KR101774448B1 - Sheath Material Composition Of Signal Cable For Railway Vehicles With High Performance Flame Retardant And High Flexibility - Google Patents

Abstract

The present invention relates to a sheath material composition for a railway vehicle cable excellent in flexibility and flame retardancy. Wherein the sheath material composition comprises a mixed resin in which 20 to 60% by weight of a thermoplastic polyester elastomer (TPEE) resin and 40 to 80% by weight of an ethylene vinyl acetate (EVA) resin are mixed as a base resin, 100 to 180 parts by weight of a flame retardant. The sheath formed from the sheath material composition according to the present invention has excellent flexibility and flame retardancy as well as excellent oil resistance and heat resistance.

Description

TECHNICAL FIELD [0001] The present invention relates to a sheath material composition of a signal cable for a railway car having excellent flame retardancy and flexibility,

The present invention relates to a sheath material composition of a signal cable for a railway car.

Signal cables for railway vehicles are used in very severe conditions compared with ordinary cables, so they must have excellent characteristics such as heat resistance and oil resistance, and should be able to maintain their characteristics for a long time under various climatic conditions such as high temperature and low temperature as well as rapid temperature change. In addition, fire safety such as low flammability as well as flammability must be essential for securing the safety of life, cargo and equipment and minimizing the loss when a railway vehicle fires.

Conventionally, a basic resin containing a halogen such as polyvinyl chloride, polychloroprene or polychlorinated polyethylene as a sheath material of a signal cable for a railway car was mainly used. However, such halogen-containing base resins have a disadvantage of not only a high toxicity index but also a poor thermal property at a high temperature.

To solve these problems, there has been proposed a method of using a halogen-free base resin and using a large amount of a metal hydroxide as a halogen-free flame retardant. However, such a large amount of the flame retardant causes a problem that the mechanical properties and the properties after heating at a high temperature are remarkably lowered. In addition, there is a disadvantage in that oil resistance to oils such as diesel oil and polar oil is lowered.

On the other hand, in order to improve the oil resistance, a polar resin having a high polar group content is used as a base resin, or a crystalline resin or an engineering plastic having melting points equal to or higher than the test conditions for oil resistance is used. However, resins having high melting and crystallization and polyester engineering plastics are not only very hard at room temperature but also have low flexibility, so that it is difficult to install them in a narrow space or a complicated structure.

In order to solve the above problems, the present invention provides a sheath material composition for a signal cable for a railway car excellent in flexibility and flame retardancy.

In order to achieve the above object, the sheath material composition of a signal cable for a railway car excellent in flexibility and flame retardancy of the present invention comprises 20 to 60 wt% of a thermoplastic polyester elastomer (TPEE) resin and 40 to 80 wt% of an ethylene vinyl acetate (EVA) % Of a base resin is used as a base resin, and 100 to 180 parts by weight of a flame retardant is contained relative to 100 parts by weight of the base resin.

The sheath prepared by using the sheath material composition of the signal cable for a railway car excellent in flexibility and flame retardancy of the present invention is not only excellent in flexibility and flame retardancy but also excellent in oil resistance and heat resistance. Therefore, the sheath material composition of a signal cable for a railway car excellent in flexibility and flame retardancy can be manufactured by using the sheath produced according to the present invention.

Hereinafter, the present invention will be described in detail.

The sheath material composition of a signal cable for a railway car excellent in flexibility and flame retardancy according to the present invention comprises a mixed resin in which 20 to 60% by weight of a thermoplastic polyester elastomer (TPEE) resin and 40 to 80% by weight of an ethylene vinyl acetate (EVA) And 100 to 180 parts by weight of a flame retardant based on 100 parts by weight of the base resin.

With respect to the content of the thermoplastic polyester elastomer (TPEE) resin in the base resin, when the content is less than 20% by weight, the oil resistance is lowered. When the content is more than 60% by weight, the flexibility or heat resistance is lowered But the manufacturing cost also increases.

With respect to the content of the ethylene vinyl acetate (EVA) resin in the base resin, when the content is less than 40% by weight, the flexibility is lowered and the filler loading property is lowered. When the content exceeds 80% by weight The oil resistance is lowered.

In the sheath material composition of the present invention, a thermoplastic polyester elastomer (TPEE) resin and an ethylene vinyl acetate (EVA) resin are used without using a polar resin, a crystalline resin, an engineering plastic, ) Resin is used. As a result, the sheath produced by the sheath material composition of the present invention has excellent flexibility and low toxicity index.

The thermoplastic polyester elastomer (TPEE) resin included in the base resin of the present invention has a flexural modulus at room temperature of 30 to 100 MPa, preferably 40 to 80 MPa. When the flexural modulus is less than 30 MPa, the heat resistance or oil resistance is decreased. When the flexural modulus is more than 100 MPa, the flexibility is poor.

The thermoplastic polyester elastomer (TPEE) resin has a content of dimethyl terephthalate (DMT) of 10 to 60%, preferably 20 to 40%. When the content of dimethyl terephthalate (DMT) is less than 10%, the heat resistance or oil resistance is lowered, and when it exceeds 60%, the flexibility is poor.

The ethylene vinyl acetate (EVA) resin contained in the base resin of the present invention has a flexural modulus at room temperature of 5 to 40 MPa, preferably 5 to 20 MPa. When the flexural modulus is less than 5 MPa, heat resistance or mechanical strength is lowered, and when it is more than 40 MPa, flexibility is decreased.

The ethylene vinyl acetate (EVA) resin has a content of vinyl acetate (VA) of 10 to 50%, preferably 20 to 35%. When the content of the vinyl acetate (VA) is less than 10%, flexibility is poor. When the content exceeds 50%, not only the production cost is increased but also oil resistance or heat resistance is deteriorated.

The flame retardant of the present invention has an average particle size of 0.5 to 6 micrometers. When the average particle size is less than 0.5 micrometer, the gravitational pulling force of the flame retardant is increased due to the increase of the gravitational pulling force as the specific surface area of the particles increases. When the average particle size is more than 6 micrometers, The surface area of the flame retardant occupying is reduced, and the flame retardancy may be lowered.

As the flame retardant of the present invention, a metal hydroxide or zinc borate, ammonium molybdate, phosphorus flame retardant, etc., which are surface-treated with silane or fatty acid, may be used alone or in combination of two or more thereof. When a non-surface-treated flame retardant is used, the compatibility with the base resin is poor and the flame retardant is aggregated, resulting in a decrease in flexibility.

As the silane, vinylsilane, aminosilane and the like can be used.

As the metal hydroxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide, hydrotalcite, hydro-magneite and the like can be used, and the phosphorus-based flame retardant can be used.

The content of the flame retardant is 100 to 180 parts by weight, preferably 120 to 160 parts by weight, based on 100 parts by weight of the base resin. When the content is less than 100 parts by weight, the flame retardancy of the sheath deteriorates. When the content exceeds 180 parts by weight, the mechanical properties of the sheath deteriorate.

The sheath prepared using the sheath material composition of the present invention can be used in the manufacture of a signal cable for a railway vehicle excellent in flexibility and flame retardancy.

[Example]

Hereinafter, the present invention will be described more specifically by way of examples. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims and their equivalents. It should not be construed as an intention to limit the scope to example.

In order to investigate the performance change of the cis material composition of the signal cable for a railway car excellent in flexibility and flame retardancy according to the characteristics of the present invention, the cis material compositions of Examples and Comparative Examples were prepared with the composition of the base resin shown in Table 1 below. The sheath material composition was composed of 155 parts by weight of a flame retardant based on 100 parts by weight of the base resin, and a mixed resin obtained by mixing a thermoplastic polyester elastomer (TPEE) resin and an ethylene vinyl acetate (EVA) resin as the base resin was used.

Base resin Thermoplastic polyester elastomer resin
(weight%) Ethylene vinyl acetate resin
(weight%) Example 1 55 45 Example 2 20 80 Example 3 40 60 Example 4 60 40 Comparative Example 1 10 90 Comparative Example 2 90 10 Comparative Example 3 80 20 Comparative Example 4 70 30 Comparative Example 5 15 85

[Description of Components Used in Table 1]

* Thermoplastic polyester elastomer resin: flexural modulus 62 Mpa, dimethyl terephthalate content 33%

* Ethylene vinyl acetate resin: flexural modulus 10 Mpa, vinyl acetate content 33%

* Flame retardant: metal hydroxide surface treated with vinylsilane (H5A from Albright), particle size 0.65 ~ 0.95 ㎛

Measurement and evaluation of physical properties

i) A sheath was prepared using the sheath material composition according to the above Examples (1 to 4) and Comparative Examples (1 to 5), and the signal cable including the sheath was produced by a usual method, Oil resistance, heat resistance, and flame retardancy were tested using the specimens obtained by stripping and / or ii) pellets of the above-described sheath material composition, and compression-molded into sheet form, as examples and comparative examples, Respectively. The brief experimental conditions are as follows.

㉠ Flexibility

Flexibility was determined by the flexibility test of the specimen (ASTM D790). Flexural modulus was obtained at a point where a specimen of 3.2 mm × 12.7 mm × 125 mm was subjected to a load and 5% deformation of the specimen length occurred. The flexural modulus should be less than 1500 MPa.

㉡ Oil resistance

The oil resistance was measured according to the oil resistance test (IRM903) of the test piece. The specimen was taken not less than 600 mm and bent in U to make about 10 times the diameter of the magnet. After 168 hours of precipitation in diesel at 70 ° C, the specimens were removed and the percentage of extension was measured according to EN 60811-2-1. The oil retention rate should be not less than 70%.

㉢ Heat resistance

The heat resistance was measured according to the heat resistance test of the specimen (IEC 60811-1-1). The specimens were allowed to stand at 120 ° C for 168 hours, and then the elongation percentage was measured. Heat resistance The elongation percentage shall be not less than 75%.

㉣ Flammability

The flame retardancy was measured by the flame retardancy test (IEC60332-1) of the specimen. The flame retardancy measurement method is as follows. The flame should be applied to the specimen at a 45-degree angle for 60 seconds and the flame removed. The total burned length should be no more than 540 mm above the spark point.

Flexibility (MPa) Oil Resistance Elongation Ratio (%) Heat Resistance Elongation Ratio (%) Flammability Example 1 940 103 98 pass Example 2 340 72 102 pass Example 3 630 78 99 pass Example 4 978 100 85 pass Comparative Example 1 103 6.4 103 pass Comparative Example 2 1690 100 45 pass Comparative Example 3 1403 103 66 pass Comparative Example 4 1148 102 72 pass Comparative Example 5 146 9 93 pass

As summarized in Table 2, the specimens of Examples 1 to 4 satisfied the criteria in terms of flexibility, oil resistance and heat resistance, and passed the flammability test.

The specimens of Comparative Examples 1 and 5 did not satisfy the criterion for oil resistance. This is because the base resins of Comparative Examples 1 and 5 were composed of an insufficient amount of thermoplastic polyester elastomer resin and an excessive content of ethylene vinyl acetate resin, which were outside the range defined in the present invention.

In addition, the specimen of Comparative Example 2 did not satisfy the standard value in flexibility and heat resistance, and the specimens of Comparative Examples 3 and 4 did not satisfy the standard value in heat resistance. This is because the base resins of Comparative Examples 2 to 4 were composed of an excessive amount of the thermoplastic polyester elastomer resin and an excessively small amount of the ethylene vinyl acetate resin outside the range defined in the present invention.

From these results, it can be seen that the sheath made of the sheath material composition of the signal cable for a railway car excellent in flexibility and flame retardancy of the present invention and the power cable having the sheath material composition are excellent in flexibility and flame retardancy as well as satisfactory in oil resistance and heat resistance Able to know. These results were obtained by using a thermoplastic polyester elastomer (TPEE) resin having an optimum flexural modulus and a mixed resin obtained by mixing ethylene vinyl acetate (EVA) at an optimum ratio as a base resin, and obtaining an optimum average particle size Because of the use of a cis-material composition comprising a surface-treated flame retardant.

As described above, the optimal embodiments of the present invention have been disclosed. Although specific terms have been employed in the specification to include those embodiments, it will be understood that they have been used only for the purpose of describing the invention to those of ordinary skill in the art and are intended to limit the scope of the invention as defined in the claims Or not.

Claims (8)

A thermoplastic polyester elastomer (TPEE) resin having a flexural modulus at room temperature of 30 to 100 MPa and a content of dimethyl terephthalate (DMT) of 10 to 60% and a flexural modulus at room temperature of 5 to 40 MPa And 40 to 80% by weight of an ethylene vinyl acetate (EVA) resin having a content of vinyl acetate (VA) of 10 to 50% is used as a base resin,
With respect to 100 parts by weight of the base resin,
At least one flame retardant selected from the group consisting of metal hydroxide, zinc borate, ammonium molybdate and phosphorus flame retardant having an average particle size of 0.5 to 6 micrometers and surface treated with silane or fatty acid, And 180 parts by weight of a flame retardant. delete delete delete delete delete delete The signal cable for a railway car according to claim 1, comprising a sheath layer formed of a sheath material composition of a signal cable for a railway car excellent in flexibility and flame retardancy.