JP6299048B2 - Heat shrink tube and heat shrink cap - Google Patents

Description

  The present invention relates to a heat-shrinkable tube and a heat-shrinkable cap used for waterproofing wire harnesses for automobiles.

  Wire harnesses for automobiles and motorcycles are made by combining multiple insulated wires with cable ties and adhesive tape, etc. Each wire is made of a wire made of a conductor such as a copper alloy (usually a plurality of wires). The bundle is covered with an insulator. The connection part (joint part) at the end or middle part of the wire bundle such as a wire harness is a part where the strands are exposed, and its inner surface is covered with a hot melt adhesive (inner layer adhesive) A heat-shrinkable tube having a layer and a heat-shrinkable cap are used.

  As a waterproof requirement for wire harnesses, not only the entry of water from the outside at the connection site, but also the internal gaps in the strands to prevent the intrusion of water entering the insulated wire from the non-waterproof site Water stoppage (water resistance between strands) is often required. The reason for this is that water travels through the inside of the electric wire and even water enters important equipment. However, since the viscosity of the inner layer adhesive of the conventional heat shrinkable tube and heat shrinkable cap is high, the inner layer adhesive does not penetrate between the strands by simply covering the strands with the heat shrinkable tube and cap. Aqueous cannot be obtained.

  Therefore, in order to obtain a sufficient water-stop property between the strands, conventionally, before shrinking the heat-shrinkable tube or cap, a thermosetting resin such as an epoxy resin is used to immerse the connecting part in an adhesive having a low viscosity. Work such as pouring between the strands and curing is performed.

  For example, Patent Document 1 discloses a method in which a gap between terminals of a plurality of electric wires is narrowed by tape winding or the like, and a cyano-based adhesive is permeated and solidified in a gap between core wires of the portion to bond the core wires together. In addition, a waterproof structure for an electric wire terminal is described in which a heat-shrinkable tube having a hot melt layer (adhesive layer) on its inner surface is placed on the terminal, and the hot melt layer is melted and solidified for filling. Further, Patent Document 2 includes a water-stopping material supply step in which a liquid water-stopping material having thermosetting properties is attached to a terminal core wire portion where a plurality of covered electric wires are exposed, and the water-stopping material penetrates between the core wires. A water-stopping material curing step for hardening the water-stopping material with heat generated by resistance welding, and a heat shrink cap coated with hot melt on the inside is put on the end of the covered electric wire, and heat is applied to the heat shrink cap. A joint water-stopping method that sequentially includes a line water-stopping step of shrinking a heat-shrinkable cap and allowing the hot melt to permeate between the covered wires to stop water between the covered wires. .

JP-A-11-233175 JP 2009-99385 A

  As described above, in the conventional method, in order to achieve not only the waterproof part but also inter-strand water stop, at least the work for inter-strand water stop and the work of covering and shrinking with a heat-shrinkable tube or cap. Two operations were required, and there was a problem with productivity. Therefore, there has been a demand for a method capable of waterproofing the waterproof portion and stopping the water between the strands only by performing heat shrinkage by covering with a heat-shrinkable tube or cap.

  The present invention is a heat-shrinkable tube or heat-shrinkable cap used for waterproofing an exposed portion of an electric wire such as a connection portion of an electric wire bundle formed by bundling a large number of insulation-coated electric wires such as an automobile wire harness. It is an object of the present invention to provide a heat-shrinkable tube and a heat-shrinkable cap that can be covered and waterproofed together with the waterproofing of the exposed portion of the electric wire simply by applying heat shrinkage. Another object of the present invention is to provide a method for waterproofing a wire bundle that can achieve waterproofing of the exposed wire portion as well as inter-wire waterproofing simply by covering the exposed wire portion with a heat-shrinkable tube or heat-shrinkable cap and performing heat shrinkage. Let it be an issue.

  A first aspect of the present invention is a heat-shrinkable tube or heat-shrinkable cap having an adhesive layer in contact with its inner surface, and collapses by heating when the tube or cap is heat-shrinked in the tube or cap. In the capsule, an adhesive for inter-wire penetration that becomes a liquid with a viscosity lower than that of the adhesive forming the adhesive layer by heating and solidifies after thermal contraction of the tube or cap is formed in the capsule. A heat shrink tube or heat shrink cap that is filled.

  According to a second aspect of the present invention, there is provided a waterproofing method for an exposed wire portion of an electric wire bundle formed by bundling a plurality of insulation-coated electric wires, wherein the exposed wire portion is in contact with an inner surface thereof and has an adhesive layer. After the tube or heat-shrink cap is put on, the method comprises heating and heat-shrinking the tube or cap, and the tube or cap includes a capsule that collapses by heating when heat-shrinking, Is a method for waterproofing an electric wire bundle that is filled with an adhesive for inter-element penetration that becomes a liquid with a viscosity lower than that of the adhesive forming the adhesive layer by the heating and solidifies after heat shrinkage.

  According to the first aspect of the present invention, the bare wire (conductor) exposed portion of the wire bundle, that is, the waterproof portion of the exposed wire (conductor) exposed portion is covered with the waterproof portion of the bare wire (conductor) exposed portion by simply covering the exposed portion. A heat-shrinkable tube or heat-shrinkable cap that can also stop water is provided.

  According to the second aspect of the present invention, the exposed wire (conductor) of the wire bundle, that is, the portion where waterproofing is required, is covered with the heat-shrinkable tube or the heat-shrinkable cap, and the wire (conductor) is simply contracted by heating. ) Provided is a method for waterproofing a bundle of wires that can waterproof an exposed portion and can also stop water between strands. Therefore, this waterproofing method is highly productive and can be preferably applied as a waterproofing method for connecting parts of automobile wire harnesses.

It is a schematic cross section showing an example of the heat contraction tube and heat contraction cap of the 1st mode. It is a schematic cross section showing other examples of the heat contraction tube and heat contraction cap of the 1st mode. It is a schematic cross section which shows 1 process of the method of waterproofing the electric wire exposure part of a wire harness by a 2nd aspect. It is a schematic cross section which shows 1 process of the method of waterproofing the electric wire exposure part of a wire harness by a 2nd aspect.

  Hereinafter, the form for implementing about a 1st aspect and a 2nd aspect is demonstrated based on a specific example. The inventions of the first aspect and the second aspect are not limited to these forms and specific examples, but are shown by the scope of claims and within the meaning and scope equivalent to the scope of claims. All changes are included.

  As a result of intensive studies to solve the above-mentioned problems in the waterproofing method for electric wire bundles using a conventional heat-shrinkable tube or cap, the present inventor has found that the heat-shrinkable tube or cap has an adhesive layer formed on the inner surface. In addition, a capsule that is stable during storage but disintegrates due to the heating temperature when the tube or cap is heat shrunk is provided, and the capsule has a low-viscosity liquid that penetrates between the wires of the wire bundle due to heating during heat shrinkage. In addition, the inventors found that the above-mentioned problems can be solved by filling an adhesive for inter-element penetration that solidifies after heat shrinkage, and completed the inventions of the first and second aspects.

(1) Heat-shrinkable tube or heat-shrinkable cap of the first aspect A first aspect of the present invention is a heat-shrinkable tube or heat-shrinkable cap having an adhesive layer in contact with the inner surface thereof, wherein the tube or cap Including a capsule that disintegrates by heating when the tube or cap is thermally shrunk, and the capsule becomes a liquid having a viscosity lower than that of the adhesive forming the adhesive layer by the heating. A heat-shrinkable tube or a heat-shrinkable cap filled with an adhesive for inter-element penetration that solidifies after heat-shrinking of the cap.

  The heat-shrinkable tube in the first aspect and the second aspect is a tube having a property of shrinking in the radial direction by heating, and the both ends of the heat-shrinkable tube are normally open, and the electric wire exposed portion at the end of the wire harness is waterproofed. Although the thing used for the above is said, it may be called a heat shrinkable tube including the following heat shrinkable caps. The heat-shrink cap is a heat-shrinkable tube whose one end has already been closed by heat-shrinkage or the like, and is used for waterproofing the exposed wire portion at the end of the wire harness.

  The heat-shrinkable tube and heat-shrinkable cap of the first aspect are configured using the same resin as that of the conventional heat-shrinkable tube, and can be manufactured by the same method. For example, after a linear polyolefin polymer is formed into a tube shape using a melt extruder, etc., the resin is cross-linked by ionizing radiation irradiation, etc., and then the diameter is expanded by a method such as sending compressed air into the tube, and then cooling and fixing. Thus, a resin tube having heat shrinkability can be manufactured. The heat shrink cap can be manufactured by closing one end of the heat shrink tube manufactured as described above by heat shrink or the like.

  The heat-shrinkable tube and heat-shrinkable cap of the first aspect are provided with an adhesive layer formed by an adhesive resin (inner layer adhesive) having adhesiveness to the adherend in contact with the inner surface thereof. With this adhesive resin, the heat-shrinkable tube and the heat-shrinkable cap are bonded to the insulated wires (including the exposed wire portion) constituting the wire bundle, and the exposed wire portion is waterproofed. The adhesive resin has fluidity at the heat shrinkage temperature and solidifies after cooling to adhere the exposed wire portion, and a thermoplastic resin is preferably used. When the adhesive layer is composed of a thermoplastic resin, there is no limitation on the usable time. Examples of the adhesive resin include hot melt adhesives such as thermoplastic polyester resins, polyamide resins, and polyolefin resins.

  The heat-shrinkable tube or heat-shrinkable cap of this aspect includes a capsule that collapses at a heating temperature when the tube or cap is heat-shrinked. The capsule maintains a stable capsule shape at a temperature at which the heat-shrinkable tube and heat-shrinkable cap are stored, but collapses at a temperature at which the tube or cap is heat-shrinked. Therefore, the temperature at which the capsule collapses must be lower than the temperature at which the tube or cap is thermally shrunk (heat shrink temperature). However, if the temperature at which the capsule collapses is too low, it is difficult to maintain a stable capsule shape during storage. There is a case.

  Therefore, in order to reliably collapse the capsule at the time of heat shrinkage and to maintain a stable capsule shape at the time of storage, specifically, a capsule that collapses at a temperature lower by 5 to 30 ° C. than the heat shrinkage temperature is preferable. The capsules are also required to have mechanical strength to maintain a stable capsule shape during storage of the heat shrink tube or heat shrink cap.

  As a material for forming the capsule, a thermoplastic resin that decomposes or melts at a heating temperature can be used. The capsule size is preferably 50% or less of the inner diameter of the heat-shrinkable tube. When the diameter of the capsule is large, the capsule is inserted into the heat shrinkable tube or heat shrinkable cap so that the position of the capsule can be maintained. When the diameter of the capsule is small, it can be inserted into a heat shrinkable tube or heat shrinkable cap as a ring-shaped tube in which the capsule is hardened with a binder or the like.

  In the capsule, at the heat shrinkage temperature, it becomes a liquid having a lower viscosity than the adhesive forming the adhesive layer and penetrates between the strands, and solidifies when cooled after the heat shrinkage and can stop water between the strands. Filled with adhesive for inter-element penetration. Here, osmosis between the strands of the wire bundle means that it penetrates between the plurality of insulated wires constituting the wire bundle and also penetrates between the strands constituting the conductor inside each insulated wire. Means.

  Accordingly, the inter-element penetration adhesive filled in the capsule has a low viscosity so as to penetrate between the wires of the wire bundle at the heat shrink temperature. On the other hand, when cooled after heat shrinkage, it is desirable to solidify so as to obtain a sufficient water-stop property between strands. The adhesive resin that constitutes the adhesive layer formed in contact with the inner surface of the tube or cap does not usually have a low viscosity that penetrates between the wires even at the heat shrink temperature. It is not possible to obtain water resistance between strands with resin alone. However, in the first aspect, since the interpenetrating adhesive filled in the capsule penetrates between the strands of the electric wire bundle due to the collapse of the capsule and solidifies after cooling, sufficient strands are obtained. Intermittent water is obtained.

  Specific examples of the inter-element penetrating adhesive filled in the capsule include the following.

a) Adhesive made of a thermoplastic resin having a large viscosity change with temperature In other words, at a temperature at which a bundle of wires stopped by a heat-shrinkable tube or heat-shrinkable cap is used, a sufficient water-stop property between wires is obtained. Although it is solidified, it is a thermoplastic resin having a low viscosity that can penetrate between the wires of the wire bundle at the heat shrink temperature. Therefore, at the heat shrink temperature, the viscosity is much lower than that of the adhesive resin constituting the adhesive layer. Therefore, as a more preferable embodiment of the first embodiment, the inter-element penetration adhesive has a low viscosity that can penetrate between the wires of the wire bundle at the heat shrinkage temperature and is solidified by cooling after heat shrinkage. A heat shrink tube or heat shrink cap that is a resin is provided. Examples of such thermoplastic resins include polyamide resins and ethylene-vinyl acetate resins.

b) Adhesive that comes into contact with air after capsule disintegration and cures by moisture or the like. This resin has a low viscosity that can penetrate between the wires of the wire bundle before curing. This resin is filled in the capsule when the heat-shrinkable tube or heat-shrinkable cap is stored, but flows out due to the collapse of the capsule during heat-shrinkage and penetrates between the electric wires (element wires). Thereafter, it is cured by moisture in the air and the like to achieve a sufficient water-stop property between wires. Examples of such an adhesive include a cyano adhesive and a moisture curable polyurethane resin.

c) Adhesive made of thermosetting resin This resin also has a low viscosity that can penetrate between the wires of the wire bundle before curing, and is filled in the capsule. By heating for heat shrinkage, the capsule collapses and penetrates between the electric wires (wires), and is thermoset to achieve sufficient water resistance between the wires. Examples of such an adhesive include an epoxy resin, a phenol resin, and a thermosetting polyester resin.

d) Adhesive made of a curing agent and a resin that is cured by the curing agent The curing agent and the resin that is cured by the curing agent have a low viscosity that penetrates between the wires of the wire bundle at the heat shrink temperature. The curing agent and the resin are filled in separate capsules and do not mix with each other before the capsule collapses. When the capsule collapses due to heating for heat shrinkage, the capsule penetrates between the electric wires, and the curing agent and the resin are mixed and cured, thereby achieving sufficient inter-element water blocking properties. Examples of such an adhesive include a combination of an epoxy resin and its curing agent, an amine, a polyamide resin, an acid anhydride, and the like. Therefore, as a more preferable aspect of the first aspect, a heat-shrinkable tube or a heat-shrinkable cap is provided in which the inter-wire penetration adhesive is made of an epoxy resin and its curing agent.

  The amount of the capsule contained in the heat-shrinkable tube or heat-shrinkable cap of the first aspect is such that the interstrand penetration adhesive filled in the capsule is sufficient to achieve inter-strand waterproofing. It is. In addition to the above, a curing accelerator, a stabilizer, an antioxidant and the like can be added to the heat-shrinkable tube or heat-shrinkable cap as needed, as long as the spirit of the invention is not impaired.

(2) About waterproofing method of electric wire bundle of 2nd aspect The 2nd aspect of this invention is a waterproofing method of the strand exposed part of the wire bundle formed by bundling a plurality of insulation covering electric wires, Comprising: The said strand exposure A heat shrinkable tube or heat shrinkable cap having an adhesive layer in contact with the inner surface of the portion, and then heat-shrinking the tube or cap with heat, and the tube or cap is thermally shrunk. A capsule that collapses due to the heating temperature at the time, and in the capsule, due to the heating, it becomes a liquid having a lower viscosity than the adhesive forming the adhesive layer, and for interfilament penetration that solidifies upon cooling after heat shrinkage This is a method for waterproofing a bundle of wires filled with an adhesive.

  According to the waterproofing method of the second aspect, the wire exposed portion is covered with a heat shrinkable tube or heat shrinkable cap, and the tube or cap is heat shrunk by heating. It can also stop water between strands. Therefore, the productivity of waterproofing work for wire bundles such as wire harnesses can be enhanced as compared with the prior art.

  In the waterproofing method of the second aspect, a heat shrinkable tube or heat shrinkable cap having an adhesive layer in contact with the inner surface thereof, including a capsule that collapses by heating when heat shrinking is contained, A heat-shrinkable tube or heat-shrinkable cap filled with an inter-wire penetration adhesive that becomes a liquid with a lower viscosity than that of the adhesive forming the adhesive layer upon heating and solidifies upon cooling after heat-shrinking, that is, the present invention. The heat-shrinkable tube or heat-shrinkable cap of the first aspect is used.

  In the waterproofing method of the second aspect, first, a heat shrinkable tube or a heat shrinkable cap is put on the wire exposed portion of the wire bundle. A wire bundle to which this waterproofing method is applied is a bundle of a plurality of wires (conductor wire, core wire: usually composed of a plurality of strands) coated with an insulating resin. In particular, a wire harness for automobiles can be cited as a representative example. Therefore, as a more preferable aspect of the second aspect, there is provided a method for waterproofing an electric wire bundle in which the electric wire bundle is an automobile wire harness.

  The strand exposed portion of the electric wire bundle is a portion where the conductor is exposed by removing the insulation coating formed at the connection part or branching portion of the electric wire bundle. In the branch portion, an exposed portion of the wire is provided in the middle portion of the wire bundle, and a heat shrinkable tube having both ends opened is often used for waterproofing / waterstop of this portion. The connection part is often provided with a bare wire exposed portion at the end of the wire bundle, and a heat shrink cap, which is a heat shrink tube with one end closed, is often used for waterproofing and water stopping of this part.

  After the exposed wire portion is covered with the heat shrinkable tube or the heat shrinkable cap, the heat shrinkable tube or the heat shrinkable cap is heated to the heat shrinkage temperature. Heat shrinks the heat-shrinkable tube or heat-shrinkable cap by heating, and the adhesive (inner layer adhesive) that forms the adhesive layer flows and covers the bundle of insulated wires in the exposed part of the wire from the outside. Waterproofing of the exposed wire portion is achieved by solidifying the agent. However, since the inner layer adhesive has a relatively high viscosity even at the heat shrink temperature, it does not sufficiently penetrate between the insulated coated electric wires, between the insulated coating and the conductor, particularly between the plurality of strands constituting the conductor. That is, sufficient inter-strand water resistance cannot be obtained with the inner layer adhesive alone.

  By heating to the heat shrink temperature, the capsule in the heat shrink tube or the heat shrink cap collapses, and the inter-wire penetration adhesive filled in the capsule flows out. The adhesive for penetration between strands has a viscosity lower than that of the inner layer adhesive at the heat shrinkage temperature, and becomes a liquid having a viscosity capable of penetrating between the insulating coating and the conductor or between the strands. As a result, it penetrates between the insulation coating and the conductor or between the strands.

  After the inter-element penetration adhesive penetrates between the insulation coating and the conductor or between the strands (inter-element penetration), the inter-element penetration adhesive is cured. And sufficient water resistance between strands can be achieved.

  When the inter-element penetration adhesive is made of a thermoplastic resin having a large viscosity change due to temperature (the above-mentioned a)), the curing is performed by cooling the inter-element penetration adhesive after heating. When the inter-element penetration adhesive is in contact with air and is cured by moisture or the like (b), the curing is performed by contacting the adhesive with the air after penetration between the strands. . In the case where the inter-element penetration adhesive is made of a thermosetting resin (the above c)), the adhesive is cured by heating to the heat shrinkage temperature after penetration between the strands. When the adhesive for interstrand penetration is made of a curing agent and a resin that is cured by the curing agent (above d)), the capsule is collapsed by heating to the heat shrink temperature, and the curing agent and the resin are mixed and cured. It is cured by reacting.

  Next, the heat-shrinkable tube, the heat-shrinkable cap of the first aspect, and the waterproofing of the wire harness using these will be described with reference to the drawings (that is, the second aspect).

  Fig.1 (a) is a schematic cross section showing an example of the heat contraction tube of a 1st aspect, FIG.1 (b) is an example of the heat contraction cap of a 1st aspect. Both represent the state before heat shrinkage. In the figure, 1 represents a heat shrinkable tube or heat shrinkable cap (resin part), and 2 represents an adhesive layer (internal adhesive layer) formed on the inner surface of the heat shrinkable tube or heat shrinkable cap. The heat shrink cap of FIG. 1 (b) is obtained by heat shrinking one end of the heat shrink tube of FIG. 1 (a).

  1 in FIG. 1 (a) (b) represents the resin layer with a capsule. 1A and 1B show a case where the diameter of the capsule is small, and the capsule 5a is dispersed in the encapsulated resin layer 3. FIG. The encapsulated resin layer 3 may be formed by forming a ring-shaped tube in which a capsule is hardened with a binder, and inserting the tube into a heat-shrinkable tube or a heat-shrinkable cap. In this case, the binder is a resin constituting the encapsulated resin layer 3.

  The capsule 5a is filled with a strand penetration adhesive. Capsule 5a collapses due to heating during heat shrinkage. Since the strand-penetrating adhesive has a low viscosity at the temperature of heat shrinkage, the strand-penetrating adhesive of the capsule 5a that has flowed out due to the collapse penetrates between the strands.

  FIG. 2A is a schematic cross-sectional view showing another example of the heat-shrinkable tube according to the first aspect, and FIG. 2B is another example of the heat-shrinkable cap according to the first aspect. 1 (a) and 1 (b), 1 represents a heat shrinkable tube or a heat shrinkable cap (resin part), and 2 represents an adhesive formed on the inner surface of the heat shrinkable tube or heat shrinkable cap. Represents a layer (interior adhesive layer). Moreover, the heat shrink cap of FIG. 2B is obtained by heat shrinking one end of the heat shrink tube of FIG.

  1A and 1B show the case where the capsule diameter is small, while FIGS. 2A and 2B show the case where the capsule diameter is large. 2 in FIGS. 2A and 2B represents a capsule adhesive layer. When the diameter of the capsule is large, the capsule 5b is held by the capsule adhesive layer 4 because the capsule cannot be dispersed in the resin layer. That is, the capsule 5b is held on the inner surface of the heat shrinkable tube or the heat shrinkable cap by an adhesive. As long as the capsule is held, it may be held by a method other than the capsule adhesive layer.

  3 and 4 are schematic cross-sectional views showing one step of a method of waterproofing the exposed wire portion 8 of the wire harness 7 according to the second embodiment, using the heat-shrinkable tube shown in FIG. It is. As shown in the figure, the exposed wire portion 8 of the wire harness 7 is inserted into the heat shrinkable tube, and the heat shrinkable tube 1 is heated and thermally contracted. FIG. 3 shows the stage being heated before heat shrinking, and FIG. 4 shows the stage after heat shrinking.

  Similar to the capsule 5a, the capsule 5b is filled with the adhesive 6 for strand penetration. Capsule 5b collapses due to heating during heat shrinkage. Since the strand-penetrating adhesive 6 of the capsule 5b has a low viscosity at the temperature of heat shrinkage, it flows out from the collapsed capsule 5b and penetrates between the strands. Since the strand-penetrating adhesive 6 has a high viscosity at low temperatures, it is solidified by cooling after heat shrinkage, and a sufficient water-stop property between strands is obtained. Even in the case of a heat-shrinkable cap or in the case where the capsule diameter is small as shown in FIGS. 1 (a) and 1 (b), it is sufficient as in the case described in FIGS. Inter-strand water resistance is obtained.

(Reference experiment example)
[Material used in the experiment]
1. Heat Shrink Cap: Heat Shrink Cap A 10/4 × 70 L (Material: Polyethylene inner diameter before shrinkage 10 mm, thickness before shrinkage 0.65 mm, inner diameter after shrinkage 4 mm, thickness after shrinkage 1.5 mm, length 70 mm)
2. Wire harness: Electric wire AVSS0.5 (conductor: annealed copper strand insulator: vinyl chloride, number of strands, strand diameter 0.32mm, conductor cross section 0.56mm, manufactured by Sumitomo Wiring Systems) 7 by ultrasonic welding 2. Jointed Adhesive (1) Aron Alpha 201 (α-cyanoacrylate, viscosity (25 ° C.): 2 cp, manufactured by Toagosei Co., Ltd.)
(2) JER827 (epoxy resin, epoxy equivalent: 180-190, viscosity (25 ° C.): 9000-11000 cp, manufactured by Mitsubishi Chemical Corporation)
+ Curezol 1B2PZ (1-benzyl-2-phenylimidazole, epoxy resin curing agent, manufactured by Shikoku Chemicals)

Experiment 1 (example not using adhesive for inter-wire immersion)
After inserting the exposed wire portion at one end of the wire harness into the heat shrink cap, the heat shrink cap was heat shrunk by heating at 150 ° C. for 5 minutes. After cooling, the end was immersed in water, 0.2 MPa of compressed air was introduced from the other end of each of the seven electric wires constituting the wire harness, and an air leak test was performed, but an air leak occurred.

Experiment 2
Aron Alpha 201 was used as an adhesive, and 0.2 g thereof was put into the heat shrink cap, and then one end of the wire harness was inserted into the heat shrink cap and heated at 150 ° C. for 3 minutes to heat shrink the heat shrink cap. After cooling, the end was immersed in water, 0.2 MPa of compressed air was introduced from the other end of each of the seven wires constituting the wire harness, and an air leak test was performed, but there was no air leak. The viscosity of Aron Alpha 201 at a normal shear rate of 1 s ⁻¹ was 2.0 Pa · s.

Experiment 3
The test was conducted in the same manner as in Experiment 2 except that JER827 + Curazole 1B2PZ was used as the adhesive and the heat shrink heating condition was 150 ° C. × 10 minutes, but there was no air leakage. The viscosity of JER827 at a shear rate of 1 s ⁻¹ at 150 ° C. was 1.0 Pa · s or less.

From the above results, the following can be said.
1. When the adhesive for interpenetration between wires is not used (Experiment 1), inter-wire waterstop is not obtained.
2. When a low-viscosity adhesive at 150 ° C. is used as the inter-element penetration adhesive (Experiments 2 and 3), one end of the wire harness is placed in a heat-shrink cap in which the inter-element penetration adhesive is previously placed. Sufficient inter-strand water resistance is obtained by the method of inserting the part and heat shrinking (that is, the process of not immersing the end of the wire harness in the adhesive before inserting the one end of the wire harness into the heat shrink cap). It has been.

  The above results are considered to be the same even when an adhesive having a low viscosity at 150 ° C. is filled in a capsule that disintegrates at 150 ° C. or less and placed in a heat shrink cap. And the storage stability of an adhesive agent also improves by filling a capsule. Therefore, according to the present invention, a heat-shrinkable tube, a heat-shrinkable cap, and an electric wire using the heat-shrinkable tube and the heat-shrinkable cap that can waterproof the wire-exposed portion and stop water between the strands simply by covering the wire-exposed portion with heat shrinkage. It can be said that the result of the experiment shows that a bundle waterproofing method is provided.

DESCRIPTION OF SYMBOLS 1 Heat shrinkable tube, heat shrinkable cap 2 Adhesive layer 3 Capsule resin layer 4 Capsule adhesive layer 5a, 5b Capsule 6 Wire penetration adhesive 7 Wire harness 8 Electric wire exposed part

Claims (5)

  A heat-shrinkable tube or heat-shrinkable cap having an adhesive layer in contact with the inner surface thereof, the capsule containing the capsule that disintegrates by heating when the tube or cap is heat-shrinked. Is a heat-shrinkable tube or heat filled with an inter-wire penetrating adhesive that becomes a liquid with a lower viscosity than the adhesive forming the adhesive layer due to the heating and solidifies after heat-shrinking of the tube or cap. Shrink cap.   2. The heat shrinkable tube according to claim 1, wherein the inter-wire penetration adhesive is a thermoplastic resin that has a low viscosity that can penetrate between the wires of the wire bundle at a heat shrinkage temperature and is solidified by cooling after heat shrinkage. Or heat shrink cap.   The heat-shrinkable tube or heat-shrinkable cap according to claim 1, wherein the inter-element penetrating adhesive comprises an epoxy resin and a curing agent thereof.   A method for waterproofing a wire exposed portion of a wire bundle formed by bundling a plurality of insulation-coated wires, wherein the wire exposed portion is covered with a heat shrinkable tube or heat shrinkable cap having an adhesive layer in contact with the inner surface thereof And the step of heat shrinking the tube or cap, the tube or cap includes a capsule that collapses by heating when heat shrinking, and the capsule contains the adhesive by the heating. A method for waterproofing a bundle of wires, which is filled with an adhesive for inter-wire penetration that becomes a liquid having a lower viscosity than the adhesive forming the layer and solidifies after heat shrinkage. The method of waterproofing an electric wire bundle according to claim 4 , wherein the electric wire bundle is an automobile wire harness.

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