JPS6346959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a connecting device and its uses, and more particularly to a device and a connecting method capable of connecting to a substrate via a heat-recoverable memory metal member.

As is known, "memory metal"
Metals, sometimes referred to as "memory alloys," are metallic materials that can be used to make heat recoverable articles. A heat recoverable article is capable of deforming from an initial heat stable structure to a different heat unstable structure and remaining in that unstable structure at a temperature (or narrow temperature range) known as the transition temperature.
When heated to , it returns or attempts to return to its initial structure. That is, the heat recoverable article is understood to be capable of returning toward its initial configuration without further application of external forces.

Such metals and their applications are described in U.S. Patent No.
No. 3174851, No. 3351463, No. 3753700, No.
No. 3759552, No. 3783037, No. 4019925, No.
4036669, 4067752, 4095999 and British Patents 1327441, 1327442, 1395601,
No. 1488393, No. 1420682, No. 1504707, No.
No. 1553427, No. 1548965, No. 1554431, No.
No. 1554432 and No. 1554423.

Devices that can be connected to at least one substrate via a heat-recoverable memory metal are known, for example, as pipe fittings or electrically conductive material connectors. Although such devices may be satisfactory in some cases,
In other cases, for example, when connecting thin-walled pipes made of relatively soft metals such as aluminum or copper, which are exposed to high liquid pressure, or when connecting certain electrical conductors, especially aluminum electrical conductors. This was unsatisfactory when connecting conductors covered with an oxide film.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a device connectable to at least one substrate, comprising at least one heat-recoverable memory metal member which, when recovered, covers at least one surface of the device. the surface of which is coated, at least in part, with a layer of sealant having a particulate filler dispersed therein, which filler is bonded to the substrate upon recovery of the memory metal component; To provide a connecting device that is recessed.

The present invention further provides the steps of: disposing at least one surface of the device adjacent a substrate with an intervening sealant layer having a particulate filler dispersed therein, and sealingly engaging the surface of the device to the substrate upon recovery; and a method of connecting an apparatus to at least one substrate, the method comprising: providing a heat-recoverable memory metal member capable of driving the filler into the substrate; and then heating to recover the heat-recoverable member. provide.

Preferably, the device of the invention includes at least one non-thermally recoverable member, the member being plastically deformable and having a surface capable of interlocking with the substrate, and having at least one non-thermally recoverable member. It is desirable that the non-heat-recoverable member acts as a member that promotes engagement of the base material.

In one preferred embodiment of the invention, the device is in the form of a liquid-tight fitting used to connect a plurality of soft metal pipes, such as copper or aluminum. In this embodiment, a hollow, non-heat-shrinkable tubular member is used, having an appropriate number of inlets and outlets coupled to the pipe to be connected. (The term tubular as used herein is used in a broad sense and includes members of irregular and/or variable cross-section, Y-shaped, T-shaped and X-shaped members, as well as one or more closures. It also includes those with edges.Therefore,
It is not limited to a true cylindrical shape. ) For example, if a set of aligned pipes must be connected, a substantially straight tubular non-thermally recoverable member may be
Advantageously, it is used with a memory metal member which is also tubular and is arranged coaxially around the non-thermal recovery member.

In a second preferred embodiment of the invention, the device comprises a copper or aluminum electrical conductor, in particular a bus-bar of an electrical switch gear.
It has the shape of a connector for high-voltage conductors such as bar). In such embodiments, a plurality of non-heat shrinkable shell members are disposed and positioned around the electrical conductor ends to form a generally tubular connection assembly.
Additionally, a plurality of band-like or annular heat-recoverable memory metal members are also disposed to act as propellants, each propellant being positioned at or near an end of the connecting assembly such that recovery of the propellant turns the connecting assembly into a conductive material. Make sure to engage. An example of an electrical connector to which the second preferred aspect of the invention relates is disclosed in British patent application 47370/78.

The choice of sealant depends on the nature of the application. In the case of pipe fittings that withstand high pressure and must first consider high shear strength when used,
The sealant is preferably an adhesive, particularly an adhesive that has low tackiness, is solid at 25° C., softens when heated, and simultaneously softens and flows if heat recovery occurs upon heating. Of particular interest are adhesives in which the adhesive itself is thermoset, and upon heating undergoes a chemical change such as a crosslinking reaction, which serves to develop or enhance adhesion after cooling.

A suitable cured epoxy resin has an epoxy equivalent weight of 100
~5000, preferably 600 to 800 epoxy resins, such as 5 to 95 parts by weight of bisphenol A epoxy resins, epoxy equivalents having at least 4 functional groups
200-500 epoxy resin, such as cresol
5 to 95 parts by weight of a novolac-type resin and approximately stoichiometric proportions of a curing agent, such as a phenolic resin,
Preferably, resins comprising bisphenol A, acid anhydrides, amines or amides having a molecular weight of about 500 are included. In order to increase the flexibility of the epoxy resin composition after curing, a small amount, for example 5 to 20% by weight, is added to the composition.
A carboxy-terminated butadiene-nitrile rubber can be formulated which reacts with the epoxy resin to provide a crosslinkable graft copolymer resin. The rubber preferably has a molecular weight of 3000 to 4000, such as about 3500, a nitrile content of 10 to 27%, such as about 18%, and a carbonyl functionality per molecule.
1.5 to 3, for example about 2. When using such a curing system, heating must be continued for a sufficient period of time after the adhesive has flowed to obtain the desired degree of cure. For example, 150~ for epoxy resin type
Heating at 250°C for up to 3 minutes is generally suitable.

In the case of electrical connectors, a low-conductivity or non-conductivity surface coating on the electrical conductor to be connected;
For example, in aluminum conductors, the influence of penetration into particularly tough oxide layers on a good electrical connection must first be considered. Therefore, any sealant that can prevent such rearrangement of the surface layer can be used, for example, a sealant that can eliminate oxidative effects such as oxygen. For electrical applications, the sealant used is preferably electrically conductive. The sealant can be a viscous mastic or one that is non-flowing after installation, such as the sealants already mentioned for pipe fittings, which are mixed with electrically conductive fillers in a known manner to provide electrical conductivity. is preferable.

The sealant composition is preferably applied to the surface of the member that contacts the substrate, but the interface is coated by conventional methods.
For example, it can also be supplied by coating on a substrate. The initial thickness of the sealant coating, i.e. before installation on equipment, should be between 0.25 and 3 mils, especially between 1 and 3 mils.
1.75mil is preferred. The thickness of the sealant coating after recovery of the storage metal component is, for example, less than about 0.1 mil. At least one surface in contact with the sealant is preferably treated, eg by sand-blasting, to improve wetting by the sealant, eg to improve adhesion if adhesives are used.

To achieve the objects of the present invention, when the device surface and the substrate are mated by a sealant therebetween, such as a heat softenable adhesive composition, the particulate filler is applied to the substrate, preferably to the substrate. It is important that the mating surfaces also undergo partial deformation. Where shear strength is of paramount importance and adhesives are used, the filler particles provide an anchoring effect between the adhesive and at least one of the adjacent surfaces after installation of the device when the adhesive is in the solid state. , which improves the shear strength of the bond between both surfaces. Particularly good results are obtained when each particle of filler partially penetrates both adjacent surfaces, forming bonding bridges between the two surfaces. For this reason, the filler should have at least one of its one-dimensional dimensions greater than or equal to 0.05 mil, especially
Preferably, the particles are 0.1 mil or larger. On the other hand, the possible degree of recovery of the heat-recoverable component (and in some cases the method employed to form the adhesive composition layer) limits the maximum particle diameter;
Desirably, the largest one-dimensional dimension of the particles is less than or equal to 5 mils.

If a satisfactory electrical connection is a primary consideration, the filler particles must be such that, after installation of the device, they penetrate the surface layer of the conductive material, for example the oxide layer. It is also preferable to utilize high shear strength in the case of electrical connectors;
Therefore, filler particles having the above-mentioned particle size are preferably used also in electrical applications.

In order to achieve the desired anchoring effect or surface layer penetration, it is preferred that the filler particles have an aspect ratio of 2 or less.

The filler used in the present invention is preferably one that can bite into the base material, preferably into the surface of the device.
For this purpose, the hardness of the filler is determined by the hardness of the base material,
and preferably greater than the hardness of the device surface. Suitable fillers are quartz, alumina and other ceramics, silicon carbide and metals such as nickel. For electrical applications,
Conductive fillers such as metals, especially nickel or silicon carbide, are suitable.

The amount of filler present in the sealant is preferably 10-50%, more preferably 20-40%, such as about 30% by weight of the total sealant system.

If a non-thermal recoverable member is used in addition to the heat recoverable member, the non-thermal recoverable member has a melting point substantially higher than any temperature reached during installation;
For example, it must have a melting point of 300° C., preferably 500° C. or higher, and is preferably made of metal or a composite material with similar properties.
As mentioned above, the non-thermally recoverable member is preferably plastically deformed by the recovery of the heat-recoverable member. In a preferred arrangement resulting from such deformation and suitable for tubular substrates, the non-thermally recoverable member, preferably made of metal, is tubular and the memory metal member is coaxially attached to the non-thermally recoverable member. Adjacently disposed radially heat recovery tubes. The memory metal member is preferably heat shrinkable and disposed around the non-thermal recovery member. The surface of the non-thermally recoverable member remote from the memory metal member is generally smooth, but may consist of annular radial teeth adapted to engage the substrate. However, it must be noted that if such teeth are present, the margins of the teeth generally require a relatively thin application of the adhesive composition, or no adhesive composition at all. This is because there is a limit to the radial deformation caused by the second member.

The non-thermal recovery member and the memory metal member and base preferably have an annular cross section. Often these cross-sections are substantially the same throughout their length. However, when connecting base materials with different outer diameters, at least the inner diameter of the inner member may be stepped.

Applying a thermochromic coating to all or part of the external surface of a non-thermally recoverable member that indicates when heated to a certain temperature, which, if a softening adhesive is used, indicates the temperature reached by the adhesive composition. It can be an indication of temperature. On the other hand, it is also possible to mix a thermochromic paint with the softenable adhesive composition used and apply it so that a part of the heat-recoverable member is visible when it is recovered.

The memory metal preferably has a temperature of about 40°C or higher, e.g.
As at 40-150℃ (austenite start)
start) temperature (inherently or as a result of pretreatment)
As a result, it is made of a metal that can be stored at room temperature and, if a heat-softening adhesive is used, its softening and metal recovery can be carried out in the same heating step. Good results have been obtained with parts made of β-brass (β-brass is described in US Patent Application No. 783040, No. 783041 and No. 797621). After the heat recoverable member recovers,
It is generally left in place, but when used to cause plastic deformation of other members in contact with the substrate, it may be removed after the other member has been deformed as desired. If left as is,
The heat recovery member is preferably made of a metal whose normal As temperature is below room temperature, but whose initial As temperature is above room temperature (20°C) through pretreatment (for pretreatment, for example, Patent Application No. 550847, No. 735737 and No.
779360). On the other hand, when removing the first member, the transition temperature is preferably room temperature or higher.

When a non-thermal recovery member is used in addition to a heat recovery member, the length of the non-thermal recovery member is generally the same as or slightly shorter than the length of the heat recovery member.
However, as previously discussed, two or more identical or different heat recoverable members, such as two cylindrical heat recoverable members, may be used to apply forces to different portions of the non-thermal recoverable member. can.

As mentioned above, the present invention is useful for connecting pipes of substrates, especially soft metals such as aluminum or copper, and is also useful for connecting pipes of thin walled materials, e.g. d is 0.15 or less, for example 0.1
Typically the wall thickness is less than 100mil, for example 20~
50mil, it is also useful for pipes such as those widely used in cooling and air conditioning equipment. The outside diameter of such pipes generally ranges from 0.25 to 100 inches.

The substrates to be connected may be of the same or different materials and of the same or different sizes. If a non-thermal recoverable member is used in addition to the heat recoverable member, it is preferably constructed of the same metal as one or both of the pipes to be connected. It is also preferred that the contacting surface exerts a substantially uniform pressure on the substrate.

Next, specific examples of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a plan view (partially in section) of the connecting device of the invention before recovery, placed on two pipes to be connected;

FIG. 2 is a sectional view taken along line AA in FIG. 1.

FIG. 3 is a cross-sectional view of a portion of the interface between the connecting device and one tube after recovery.

FIG. 4 is a plan view (partially in section) of another connecting device according to the invention before recovery, placed on two pipes to be connected;

1 and 2, two pipes 5 to be connected by a connecting device consisting of a tubular plastically deformable member 1 and a tubular heat-shrinkable member 2 are shown.
and 6 are shown. The deformable member 1 has an adhesive composition 3 coated on its inner surface.

Adhesive composition 3 consists of a partially cured epoxy resin and about 20% by weight of quartz particles, based on the total composition. At the outer edge of the deformable member 1 there is a thermochromic paint coating 4 .

FIG. 3 shows the interface between the pipe 5 and the deformable member 1 after the assembly of FIGS. 1 and 2 has been heated to cause recovery of the member 2 and the composition 3 has been melted and hardened. Quartz particles 33 in the adhesive composition dig into both surfaces.

FIG. 4 shows a heat-shrinkable member 2, whose inner and outer surfaces are coated with the aforementioned adhesive composition 3, positioned over the pipes 5 and 6 to be connected. ing.

The adhesive composition used above and suitable for powder coating is prepared by grinding and classifying a composition of the following components: Bisphenol A (epoxy equivalent approximately 750. Epon 2001) 38 wt. Polyfunctional epoxy cresol novolak type resin (epoxy equivalent: approx. 230).
ECN1280) 4.25 parts, bisphenol A polymer curing agent (molecular weight approximately 500.XD8062.01) 17.75 parts by weight, quartz particles (P Quartz) 20.00 parts,
19.5 parts TiO ₂ , 0.5 parts by weight of carbon black (Statex 160).

The particle size distribution of the quartz particles is as follows.

80 mesh screen retention 0% by weight 100 mesh screen retention 0.1% by weight 120 mesh screen retention 0.1% by weight 140 mesh screen retention 0.9% by weight 160 mesh screen retention 0.7% by weight 200 mesh screen retention 3.3% by weight 270 mesh Retention of mesh screen: 5.9% by weight Retention of 325 mesh screen: 8.8% by weight Passage of 325 mesh screen: 80.2% by weight The classified composition is applied by powder coating to the inner surface of a true cylindrical copper tube which has been previously sandblasted. The tube has an inside diameter of 0.764 inches, an outside diameter of 0.848 inches, and a length of 1.5 inches. The outer surface of the tube is
It is surrounded by a heat-shrinkable polyethylene tube. The coated tube is heated sufficiently until the particles in the adhesive composition aggregate to form a layer approximately 2 mils thick. The polyethylene coated tube is then removed.

A true cylindrical radial heat-shrinkable tube with a length of 1.2 inches, an outer diameter of 1 inch, and an inner diameter slightly larger than 0.848 inch (thus fits into the copper tube with a slight clearance) is made of β-brass cooled with liquid nitrogen. Manufactured by stretching in the radial direction. β-brass has As of about 40~50℃
It is processed so that it has The heat-shrinkable beta-brass tube is removed from the liquid nitrogen and placed in the center of the copper tube. The copper tube is strong enough to withstand the radial shrinkage of the beta-brass under normal storage conditions.

The ends of two copper tubes having an outside diameter of 0.75 inches and a wall thickness of 35 mils are placed into adhesive coated copper tubes as shown in FIG. The assembly was then heated at 200° C. for 1 minute to recover the β-brass tube and melt the epoxy resin composition.
Then harden.

The connections thus formed were very strong, with a pull-out strength of over 1000 Psi at room temperature and 150°C, and were able to hold an internal pressure of 3000 Psi at room temperature and 150°C.

Similar results were obtained when aluminum tubes were used instead of copper tubes in the connecting device and when one or both of the copper tubes to be joined were replaced by aluminum tubes of the same size.

[Brief explanation of the drawing]

FIG. 1 is a plan view (partially in section) of the connecting device of the invention before recovery, placed on two pipes to be connected; FIG. 2 is a sectional view taken along line AA in FIG. 1. FIG. 3 is a cross-sectional view of a portion of the interface between the connecting device and one tube after recovery. FIG. 4 is a plan view (partially in section) of another connecting device according to the invention before recovery, placed on two pipes to be connected; DESCRIPTION OF SYMBOLS 1... Deformable member, 2... Heat-shrinkable member, 3... Adhesive composition, 4... Thermochromic paint coating, 5, 6... Pipe, 33... Quartz particles.

Claims (1)

[Scope of Claims] 1. (a) a member made of a heat-recoverable memory metal having a surface that sealingly engages a target substrate upon recovery; and (b) a member of the surface of the heat-recoverable memory metal member. A connection device comprising a sealant layer coated on at least a portion of the heat-recoverable memory metal member, wherein the sealant layer protects the base member when pressed against the base member by the heat-recoverable memory metal member when the member recovers. A connecting device comprising particulate filler dispersed in the layer so as to bite into the layer. 2. The connecting device according to claim 1, wherein the sealant is an adhesive. 3. The connecting device according to claim 2, wherein the adhesive can be softened by heating. 4. A connecting device according to claim 3, wherein the adhesive comprises a polymer phase. 5. The connecting device according to claims 2 to 4, wherein the adhesive is a thermosetting adhesive. 6. The connecting device according to claim 5, wherein the adhesive is a curable epoxy resin. 7 The thickness of the sealant layer before installing the connection device is 0.25
7. A connecting device according to any one of claims 1 to 6, wherein the connecting device is 3 mil. 8 The thickness of the sealant layer after the connection device is installed
The connection device according to any one of claims 1 to 7, which has a thickness of 0.25 mil or less. 9. The connecting device according to any one of claims 1 to 8, wherein the granular filler has an aspect ratio of 2 or less. 10. The connecting device according to any one of claims 1 to 9, wherein the hardness of the granular filler is greater than the hardness of the surface of the connecting device and the base material to be engaged. 11. The connecting device of claim 10, wherein at least some of each filler particle penetrates the connecting device surface and the substrate to form a bonding bridge therebetween after installation of the connecting device. 12. A connection device according to any one of claims 1 to 11, wherein the filler comprises particles having at least one of their one-dimensional dimensions larger than 0.05 mil. 13. The connection device of claim 12, wherein the filler material comprises particles having at least one of their one-dimensional dimensions greater than 0.1 mil. 14 Claims 1 to 13 in which the filler comprises quartz, alumina, silicon carbide or metal particles
Connecting device according to any of paragraphs. 15 Claims 1 to 1 in which the amount of filler in the sealant is 10 to 50% by weight of the total sealant system
The connection device according to any one of Item 4. 16. The connection device according to any one of claims 1 to 15, wherein the heat-recoverable memory metal member is made of β-brass. 17. The connecting device according to any one of claims 1 to 16, wherein the sealant layer includes a thermochromic paint that becomes visible when sufficient heat is applied to ensure proper attachment. 18 (a) a heat-recoverable memory metal member; (b) disposed in the recovery direction of the heat-recoverable memory metal member, and when the heat-recoverable memory metal member recovers;
a non-recoverable member having a surface that sealingly engages a target substrate; and (c) a sealant layer coated on at least a portion of the surface of the non-recoverable member. , the sealant layer includes a particulate filler dispersed therein so as to bite into the substrate when pressed by the heat recoverable storage metal member against the substrate when the member recovers. 19. The connecting device according to claim 18, wherein the non-thermally recoverable member is plastically deformable. 20. The connection device according to claim 18 or 19, wherein the non-thermal recovery member is metal. 21. The connection device according to any one of claims 18 to 20, wherein the non-thermal recovery member is tubular. 22. The connection device of claim 21, wherein a radially heat-recoverable tubular memory metal member is disposed around a non-thermal-recoverable member. 23. A connecting device according to any of claims 18 to 20, wherein the non-thermally recoverable member is a generally tubular assembly. 24 comprising a plurality of radial heat recoverable rings or bands;
24. The connection device of claim 23, wherein the ring or band is located at or near an end of a generally tubular assembly of non-thermal recoverable members. 25. The connection device according to any one of claims 18 to 24, wherein the heat recovery member is made of β-brass. 26 Claims in which the sealant layer contains a thermochromic paint that becomes visible when sufficient heat is applied to ensure proper installation, or where a coating of the thermochromic paint is applied to the external surface of the non-thermally recoverable member. Range 18th~
26. The connection device according to any one of Item 25. 27 (a) a member comprising a heat-recoverable memory metal having a surface that sealingly engages a target substrate upon recovery;
and (b) a connection device comprising a sealant layer coated on at least a portion of the surface of the heat-recoverable memory metal member, wherein the sealant layer is applied when the heat-recoverable memory metal member recovers. , a method of forming a connection between a target substrate and a connection device including a particulate filler dispersed therein so as to bite into the substrate when pressed against the substrate by the member, (1) the base material adjacent to the connecting device in the recovery direction of the heat recoverable memory metal member such that the sealant layer is present between the heat recoverable memory metal member and the base material; and (2) heating and restoring the heat-recoverable memory metal member, pressing the sealant layer onto the base material, and pressing the granular filler into the base material. A method comprising. 28 Claim 27, in which a connecting device is connected to a plurality of base materials in order to connect the plurality of base materials to each other.
The method described in section. 29 Claim 2 in which a connecting device is connected to a plurality of pipes so that liquid does not leak between the pipes.
The method described in Section 8. 30 The ratio w/d of the wall thickness w and the outer diameter d of each pipe is
29. The method according to claim 29, wherein the value is 0.1 or less. 31. The method of claim 30, wherein the wall thickness is between 20 and 50 mils. 32. The method according to claim 27 or 28, wherein the base material is a plurality of electrical conductors, and the electrical connection between the electrical conductors is achieved. 33 (a) a heat-recoverable memory metal member; (b) disposed in the recovery direction of the heat-recoverable memory metal member, and when the heat-recoverable memory metal member recovers;
a non-recoverable member having a surface that sealingly engages a target substrate; and (c) a sealant layer coated on at least a portion of the surface of the non-recoverable member, the connection device comprising: The sealant layer is applied to a connecting device that includes a particulate filler dispersed therein so as to bite into the substrate when pressed by the heat-recoverable memory metal member against the substrate when the heat-recoverable memory metal member recovers. A method of forming a connection between a heat-recoverable memory metal member and a base material, the method comprising: (2) heating the heat-recoverable memory metal member to recover it, and applying the sealant layer to the base material via a non-heat-recoverable member; and pressing the particulate filler into the substrate. 34 A method of connecting a member whose surface to be connected is made of a first material to at least one substrate whose surface to be connected is made of a second material, the method comprising: (a) connecting both surfaces; (b) consisting of a polymeric phase softened by heating and in which particulate fillers are dispersed between the surfaces, the fillers being two
(c) providing an adhesive composition layer having an aspect ratio of less than or equal to and a hardness greater than the first and second materials at a temperature at which the adhesive composition softens; (c) comprising a heat recoverable memory metal; , disposing a member that, upon thermal recovery, can bring the surface of the first material into contact with the surface of the second material through the layer of adhesive composition, and then (d) the adhesive composition. is heated to a temperature at which it softens, and further heats a heat-recoverable member to recover it,
A connection method comprising the step of bringing both surfaces into sealing contact with each other and causing partial deformation of at least one surface by the granular filler. 35. Claim 34, wherein the member whose surface to be connected is made of the first material is non-thermally recoverable.
The method described in section.