JP2802619B2 - Coating material for conductor connecting portion and coating method therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a covering material for covering a connecting portion of a conductor such as an electric wire and a lead wire, and a covering method thereof. (Prior Art) For example, automotive wire harnesses include a main harness, a side harness, an engine sub-harness, a rear harness, a door harness, an instrument harness, and the like. Harnesses). The connecting part of the harness as a conductor is waterproof and protected with a covering material to prevent metal corrosion due to water intrusion and salt damage and adverse effects such as poor electrical connection and disconnection. ing. Conventional coating materials and methods of using the same include the following. Vinyl tape: Wrap around the joint. Thermoplastic resin: a; Molded by the extrusion molding method and simultaneously solidified in the connecting portion to seal the connecting portion. b; Formed into a sheet and thermocompression bonded to the connection. c; sealing is performed by injecting a heat-meltable resin into the container into which the connecting portion is inserted. Heat-shrinkable tube: After passing the connection portion of the lead wire through the heat-shrinkable tube, a certain temperature is applied from the outside of the tube to shrink the tube. (Problems to be Solved by the Invention) However, when the connecting portion of the conductor is covered with the above-mentioned covering material, there are the following disadvantages. Since the winding of the conductor around the connecting portion must be performed manually, it is troublesome and the productivity is low. a; The equipment becomes larger due to the need for an extrusion molding machine and the like. b; Poor follow-up and poor contact with the connecting portion, resulting in imperfect sealing and intrusion of water and the like. c; The connecting portion is derailed or disconnected in the container in order to inject and solidify the heat-meltable resin while the connecting portion is inserted into the container. Since the conductor must be passed through the tube, it takes time and effort, and a gap is easily formed. Further, after both ends of the conductor are connected to other members, the conductor cannot be passed through the tube, so that coating cannot be performed. In addition, since none of the above-mentioned covering materials can be completely waterproofed, in order to prevent adverse effects such as poor connection or disconnection due to water intrusion or salt damage, for example, the harness is routed to the interior of the vehicle to connect the connecting portion. Although it is designed to be put in the cabin, it takes time and effort to wire the harness, and the length of the harness becomes longer and heavier, and it is necessary to secure a wider space for the harness. Become. (Means for Solving the Problems) In order to solve the above problems, a first invention is to provide a crosslinkable hot melt containing a copolymer of acrylate ester, styrene butadiene rubber and tolylene diisocyanate on a heat-shrinkable sheet. A layer is formed to form a covering material for the conductive connecting portion. In the second invention, the heat-shrinkable sheet is coated on the outside with the above-mentioned covering material, and a copolymer of acrylate ester, styrene-butadiene rubber, and tolylene diisocyanate is provided. After covering the connecting portion of the conductor with the crosslinkable hot melt layer contained inside, the coating material is heated and adhered to cover the connecting portion of the conductor. (Operation) Since the covering material has a heat-shrinkable sheet, the heat-shrinkable sheet is placed outside and the conductor connecting portion is wrapped and thermocompression-bonded. Completely conforms to the surface shape of In addition, the crosslinked hot melt layer containing the copolymer of acrylate ester and styrene-butadiene rubber and tolylene diisocyanate is thermally fused to the heat-shrinkable sheet, so that the molten resin adheres to the joint and the surrounding coating. As a result, it is integrated with the coating material, and the sealing coating function is improved. Further, by forming the covering material in a seal shape, the conductor connecting portion can be easily covered with a simple tool, and the conductor connecting portion can be covered even after the wire harness is assembled. Workability is improved. (Example) Hereinafter, an example of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing a covering material of a conductor connecting portion according to the present invention. The coating material 1 is formed by forming a crosslinkable hot melt layer 3 on a heat-shrinkable sheet 2. The crosslinkable hot melt contains a copolymer of an acrylate ester and a styrene-butadiene rubber and tolylene diisocyanate. The heat-shrinkable sheet 2 has a property of shrinking when heated. Examples of the shrinkable film usable as the heat-shrinkable sheet 2 include a silicone-based shrinkable film (manufactured by Shin-Etsu Chemical Co., Ltd.) and a polyester-based shrinkable film. (Mitsubishi Resin, Teijin Chemicals), vinyl chloride shrink film (Mitsubishi Resin), polyolefin shrink film (Mitsubishi Resin), fluorine shrink film (Daikin Industries), and the like. The adhesive used as the crosslinkable hot melt layer 3 preferably has a heating condition of 120 ° C to 200 ° C. Next, a method for manufacturing the coating material 1 will be described.
As shown in FIG. 2, a crosslinkable hot melt solution 6 obtained by diluting a crosslinkable hot melt resin with a solvent is placed in a container 5. A roller 7 made of polypropylene resin, polyacetal resin, fluorine resin or the like is provided in the container 5, and a coater 8 is further provided on the roller 7. Then, the shrink film 9 is conveyed while being sandwiched between the roller 7 and the coater 8, and the crosslinkable hot melt solution 6 is adhered to the surface of the shrink film 9.
The solvent constituting the crosslinkable hot melt solution 6 is volatilized by 10 or the like to form a strip-shaped coating material sheet 11, and the strip-shaped coating material sheet 11 is wound by a roller 12 or the like. At the time of use, the covering material sheet 11 is cut into a shape corresponding to the length and diameter of the connecting portion to obtain the sheet-like covering material 1. When the connecting portion of the conductor is covered with the covering material 1, after connecting the lead wire as the conductor, the conductor is formed into an appropriate shape as described above, for example, as shown in FIG. One cut piece of the covering material 1 is bent, and the heat-shrinkable sheet 2 is placed outside with the crosslinkable hot melt layer 3 inside, and the connecting portion 15 of the conductor such as a lead wire is wrapped. The part is pulled in the direction of arrow A and is heated by a heater (not shown) from the outer side of the covering material 1 in a state of following the outer peripheral surface of the connecting part 15 so as to be in close contact with the covering material 1 at the same time or after heating using a press or the like. Both ends of the covering material 1 are thermocompression-bonded, and the connecting portion 15 of the conductor is covered with the covering material 1 as shown in FIG.
In this case, the above-mentioned heating and pressing can be simultaneously performed by using a heat press. For example, as shown in FIG. 4 (a), two coating materials 1 are used, and one coating material 1 is thermally contracted from the upper side and the other one from the lower side. After wrapping the conductive sheet 2 outside with the crosslinkable hot melt layer 3 inside so as to sandwich the connecting portion 15 of a conductor such as a lead wire, the sheet is heated by a heater, and each coating material 1 is pressed using a press or the like. Both ends may be thermocompression-bonded, and the connecting portion 15 of the conductor may be covered with the covering material 1 as shown in FIG. In addition to the above-described method, the bonding of the coating material 1 may be performed by, for example, bonding by ultrasonic heating, bonding by high-frequency dielectric heating, bonding by microwave heating, or bonding of the coating material 1 instead of pressing by pressing or the like. Bonding can also be performed using a fixture that fixes the parts together. Here, specific experimental results will be described. First, as an experimental sample, a coating material in which an acrylic hot melt composition was applied to a thickness of 0.5 mm and coated on the following polyester shrink film was used. Polyester shrink film Product name: Himiuchibu PET (Mitsubishi Resin, trade name) Main component: Polyethylene terephthalate Thickness: 0.06 mm Thermal characteristics: Melting point: 255 ° C Operating temperature: -60 to 150 ° C Continuous operating temperature: 125 ° C Shrinkage: 50% in the radial direction, 25% in the length direction Acrylic hot melt composition Grade: AR-810 (Kurashiki Boseki Co., Ltd.) Ingredients: 100 parts by weight of copolymer of acrylic acid ester and styrene butadiene rubber and TDI as catalyst (Tolylene diisocyanate) Cross-linked hot melt containing 2.5 parts by weight, phenol-modified petroleum resin such as coumarone indene resin as other tackifier resin, diluent solvent (toluene,
Organic solvent such as ethyl acetate) in the weight of the above copolymer.
A heat-shrinkable sheet laminated with the above-mentioned crosslinkable hot melt agent containing 60% by weight is covered in a hatch shape so that the electric wires are overlapped on the joints of the 3D diameter vinyl chloride-coated Cu electric wires at the joints. After the both ends of the sheet were pressed and thermocompressed under heating conditions of 140 ° C. for 10 sec, the following test was performed. Test 121 ° C, pressure 2
The sample was immersed for 30 hours under the test conditions under steam at atmospheric pressure. Test Results As a result of the above test, it was confirmed that there was no oxidation corrosion due to vapor permeation in the Cu electric wire at the connection portion. The coating material and the coating method according to the present invention are implemented in, for example, a connection portion of a wire harness for an automobile, a connection portion with a control panel of electric equipment, a connection portion of a power line or a communication line, a cable connection portion of a plant, and the like. be able to. (Effect of the Invention) As described above, by using the covering material according to the present invention for covering the connecting portion of a conductor such as an electric wire, the covering material closely follows the outer shape of the connecting portion, and adheres to the outer shape. As a result, the connecting portion can be completely protected by water. In addition, since the number of conductors and the like are reduced, the weight can be reduced and the space can be effectively used. In addition, the insulation, strength and weather resistance of the coating material are improved. Further, the coating operation is simplified, the time is shortened, and the automation in the line can be achieved, thereby improving the productivity.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a covering material of a conductor connecting portion embodying the present invention, FIG. 2 is a schematic diagram showing an example of a method of manufacturing the covering material, FIG. FIG. 4 is an explanatory view showing a different example of a method of coating the conductor connecting portion with the coating material. DESCRIPTION OF SYMBOLS 1 ... Coating material, 2 ... Heat-shrinkable sheet 3 ... Crosslinkable hot melt layer, 15 ... Conductor connection part

Claims (1)

(57) [Claims] In a coating material for covering a connecting portion of the conductor, a crosslinkable hot melt layer containing a copolymer of acrylate ester and styrene-butadiene rubber and tolylene diisocyanate is formed on a heat-shrinkable sheet. Covering material of the conductive connecting part. 2. In a coating method for coating a connecting portion of a conductor, a coating material formed by forming a crosslinkable hot melt layer containing a copolymer of acrylate ester and styrene-butadiene rubber and tolylene diisocyanate on a heat-shrinkable sheet. Wrapping a conductor connecting portion with a heat-shrinkable sheet of the covering material on the outside and a crosslinkable hot melt layer on the inside, and then heating and bonding the covering material, the method for coating a conductor connecting portion. .