IE20120365A1 - Adhesive composition for brazing elimination and instant sealing - Google Patents

Abstract

A high pressure connection and method for making a high pressure connection. The high pressure connection typically comprises two hollow, tubular members with a cured reaction product of a radiation curable composition therebetween. The radiation curable composition curable composition comprises a reactive component and a photoinitiator. The method includes applying the curable composition to one distal joint portion of a tubular member; sliding one distal joint portion into the other distal joint portion and exposing the assembled portions to radiation sufficient to initiate curing of the composition between the portions at a commercially reasonable speed, wherein cured reaction products of the curable composition maintain the second tubular member distal joint portion within the first tubular member distal joint portion thereby forming the high pressure connection. The method does not use plastic deformation of the first or second distal joint portions after the step of sliding. The method is advantageously useful for making high pressure connections in gas compression systems, refrigeration systems and refrigerated food dispensing systems.

Description

ADHESIVE COMPOSITION FOR BRAZING ELIMINATION AND INSTANT SEALING Field [001] The present disclosure relates generally to new and improved fluid connection systems and methods for their manufacture. In advantageous aspects the present disclosure relates to new and improved high pressure connection systems and methods for their manufacture that can be used in gas compression systems, refrigeration systems and refrigerated food dispensing systems.

Brief Description of Related Technology [002] Refrigeration systems that rely on a refrigerant phase change to provide a temperature differential are used in numerous applications including commercial and residential refrigeration, freezing, air conditioning and heating systems, and food systems that dispense cooled food products. Refrigeration systems typically include a compressor, a condenser, a metering device and an evaporator all fluidly connected and containing a refrigerant. The compressor takes low pressure refrigerant vapor and pressurizes the vapor. Refrigeration compressors can be of the reciprocating piston, screw, rotary, scroll or centrifugal type. The condenser takes high pressure refrigerant vapor from the compressor, removes heat from this vapor and condenses the vapor to a pressurized liquid. The metering device modulates or restricts flow of the liquid refrigerant to the evaporator. Metering devices range from a capillary tube as used in residential refrigerators to a modulating thermostatic expansion valve used in more sophisticated systems. The evaporator allows liquid refrigerant to absorb heat and evaporate to a gas. The refrigeration system can also include accessories such as refrigerant dryers, system access points to check internal pressure and add refrigerant, etc.

[003] The refrigerant is a material that can change between liquid and vapor phases under specified conditions. Refrigerants include the fluorinated hydrocarbon refrigerants such as R-20 (CHCb), R-22 (CHF2CL), R-22B1 (CHBrF2), R-32 (CH2F2), R-125 (CHF2CF3), R-134A (CH2FCF3), R-143A (CH3CF3), R-152A (CH3CHF2), R-404A (a zeotropic mixture of R-125 and R-143A), R-407C (azeotropic mixture of R-32, R-125 and R-134A), R-410A (a zeotropic mixture of R-32 and R-125), R-502 (an azeotropic mixture of R-22 and R-115), R-507 (an azeotropic mixture of R-125 and R-143A), R-1120 (CHC1CC12) and R-C316 (CR/yFg). Refrigerants also 't include non-fluorinated refrigerants such as ammonia (NH3), R-290 (propane), R-600 (butane) and R-600A (isobutene).

[004] Many high pressure connections exist between and among the compressor, condenser, metering device, evaporator, tubing and accessories. To be commercially acceptable for use in a refrigeration system it is advantageous that each connection have one or more properties. For instance, the connections should not leak refrigerant or refrigerant oil for the life of the system. The connections should withstand the internal working pressure and maximum burst pressure of the contained refrigerant without failure. Earlier refrigeration systems had working pressures of about 200 pounds per square inch. However, different refrigerants have come into use in recent times to meet evolving environmental standards and high pressure connections in these new refrigeration systems need to be designed with those different refrigerants and standards in mind. The connections should withstand flexing and vibration without fracture or failure. The connections should be inert to internal environmental conditions such as exposure to refrigerant or refrigerant oil. A connection material that washes off or dissolves during use can undesirably redeposit in or on other parts of the refrigeration system leading to compromises in the integrity if the refrigeration system causing inefficiencies in operation, aesthetic problems and even failures. The connections should be resistant to external environmental conditions such as exposure to cleaning chemicals. The connections should be useful with refrigeration system components and tubing of different sizes and materials. The connections should be useful with refrigeration system components having large gaps, for example about 0.001 inches (0.02 mm) to about 0.08 inches (2mm), between the assembled components. The connections should be fabricated quickly. After assembly the connections should be self supporting and capable of use quickly. Some assembly operations pressurize and start the refrigeration system less than one hour after the connections are formed. The connections should be capable of manufacture by workers with minimal training using inexpensive equipment. It is desirable that the connections can be fabricated without using hazardous materials or hazardous processes. Naturally it is desirable that the connection can be fabricated at a low cost. The connections should also be repairable without special equipment.

[005] Typically, smaller refrigeration systems use two processes to form high pressure connections: high temperature fusion joining processes such as welding or brazing and low temperature mechanical joining processes that rely on swaging or plastic deformation of the joined components. However, despite a long period of use neither of these processes is completely satisfactory for a high pressure connection. High temperature processes require expensive automated equipment or skilled workers. High temperature processes require use of hazardous or flammable fluxes. Only selected brazing filler materials can be used to make the refrigeration system connections. Brazing a high pressure connection having an aluminum member is, at best, difficult and requires specialized equipment and brazing materials. The high temperatures and open flames used in fusion joining processes are dangerous when flammable refrigerants are present. Low temperature swaging processes such as the LOKRING process permanently deform the attached parts. This prevents disassembly of the joined parts and makes subsequent repair of a damaged connection difficult. Swaging processes also add expensive components to the connection and require use of expensive equipment. The swaging components must be selected based on connection diameter, thereby requiring a user to maintain a plurality of connectors for each connection member size or limit the connection sizes used. Workers must be trained to correctly use the swaging equipment and swaging process. Even with training, swaging of parts having large gaps or swaging of small diameter parts is difficult at best. It is not usually possible to form a swaged connection during a field repair.

[006] Threaded pipes are another type of fluid connection that can be useful in some applications such as industrial machinery and industrial plumbing. Tubing used in threaded applications requires heavier walls to allow thread formation. Use of threaded pipe connections for residential or consumer use is limited because heavier pipe is required and because of the cost and effort required to thread the mating pipe connections.

[007] U.S. Patent No. 3,687,019 discloses a two part tube joint construction for a hermetic compressor. This tube joint construction relies on an interference fit between parts, uses a mechanical crimp between the parts and an anaerobic sealant. Even with an interference fit between parts, a mechanical crimp and anaerobic sealant the tube joint construction appears to be limited to an internal pressure of only up to 500 pounds per square inch.

[008] U.S. Patent No. 3,785,025 also discloses a two part tube joint construction for a hermetic compressor. This tube joint construction relies on an interference fit between parts, uses a mechanical crimp between the parts and an anaerobic sealant and suffers from the same internal pressure deficiencies as those in the ‘019 patent.

[009] U.S. Patent No. 6,494,501 discloses a multiple part joint construction including a double wall pipe connector. This pipe connector requires two spaced walls defining a gap between which a tube and sealant is disposed. Such a connector is difficult to form, limited to use with only one tube diameter and adds an additional part and operation to the formation of a tubing connection. [010] Compositions having a cure initiated by exposure to radiation, for example visible or ultraviolet (UV) radiation, are known. However, high pressure connections have overlapping construction with an extended adhesive bonding area between the mated tubing parts as well as adhesive fillets internal and external to the mated tubing parts. The mated tubing parts limit UV radiation exposure to only adhesive in the external area. The inventors have found that some UV curable compositions when used in a high pressure connection cure quickly in this external area (skin over) but may take many hours to cure within the extended, internal bonding area.

[011] Despite the state of the technology, there remains a need for a new type of high pressure connection useful in compressed gas and refrigeration systems.

SUMMARY [012] The present application provides broadiy a method of making a pressurizable connection using a radiation curable composition.

[013] One aspect thereof in a more specific embodiment provides a method of making a high pressure connection. As used herein a high pressure connection is a connection that can retain gas or liquid at a maximum pressure of at least 1,200 pounds per square inch, advantageously a pressure of at least 1,500 pounds per square inch and more advantageously a pressure of at least 2,000 pounds per square inch.

[014] The high pressure connection is advantageously useful in compressed gas systems, refrigeration systems and refrigerated food dispensing systems such as drink dispensers. In one advantageous embodiment the high pressure connection consists essentially of a first distal joint portion, a second distal joint portion and cured reaction products of a radiation curable composition therebetween. As used herein a “high pressure connection consisting essentially of a first distal joint portion, a second distal joint portion and cured reaction products of a radiation ® 3 ® § curable composition” indicates that high pressure connections incorporating other structural elements are not included. Thus, high pressure connections that require other structural elements to form a high pressure connection, for example, weld material, threads or threaded interconnection, a ferrule, a driver ring, a lock ring, a swage ring, plastic deformation of the tubular structures or cured reaction products of epoxy resins alone or polyurethane resins alone are disclaimed in this aspect, [015] The method of this embodiment comprises providing the first distal joint portion. The first distal joint portion is generally tubular and includes a substantially uniform cylindrical outer surface free from threads, a substantially uniform cylindrical inner surface free from threads having an inner diameter defining a bore through the member, and a circumferential end connecting the outer and inner surfaces.

[016] The second distal joint portion is also provided. The second distal joint portion is generally tubular and includes a substantially uniform cylindrical outer surface free from threads and defining an outer diameter smaller than the first distal joint portion inner diameter, a substantially uniform cylindrical inner surface free from threads defining a bore through the member, and a circumferential end connecting the outer and inner surfaces.

[017] The second distal joint portion is slidingly received into the first distal joint portion. The area between the adjacent joint portions is a bond area.

[018] A radiation curable composition is provided. As used herein a radiation curable composition is a composition in which curing is initiated by exposure to radiation. A radiation curable composition may also have a secondary curing mechanism, for example an anaerobic curing mechanism.

[019] The curable composition is applied to the bond area, either before or after assembly ofthe distal joint portions. In variations where the curable composition is applied to the distal joint portions after assembly the curable composition would typically be a low viscosity composition applied adjacent the exposed distal joint region and would flow or wick between the assembled distal joint portions.

[020] In some embodiments a primer composition can optionally be applied to the bond area, either before or after assembly of the distal joint portions and before or concurrently with the curable composition. // y: y ϋ 5 [021] The radiation curable composition is exposed to radiation to cure the adhesive sufficiently to maintain the second distal joint portion within the first distal joint portion. Substantially full curing of the curable composition forms the high pressure connection. Advantageously, there is no plastic deformation of the material comprising the first distal joint portion or the second distal joint portion after the step of sliding. Plastic deformation refers to a permanent change in the shape of an object caused by an applied force.

[022] The composition and method can be used to retain gasses or liquid refrigerant at a maximum pressure greater than 650 pounds per square inch. The composition and method may be useful to retain gasses or liquids at pressures greater than 1,200 pounds per square inch, advantageously at a pressure greater than 1,500 pounds per square inch and more advantageously at a pressure greater than 2,000 pounds per square inch within the system.

[023] The method can be used when the distal joint portions are independently selected from copper, aluminum, steel, coated steel, stainless steel and plastic. The method is advantageous when one distal joint portion is aluminum and the other distal joint portion is independently selected from copper, aluminum, steel, coated steel, stainless steel and plastic.

[024] The method can be used when there is a gap up to about 0.08 inches (2 mm) between the first distal joint portion inner diameter and the second distal joint portion outer diameter.

[025] In some embodiments the high pressure connection is a two part connection. As used herein a two part tube connection includes only the two tubes or members to be joined. Each tube includes one distal joint portion so that the distal joint portion of one tube is disposed within the distal joint portion of the other tube. A two part tube connection does not use fittings or connectors to join the two tubes.

[026] In some embodiments the high pressure connection may be a multiple part connection.

As used herein a multiple part tube connection includes the two tubes or members to be joined and further includes an additional short fitting or short connector. Each tube includes one distal joint portion and the connector includes two distal joint portions. The distal joint portion of each tube is slidingly received within or over the respective distal joint portions of the connector. Typically in multiple part connections the tubes are in end to end relationship and are not disposed within each other. , 3 ® 5 Η Ο ij [027] In some embodiments the high pressure connection is advantageously used in a refrigerated food dispensing system, a refrigeration system, a freezer system, a refrigeratorfreezer, an air conditioner, a heat pump, a residential heating, ventilation and air conditioning (“HVAC”) system, a commercial HVAC system or a transportation HVAC system such as in an automobile, truck, train, airplane, boat, etc. The high pressure connection in a refrigeration system can be part of a refrigerated food dispensing system such as a chilled food dispenser or chilled beverage dispenser. In some embodiments the high pressure connection is advantageously used in a gas compression system such as an air compressor system.

[028] The curable composition advantageously comprises a reactive component and a photoinitiator component. The curable composition can optionally comprise other components. [029] In general, unless otherwise explicitly stated the disclosed materials and processes may be alternately formulated to comprise, consist of, or consist essentially of, any appropriate components, moieties or steps herein disclosed. The disclosed materials and processes may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants, moieties, species and steps used in earlier materials and processes or that are otherwise not necessary to the achievement of the function and/or objective of the present disclosure.

[030] When the word about is used herein it is meant that the amount or condition it modifies can vary some beyond the stated amount so long as the function and/or objective ofthe disclosure are realized. The skilled artisan understands that there is seldom time to fully explore the extent of any area and expects that the disclosed result might extend, at least somewhat, beyond one or more of the disclosed limits. Later, having the benefit of this disclosure application and understanding the embodiments disclosed herein, a person of ordinary skill can, without inventive effort, explore beyond the disclosed limits and, when embodiments are found to be without any unexpected characteristics, those embodiments are within the meaning of the term “about” as used herein. χ 3 ® Β BRIEF DESCRIPTION OF THE DRAWINGS [031] Referring now to the drawings wherein like elements are numbered alike in the several Figures:

[032] Figure 1 is a schematic representation of a refrigeration system.

[033] Figure 2 is an exploded, schematic elevational view of portions of two tubular members forming a two part connection.

[034] Figure 3 is an exploded, schematic, elevational view of portions of two tubular members forming a multiple part connection.

[035] Figure 4 is a schematic, elevational view of one embodiment of high pressure connections comprising portions of two tubular members bonded to a “U” shaped connector.

[036] Figure 5 is a perspective view of a portion of a refrigerator. The arrows illustrate two part, high pressure connections that may be formed according to the method of this disclosure DETAILED DESCRIPTION [037] A fluid connection and method useful to prepare the fluid connection is provided. In one embodiment the fluid connection can advantageously be a high pressure connection. The high pressure connection is useful for a number of applications. However, refrigeration system connections have unique and stringent requirements not all of which are necessary or present in other types of fluid connections. The disclosed high pressure connection is advantageously useful in preparing a connection in a refrigeration system impermeable to refrigerants and refrigerant oils. For clarity refrigeration systems are described herein, however as noted refrigeration systems are not the only systems that may benefit from the advantages of the subject application. [038] With reference to Figure 1, refrigeration systems include a compressor 10, a condenser 12, a metering device 14 and an evaporator 16 all fluidly connected by tubing and containing a refrigerant. There are a plurality of high pressure connections (not shown for clarity) between, and within, the tubing, compressor, condenser, metering device, evaporator and any accessories. The connections are preferably two part connections as exemplified in Figure 2 although multiple part connections as exemplified in Figure 3 are known in refrigeration systems. Each two part connection typically comprises two hollow, tubular members 22, 24 with a cured reaction product of a radiation curable composition therebetween.

[039] Each tubular hollow member is independently comprised of a material, for example copper, aluminum, steel, coated steel, stainless steel and plastic. Coated steel includes a steel member coated with another material, for example a steel member coated with copper plating, in one embodiment one tubular connector is comprised of aluminum and the other tubular connector is comprised of copper. In one embodiment both tubular connectors are comprised of aluminum. In one embodiment at least one of the tubular members is plastic.

[040] Each tubular member typically has a length many times, for example five to ten times or more, its diameter. One tubular member 22 has a distal joint portion 26 including a substantially uniform cylindrical outer surface 28 free from threads, a substantially uniform cylindrical inner mating surface 30 free from threads having an inner diameter and a circumferential end 32 connecting the outer 28 and inner 30 surfaces. The inner diameter does not require any optional chamfer or expansion of the distal joint portion 26 adjacent the end 32. The other tubular member 24 has a distal joint portion 36 including a substantially uniform cylindrical outer mating surface 38 free from threads and defining an outer diameter, a substantially uniform cylindrical inner surface 40 free from threads and a circumferential end 42 connecting the outer 38 and inner 40 surfaces. The outer diameter does not require any optional chamfer or expansion of the distal joint portion 36 adjacent the end 42. The inner diameter of distal joint portion 26 is larger than the outer diameter of distal joint portion 36 to allow distal joint portion 36 to be disposed within distal joint portion 26, Since the members 22, 24 are generally formed without machining, e.g. from purchased tubing or swaged tubing, each member can have a considerable range of distal joint portion diameters. Given this range of diameters the gap between a complementary set of members 22, 24 can be in the range of about 0.001 inches (0.02 mm) to about 0.08 inches (2mm). No interference or press fit between the inner diameter of distal joint portion 26 and the outer diameter of distal joint portion 36 is required to form a high pressure connection.

[041] Surprisingly, it has been found that distal joint portions bonded by the cured reaction product of a radiation curable composition can form a leakproof connection that can maintain integrity at pressures of about 650 pounds per square inch or more, even between distal joint portions having gaps up to 0.08 inches. Use of a primer composition with the radiation curable composition is not required to achieve connection integrity although a primer composition may optionally be used in some variations.

IE 12 6 3 6 5 [042] To prepare a high pressure connection complementary members 22, 24 are provided. The mating surfaces 30, 38 should be clean and free of contamination. Abrasion of one or both mating surfaces may be advantageous. A primer composition may optionally be applied to the mating surface 30, 38 of one distal joint portion 26, 36 respectively. A curable composition is applied to a mating surface, typically of the other distal joint portion. The smaller diameter distal joint portion 36 is slidingly disposed within the larger diameter distal joint portion 26. The bond area is the overlapping area between ends 32 and 42 in the assembly. Some rotation of the distal joint portions may be beneficial to distribute the curable composition and any optional primer around the entirety of the mating surfaces but is not required.

[043] The members 22, 24 are held in position and the curable composition near the exterior intersection of the distal joint portions is exposed to radiation, typicaliy for less than about 60 seconds, advantageously less than about 40 seconds and desirably less than about 20 seconds to at least partially cure the composition. The at least partially cured composition has sufficient strength to maintain the second tubular member distal joint portion within the first tubular member distal joint portion during subsequent handling. Typically, a radiation source such as a light wand or lamp is used to initiate cure of the curable composition. Once the composition is exposed to radiation, curing will progress from the radiation exposed exterior composition into composition within the bond area and between ends 32. 42. The composition may further cure for a short time, for example anaerobically curing within the connection, thereby forming the high pressure connection between the ends 32, 42 of the distal joint portions. Typical cure times at room temperature will be less than 5 minutes and advantageously less than 3 minutes before the connection can be pressurized for use.

[044] The exterior surface 28 of distal joint portion 26 defines an exterior surface of the high pressure connection and the interior surface 40 of distal joint portion 36 defines an interior surface of the high pressure connection. Plastic deformation in the material of either distal joint portion 26, 36 after disposition of the smaller diameter distal joint portion 36 within the larger diameter distal joint portion 26 is advantageously avoided.

[045] In another embodiment a multiple part connection typically comprises two hollow, tubular members 46, 50 and a hollow connector 48. One tubular member 46 has a distal joint portion 52 including a substantially uniform cylindrical outer surface 54 free from threads, a JE 120365 substantially uniform cylindrical inner surface 56 free from threads having an inner diameter and a circumferential end 58 connecting the outer 54 and inner 56 surfaces. The other tubular member 50 has a distal joint portion 62 including a substantially uniform cylindrical outer surface 64 free from threads and defining an outer diameter, a substantially uniform cylindrical inner surface 66 free from threads and a circumferential end 68 connecting the outer 64 and inner 66 surfaces. The connector 48 has two distal joint portions 72, 74, Distal joint portion 72 includes an outer surface 76 free from threads, an inner surface 78 free from threads and a circumferential end 80. Distal joint portion 74 includes an outer surface 84 free from threads, an inner surface 86 free from threads and a circumferentiai end 88. The connector 48 is short, for example with a typical length less than five to ten times its diameter.

[046] The inner diameter of distal joint portions 72 and 74 is larger than the outer diameter of distal joint portions 52 and 62 to allow distal joint portions 52 and 62 to be disposed within member 48. Since the members 46, 48, 50 are generally formed without machining, e.g, from purchased tubing or swaged tubing, each member can have a considerable range of distal joint portion diameters. Given this range of diameters the gap between a complementary set of members 46, 48 and 48, 50 can be in the range of about 0.001 inches (0.02 mm) to about 0.08 inches (2 mm). In other embodiments the connector 48 is sized to fit within distal joint portions 52, 62.

[047] To prepare a high pressure connection complementary members 46, 48 are provided. The mating surfaces 54, 78 should be clean and free of contamination. Abrasion of one or both mating surfaces may be advantageous. A primer composition may optionally be applied to one mating surface 54 or 78 of one distal joint portion 46, 48 respectively. A curable composition is applied to a mating surface, typically of the other of the distal joint portion. The smaller diameter distal joint portion is slidingly disposed within the larger diameter distal joint portion. Some rotation of the distal joint portions may be beneficial to distribute the curable composition and any optional primer around the entirety of the mating surfaces but is not required. The members 46, 48 are held in position and the curable composition near the exterior intersection of the distal joint portions is exposed to radiation, typically for less than about 60 seconds, advantageously less than about 40 seconds and desirably less than about 20 seconds to at least partially cure the composition. The at least partially cured the composition has sufficient strength to maintain the second tubular member distal joint portion within the first tubular member distai joint portion during subsequent handling. Once the composition is exposed to radiation, curing will progress from the radiation exposed exterior composition into composition within the connection and between the distal joint portions. The composition may further cure for a short time, for example anaerobically curing within the connection, thereby forming the high pressure connection between the ends 58, 80 of the distal joint portions 52, 72. Typical cure times at room temperature will be less than 5 minutes and advantageously less than 3 minutes before the connection can be pressurized for use. Distal joint portions 62 and 74 are processed in the same manner to form a second high pressure connection between the ends 88, 68 of distal joint portions 74, 62.

[048] Plastic deformation in the material of any distal joint portion after disposition of the smaller diameter distal joint portions within the larger diameter distal joint portions is advantageously avoided. The connector may be straight as shown in Figure 3 or otherwise shaped such as a “U” shaped return bend, exemplified in Figure 4, useful to fluidly connect condenser tubes.

[049] The connector distal portions may have a smaller diameter than the corresponding tubular member distal portions so that the connector distal portions are disposed within the tubular member distal portions. Similarly, while the method is described with reference to the tubular connectors most often used, connectors of other shapes are possible.

[050] In some applications it may be desirable to apply the curable composition and, optionally, the primer composition, to the distal joint portions after their assembly. For example, refrigeration capillary tubes have distal joint portions defining a very small diameter. Applying a non-flowable primer composition to one distal joint portion and a non-flowable curable composition to the other distal joint portion prior to assembly may increase the possibility that one or both of the compositions is introduced into the connection interior during assembly. To lessen this possibility the curable composition can be applied to the distal joint portions after the second distal joint portion is slidingly received into the first distal joint portion. Thus the distal joint portions can be assembled and the curable composition can be applied to the assembled distal joint portions. The primer composition, if used, can be applied to the assembled joint portions sequentially or concurrently with the curable composition. In concurrent application it may be advantageous to apply the primer composition and curable composition to different portions of the IB 12 0 3 6 5 assembly. These variations are advantageously useful with lower viscosity compositions that can wick or flow between the adjacent distal joint portions in the assembly. Alternatively, a curable composition can be applied to one distal joint portion, the distal joint portions can be assembled and the primer composition can be applied to the assembled distal joint portions.

[051] In some applications it may be desirable to apply the primer composition and the curable composition as separate beads to the same distal joint portion. Each composition remains separated on the distal joint portion. The separated beads are mixed when the distal joint portions are assembled.

[052] It may also be useful to prepare a connection comprising multiple, male distal joint portions in a single female distal joint portion using the above methods.

[053] The curable composition comprises a reactive component and a photoinitiator. Some embodiments can include one or more of an initiator, an accelerator; a stabilizer; a diluent; a thickener, a polymer matrix, a plasticizer, a pigment, a dye or a filler. Other agents known in the formulation of adhesives can be employed in any reasonable manner to produce known functional characteristics, providing they do not significantly interfere with the ability of the composition to form a bond suitable for a fluid connection.

[054] The reactive component is a material that will react or cure to form reaction products that bond the fluid connection. One useful class of materials for a reactive component are acrylates, for example the poly- and mono-functional (meth)acrylate esters. (Meth)acrylate esters include both acrylic esters and methacrylic esters. Some useful (meth)acrylic esters have the general structure CH2=C(R)COORi, where R is H, CH3, C2H5 or halogen, such as Cl, and R1 is C|..g mono- or bicycloalkyl, a 3 to 8-membered heterocyclic radical with a maximum of two oxygen atoms in the heterocycle, H, alkyl, hydroxyalky] or aminoalkyl where the alkyl portion is straight or branched carbon atom chain.

[055] Some exemplary monofunctional polymerizable acrylate ester monomers include hydroxypropyl methacrylate, 2-hydroxyethyl methacrylate, methyl methacrylate, tetrahydro furfuryl methacrylate, cyclohexyl methacrylate, 2-aminopropyl methacrylate and the corresponding derivatives and acrylates. Some exemplary polyfunctional monomers include polyethylene glycol dimethacrylate and dipropylene glycol dimethacrylate.

[056] Other useful acrylate materials include those which fall within the structure: 120355 Ο (I I R3 -(CH2) ll C..-.-Czz CH, I R3 where R2 may be selected from hydrogen, alkyl of 1 to about 4 carbon atoms, hydroxyalkyl of 1 to about 4 carbon atoms or ---H2C—O—C—C=CH2 .

R3 R3 may be selected from hydrogen, halogen, and alkyl of 1 to about 4 carbon atoms and Cj. 8 mono- or bicycloalkyi, a 3 to 8 membered heterocyclic radical with a maximum of 2 oxygen atoms in the ring; R4 may be selected from hydrogen, hydroxy and O —h2c—o—c—c =ch2 · m is an integer equal to at least 1, e.g., from 1 to about 8 or higher, for instance from 1 to about 4; n is an integer equal to at least 1, e.g.. 1 to about 20 or more; and v is 0 or 1.

[057] Other useful acrylate materials are those selected from urethane acrylates within the general structure: (CH2-CR5-CO-O-R6-O-CO-NH)2R7 where R5 is H, CH3, C2H5 or halogen, such as Cl; R6 is (i) a Ci.g hydroxyalkylene or aminoalkylene group, (ii) a C]-6 alklamino-Cj-s alkylene, a hydroxyphenylene, aminophenylene, hydroxynaphthalene or amino-naphthalene optionally substituted by a C1.3 alkyl, C].3 alkylamino or di-Ci-3 alkylamino group; and R7 is C2.2o alkylene, alkenylene or cycloalkyiene, Cmo arylene, alkarylene, aralkarylene, alkyloxyalkylene or aryloxyarylene optionally substituted by 1-4 halogen atoms or by 1-3 amino or mono- or di-Ci.3 alkylamino or C1.3 alkoxy groups; or acrylates within the general structure; (CH2=CR5-COO-R6-OCONHR7-NHCOX-)nRs where R5, R6, and R7 are as given above; Rs is a non-functional residue of a polyamine or a polhydric alcohol having at least n primary or secondary amino or hydroxy groups respectively; X is O or NR9s where R9 is H or a C1.7 alkyl group; and n is an integer from 2 to 20.

[058] Other useful urethane acrylates can be selected from reaction products of (meth)acryiated Ci-2o alcohols and a di- or poly-isocyanate such as toluene diisocyanate (TDI), methylenebis(phenyl isocyanate) (MDI), hexamethylene diisocyanate (HDI), naphthalene diisocyanate (NDI), methylene bis-cyclohexylisocyanate (HMDI), isophorone diisocyanate (1PDI), HDI biuret and HDI isocyanurate.

[059] Other useful acrylates can be selected from the class of the acrylate, methacrylate and glycidyl methacrylate esters of bisphenol A. Particularly useful are ethoxylated bisphenol-Adimethacrylate (EBIPMA).

[060] Other useful acrylates include those which are exemplified but not restricted to the following materials: di-, tri-, and tetra-ethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polyethylene glycol dimethacrylate, di(pentamethylene glycol) dimethacrylate, tetraethylene glycol diacrylate, tetraethylene glycol di(chloroacrylate), diglycerol diacrylate, diglycerol tetramethacrylate, tetramethylene dimethacrylate, ethylene dimethacrylate, neopentyl glycol diacrylate and trimethylol propane triacrylate.

[061] The reactive component need not be in the pure state, but may comprise commercial grades in which inhibitors or stabilizers, such as polyhydric phenols, quinones, and the like are included. These materials function as free radical inhibitors to prevent premature polymerization of the reactive component. It is also within the scope of the present disclosure to obtain modified characteristics for the cured composition by utilization of one or more monomers either from those listed above or additional additives such as unsaturated monomers, including unsaturated hydrocarbons and unsaturated esters.

[062] Mixtures or copolymers of any of the above-mentioned reactive components can be employed. The reactive component can be present in amounts from about 10% to about 99.9% by weight of the curable composition, for example from about 70% to about 90% by weight of the curable composition.

[063] The compositions are cured by transmitting energy effective to activate the photoinitiator to the composition. Typicalfy the photoinitiator will utilize energy from the transmitted energy to induce a chemical reaction releasing free radicals. Surprisingly all photoinitiators are not capable of producing a bond suitable for use in a fluid connection. Many photoinitiators will cure the reactive component at the exterior intersection of the connection but will not cure the reactive component between the joint portions or within the interior of the connection in a commercially reasonable time. Naturally, the fluid connection will not be suitable for use until the reactive component cures.

[064] One photoinitiator useful for curing the disclosed compositions are phosphine compounds and phosphine oxide compounds such as acylphosphine oxide compounds. Phosphine oxides themselves can initiate free radical polymerization of the reactive component under ultraviolet (UV) and/or visible irradiation generated by a handheld wand. Phosphine oxide photoinitiators can advantageously provide a depth of cure greater then available from other types of photoinitiators. Exemplary materials are diphenyl (2,4,6-trimethylbenzoyl)-phosphine oxide (monoacyl phosphine oxide or MAPO) and phosphine oxide, phenyl bis (2,4,6-trimethylbenzoyi) (bis acyl phosphine oxide or BAPO). monoacyl phosphine oxide (MAPO) 1£ 12®355 bis acyl phosphine oxide (BAPO) [065] Commercially available phosphine oxides include, but are not limited to, CGI 403, Darocure TPO and Irgacure 819 available from Ciba Specialty Chemicals, Basel Switzerland; and LUCIRJN LR8893X available from BASF Corp,, Charlotte NC. Combinations of photoinitiators can be used.

[066] Typically, the photoinitiator will be employed in an amount of about 0.01 % to about 20 %, suitably about 0.1 % to about 10 % and advantageously about 0.5 % to about 5 % by weight of the composition.

[067] The curable composition can optionally include an initiator component useful for initiating curing of the reactive component in the absence of air. Included within this category are the anaerobically curing, ambient temperature initiator systems which are weii known in the art of curable (meth)acrylate compositions. Initiators include the hydroperoxy polymerization initiators and most preferabiy the organic hydroperoxide initiators having the formula ROOH, where R generally is a hydrocarbon radical containing up to about 18 carbons, desirably an alkyl, aryl or arylalkyl radical containing up to about 12 carbon atoms. Typical examples of such hydroperoxides include t-butyl hydroperoxide, p-methane hydroperoxide, diisopropylbenzene hydroperoxide, cumene hydroperoxide, methylethylketone hydroperoxide as well as hydroperoxides formed by the oxygenation of various other hydrocarbons such as methyibutene, cetane and cyclohexane. Other peroxy initiators such as hydrogen peroxide or materials such as organic peroxides or peresters which hydrolyze or decompose to form hydroperoxides may also be employed. Combinations of Initiators can also be used. Typically, the initiator component will IE ti A ω « s be employed in an amount of about 0.1% to about 4%, suitably about 0.75% to about 2.5% by weight of the composition.

[068] In one embodiment the curable composition comprises about 70 % to about 90 % by weight of a (meth)acrylate component; about 0.75 % by weight to about 2.5 % by weight of an anaerobic cure inducing component; and about 1 % by weight to about 5 % by weight of a photoinitiator component. As used herein all percentages are by weight of the curable composition.

[069] The curable composition can optionally include an accelerator component, particularly if the composition includes an anaerobic curing initiator. Typical accelerators include amines, amine oxides, sulfonamides, metal sources, acids and/or triazines, for example, ethanol amine, diethanol amine, triethanol amine, N,N dimethyl aniline, benzene sulphonimide, cyclohexy! amine, triethyl amine, butyl amine, saccharin, N,N-diethyl-p-toluidine, N,N-dimethyl-o-toluidine, acetyl phenylhydrazine, maleic acid and the like. Of course, other materials known to induce anaerobic cure may also be included or substituted therefore. See e.g., U.S, Pat. No. 3,218,305 (Krieble), U.S. Pat. No. 4,180,640 (Melody), U.S. Pat. No. 4,287,330 (Rich) and U.S. Pat. No. 4,321,349 (Rich). Typically, accelerators will be employed in an amount of 0.1 to 5%, suitably 0.5 to 3% by weight of the composition.

[070] The curable composition can optionally include a polymeric matrix miscible or otherwise compatible with the reactive component. The matrix material may be present in an amount sufficient to render the curable composition self supporting, i.e. non-flowable at temperatures of at least about 70°F (21 °C), and up to about I60°F (71 °C). The polymeric matrix and polymerizable component readily form a stable mixture or combination without phase separation of component parts. Some useful matrix materials are disclosed in U.S. Patent No. 7,144,956 (Attarwala et al.), the contents of which are incorporated herein by reference.

[071] The curable composition can optionally include known additives to improve hot strength and heat resistance properties of the cured reactions products. Some examples of such additives include tri-allyl cyanurate; N,N' meta-Phenylen bis maleimide and other maleimides.

[072] The curable composition can optionally include filler. Such fillers may be selected from a wide variety of materials, including calcium carbonate, organic tin and zinc compounds and aluminum oxide, hydrated alumina and silica, etc. Such fillers can optionally be present in any useful amount, and desirably in an amount of from about 0.1 % to about 20 % by weight of curable composition and desirably about 0.1 % to about 10 % by weight of the composition.

[073] The curable composition can optionally comprise a toughening agent component to decrease brittleness and increase toughness of the cured bond as compared to a bond formed by cured reaction products of the same curable composition without the toughening agent component.

[074] Examples of some useful toughening agents include elastomeric rubbers; elastomeric polymers; liquid elastomers; polyesters; acrylic rubbers; butadiene/acrylonitrile rubber; Buna rubber; polyisobutylene; polyisoprene; natural rubber; synthetic rubber such as styrene/butadiene rubber (SBR); polyurethane polymers; ethylene-vinyl acetate polymers; fluorinated rubbers; isoprene-acrylonitrile polymers; chlorosulfonated polyethylenes; homopoiymers of polyvinyl acetate; block copolymers; core-shell rubber particles, and mixtures thereof. The choice of the toughening agent component will, to a large degree, dictate various properties and characteristics of the primer composition and ultimately various properties and characteristics of cured reaction products of the adhesive composition.

[075] The form of the toughening agent will depend on the materiai chosen and can include particles, nanopartieles, core-shell particles having layers of different hardnesses, liquids, solutions and discrete phases.

[076] Some useful elastomeric polymer toughening agents may be characterized as one having a tensile strength at break of greater than 1500 psi (10342 kPa), preferably greater than 2000 psi (13790 kPa), and an elongation at break of greater than 100%, preferably greater than 200%, The toughening polymer wili typically, but not always, be a block copolymer, including terpolymer, with a Tg of one block segment below -20 °C.

[077] it is effective to use elastomers whose molecular weight averages more than about 100,000, but any molecular weight greater than 5,000 would be expected to effect an improvement. As a principle of general guidance, the molecular weight should be high enough to produce toughening in the subsequently applied and cured composition but not so high that the curable composition is stringy and difficult to use. It is also best to choose an elastomer whose Mooney viscosity (ML(l+4)) is between 20 and about 60, and whose glass transition temperature ί£ 1 2 a 3 δ s (Tg) is 15 °C or iess. These specific limitations are not absolute and various elastomers which do not fall within them may be useful.

[078] The acrylic rubber toughening agents may be selected from a wide range of suitable materials. Most frequently these rubbers are either: (i) homopolymers of alkyl esters of acrylic acid; (ii) copolymers of another polymerizable monomer with an alkyl ester of acrylic acid or with an alkoxy ester of acrylic acid; (iii) copolymers of alkyl esters of acrylic acid with each other; (iv) copolymers of multiple alkoxy esters of acrylic acid with each other; or (v) mixtures of any of the above (i)-(iv), Other unsaturated monomers which may be copolymerized with the alkyl and alkoxy acrylic esters include dienes, reactive halogen-containing unsaturated compounds and other acrylic monomers such as acrylamides. The acrylic rubbers may also include (meth)acrylic acid esters in limited amounts, suitably copolymerized with an acrylate ester or with a lower alkene.

[079] The block copolymer toughening agents can include, for example, an A-B-A block copolymer wherein the A block is polymerized segment of styrene, alpha-methyl styrene, t-butyl styrene, or other ring alkylated styrene, acrylonitrile, methyl methacrylate, or a mixture of some or all of the above and the B block is an elastomeric segment having a low Tg such as that derived from a conjugated diene or copolymer thereof such as butadiene or is an ethylene-propylene polymer. Commercially available examples include EUROPRENE SOL Τ 193 A available from Enichem Elastomers Americas, Inc. and Kraton SBR block copolymer available from Kraton Polymers LLC, Houston, TX.

[080] The polyurethane polymer toughening agents can include, for example, materials such as the MILLATEiANE polymers available from TSE Industries.

[081] Useful the toughening agents can include, for example, elastomeric materials described in U.S. Pat. No. 3,496,250 (Czerwinski); U.S. Pat. No. 3,655,825 (Souder et al); U.S. Pat. No. 3,668,274 (Owens et al); U.S. Pat. No. 3,864,426 (Salensky); U.S. Pat. No. 4,440,910 (O’Connor) and U.S. Pat. No. 5,932,638 (Righettini et al), the contents of each of which is herein incorporated by reference. Useful commercially available toughening agents include those marketed under the tradename HYCAR, commercially available from The Lubrizol Corporation; VAMAC ethylene acrylic elastomers such as VAMAC G, VAMAC VCS, VAMAC VMX and VAMAC VCD, all commercially available from DuPont; BLENDEX BTA III F, ACRYLOID KM 680, ACRYLOID IE 12 0 3 6 5 KM 653, ACRYLOID KM 611, and ACRYLOID KM 330 copolymers, all commercially available from Rohm and Haas Company, BLENDEX 101 copolymer, commercially available from Borg-Warner Corp., METABLEN C 223 copolymer, commercially available from Μ & T Chemicals, Inc., and KANE Ace-B copolymer, commercially available from Kaneka USA.

[082] Liquid elastomer toughening agents can include, for example, the liquid olefrnicterminated elastomers as described in U.S. Pat. No, 4,223,115 (Zalucha et al); U.S. Pat. No. 4,452,944 (Dawdy); U.S. Pat. No. 4,769,419 (Dawdy); U.S. Pat. No. 5,641,834 (Abbey et al), U.S. Pat. No. 5,710,235 (Abbey et al) and U.S. Pat. No. 5,932,638 (Righettini et al), the content of each of which is herein incorporated by reference.

[083] Useful the toughening agents can include, for example, a combination of low molecular weight and high molecular weight toughening agents such as described in U.S. Pat, No. 6,225,408 (Huang et al), the content of which is herein incorporated by reference.

[084] Useful the toughening agents can include, for example, core-shell particles. Core-shell particles have layers of differing harnesses, for example a hard shell formed over a rubbery core. The core can be comprised of a polymeric material having elastomeric or rubbery properties (i.e., a glass transition temperature less than about 0°C, e.g., less than about -30°C) surrounded by a shell comprised of a non-elastomeric polymeric material (i.e., a thermoplastic or thermoset/crosslinked polymer having a glass transition temperature greater than ambient temperatures, e.g., greater than about 50°C). For example, the core may be formed predominantly from feed stocks of polybutadiene, polyacrylate, polybutadiene/acrylonitrile mixture, polyols and/or polysiloxanes or any other monomers that give a low glass transition temperature. Other rubbery polymers may also be suitably for use in the core, including polybutyl acryl ate or poiysiloxane elastomer (e.g., polydimethylsiloxane, particularly crosslinked polydimethylsiloxane), The shell may be formed predominantly from feed stocks of (meth)acrylates (e.g., methyl methacrylate); vinyl aromatic monomers (e.g., styrene); vinyl cyanides (e.g., acrylonitrile); unsaturated acids and anhydrides (e.g., acrylic acid); (meth)acrylamides; and the like having a suitably high glass transition temperature.

[085] The core-shell particle may be comprised of more than two layers (e.g., a central core of one rubbery material may be surrounded by a second core of a different rubbery material or the rubbery core may be surrounded by two shells of different composition or the rubber particle may ΓΕ 1 20 3 6 5 have the structure soft core, hard shell, soft shell, hard shell). In one embodiment the core-shell particles used are comprised of a core and at least two concentric shells having different chemical compositions and/or properties. Either the core or the shell or both the core and the shelf may be crosslinked (e.g., ionically or covalently). The shell may be grafted onto the core. The polymer comprising the shell may bear one or more different types of functional groups (e.g., epoxy groups) that are capable of interacting with other components of the primer composition or with other components of a curable composition.

[086] For instance, the core may be formed predominantly from feed stocks of polybutadiene, polyacrylate, polybutadiene/acrylonitrile mixture, polyols and/or polysiloxanes or any other monomers that give a low glass transition temperature. The outer shells may be formed predominantly from feed stocks of polymethylmethacrylate, polystyrene or polyvinyl chloride or any other monomers that give a higher glass transition temperature.

[087] Typically, the core will comprise from about 50 to about 95 percent by weight of the core-shell particle while the shell will comprise from about 5 to about 50 percent by weight of the core-shell particle.

[088] Typically, the core-shell particles are on the nano scale size. Core-shell particles may have a particle size distribution where at least 90% of the particles have a particle size in the range of in the range of about 3 nm to about 1,000 nm and advantageously a particle size distribution where at least 90% of the particles have a particle size in the range of 3 nm to 500 nm. The coreshell particles have an average diameter of less than about 500 nm, such as less than about 200 nm, desirably in the range of 25 to 100 nm.

[089] Methods of preparing core-shell particle are well-known in the art and are described, for example, in U.S. Patent Nos. 4,419,496; 4,778,851; 5,981,659; 6,111,015; 6,147,142; and 6,180,693, each of which is incorporated herein by reference in its entirety. Core-shell particles are commercially available. Some commercially available core-shell particles include CLEARSTRENGHT and DURASTRENGTH particles, available from Arkema Inc.; KM330 and KM323B, all-acrylic copolymer particles, available from Rohm and Haas; Kureha Paraloid EXL2655 particles comprising butadiene-alkyl methacrylate-styrene copolymers, available from Kureha Chemical Industry Co.; Staphyloid AC-3355 and TR-2122 particles comprising acrylate22 J£ 1 2 0 3 6 5 methacrylate copolymers, available from Takeda Chemicals Industry Co.; Paraloid EXL series particles available from Rohm & Haas Co.

[090] Core-shell particles may be prepared as a masterbatch where the particles are dispersed in a matrix. Methods of preparing such masterbatches are described in more detail in U.S. Patent No. 4,778,851 and U.S. Patent Publication No. 2007/0027233, each of which is incorporated herein by reference in its entirety. Generally, an aqueous mixture comprising core-shell particles may be brought into contact with an organic medium having partial solubility in water and then with another organic medium having lower partial solubility in water than the first organic medium to separate the water and to provide a dispersion of the rubber particles in the second organic medium. This dispersion may then be mixed with the desired matrix, for example epoxy resin(s), and volatile substances removed by distillation or the like to provide the masterbatch. Masterbatch dispersions of core-shell particles in an epoxy resin matrix are commercially available. Some commercially available masterbatches of core-shell particles include the MX series available from Kaneka USA and GENIOPERL available from Wacker Chemie GmbH, Germany.

[091] The amount of toughening agent component can be varied to suit particular applications.

The lower level will be that level which provides a desired decrease in brittleness and increase in toughness of the cured reaction products of the curable composition. The upper level of toughening agent component will be set by considerations of cost and by increase in viscosity. The concentration range of toughening agent component can be from about 0.1 % to about 20 % or more by weight of curable composition, for example from about 0.1 % to about 10 % by weight of curable composition.

[092] The curable composition can optionally comprise a plasticizer to aid in providing flexibility to the adhesive joint formed when the adhesive is cured. Generally, plasticizers useful with anaerobic curing (meth)acrylate compositions will also be useful in the present composition. Some useful plasticizers include non-reactive plasticizers, such as the polyester glycol, tetraethylene glycol di-2-ethyl hexoate; polymeric plasticizer, such as one available commercially under the tradename UNIFLEX 300 from Unicamp Corporation, Jacksonville, Fla, UNIFLEX 300 is a medium molecular weight polymeric plasticizer (made from hexanedioic acid and polymer with 1,4-butane diol and 1,2-propane diol), which is liquid at 25°C whose viscosity at JE 1 2 0 3 6 5 that temperature is 3300 cps. Polyester plasticizers such as those set forth in U.S. Pat. No. 3,794,610 (Bachmann), the disclosure of which is hereby expressly incorporated herein by reference, can also be used.

[093] The curable composition can optionally include one or more composition modifiers such as diluents including reactive diluents, moisture scavengers, free radical scavengers, defoamers, viscosity modifiers, pigments, coloring agents, fluorescent material, stabilizers, and other such additives in amounts suitable to achieve their intended purpose. Typically, composition modifiers will comprise less than about 20 % by weight of the curable composition.

[094] The curable composition in the uncured state can have a range of viscosities, for example about 10 cps to about 1000000 cps, depending on application. Lower viscosities are useful in applications where a more mobile composition is desired while higher viscosities are useful in applications where less flow is desired. In addition, the composition in the cured state should be flexible/tough so as to absorb vibration that is present in a refrigeration system. The composition must also have good adhesive properties to maintain fluid connection integrity under internal pressures expected in the application.

[095] Preparation of the curable composition can be achieved by simple admixture of the preselected materials with mixing to achieve a substantially homogeneous mixture. The composition should be shielded from radiation during preparation to lessen activation of the photoinitiator. If present, no premelting of the polymeric matrix is necessary and the polymeric matrix can be in either the liquid or solid form prior to incorporation thereof.

[096] The curable compositions can be cured by transmitting energy to the composition which is effective to activate the photoinitiator. Desirably, the radiation used to cure the composition has a wavelength from about 200 nm to about 1,000 nm. Useful radiation in connection with the present composition and method includes ultraviolet light, visible light, and combinations thereof. Useful ultraviolet light (UV) includes, but is not limited to, UVA (about 320 nm to about 410 nm), UVB (about 290 nm to about 320 nm), UVC (about 220 nm to about 290 nm) and combinations thereof. Useful visible light includes, but is not limited to, blue light, green light, and combinations thereof. Such useful visible light has a wavelength from about 450 nm to about 550 nm.

II 1 2 Ο 3 6 5 [097] Irradiation of substrates treated in accordance with the practice of the invention can be achieved by the use of UV lamps such as mercury arc lamps (high, medium and low pressure), xenon arc lamps, high intensity halogen-tungsten arc lamps, microwave driven arc lamps and lasers. Useful equipment for transmitting energy to the curable composition include the Indigo and Zeta wand systems available from Henkel Corporation, Rocky Hill, CT.

[098] The following examples are included for purposes of illustration so that the disclosure may be more readily understood and are in no way intended to limit the scope of the disclosure unless otherwise specifically indicated.

EXAMPLES Example 1.

[099] A UV curable composition (sample 1) was prepared according to Table 1.

Table 1 Composition of Sample 1 Wt % 4-t-Butylcyclohexyl Methacrylate 45.8 Hydroxypropyl Methacrylate 5.6 Acrylic Acid 5.5 1,3 Butylene Glycol Dimethacrylate 10.9 Surfactant1 1.8 Saccharin 1.0 I -Acetyl-2-phenyIhydrazine 0.2 Methylene diphenyl diisocyanate acrylic copolymer2 7.3 Cumene Hydroperoxide 1.0 Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide 2.0 B i s(m eth acryloxy I ethyl)ph ospate 5.0 Naphthoquinone 0,01 Sodium EDTA 0.04 urethane acrylate 13.6 Fluorescent dye 0.02 Total | 100 Octylphenoxypolyethoxyethanol with Polyethylene Glycol See U.S. Patent No.s 4,018,851; 4,295,909; 4,309,526; 6,596,808 IE 1 2 0 3 6 5 [0100] 99% pure copper tubing was obtained. Tubing ends were formed to provide a male distal portion outside diameter of 5.85 to 5.95 mm and a female distal portion inside diameter of 6.00 to 6.15 mm.

[0101] Complementary sets of tubing, one member having a reduced outside diameter (OD) and the other member having an expanded inside diameter (ID), were chosen. Each set of tubing had a curable composition applied to both the male distal portion and the female distal portion. 5 sets used a composition according to sample 1. Another 5 sets used Loctite 661, a high strength adhesive composition curable by UV exposure and/or under anaerobic conditions available from Henkel Corporation.

[0102] The distal portions were assembled by manually inserting the male distal portion into the female distal portion. The connections were a slip fit (had a clearance between overlapped distal portions of about 0.05 mm to about 0.30 mm) and an axial overlap.

[0103] Each assembly was exposed to UV light at an intensity of 6 mWcm' for 10 seconds using a Loctite 7700-HD UV light source. Each assembly was allowed to stand for 3 minutes. [0104] After 3 minutes each cured assembly was pressurized to 15 bar (1500 kPa) with compressed air and held in a water bath. Any bubbles emerging from the cured connection was marked as a failure. Results are shown in Table 2.

Table 2 replicate comparative1 sample 1 1 fail pass 2 fail pass 3 fail pass 4 pass pass5 fail pass Loctite 661 [0105] High pressure connections prepared using the composition of sample 1 repeatably passed the 15 bar (1500 kPa) test while connections made using Loctite 661 were generally not able to pass this test.

It 1 2 0 3 6 5 Example 2 [0106] 99% pure copper tubing was obtained. Tubing ends were formed to provide a male distal portion outside diameter of 5.85 to 5.95 mm and a female distal portion inside diameter of 6.00 to 6.15 mm.

[0107] Complementary sets of tubing, one member having a reduced outside diameter (OD) and the other member having an expanded inside diameter (ID), were chosen. Each set of tubing had the curable composition of sample 1 applied to both the male distal portion and the female distal portion.

[0108] The distal portions were assembled by manually inserting the male distal portion into the female distal portion. The connections were a slip fit (had a clearance between overlapped distal portions of about 0.05 mm to about 0,30 mm) and an axial overlap.

[0109] Each assembly was exposed to UV light at an intensity of 6 mWcrn2 for 10 seconds using a Loctite 7700-HD UV light source. Each assembly was allowed to stand for 3 minutes. [0110] After 3 minutes each cured assembly was pressurized with oil using a hydraulic pump. The pressure was raised incrementally to more than 200 bar (20,000 kPa). Any leakage from the cured connection was marked as a failure. Results are shown in Table 3.

Table 3 replicate sample 1 1 >200 bar 2 >200 bar 3 >200 bar 4 >200 bar 5 >200 bar

[0111] High pressure connections prepared using the composition of sample 1 repeatably passed the 200 bar (20,000 kPa).

Claims (19)

1. WHAT IS CLAIMED:

1. A method of making a high pressure connection, comprising: providing the first tubular member having a distal joint portion; providing the second tubular member having a distal joint portion; applying a radiation curable composition to one of the distal joint portions, the radiation curable composition comprising a reactive component having polymerizable acrylate functionality and a photoinitiator; sliding the second tubular member distal joint portion into the first tubular member distal joint portion, the first member outer surface defining an exterior surface of the high pressure connection and the second member inner surface defining an interior surface of the high pressure connection; exposing the curable composition on the exterior surface of the high pressure connection to radiation sufficient to initiate curing ofthe composition within the high pressure connection at a commercially reasonable speed, wherein cured reaction products of the curable composition maintain the second tubular member distal joint portion within the first tubular member distal joint portion thereby forming the high pressure connection in less than 10 minutes.

2. The method of claim 1 wherein one of the first or second tubular members is aluminum and the other of the members is selected from copper, aluminum, steel, coated steel, stainless steel and plastic.

3. The method of claim 1 wherein the photoinitiator comprises a phosphine oxide photoinitiator.

4. The method of claim 1 wherein the curable composition further comprises an initiator component for initiating curing ofthe composition in the absence of air.

5. The high pressure connection of claim 1 consisting essentially of the first tubular member, the second tubular member and cured reaction products of the radiation curable composition bonding the first and second members.

6. A high pressure connection, comprising: a first tubular member having a first distal joint portion including a substantially cylindrical outer surface free from threads, a substantially cylindrical inner surface free from threads having an inner diameter defining a bore through the member, and a circumferential first end connecting the outer and inner surfaces; a second tubular member having a second distal joint portion including a substantially uniform cylindrical outer surface free from threads and defining an outer diameter smaller than the first member inner diameter, a substantially uniform cylindrical inner surface free from threads defining a bore through the member, and a circumferential second end connecting the outer and inner surfaces, the second distal joint portion disposed within the first distal joint portion, wherein the outer diameter is substantially constant over the length of the second distal joint portion; and a cured reaction product of a radiation curable composition disposed between the distal joint portions; wherein one of the first tubular member or second tubular member is aluminum and the other is selected from aluminum, copper, brass, steel, coated steel, stainless steel and plastic.

7. The high pressure connection of claim 6 wherein there is no plastic deformation of the distal joint portions after the second distal joint portion is disposed within the first distal joint portion.

8. A refrigeration system, a gas compression system or a drink dispenser comprising the two part, high pressure, fluid impermeable connection of claim 6.

9. A method of making a high pressure connection, the connection consisting essentially of a first distal joint portion, a second distal joint portion and cured reaction products of a radiation curable composition disposed between the first and second distal joint portions, comprising: providing the first distal joint portion including an outer surface free from threads, a substantially uniform cylindrical inner mating surface free from threads having an inner diameter defining a bore through the distal joint portion, and a circumferential end connecting the outer and inner surfaces; providing the second distal joint portion including a substantially uniform cylindrical outer mating surface free from threads and defining an outer diameter smaller than the first distal joint portion inner diameter, a substantially uniform cylindrical inner surface free from threads defining a bore through the distal joint portion, and a circumferential end connecting the outer and inner surfaces; applying a radiation curable composition to at least one of the distal joint portion mating surfaces, the radiation curable composition comprising a reactive component having polymerizable acrylate functionality, a photoinitiator and an initiator component for initiating curing of the composition in the absence of air; sliding the second distal joint portion into the first distal joint portion to form an assembly having a bond area between the mating surfaces and an exterior surface; exposing the assembly exterior surface to radiation sufficient to initiate curing of composition in the bond area at a commercially reasonable speed, wherein cured reaction products of the curable composition in the bond area maintain the second tubular member distal joint portion within tbe first tubular member distal joint portion thereby forming the high pressure connection.

10. The method of claim 9 wherein the high pressure connection is a two part connection consisting essentially of the cured composition, a first tubular member including the first distal joint portion and a second tubular member including the second distal joint member. ’·? /¾ v ύ 0 Ο <3 if·;.

11. The method of claim 9 wherein the high pressure connection is a multiple part connection consisting essentially of the cured composition, a connector including the first distal joint portion and a second tubular member including the second distal joint member.

12. The method of claim 9 wherein the first distal joint portion outer surface defines an exterior surface of the high pressure connection and the second distal joint portion inner surface defines an interior surface of the high pressure connection.

13. The method of claim 9 wherein: the first distal portion extends from a first tubular member, the first tubular member having an unjoined length at least about ten times the first distal joint portion inner diameter; and the second distal joint portion extends from a second tubular member, the second tubular member having an unjoined length at least about ten times the second distal joint portion outer diameter.

14. The method of claim 9 wherein the high pressure connection remains impermeable to a refrigerant at a pressure of at least 650 pounds per square inch.

15. The method of claim 9 wherein one of the first or second distal joint portions is aluminum and the other of the distal joint portions is selected from copper, aluminum, steel, coated steel, stainless steel and plastic.

16. The method of claim 9 wherein the curable composition comprises about 70 % by weight to about 90 % by weight of a (meth)acrylate component; about 0.75 % by weight to about 2.5 % by weight of an anaerobic cure inducing component; about 1 % by weight to about 5 % by weight of a photoinitiator component. IE 120365

17. The method of claim 9 further comprising the step of avoiding plastic deformation of the distal joint portions after the second distal joint portion is slid within the first distal joint portion,

18. The method of claim 9 wherein the step of applying the radiation curable composition to at least one of the distal joint portion mating surfaces comprises providing the radiation curable composition to the assembled distal joint portions.

19. The method of claim 9 wherein the high pressure connection is a Ό shaped return bend.