis effect, and the hysteresis loss shows up as heating of the particles, and the heat in turn causes the resin to cure or commence its cure.
  • the matter may be electrically conductive and/or magnetisable fibres and/or filaments which form current or magnetisable loops whereby, upon being subjected to alternating electromagnetic radiation, induced currents and/or induced hysteresis effects occur which cause the added matter to heat up and the heating effect cures the resin or causes commencement of the curing of the resin.
  • the various forms of matter may be used together and the resulting resin may be treated by the various forms of radiation simultaneously or in sequence.
  • the magnetisable conductive, magnet and/or metallic particles or fibres may be embodied in the micro encapsulation shells or the catalyst trapped therein in addition or as an alternative to being embodied in the resin.
  • the resins include microencapsulation shells or coatings which are ruptured by ultrasonic energy
  • the invention provides a method of curing to produce cured resin articles; specifically but not exclusively uncured replacement pipe including the microencapsulated catalyst.
  • Such a pipe is inserted into an existing pipeline or passageway to be relined and then cured after application of ultrasonic energy to release the catalyst.
  • a method of curing resinous material including microencapsulated catalysts to yield a rigid cured resin article is provided.
  • the resin is formulated with catalysts, initiators and inhibitors which provide a thermally stable resin with a sensitivity to ultrasound.
  • the resin includes microencapsulated catalyst which will not be released to contact the monomer until application of ultrasonic energy to release the catalyst or promoter and initiate the curing.
  • the microencapsulated catalyst is admixed with a curable resinous material disposed in a fibrous carrier layer having at least one lining layer.
  • the fibrous carrier can take the shape of any desired article, such as a boat or molded part for a vehicle.
  • the fibrous carrier is a part of a lining pipe to be installed within an existing conduit needing to be relined.
  • the lining pipe is inserted into the existing conduit, it is inflated by the application of fluid under pressure so that the lining pipe conforms to the inner dimensions of the existing conduit. Installation may involve everting of the lining pipe.
  • the fluid is preferably water which maintains the lining pipe inflated as an ultrasonic device is moved through the water inside the lining pipe to apply ultrasonic energy to release the microencapsulated catalyst to initiate the cure of the resinous material.
  • Another object of this aspect of the invention is to provide an improved lining pipe and method for installing the lining pipe in existing conduits.
  • Still another object of this aspect of the invention is to provide an improved method to install a lining pipe which is cured after application of ultrasonic energy to release the catalyst.
  • Fig. 1 is a cross-section of an impregnated lining pipe in accordance with the invention and when in a flattened condition;
  • Fig. 1A is an enlarged cross sectional view of part of the lining pipe shown in Fig. 1;
  • Fig. IB is a still further enlarged view of one of the microcapsules used in the resin system of Fig. 1A;
  • Fig. 1C is a view similar to Fig. IB, but showing a modified arrangement
  • FIG. 2A, 2B and 2C are schematic drawings illustrating the steps of installing the lining pipe in an existing pipeline and curing it in accordance with the invention
  • Fig. 3 is a perspective view of an ultrasonic curing device suitable for curing the resin including the microencapsulated catalyst in accordance with the invention
  • Fig. 4 is a perspective view of a multiple transducer ultrasonic curing device for use in curing the resin including microencapsulated catalyst in accordance with the invention
  • Figs. 5 and 7 are respectively a cross-section along line I-I of Fig. 7 and an axial section along line III-III of Fig. 5 of a round concrete pipe IX and of a sleeve-like liner 2X according to this aspect of the invention provided in pipe IX, and showing also, partly in axial section in Fig. 7, apparatus 10X according to the invention used during a pipe lining operation;
  • Fig. 6 is a sectional view on an enlarged scale of a portion of the lining 2X shown in Figs. 5 and 7;
  • Fig. 8 is top end view and Fig. 9 is a side view of another apparatus used during a lining operation.
  • a resin article arranged in accordance with the invention can include a resin portion disposed on one or between two lining layers. At least the inner liner should be impermeable tothe resin and fluids to be encountered in the curing process.
  • the resin section can include a carrier, which may be fibrous, containing the curable resin material with microencapsulated catalyst dispersed therein.
  • thermosetting resin compositions that will cure in the presence of a catalyst are suitable.
  • examples include allyl, bimaleimide, epoxy, phenolic, polyester, polyamide, polyurethane, or silicone resins and combinations thereof.
  • the carrier can be any acceptable fibrous material, such as felt and the like, or a web or mesh and the like and the resin section will become rigid and strong once the resin is cured.
  • Thermosetting unsaturated polyester resin compositions are particularly well suited for use in accordance with the invention.
  • Unsaturated polyesters are extremely versatile and can be acceptably rigid, corrosion resistant and weather resistant for many applications, including replacement pipe applications.
  • Such unsaturated polyester resins have been used widely in applications such as constructing boats, exterior automotive parts and bowling balls.
  • unsaturated polyester resins include an unsaturated polyester dissolved in cross-linking monomer and generally contain an inhibitor to prevent cross-linking until the resin is to be cured.
  • the unsaturated polyester is the condensation product of an unsaturated dibasic acid (typically maleic anhydride) and a glycol.
  • the degree of unsaturation varies by including a saturated dibasic acid, such as phthalic anhydride, isophthalic acid or adipic acid.
  • the glycol is usually propylene glycol, ethylene glycol, diethylene, dipropylene glycol, neopentyl glycol and various combinations thereof.
  • Styrene is a particularly well suited cross-linking monomer.
  • Other acceptable cross-linking monomers include vinyl toluene, methacrylate, alpha methyl styrene and diallyl phthalate.
  • Conventional inhibitors include hydroquinone, parabenzoquinone and tertiary butyl catechol.
  • chemical resistance can be achieved by using isophthalic acid, neopentyl glycol, trimethyl pentanediol and hydrogenated bisphenol A.
  • Weathering resistance can be improved by using neopentyl glycol, methyl methacrylate and ultraviolet absorbers, such as fenzophenones and benzotriazoles.
  • Polyester resin is cured by a free radical addition reaction.
  • Organic peroxides can serve as a catalyst and can be the source of the free radicals. At elevated temperatures, heat decomposes the peroxide to produce the free radicals .
  • Peroxyesters and benzoyl peroxide are organic peroxides used at elevated temperatures.
  • the resin component can also include a curing promoter.
  • the promoter can cause the organic peroxide to decompose and form free radicals.
  • Cobalt octoate is an appropriate promoter, generally used with methyl ethyl ketone peroxide (MEKP) as the catalyst. When benzoyl peroxide is used as the catalyst, diethylaniline or dimethylaniline is used as promoters.
  • Epoxy resins are also well suited to be included in the resin section of replacement pipe constructed in accordance with embodiments of the invention.
  • the term epoxy resin refers to a variety of cross-linking materials that contain the epoxy or oxirane group.
  • the epoxy group is reactive with a wide variety of curing agents or hardeners.
  • the curing reaction converts the low molecular weight resin into a three dimensional thermoset structure.
  • Standard epoxy resins are based on bisphenol A and epichlorohydrin as raw materials. Other types are based on the epoxidation of multifunctional structures derived from phenols and formaldehyde or aromatic amines and aminophenols.
  • Epoxy resins can be cured at low temperatures with aliphatic polyamines or polyamides. Cures at elevated temperatures can occur with anhydrides, carboxylic acids, phenol novolac resins, aromatic amines or melamine, urea and phenol- formaldehyde condensates. Cures at lower temperatures generally require a two component system including resin separated from hardener prior to the curing reaction. Cures at elevated temperatures can be performed with a one component mixture of ingredients which will be stable at ambient temperatures. These are more suitable for increasing the pot-life of the resin.
  • Intermediate molecular weight solid epoxy resins can be cured through both the terminal epoxy group and the pendant hydroxyl group in the polymer backbone.
  • Typical cross- linking agents include dicyandiamide or phenolic group terminated poly(hydroxyethers) with imidazole accelerators.
  • Medium molecular weight resins can also be utilized to form epoxy esters by reaction with fatty acids at high temperatures, whereby both the terminal epoxy groups and the secondary hydroxyl groups are converted to ester linkages, the latter by azeotropic removal of water.
  • Other intermediate molecular weight epoxy resins are prepared by chain extension of liquid epoxy resins and brominated bisphenol A.
  • High molecular weight epoxy resins which can be classified as poly(hydroxy) ethers), contain low concentrations of epoxy end groups . They are cured via the hydroxyl groups, typically with aminoplasts (melamine or urea-formaldehyde resins) or phenoplasts (phenol-formaldehyde resins) at elevated temperatures.
  • aminoplasts melamine or urea-formaldehyde resins
  • phenoplasts phenol-formaldehyde resins
  • thermosetting resin compositions formulated without initiators or retardants, provide a particularly well suited base resin material for replacement pipes having long pot-life and can be cured by application of ultrasonic waves.
  • the pot-life of a resin composition used in conventional replacement pipes can be increased significantly by using considerably less, such as less than 50% of a conventional amount of initiator.
  • the pot life is extended by encapsulting the catalysts or initiators and releasing these by application of sonic energy.
  • Cure initiators should be chosen to given the resin a long pot-life and for their chemical sensitivity to ultrasound.
  • Conventional resin formulations for replacement pipes include initiators having activation temperatures in the range of about 40-60°C.
  • pot-life can be increased by employing initiators having activation temperatures in the range of 100-200°C and more preferably 100-150°C.
  • the resin should not be heated to the extent that it will begin to degrade. This will enable the replacement pipe liner to be wet out in quality controlled factory conditions and to be safe from curing until activated with ultrasound.
  • the carrier portion of the resin section preferably has a fibrous sheet structure including a mat, a web or randomly oriented fibers.
  • the fibers can include glass and/or natural and synthetic fibers and the fibers may be of differing denier.
  • a felt-like mat or web or randomly oriented fibers is particular well suited for storing acceptable quantities of resin so that a wetted out web or mat absorbs a maximum amount of resin.
  • a preferable carrier includes a needled felt of synthetic plastic material fibers which may optionally include filament reinforcement. Other constructions which provide a tube of uncured resin and do not employ a fibrous carrier are also acceptable.
  • the carrier can be combined with the resin material by charging a quantity of resin into the inside portion of a carrier tube and if necessary, by applying vacuum to the tube to remove air from the carrier.
  • the tube can then be compressed, such as by passing the tube through nip rollers in order to insure even distribution of the resin in the carrier material.
  • the flexible resinous pipe After the flexible resinous pipe is installed in a tubular shape in the pipeline, it is maintained in an expanded condition by application or pressurized fluid, such as water flowing naturally through the existing pipeline or added from an external source.
  • the pipe can include liners on both the interior and exterior sides thereof.
  • the inner liner should be impervious to fluids. It is preferable to ultrasonically cure the resin in the replacement pipe which can be done in the presence of the usual fluid in the conduit.
  • the method of installing replacement pipe in accordance with the invention can be applied to virtually any situation in which a pipeline, conduit or other passageway is to be repaired.
  • the process is best illustrated by describing the rehabilitation of sewer pipelines.
  • Sewer pipes can vary in diameter from 6 inches to several feet and are normally laid at a gradient with manholes at junctions and bends.
  • a soft-liner replacement pipe formed with thermosetting resin material and felt is manufactured, with reinforcement or other composite materials if required, to match the internal dimensions of the existing pipeline. At least the inside of the replacement pipe will include an impervious membrane to seal the replacement pipe during the installation procedure. The replacement pipe is then taken to the installation site and installed by either a pull-in or an inversion method.
  • the length of existing pipeline to be repaired is cleaned by access through local manholes.
  • the natural flow of liquid through the pipeline is typically bypassed so that installation can be accomplished in an empty pipe.
  • installation methods in which the naturally flowing fluid is the inverting medium in accordance with the invention are advantageous when this cannot be accomplished.
  • the catalyst generally must be one which is not water soluble.
  • the catalyst can be in organic peroxide such as MEKP or benzoyl peroxide and is isolated within the microencapsulated particles. Any suitable capsule covering that can be ruptured by application of sonic energy, such as gelatin, can be used to form the microencapsulted particles.
  • the resin impregnated carrier When the resin impregnated carrier is formed into the desired shape for the construction of a rigid resin article or the replacement pipe is inflated within the existing conduit by a fluid, a suitable ultrasonic element is introduced into the fluid and ultrasonic energy is- released to create cavi-tation bubbles throughout the liquid medium during sonication.
  • Ultrasound is transmitted through the medium by waves which alternately compress and stress the molecular structure of the medium through which the wave passes.
  • This stretching action during the rarefaction cycle of the wave is so powerful that the structure of the liquid medium will be literally torn apart to form microbubbles.
  • extremely high energies are generated inside the bubbles. These involve pressures of hundreds of atmospheres and temperatures of thousands of degrees.
  • the mechanical and chemical effects of the collapsing bubbles are complex, but the end result can be the rupture of the encapsulation shells and the significant enhancement of chemical activity.
  • This energy releases the microencapsulated catalyst so that the catalyst contacts the resin to initiate cure.
  • the ultrasonic energy may also assist and in combination with the catalyst and any promoters present to accelerate the curing of the resin material.
  • the ultrasound applied to release the catalyst is generally in the frequency reange between about 5 to 500 kHz, and preferably between about 20 and 100 kHz.
  • the generation of these ultrasound waves is normally by electrically driven transducers employing piezoelectric elements. These piezoelectric elements, such as PZT disks, expand and contract when subjected to reversing electric voltage.
  • the piezoelectric elements can be sandwiched between metallic disks to form transducers which can be tuned to general particular frequencies of ultrasound.
  • a 25kHz transducer immersed in water will transmit an ultrasonic wave at 1450 m/s having a wave length of 5.8 cm for hundreds of meters.
  • the transducer If the transducer is positioned in a pipe filled with water, reflections will take place at the pipe walls and complex propagation will take place within the pipe, including guided and standing waves. It can be advantageous to line the walls of the existing pipeline with high density material to enhance the ultrasound curing effectiveness and release of the catalyst.
  • High power ultrasound can be generated by multiple transducers mounted on a suitable mandrel whereby special cylinders energized by push-pull transducer arrangements.
  • the several kilowatts of power ultrasound requires to rupture the capsules, release the catalyst and induce increased chemical activity can be attained with conventional ultrasound technology.
  • the microcapsules may be produced by mixing the catalysts and the shell material e.g. gelatin in accordance with the methods set forth in U.S. Patents Nos 4,101,501; 4,154,774 and 4,362,566.
  • the catalysts and gelatin may be mixed in a ratio 12 to 1.
  • Fig. 1 is a cross-section of a tubular lining pipe 10 in a flattened condition.
  • Lining pipe 10 includes an inner tube 5, and outer tube 6 with a fibrous felt absorbent carrier 7 impregnated with resin 8 including microencapsulated catalyst dispersed therein.
  • a cross section of the lining pipe 10 shown in Fig. 1 is shown in diagrammatic and enlarged scale in Fig. 1A.
  • the inner and outer membranes 5 and 6 are clearly shown, and the fibrous felt is indicated by a number of semi-randomly orientated fibres 7A which as illustrated extend generally in a direction transverse to the membranes 5 and 6. This is due.to the process of manufacturing the felt involving needling which means that needles or barbs are punched through fibrous layers in order substantially to align but also to entangle the fibres 7A. Only relatively few fibres are illustrated in order to simplify the illustration.
  • the resin 8 fills the space between the membranes 5 and 6 as shown, and thoroughly impregnates the felt 7.
  • microcapsules 8A are also included within the resin and again only relatively few of these microcapsules are shown but it will be understood that they are extensively and evenly distributed throughout the resin. It should be mentioned at this point that the microcapsules can either be embodied in the resin and dispersed throughout the resin before the resin is applied to the felt 7, or alternatively the microcapsules can be distributed throughout the felt before impregnation with the resin. Indeed in some embodiments it may be possible to embody the microcapsules in the fibres 7A of the felt. This may involve producing the fibres by an extrusion process involving a hollow needle through which the microcapsules are fed. The extrusion process may be in the nature of co-extrusion.
  • microcapsules can be variously utilised both in the resin and in the fibres and some microcapsules may be applied to the felt and some may be mixed with the resin before the resin is applied to the felt.
  • the microcapsules may typically be of 0.4 micron diameter.
  • Fig. IB has been included, and this shows in greatly enlarged detail a single microcapsule and it will be seen to comprise a core 7B of the appropriate catalyst for the resin 8, and a coating or shell 7C which traps the catalyst 7B until it is to be released as will be explained hereinafter.
  • the shell of coating 7C is of a material which is basically inert to ambient conditions so that it will not deteriorate or rupture unless acted upon in the manner according to the present invention and as will be described hereinafter.
  • An example of such a substance is gelatin, and in order to prepare the capsules a known method is used involving the mixing of the catalyst 7B and the gelatin 7C.
  • the thickness of the gelatin coating 7C should be such as to minimise the use of the gelatin.
  • the coating should be as thin as possible whilst performing its indicated function. It has been found that mixing catalyst and gelatin in a ratio of 12 parts catalyst to one part gelatin provides a sufficiently thin yet strong shell or coating 7C for the desired effect to be achieved.
  • Fig. 1C indicates an arrangement similar to Fig. IB, but the microcapsule structure is modified in accordance with a further aspect of the invention which will be described hereinafter, and therefore reference will be made hereinafter to this figure.
  • a supply of lining pipe 10 is delivered to a manhole 15 in a layered condition on a roll 11 or on a pallet, which can include a winching system.
  • lining pipe 10 can be delivered to manhole 15 in a folded pack.
  • An existing pipeline 20 to be relined can have liquid such as water flowing therethrough in the direction of arrow A. If fluids are to continue to flow through existing pipeline 20 during installation of lining pipe 10, pipe 10 should be installed in the direction of fluid flow.
  • Figs . 2A, 2B and 2C illustrate steps of the pull-in installation method in accordance with an embodiment of the invention.
  • a rope 13 is fed from a leading end 18 of lining pipe 10, down manhole 15, through existing pipeline 20 and out through a downstream manhole 16 where it is pulled by a takeup winch 12. Lining pipe 10 is then pulled into position between manholes 15 and 16 as shown in Fig. IB.
  • a sealing ring 17a is provided for securing pipe 10 in position after insertion into existing pipeline 20. Fluid flowing in the direction of arrow A will inflate lining pipe 10.
  • An inflatable or mechanical valve device 21 is positioned at downstream manhole 16 to control fluid pressure and thereby control the inflation of lining pipe 10. During inflation, fluid will back-up in manhole 15 as the pressure within lining pipe 10 builds up.
  • Fig. 3 illustrates an axial transducer ultrasound device 100 for use with lining pipe 10 in accordance with the invention.
  • Ultrasound device 100 includes an axial transducer having a piezoelectric transducer 103 at each end of a titanium cylinder 104. Transducers 103 are connected to a power source by a power cable 101.
  • Device 100 radiates a uniform field of ultrasound radially throughout the water within replacement pipe 10 without attenuation and onto and through replacement pipe 10. Replacement pipe 10 will absorb some of the ultrasound energy by chemical reaction and conversion to heat and the remainder will be transmitted.
  • Axial transducer ultrasound device 100 also includes a plurality of guide springs 102 for correctly positioning device 100 within inflated replacement pipe 10.
  • a multiple transducer ultrasound device 200 is shown in Fig. 4.
  • Multiple transducer device 200 includes a plurality of ultrasound transducers 201.
  • Multiple transducer device 200 can provide larger power although the field pattern may not be as uniform.
  • Another alternative transducer arrangement is to focus the ultrasound field onto a narrow circumferential band by a profiled axial transducer. This can reduce the energy requirements needed for curing the resin. Suitable devices can be obtained from Martin Wlater Ulteraschalltechnic GMBH, Hardtstrasse 13-Postfach 6, Ortsteil Conweiler D-7541 Straubenhardt 5.
  • a modified method of activating the microcapsules there may be two ultrasonic sources which operate at different frequencies. These devices may be pulled through the pipe in sequence, the first serving to rupture the capsules and the second, perhaps running at higher frequency, serving to assist and perhaps accelerate the cure. Details of the invention will be described more fully in the following examples. These examples are presented for purposes of illustration only and are not intended to be construed in a limiting sense.
  • the stability and cure time of a polyester resin (Scott Bader Crystic 491) and two initiators (encapsulated benzoyl peroxide and Trigonox 42S) after irradiation by ultrasound generated from a Sonics Systems 20 kHz horn with a 1.94 cm and a 0.70 cm diameter horn tip were evaluated as follows.
  • Table 1 shows that a steady reduction in gel times were achieved as the concentration of encapsulated benzoyl peroxide was increased from 1 to 4%. Above this concentration, little reduction in gel time was observed. It is believed that when the concentration of encapsulated benzoyl peroxide is increased above about 4%, there is an increase in the resin viscosity which reduces the efficiency at which the cavitation events rupture the initiator capsules.
  • Example 2 shows a preferred range of ultrasonic field intensity as between about 4Wcm ⁇ 2 and 9Wcm"" 2 . At lesser energies, there was not sufficient energy to rupture the initiator capsules. Above this threshold, the horn diameter becomes an important factor, because the larger tip can irradiate a larger proportion of the sample.
  • Example 3 shows that the concentration of co-initiator has little effect on the gel time of the resin.
  • the rate controlling step in the curing reaction is the rate at which the initiator capsules are pondered by ultrasound.
  • the encapsulated initiator can be used to create locate exotherms caused by the polymerization reaction and thus cause a more thermally stable initiator to become effect and thus increase the degree of polymerization.
  • the encapsulation of benzoyl peroxide catalyst effectively prevents interaction between the thermally unstable initiator and the resin into which it is incorporated.
  • cavitation from application of the ultrasonic field ruptures the capsules containing the initiator, the resin system becomes thermally unstable and begins to cure at ambient temperatures.
  • the application of ultrasound does little to increase the average temperature of the resin system. Rather, the ultrasound releases the catalysts and helps initiate the polymerization reaction, which in turn is exothermic, thus generating heat which leads to the exothermic curing reaction.
  • Figs. 5 to 9 and 1C In relation to the aspect of the invention relating to the use in/or adjacent the resin of particles such as magnetisable particles which are susceptible to radiation, reference is now made to Figs. 5 to 9 and 1C.
  • the lining pipe 2X in Figs 5 to 7 is similar to that in Fig. 1 and comprises a layer of fibrous material 3X, e.g. polyester or other felt, that is impregnated with polyester resin or other suitable heat-curable substance and which contains magnetizable matter capable of being caused to heat by a magnetic field.
  • fibrous material 3X e.g. polyester or other felt
  • the magnetisable matter will typically be magnetisable particles which are contained in the resin in much the same manner as the microcapsules 8A are contained the resin in the embodiment of the invention shown in Fig. 1A. Indeed magnetisable particles and microencapsulated catalyst may be included in the resin at the same time.
  • the microcapsules and magnetic particles may be contained in the resin and/or in the fibres and in a particular arrangement the magnetisable or other particles may be contained within the microcapsules themselves as shown in Fig. lC. In this figure the magnetisable particles are indicated by reference M and it will be seen that they are contained both in the catalyst 7B and in the capsule shell 7C.
  • the purpose of these elements is to cause the generation of heat when the elements are subjected to radiation.
  • the catalyst may be used in conjunction with these particles especially if the resin is one which is preferred and which requires a high temperature for initiation of cure.
  • the catalyst may be embodied in microcapsules in which case the generation of heat by the application of the radiation to the particles would be used to break the microencapsulation shells and release the catalyst. It will be appreciated that there are various ways of achieving initiation of the cure of the resin.
  • lining 2X To prevent liquid or other extraeous matter from coming into contact with the above constituents of lining 2X, the latter is clad on one or both sides with sheeting 4X that is impermeable to liquid and/or dust, e.g. polyethylene sheeting.
  • sheeting 4X that is impermeable to liquid and/or dust, e.g. polyethylene sheeting.
  • the magnetizable matter is preferably incorporated in the resin (and/or may be incorporated in the fibres) and may consist of particles M of a suitable ferromagnetic material, e.g. iron filings, ion particles or iron oxide powder such as that sold under the name "Bayferrox" by Bayer.
  • a suitable ferromagnetic material e.g. iron filings, ion particles or iron oxide powder such as that sold under the name "Bayferrox" by Bayer.
  • the magnetizable matter may be added to the fibrous material 3X separately from the resin, and/or may be incorporated in one or both cladding sheets 4X, and/or indeed in the shells of the micro capsules as hereinbefore described.
  • the magnetisable material or the like can be adjacent the resin, as opposed to being in it, and this in fact opens up further possibilities for the use of magnetisable strips or coatings adjacent the resin provided that they will heat up to a sufficient degree under the influence of the radiation applied to cure the resin.
  • Apparatus 10X comprises a core member 11X to the front end of which is secured a wire or cable 12X for drawing the apparatus along a pipe IX. From the rear end portion of core member 11X project a set of radial and rearwardly inclined spacer arms 13X supporting at their outer ends an annulus 14X consisting either of a single ring-like electromagnet or of a ring-like arrangement of electromagnets such as to form, in operation, an unbroken annular magnetic field.
  • the coil(s) of the electromagnet(s) is(are) supplied from the core member 11X with a varying, preferably alternating, current fed along conductors in one or more of arms 13X.
  • the core member 11X is in turn supplied from an external source with current by a conductor associated with the wire or rope 12X.
  • This latter current may be fed directly to the coil(s), if suitable, or, if not, may be appropriately modified by means, not shown, contained in the core member 11X, e.g. to increase the alternations and/or modify the voltage.
  • Such means could for instance include a generator of approx 100 kw - 115 volts DC, and a switching device switching to say 3000 cycles/sec included in the unit in the pipe. Such means being known they will not be described in greater detail here.
  • a magnetic field is generated that penetrates the liner 2X through the adjacent sheeting 4X to magnetize the magnetizable matter in the liner.
  • the magnetizable matter is activated and caused to heat, thereby heating the heat-curable substance in the liner 2X and causing the latter to harden.
  • the rate at which the field should vary will be described in detail below.
  • ET depend on a number of parameters, such as the speed at which apparatus 10X travels along pipe IX and liner 2X, the strength of the field and the distance of the coil(s) from the magnetizable matter.
  • the coil(s) is(are) kept equidistant from the latter by skates 15X or the like of non magnetic material arranged at equal intervals around annulus 14X and engaging the adjacent sheeting 4X of liner 2X.
  • the apparatus 10X can be used without having first to stop or interrupt such a flow. Should the pipe have a relatively low diameter, say 200 mm or so, the amount of space available for the flow of liquid could be too restricted. This possible difficulty can be obviated by the rearward inclination of spacer arms 13X, allowing the annulus 14X to be located behind core member 11X and enabling more space to be provided around the latter.
  • the latter is provided on its forward portion with a further set of radial arms 16X that are fitted at their free ends with skates 17X or the like for engagement with liner 2X.
  • Arms 16X are preferably forwardly inclined so as not to reduce the flow space round core member 11X and provide a better overall weight distribution.
  • the skates 15X and 17X are preferably adjustable in the radial direction as by being telescopically contstructed to enable the apparatus 10X to be adapted to different pipe sizes. They are furthermore preferably resiliently mounted so that they may adjust, during operation of the apparatus, to any slight diameter variations along liner 2X.
  • Pipe IX may be made of some other non-magnetic material e.g. plastic, or be of magnetic material, e.g. iron. In this latter event it would be possible to dispense with the magnetizable matter in liner 2X as the magnetic field created by the electromagnetic means associated with annulus 14X would cause the magnetic material on the inside of the pipe to heat after passing through the liner, the heat generated in the pipe being then transmitted by conduction to the resin in the liner. A similar result can also be achieved with a pipe made of non-magnetic material, internally coated with a layer of magnetizable material.
  • the apparatus 10X described above is intended for round pipes but can of course be modified to work in non round, e.g. oval, pipes by appropriately modifying the shape of the annulus 14X and by relocating arms 13X and 16X and adapting their length.
  • the apparatus can then work in smaller pipes, or a larger core member can be used.
  • the apparatus is preferably made fluid-tight, particularly when it is expected to be used in liquid conveying pipes.
  • suitable water cooling means may be provided that are supplied with water by a tube associated with the wire or cable 12X.
  • the apparatus may of course be modified in a number of other ways to suit particular conditions of operation.
  • E-M electro-magnetic field
  • a crystalline resin additive to produce a thickened pre-preg which is a resin which when first produced is in the nature of a gel and which in due course turns to the consistency of leather, so that it is handlable but sufficiently flexible to be put in position for example when in tube form onto a pipeline or passageway surface.
  • the pre-preg must be subjected to high temperatures e.g. in the order of 110° - 150°C or even higher, but not so high as to cause the resin to decompose.
  • the resin is referred to a pre-preg when it is during its production applied directly to a fibrous sheet structure or has fibres and/or filaments embedded therein.
  • the use of such a pre-preg presents enormous advantages when used with the magnetisable particles or other magnetisable material.
  • the resin will not finally cure until the high temperature curing is applied, and that can only be created by the application of the radiator to the magnetisable particles.
  • the magnetisable particles in the felt fibres prior to felt manufacture ensures even distribution and the felt would be dust free.
  • the fibres may soften at higher temperatures but will set again as they cool.
  • carbon firbre and/or filaments which may act as a reinforcement and be susceptible to heating in a similar way to the iron oxide particles.
  • the said fibres and/or filaments may be such as to form current loops to enhance the heating effect.
  • the filler is particulate material and may be aluminium oxide or titanium oxide.
  • the magnetisable particles or the matter used for the induction heating may be selected or designed to have a low maximum temperature i.e. the temperature at which they lose their property of being susceptible to electro-magnetic induction thus providing a means of preventing the induction particles from over-heating the resin.
  • the transmitted power of the electro - magnetic field will be inversely proportional to the square of the distance from the magnets to the felt, the controlled location of the magnets may be crucial. It should be noted that the electro magnets may or may not have metallic core armatures.
  • the electro-magnetic effect will be proportionally higher at the inside of the felt as compared with the outer side. For example, if the felt is lcm thick and the magnets are 1cm distant, the effect will be lxl v 2 x 2 i.e. 1 to 4. If the magnets are 4 cm distant, the effect will be 4 x 4 v 5 x 5 i.e. 16 to 25. Thus the degree is considerably modified if the distance is increased. However, the power requirement will increase. A compromise solution may be the answer.
  • the speed of passage of the heating unit must be suitable for practical application; an estimate is 0.9 to 1.5 metres per minute.
  • the power feed preferably is by direct current, from the surface vehicle to a switching unit in the pipe.
  • the switching unit will preferably be designed with a flotation chamber, to give a net low weight when immersed.
  • Thermal sensors may be incorporated in the travelling unit, so that the power being supplied may be modified and the rate of travel adjusted, so as to achieve optimum effect.
  • SUBSTITUTE SHEET One form of the travelling unit is shown in Figs. 9 and 10 is proposed as being composed of an inflatable, semi - rigid double-skin plastic envelope 3OX in which are embedded the electro-magnets 32X.
  • the switching unit 34X is located centrally, suspended inside the unit, or it could be external to the inflated unit.
  • the positioning of the draw wires 36X and the power cable 38X is central but may be decided upon after consideration of possible fouling by sewer contents.
  • the wiring to the electro - magnets is internal, i.e. inside the double skin envelope, for protection and to avoid foulding with sewer contents.
  • Electro- magnets could be located in the double skin envelope which may be covered with PTFE, offset at an angle to ensure maximum coverage of the pipe being lined.
  • their form would not be rectangular box, but slightly curved, so as to fit the cylinder in which they are mounted.
  • the envelope 30X preferably is inflated with low-pressure air, and the switching unit 34X (HOvolts DC input) converts the DC input to alternating current at a frequency appropriate for feeding to the individual electro-magnets.
  • the switching unit 34X HOvolts DC input
  • the electro-magnets 32X are maintained at controlled distances from the pipe lining material, as the flexibility of the pneumatic housing 3OX should permit the electro ⁇ magnets 32X to follow the internal surface, even when irregularities are encountered.
  • iron or iron oxide particles are included, loose, in the felt, they may tend to agglomerate, when the electro ⁇ magnetic fields are applied and orientate along the lines of the fields . Incorporating the particles inside the felt fibres may overcome this.
  • the particles may be iron oxide in the resin itself.
  • susceptor or receptor materials which are sheet materials used in the packaging industry for the heating of foodstuffs in microwave ovens.
  • susceptor sheet material may be provided by vacuum deposition of metallic particles such as aluminium particles on plastics material sheet.
  • the sheet can be laminated with a further sheet to isolate the particles but in effect form a sheet heater which is flexible, and this technology can be adapted for the passageway lining technology the subject of the present invention.
  • the metallic particles can be for example vacuum deposited on the fibrous layer of the lining pipe, or can be embodied in a plastic sheet material which is applied to the lining pipe, but in any event will be subject to activation by a microwave radiation source which as described in the said US Patent 4641005 reaches a high temperature in the order of 200°C when subject to microwave radiation. It may be necessary to exercise some control on the maximum temperature to which the particles can be heated by the microwave radiation, in order to match the cure temperature of the resin system which is utilised, but there are also existing patents which are designed to prevent run ⁇ away heating using susceptor materials.
  • the plastic sheets incorporating vacuum deposited metallic particles may be used as the liner sheets of the lining pipe as hereinbefore described, and the susceptor material may be at either side of the lining pipe.
  • a microwave radiation sourse would then be drawn through the pipeline with the lining pipe in place to activate the susceptor material and thereby to raise the temperature of the susceptor material in order to transfer the heat to the resin system in order to activate same.
  • plastics material susceptor film is utilised in the packaging industry, and an example of utilisation in the packaging industry is described in US Patent 4890493 which discloses the use of flexible sheet material for the wrapping of foodstuff items to be cooked.
  • the use of the susceptor material in conjunction with a pre-preg type resin as referred herein is a particularly advantageous arrangement in the matter of lining pipelines or passageways.
  • the resin may include microencapsulated catalyst and other added matter susceptible to radiation, such as the magnetic particles and/or fibres and/or filaments in which magnetic and/or electrical effects can be induced to cause heating of same.
  • ingredients or compounds recited in the singular are intended to include compatible mixtures of such ingredients wherever the sense permits.

Landscapes

  • Lining Or Joining Of Plastics Or The Like (AREA)

Abstract

L'invention se rapporte à un procédé pour produires des articles en résine à partir d'un système de réaction de résine, ce procédé utilisant un matériau résineux non durci ainsi qu'une matière ajoutée activable par exposition à un rayonnement. Dans un premier mode de réalisation, cette matière est constituée par un catalyseur enfermé dans des microcapsules et, en appliquant une énergie ultrasonore, on libère le catalyseur, ce qui déclenche le durcissement de la résine. La matière du catalyseur est insoluble dans l'eau et mise en microcapsules avec de la gélatine. Dans un deuxième mode de réalisation, des particules réagissant à un rayonnement, telles que des particules d'oxyde de fer, sont incorporées dans la résine et sont amenées à s'échauffer par application d'un champ magnétique alternatif qui fait durcir la résine. Ce champ magnétique est généré par un organe électromagnétique annulaire (14X) porté par un noyau (10X) tiré par un câble (12X) à travers le conduit (1X) et le tube (2X). Cette technique s'applique particulièrement bien à des conduits de remplacement, et un procédé pour installer de tels conduits de remplacement dans une canalisation existante consiste à faire durcir la résine en faisant passer un générateur de rayonnement approprié à travers un fluide à l'intérieur du conduit de remplacement gonflé. Le système de la présente invention présente des avantages particulièrement intéressants lors de la réparation de fuites dans des canalisations d'égoût et similaires, dès lors que la présence de liquide en écoulement ou similaire n'affecte pas le rayonnement appliqué.
EP93902407A 1992-01-17 1993-01-18 Systemes de resines durcissables et applications correspondantes Withdrawn EP0621883A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP93902407A EP0621883A1 (fr) 1992-01-17 1993-01-18 Systemes de resines durcissables et applications correspondantes

Applications Claiming Priority (8)

Application Number Priority Date Filing Date Title
EP92810029A EP0551790A1 (fr) 1992-01-17 1992-01-17 Procédé pour le durcissement d'une substance thermodurcissable contenue dans un revêtement de tuyau de même que dispositif et revêtement pour la mise en oeuvre de ce procédé
EP92810029 1992-01-17
US83468392A 1992-02-11 1992-02-11
US834683 1992-02-11
US99097292A 1992-12-15 1992-12-15
US990972 1992-12-15
EP93902407A EP0621883A1 (fr) 1992-01-17 1993-01-18 Systemes de resines durcissables et applications correspondantes
PCT/GB1993/000107 WO1993015131A2 (fr) 1992-01-17 1993-01-18 Systemes de resines durcissables et applications correspondantes

Publications (1)

Publication Number Publication Date
EP0621883A1 true EP0621883A1 (fr) 1994-11-02

Family

ID=27442479

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93902407A Withdrawn EP0621883A1 (fr) 1992-01-17 1993-01-18 Systemes de resines durcissables et applications correspondantes

Country Status (1)

Country Link
EP (1) EP0621883A1 (fr)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9315131A3 *

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