CN101887773A - Insulated cable, component for control system, and method for producing component for control system - Google Patents

Abstract

The present invention provides an insulated cable which has a single-core or multi-core insulated wire and a sheath layer formed on the outer periphery of the insulated wire, and which is used for hot-melt adhesion with polyphenylene sulfide resin. The sheath layer is composed of a cross-linked body of a resin composition containing 45% by weight or more of a thermoplastic polyester elastomer. Furthermore, the present invention provides a component for a control system and a method of manufacturing the component for a control system, wherein the component for a control system has the insulated cable and a case made of polyphenylene sulfide resin, and the terminal of the insulated cable hot melt adhered to the housing.

Description

Insulated cable, component for control system, and method for producing component for control system

Background technique

The present invention relates to an insulated cable having heat-melt adhesion to polyphenylene sulfide resin. In addition, the present invention relates to components for a control system installed in automobiles and a method for manufacturing the same, for example, components for a control system such as a sensor component having a case made of polyphenylene sulfide resin.

Various control systems installed in automobiles, etc. usually have: sensor components that convert physical quantities such as temperature, speed, and pressure into electrical signals; ECU (Electric Control Unit, electronic control unit) that calculates and processes signals generated by sensor components ; and the actuator parts that work according to the output signal of the ECU. Sensor parts, ECU, and actuator parts are connected to each other by cables that transmit signals. In an anti-lock braking system (ABS), which is one of such control systems, the sensor part is a wheel speed sensor provided near a wheel. The wheel speed sensor is used in the environment where the car is splashed with water. Therefore, not only the wheel side sensor is required to be waterproof, but also the connection between the sensor and the cable is required to be waterproof.

In terms of dimensional accuracy, mechanical strength, and formability, polyester resins such as PBT (polybutylene terephthalate), or 6-nylon, 6,6 - Polyamide resins such as nylon and 6T-nylon (aromatic nylon). In addition, polyphenylene sulfide resin (PPS), a heat-resistant engineering plastic with a melting point of about 280°C or higher, is used as a housing material for wheel speed sensors because it has excellent chemical resistance and flame retardancy.

On the other hand, an insulated cable in which an outer periphery of an insulated wire is covered with a sheath layer is used as a cable connecting the wheel speed sensor and the ECU. People not only require the sheath layer to have flexibility, abrasion resistance, bending resistance, water resistance, etc., but also require the connection between the sensor and the cable to be waterproof. Therefore, for example, as disclosed in Japanese Patent No. 3428391 and Japanese Unexamined Patent Application Publication No. 2006-156407, a method has been proposed in which a resin capable of heat-melt adhesion with engineering plastics forming the casing is used to form a The sheath layer is formed, and the housing and the sheath layer are thermally melted and adhered to seal during the injection molding of the housing.

In addition, in Japanese Patent No. 3428391 and Japanese Unexamined Patent Application Publication No. 2006-156407, as a resin satisfying the above-mentioned requirements, it is proposed to use a mixture of a thermoplastic polyurethane elastomer and a thermoplastic polyester elastomer as a main resin composition. conjoined body, or a cross-linked body of a resin composition mainly composed of a mixture of thermoplastic polyurethane elastomer and thermoplastic polyamide elastomer.

When the component ratio of the mixture contained in the cross-linked body of the resin composition is within a predetermined range, the cross-linked body of the resin composition can be thermally melt-adhered to the polyester resin or the polyamide resin. Therefore, when the case is made of these resins, the waterproofness of the connection portion can be ensured without using a sealing member such as an O-ring. However, a resin having excellent hot-melt adhesion to PPS has not yet been found. Therefore, as a material for forming the sheath layer of the cable, a suitable material capable of heat-melting adhesion to the PPS case is required.

Contents of the invention

The present invention provides an insulated cable that includes a sheath layer that is excellent in heat-melt adhesion to PPS, and by heat-melt-adhering the terminal portion of the cable to a case made of PPS, it is possible to secure the gap between the cable and the case. The connection part is waterproof. In addition, the present invention provides a component for a control system that is excellent in waterproofness at a connection portion between a cable and a housing, and a method for manufacturing the same.

The inventors of the present invention conducted intensive studies on the above-mentioned subject. As a result, it was found that a resin composition containing a thermoplastic polyester elastomer in a predetermined ratio or more has excellent hot-melt adhesiveness to PPS. The present inventors also found that, in the case of using PPS as the housing material, the waterproofness of the connection portion between the insulated cable and the housing can be maintained for a long period of time without impairing required properties such as abrasion resistance or bending resistance.

In order to achieve the above object, according to the first embodiment of the present invention, there is provided an insulated cable: it has a single-core or multi-core insulated wire, and a sheath layer formed on the outer periphery of the insulated wire, and it is used with polystyrene The thioether resin is thermally melt-adhered. According to the insulated cable of the present invention, the sheath layer is composed of a cross-linked resin composition, and the resin composition contains a thermoplastic polyester elastomer in an amount of 45% by weight or more of the entire resin composition.

According to the above structure, the sheath layer is composed of a cross-linked resin composition, and the resin composition contains thermoplastic polyester elastomer accounting for 45% by weight or more of the entire resin composition, so the heat exchange between the sheath layer and PPS can be increased. Melt adhesion.

The molding temperature of PPS is about 310 to 360° C., which is higher than the melting temperature of a resin composition containing 45% by weight or more of a thermoplastic polyester elastomer. Therefore, when the cable is hermetically connected while injecting the PPS to form the case, the sheath layer can be melted as long as crosslinking does not occur. Thereafter, the thermoplastic polyester elastomer-containing resin composition is crosslinked, thereby curing the sheath layer in a molten state. For example, in the molecule of trimethylolpropane trimethacrylate, triallyl cyanurate, or triallyl isocyanate, blending multifunctional monomers with multiple carbon-carbon double bonds, and using Crosslinking is performed by irradiating ionizing radiation such as accelerated electron beams or gamma rays.

In addition, a method different from the above-mentioned method, such as thermal vulcanization using an organic peroxide, or a water cross-linking method, wherein the water cross-linking method is to graft the above-mentioned mixture with an alkoxysilane in advance (graft ), and in the presence of a catalyst such as an organotin compound, the grafted material is contacted with water or steam to perform crosslinking. However, the method using ionizing radiation such as accelerated electron beams is simple and highly productive mainly from the viewpoint of the crosslinking treatment speed.

In the above-mentioned insulated cable, the proportion of the thermoplastic polyester elastomer in the resin composition is preferably more than 80% by weight.

In the resin composition constituting the sheath layer, when the proportion of the thermoplastic polyester elastomer exceeds 80% by weight, the hot-melt adhesiveness between the sheath layer and PPS is further improved. According to Japanese Patent No. 3428391 and Japanese Patent Application Laid-Open No. 2006-156407, the proportion of thermoplastic polyester elastomer in the resin composition is 80% by weight for hot melt adhesiveness with polyester resin or polyamide resin. The following are preferable. On the contrary, according to the present invention, it is preferable that the proportion of the thermoplastic polyester elastomer in the resin composition exceeds 80% by weight for hot-melt adhesiveness to PPS. Therefore, the constitution of the present application cannot be predicted at all from the conventional findings in the above-mentioned documents.

In the above insulated cable, the thermoplastic polyester elastomer is a block copolymer of a crystalline hard segment and an amorphous soft segment, wherein the amorphous soft segment is preferably a polyether polymer.

Examples of the crystalline hard segment include polymers such as polybutylene terephthalate (PBT). Examples of the amorphous soft segment include polymers composed of polyoxymethylene glycol such as polytetramethylene ether glycol, and polymers composed of polyester diol such as polycaprolactone glycol. As the amorphous soft segment, when a polyether-based polymer such as polyoxymethylene glycol is used, a molded article having excellent flexibility can be obtained, and thus such a polymer is preferably used.

In the above insulated cable, the resin composition preferably contains a thermoplastic polyurethane elastomer.

The resin composition constituting the sheath layer may contain other resin mixed with the thermoplastic polyester elastomer as long as the resin composition contains the thermoplastic polyester elastomer within the above ratio range. Examples of other resins include thermoplastic polyurethane elastomers, polyethylene and polypropylene copolymers and terpolymers, graft resins of these polymers, thermoplastic elastomers, plant-derived resins, and biodegradable resins. , engineering plastics, etc. Among these resins, thermoplastic polyurethane elastomers are preferable from the viewpoint of heat resistance, abrasion resistance, and the like.

Thermoplastic polyurethane elastomer is a polymer formed by chimera copolymerization of polyurethane hard segment and soft segment composed of bifunctional polyol. The polyurethane hard segment is composed of a condensation polymer formed of a diisocyanate such as toluene diisocyanate and a short-chain diol such as ethylene glycol. According to the type of soft segment, thermoplastic polyurethane elastomer can be divided into polyether, caprolactone, adipate, polycarbonate and other types.

In the above insulated cable, the resin composition forming the sheath layer is preferably selected from nitrogen-containing flame retardants, or ethylene bisbromophthalimide, bis(bromophenyl)ethane and dibromobenzene Flame retarded by one or more flame retardants in terephthalamide.

Thermoplastic polyester elastomers are flammable, so when preparing a flame-retardant cable, it is necessary to flame-retardant the sheath layer using the resin composition, or to flame-retardant the insulating layer or interlayer to form a flame-retardant layer on the sheath. Layer outside to ensure flame retardancy. As a method of ensuring flame retardancy, a method of blending a flame retardant is known. In this method, if the flame-retardant resin composition is applied to the sheath layer of the insulated cable of the present invention, JASO Possibility to pass combustion test of standard (Japan Automobile Manufacturers' Association) or ISO standard is high. That is, a highly secure cable can be obtained.

However, the bond strength after hot melt adhesion of the sheath layer to the shell material is affected by the type of flame retardant blended in the elastomer mixture. As a flame retardant, if nitrogen-containing flame retardants, or ethylene bisbromophthalimide, bis(bromophenyl)ethane and bis(bromophenyl)terephthalamide, etc. are used, Then the housing and the sheath layer can be firmly thermally melt-adhered. As a nitrogen-containing flame retardant, a melamine resin, a melamine cyanurate, etc. are mentioned, for example.

On the other hand, when a polybrominated diphenyl ether such as decabromodiphenyl ether or octabromodiphenyl ether is used as a flame retardant, the adhesive strength after thermal fusion bonding of the casing and the sheath layer may be insufficient.

The higher the degree of crosslinking of the resin composition forming the sheath layer, the greater the effect on the adhesive strength after thermal fusion adhesion due to the type of flame retardant. In the case of forming the sheath layer using a resin composition added with a polybrominated diphenyl ether such as decabromodiphenyl ether as a flame retardant, if the degree of crosslinking during injection molding is increased to the extent that the sheath layer can be reliably maintained If the level of the shape is low, the adhesive strength after the heat-melt adhesion of the shell and the sheath layer may not be obtained in some cases.

In contrast, flame retardants such as nitrogen-containing flame retardants, ethylene bisbromophthalimide, bis(bromophenyl)ethane or bis(bromophenyl)terephthalamide In the case of injection molding, even if the degree of cross-linking is increased to a level where the shape of the sheath layer can be reliably maintained, the case and the sheath layer can be firmly bonded by thermal fusion, so that desired waterproof performance can be obtained. In addition, there is an advantage that when a nitrogen-containing flame retardant (especially melamine cyanurate) is blended into a resin such as polyurethane elastomer, it is difficult to decompose even under high temperature conditions.

Various stabilizers such as antioxidants, light stabilizers, and hydrolysis inhibitors, or known reinforcing agents, fillers, and colorants, etc., may be added to the resin composition constituting the sheath layer without departing from the scope of the present invention. of blended chemicals.

The above-mentioned components can be prepared into a resin composition constituting the sheath layer using known mixers such as internal mixers, pressure kneaders, single-screw mixers, twin-screw mixers, and open roll mills.

In order to achieve the above objects, according to a second embodiment of the present invention, there is provided a component for a control system that includes the above-mentioned insulated cable and a case made of polyphenylene sulfide resin, and in which the terminal portion of the insulated cable is thermally melt-bonded. attached to the housing.

The above-mentioned insulated cable is excellent in hot-melt adhesiveness to PPS. Therefore, the waterproofness of the connection portion between the insulated cable and the PPS case can be ensured. Therefore, a component for a control system having excellent water resistance can be obtained.

In order to achieve the above object, according to a third embodiment of the present invention, there is provided a method of manufacturing a component for a control system, wherein polyphenylene sulfide resin is injected into a mold containing the terminal portion of the above-mentioned insulated cable to form a housing, And the housing is thermally melt-adhered to the insulating cable terminal portion to be sealed.

By injecting PPS into the molding die provided with the terminal part of the insulating cable, the cross-linked body of the resin composition constituting the sheath layer and the shell material are thermally melted and adhered, so that the connection part between the cable and the shell can be made seal. According to this manufacturing method, the component for a control system of the present invention can be manufactured at low cost through a simple process, and the process of attaching a sealing member is not required. As the conditions for injection molding, the same conditions as those for PPS injection molding can be employed.

A brief description of the drawings

Fig. 1 is a cross-sectional view showing an example of the use state of the insulated cable of the present invention (control system component: wheel speed sensor),

Fig. 2 is an enlarged oblique view showing an example of the insulated cable of the present invention, and

Fig. 3 is a schematic perspective view showing how to arrange samples when measuring peel strength.

Best Embodiment of the Invention

Embodiments of the invention (particularly the best mode) will be described in more detail below with reference to the drawings and reference examples. However, the present invention is not limited to these aspects or reference examples, and changes can be made within a range not departing from the intent of the present invention.

FIG. 1 is a cross-sectional view showing an example of a state of use of the insulated cable of the present invention (component for a control system: wheel speed sensor). A in Figure 1 is an insulated cable. As shown in FIG. 2, the insulated cable A is a multi-core cable including two insulated wires a. The outer peripheries of the two insulated wires a are covered by the intermediate layer c. The outer periphery of the intermediate layer c is covered by the sheath layer b. Examples of the insulated cable of the present invention include a single-core cable including one insulated wire, or a cable not including an intermediate layer.

The sheath layer b is formed using a resin composition containing 45% by weight or more of a thermoplastic polyester elastomer. In addition, the method is the same as that of an ordinary insulated cable, that is, the middle layer c and the sheath layer b are used to form the sheath layer b. After covering the insulated wire, the sheath layer b is cross-linked to obtain an insulated cable A. For example, using a melt extruder, the materials forming the intermediate layer c and the sheath layer b are co-extruded to coat the insulated wire, thereby forming the intermediate layer c and the sheath layer b.

C in Figure 1 is the wheel speed sensor. The wheel speed sensor is accommodated in the housing H. As shown in FIG. The insulated wire a of the insulated cable A is connected to the output terminal d of the wheel speed sensor C. The sheath layer b of the insulated cable A is adhered to the connection portion B of the housing H by heat fusion. Excellent water resistance between the sheath layer b and the connection portion B of the case H can be ensured by thermal fusion adhesion. This structure can be obtained by setting the wheel speed sensor C in a molding die after connecting the insulated electric wire a to the output terminal d, injecting the casing material to cover the outer circumference of the terminal portion of the insulated cable A, and performing take shape.

In the above-mentioned embodiment, the wheel speed sensor has been described as an example of the components for the control system, but as another example, a knock sensor can be mentioned. The insulated cable A of the present invention is electrically connected to the piezoelectric element set in the main body mold, and then a PPS case material is injected to cover the piezoelectric element and the outer periphery of the terminal portion of the insulated cable A, and shaped to obtain Knock sensor.

(reference example)

First, the components shown below were blended in proportions (weight ratios) shown in Tables 1-2. Then, mixing was carried out in a high-temperature roller, and the mixture was shaped into a strip to form a sample piece. Then, the strip-shaped sample piece was hot-pressed to form a sheet having a thickness of 1 mm. Finally, the sheet was irradiated with an electron beam at an accelerating voltage of 120 kGy to 180 kGy to perform crosslinking, thereby manufacturing a resin composition sheet.

(blend ingredients)

·Thermoplastic polyester elastomer:

The hard segment is polybutylene terephthalate (PBT), and the soft segment is a polyether type of polytetramethylene glycol. Melting point: 168°C, JIS (or according to ISO 868) hardness: 40D

· Thermoplastic polyurethane elastomer:

Polyether type, JIS (or according to ISO 868) A hardness: 85±2A

Antioxidant: 2,2,4-trimethyl-1,2-dihydroquinoline polymer: amine-ketone antioxidant

Anti-decomposition agent: anti-decomposition agent mainly composed of aromatic polycarbodiimide

Carbon: carbon with an arithmetic mean particle size of 27nm

Lubricant: ester wax partially saponified by montanic acid

·Crosslinking agent: trimethylolpropane trimethacrylate

Using an injection molding machine (SE18D) manufactured by Sumitomo Heavy Industries, under the conditions of an injection temperature of 360° C. and a holding pressure of 250 Kgf, PPS was injected and melt-adhered to the resin composition sheet produced as described above. Thereafter, as shown in FIG. 3 , the peel strength was measured by pulling the resin composition sheet at a pulling speed of 50 mm/min using a pull tester (AGS10kND manufactured by Shimadzu Corporation). The measurement results are shown in Table 1 and Table 2.

(Table 1)

serial number 1 2 3 4 5 Thermoplastic Polyurethane Elastomer 100 90 70 60 50 Thermoplastic polyester elastomer 0 10 30 40 50 Antioxidant 1 1 1 1 1 Waterproof agent 2 2 2 2 2 carbon 2 2 2 2 2 lubricant 0.5 0.5 0.5 0.5 0.5 Crosslinking Auxiliary 5 5 5 5 5 Peel strength [N/cm] 2.2 2.5 3.7 8.1 14.0

(Table 2)

serial number 6 7 8 9 10 Thermoplastic Polyurethane Elastomer 40 30 20 10 0 Thermoplastic polyester elastomer 60 70 80 90 100 Antioxidant 1 1 1 1 1 Waterproof agent 2 2 2 2 2 carbon 2 2 2 2 2 lubricant 0.5 0.5 0.5 0.5 0.5 Crosslinking Auxiliary 5 5 5 5 5 Peel strength [N/cm] 14.4 16.6 22.4 29.5 35.7

As shown in Table 1 and Table 2, the peel strength of the crosslinked body of the resin composition containing 50 weight% or more of thermoplastic polyester elastomers and PPS was high. From this result, it can be seen that when the sheath layer of the insulated cable is composed of a cross-linked body of a resin composition containing 45% by weight or more of a thermoplastic polyester elastomer, the heat-melt adhesiveness of the insulated cable and the PPS casing excellent. Among them, in Nos. 8 to 10 in which the thermoplastic polyester elastomer is 80% by weight or more, the peel strength is particularly high. The results of Nos. 8 to 10 show that the hot-melt adhesiveness between the insulated cable and the case made of PPS is particularly excellent by using a resin composition in which the thermoplastic polyester elastomer is 80% by weight or more.

Claims (7)

1. insulated cable, the restrictive coating that this insulated cable has the insulated electric conductor of single core or multicore and is formed on described insulated electric conductor periphery, and this insulated cable is used for and the polyphenylene sulfide heat fusing adheres to, and it is characterized in that,

Described restrictive coating is made of the crosslinked body of resin combination, contains in the described resin combination to account for the above thermoplastic polyester elastomer of 45 overall weight % of this resin combination.

2. the described insulated cable of claim 1 is characterized in that, with respect to described resin combination, the ratio of thermoplastic polyester elastomer surpasses 80 weight %.

3. claim 1 or 2 described insulated cables is characterized in that, described thermoplastic polyester elastomer is the hard section of crystalline state and the block copolymer of soft section of amorphous state, and wherein said amorphous state is the polyethers polymer for soft section.

4. claim 1 or 2 described insulated cables is characterized in that, contain TPUE in the described resin combination.

5. claim 1 or 2 described insulated cables, it is characterized in that, form the selected self-contained nitrogen combustion inhibitor of resin combination of restrictive coating or one or more fire retardantizations in two bromine phthalimide, two (bromo phenyl) ethane of ethylene and the dibromo-benzene base terephthalamide.

6. control system parts is characterized in that, have the housing of claim 1 or 2 described insulated cables and polyphenylene sulfide system, and the terminal part heat fusing of described insulated cable sticks on the described housing.

7. a manufacturing control system is with the method for parts, it is characterized in that, polyphenylene sulfide injected in the mould that contains claim 1 or 2 described insulated cable terminal parts and be configured as housing, and described housing and described insulated cable terminal part heat fusing are adhered to sealing.

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