JP5499318B2 - Cable covering mold material and cable terminal using the same - Google Patents

Description

  The present invention relates to a cable covering mold material for molding a cable terminal such as an aviation light cable and a cable terminal using the same.

  Conventionally, rubber has been used as an insulation coating material for an aerial lamp cable, but it has been difficult to reuse rubber because it is used after being crosslinked. Therefore, a reusable cable using a thermoplastic elastomer has been developed as an insulation coating material for an aerial lamp cable.

  The advantage of the thermoplastic elastomer cable is that the material can be reused and the cable end molding process can be simplified.

  The cable connection at the time of this molding process uses a plug / reset connection method in which a rubber-molded plug and a receptacle are combined and connected to the cable end, and a pre-rubber-molded adapter at the actual cable installation site. There is an adapter method in which the end of the cable is opened and a cable connection terminal is attached, and then an adapter is inserted and connected.

  As shown in FIG. 1, the plug and receptacle of the aviation light cable 10 are attached by crimping the pin 11 to the conductor at the end of the cable 10a to be connected, and the socket 12 is crimped to the conductor at the cable end of the other aviation light cable 10b. Then, molding materials 13a and 13b are molded on the outer periphery, and each of them is composed of a cable 10a with a plug 14 and a cable 10b with a recess 15, and the plug 14 and the recess 15 are inserted or fitted together. It connects with. In addition, after the connection, a self-fusing shrinkable tape or an adhesive vinyl tape is wound around the connection portion for insulation reinforcement.

  In this way, the molding process is to cover the surface of the metal fitting connected to the cable terminal, including the cable insulation coating material, in the case of a plug / recep connection method which is one of the cable connections.

  The thermoplastic elastomer cable after the connection can be melt-bonded to the insulation coating material of the cable 10 by using the molding materials 13a and 13b as the thermoplastic elastomer.

  On the other hand, in the rubber cable, since the rubber of the insulating coating material is cross-linked, it cannot be bonded only by covering the rubber used for the molding material. Therefore, although an adhesive is applied, it has been necessary to devise a method such as applying an adhesive after applying a surface treatment (for example, roughening the surface with a polishing machine) to the insulating coating material.

  Thus, the thermoplastic elastomer is excellent in bonding the insulating coating material and the molding material.

JP 2005-54001 A JP 2005-344030 A JP 2002-348343 A

  However, rubber is superior to thermoplastic elastomers for bonding metal fittings and molding materials. This is because, in the adhesion between the rubber and the metal fitting, the adhesive and the rubber are cross-linked and bonded firmly, but the thermoplastic elastomer is not bonded to the adhesive.

  In view of this, the present inventor has developed a resin composition that can provide rubber-like adhesiveness by adding a polyolefin modified with a carboxylic acid for the purpose of bonding a thermoplastic elastomer and an adhesive.

  However, since the carboxylic acid-modified polyolefin adheres well to the metal, adhesion of the resin composition to the device (metal container) becomes a problem when mixing or molding the resin composition, and it must be removed from the device after molding. It turns out that there are new problems that become difficult.

  Accordingly, an object of the present invention is to provide a cable covering mold material that can satisfy the contradictory characteristics, which is not sticking to an apparatus (metal container) at the time of mixing or molding, and exhibits adhesiveness when bonded to metal. The object is to provide a cable terminal using this.

In order to achieve the above object, the invention of claim 1 is a cable used when a cable end having an insulating coating layer made of a polyolefin-based thermoplastic resin is molded to cover the insulating coating layer and the metal surface of the terminal. In the mold material for coating, 1 to 10 parts of polypropylene wax is added to 100 parts by mass of polyolefin-based thermoplastic resin in which polyolefin-based thermoplastic resin modified with carboxylic acid anhydride is mixed at a ratio of 1/10 to 3/10 . A cable covering mold material characterized by containing 10 parts by mass.

  The invention according to claim 2 is the molding material for cable covering according to claim 1, wherein the number average molecular weight of the polypropylene wax is 9000 or less.

  A third aspect of the present invention is the cable terminal according to the first or second aspect, wherein a cable end having an insulating coating layer made of a polyolefin-based thermoplastic resin is molded so as to cover the insulating coating layer and the metal surface of the terminal. It is the cable terminal characterized by carrying out the molding using the cable covering mold material.

  The invention according to claim 4 is the cable terminal according to claim 3, wherein the molding material and the metal surface are bonded using an adhesive when molding.

  According to the present invention, by adding a polypropylene wax to a thermoplastic resin composition containing a carboxylic acid-modified polyolefin that improves adhesion to metal, adhesion during resin mixing or molding can be prevented, and after molding The present invention exhibits an excellent effect that it can provide a molding material for cable covering excellent in adhesion to the metal surface.

It is a figure explaining the plug * rep connection system of an aerial light cable to which the present invention is applied. It is a figure explaining the test method of adhesive evaluation in this invention.

  Hereinafter, a preferred embodiment of the present invention will be described in detail.

  First, as described with reference to FIG. 1, the cable covering mold material of the present invention has good adhesion to the metal on the terminal side, and can also prevent adhesion to the metal during mixing or molding. .

  Hereinafter, the thermoplastic elastomer that is a molding material is expressed as adhesion when it is in a molten state, and is expressed as adhesion when it is in a solid phase.

  The cable coating mold material of the present invention contains 1 to 10 parts by mass of polypropylene wax with respect to 100 parts by mass of a polyolefin-based thermoplastic resin mixed with a polyolefin-based thermoplastic resin modified with a carboxylic acid anhydride. It is not.

  In order to increase the adhesion between the thermoplastic elastomer and the metal, it is necessary to add a carboxylic acid-modified polyolefin to the polyolefin-based thermoplastic resin, but the carboxylic acid adheres to the metal, but sticks to the device (metal container). Therefore, a wax is added to prevent the tackiness at the time of melting of the polyolefin-based thermoplastic resin.

  The carboxylic acid mentioned here refers to maleic anhydride, acetic anhydride, phthalic anhydride, and polyolefin refers to polyethylene, polypropylene, propylene-ethylene copolymer resin, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-acetic acid. Examples thereof include a vinyl copolymer, an ethylene-butene copolymer, an ethylene-methyl methacrylate copolymer, and a styrene-ethylenebutylene-styrene.

  The wax acts as a lubricant at the interface between the device (metal container) and the thermoplastic elastomer and has an action of preventing adhesion.

  As a result of confirming the anti-adhesion effect for various waxes, oleic acid amide was superior for the fatty acid type, and polypropylene wax was superior for the polymer type. However, oleic acid amide is not preferable because it causes adhesion inhibition during adhesion to metal. Polypropylene wax was inferior to oleic acid amide in adhesion to the apparatus (metal container), but there was no problem in work and adhesion to metal was good.

  At this time, the amount of addition of the polypropylene wax was limited to 1 to 10 parts by mass. If the addition amount is less than 1, the adhesiveness is good but the workability is inferior. If the addition amount exceeds 10 parts by mass, the effect on workability is small. This is because the adhesiveness is lowered. The wax functions as a lubricant by bleeding. When the number average molecular weight exceeds 9000, the adhesion is good but the workability is inferior. In addition, since the wax has a molecular weight that is too small and tends to bleed, the appearance and physical properties (melt tension) may be adversely affected. Therefore, the number average molecular weight is preferably 1000 or more.

  In addition, it is preferable from the viewpoint of work that the thermoplastic elastomer and the metal can be directly bonded, but an attempt was made to use an adhesive in order to improve the reliability of the product.

  The adhesive was selected from an epoxy system, an acrylic system, and an olefin system used for bonding a thermoplastic elastomer and a metal. Each adhesive is a two-component adhesive composed of a main component and a curing accelerator, and an optimum adhesive was selected depending on the adhesive strength and ease of handling.

  The olefin-based adhesive showed a slight increase in adhesive strength compared to the case where the adhesive was not applied, and a phenomenon that the adhesive was partially peeled off from the metal together with the insulating coating material was observed. Both epoxy and acrylic adhesives showed increased adhesion, but acrylic adhesives had a fast curing time and showed a variation in adhesion depending on the standing time. Therefore, it is preferable to use the epoxy adhesive in combination with an epoxy adhesive which has a large adhesive force and does not affect the standing time after the adhesive is applied.

  Next, examples of the present invention will be described together with comparative examples.

  Examples 1 to 8 and Comparative Examples 1 to 5 are shown in Table 1.

Each composition in Table 1 is propylene-based elastomer (MFR: 7 g / 10 min, density: 0.87 g / cm ³ ), maleic acid-modified polypropylene (MFR: 1.3 g / 10 min, density: 0.89 g / cm ³ ). , Maleic acid-modified ethylene-ethyl acrylate (MFR: 5 g / 10 min, density: 1 g / cm ³ ), calcium carbonate (average particle size: 1.2 μm, fatty acid surface treatment), flame retardant (non-decapro brominated flame retardant) , Antioxidant (phenolic antioxidant), fatty acid wax (density: 0.90 g / cm ³ , melting point: 119 ° C.), polyethylene wax (density: 0.92 g / cm ³ , number average molecular weight: 2000), polypropylene wax A (density: 0.89 g / cm ^3, number average molecular weight: 3000), polypropylene wax B (density: 0.89 / Cm ^3, number average molecular weight: 9000), polypropylene wax C (density: 0.89 g / cm ^3, number average molecular weight: 15000) was used.

  The compositions shown in Table 1 were mixed while heating with a mixer, the mixture was taken out of the mixer, formed into a sheet with a roll, then pressed with a metal frame to produce a sheet, and the characteristics were evaluated. It was.

  Each characteristic in Table 1 was measured and evaluated by the following procedure.

  (1) The thermoplastic resin composition of the present invention was prepared by mixing at 200 ° C. for 20 minutes using a mixer (200 cc) of Labo Plast Mill (manufactured by Toyo Seiki).

  (2) The extracted mixture was wound around a 6-inch roll maintained at 160 ° C. and stretched to a thickness of 2 mm.

  (3) The workability was taken out of the sample from the roll, and x indicates that the sample was transferred to the roll due to adhesion, and ○ indicates that the sample was not transferred. A sample that is transferred to a roll and can be removed if roll rotation is stopped is indicated by Δ.

  (4) The sample taken out from the roll was press-molded with a metal frame having a thickness of 1 mm and 2 mm at 200 ° C. for 3 minutes to prepare an adhesion evaluation sheet and a tensile test sheet.

  (5) The tensile test measured tensile strength and elongation at a speed of 500 mm / min using a sheet having a thickness of 2 mm in accordance with JIS C-3005.

  (6) A sample for adhesion evaluation was prepared by press-molding a 1 mm sheet on a tin plate at a load of 1 MPa at 200 ° C. for 1 minute. At this time, the thing which applied the epoxy-type adhesive agent to the tinplate, and the thing which does not apply | coat were prepared. The tin plate was selected as the metal because the end fitting used in the plug-and-recep method is tin-plated, and the tin plate is similar in material to a tin-zinc steel plate.

  (7) As shown in FIG. 2, the adhesiveness was peeled at a width of 25 mm and one end in a vertical direction at 50 mm / min with a material sheet (thickness 1 mm) bonded to a metal plate (tinned steel plate; tin plate). The maximum load of the peel force was measured. The maximum load of rubber with good adhesion to the metal fitting was used as a reference for adhesion, and 60 N / 25 mm or more was indicated as ◯, and less than ×.

  In the above, Examples 1-8 satisfy | filled all the target characteristics with a tensile test, workability | operativity, and adhesiveness.

  However, in Example 3, polypropylene wax C having a number average molecular weight of 15000 was used, and although there was no practical problem in roll transfer, polypropylene wax A having a number average molecular weight of 3000 and polypropylene wax having a number average molecular weight of 9000 were used. B is inferior to B. Therefore, it is preferable to use a polypropylene wax having a number average molecular weight of 9000 or less.

  Compared to Examples 1 to 8 above, Comparative Example 1 does not contain maleic acid-modified polypropylene and has no adhesion to metal.

  Comparative Examples 2 and 3 are obtained by changing the polypropylene waxes A to C of Examples 1 to 3 to fatty acid waxes and polyethylene waxes. In Comparative Example 2, the workability is good, but the adhesiveness is obtained without an adhesive. In Comparative Example 3, neither the workability nor the adhesiveness can satisfy the targets.

  Comparative Example 4 is an example in which the addition amount of polypropylene wax A of Example 1 is less than 1, but the adhesiveness is good but the workability target is not satisfied. In Comparative Example 5, the addition amount of polypropylene wax A exceeds 10 parts by mass, and the workability is good, but the adhesiveness to metal is not satisfied without an adhesive.

  From the above, it can be seen that it is preferable to add 1 to 10 parts by mass of polypropylene wax with respect to 100 parts by mass of polypropylene elastomer modified with maleic acid-modified polypropylene.

10 Airlight cable 11 Pin 12 Socket 13a, 13b Mold material 14 Plug 15 Recep

Claims (4)

A cable covering mold material used for molding a cable end having an insulating covering layer made of a polyolefin-based thermoplastic resin so as to cover the insulating covering layer and the metal surface of the end, and modified with a carboxylic acid anhydride. 1 to 10 parts by mass of polypropylene wax is added to 100 parts by mass of polyolefin-based thermoplastic resin in which polyolefin-based thermoplastic resin is mixed in a ratio of 1/10 to 3/10 . Mold material.   The molding material for cable coating according to claim 1, wherein the number average molecular weight of the polypropylene wax is 9000 or less.   A cable terminal for molding a cable having an insulating coating layer made of a polyolefin-based thermoplastic resin, covering the insulating coating layer and the metal surface of the terminal, and molding the cable covering molding material according to claim 1 or 2. A cable terminal characterized by being molded using.   The cable terminal according to claim 3, wherein when molding, the molding material and the metal surface are bonded using an adhesive.

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