WO2005071792A1

WO2005071792A1 - Method for waterproofing connection part of covered wire

Info

Publication number: WO2005071792A1
Application number: PCT/JP2005/001091
Authority: WO
Inventors: Shin Takahashi; Yoshiharu Oohashi; Kenji Iwasaki
Original assignee: Yazaki Corporation; Toagosei Co., Ltd.
Priority date: 2004-01-27
Filing date: 2005-01-27
Publication date: 2005-08-04
Also published as: JPWO2005071792A1; CN1914771A

Abstract

Disclosed is a method for waterproofing connection parts of covered wires which enables to surely make an electrically connected connection part of a covered wire waterproof by a simple and quick process at low cost. Specifically disclosed is a method for waterproofing connection parts of covered wires wherein a curing sealing material (65) is injected into a protective cap (60) for protecting a connection part (75) of a covered wire (71), then the connection part (75) and a covered portion (71a) near the connection part of the covered wire (71) are put in the sealing material (65), and then the sealing material (65) is cured. The sealing material (65) is a photocuring cyanoacrylate resin composition which has a viscosity of not more than 200 mPa·s at 25˚C in the uncured state and a tensile elongation at break of not less than 20% after curing. The sealing material is cured by irradiation of an electromagnetic wave having a wavelength capable of curing the sealing material.

Description

Specification

Waterproof treatment method for insulated wire connection

Technical field

The present invention relates to a method of waterproofing a connection portion of a covered electric wire, and particularly to a method of waterproofing a connection portion of a covered electric wire suitable for an automobile wire harness.

Background art

[0002] A wire harness routed around an automobile body is provided with a large number of wire connection portions in which coated wires are branched and connected to each other. It must be reliably insulated from the outside and waterproof. Therefore, various electric wire connection methods have been conventionally proposed.

[0003] For example, according to the electric wire interconnection device disclosed in Japanese Utility Model Application Laid-Open No. 63-157163, as shown in Fig. 4, the core portions of the electric wires A2 and A3 of the wire harness A1 are connected to each other to connect the electric wires. After forming A4, the connecting portion A4 is wrapped so that a pair of insulating sheets A5 of the same material as the covering of the wires A2 and A3 are overlapped, and then the insulating sheet A5 is adhered by ultrasonic fusion. Coating. However, in the case of the connecting device between the electric wires, water may enter the insulating sheet A5 from a gap between the electric wire and the sheet or a gap between the electric wires. The A4 cannot be waterproofed reliably. In addition, since an ultrasonic welding machine is required, there is a problem that the cost of manufacturing equipment increases.

[0004] Further, according to the method for connecting a covered electric wire disclosed in Japanese Patent Application Laid-Open No. Hei 11-189881, as shown in FIG. 5 (a), the cores of a pair of electric wires B6 are twisted together to form a connecting portion B7. After the formation, the spacer B8 is inserted between the pair of electric wires B6. Next, the electric wire B6 is inserted into the large-diameter portion B9a of the heat-shrinkable tube B9, and the connection portion B7 is inserted into the small-diameter portion B9b holding the metal sleeve B10. Then, as shown in FIG. 5 (b), when the assembly is completed, the metal sleeve B10 is urged to firmly fix the connection portion B7, and then the heat-shrinkable tube B9 is shrunk by heating. It is sealed by closely contacting the surface of the electric wire B6. However, this method of connecting insulated wires uses heat shrink tubing, metal sleeves, spacers, For example, many materials are required, and the cost is high. In addition, if the number of work processes is large, manufacturing equipment is required for each process that can be performed by force, so the manufacturing cost increases due to equipment costs. Furthermore, since the tip having a large contact resistance between the coating and the inner surface of the tube hits the end of the metal sleeve B10, it is not easy to insert the connection portion B7 into the metal sleeve B10.

[0005] Further, in the techniques disclosed in Japanese Utility Model Application Laid-Open No. 63-157163 and Japanese Patent Application Laid-Open No. 1-189881, once water enters the core, once the water enters the core, a further capillary action causes the gap between the cores. Water penetrates into the coating through gaps and leaks the current flowing through the wires.

[0006] According to the method of connecting a covered electric wire disclosed in Japanese Patent Application Laid-Open No. 9-55278, as shown in FIG. After the connection, the connection part 25, the core wire 21b, and the coating 21a near the core wire 21b are immersed in a cyano-based adhesive to allow the cyano-based adhesive to penetrate into the gap between the core wires, and then the connection part 2 5 and the core wire 2 lb, and the covering 21a near the core wire 2 lb are covered with an insulating member to be hermetically sealed. In the case of the method for connecting the covered electric wires, the Cyanide adhesive is penetrated into the gaps between the core wires and solidified to thereby prevent water from entering the sheath between the core wires. There is a problem that the cured product of the cyano-based adhesive that covers the surface is too thin to be easily hydrolyzed by moisture.

[0007] Further, according to the method of sealing a wire connection portion disclosed in Japanese Patent Application Laid-Open No. H11-178142, as shown in FIG. 7, conductor ends of a plurality of wires W are connected to each other and formed. The outside of the electric wire connection portion 81 is covered with a heat-shrinkable tube 83 that is coated with a hot-melt adhesive 83 on the inner wall and sealed with a one-sided S-hot-melt adhesive 83, and the heat-shrinkable tube 82 Is heat-treated to make them adhere to each other. In this method of sealing the wire connection part, the gap is filled with a hot-melt adhesive that has melted the wire connection part and solidified. Therefore, the wire connection part is sealed, but it can be said that the wire connection part is in a molten state. Since the adhesive has low fluidity, it is difficult to fill the gap between the wires. .

Patent Document 1: Japanese Utility Model Publication No. 63-157163

Patent Document 2: Japanese Patent Application Laid-Open No. 01-189881 Patent Document 3: Japanese Patent Application Laid-Open No. 09-055278

Patent document 4: JP-A-11-178142

Disclosure of the invention

Problems to be solved by the invention

[0008] The present invention solves the above-mentioned conventional problems, that is, a simple, quick, low-cost, and reliable waterproofing treatment can be applied to a connection portion of an electrically connected coated electric wire. An object of the present invention is to provide a method of waterproofing a connection portion of an electric wire.

Means for solving the problem

[0009] The method for waterproofing a joint of a covered electric wire according to the present invention has been made to solve the above-mentioned problem, and after injecting a curable sealing material into a protective cap for protecting a joint of a covered electric wire, In the method for waterproofing a connection portion of a covered electric wire, in which a connection portion of the covered electric wire and a covered portion near the connection portion of the covered electric wire are inserted into a sealing material, and the curable sealing material is cured, the curable seal is provided. A photocurable cyanoacrylate resin composition having a viscosity of 200 mPa's or less at 25 ° C in an uncured state and a tensile elongation at break of 20% or more after curing, The curing treatment is performed by irradiating the curable sealing material with an electromagnetic wave having a wavelength capable of curing the curable sealing material.

[0010] Further, in the method for waterproofing a connection portion of a coated electric wire according to the present invention, the method for waterproofing a connection portion of a coated electric wire according to the present invention, wherein the photocurable cyanoacrylate resin composition comprises the following (A), (A) The cured product of the photocurable cyanoacrylate resin composition containing B) and (C) has a tensile elongation at break of 20% or more.

(A) 2-cyanoacrylate

(B) a photopolymerizable resin component having at least two of atariloyl and methacryloyl groups in the molecule

(C) Photo-radical polymerization initiator

[0011] Further, in the method for waterproofing a connection portion of a covered electric wire according to the present invention, the protective cap is made of a material that can transmit the electromagnetic wave, in accordance with the above-described method for waterproofing a connection portion of a covered electric wire. Transmitting the electromagnetic wave of the above wavelength from outside the protective cap to the protective cap. Irradiate the curable sealing material.

Effect of Invention 〇

[0012] According to the method for waterproofing a joint of a covered electric wire of the present invention, the connection of the electrically connected covered electric wire is simple, quick, excellent in productivity, low in cost, excellent in cost performance, and Reliable waterproof treatment can be performed.

Brief Description of Drawings

FIG. 1 is a view showing a connection portion of an electric wire terminal processed by the method of the present invention.

FIG. 2 is a perspective view showing an electric wire assembly.

FIG. 3 is a view showing a state in which an electric wire assembly is inserted into an insulating cap containing an adhesive.

FIG. 4 is a diagram showing a method for connecting electric wires disclosed in Japanese Utility Model Laid-Open No. 63-157163.

FIG. 5 is a view showing a method for connecting a covered electric wire disclosed in Japanese Patent Application Laid-Open No. 11-189881.

FIG. 6 is a view showing a method of connecting a covered electric wire disclosed in Japanese Patent Application Laid-Open No. 9-55278.

FIG. 7 is a view showing a method of connecting a covered electric wire disclosed in Japanese Patent Application Laid-Open No. 11-178142.

Protective cap

61 Large diameter protection cap

62 Protection cap small diameter part

70 Wire assembly

71 Wire (Coated wire)

71a Coated part

71b Qi, line

75 Connection

65 Curable sealing material

200 Wire terminal connection processing section

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] In the present invention, the curable sealing material is a photo-curable cyanoacrylate-based material. It is necessary to use a resin composition. In other words, by using a curable sealing material having photocurability, curing can be performed quickly, reliably and at low cost, and the curable sealing material is a cyanoacrylate resin composition. Because of this, after curing, it becomes a three-dimensionally crosslinked water-resistant wall that is difficult to hydrolyze (the first water-proof wall).

[0016] Furthermore, a trace amount of water present on the surface of the coated electric wire or the surface of the connection portion functions as an initiator, and the surrounding cyanoacrylate-based resin composition undergoes anion polymerization to form an anion which becomes a second water stop wall. Since the cured polymer resin layer is formed, even if a small amount of water breaks through the first water blocking wall and enters the vicinity of the core wire, the second water blocking wall completely prevents water from entering the gap between the core wires. Can be prevented.

[0017] In the present invention, the photocurable resin composition is a chemically reactive resin composition capable of undergoing radial polymerization by irradiation with light.

The photo-curable cyanoacrylate resin composition used in the present invention must have a cured product having a tensile elongation at break of 20% or more. Tensile rupture elongation of the cured product was measured using a dumbbell No. 3 test piece manufactured in accordance with JIS K6251 under the conditions of 23 ° C and 50% relative humidity (RH) at a tensile speed of 10 mm / min. It is a value measured using a machine

[0019] Generally, a cured product of a cyanoacrylate resin composition is hard and brittle, and the cured product has a tensile elongation at break of less than 5%. When a thermal shock is applied to a cured product of such a widely used cyanoacrylate resin composition, cracks occur. Therefore, when such a widely used cyanoacrylate resin composition is used, there is a possibility that sufficient waterproof performance may not be maintained, but in the present invention, the tensile elongation at break after curing is 20% or more. Since the photo-curable cyanoacrylate resin composition is used, the thermal shock resistance is dramatically improved, so that such cracking is prevented, and as a result, the electric wire The connection portion can be reliably waterproofed. Specifically, it can satisfy the required heat resistance, cold resistance, heat and humidity resistance, cold and thermal shock resistance, water resistance and salt water resistance required for automobile wire harnesses, and has a highly reliable waterproofing treatment. Can be.

[0020] Such a photocurable cyanoacrylate-based resin composition having a tensile elongation at break of 20% or more after curing can be added to a normal cyanoacrylate-based resin composition, for example, by adding a molecule in the molecule. This can be achieved by blending a photopolymerizable resin component having at least one of a acryloyl group and a methacryloyl group.

Here, the photocurable cyanoacrylate resin composition used in the present invention preferably contains the following (B) in addition to the following (A) and (C).

(A) 2-cyanoacrylate

(C) Photo-radical polymerization initiator

Here, these components will be described in more detail.

(A) 2-Cyanoacrylate is a monomer having anionic polymerizability and radical polymerizability, and is a main component of a photocurable cyanoacrylate-based resin composition. As such a 2-cyanoacrylate, those widely used as a main component of a cyanoacrylate-based instant adhesive can be applied. Preferred 2-cyanoacrylates are compounds represented by Formula I below.

[0023] [Formula 1] Formula I

CN

H ₂ C = C

COOR

(In the above formula, R is an alkyl group, a cycloalkyl group, a haloalkyl group, an alkoxyanol group, an alkenyl group, a cycloalkenyl group, an alkynyl group or an aryl group.)

[0024] Preferably, the 2-cyanoacrylate is an alkyl, cycloalkyl, haloalkyl, alkoxyalkyl, alkenyl, cycloalkenyl, cycloalkenyl, alkynyl, And R is an alkyl group such as methyl 2-cyanoacrylate, ethyl 2-cyanoacrylate, n-propyl 2_ cyanoacrylate, i-propyl 2-cyanoacrylate, n Alkyl 2-cyanoacrylates such as _butyl 2-cyanoacrylate, i_butyl 2-cyanoacrylate, and n-octyl 2-cyanoacrylate; aryl 2-cyanoacrylate wherein R is an unsaturated group; Propagill 2-si Alkenyl or alkynyl 2-cyanoacrylates, such as anoacrylate; 2,2,2-trifluoroethyl 2-cyanoacrylate; 2,2,3,3-tetrafluoropropyl 2-fluoroalkyl, such as 2-anoarylate Forces include alkoxyalkyl 2-cyanoacrylates such as 2-cyanoacrylates, methoxyethyl 2-cyanoacrylate, ethoxyxyl 2-cyanoacrylate, and the like, but are not limited thereto. These 2-cyanoacrylates may be used alone or in combination of several kinds.

[0025] More preferred 2-cyanoacrylates used in the present invention include ethyl 2-cyanoacrylate, n_propyl 2-cyanoacrylate, i_propyl2-cyanoacrylate, and n_butyl 2-cyanoacrylate. I-butyl 2-cyanoacrylate, methoxyethyl 2-cyanoacrylate, and ethoxyxetinole 2-cyanoacrylate.

[0026] The (B) photopolymerizable resin component having at least two of atariloyl group and methacryloyl group in the molecule used in the present invention is a photocurable cyanoacrylate resin composition. What is necessary is just to be able to give elongation to hardened | cured material. Specific examples include the following.

[0027] Polyethylene glycol di (meth) acrylate (commercially available products include ARONIX M-260: manufactured by Toagosei Co., Ltd., NK ester A-600, 23G: manufactured by Shin-Nakamura Chemical Co., Ltd., and so on) , Polypropylene glycol di (meth) acrylate (Alonics M-270: manufactured by Toagosei Co., Ltd., NK ester APG-700: manufactured by Shin-Nakamura Chemical Co., Ltd.), urethane (meth) acrylate (Alonics M-1310: Toa) Synthetic Co., Ltd., UV3000B: Nippon Synthetic Chemical Industry Co., Ltd.), Polyester (meta) acrylate (Aronix M-6100: Toagosei Co., Ltd., KAYARAD HX-620: Nippon Kayaku Co., Ltd.), Bisphenol Examples of A include E-modified di (meth) acrylate (Alonics M-210: manufactured by Toagosei Co., Ltd.), but are not limited thereto. These photocurable resins may be used alone or as a mixture of several types. It should be noted that the above “(meta) atrialate” indicates that it may be “metaarylate” or “atarilate” (hereinafter the same).

[0028] Among these photocurable resins, polyethylene glycol di (meth) atalylate, polypropylene glycol di (meth) atalylate, urethane (meth) atalylate, polyester (meth) It is preferred to use atalylate.

Further, in order to make the cured product of the curable sealing material excellent in resistance to cold and thermal shock, the glass transition point (Tg) of the cured photocurable resin is preferably 0 ° C. or less. . Although the lower limit is not particularly limited, it is practical to be _50 ° C or more in consideration of adhesiveness.

[0030] The amount of the photocurable resin to be added to 2-cyanoacrylate is more preferably 1% by weight or more and 50% by weight or less based on the total amount of both. Is from 10% by weight to 40% by weight. If the amount of the photocurable resin component is less than 1% by weight, it may not be possible to impart sufficient elongation to the cured product after curing, while if it exceeds 50% by weight, the viscosity of the resin composition may increase and the core wire may be hardened. There are problems such as that the resin composition may not penetrate into gaps such as spaces, and that instantaneous adhesiveness is slow.

The (C) radical photopolymerization initiator used in the present invention has (A) 2-cyanoacrylate and (B) at least one of atariloyl group and methacryloyl group by hydrogen abstraction or cleavage by light irradiation. Known ones that initiate the radical polymerization of the photopolymerizable resin component can be used. Specific examples include the following.

(1) Examples of the hydrogen abstraction type include benzophenones such as benzophenone, 2,4-dichlorobenzenebenzophenone, benzophenone such as methyl 0-benzoylbenzoate, benzyl such as benzyl and 4,4′-dimethoxybenzyl, and camphor. There are ketones such as quinone.

(2) Examples of the photocleavable type include benzoin-based compounds such as benzoin, benzoin methyl ether and benzoin ethylene ether, and acetophenone-based compounds such as acetophenone, 4-phenoxydichloroacetophenone, and 4_t-butynoledichloroacetophenone. 2-hydroxyketones, such as 2-hydroxy-2-methynoleic 1-phenylenolone, 1-hydroxy-cyclohexylenolene ketone, methyl isobutylyl methyl phosphinate, methyl isobutyrolene methyl phosphinate 2,4,6_trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6_trimethylbenzoyl) -phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2 , 4, 4_ trimethylpentyl phosphine oxide Les, a force limited to those with shea Le phosphine oxide and the like. These photo-radical polymerization initiators may be used alone or in combination of several kinds.

[0034] Among these photo-radical polymerization initiators, high hydroxy ketones and acyl phosph An oxide system is preferred from the viewpoint of photocurability. These photoradical polymerization initiators are (A

) 0.01% by weight or more and 10% by weight or less, preferably 0.1% by weight, based on the total amount of 2-cyanoacrylate and (B) the photopolymerizable resin component having two (meth) atalyloyl groups in the molecule. Not less than 5% by weight.

[0035] 〇Other components

In the photocurable cyanoacrylate resin composition used in the present invention, the following stabilizers, polymerization accelerators, polymerization initiators, thickeners and other additives are usually used as desired components. It may be appropriately compounded within a certain range.

[Stabilizer] A stabilizer for improving the storage stability of the curable sealant, such as sulfur dioxide, nitric oxide, hydrogen fluoride, sultone compound, BF complex, methanesulfonic acid, p_toluenesulfonic acid, etc. And radical polymerization stabilizers such as hydroquinone, hydroquinone monomethyl ether, catechol and pyrogallol.

[Polymerization accelerator] [0037] The polymerization accelerator is used to enhance the anion polymerization of the curable sealing material to increase the bonding speed, and examples thereof include crown ethers, silacrown ethers, and caritas allenes.

[Polymerization initiator] [Polymerization initiator] This is for increasing the radical polymerizability of the curable sealing material, and organic peroxides such as di-t-butyl phenol peroxide and cumene hydride peroxide are added.

[Thickener] The photo-curable cyanoacrylate resin composition of the present invention has a viscosity at 25 ° C. of 200 mPa's or less, and controls the permeability to electric wires within this range. For this purpose, a thickener can be used, and examples thereof include polymethyl methacrylate, methyl methacrylate / (meth) atalylate copolymer, and cellulose derivatives.

[0040] In addition to the above, an adhesiveness-imparting agent, a dye, a fragrance, a filler, a cross-linking agent, one of taffna, and the like are added according to the purpose. As for these, all conventionally known techniques can be used.

[0041] The photocurable cyanoacrylate resin composition used in the present invention must have a viscosity at 25 ° C of 200 mPa's or less as measured by an E-type viscometer. OOmPa's or less. When the viscosity of the curable sealing material is higher than 200 mPa's, the penetration of the curable sealing material into the gap between the core wires due to the capillary phenomenon becomes insufficient, and The thickness of the anion polymer resin layer in the coating which is the water blocking wall becomes thin or almost disappears, and a sufficient waterproof effect cannot be exhibited.

[0042] A method for waterproofing a connection portion of a covered electric wire according to the present invention will be described below in detail with reference to the accompanying drawings.

In the connection processing section 200 of the wire end shown in FIG. 1, the core wires 71b exposed from the covering portions 71a of the plurality of covered wires 71 are electrically connected to each other at the force connection portions 75, and A bottomed cylindrical protective cap made of an insulating synthetic resin that penetrates the connecting portion 75 and the connecting portion 75 of the covered electric wire 71 near the connecting portion 75 and that is made of an insulating synthetic resin that transmits electromagnetic waves of 200 OO nm to protect the connecting portion of the covered electric wire. Covered by 60. A curable sealing material (a photo-curable cyanoacrylate-based resin composition) 65 filled between the protective cap 60, the core wire 7 lb, and the covering portion 71a near the core wire 7 lb forming the connection portion 75. Radical polymerizes by light irradiation to form a thick and strong layer.

[Connection method of electric wire]

A description will be given of a method of connecting wires in such a wire terminal connection processing unit 200. First, after removing the covering portions 71a of the ends of the plurality of electric wires 71 and exposing the respective core wires 71b, the electric wires 71 are moved along each other so that the ends are almost aligned. Then, by welding or crimping the core wires 71b of the respective wires 71 in a state where they are in close contact with each other, a connection portion 75 where the core wires 71b are electrically connected to each other is formed, and a wire assembly 70 as shown in FIG. To manufacture.

[Method of Dipping into Curable Sealing Material, Method of Sealing between Core Wires and Sealing Between Electric Wires]

Next, as shown in FIG. 3, the end portion of the wire assembly 70 is inserted into the curable sealing material 65 in the bottomed cylindrical protective cap 60 in which the curable sealing material 65 has been previously injected. Then, not only the connecting portion 75 and the core wire 71b but also the covering portion 71a near the core wire 71b is immersed in the curable sealing material 65. Here, the covering portion 71a in the vicinity of the core wire 71b usually means a covering portion of 3 mm or more and 20 mm or less. If the covering portion is too short, the reliability of waterproofing may be reduced. If the covering portion is too long, the processing portion becomes too large. For example, in the case of a wire harness, handleability deteriorates and material waste increases. Since the layer of the curable sealing material 65 does not cure for a short time due to the relatively thick anion polymerization, the wire assembly Insertion of the terminal part of the body 70 is easy, and the use of a curable sealing material 65 with a viscosity of 2 OOmPa's or less at 25 ° C in the uncured state allows penetration into the gap between the core wires due to capillary action. At a high speed, the end portion of the wire assembly 70 is inserted, and a few seconds later, the curable sealing material 65 sufficiently penetrates into the gap between the core wires. The portion of the penetrating curable sealing material 65 that comes into contact with the surface of the core wire is anion-polymerized by using the water present on the surface of the core wire as an initiator and adheres tightly to the core wire to function as a waterproof sealing material (seal layer). In addition, the protective cap 60 penetrates and wraps around the wires, and the curable sealing material 65 where light from outside does not come into contact is also cured by anionic polymerization using the moisture present on the surface of the covered portion 71a as an initiator to cure the wires. Functions as a waterproof sealing material (seal layer) between them.

[Photocuring Method and Sealing Method of Curable Sealing Material]

The uncured portion of the curable sealing material 65 filled between the terminal insertion portion of the wire assembly 70 and the protective cap 60 is an electromagnetic wave having a wavelength capable of curing the curable sealing material from the outside of the protective cap. For example, radical polymerization can be easily performed by irradiating, for example, visible light or ultraviolet light or both, and light can be applied to the connection portion 75, the core wire 71b, and the covering portion 71a near the core wire 71b (connection portion 75). The ability to achieve light curing of essential parts in a short time.

[0047] [Electromagnetic wave irradiation source and amount required for curing]

The source of electromagnetic wave irradiation used in the present invention includes a low-pressure mercury lamp, a high-pressure mercury lamp, a xenon lamp, a metalno, a ride lamp and the like. Electromagnetic waves are required to be of a wavelength that can cure the curable sealant used. UV and visible light, typically 200-500 nm. The amount of light transmitted through the protective cap 60 required for photocuring of the curable sealing material cannot be limited because it is affected by the type and amount of photopolymerization initiator mixed in the curable sealing material. 100 mj / cm ² or more, preferably especially 200 mj / cm ² or more 10000 mJ / cm ² hereinafter.

[0048] [Protective cap]

The material of the protective cap may be any material as long as it is insulative and transmits electromagnetic waves of a wavelength that can cure the curable sealing material to be used, typically an electromagnetic wave of 200 nm or more and 500 nm or less. Bull resin, polypropylene, polyethylene, silicone, Resin such as krill, polycarbonate, polyester, polyamide, polytetrafluoroethylene and the like.

[0049] The shape of the protective cap is not limited as long as it can protect the connection portion of the covered electric wire from electrical, mechanical or chemical impact. For example, there are a bottomed cylindrical shape, a cone shape, a square shape, and the like. The shape of the opening and the concave portion may be any shape so that the connection portion of the covered electric wire can be easily inserted.

[0050] When the electromagnetic wave is supplied to the curable sealing material by another method, instead of transmitting the electromagnetic wave through the protective cap, for example, the optical fiber is connected to the connection portion of the coated electric wire with the curable sealing material. If the optical fiber is used as a light guide and electromagnetic waves are supplied to the curable sealing material, the protective cap should be made of a material that cannot transmit electromagnetic waves of a wavelength that can cure the curable sealing material. it can. In this case, the optical fiber may be cut at an appropriate place after the curable sealing material is cured.

[0051] As described above, in the present invention, the connection-treated portion of the covered electric wire was inserted and immersed in the protective cap containing the low viscosity, relatively extensible photocurable cyanoacrylate resin composition. After that, it is simple to irradiate electromagnetic waves, and it is possible to apply extremely simple, quick, low-cost, and reliable waterproofing to the connection portion of the electrically connected insulated wire. Example

Hereinafter, the present invention will be described more specifically with reference to examples. The performance evaluation in each example and comparative example was performed according to the following method.

Made of flexible chloride resin, thickness: 1mm

Wire Assembly>

Wire assembly formed by crimping a core wire at one end of 10 covered wires [0053] <Photo-curable cyanoacrylate resin composition>

Curable sealing materials having the compositions shown in Tables 1 and 2 were prepared, and their properties were evaluated as described below. For comparison, a similar study was also conducted on curable sealing materials having the compositions shown in Table 3.

[Viscosity] The viscosity at 25 ° C was measured using an E-type viscometer. [Set Time] In accordance with JIS K 6861, a time required to reach a predetermined adhesive strength using a copper test piece was defined as a set time.

[Photocurability] Using a conveyor-type light irradiator (Metal halide lamp 1500W) manufactured by Eye Graphics Co., Ltd., the integrated amount of light required to cure a thickness of 2 mm was measured. The measurement of the light amount was performed using a photodetector UVD-C365 having a central light reception at a wavelength of 365 nm and UIT-150 manufactured by Shio Electric Co., Ltd.

[Tensile rupture elongation] Tensile rupture elongation f of the cured product: A dumbbell No. 3 type test piece (thickness: 2 mm) manufactured in accordance with IS K6251 was subjected to a tensile test at 23 ° C and 50% RH. Speed: Measured using a tensile tester under the condition of 10 mmZmin.

[Suction of curable sealing material, raising height] A curable sealing material lg is poured into a protective cap with a dropper, and an electric wire assembly is inserted therein, and an eye graphics light irradiator (high pressure mercury lamp) is used. Using 600 W), light irradiation (integrated light amount: 6000 mj / cm ² ) was performed from both sides of the protective cap. The insulator portion of the waterproofed wire was cut open 24 hours later, and the suction and lifting height of the curable scenery material were measured.

[Cooling and Heat Shock Resistance] A cold and heat shock test was conducted on the waterproofed wire in the same manner as described above, and the number of cycles until cracks occurred in the curable sealing material was measured.

Test conditions: Temperature conditions: 100 ° C, 60 minutes. Cold conditions: -40 ° C, 60 minutes

[0060] The abbreviations in Table 1 indicate the following compounds (however, Tg in parentheses indicates the glass transition temperature of a cured product of the compound).

[0061] M-1310: polyol urethane diatalylate (Tg: _25 ° C), HX-620: polyester diatalylate (Tg: _8 ° C), M_225 (Tg: _8 ° C) and M_270 (Tg: _32 ° C) ): Polypropylene glycol diatalylate, M-260: Polyethylene glycol diatalylate (Tg: _34 ° C), M-220: Tripropylene glycol diatalylate (Tg: 90 ° C), DPHA: Dienthaerythritol Penta and hexatalylate (Tg:> 250 ° C).

[0062] Irg819: bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, Irgl80 0: 1-hydroxy-cyclohexylofluene ketone and bis (2,6-dimethoxybenzoyl) -2 75,25 mixture by weight with 4,4,4-trimethylpentylphosphine oxide, D C1173: 2-Hydroxy-1_2_methyl_1_Phenyl-1-propane_1_one, Irgl84: 1-Hydro Example 1 Example 2 Example 3 Example 4 Example 5

Component (A) 2-cyanoacrylate i-butyl (50) i-butyl (70) i-butyl (90) tofutyl (70) tobutyl (70)

(Blend amount (B) Photopolymerizable resin M-1310 (50) M-1310 (30) M-1310 (10) HX- 620 (30) HX- 620 (30)

(wt%)) (C) Photo-radical polymerization initiator Irg819 (3) Irg819 (3) Irg819 (3) Irg8t9 (3) Irg819 (3)

增 Viscous agent PMMA (3)

Evaluation viscosity mPa-s 30 13 10 10 140

Set time seconds 90 10 5 10 20

Light curable mJ / cm ² 4000 4000 6000 4000 4000

Tensile elongation at break% 120 105 35 40 20

Wire suction height mm 15 30 30 30 5

Cold shock resistance Number of cycles> 1000> 1000 600 600 300

Ah ~

Example 6 Example 7 Example 8 Example 9

Ingredient (A) 2-cyanoacrylate i-butyl (70) ί-butyl (70) tobutyl (70) ethoxyxyl (70) (content (B) photopolymerizable resin M-225 (30) Μ-260 (30) M-270 (30) HX-620 (30)

(wt%)) (C) Photo-radical polymerization initiator Irg819 (3) Irg1800 (3) Irg819 (2) Irg819 (2)

增 Viscous agent DC1173 (2) Irg184 (2) Evaluation viscosity mPa 6 10 8 18

Set time seconds 10 20 10 5

Photocurable

4000 4000 6000 6000

Elongation at break% 28 80 78 58

Wire suction height mm 35 30 30 30

Cold shock resistance cycle number 1 loo> 1000> 1000> 1000

SU064

From Table 13 above, the photocurable cyanoacrylate resin composition used in the present invention has a viscosity of 200 mPa's or less and a tensile elongation at break of 20% or more. In all of the cyanoacrylate resin compositions having the above, the set time related to the productivity was 180 seconds or less, so it was determined that good productivity could be secured, and the photocurability was also compared. To ensure good productivity even with low cost equipment It is less than the required 10,000 mj / cm ² , and satisfies the wire suction height of 5 mm or more, which provides sufficient waterproofness. It must have a resistance of at least 100 times, which is necessary for impact resistance.

Further, the connection portion according to the embodiment of the present invention was applied to a wire harness for an automobile, and a test was performed in an environment considered to occur in an actual automobile. It was confirmed that sufficient waterproofness was maintained at the connection portion.

Industrial applicability

According to the present invention, a simple, quick, low-cost, and reliable waterproofing process can be applied to a connection portion of an electrically connected covered wire that can be used for an automobile wire harness or the like. According to the present invention, since the intrusion of water into the insulating member is suppressed, current leakage flowing through the electric wire due to corrosion of the core wire and intrusion of water into the coating does not occur, and the reliability against water resistance and salt water is improved.

Claims

The scope of the claims

[1] After injecting a curable sealing material into a protective cap that protects a connection portion of the covered electric wire, a connection portion of the covered electric wire and a covering portion near the connection portion of the covered electric wire are inserted into the sealing material. Next, in the method of waterproofing the connection portion of the covered electric wire for curing the curable sealing material,

A photocurable cyanoacrylate resin composition having a viscosity of 200 mPa's or less at 25 ° C in an uncured state, and a tensile elongation at break of 20% or more after curing. Yes,

A method of waterproofing a connection portion of a covered electric wire, wherein the curing treatment is performed by irradiating the curable sealing material with an electromagnetic wave having a wavelength capable of curing the curable sealing material.

[2] The photocurable cyanoacrylate-based resin composition contains the following (A), (B) and (C), and is a photocurable cyanoacrylate-based resin composition. The method for waterproofing a joint of a covered electric wire according to claim 1, wherein the cured product has a tensile elongation at break of 20% or more.

(A) 2-cyanoacrylate

(C) Photo-radical polymerization initiator

[3] The protective cap is made of a material capable of transmitting the electromagnetic wave, and the electromagnetic wave having the above wavelength is transmitted through the protective cap from outside the protective cap to irradiate the curable sealing material. 3. The method for waterproofing a connection part of a covered electric wire according to claim 1 or claim 2.