KR102620352B1 - Industrial cable with high heat resistance and high flexibility and no blooming - Google Patents

Abstract

The present invention relates to 100 parts by weight of a base resin consisting of 30 to 40% by weight of ethylene propylene diene monomer (EPDM) to which no crosslinking agent is added, 30 to 50% by weight of ethylene vinyl acetate resin, and 20 to 40% by weight of polyolefin elastomer: Flame retardant. It relates to an industrial cable characterized by comprising 50 to 78 parts by weight, 1 to 5 parts by weight of a crosslinker, and 1 to 5 parts by weight of an antioxidant. The industrial cable according to the present invention has flexibility including high flexibility at room temperature and high flexibility at low temperature. It has excellent heat resistance and high flame resistance that can withstand high temperatures, and it can prevent problems with quality deterioration by preventing blooming and bleeding phenomena that tend to occur on the surface due to chronic problems in products containing irradiation crosslinking agents.

Description

Industrial cable with high heat resistance and high flexibility and no blooming {Industrial cable with high heat resistance and high flexibility and no blooming}

The present invention relates to an industrial cable that has high heat resistance and high flexibility and does not cause blooming. Specifically, it has excellent flame resistance and heat resistance characteristics and flexibility without causing blooming due to the use of EPDM rubber and irradiation crosslinking agent. It concerns industrial cables that can be secured and used for various purposes.

In the automobile industry, vehicle weight is continuously increasing due to strengthened safety regulations and increased convenience specifications, and accordingly, there is a demand for lighter electronic components. When high-voltage cables are added to eco-friendly cars, the weight of the wires further increases, so there is a greater need for improved performance and lighter car cables. In addition, in addition to lightweighting, various functions such as flexibility, heat resistance, insulation, and flame retardancy are required.

Existing thermoplastic elastomer (TPE) materials have excellent flexibility, but have the disadvantage of not being flame retardant or heat resistant. Among them, ethylene-propylene rubber (Ethylene Propylene Diene terpolymer, hereinafter referred to as '') was used as the main base resin.

The EPDM is a polymer material that has a certain amount of unsaturated diene units and is composed of repeating units of ethylene and propylene, so it has excellent insulation performance because it has no polar group, and exhibits excellent oxidation resistance and ozone resistance properties. EPDM rubber is less expensive than many other elastomers, can contain high concentrations of fillers and oils, and has excellent physical properties. For this reason, EPDM can be blended with other elastomers or additives to achieve heat resistance, flexibility, and flame retardancy properties.

Looking at the prior art using EPDM rubber for cables, Korean Patent No. 10-0635586 uses 40 to 80 parts by weight of ethylene vinyl acetate copolymer (EVA) and 10 to 50 parts by weight of ethylene propylene diene (EPDM) copolymer. It contains 30 to 170 parts by weight of a flame retardant based on 100 parts by weight of a base resin made of a mixture of 5 to 20 parts by weight of partially and modified ethylene vinyl acetate (EVA), and the ethylene vinyl acetate copolymer contains 10 parts by weight of vinyl acetate. % to 40% by weight, the ethylene propylene diene copolymer contains 40% to 85% by weight ethylene and 0.5% to 7.5% by weight diene, and the modified ethylene vinyl acetate copolymer contains vinyl acetate. A flame retardant and cut-through resistant resin composition was presented, which is 10% to 30% by weight and has a polar group introduced into the terminal group.

In addition, Korean registered patent 10-1918755 contains 30 to 80 phr of EPDM (Ethylene Propylene Diene Monomer) with no crosslinking agent added, 10 to 50 phr of PO (Polyolefine) resin, 5 to 40 phr of silicone rubber, 20 to 30 phr of flame retardant, and 5 to 10 phr of crosslinking accelerator. , 1 to 5 phr of crosslinking aid, 5 to 15 phr of antioxidant, and 0.25 to 5 phr of lubricant are added, and the EPDM satisfies the requirement of having an ENB (Ethylene-norbornene) content of 2.5 to 5% by weight and has a Mooney viscosity of 22. Among those satisfying the requirements of ~65, hardness shore A of 59~90, and TR-10 of -10~-12, singly or two types are mixed, and the PO resin is a partially cross-linked modified resin. PO and EPR (Ethylene-Propylene Rubber) are mixed, and the flame retardant is Al(OH)3, Mg(OH)2 alone or a mixture of the two, or Br-based, whose surface is coated with silane. A irradiation cross-linked EPDM composition characterized as a flame retardant was presented.

In the case of wires using existing EPDM rubber, chemical cross-linking was often used, resulting in the generation of methane gas, which had a negative environmental impact. However, by changing this to the irradiation cross-linking method as in the above patent, methane gas generation can be reduced. , the problem of quality deterioration caused by cross-linking by-products was also solved.

However, when blending TPE materials with elastomers and additives as in the above patent, depending on the surrounding environment (temperature and humidity, etc.) or when irradiation crosslinking agents are included, the solid or liquid additives have limited solubility in the polymer matrix. Blooming is a phenomenon that occurs due to surface migration, in which the compound seeps into the rubber surface and creates a flower-shaped pattern; Alternatively, there is a problem of bleeding phenomenon, which occurs when some additives float to the top due to separation of materials. Some blooming and bleeding phenomena may occur on purpose in special cases in foreign countries to protect rubber, but in general, the aesthetics are not good and there is a high possibility of quality deterioration, so development to prevent this is necessary.

In addition, the existing 125℃ heat resistance grade is insufficient for heat resistance, so properties of 150℃ or higher are required, and heat resistance from -40℃ to 150℃ is required for use in extremely cold areas. In particular, cables located in automobile engine parts are exposed to adverse physical or chemical conditions such as high temperature, oil, vibration, and narrow spaces, so high heat resistance and high flexibility are required, but the development of wires that meet these requirements is still insufficient. am.

In addition, due to the risk of damage to life and property due to fire, high flammability and smoke density tests are necessary, and for these tests, it is necessary to develop wires that not only secure heat resistance but also have high flammability.

Korean registered patent 10-0635586 Korean registered patent 10-1918755

Accordingly, the purpose of the present invention is to provide an industrial cable that has high heat resistance, high flexibility, and high flammability that can be used not only in automobiles but also in the entire industry and does not cause blooming or bleeding phenomena.

The industrial cable according to the present invention is 100 parts by weight of a base resin consisting of 30 to 40% by weight of ethylene propylene diene monomer (EPDM) without any crosslinking agent, 30 to 50% by weight of ethylene vinyl acetate resin, and 20 to 40% by weight of polyolefin elastomer. Regarding: It is characterized in that it contains 50 to 78 parts by weight of a flame retardant, 1 to 5 parts by weight of a crosslinking agent, and 1 to 5 parts by weight of an antioxidant.

According to one embodiment of the present invention, the ethylene propylene diene monomer (EPDM) to which the crosslinking agent is not added preferably has a Mooney Viscosity value of 60 to 80.

According to one embodiment of the present invention, the ethylene vinyl acetate resin preferably has a vinyl acetate content of 40 to 70% by weight.

In addition, the flame retardant of the present invention is selected from aluminum hydroxide (Al(OH) ₃ , S-ATH) with a silane-coated surface or magnesium hydroxide (Mg(OH) ₃ , S-MDH) with a silane-coated surface. It may be used alone or in combination.

According to one embodiment of the present invention, the crosslinking agent is triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), and trimethylolpropane trimethacrylate (TMPTMA). , and trimethylolpropane triacrylate (TMPTA).

The industrial cable according to the present invention has excellent flexibility, including high flexibility at room temperature and high flexibility at low temperature, and has high heat resistance and high flame retardancy characteristics that can withstand high temperatures, and is prone to surface formation due to a chronic problem with products containing irradiation crosslinking agents. By preventing blooming and bleeding phenomena, problems with quality deterioration can be prevented.

Therefore, the industrial cable according to the present invention is exposed to adverse physical or chemical conditions such as high temperature, oil, vibration, and narrow spaces, so it is used as a cable for the engine part of an automobile, which requires high heat resistance and high flexibility, as well as for agricultural equipment and charging cables. It can be used for various purposes, such as for high voltage cables and battery cables.

The present invention will be described in more detail below.

The terms used herein are used to describe specific embodiments and are not intended to limit the invention.

As used herein, the singular forms include the plural forms unless the context clearly indicates otherwise. Additionally, when used herein, “comprise” and/or “comprising” means specifying the presence of stated features, numbers, steps, operations, members, elements and/or groups thereof. and does not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements and/or groups.

The present invention relates to an industrial cable that has high heat resistance, high flexibility, and high flammability and does not cause blooming, comprising 30 to 40% by weight of ethylene propylene diene monomer (EPDM) without any crosslinking agent and 30 to 50% by weight of ethylene vinyl acetate resin. It is characterized in that it contains 50 to 78 parts by weight of a flame retardant, 1 to 5 parts by weight of a crosslinker, and 1 to 5 parts by weight of an antioxidant based on 100 parts by weight of the base resin consisting of 20 to 40 weight percent of polyolefin elastomer.

The base resin according to the present invention is preferably composed of 30 to 40% by weight of ethylene propylene diene monomer (EPDM), 30 to 50% by weight of ethylene vinyl acetate resin, and 20 to 40% by weight of polyolefin elastomer.

The ethylene propylene diene monomer (EPDM) is one in which no crosslinking agent is added, and is well suited to extrusion characteristics. Considering other physical properties, the Mooney Viscosity is preferably in the range of 60 to 80.

This ethylene propylene diene monomer is preferably contained in an amount of 30 to 40% by weight in the total base resin. If the content is less than 30% by weight, hardness increases and flexibility decreases, and if it exceeds 40% by weight, extrusion processability is reduced. It is not good and is undesirable because there are problems that may affect the occurrence of blooming.

In addition, the ethylene vinyl acetate resin contained in the base resin has a vinyl acetate content of 40 to 70% by weight. If the vinyl acetate content is less than 40% by weight, hardness increases and flexibility decreases, and if the vinyl acetate content is less than 40% by weight, the hardness increases and flexibility decreases. If it is exceeded, it is undesirable because the physical and electrical properties (volume resistance) deteriorate and the appearance becomes uneven.

This ethylene vinyl acetate resin is preferably contained in 30 to 50% by weight of the total base resin. If it is less than 30% by weight, the exterior surface is not smooth, and if it exceeds 50% by weight, physical and electrical properties are deteriorated. It is undesirable.

The base resin of the present invention contains 20 to 40% by weight of polyolefin elastomer. If it is less than 20% by weight of the total base resin, the physical properties are poorer, and if it exceeds 40% by weight, there are problems with heat resistance and extrusion processability, so it is preferable. can't do it

The industrial cable according to the present invention contains 50 to 78 parts by weight of a flame retardant, 1 to 5 parts by weight of a crosslinking agent, and 1 to 5 parts by weight of an antioxidant based on 100 parts by weight of the base resin.

The flame retardant may be used alone or in combination of aluminum hydroxide (Al(OH) ₃ , S-ATH) with a silane-coated surface and magnesium hydroxide (Mg(OH) ₃ , S-MDH) with a silane-coated surface. It can be contained in 50 to 78 parts by weight based on 100 parts by weight of the base resin. It is preferable in terms of securing flame retardancy and maintaining physical properties when the flame retardant content is included in an amount of 50 to 78 parts by weight based on 100 parts by weight of the base resin. However, when using magnesium fatty acid flame retardant as the flame retardant, caution is required as blooming phenomenon may occur in the immersion test.

The crosslinking agent according to the present invention is triallyl isocyanurate (TAIC), triallyl cyanurate (TAC), trimethylolpropane trimethacrylate (TMPTMA), and trimethylolpropane. One or more types selected from triacrylate (Trimethylolpropane Triacrylate, TMPTA) can be used, and triallyl isocyanurate (TAIC) is most preferably used. In the case of the cross-linking agent, polyfunctional monomers can be preferably used in the cross-linking process using electron beams since they can proceed with the cross-linking reaction even at low electron beam intensity. For proper crosslinking, the crosslinking agent is preferably included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the base resin.

In addition, the antioxidant is one or more selected from phenol-based, phosphorus-based, amine-based, and triazole-based, and is preferably included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the base resin for an appropriate antioxidant role.

It is obvious to those skilled in the art that, in addition to the ingredients listed above, the industrial cable according to the present invention may additionally contain conventional additives such as crosslinking accelerators and lubricants included in conventional cable compositions, if necessary.

The manufacturing process of the industrial cable according to the present invention is described as follows.

First, preparing a composition containing each of the components listed above and first kneading it by kneading; extruding the first kneaded composition with an extruder and then cutting it to produce a pellet-shaped raw material; It can be manufactured by extruding a pellet-shaped raw material into a cable of an arbitrary set length using an extruder, and crosslinking the cable with an electron beam accelerator.

Hereinafter, preferred embodiments of the present invention will be described in detail. The following examples are only for illustrating the present invention, and should not be construed as limiting the scope of the present invention by these examples. In addition, although the examples below are exemplified using specific compounds, it is obvious to those skilled in the art that equivalent effects can be achieved even when equivalents thereof are used.

Examples 1 to 2, and Comparative Examples 1 to 5

The ingredients according to each composition according to the following Table 1 were placed in a kneader and first kneaded to prepare a uniformly mixed mixture. The first kneaded mixture was put into an extruder and extruded, and then the cooled extrudate was cut into a predetermined size to make a pellet-shaped raw material. The pellet-shaped raw material was extruded into a cable of an arbitrary set length using an electric wire extruder. Finally, each cable was cross-linked with an electron beam accelerator to obtain the final desired cable.

Content (parts by weight) Comparative example Example One 2 3 4 5 One 2 base resin EPDM ⁽¹⁾ 80 60 30 30 30 30 30 EVA
(VA content 10-30% by weight) - 20 45 - - - - EVA
(VA content 40-70% by weight) - - - 45 - 45 45 EVA
(VA content exceeds 70% by weight) - - - - 45 - - POE 15 20 25 25 25 25 25 silicone rubber 5 - - - - - - flame retardant S-ATH ⁽²⁾ - 50 75 50 75 50 75 S-MDH ⁽³⁾ 30 - - - - 25 - Fatty acid coated MDH - 30 - 25 - - - additive Antioxidants ⁽⁴⁾ 2 2 2 2 2 2 2 Investigation cross-linking system ⁽⁵⁾ 2 2 2 2 2 2 2 (main)
(1) EPDM: No cross-linking agent added with Mooney viscosity of 60
(2)S-ATH: Aluminum hydroxide with silane-coated surface
(3)S-MDH: Magnesium hydroxide with silane-coated surface
(4) Antioxidant: Phenol type
(5) Irradiation crosslinking agent: Triallyl isocyanurate (TAIC)

Experiment example

The physical properties of each cable manufactured according to the above examples and comparative examples were measured as follows, and the results are shown in Table 2 below.

1. General conditions

1.1 The standard laboratory conditions are a temperature of 23 ±2℃ and a relative humidity of 50 ±5%.

1.2 The test piece should be used 48 hours after manufacturing and left for more than 24 hours under standard laboratory conditions.

2. Specific gravity

Follow the method specified in ISO 1183, Method A, 23℃.

3. Room temperature properties

Tensile strength and elongation are tested according to the method of IEC 60811-501.

4. Hardness

Follow the method specified in ISO 868. Room temperature flexibility can be judged.

5. Heat resistance properties (tensile and elongation after aging)

Measure room temperature tensile strength and elongation according to IEC 60811-501. Tensile strength and elongation after testing are measured under aging conditions of 150℃*168HR, 175℃*240HR, and 180℃*168HR to determine tensile and elongation residuals, cracks, etc.

6. Oil resistance test (tensile and elongation after oil resistance)

Tensile strength and elongation are measured after immersion at 50℃ for 10 hours with 1 to 3 types of lubricants specified in KS M 2121 and oil specified in KS M 2613.

7. MI (Melt flow index): Extrusion processability

Measure the value representing the extruded amount (weight unit/time unit) by applying a pressure of 10Kg at 170℃.

8. LOI (oxygen index)

Follow the method specified in ISO 4589-2. (The test piece uses a heated compressed sheet.)

9. Flame retardant

9-1. Flame retardancy (material, compound)

Produce and test the shape of the test piece (length 80~150mm, width 6.5mm, thickness 3mm) according to KS M ISO 4589-2.

9-2. Flame retardant (cable)

(1) Take a 300mm long sample and support it horizontally on the flame retardant tester.

Adjust the length of the oxidizing salt to about 130 mm and the length of the reducing salt to about 35 mm. Apply the front end of the reducing salt below the center of the sample for 10 seconds, remove the flame, and measure the combustion time of the sample.

(2) The sample consists of cable test pieces of 3.5 m each, and the number of test pieces must be appropriate for the volume of 1.5 L/m of non-metallic material.

Each test piece is mounted in the test equipment of IEC 60332-3-10 and flame is applied for 20 minutes.

Ensure that the maximum degree of carbonization ratio measured in the sample does not exceed 2.5 m in height from the bottom edge.

10. Combustibility

Follow the method specified in MS300-08 (Standard Test Method - Combustibility of Interior Materials). (The test piece uses a heated compressed sheet.)

11. Heating deformation test

Heat the test piece to 120℃ using a heat deformation tester, apply a load of 9.8N for 1 hour, and measure the thickness of the test piece.

Heating strain: D = (t1 - t2) / t1

12. Cold resistance test

Cold resistance tester: It consists of a test piece tong and a striking device, and the hitting device rotates at a constant linear speed of 1.97 m/s to hit the test piece.

Test method: Insert the test piece into the tongs under the measurement temperature conditions, leave it for 3 minutes, and then hit it. All three pieces must not be destroyed. Low-temperature flexibility can be determined by measuring cold resistance.

13. Volume resistance

After heating the test piece in a 30℃ chamber for 1 hour, measure the volume resistance by applying 500V of direct current for 1 minute.

14. Smoke density test

Smoke density testing follows ASTM E662-21 test.

(1) Businesses with a high risk of damage to life and property require 200DS or less, and industrial or business-use businesses require 450DS or less.

15. Bending (flexibility) test (Cable)

The bending (flexibility) test follows IEC-60227-2 test.

(1) After bending 15,000 and 30,000 times, there must be no current interruption or short circuit between conductors, and the withstand voltage test must be passed.

16. Blooming test

Follows the whitening test according to ES91900-00.

(1) Immersion test: Check whether whitening occurs after immersion in 80℃ distilled water for 7 days

(2) Wet test: Check whether efflorescence occurs after being left in an environment of 80℃ and 95% humidity for 30 days.

(3) Dry test: Check whether whitening phenomenon occurs after being left in an environment of 80℃ and humidity of 10% or less for 30 days.

Properties Comparative example Example One 2 3 4 One 2 2 Specific gravity (g/㎤) 1.09 1.25 1.25 5 1.24 1.25 1.24 Room temperature tensile strength (kgf/㎠) 1.97 1.82 1.16 1.02 1.32 1.4 1.35 Room temperature elongation (%) 650 340 343 476 391 292 350 Hardness (Shore A) 61 70 80 70 70 70 70 Tensile residual rate after aging (%)
(175℃ x 240HR) 83 106 85 79 40 80 80 Kidney residual rate after aging (%)
(175℃ x 240HR) 84 96 65 60 50 68 75 Tensile residual rate after oil resistance (%)
(50℃ x 10HR) 95 88 90 89 97 94 96 Kidney residual rate after internal milk (%)
(50℃ x 10HR) 88 85 91 89 85 87 88 MI (170℃, 10KG) (g/10min) 0.5 0.7 2.3 2.3 2.3 2.3 3.1 LOI (%) 24 26 25 25 26 26 27 Flame retardancy test
(Extinguished within 10 seconds) FAIL PASS PASS PASS PASS PASS PASS Combustibility test (self-extinguishing) PASS PASS PASS PASS PASS PASS PASS Heating deformation test (%)
(120℃, 1HR, 9.8N) 5 5 7 6 5 5 5 Cold resistance test (℃) -60 -50 -60 -60 -60 -60 -60 Volume resistance (Ω x Cm) 5 x 10 ¹⁵ 2 x 10 ¹⁵ 5 x 10 ¹⁴ 9 x 10 ¹⁵ 1 x 10 ¹² 7.8 x 10 ¹⁵ 3 x 10 ¹⁵ Smoke density test (DS Max) 85 75 70 75 71 72 70 Flexibility (bending) test
(Withstand voltage test) PASS PASS FAIL PASS PASS PASS PASS Appearance condition Good Good Good Good error Good Good Blooming
test
(occurrence or not) left at room temperature O X X X X X X deflation
(80℃ x 30 days) △ X X X X X X Wet (80℃, humidity 95% x 30 days) O X X X X X X Immersion (80℃,
Tap water immersion x 7 days) O O X O X X X

Referring to the results in Table 2, Experimental Example 1 is a cable manufactured with the composition according to Patent Document 1 and has excellent flexibility and high heat resistance, but has poor flame retardancy and M.I. The value is 0.5, indicating that extrusion processability is not good and blooming phenomenon occurs (○).

In addition, in Comparative Example 2, which changed the combination of the base resin and used a combination of EVA and POE instead of reducing the EPDM content, and used fatty acid-coated MDH in addition to S-ATH according to the present invention as a flame retardant, M.I. The extrusion processability was improved to a value of 0.7, but whitening occurred in the blooming immersion test.

In the case of Comparative Example 3, as in the present invention, EPDM, EVA (VA content 10 to 30% by weight), and POE were included as the base resin, and the composition was changed so that the flame retardant was within the scope of the present invention, so the blooming phenomenon did not occur. and M.I. The value was 2.3, which showed good extrusion processability, but since EVA VA content (10-30% by weight) was lower than Examples 1 and 2 (40-70% by weight), hardness increased and flexibility was poor.

In the case of Comparative Example 4, extrusion processability and flexibility were good by changing the base resin combination as in Examples 1 and 2, but as a result of using fatty acid-coated MDH by changing the flame retardant combination, a blooming phenomenon occurred in the immersion test.

In the case of Comparative Example 5, as in the present invention, EPDM, EVA (VA content 70-80%), and POE were included as the base resin, and the composition was changed so that the flame retardant was within the scope of the present invention, so the blooming phenomenon did not occur. , M.I. The value was 2.3, which showed good extrusion processability, but the EVA VA content (over 70% by weight) was higher than Examples 1 and 2 (40 to 70% by weight), so the appearance was not good, and the electrical properties (volume resistance) and heat resistance were poor. You can see that it is not good.

From the above results, it was possible to solve the workability or blooming phenomenon depending on the composition of the base resin or the combination of flame retardants used when manufacturing the cable. In particular, EPDM was used at 30 to 40% by weight out of 100% by weight of the base resin, but the content was reduced. It was confirmed that the workability is good and blooming does not occur, and that the blooming phenomenon can be suppressed when the vinyl acetate content of ethylene vinyl acetate resin is used at 40 to 70% by weight.

Claims (5)

Ethylene vinyl acetate resin with a Mooney Viscosity of 60 to 80, 30 to 40% by weight of ethylene propylene diene monomer (EPDM) with no crosslinker added, and 40 to 70% by weight of vinyl acetate in the resin. For 100 parts by weight of base resin consisting of 50% by weight and 20 to 40% by weight of polyolefin elastomer:
50 to 78 parts by weight of a flame retardant selected from aluminum hydroxide with a silane-coated surface alone or a mixture of aluminum hydroxide with a silane-coated surface and magnesium hydroxide with a silane-coated surface,
1 to 5 parts by weight of phenolic antioxidant, and
An industrial cable characterized in that it consists of 1 to 5 parts by weight of a triallyl isocyanurate irradiation crosslinking agent.

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