JPS63503158A - heat recoverable device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] heat recoverable device Background of the invention Confinement The present invention is useful for repairing, reinforcing, connecting or modifying thermally recoverable devices and substrates. regarding its use.

Overview of the invention Heat recoverable devices to repair, reinforce, connect or modify many types of substrates It is known that it can be used. It is also made of conductive polymer and has a suitable electrical charge. Such a heating element generates heat to recover the device when connected to a source. It is also known that the device may comprise: The heating element is itself heat recoverable. may be present and/or attached to a recoverable article and not impede recovery of the article. It's okay to be like this. For example, U.S. Pat. No. 4,085°286, No. 4,177.376, No. 4,177.446, No. 4,421゜582, No. 4, 570,055 and 4,575,618, United States Patent Application No. 63 No. 4,242, No. 720,117 and No. 720,118, and corresponding European Patent Application Publication Nos. 0.157,640 and 0.197,759 You can refer to the issue. Each of these patents and patent applications are referenced in this application. (U.S. Patent Application No. 720.1) 17) by means of a heat-shrinkable connecting member fused to the pipe. When we conducted a bending test on the connection between polymer pipes that were connected together, we found that the connection between the pipes was It has been found that failure of the joint occurs substantially before failure of the connected part. this contrasts with results obtained in other tests where the connection was stronger than the pipe itself; Comprehensive. Also, cracks in the pipe under the connecting member and near the end of the connecting member Destruction was also found. By considering this issue, this early failure can be prevented. to the extent that it substantially adversely affects the resistance to cracking when bending during continuous operation. It has been found that this occurs by heating the pipe to a sufficiently high temperature. Furthermore, inside The pipe can be connected using a connecting member that has an end section that is heated to a lower temperature than the central section. A sufficient amount of bending stress is supported by the connecting member so that the weakening of the The weakening of the pipe due to overheating should occur only in the central part of the connection It was discovered that this problem could be solved.

In a first aspect, the invention provides a radially heat-shrinkable hollow member, preferably a cylindrical a connecting member comprising: (1) a conductive polymer; (2) at least two heat-shrinkable end portions, each adjacent to the heat-shrinkable end portion; comprising at least two heat-shrinkable intermediate portions in contact with each other, and (3) Can be contracted by passing an electric current in the longitudinal direction; at least one the end portion has a wall thickness that is at least 1.05 times the wall thickness of the adjacent intermediate portion; do. By increasing the wall thickness, the end section has less resistance, which ( (along with other factors such as greater heat loss from the middle than the bottom of the end section) The underside of the section becomes hot, resulting in shrinkage of the end section, but overheating of the thermoplastic pipe You can avoid heat.

The end portions are preferably identical to each other, but may be different. The middle part is mutually In this case, it is connected to connect something like a base material. It behaves the same way when using parts, but connecting things that are not like substrates. Two (or more) parts that behave differently when using a connecting member for There is a single intermediate portion that is conceptually divided into minutes. Alternatively, the intermediate portion is With several circumferential ribs on the central part, e.g. on the inner surface, to improve the connection of the materials They may be interconnected through a central portion.

The heat-shrinkable member of the present invention has a cylindrical connecting member shape, especially when connecting pipes. It is particularly useful and the invention will be described primarily with reference to such applications. But long repair or reinforcement or modification of the base material, e.g. adding a branch pipe to an existing pipe. It can also be used when adding Accordingly, in another aspect, the present invention provides two of the pipes, the method comprising: connecting pipes within the cylindrical connecting member defined above; Place the end of the pipe on the side and pass an electric current through the connecting member to heat it and restore it around the pipe. It consists of causing. In one preferred embodiment, each pipe is a thermoplastic made of plastic material, and the conditions for carrying out the method are such that one intermediate section is fused to one pipe. The adjacent end section contracts into compressive contact with the pipe. but the middle part of the other is not fused to the other pipe. The adjacent end will contract and come into compressive contact with the other pipe, but The conditions are such that it does not become fused to the pipe.

In another preferred embodiment, one pipe is made of metal and the other pipe is made of metal. made of a plastic material, and the conditions for carrying out the method are such that one intermediate section is a thermoplastic pipe. The adjacent end section shrinks and compresses the thermoplastic pipe. They touch but do not become fused, and the other middle part and the other end part are metal parts. The conditions are such that there is compressive contact with the pipe. In any of these aspects, the connection At least a portion of the surface of the thermoplastic pipe that becomes fused to the component is The thermoplastic material is heated to a temperature where it completely melts and comes into compressive contact with the end portion. The highest temperature that at least a portion of the surface of the plastic pipe reaches is the temperature at which the thermoplastic material melts. Lower than the temperature at which melting begins.

Brief description of the drawing The present invention will be explained with reference to the accompanying drawings, in which FIG. 1 shows an unexpanded blank for a connecting member. 2 is a longitudinal sectional view; FIG. 2 is a transverse sectional view taken along line - H in FIG. 1; Figure 3 shows the effect of the radial expansion of the blank shown in Figures 1 and 2. 2 shows an assembly for connecting two pipes with a connecting member formed by ; Figure 4 shows a side view of the wrap-around repair sleeve of the present invention placed around a pipe. This is a cross-sectional view: Figure 5 is a longitudinal sectional view taken along ■-■ in Figure 4 (pipes are not shown). ),and FIG. 6 is a plan view of another connecting member of the present invention.

Detailed description of the invention The present invention is particularly advantageous when the connecting member contracts and comes into direct physical contact with the substrate. At least one substrate consists of a thermoplastic material (or at least one substrate consists of a thermoplastic material) and at least one intermediate portion and There is a fusion bond with the thermoplastic material. The term "fused" refers to the relationship between the element and the outer surface of the substrate. There is sufficient intermolecular compatibility between the This term refers to the formation of a bond that provides greater mechanical performance. It is used in the specification. This is Adhesion 1 (1969), pp. 16-23 and Adhesion 2 (1970), pp. 16-2. On page 2, J.N. Anand (J.

by viscoelastic contact as defined by N., Anand) or by polymer -/continuous concentration of one polymer within the other polymer interface due to molecular diffusion processes across the polymer/polymer interface such that a gradient exists. It is something that However, the present invention provides certain thermoresponsive contact inserts, e.g. e.g. curable polymer inserts, hot melt adhesives, mastics or solders It can also be used when placing all or part of the heat-shrinkable material between the base material and the heat-shrinkable material. Ru.

In a preferred embodiment of the invention, at least one substrate consists of a thermoplastic material, The maximum temperature reached by the surface of the substrate below the end portion of the connecting member (herein referred to as , a plot for the material by differential scanning calorimetry measured in accordance with ASTM. The temperature at which a thermoplastic material begins to melt (defined as the temperature at which the curve first departs from a straight line) It is preferable that the temperature is lower than that of the substrate; also part (defined herein as the peak temperature of a similar plot) Preferably, the temperature is above the temperature at which the thermoplastic material completely melts. thermoplastic The material is preferably an organic polymer, e.g. The crystalline polymer may include a crystalline polymer. The composition comprises such a polymer and If desired, it may consist essentially of conventional polymeric stabilizers, or even up to 20% by weight, preferably not exceeding 10% by weight of one or more fillers. It may also contain an agent. Particularly suitable polymers include one or more ethylenic polymers. Polymers of saturated monomers, such as especially low, medium and high density polyethylene; polyolefins, including polypropylene, as well as polyvinyl chloride. Special Useful substrates include pipes, especially pipes made of thermoplastic materials, more particularly ASTM D-2513 and D-3350; The pipe is suitable, for example, for the transport of natural gas or water.

Heat-shrinkable members are made of conductive polymers that are compatible with the base thermoplastic material. is preferred, and the conductive polymer and the organic polymer within the thermoplastic material are preferably are at least 80%, especially at least 90%, of the same repeating units. Especially suitable Suitable conductive polymers include very high molecular weight polymers, especially organic polymers. - especially ultra-high molecular weight polyethylene (Ul-IMWPE) and conductive fillers, especially based on a sintered mixture of carbon black.

The connecting member is a continuous object, but (as shown in FIGS. 4 and 5, for example) Consisting of a first and second part that attaches as a "wrap-around" around the In this case, only a portion of the member needs to be heat-shrinkable. "end part" The term is used to mean a portion closer to the open end of the member than the adjacent intermediate portion. end portions include, but need not necessarily be, open ends, e.g. The open end does not necessarily have to be heat-shrinkable.

Particularly good results are obtained when the end section of the connecting member contracts and comes into compressive contact with the pipe. It was done. The term "compression contact" refers to the fact that the member exerts a hoop stress on the pipe after contraction. It is used to mean something. hoop stress plastic pipe Preferably, it is sufficient to form a circumferential depression around the . The existence of hoop stress is , helps the thermoplastic substrate resist the effects of cold flow that can occur over long periods of time. It is theorized that. Additionally, this feature prevents bending and Helps spread other stresses satisfactorily. The thicker the heat-shrinkable material, the However, the hoop stress that can act becomes larger.

The decrease in wall thickness, which is a characteristic of the heat-shrinkable member of the present invention, may be rapid, and in this case, , it is easy to distinguish between the end parts and the middle part. However, the decrease in wall thickness is gradual. It is preferable that this occurs frequently. Therefore, the wall thickness increases from each end of the member toward the center. There may be a gradual decrease and, in some cases, between the intermediate portions, such a decrease in wall thickness There is a central part where there is no small amount. The wall thickness gradually decreases in all or part of the part. If the thickness is small, the boundary between the end part and the middle part is the average of the maximum and minimum wall thickness of the member. Defined herein as a point of wall thickness equal to . The wall thickness of the end part is the same as that of the adjacent middle part. at least 1.05 times the wall thickness of the part, preferably at least 1.1 times, e.g. ．． 1 to 1.4 times; the wall thickness used here refers to the end portion and middle portion, respectively. This is the maximum wall thickness between the parts.

When connecting two plastic pipes together, the conditions are such that the ends of the pipes do not collide with each other. Conditions that allow adhesive bonding are preferred. Especially under such conditions, melt pipe material Place a support member inside the pipe to ensure that it does not drip inside the pipe. is preferable.

1 and 2, the connecting member of the invention is shown to be formed by a method involving radial expansion. An unexpanded blank is shown. In Figures 1 and 2, the blank l is , ram-extruded into a cylindrical shape and then processed into the shape shown. and UHMWPE blend with multiple small ribs on the inner surface. , a central portion 11 of approximately uniform inner and outer diameters. and constant outer diameter and center The two teeth have an inner diameter increasing from the end adjacent to the part toward the open end. It has perforated end portions 12 and 13.

Figure 3 shows the blanks shown in Figures 1 and 2 in the radial direction (the pipes to be connected). electrodes 24 and 25) to a substantially uniform inner diameter slightly larger than the electrodes 24 and 25. The connecting member 2 formed by attaching the is shown. Connect the electrode to a suitable power source to provide the desired heat distribution within the connecting member (and therefore also within the vibrator) when Shape and position so that In addition, FIG. pipes 3 and 4 and holding the pipes in place during the connection operation. Also shown is a support member 5 which helps prevent excessive deformation of the pool.

Lead wires that maintain contact with the electrodes during the connection operation, as shown schematically in Figure 3. When electrodes 24 and 25 are connected to a suitable power source via to make a tight fit and contact with the pipe.

Figures 4 and 5 represent the printers (shown in Figure 4 but not in Figure 5). Wraparound heat shrinkable repair 3 for repairing cracks 31 in plastic pipe 3 It is showing bu. The repair sleeve includes longitudinal electrodes 24 and 25 and heat shrinkable It is made of a conductive polymer and has a snap fit 261 and 271 that allows the rotation of the pipe. It comprises semi-cylindrical portions 26 and 27 which are fixed to each other by means of a screw. part 26 is a relatively thick end portion 262 and 263 and a relative It has a thin central portion 261. Portion 27 has a uniform wall thickness. Apply the electrode When connected to a suitable power source, the sleeve contracts and contacts the pipe, causing the central portion 261 becomes hotter than the rest of the sleeve so as to seal the crack 31 into the pipe 3. Now fused, the remaining portion of the sleeve shrinks into compressive contact with the pipe. However, it does not become fused.

In FIG. 6, the connecting member 2 includes a first heat-shrinkable portion of relatively large diameter and wall thickness. 27, a second heat-shrinkable portion 26 of relatively small diameter and wall thickness, and an axial It has circumferential electrodes 241, 242 and 243 spaced apart. all of the parts or Partial recovery shall be accomplished by connecting a suitable power source to a suitable pair of electrodes. Can be done.

X outside the car A connecting member blank was manufactured by the following method.

Carbon black (Ketjenblack) E C30 After drying approximately 14.5 parts by weight of 0, Akzo Chemie) , UHMWPE (Hostalen) GU with a Henschel compounder. About 150 parts by weight of R413 (manufactured by Hoechst) were blended. obtained The blend was ram extruded at about 255°C into rods about 3.26 inches in diameter.

The rod was cut and processed into blanks as shown in FIGS. 1 and 2. Blanc The center portion is approximately 1.5 inches long and the uniform outer surface is 2.5 inches long. The inner surface has 16 threads per inch machined thereon. with each thread having a depth of 0.025 inches and an inner diameter of 2.11 inches; each end The section is 1 inch long with a uniform outer surface of constant diameter of 2.59 inches and 2.11 inches from the diameter of the end adjacent to the center section to 1,94 inches of the other end. It has an inner surface that tapers uniformly at a 5° angle to the diameter.

The blank is then heated to approximately 135°C and a tapered mandrel is used to The mandrel was expanded to a uniform inner diameter of 5 inches and cooled in water at 20°C for 15 minutes. removed. Next, silver-containing paint (Electrodag) 504, manufactured by Acheson Colloids). An electrode was applied to the end of the expanded blank to obtain a connecting member as shown in Figure 3. . Each electrode measures 0.25 inches along the length of the member and 0.12 inches across the diameter of the member. It's getting longer.

Using the connecting member, Philips (Phil 1ips) Triscovibe (Driscopipe) Commercially available as 6500 series, inner diameter is 1 94 inches, outside diameter 2.375 inches, and consists of two polyethylene The two types were connected together. General Electric Polymers made of Ultem j commercially available from Iectric The pipe was placed in the coupler on the mer connection member. Connect the electrode to a 40 volt AC power source After approximately 2.5 minutes, the connecting member contracted into tight engagement contact with the pipe. Contact The connected parts were disconnected from the power supply and allowed to cool.

Inspection of the resulting connection revealed that the central part of the connection member was fused to the pipe and It was found that the end portions of the pipes melted and flowed, and were impact fused together. In contrast, The end of the connecting member was not fused to the pipe, but it contracted and the end of the connecting member It was in compressive contact with the pipe under such a force that the pipe slightly deformed.

Tests on the resulting connections showed that they had excellent properties, especially against rotational fatigue. The test was designed so that the pipes were fused together and fused along the entire length of the connecting member. However, otherwise the connecting member of the prior art is comparable to the connecting member of the present invention. They have been found to have a much longer lifespan than conventionally formed connections.

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Claims (12)

[Claims] 1. (1) Made of conductive polymer, (2) at least two heat-shrinkable end portions and at least two heat-shrinkable end portions adjacent to the heat-shrinkable end portion; Both have two heat-shrinkable intermediate portions, and (3) conduct electric current in the longitudinal direction. This allows it to contract. a radially heat-shrinkable hollow member, the at least one end portion being adjacent to the hollow member; A member having a wall thickness at least 1.05 times the wall thickness of the contacting intermediate portion. 2. Each end section has a wall thickness that is at least 1.1 times the wall thickness of the adjacent intermediate section. The member according to claim 1, comprising: 3. Each end portion has a wall thickness that is 1.1 to 1.4 times the wall thickness of the adjacent intermediate portion. The member according to claim 2. 4. The wall thickness gradually decreases from each open end of the connecting member toward the center. The member according to scope 2 or 3. 5. having a central portion with a plurality of circumferential ribs on the inner surface, existing between the intermediate portions; The member according to any one of claims 1 to 4, comprising: 6. Claimed material consisting of a sintered mixture of ultra-high molecular weight polyethylene and conductive filler. The member according to any one of items 1 to 5. 7. A pipe inside the connecting member defined in any one of claims 1 to 6. place the end of the pipe and apply a current to the connecting member to heat the member and cause it to contract around the pipe. A method of connecting two pipes that involves connecting the pipes together by How to do it. 8. One pipe is made of metal and the other pipe is made of thermoplastic material, the method The condition is such that one middle section is fused to the thermoplastic pipe, and the adjacent The end of the pipe shrinks into compressive contact with the thermoplastic pipe, but does not become fused. , the other middle section and the other end section are contracted to come into compressive contact with the metal pipe. 8. The method according to claim 7, which is provided under the following conditions. 9. Each pipe is made of thermoplastic material, and the conditions of the method are that the middle part of one is now fused to one pipe, and the adjacent end has shrunk to form a pipe. is in compressive contact with the pipe, but does not become fused, and the other intermediate section is fused to the other pipe. The adjacent end will contract and come into compressive contact with the other pipe. 8. The method according to claim 7, wherein the condition is such that the fusion bond does not occur. 10. The thermoplastic material is polyethylene, and the connecting member is made of polyethylene. A method according to claim 8 or 9, comprising a conductive polymer that is tyrene. . 11. The connecting member is a sintered mixture of ultra-high molecular weight polyethylene and carbon black. 11. The method of claim 10, comprising: 12. At least a portion of the surface of the thermoplastic pipe that becomes fused to the connecting member is heated above the temperature at which the thermoplastic material completely melts and is brought into compressive contact with the end section. The highest temperature reached by the surface of a thermoplastic pipe is the temperature at which the thermoplastic material melts. 12. A method according to any of claims 8 to 11, which is lower than the starting temperature.