Insulating composition, and vehicle signal control cable comprising insulating layer formed therefrom

Abstract

The present invention relates to an insulating composition and a vehicle signal control cable comprising an insulating layer formed therefrom. Specifically, the present invention relates to: an insulating composition that satisfies the mechanical properties, weather resistance, long-term reliability, durability, and the like required of a single product and a composite cable of a wheel speed sensor (WSS) cable for a vehicle; and a vehicle signal control cable comprising an insulating layer formed therefrom.

Description

Cable for automotive signal control comprising an insulating composition and an insulating layer formed therefrom

[0001] The present invention relates to an automotive signal control cable comprising an insulating composition and an insulating layer formed therefrom. Specifically, the present invention relates to an automotive signal control cable comprising an insulating composition that satisfies all of the mechanical properties, weather resistance, long-term reliability, durability, etc. required for single and composite automotive WSS (Wheel Speed ​​Sensor) cables, and an insulating layer formed therefrom.

[0002] Wheel Speed ​​Sensor (WSS) cables are used to detect, signal, and transmit the speed of a vehicle's rotating wheels. Conventionally, WSS cables have been supplied and used as single-piece cables, consisting of two insulated cores with a urethane jacket.

[0003] However, recently, in order to realize various advantages such as reduction of connector interface, it has been developed and widely used in the form of a composite cable combined with a power transmission cable of an electronic parking brake (EPB).

[0004] Fig. 1 illustrates one embodiment of a cross-section of a conventional WSS / EPB composite cable. As illustrated in Fig. 1, a WSS cable including a pair of WSS cores (10) each composed of a conductor (11) and an insulator (12) wrapping the conductor (11) and a WSS jacket (20) wrapping the pair of WSS cores (10), and an EPB cable including a pair of EPB cores (30) each composed of a conductor (31) and an insulator (32) wrapping the conductor (31), may have a structure in which the entirety is wrapped with a composite cable jacket (40).

[0005] However, WSS cables have some differences in the required characteristics between single-piece and composite cables. For example, while WSS single-piece cables must meet most of the mechanical and environmental characteristics required for typical automotive harness wires, WSS / EPB composite cables primarily require long-term reliability and durability testing, typically involving various types of cable bending tests. While WSS single-piece cables also undergo bending tests, they are limited to room temperature testing, and the passing standards are lower than those for composite cables.

[0006] Accordingly, there is an urgent need for an automotive signal control cable comprising an insulating composition that satisfies all of the mechanical properties, weather resistance, long-term reliability, durability, etc. required for single and composite cables of an automotive WSS (Wheel Speed ​​Sensor) cable, and an insulating layer formed therefrom.

[0007] The purpose of the present invention is to provide an automotive signal control cable comprising an insulating composition that satisfies all of the mechanical properties, weather resistance, long-term reliability, durability, etc. required for single and composite cables of an automotive WSS (Wheel Speed ​​Sensor) cable, and an insulating layer formed therefrom.

[0008] In order to solve the above problem, the present invention,

[0009] An insulating composition comprising a base resin and a flame retardant, wherein the base resin comprises a high-melting-point resin having a relatively high melting point and a low-melting-point resin having a relatively low melting point, and the total melting enthalpy of the insulating composition defined by the following mathematical formula 1 is 25 to 50 J / g,

[0010] [Mathematical Formula 1]

[0011]

[0012] An insulating composition is provided, wherein the melting enthalpy ratio of a low-melting-point resin defined by the following mathematical formula 2 is 4 to 40%.

[0013] [Equation 2]

[0014]

[0015] In the above mathematical equations 1 and 2,

[0016] △H is the total melting enthalpy of the insulating composition measured by differential scanning calorimetry (DSC),

[0017] △H1 is the melting enthalpy of low-melting-point resin,

[0018] △H2 is the melting enthalpy of high-melting-point resin.

[0019] Here, an insulating composition is provided, characterized in that the low-melting-point resin has a melting point of 60 to 100°C, and the high-melting-point resin has a melting point of 105 to 135°C.

[0020] In addition, an insulating composition is provided, characterized in that the low-melting-point resin includes ethylene vinyl acetate (EVA) resin, and the high-melting-point resin includes linear low-density polyethylene (LLDPE) resin.

[0021] Meanwhile, the present invention provides an insulating composition characterized in that the base resin additionally includes a linear low-density polyethylene resin grafted with a polar group as a commercial resin.

[0022] Here, an insulating composition is provided, characterized in that, based on 100 parts by weight of the base resin, the content of the low-melting-point resin is 20 to 60 parts by weight, the content of the high-melting-point resin is 30 to 70 parts by weight, and the content of the compatibilizer resin is 5 to 20 parts by weight.

[0023] And, an insulating composition is provided, characterized in that the cross-linking degree is 50% or more.

[0024] Meanwhile, an insulating composition is provided, characterized in that the flame retardant comprises an inorganic metal hydroxide.

[0025] Here, an insulating composition is provided, characterized in that the inorganic metal hydroxide includes magnesium hydroxide or aluminum hydroxide, and the content of the inorganic metal hydroxide is 60 to 110 parts by weight based on 100 parts by weight of the base resin.

[0026] Meanwhile, a wheel speed sensor cable for an automobile is provided, comprising a conductor; and at least one core comprising an insulator formed from the insulating composition and surrounding the conductor.

[0027] In addition, a composite cable including the above-described wheel speed sensor cable for an automobile and an electric parking brake (EPB) cable is provided.

[0028] The insulating composition according to the present invention comprises two types of resins, a high-melting-point resin and a low-melting-point resin, as base resins, and by controlling the total melting enthalpy of the insulating composition and the ratio of melting enthalpies between the two types of resins, it exhibits excellent effects that satisfy mechanical properties, weather resistance, long-term reliability, durability, etc.

[0029] Figure 1 illustrates one embodiment of a cross-section of a conventional WSS / EPB composite cable.

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosure is thorough and complete, and to sufficiently convey the spirit of the present invention to those skilled in the art. Like reference numbers designate like elements throughout the specification.

[0031] The present invention relates to an insulating composition for forming an insulating layer of a WSS cable that satisfies all of the properties required for a composite cable with a single cable for a wheel speed sensor (WSS) and a cable for an electronic parking brake (EPB) used for the purpose of detecting the speed of a rotating wheel of an automobile and converting and transmitting the same.

[0032] The conventional 120℃ class WSS cable to which the insulating composition according to the present invention is applied is based on a cross-linked polyethylene resin as an insulator, but could not satisfy the characteristics required for the product due to reasons such as single application of the polyethylene resin, inappropriate use of other additives, or insufficient content.

[0033] In particular, for WSS single cables, in addition to basic mechanical properties, they must also contain a certain level of flame retardant to satisfy flame retardancy performance according to Article 5.9 of the standard JASO D608-92, and for WSS / EPB composite cables, they must also satisfy the flexibility test required by Article 5.9 of the standard ISO 14572.

[0034] In addition, in order to satisfy the heat resistance performance required for a 120℃ class cable, a certain level of cross-linking must be achieved after cross-linking, and this is a very important evaluation item in terms of the long-term reliability of the product.

[0035] In this situation, the inventors of the present invention experimentally confirmed that all the properties required for WSS single products and composite cables are satisfied by applying two types of base resins including a high-melting-point resin having a relatively high melting point and a low-melting-point resin having a relatively low melting point as base resins, and in particular, by controlling the ratio of the low-melting-point resin of the melting enthalpy of the two types of base resins defined by the following mathematical formula 1 to 4 to 40%, and thereby completing the present invention.

[0036] [Mathematical Formula 1]

[0037]

[0038] [Equation 2]

[0039]

[0040] In the above mathematical equations 1 and 2, △H is the total melting enthalpy of the insulating composition measured by differential scanning calorimetry (DSC), △H1 is the melting enthalpy of the low-melting-point resin, and △H2 is the melting enthalpy of the high-melting-point resin.

[0041] Here, when △H defined by the above mathematical formula 1 is less than 25 J / g, the durability of the insulating composition is greatly reduced, and the wear resistance is below the standard, and when △H exceeds 50 J / g, the filler loading property of the insulating composition, such as a flame retardant, is greatly reduced, and the elongation, flexibility, etc. are reduced, and as a result, the composition does not pass the room temperature and low temperature reciprocating test.

[0042] In addition, when the △H ratio defined by the above mathematical formula 2 is less than 4%, the flexibility of the insulating composition is greatly reduced, and it does not pass the room temperature and low temperature reciprocating test, and when the △H ratio exceeds 40%, the crystallinity of the insulating composition is greatly reduced, and the room temperature strength and wear resistance do not meet the standards.

[0043] For example, the low-melting-point resin may include an ethylene copolymer resin having a melting point (Tm) of 60 to 100°C, preferably an ethylene vinyl acetate (EVA) resin, an ethylene ethyl acrylate (EEA) resin, and more preferably an ethylene vinyl acetate (EVA) resin, and the high-melting-point resin may include a polyethylene resin having a melting point (Tm) of 105 to 135°C, preferably a high-density polyethylene (HDPE) resin, a low-density polyethylene (LDPE) resin, a linear low-density polyethylene (LLDPE) resin, and more preferably a linear low-density polyethylene resin.

[0044] In addition, the insulating composition may additionally include a linear low-density polyethylene resin grafted with a polar group such as maleic anhydride as a compatibilizer resin to improve compatibility with the base resin and the additive.

[0045] For example, based on 100 parts by weight of the base resin, the content of the low-melting-point resin is 20 to 60 parts by weight, the content of the high-melting-point resin is 30 to 70 parts by weight, and the content of the compatibilizer resin is 5 to 20 parts by weight.

[0046] Furthermore, the insulating composition can be crosslinked through crosslinking to secure mechanical properties, wear resistance, heat resistance, etc., and the degree of crosslinking can be controlled to 50% or more during crosslinking.

[0047] Meanwhile, the insulating composition may include a flame retardant to implement flame retardant performance according to Article 5.9 of the standard JASO D608-92, and the flame retardant may include an inorganic metal hydroxide such as magnesium hydroxide or aluminum hydroxide. The metal hydroxide may have a surface that is hydrophobic to improve compatibility with the base resin, and may be included in an amount of 60 to 110 parts by weight based on 100 parts by weight of the base resin. In addition, a halogen flame retardant and an antimony flame retardant may also be used if there is no separate requirement such as halogen-free.

[0048] Furthermore, the insulating composition may additionally include other additives such as an antioxidant, a crosslinking agent, and a lubricant in addition to the base resin and the flame retardant.

[0049] Accordingly, the insulating composition according to the present invention exhibits excellent effects that satisfy all of the mechanical properties, weather resistance, long-term reliability, durability, etc. required for single and composite cables of WSS (Wheel Speed ​​Sensor) cables for automobiles.

[0050]

[0051] <Example>

[0052]

[0053] 1. Manufacturing example

[0054]

[0055] An insulating composition was prepared with the components and contents listed in Table 1 below. The unit of contents listed in Table 1 below is parts by weight.

[0056]

[0057] Example Comparative Example 1 2 3 4 5 6 1 2 3 4 5 Resin 1 7 0 8 0 8 5 Resin 2 6 0 5 0 Resin 3 5 0 4 0 3 0 2 0 1 5 Resin 4 7 0 Resin 5 2 0 1 0 5 2 0 Resin 6 3 0 4 0 Resin 7 4 0 5 0 6 0 7 0 7 5 Resin 8 1 0 ... .633.03△H2J / g38.2433.6422.1621.6020.5419.3651.1152.9117.3813.1019.11△H1+△H2J / g41.2138.3328.0229.5231.1531.1953.0054.4831.0427.7322.14△H ratio%7.212.220.926.834.137.93.62.944.052.813.7

[0058]

[0059] - Resin 1: High-density polyethylene (melting point: 130℃)

[0060] - Resin 2: Linear low-density polyethylene (melting point: 120℃)

[0061] - Resin 3: Low-density polyethylene (melting point: 110℃)

[0062] - Resin 4: Low-density polyethylene (melting point: 105℃)

[0063] - Resin 5: Ethylene ethyl acrylate (melting point: 97℃)

[0064] - Resin 6: Ethylene vinyl acetate (melting point: 85℃)

[0065] - Resin 7: Ethylene vinyl acetate (melting point: 71℃)

[0066] - Resin 8: Maleic anhydride grafted linear low-density polyethylene (melting point: 120℃)

[0067] - Flame retardant: magnesium hydroxide

[0068]

[0069] 2. Physical property evaluation

[0070]

[0071] 1) Evaluation of room temperature tensile strength and elongation

[0072] For the insulating specimens manufactured from each insulating composition of the examples and comparative examples, the tensile strength and elongation were measured at a tensile speed of 200 mm / min in accordance with Article 5.5 of the standard JASO D608-92. The tensile strength must be 10.3 MPa or more, and the elongation must be 150% or more.

[0073] 2) Wear resistance evaluation

[0074] For WSS single cable specimens having an insulating layer formed from each insulating composition of the examples and comparative examples, abrasion resistance was evaluated in accordance with the standard JASO D608-92, Article 5.11(1), and the evaluation result showed that durability of 300 mm or more must be secured.

[0075] 3) Flame retardancy evaluation

[0076] A horizontal flame retardancy test was performed on WSS single cable specimens having an insulation layer formed from each of the insulating compositions of the examples and comparative examples in accordance with Article 5.9 of the standard JASO D608-92, and the evaluation result is that the flame must be extinguished within 30 seconds after being applied for 10 seconds.

[0077] 4) Low-temperature evaluation

[0078] A low-temperature winding test at -45°C was performed on WSS single cable specimens having an insulating layer formed from each insulating composition of each of the examples and comparative examples in accordance with standard JASO D608, clause 5.8, and the evaluation result was that there should be no cracks visible to the naked eye.

[0079] 5) Heat resistance evaluation

[0080] A short-term heat resistance test was performed at 150°C for 240 hours on WSS single cable specimens having an insulating layer formed from each insulating composition of each of the examples and comparative examples in accordance with JASO D608, Article 5.7(1), and the evaluation result was that there should be no cracks visible to the naked eye.

[0081] 6) Bridge evaluation

[0082] For WSS single cable specimens having an insulating layer formed from each insulating composition of the examples and comparative examples, the degree of cross-linking of the insulation was evaluated in accordance with the standard JASO D608, clause 5.12, and the evaluation result satisfies that the degree of cross-linking must be 50% or more.

[0083] 7) 90 degree reciprocating flexibility evaluation

[0084] For composite cable specimens in which a WSS cable and an EPB cable having an insulation layer formed from each of the insulating compositions of Examples and Comparative Examples are combined, a 90-degree reciprocating bending test was performed at room temperature and low temperature (-35°C) in accordance with Article 5.9 of the standard ISO 14572 (2011). In the case of the room temperature test, a bending performance of 100,000 or more times must be secured, and in the case of the low temperature test, a bending performance of 10,000 or more times must be secured.

[0085]

[0086] The results of the above property evaluation are as described in Table 2 below.

[0087]

[0088] Material property standard implementation preliminary comparison example 12345612345 Tensile strength 10.3 MPa or more 16.115.815.514.213.811.518.1120.49.329.0210.93 Elongation 150% or more 1621751781892012138982280291215 Wear resistance 300 mm or more 562.5525525487.5450412.5637.5656.25243.75225281.25 Flame retardancy Within 30 seconds 1113151413171416121815 Low temperature resistance No Crack No No No No No No No No No No No Heat resistance No CrackNoNoNoNoNoNoNoNoNoNoNo90 degreesReciprocating flexibilityRoom temperature100,000 times or more120,689125,620136,324131,435120,234142,01398,10293,031159,021163,920145,729-35℃10,000 times or more12,22113,35214,08515,48213,20315,4259,2018,81015,49016,12013,950

[0089]

[0090] As described in Table 2 above, the insulating compositions of Examples 1 to 6, in which the total melting enthalpy of the insulating composition and the melting enthalpy ratio of the low-melting-point resin were appropriately controlled, were confirmed to have excellent room-temperature mechanical properties, wear resistance, flame retardancy, low-temperature properties, heat resistance, and flexibility.

[0091] On the other hand, the insulating compositions of Comparative Examples 1 and 2, in which the total melting enthalpy of the insulating composition exceeded 50 J / g and the melting enthalpy ratio of the low-melting-point resin was less than 4%, showed greatly reduced room temperature elongation, flexibility, and bendability, and the insulating compositions of Comparative Examples 3 and 4, in which the total melting enthalpy of the insulating composition was appropriate but the melting enthalpy ratio of the low-melting-point resin exceeded 40%, showed greatly reduced room temperature tensile strength and wear resistance, and the insulating composition of Comparative Example 5, in which the total melting enthalpy of the low-melting-point resin was appropriate but the total melting enthalpy of the insulating composition was less than 25 J / g, showed greatly reduced wear resistance.

[0092] While this specification has described preferred embodiments of the present invention, those skilled in the art will appreciate that various modifications and variations can be made to the present invention without departing from the spirit and scope of the invention as defined in the claims below. Therefore, any modified implementation that fundamentally includes the elements of the claims should be considered within the technical scope of the present invention.

Claims

1. As an insulating composition, Contains base resin and flame retardant, The above base resin includes a high-melting-point resin having a relatively high melting point and a low-melting-point resin having a relatively low melting point, The total melting enthalpy of the insulating composition defined by the mathematical formula 1 below is 25 to 50 J / g, [Mathematical Formula 1] An insulating composition having a melting enthalpy ratio of a low-melting-point resin defined by the following mathematical formula 2 of 4 to 40%. [Equation 2] In the above mathematical equations 1 and 2, △H is the total melting enthalpy of the insulating composition measured by differential scanning calorimetry (DSC), △H1 is the melting enthalpy of low-melting-point resin, △H2 is the melting enthalpy of high-melting-point resin.

2. In paragraph 1, The above low-melting-point resin has a melting point of 60 to 100°C, An insulating composition, characterized in that the high-melting point resin has a melting point of 105 to 135°C.

3. In paragraph 2, The above low-melting point resin includes ethylene vinyl acetate (EVA) resin, An insulating composition, characterized in that the high-melting point resin comprises linear low-density polyethylene (LLDPE) resin.

4. In any one of paragraphs 1 to 3, An insulating composition characterized in that the base resin further comprises a linear low-density polyethylene resin grafted with a polar group as a compatibilizer resin.

5. In paragraph 4, An insulating composition characterized in that, based on 100 parts by weight of the base resin, the content of the low-melting-point resin is 20 to 60 parts by weight, the content of the high-melting-point resin is 30 to 70 parts by weight, and the content of the compatibilizer resin is 5 to 20 parts by weight.

6. In any one of paragraphs 1 to 3, An insulating composition characterized by a cross-linking degree of 50% or more.

7. In any one of paragraphs 1 to 3, An insulating composition characterized in that the flame retardant comprises an inorganic metal hydroxide.

8. In paragraph 7, The above inorganic metal hydroxide includes magnesium hydroxide or aluminum hydroxide, An insulating composition characterized in that the content of the inorganic metal hydroxide is 60 to 110 parts by weight based on 100 parts by weight of the base resin.

9. Conductor; and An automotive wheel speed sensor cable comprising at least one core comprising an insulator formed from an insulating composition according to any one of claims 1 to 3, wherein the core comprises a conductor.

10. Wheel speed sensor cable for automobiles of Article 9; and Composite cable including electric parking brake (EPB) cable.

Images