JPS5851815B2 - netsukakuseibutsupin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to heat-recoverable members, particularly heat-shrinkable members, and such heat-shrinkable members according to the invention include cables,
It is used to encapsulate pipe or connector combinations or splices in place by being placed around them and subjecting them to heat recovery.

For example, sealing long and thin objects such as cables and pipes,
There are many instances where encapsulation or sealing is necessary for insulation or protection purposes.

Such wrapping operations are particularly important when, for example, pipes or cables containing joints with a plurality of pipes or cables are to be joined or spliced.

In many cases, it is common for the ends of elongated objects to be in a situation where it is not possible to cover them with a tubular sealing member.

In the following description, the elongated object will be collectively referred to as a cable.

Of course, the field of application of the invention is not limited to cables only, but also includes elongated objects such as pipes, ducts, conduits, etc., and in particular connections between these elongated objects.

Various sealing members have been developed for wrapping around the elongated object to overcome the above-mentioned disadvantages and seal cable connections.

As such a sealing member, for example, US Pat. No. 33,792
18, No. 3455336, and No. 3770556.

These so-called "Wraparoun"
d) The sealing member can be mounted around an elongated object without using the free end of the object.

However, electric wire cables for effectively protecting cables of different dimensions, especially two or more input cable ends and/or lap splice members with built-in lap splices, from the outside world without using their free ends. A sealing device for joints or lap joints (hereinafter referred to as "lap joint case").

It is clear that improvements to ) are still desperately needed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a thermally recoverable spliced case which is capable of accommodating as well as removing a plurality of cables of different dimensions or diameters. In some cases, it is also possible to reinstall the cable without using the cable end.

The method of the present invention is different from the "wrapping" method.

This is because, as an example, the present invention encapsulates the overlapped portion using a method that is somewhat different from the above-mentioned "wrapping method".

The overlap joint case according to some embodiments of the present invention uses a "shell-like seal" method or a method using separate base plate and cover parts.

According to one embodiment of the invention, the splice case performs a healing and wrapping operation around the cable or other splice when it is exposed to an external heat source, such as a propane flame or hot air. It is treated like this.

Many applications of lap joint cases include cases where the lap joints are located in relatively flat, hard-to-reach areas or are located in hazardous environments, making it very difficult to install the lap joint case. Also included.

For example, when splicing overhead telephone line cables, or when splicing in coal mines or other locations where flammable gases are present, it is often dangerous to use flames to recover the case. Not only can it be avoided, but sometimes it must be avoided at all costs.

Under these circumstances, it would be particularly advantageous for the sewage to avoid the use of external heat, particularly flame, in the installation of the sealing member or splice case.

In a preferred embodiment, therefore, the splice case according to the invention is provided with an integrated heating device.

That is, the lap splice case contains an integrated electrical resistance heating element that, when connected to a suitable power supply, generates heat to rejuvenate the splice case and encapsulate the splice area. It is possible to package it.

This heat recovery lap joint case requires no external heating source;
Instead, it is possible to recover by simply connecting the case to a power source.

In this case, the power source may be, for example, a 12V to 24V battery, or it may be a 115V or other suitable alternating current source, and the case will recover when connected to such a power source and will not disturb the inner surface of the case. The adhesive or sealant is activated.

When preparing the material that provides the integrated heating element used in the spliced case of the present invention, it is important to have a formulation and composition that will provide a uniform heating effect.

In addition, in order to thermally activate the adhesive or sealant using a heating element and at the same time cause thermal recovery of the case, it is necessary to obtain a relatively high temperature of 120°C to 200°C. It is necessary to strictly control the temperature.

In the event of temperatures exceeding the above-mentioned temperature range necessary for thermal recovery of the spliced case and activation of the adhesive, permanent damage may occur to the sealed object, i.e. the spliced case and/or parts of the sealed object. There is sex.

Such damage is often not detectable by visual inspection of the repaired spliced case and the portion of the cable adjacent to the case.

Thermostats and/or other thermal control devices may be employed to control the temperature of the recovering and finished recovering objects.

However, such control often requires expensive, sensitive and/or bulky external actuation for lap joints using self-contained or self-heating seals, often at locations that are difficult to install. A problem arises in that a temperature control device must be provided.

Furthermore, the temperature that can be detected by the control device is limited to the temperature in the immediate vicinity of the device, resulting in the problem that other areas of the case will be at a much lower or higher temperature than the desired temperature. .

Recent new electrical heating applications are considering the use of self-regulating heating devices.

This heating device utilizes a plastic material that exhibits electrical resistance properties with a positive temperature coefficient.

Hereinafter, such temperature characteristics will be referred to as PTC.

Such materials are usually formed from crystalline thermoplastic materials that contain electrically conductive microscopic fillers.

A notable characteristic of these PTC materials is that there is a rapid increase in resistance when a certain temperature is reached.

The temperature at which the resistance increases rapidly in this way is often referred to as the switching temperature Ts.

This is because current tends to stop flowing at this temperature.

This is because the heating element itself or the object being heated by the element can be prevented from further increasing in temperature.

Various theories have been proposed to explain this phenomenon, but the most widely held idea is that PTC
The rapid change in resistance above the crystalline melting point of the material is believed to be caused by the difference in coefficient of thermal expansion between the conductive filler and the thermoplastic material matrix at the melting point.

For a more detailed discussion on the mechanism of PTC phenomena, see for example the article ``Glass transition temperature as a guideline in selecting suitable polymers as rPTC materials'' (J-
Meyers Polymer Engineer
ing in Science, November 1973
Please refer to Monthly (Vol. 13, No. 6).

Most self-regulating heating devices using PTC materials utilize a steep curve R = f (T5) at temperature Ts;
Above this temperature the heating device conducts virtually no current, while below this temperature it exhibits a relatively constant power consumption for a given voltage.

At low temperatures, the electrical resistance of the device remains at a relatively low and constant level, and the current is relatively high for any voltage.

The energy thus generated is dissipated in the form of heat, thereby warming the case material.

The resistance remains at a relatively low level until the temperature reaches Ts, at which point a rapid increase in resistance occurs.

As resistance increases, power consumption decreases and the amount of heat generated is regulated.

In this case, if the curve R-f(7) is very steep, the heating effect is practically stopped.

As the temperature decreases, resistance in turn decreases and power output increases.

Generally speaking, when a voltage is applied to a PTC heating element, the dissipated thermal energy causes the PTC element to rapidly heat up to its switching temperature, after which the temperature rises only slightly due to the rapid increase in resistance. It disappears.

In this case, due to the rapid increase in resistance, the heating element would theoretically reach a steady state temperature near the switching temperature, allowing it to self-regulate its heat output without resorting to means such as fuses or thermostats.

The thermoplastic PTC materials that have been considered by those skilled in the art are extremely crystalline, and the Ts humidity temperature approximately corresponds to the crystal melting point.

However, most such materials actually have a "folding" effect.

That is, the resistance decreases again at temperatures significantly higher than the melting point.

This phenomenon in which the resistance decreases above the melting point is generally undesirable, especially when the PTC material itself is heat recoverable, or when it is brought into close proximity to a heat recoverable material and is heat recoverable. undesirable when used for

This is because, in such situations, the heat-shrinkable material is heated as quickly as possible to its melting point, and then the temperature of the heating device is maintained at a temperature slightly above the melting temperature of the thermoplastic part of the heating device. This is because it is desired to shrink the object quickly and effectively.

However, when the heat-recoverable material used in the present invention is used to encapsulate and seal the lap joints between, for example, telephone line cables from the outside world, adhesives are typically used to attach the lap joints to the cable jacket. A method of shrinking and adhesively bonding the parts is used.

The cable jacket here typically has a partially amorphous, low melting point thermoplastic component, such as a carbon black filled ethylene/vinyl acetate polymer.

Such cable jackets are almost certainly non-crosslinked and therefore will fluidize and easily warp if the jacket temperature rises above its melting point during the heating period to activate the adhesive. It will end up being gone.

Even more serious consequences would occur if a heating device without positive isolation was used and the power source was forgotten to be separated from the heat shrink object.

Under such circumstances, the PTC heating device may be energized for longer than the period required to complete capsule packaging (for example, 10 minutes).

Even more serious consequences occur if each such telephone line cable is insulated with a similar thermoplastic fraction.

Distortion and twisting of the conductor jacket as described above means that that portion of the cable is rendered useless, and is a situation that must be avoided at all costs.

Thus, the desirable characteristics required of a heating device for lap spliced cases are that the resistance increases rapidly and sustainably above the Ts temperature of the heating element, which is somewhat similar to most conventional heating devices. In both cases, the resistance tends to increase until the temperature of the heating element rises above the melting point of the thermoplastic component, without exhibiting the so-called "bending" characteristic in which the steep slope becomes gentle.

Until now, it seems that the above-mentioned "bending" phenomenon and the problems that occur due to this phenomenon have not been widely recognized.

If we think further, we can say the following.

That is, the conductive polymer materials with PTC% properties that have been used up to now are insufficient to cause heat recovery in relatively thick portions of heat recovery materials such as lap joint cases to which the present invention is applied. It has only a radial capacity and an insufficient heat capacity for high temperature adhesive activation as is done in the present invention.

Most of the defects caused by the use of conventional PTC materials in articles such as the lap joint case of the present invention are explained in Japanese Patent Application No. 50-116299 (%855
By using the materials described in Japanese Patent Application No. 50-116270 (Japanese Unexamined Patent Publication No. 51-7664),
This can be overcome by using a structure of the type described in Publication No. 7).

However, although conventional PTC materials are less preferred materials, it is also possible in many cases to use these materials in the lap joint case according to the invention.

When using telephone line cables, it is necessary to exclude moisture, especially if the individual conductors of the cable are coated with paper-based insulation.

This is because if the moisture content contained within the insulation of the wire exceeds a certain relatively low critical level, the electrical properties of the wire will necessarily be severely degraded.

For this reason, a common measure is to insert a paper bag containing a small amount of dehumidifier (usually silica gel) into the splice before the cable is spliced and sealed.

In this case, the amount of dehumidifier in the paper bag is selected to be sufficient to maintain the humidity within the splice at a very low level over the entire life of the splice, regardless of external moisture.

In a typical example, approximately 501 silica gel is used.

As can be expected with methods that use dehumidifiers like this, it often happens that dehumidifiers are forgotten and the paper bag is left unattended and the paper bag is attached to the overlap joint. In extreme cases, undesirable situations may occur, such as a paper bag that has been dropped into water or muddy soil.

According to a preferred embodiment of the present invention, such disadvantages are completely eliminated.

Now, for a more detailed discussion, the performance of paper-insulated cables deteriorates dramatically when humidity becomes extremely high.

Thus, at a relative humidity of 30 φ and an ambient condition of 15° C., the insulation resistance of the paper-insulated stranded wire often used in telephone line cables decreases to about 0.5 gigaohms per IKm length.

Performance is satisfactory at relative humidity below 30 parts.

According to our experimental results, it has been found that it is not necessarily necessary to keep the humidity inside the lap joint case extremely low, and it is sufficient to simply keep it at 30% or less.

In this case, if the dehumidifier is enclosed in a container and the vapor transmission properties of this container are carefully matched to those of the spliced case itself, then the relative humidity inside the spliced case will depend on the humidity outside. However, as shown below, 30
It was also found that it was possible to maintain the temperature below φ.

With 100% relative humidity on the outside of the cable and 0% relative humidity on the inside, a typical splice case according to the present invention has a moisture vapor transfer rate MVT of 100 μg/g at 15°C.
At 100% humidity, the MVT of the dehumidifier container must be at least 100 μg/hour at 30% humidity, and 333 μf at 100% humidity! / It must be thrown for more than 1 hour.

Thus, if the MVT value of the dehumidifier container is 5001 tr/hour, the above conditions can be satisfied.

Now suppose the number of containers above is about 100? , and that the dehumidifier is capable of absorbing approximately 50 f of moisture.

If gold is stored on a shelf at 100% relative humidity and the container is not provided with any other protective cover, the moisture absorption capacity of the dehumidifier in the container will be halved in approximately 6 years.

Thus, if this type of container is permanently fixed inside a spliced case, the protective packaging may be removed during storage of the spliced case and left for many months before use. Even if there were, there would be no substantial reduction in the validity of the case.

A particularly useful feature of the self-heating lap joint cases of the present invention is that these cases can be reused in the future.

If the case is to be reused, simply connect the spliced case to a power source, wait a few minutes for the adhesive to soften, then remove the electrical contacts and clip members (if left) and reassemble the spliced case. All you have to do is separate the upper and lower halves of the split-type stacked and jointed cases.

If desired, after making the necessary modifications to the individual lap joints or changing any of the parts, the entire lap joint case can be reassembled and the adhesive layer removed by briefly connecting it to a power source. It is possible to reactivate and form the case assembly together again without damage.

This ease of reuse means that if the entire cable bundle is not needed during the initial installation, plugs can be used to hold excess cable runs in a stretched state. .

When the aperture case is subsequently reused, additional cables can be added as needed to seal the newly added parts as effectively as the original parts.

Non-self-heating spliced cases can also be reused if the adhesive is remelted using an external heat source.

It is thus a primary object of the present invention to provide a heat recovery closure suitable for encapsulating a plurality of cables of various sizes.

A second object of the present invention is to provide a heat source which can be wrapped around or inserted onto cables and which has a self-heating capacity that can seal such cables without relying on an external heat source. Another object of the present invention is to provide a resilient sealing device.

A third object of the present invention is to provide a self-heating sealing device that is self-adjustable, does not overheat, and shuts off at a temperature lower than a set temperature, without causing permanent damage to the item being encapsulated. It is to provide.

In accordance with the present invention, there is provided a heat recoverable article, such as a spliced case, preferably with a self-contained heating device, which can regulate the heat output without relying on complex temperature control devices. Preferably, a material with a positive temperature coefficient of resistance (PTC material) is provided for smoothing.

The shape of the article is such that it can be placed around a lap splice and sealed by heat recovery.

The term "self-contained heating device" or "self-heating" refers to a lap-jointed case with such characteristics, even if the case is connected to a suitable power source, such as a battery or AC power source. indicates that it contains an electrical resistance heating unit capable of generating sufficient heat to shrink the shrinkable portion and activate (e.g., melt) the adhesive present within the case. .

The present invention also provides a splice case that does not have self-heating properties (i.e., does not have electrical resistance elements), in which case the shrinkage and adhesive activation effects are performed via an external heat source. achieved.

Thus, according to the invention, a heating device is provided which is placed around the joint between long substrates to be coated, seals the joint during heat recovery, and is connectable to and energizable via the power source. In a heat recoverable article comprising: a conductive heating device having a positive temperature coefficient with respect to resistance and capable of heating the article to its heat recoverable temperature when connected to a suitable power source; A heat recoverable article is provided that includes a material formed from a polymeric component.

Preferably, the conductive polymer material exhibits a positive temperature coefficient of resistance, is large in length and width relative to thickness, and is provided in the form of a layer or sheet.

Also, electrodes are provided to pass the current through the thickness of the material, or if the material is in the form of a layer or sheet, from one surface to the other. is preferred.

The heat-recoverable parts of the above articles include materials whose dimensions have changed from a thermally stable shape state, or materials whose dimensions have been formed into a thermally unstable state, both of which become stable when heat is applied. Preferably, it is constructed of a material that can recover to its original shape.

Preferably, at least a portion of the material forming the heating device also forms the thermally dimensionally unstable article portion.

Of course, the characteristics of the particular heating device as well as the materials of construction and electrodes should be determined in each case, taking into account the nature of the power supply available to the user.

The composition of the material is preferably a crystalline polymer, preferably with carbon particles, particularly carbon black, interspersed in the composition.

The polymer composition may be crosslinked by chemical means or by radiation, and the type and proportion of polymer and conductive particles should be determined taking into account the end use and the type of power source available. be.

The surface portions of the article that are in contact with the substrate to be coated, as well as the surface portions that contact each other when the article is placed on the substrate, each have a coating layer of a heat-activated sealant or adhesive thereon. These sealants or adhesives are preferably activated at the recovery temperature of the article.

Preferably, the surface portions that come into contact with each other are provided with a device for holding these surface portions together during the recovery process.

Preferably, the central portion of the article is provided with a thermally stable insert defining a cavity in the lap joint, while the shape of the end portions is coupled to the lap joint. Preferably, it is chosen to recover individually around each of the cables, etc.

The heating device is preferably self-regulating and has two layers:

First layer: the layer has a positive temperature coefficient of resistance and is composed of an electrically conductive polymeric material in surface contact with at least one surface of the layer.

a second layer, the layer having a substantially constant resistance at least up to the recovery temperature of the article so as to provide a substantially constant power dissipation rate at a given voltage; and It is formed from an electrically conductive polymeric material with at least one pair of electrodes.

wherein the pair of electrodes is such that a current passing between the electrodes passes through at least a portion of the constant power consumption rate material;
The first layer is arranged so as to flow from one surface to the other surface.

The first layer is provided with a surface-contact constant power rate layer, and each of the electrodes is in contact with the constant power rate layer.

Preferably, the article includes an insulating layer, which may also be heat recoverable.

In some cases, the articles formed according to the invention can be cured by an external heating device, in which case the conductive layer and electrodes can be omitted.

The invention also provides a method of coating junctions, particularly cable splice junctions, by recovering articles formed according to the invention and junctions coated with the articles.

A self-contained heating device may also be provided with a predetermined voltage (e.g. 12V to 2V from a battery) within its polymeric material.
Preferably, the polymer has a diffusely distributed electrically conductive filler which allows the passage of current at a voltage of 4 V).

In this case, the polymer has sufficient resistance at its operating temperature that the thermal output of the polymer causes a relatively thick section (of the order of a few tones) of the thermally recoverable material to heat up to its recovery temperature. It can be restored around the lap joints to be encapsulated.

In addition, the heating device is preferably adapted to provide sufficient heat output to activate the high temperature thermoplastic or thermosetting adhesive or sealant.

When the shape of the PTC material is large in two dimensions and relatively small in one dimension, such as a sheet layer! Preferably, the incoming current is passed along said small dimension to obtain a uniform heating effect.

If the current flow occurs along the plane of the PTC material layer, a non-uniform heat power distribution will result due to localized heating along specific conductive paths.

When such a malfunction occurs, most of the heating cycle becomes invalid.

If, as a result of local heating, the material exceeds the Ts humidity temperature along a line transverse to the path of the current, it will be impossible for the current to pass further through the path, and eventually a heating device will be formed. The "heat ray" will be effectively cut off until its temperature drops below the Ts temperature.

Paraphrase (f, the above "crossing the material layer between the end electrodes"
The "heat ray" effectively shuts off the heating device even if only a small portion of the surface of the layer reaches Ts.

When such a phenomenon occurs, the heating effect of the heating device becomes extremely insufficient, and in fact, the nuclear heating device appears to have only an extremely small heating capacity.

Such problems can be prevented by disposing the PTC material between the electrodes so that the length of the conductive path where the "hot wire" occurs can be made as short as possible.

In order to obtain maximum efficiency for a minimum current path length, it is necessary to reduce the length to thickness ratio of the material layers.

This condition can be satisfied, for example, by using a sheet material such that the electrodes sandwich the PTC material.

However, due to the short current path length and, in some cases, due to the limited material surface area, there is a risk that such a configuration will result in insufficient heating effects at low inputs of the power source.

In order to eliminate such problems, materials that provide a constant power consumption rate, that is, Joule heat output at a given voltage,
In other words, by laminating a PTC material layer with a material that does not have PTC characteristics, the resulting laminated member has good heating efficiency and can be self-adjusted so as not to generate heat rays.

For a more detailed discussion of the advantages of passing an electric current through the layer rather than along the length of the material and of forming the material in layers, see the above-mentioned Japanese Patent Laid-Open No. 51-76.
Please refer to Publication No. 647.

For a more detailed discussion of PTC materials suitable for use as layer members for use in the present invention, particularly in high temperature applications, please refer to JP 51-60236, supra.
Please refer to the publication No.

Such compositions consist of a mixture of thermoplastic and elastic materials with a diffuse distribution of electrically conductive material therein.

As pointed out herein, such mixtures exhibit a rapid increase in resistance at the melting point of their flammable components, and this increasing trend persists even beyond the melting point temperature. be.

Such a mixture material has the safety feature of further increasing resistance even at temperatures above its melting point, so a heating device using this material can be used at a temperature above the theoretical Ts point.
It is possible to design the device to obtain the effect of switchin, and in this case, there is no risk of thermal damage unlike the design example using conventional PTC material.

Such a heating device, especially a heating device in which the resistance increases extremely rapidly at temperatures above Tss degrees, is extremely "insensitive to commands."

That is, the operating temperature of the PTC material hardly changes due to variations in thermal load.

These heating devices can also be designed to generate extremely high thermal powers up to the point Ts when connected to a power source.

These heating devices have excellent temperature control capabilities that allow the adhesive to be activated and recovered around a substrate, such as a thermoplastic telephone cable jacket, using a heat recovery device such as the one according to the present invention, and to a considerable extent. It can be used to prevent the base body from melting or deforming even if it is left unconnected to a power source for a long period of time.

Various sealing means can be employed for the spliced case, including the adhesive described above.

Such sealing means must also be able to withstand thermal recovery forces at the recovery temperature; see, for example, US Pat. Nos. 3,379,218 and 3,455,336 for such sealing means.

The device and method for encapsulating spliced members according to the present invention are substantially different from conventional devices and methods;
Accordingly, some of the disadvantages inherent in these conventional devices and methods may be overcome or even prevented to some extent.

For example, according to one preferred embodiment of the invention, a thermally recoverable member placed around a substrate, such as a cable, is folded so that its opposing thermally recoverable surfaces do not touch each other and are non-thermally The substrate is wrapped around the substrate in contact with the opposing surfaces of the elongated fingers forming ridges on the corresponding surfaces of the resilient base member.

In some preferred embodiments, the area of the heat-shrinkable member and the heat-stable member that contact each other to define the cavity containing the cable splice is sealed or folded so that it is not itself heat-shrinkable. The joint case is formed by a combination of these two members, and as will be clear from the description below, this feature is significantly different from the conventional technology.

Up until now, when a heat-recoverable member is folded or covered around a base body, the area where the heat-recoverable member is fixed to the sealing member is a mechanically weakened area and resistance to changes in the external environment, such as ingress of water. It has been believed to form a weakened area regarding

The above-mentioned U.S. Pat. No. 3,455,336 solves this problem by providing a folding flap member under the contact end of the heat-recoverable member and securing it to the folding layer via an adhesive to obtain a long leakage path. It describes how to solve it.

However, such a method does not allow the adhesive to fluidize and wet the contact surfaces if the base does not act as a firm base member and the overlying heat-recoverable sealing member presses the flap against the base. It does not work well when it is not possible.

When these drawbacks are added to the difficulty of constructing multiple input splice cases with overlapping thermally recoverable regions, articles constructed according to the '345,336 patent mentioned above. Of course, although useful in most cases, it cannot solve all the problems that the present invention solves.

According to a preferred embodiment of the invention, these Q problems are solved in a very simple and effective manner.

Alternatively, by providing intervening ridges or fingers on the non-heat-recoverable base member in combination with the clips and flanges on the heat-recoverable member, it is possible to easily obtain the above-mentioned desired results. ing.

Referring to the accompanying drawings, FIG. 1 shows a heat-recoverable sealing device constructed in accordance with the present invention, which device is adapted to accommodate a plurality of cables and which includes lap joints between the cables. It has an enlarged central section to accommodate the.

Such a configuration is particularly suitable for low voltage telephone line cable applications where a large number of cables need to be joined quickly, effectively and at low cost.

The device shown in FIG.
Preferably, it includes a self-heating composition as shown in the figures and described in detail below.

Alternatively, the central portion of the spliced case may be non-thermally recoverable and each end portion forming the pleats of the case, i.e. dotted line 1
It is also possible to make only the both end portions of the case shown by 8 heat recoverable.

The layer of heat-recoverable material is crosslinked, for example by the action of radiation, in order to make it heat-recoverable.

The heat recoverable portion, including layer 10, is placed into a stable, unexpanded state with "folds 11" as shown in FIG.

Of course, the unexpanded pleats may have any shape as long as they contain sufficient excess material to allow expansion.

These pleats are expanded via known techniques to a size greater than the diameter of the cable to be sealed, as shown in FIG.

The heat recoverable material has sufficient flexibility and elasticity to allow the cable to be forced into the pleat openings.

As shown in FIGS. 3 and 4, the opening can have different dimensions depending on the size of the cable to be inserted.

Note, however, that it is possible to apply the cable to a wide range of sizes by thermally recovering just one size.

The heat recoverable component 10 is used in combination with a non-heat recoverable lap splice case bottom component 12.

However, this bottom portion may in some embodiments be e.g.
As shown in the figure, it can also be heat recoverable.

The bottom piece 12 can also serve as a permanent attachment to provide rigidity to the cable splice.

Alternatively, the parts 10 and 12 can be provided with cooperating hinges at the end 4 (FIG. 4).

Further alternatively, if parts 10 and 12 are made of the same material, they can be joined together at end 14 by using sealing means at end 6.

Alternatively, the parts 10 and 12 can be separated individually at the ends 14 and 6, in which case the heat-shrinkable part 10 can simply be lifted off the part 12 in order to insert the cable.

If desired, parts 10 and 12 can also be embedded with reinforcing strips along their longitudinal axes, preferably near ends 14 and 6.

Such a strip can also act as a busbar.

To seal a cable splice according to the method of the invention, parts 10 and 12 are first separated and cable 20.
22.24 is inserted.

With particular reference to Figures 2.3.6, in these figures parts 10 and 12 are not integral or hinged, e.g. hinge clamps 52 and 54 are available as clamping devices; The lamp is bolt 5
6 and a wing nut 58.

These clamps can serve to hold parts 10 and 12 during the cable expansion (FIG. 2), insertion and recovery (FIG. 4) processes.

Although such rungs can be formed as permanent parts of the device, these clamps can be removed after attachment of the cape and permanently attached to the ends using adhesives such as those described in U.S. Pat. No. 3,770,556. Preferably sealed.

At the ends it is also convenient to use clamping devices to ensure proper spacing between the cables.

As best shown in FIG. 6, the clamping device may be a plate separator 62 with openings within which the pleats 11 can be accommodated, such plates holding the parts 10 and 12 in place during their expansion. Also, during the sealing operation, the clamps 64 and 66 can provide a firm seal.

In order to provide strength to the lap splice case, protect it, and provide water vapor transmission prevention and radio wave shielding as necessary, the cable lap splice itself is designated by reference numeral 26 in Figure 1 as a separate specification. It is also possible to encapsulate the entire case in a rigid can having a contour defined by dotted lines 18 and 18a located below the central portion of the heat-recoverable member.

If the central portion 26 were heat recoverable, it could conform to the shape of the can.

Conveniently, the layer is made from a rigid material such as metal or molded plastic.

The end openings 19.degree. 21.23 are adapted to accommodate individual cables of different sizes.

The other end of the heat recoverable member typically includes an opening with similar dimensions for receiving the cables to be joined.

Of course, it is also possible to concentrate all the openings on one side.

If a rigid can is used to cover the lap joints, it is not necessary to seal the central portion with a heat recoverable member.

Therefore, as mentioned above, the heat-recoverable portion of the article according to the invention can be limited to only the end portion, so that the article can seal the individual input capules to the can. be.

In this case, the central portion 26 can be made of a non-thermally recoverable material, and even if it is constructed of a heat-recoverable material, it does not need to be cured.

Alternatively, the material may not protrude across the can, leaving the can exposed, or only the insulating layer, such as layers 30-31 in FIG. 5, may protrude from the can, leaving the remaining layers exposed. can also be trapped at the end.

Referring to FIG. 5 in more detail, the heat-recoverable sealing member preferably comprises a self-heating laminate having electrodes embedded therein, the electrodes being connectable to a suitable power source. do.

For details of the above-mentioned laminated member, please refer to the above-mentioned Japanese Patent Application Laid-Open No. 51-116.
Please refer to Publication No. 271.

Briefly, the laminated member is comprised of a thermally recoverable outer insulating layer 30.

The layer 34 comprises a polymer mixture or polymer, such as a mixture of highly crystalline polyolefin and ethylene propylene rubber, within which conductive carbon black is diffused and distributed. ing.

Preferably, layer 34 exhibits a positive temperature coefficient of resistance to control heating effects.

Layer 34 is also preferably folded between layers 32 and 36, which may also be a polymer blend with carbon black diffused therein.

Preferably, these layers exhibit constant power dissipation characteristics for a given voltage over a wide temperature range and do not exhibit an extremely positive temperature coefficient of resistance.

It is also possible to provide an inner insulating layer 31.

Preferably, layers 31, 32, 34, 36 are also heat recoverable.

The inner layer may include an adhesive coating (not shown) on the free surface of the layer for bonding and sealing the cable.

Within the constant power consumption layers 32 and 36 are electrode grids 38 and 4.
0 are embedded, and these electrodes can be connected to a suitable power source, such as a battery as shown diagrammatically in FIG.

With such wiring, current passes from the four poles 38 on the three PTC layers toward the electrode 40.

A more detailed explanation of the preferred structure and shape of the electrode will be given below.

Referring to FIG. 1 in more detail, the layer shows an alternative shape according to the invention.

A member of this configuration can typically be formed from a single sheet of material with layered members as shown in FIG.

After inserting the cable as described above into the opening 44, 46, 48, the device is sealed by pressing the opposite ends 50 together via a suitable sealing member 51.

Such a device can, of course, be constructed to accommodate cables of various sizes as shown.

It should be noted that such a device may be of "shell" construction with a sealing member at 50 and self-hinging means at 47.

A particularly preferred embodiment of the invention is shown in cross section in FIG.

This embodiment includes upper and lower members 96 and 80.

The upper member 96 has an outer spliced case shell 61 secured to the heater, which includes outer and inner layers 68 and 70 of constant power consumption and a core layer 6 of PTC material.
It is formed from 9.

An adhesive layer 11 is fixed to the inner surface of the inner layer 70 .

The PTC core 69 of the heater is preferably manufactured by the above-mentioned Japanese Patent Application Laid-open No. 5160.
It is constructed as described in the '236 publication and is combined with constant power consumption outer layers 68 and 70.

Here, the thermoplastic polymer component of these outer layers is P
It has a melting point lower than that of the thermoplastic polymer component of the TC material.

The constant power consumption layer can be heat recoverable if it comprises a thermoplastic polymer.

Another outer shell 6 also has a layer of heat-recoverable polymeric component having a recovery temperature lower than the melting point of the thermoplastic component of the PTC material.
8 is preferably provided.

Now, it is possible to add a layer 71 of hot-melt adhesive, the melting point of which is close to that of the heat-recoverable material,
The operating temperature is preferably below the melting point of the thermoplastic component of the PTC material.

Such embodiments are particularly suitable for use where the substrate is heat sensitive and will deform or fluidize if heated above its melting point.

As best shown in FIG. 9, embedded within the constant power dissipation layer is a highly flexible electrode T2, preferably formed from stranded wire.

Each heat-shrinkable end pleat has six electrodes 12, three of which are connected to one terminal and three to another.
The electrodes are connected to separate terminals, the electrodes being juxtaposed to each other in pairs and running transversely to the longitudinal axis of the splice case.

The electrode with the first polarity is attached to the busbar electrode 73 through a method such as welding, brazing, or bonding with a conductive adhesive.
and 73a, and the electrodes with the second polarity are connected to busbar electrodes 74 and 74a that run the length of each side of the lap splice case.

Said electrode 73. Each of γ3 a z 74 t 74 a can be formed from stranded wire or thin metal strip.

A tab 7 is provided at the center of one electrode 73 and the center of the other electrode 74a to facilitate connection to a power source.
5 and 16 are fixed.

Attached to the top of the main heat shrink layer (see FIG. 8) is a reinforcing flange 77.78.79 made of a suitable rigid material between the heat recoverable end flap structures.

Such rigid materials may include metals and industrial thermoplastics such as polycarbonates, acrylonitrile butadiene styrene or SAN resins, and filled polymers (such as polyamides and polyolefins).

Among these materials, glass-filled polyamide (nylon) is most preferred.

The non-heat-recoverable lower member 80 preferably has an outer lip 81 to increase stiffness and optionally mate with the open side of the heat-recoverable pleats as shown in FIG. In order to provide the inner ridge 82, the upper and lower members are first brought together and secured by spring clips 83, 84, 85 suitably constructed of a similar material to the flanges 77, 78, 79.

Referring to FIG. 11, there is shown a cross-section along the longitudinal axis of the splice case.

The central cavity 86 serves to accommodate the individual spliced wires of the cable.

This cavity is preferably provided with a small container 95 filled with a dehumidifier, through whose walls moisture diffuses into the container at a faster rate than into the case, as described above. .

A valve may also be provided in the cavity 86 to allow pressure testing of the installed splice case.

With particular reference to the embodiments of FIGS.
A preferred method of manufacturing the lap joint case will be explained with reference to FIGS. 21 to 21.

The electrode material, which is preferably a metal strand, is formed from, for example, 16 carriers, each carrier having four 38
It is possible to form tin-plated copper wire of AWG (equivalent to the diameter of an O, Oi hook in American wire gauge) from wire that has been raised as high as possible (to obtain as much flexibility as possible) and twisted with kneading. Such electrode material is wrapped around a thin conductive wire or non-conductive thermoplastic tube.

With the mari kneading angle set at 75°, the wall thickness is 0.2511an and the outer diameter is 6.25m, which is made of the same components as the above constant power consumption type material.
The best results were obtained by wrapping the material around the tube.

The wire-wound tube is then heated to around the softening temperature of the thermoplastic tube and flattened, taking care not to stretch the wire.

These steps are shown in FIG.

The next step is the formation of polarization, and this step consists of the dub γ5
73a to the side electrodes 73a and attaching the end electrodes 12.

Suitable fixing methods include spot welding, brazing, gluing, etc.

If the electrodes consist of a conductive core made of the same material as the constant power dissipating layer, with a wire around it, a conductive thermoplastic core is used to bond the electrodes together, and thermal bonding is used. Very good results were obtained using the method.

The process of fixing the electrodes together to obtain the basic shape can be facilitated by using a jig such as that shown in FIG.

The materials used for the end electrodes and the above-mentioned stranded wire material to be flattened include woven or plate-shaped metal wires,
Examples include conductive fibers, metal-plated polymer fibers, and polymer fibers containing conductive particles whose fiber direction is highly conductive.

In all of these embodiments, the completed electrode is highly stretchable and provides resistance to the recovery and expansion of the heat recoverable portion of the lap joint case Q during the actual installation or manufacturing of the lap joint case. Preferably, there is no such thing.

Similar materials can be used for the side electrodes.

Since these electrodes do not undergo significant deformations during manufacture and installation, they can also be formed from flat metal or preferably perforated highly conductive strips and single- or multi-stranded wire.

The method of forming the material for the lap joint case is shown in Figure 13 and Figure 1.
This is shown in Figure 4.

The various heating layers can be manufactured, for example, by extrusion or thermal calendering, but it is preferable to assemble these heating layers in a jig frame.

In the illustrated embodiment, the skin layer 61 is first placed in the frame, followed by the constant power consumption layer 68a, the first electrode cella) 73/73a (tab 75 facing to the right as shown in the accompanying figures); Another constant power consumption layer 68b, a PTC control layer 69, yet another constant power consumption layer 70a, a second set of electrodes 74/74a (tab 76 facing left), and a final constant power consumption layer 70b. They are piled up one after another.

The entire structure is then covered with a polytetrafluoroethylene protective layer 97.
They are inserted between them and laminated together by pressure and heating.

A jig is used to hold these various layers and electrodes in place during the stacking process.

When the lamination is completed and the polytetrafluoroethylene layer is removed, the assembled case material is made of foam sheet 100.
It is preferable that the material be inserted between 0 and 100° C. and annealed for a sufficient period of time at a temperature of, for example, 185° C. and a minimum pressure applied, so that each of the constituent layers is completely released from residual stress.

The annealing time may be varied from 2 minutes to 60 minutes depending on the material, but generally an annealing time of about 5 minutes to 15 minutes is preferable.

The blank is removed while it is still held at the annealing temperature and then pressed onto the male mold via pressure in the direction of the arrow as shown in FIG.

Thus, an unexpanded spliced case-shaped member 87 as shown in FIG. 16 is obtained.

In this step, care must be taken to ensure that the heater is not stretched during the molding operation.

If desired, the upper surface of the flange 7778.79 can be provided with a plurality of ridge members, preferably wedge-shaped members, to serve to direct the compressive forces induced by the clamps 83 and 85. .

The splice case 81 is then activated using ion radiation techniques well known in the art to obtain a uniform radiation effect.

Suitable ionic radioactivity includes gamma rays, X-rays, accelerated electron beams, and the like.

The required dose is sufficient to ensure the integrity of the case shape just above the crystalline melting point of the polymeric components of the case, and to suppress the stretching phenomena during the expansion operation that forms the case into a heat recoverable shape. The amount should be chosen so that it is not excessive to the point of interference.

According to the results of experiments, the appropriate irradiation dose was 2 to 50 megarads, preferably 5 to 20 megarads.

After irradiation, the material is in a "thermally stable" shape, which is then formed into a "thermally recoverable" shape 88 in the process shown in FIGS. 17-19. be done.

After preheating article 8T to approximately its crystalline melting point, the forming blank is inserted into jig 89 shown in FIG.

Reinforced flanges 77, 78, 79 with adhesive layers 90 on their contact surfaces are placed on the sides and ends of blank 81 as shown in FIG.

End flange 18 is fitted with a long "snip" tab 91.

The tab 91 has a guide hole 92 for mounting on the jig 89, as shown in FIGS. 1T and 18.

All of the flanges have folded-up lips 98 at their outer ends, which act as ends to protect the heater from mechanical damage.

The side flanges 77 and 19 are provided with a small side plate 99 at the central outer end surrounding the electrode tabs 75 and T6, the dimensions of which are similar to those of standard "quick-release" plates available from Arc-Less, for example. Connector (6,3X
0.8mm).

Pressure is applied to the side and end flanges and the lap joint case pleats to form a central cavity via a suitable stretcher.

Such expansion techniques are well known in the art and include, for example, mandrel expansion and pneumatic or vacuum forming techniques.

Care must be taken during this process to avoid compressing the case pleats longitudinally when using the mandrel.

In order to reduce such a compressive effect, for example, a radially extensible or circumferentially agglomerated sleeve member may be provided between the mandrel and the case pleats, and the sleeve member may be inserted into the pleats via the mandrel. It is possible to adopt a method of dispersing the applied longitudinal force.

Alternatively, the elastic tube may be restrained in the longitudinal direction by pneumatic or hydraulic means.

Preferably, the spliced case cavity is formed pneumatically.

The expandable material is then allowed to cool in a restrained manner as shown in FIG. 19, and then removed from the jig and an adhesive layer 93 is secured to the surface in contact with the lower member as well as to the inner surface of the pleats.

An adhesive layer can also be secured to the contact surface of member 80.

At this stage of the process, if desired, a container 95 filled with dehumidifier may be inserted into the central cavity 95 as shown in FIG.
It can also be fixed to the inner wall.

FIG. 20 shows a view of the completed heat recoverable upper member 96, in which the relative relationship between the case lid and the central cavity can be understood.

Alternatively, the dehumidifier can be fixed to the base plate as shown in FIG.

In use, after the spliced section is completed and assembled into the spliced case, the entire spliced case is assembled by stacking the upper member 96 and lower member 80 on top of each other as described above, and attaching the side clips 83 . 85 and end clips 84a, 84b
They can be assembled by fixing them together using

The heater is then connected to a power source.

The recovery effect is due to the arrangement of the electrodes on the upper member of the spliced case and the relative resistance between the constant power dissipating layer and the PTC layer when these layers are connected to a power source, such as a 12V to 24V complex battery. The heating phenomenon that activates the conduction and/or adhesive will occur primarily in the case pleats and flange areas.

Thus, there is not enough power consumption in the central cavity to heat it sufficiently.

As mentioned above, the composition used in each layer of the heater is selected so that the case can be heated quickly.

For example, using the preferred PTC composition described above, the heater was able to heat the shed area to a temperature of 115-120° C. in less than one minute.

Once such a temperature is reached, the pleat region begins to recover.

In approximately 2 minutes, the pleats shrink around the substrate, such as a cable, and after an additional 8 to 13 minutes, the adhesive layer is fully activated and wets and seals the cable jacket and non-thermally recoverable base member. I was allowed to start.

Thus, in a typical example, the heater is approximately 1
It was connected for between 0 and 15 minutes, during which time the case assembly could be left alone and the operator could perform other tasks.

It will be apparent to those skilled in the art that the heater energization time should be determined by the temperature requirements of the adhesive, the thermal load, and other factors.

According to the experimental results, it was found that the time required for energization is relatively independent of the outside temperature.

The reason for this is considered to be that an extremely sharp blocking effect of the PTσ characteristic was obtained due to the preferable design conditions according to the present invention.

After a suitable period of time, power is removed and the spliced case is allowed to cool to ambient temperature.

The side and end clips may be removed at this point, or alternatively may be left in place to further increase mechanical protection, if desired.

A particular advantage obtained by combining the elements according to the invention is that the heater itself can be maintained within a certain limited temperature range independently of the thermal load of the outside air, so that if this temperature range is Even if the melting point of the thermoplastic cable jacket or individual wire insulation material used is very close, the splice case can be left connected to a power source for a period of, for example, several hours after the cable has been joined. This has the advantage of being possible without causing any damage to the telephone line wires or cables.

In order to facilitate reuse, the heat-recoverable article is provided with a restraining member that prevents the heat-recoverable member from fully recovering when the mounting member is reheated to soften the member and the adhesive. I can do it.

The restraining member may be a rigid tongue, for example made of metal, and these rigid tongues are arranged around the cable.

If you refer to Figure 9, the flat part 1 between the cable input parts
A tongue having a width equal to 8 is positioned on the flat portion, a portion of which projects axially outwardly from the flat portion.

It is possible to place similar tongue members on the outer flat surfaces 77 and 19, all said axially projecting parts being connected to each other via suitably formed connecting links, forming an integral restraining device. can be formed.

This restraint device can be left in place during use if desired.

Preferred embodiments of the heat recovery article of the present invention are listed below: 1. The material constituting the heating means is formed to have a length and width larger than its thickness, and is connected to a power source. The heat recovery article according to claim 1, wherein the electrodes are arranged so that a current flows in the thickness direction of the material when the material is heated.

2. At least the recoverable portion of the article consists of a polymeric material that has been dimensionally changed from a heat-stable shape to a heat-unstable shape and returns or tends to return to the heat-stable shape upon heating; At least a portion of the material of claim 1 or 1. also forms at least part of the material of the electrically conductive polymer composition of the heating device. Heat recoverable article as described.

3. The heating device is self-regulating, the heating device being a layer of a conductive polymer having a positive temperature coefficient of resistance, the polymer material being in flush contact with at least one surface of the layer. a conductive layer having a substantially constant resistance, at least until the recovery temperature of the article is reached, and thus providing a substantially constant power dissipation rate for a given voltage; a second layer of electrically conductive polymeric material and at least one pair of electrodes between which a current flows in at least a portion of the constant power dissipating material and a surface of one of the first layers; and at least one pair of electrodes flowing from one surface to the other. Or 2. The heat-recoverable article described in .

4. Claims having first and second opposing end regions suitable for being abutted to form a generally tubular article and including means for abutting and retaining the regions during recovery. Range 1
Section and above 1. ~3. The heat-recoverable article according to any one of the above.

5. The end region has a heat-activated sealant or adhesive on the abutting surface. Heat recoverable article as described.

6. At least one end of the article is capable of receiving at least two elongated substrates, and means are provided for sealing the ends of the article between the substrates. ~
5. The heat-recoverable article according to any one of the above.

7. 6 above, wherein the end sealing means comprises means for holding together the end facing portions between the substrates. Heat recoverable article as described.

8. The heat recovery article as described in 2 above, wherein the opposing portion holding means comprises a clip or a clamp.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a first embodiment of a heat recoverable article or lap joint case formed in accordance with the present invention; FIG. Figure 3 is an end view of the article before it expands into an unstable shape, that is, a thermally recoverable shape; Figure 3 is an end view of the article after it has been expanded into a thermally unstable shape; Figure 5 is a cross-sectional view along line 5-5 in Figure 3 showing details of the layered structure of the article; Figure 6 is an end view of the article after it has been heat-recovered around the cable; A perspective view of the article; FIG. 1 is a perspective view of an alternative embodiment of an article constructed according to the invention; FIG. 8 is a sectional view of one end of the spliced case; FIG. 9 shows details of the case. FIG. 10 is a perspective view of the lap joint case viewed from the non-thermal recovery base member; FIG. 11 is a longitudinal sectional view of the lap joint case showing details of the internal cavity; FIG. FIG. 12 is a diagram showing the structure of a preferred stranded wire electrode, FIG. 13 is a diagram showing the arrangement of the electrodes on the bus bar,
Fig. 14 is a partially cut-away view showing the various layers obtained when the material for the heat-recoverable member is placed in a jig prior to the lamination operation, and Fig. 15 is a partially cutaway view of the heat-recoverable member material. FIG. 16 is a diagram showing the state in which the material is molded into a basic shape. FIG. 16 is a diagram showing the heat-recoverable member formed into a thermally stable shape through a crosslinking process. FIG. 11 is a diagram showing the above-mentioned heat-recoverable member. Figure 18 shows the structure of the reinforced 7-lunges on the ends and sides of the heat-recoverable member, in which the heat-recoverable member is placed in a jig prior to its expansion process, and the reinforced 7-lunges are attached to the member. 19 is a diagram showing the heat recovery member at the end of the expansion stage; FIG. 20 is a perspective view of the upper and lower members of the case to show internal details of the case; FIG. 2
Figure 1 shows a particularly preferred embodiment shown after installation around a cable splice. 12: Lap joint case, 26: Heat recovery member, 34: P
TC material layer, 30, 31: insulating layer, 38° 40: electrode,
10 = constant power consumption rate layer, 71 = adhesive layer.

Claims (1)

[Claims] 1. A heating device placed around the joint between the long substrates to be coated, sealing the joint during heat recovery, and comprising a heating device connectable to and energized via the power source. a heat recoverable article comprising a conductive polymer component having a positive temperature coefficient with respect to resistance and capable of heating the article to its heat recoverable temperature when connected to a suitable power source; A heat recoverable article comprising a material formed from. 2. A method for covering a bonded portion between substrates, comprising placing the heat-recoverable article according to claim 1 on the bonding portion, and optionally applying edge contact holding means to the edge of the article. placing an edge retaining means in a suitable position over the area and at least one of said edges, connecting said heating device to a power source and continuing this connection until the article is restored onto the joining part; A method comprising.