KR20040085783A - flame retardant thermoplastic composition for cable sheath having high performance of mechanical properties and long term heat stability and the cable using thereit - Google Patents

Abstract

PURPOSE: Provided is a composition for a highly fire resistant thermoplastic cable sheath material, which has excellent fire resistance, low fuming characteristics, excellent mechanical properties and long-term heat resistance. CONSTITUTION: The composition for a cable sheath material comprises: 100 parts by weight of a mixed polymer resin including ethylene copolymer having a melt index of 0.05 to 2 and a polyethylene resin to which a polar group is introduced; 80-200 parts weight of a hydrated metal compound; 0.1-5 parts by weight of a lubricant and a processing aid; 0.1-5 parts by weight of an antioxidant; and 1-10 parts by weight of an organic flame retardant. The composition is used for a sheath layer(6) in a cable.

Description

Flame retardant thermoplastic composition for cable sheath having high performance of mechanical properties and long term heat stability and the cable using thereit

The present invention relates to a high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long term heat resistance and a cable using the same.

In the past, the interest and development of flame retardancy of general ship cables have been insignificant, but recently, the difficulties of cable in response to the need to minimize the protection and loss of life and equipment in the event of fires in offshore structures and passenger ships used in isolated areas. The demand for softening is expanding.

The thermal stability at high temperatures and IEC 332-3 Cat. In order to secure high flame retardancy of class A, a thermosetting material in which a halogen compound such as bromine or a combustion lamp is added or crosslinked with a halogen-free non-halogen flame retardant sheath material was used as the bedding body and the sheath body.

The halogen-containing flame retardant material is still in IEC 332-3 Cat. Although it is widely used as an insulating material that satisfies class A, there is a disadvantage of being regulated by generating toxic gases that are harmful to the human body and cause corrosion of equipment, and in the case of thermosetting materials, there is a disadvantage of incombustibility.

In order to solve the problems of the halogen flame retardant material and to improve the flame retardant properties and low flame retardant properties, while using a conventional thermoplastic material, a variety of metal hydroxides and flame retardant auxiliaries, and also using crosslinked flame retardant materials or crosslinking In addition to the method, ethylene copolymers having a low polymer content were mixed with polyethylene having high melting temperature.

Metal hydroxide is added to the thermoplastic flame retardant material in place of the halogen-based flame retardant material, and the combustion is suppressed by the endothermic effect of dehydration during the combustion process to impart flame retardancy to the polymer composite resin and also during the combustion process. Since there is no emission of toxic gases such as halogens, there is an advantage in that low smoke characteristics are excellent.

Recently, huntite and magnesium carbonate may be used as a material to replace the metal hydroxide, which may exert not only an endothermic effect but also suppress combustion of the high-powder material while undergoing various pyrolysis behaviors.

In addition, a phosphorus-based flame retardant or the like may be used as a flame retardant aid in the thermoplastic flame retardant material, which is excellent in flame retardancy, thereby increasing the flame retardancy of the material.

In the case of crosslinked flame retardant materials, the drip characteristics during combustion are improved, and a solidified carbonized layer is formed during combustion, and thus, excellent flame retardant characteristics and low smoke characteristics are observed. Not only is it small, but also has excellent mechanical properties after heating, showing thermally stable properties.

On the other hand, a method in which polyethylene having a high melting temperature, for example, linear low density polyethylene, medium density polyethylene, or high density polyethylene, is mixed with an ethylene copolymer having a low polymer content is used to ensure thermal stability. It is used as flame retardant material which satisfies low thermal deformation and post-heating characteristics against stress

The above-mentioned conventional techniques are IEC 332-3 Cat. In addition to satisfying the class A, it was intended to satisfy both the electrical characteristics and the low smoke characteristics.

However, in order to increase the flame retardancy, by filling a large amount of inorganic flame retardant and auxiliary flame retardant into the polymer resin, the extrusion processability is poor, and mechanical properties such as room temperature elongation rate and post-heating property are deteriorated. Moreover, phosphorus flame retardant, red, polyphosphate In order to secure flame retardancy by applying a special flame retardant aid, such as may be in conflict with the low smoke characteristics.

In addition, the cross-linking method satisfies flame retardant properties, drip properties during combustion, and long-term thermal stability, but requires a double process and equipment for cable manufacture, and has a problem in that manufacturing costs are also high.

In addition to the crosslinking method, a method of mixing a resin having a high melting temperature with an ethylene copolymer having a low polymer content decreases as the melting temperature increases, and the copolymer determines the filling properties of a large amount of additives. Therefore, only a limited amount of flame retardant can be filled in the end, so it is difficult to expect an improvement in flame retardancy.

In addition, since the use of crystalline polymers having a high melting temperature, the flame retardant material becomes very hard, and thus there is a disadvantage that it is difficult to lay the cable.

Therefore, the present invention has been made to solve the above problems,

It is an object of the present invention to provide a highly flame retardant thermoplastic cable sheath material composition having excellent flame retardancy, low smoke characteristics, and excellent mechanical properties and long-term heat resistance at the same time, and a cable using the same.

An object of the present invention described above is 80 to 200 parts by weight of a hydrated metal compound, lubricant and processing aid 0.1 with respect to 100 parts by weight of a mixed polymer resin of an ethylene copolymer having a melt index of 0.05 to 2 and a polyethylene resin having a polar group introduced therein. It is achieved by a high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long term heat resistance consisting of from 5 parts by weight to 5 parts by weight, 0.1 to 5 parts by weight of antioxidant and 1 to 10 parts by weight of organic flame retardant.

In addition, the ethylene copolymer is ethylene vinyl acetate (EVA, Ethylene Vinyl Acetate), ethylene ethyl acrylate (EEA, Ethylene Ethyl Acrylate), ethylene butyl acrylate (EBA, Ethylene Buthyl Acrylate) and ethylene methyl acrylate (EMA, Ethylene Methyl Acrylate) is preferably any one, the content of the copolymer is preferably 12 to 30 parts by weight, more preferably contained in 40 to 95 parts by weight of 100 parts by weight of the mixed polymer resin.

The polyethylene having the polar group introduced therein is preferably a polyethylene polymer resin grafted with maleic anhydride or glycidyl methacrylate, wherein the graft ratio is preferably 0.1 to 5 parts by weight, and the melt index is linear to 0.1 to 5 Low density polyethylene (LLDPE), low density polyethylene (LDPE), medium density polyethylene (MDPE) and high density polyethylene (HDPE) are preferable, and it is more preferable to include 5 to 60 weight part of 100 weight part of mixed polymer resins.

And the metal hydride compound is preferably at least two or more selected from the group consisting of surface-treated or untreated aluminum hydroxide, huntite and magnesium hydrosides, and includes all of aluminum hydroxide, futite and magnesium hydrosides. It is more preferable that 50-170 weight part of aluminum hydroxide is contained with respect to 100 weight part of mixed polymer resins, and it is more preferable that 30-150 weight part of huntite and magnesium hydroside are included.

The object of the present invention described above is achieved by a cable comprising the sheath body 6 composed of the sheath material composition described above.

1 is a schematic diagram showing a cable cross section to which the cable material is applied according to an embodiment of the present invention;

2 is a schematic diagram showing a cable cross section to which a cable material is applied according to another embodiment of the present invention.

* Short description of drawing symbols *

1: Conductor 2: Ethylene Propylene Rubber Insulator

3: polyethylene insulator 4: core assembly

5: knitted body 6: sheath

Hereinafter, a high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long term heat resistance according to the present invention will be described in detail.

The present invention uses a mixed polymer resin of an ethylene copolymer and a polyethylene having a polar group as a base resin in order to have both thermal stability at high temperatures, flame retardancy and low smoke characteristics, to improve the flame retardant properties and low smoke characteristics , Metal hydride compounds were used, organic flame retardants were used as flame retardant aids for suppressing smoke density, promoting solidification of char and curing of ash, and lubricants and processing aids were used to improve processability and dispersibility of inorganic flame retardants.

It is preferable that the ethylene copolymer has a melt index of 0.05 to 2, but when the melt index is less than 0.05, there is a problem that the load is high when processing due to high viscosity, and there is a problem that the compatibility decreases, and the melt index exceeds 2 In this case, there is a problem that the tensile strength at room temperature is lowered and the heat resistance is lowered, and in particular, the long-term thermal stability at high temperature is lowered.

As said ethylene copolymer, ethylene vinyl acetate, ethylene ethyl acrylate, ethylene butyl acrylate, and ethylene methyl acrylate are preferable, for example.

In the use of the ethylene copolymer, it is preferable to optimize the proportion of the copolymer for filling the flame retardant for improving the flame retardancy, it is preferable to use 12 parts by weight to 30 parts by weight of the copolymer.

If it is less than 12 parts by weight, it is difficult to obtain high flame retardancy and the kneading property between the resin and the hydrated metal compound is also lowered. And when it exceeds 30 weight part, mechanical properties fall.

It is preferable that content of an ethylene copolymer is 40 weight part-95 weight part with respect to 100 weight part of mixed polymer resins used as a base resin.

If it is less than 40 parts by weight, the flame retardancy is lowered and the elongation of the elongation is rapidly decreased in mechanical properties. And when it exceeds 95 parts by weight, after 6 hours of heating at 80 ℃ heat deformation properties are significantly reduced and the tensile strength value of the mechanical properties is lowered.

As the polyethylene in which the polar group is introduced, for example, linear low density polyethylene, low density polyethylene, medium density polyethylene, high density polyethylene, and 100 parts by weight of maleic anhydride or glycidyl methacrylate are grafted at 0.1 parts by weight to 5 parts by weight. Preference is given to using polyethylene.

When the graft ratio, that is, the content of maleic anhydride or glycidyl methacrylate is less than 0.1 part by weight, the kneading property with the ethylene copolymer is lowered, so that flame retardancy, low smokeability, and mechanical properties cannot be expected. Drops sharply.

The polyethylene in which the polar group is introduced is preferably applied from 5 parts by weight to 60 parts by weight based on 100 parts by weight of the mixed polymer resin.

If it is less than 5 parts by weight, it is not expected to improve the flame retardancy and low smoke, mechanical properties and thermal properties, and if it exceeds 60 parts by weight, the elongation and flame retardancy are deteriorated.

The melt index of the polyethylene in which the polar group is introduced is particularly preferable in the case of 0.1 to 5.

If it is less than 0.1, there is a problem that the load is high when processing due to the high viscosity, and if it is more than 5, there is a problem that the normal temperature tensile strength is lowered.

As the hydration metal compound, for example, a mixed polymer resin may be used by mixing any one or two or more of aluminum hydroxide, huntite and magnesium hydroside surface-treated or non-surface-treated with any one or two or more of fatty acids, silanes and polymers. It is preferable to use 80 to 200 parts by weight based on 100 parts by weight.

If it is less than 80 parts by weight, it is difficult to secure flame retardancy, and if it exceeds 200 parts by weight, workability and elongation are lowered.

In the case of using a mixture of aluminum hydroxide, humite and magnesium hydroside, it is preferable to use aluminum hydroxide in an amount of 50 parts by weight to 170 parts by weight based on 100 parts by weight of the mixed polymer resin.

If the amount is less than 50 parts by weight, the flame retardant synergistic effect and the solidification of the carbonized layer cannot be obtained. The amount of the hydrous aluminum is not significantly increased. do.

In addition, it is preferable to use a fumedite and hydromagnesite mixed flame retardant from 30 parts by weight to 150 parts by weight based on 100 parts by weight of the mixed polymer resin.

Less than 30 parts by weight of the increase in flame retardant effect by the mixing of the hydration compound is not effective, there is no effect of lowering the smoke concentration.

It is preferable to use low molecular weight polyethylene, a silicone type processing aid, stearic acid, etc. as said lubricant and a processing aid, for example, and it is preferable to use 0.1 weight part-5 weight part with respect to 100 weight part of mixed polymer resins.

If the amount of the lubricant is less than 0.1 part by weight, improvement in workability such as a decrease in viscosity of the material cannot be expected. If it exceeds 10 parts by weight, flame retardancy and tensile strength are lowered.

The antioxidant is used to increase the continuous use temperature in terms of heat resistance, for example, phenol (phenol), hindered phenol (hindered phenol), thioester (thioester), amine (amine), etc. It is preferable to use 0.1 weight part-5 weight part of inhibitors with respect to 100 weight part of mixed polymer resins.

If it is less than 0.1 part by weight, there is no effect of addition, and if it exceeds 5 parts by weight, mechanical properties and the like are lowered.

Although the said organic flame retardant is especially preferable to use a silicone type organic flame retardant, it is preferable to use 1 weight part-10 weight part with respect to 100 weight part of mixed polymer resins.

When the content of the organic flame retardant is less than 1 part by weight, the effect of suppressing the smoke density and promoting the solidification of the char cannot be expected. When the content of the organic flame retardant exceeds 10 parts by weight, the flame retardancy and the smoke suppression effect are also lowered.

1 is a schematic diagram showing a cable cross section to which a cable material is applied according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing a cable cross section to which a cable material is applied according to another embodiment of the present invention.

As shown in FIGS. 1 and 2, the cable according to the present invention using the sheath material composition has a conductor 1 composed of a collection of helically twisted pairs or a collection of unit conductors, and is formed inside the inside. This is insulated by an ethylene propylene rubber insulator 2 as shown in FIG. 1 or a polyethylene insulator 3 as shown in FIG. 2 to form a circular core assembly 4.

A bedding layer (not shown) is formed over the core assembly 4, and as shown in FIG. 2, a braid 5 is formed thereon to support the structure simultaneously with waterproofing thereon, and the sheath material composition thereon. The sheath body 6 is formed.

Hereinafter, the present invention will be described in more detail by explaining preferred embodiments of the present invention. However, the present invention is not limited to the following examples, and various forms of embodiments can be implemented within the scope of the appended claims, and the following examples are only common to those skilled in the art to complete the present disclosure. It is intended to facilitate the implementation of the invention to those with knowledge.

EXAMPLE

In the present embodiment, by varying the component and composition ratio, after kneading in an open roll was molded for 10 minutes at 170 ℃, to prepare a test specimen.

Table 1 shows each component and composition ratio of these Examples.

Example One 2 3 4 5 Ethylene Vinyl Acetate1 60 60 - - - Ethylene Vinyl Acetate2 - - 60 - - Ethylene Ethyl Acrylate1 - - - 60 - Ethylene Ethyl Acrylate2 - - - - 60 Polar group introduction polyethylene 40 40 40 40 40 Sodium hydroxide 120 150 150 150 150 Huntite and Hydromagnesite 50 50 50 50 50 Silicone Organic Flame Retardant 5 5 5 5 5 Lubricant 2 2 2 2 2 Antioxidant 0.2 0.2 0.2 0.2 0.2

* Ethylene vinyl acetate 1: 18 parts by weight of vinyl acetate, MI-0.7

* Ethylene vinyl acetate 2: 17 parts by weight of vinyl acetate, MI-0.8

Ethylene ethyl acrylate 1: 12 parts by weight of ethyl acrylate, MI-1.5

Ethylene ethyl acrylate 2: 25 parts by weight of ethyl acrylate, MI-2

[Comparative Example]

In the present Comparative Example, by varying the components and composition ratio, after kneading in an open roll was molded for 10 minutes at 170 ℃, to prepare a test specimen.

Table 2 shows each component and the composition ratio in this comparative example.

Comparative example One 2 3 Ethylene Vinyl Acetate3 60 60 - Ethylene Vinyl Acetate4 - - 60 Polar group introduction polyethylene 40 40 40 Aluminum hydroxide 150 180 150 Huntite and Hydromagnesite 50 - 50 Silicone Organic Flame Retardant 5 5 5 Lubricant 2 2 2 Antioxidant 0.2 0.2 0.2

* Ethylene vinyl acetate 3: 18 parts by weight of vinyl acetate, MI-2.5

Ethylene vinyl acetate 4: 33 parts by weight of vinyl acetate, MI-1.5

Combustion length, smokeability, heating deformation, winding heating, tensile strength, elongation rate and oxygen index of the above Examples and Comparative Examples were evaluated as follows.

First, the combustion length measurement for flame retardancy is measured after applying 400,000 calories of 70,000 Btu / hr in accordance with the IEC 332-3 cat.A flame retardant test standard. The combustion length of the cable should be less than 2.44.

Next, the measurement of smoke is tested in the state of finished cable according to IEC 1034, and transmittance should satisfy 60% or more.

Next, heating deformation was evaluated according to IEC 60092-359 SHFI standard.

Next, the coil heating is evaluated according to the IEC 60092-359 SHFI standard.

Next, room temperature tensile strength and room temperature elongation are measured by tensile strength and elongation in accordance with ASTM D 638.

Finally, the oxygen index was tested according to ASTM D 2863.

Table 3 shows the results of measuring the measured combustion length, smoke properties, heating deformation, winding heating, room temperature tensile strength, room temperature elongation and oxygen index.

Test Items Example Comparative example One 2 3 4 5 One 2 3 Combustion length (m) 1.5 1.2 1.3 1.4 1.5 1.5 1.8 1.1 Room temperature tensile strength (kgf / mm ² ) 1.27 1.26 1.37 1.42 1.39 1.02 1.19 0.98 Room Temperature Elongation (%) 202 184 179 150 165 186 183 179 Heating strain (%) 18 12 15 10 13 55 46 100 Winding heating Pass Pass Pass Pass Pass Fail Fail Fail Smoke Pass Pass Pass Pass Pass Pass Pass Pass Oxygen index 34 38 36 33 34 34 27 35

As shown in Table 1, the present embodiments are based on ethylene vinyl acetate or ethylene ethyl acrylate having a melt index of 0.05 to 2, and a polyethylene having a polar group introduced therein, and thus aluminum hydroxide, hunite and hydromagnesite. Is used as a flame retardant, a silicon-based organic compound is used as a smoke density inhibitor and a flame retardant aid, and other lubricants and antioxidants are applied.

In this embodiment, the combustion length is less than 1.5m combustion characteristics, excellent oxygen index of 34 to 38 can be obtained, the heat deformation is less than 20% and showed very good thermal stability at the temperature of 80 ℃. . In addition, the results of the wound heating test also showed good results.

On the other hand, when ethylene vinyl acetate (MI-2.5) having a high melt index was used as in Comparative Examples 1 and 2, satisfactory physical properties were not exhibited at room temperature tensile strength (1.02, 1.19) and winding heating (Fail, Fail). .

In the case of Comparative Example 2, in contrast to Comparative Example 1, only aluminum hydroxide was used alone without using huntite and magnesium hydroside, but did not exhibit satisfactory physical properties in Fail and Oxygen Index (27). .

In the case of Comparative Example 3, ethylene vinyl acetate having a melt index of 1.5 was applied, but a high vinyl acetate content (33 parts by weight) was applied. In this case, although the combustion length (1.1) was low, the tensile strength and winding heating at room temperature were low. Did not exhibit satisfactory physical properties.

In Comparative Examples 1 to 3, satisfactory high temperature heat resistance could not be obtained as a result of the heat deformation test.

Therefore, it can be concluded that the thermoplastic non-halogen flame-retardant polymer resin composition according to the present embodiment has excellent flame retardancy and low smoke resistance, and at the same time, has a long-term thermal stability and mechanical properties at high temperatures, unlike the comparative examples.

Therefore, the cables manufactured using the same can be said to be suitable for use for signal and power supply purposes in marine structures such as ships or drilling vessels such as passenger ships.

The sheath material composition according to the present invention is a non-toxic non-halogen flame retardant material, which satisfies the flame retardancy of IEC 332-3 cat. And mechanical properties achieve excellent effects. The cable according to the invention using the sheath material composition also achieves an effect suitable for use for signal and power supply purposes, especially in marine structures such as ships or drilling vessels such as passenger ships.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications or variations without departing from the spirit and scope of the invention. Accordingly, the appended claims will cover such modifications and variations as fall within the spirit of the invention.

Claims (12)

100 parts by weight of a mixed polymer resin of an ethylene copolymer having a melt index of 0.05 to 2 and a polyethylene resin having a polar group introduced therein; 80 to 200 parts by weight of a metal hydride compound; 0.1 to 5 parts by weight of lubricant and processing aid; 0.1 to 5 parts by weight of antioxidant; And 1 to 10 parts by weight of an organic flame retardant; a high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance. The method of claim 1, wherein the ethylene copolymer, A high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that any one of ethylene vinyl acetate, ethylene ethyl acrylate, ethylene butyl acrylate and ethylene methyl acrylate. The method of claim 1, wherein the ethylene copolymer, A high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that the content of the copolymer is 12 to 30 parts by weight based on 100 parts by weight of the ethylene copolymer. The method of claim 1, wherein the ethylene copolymer, High flame-retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that it comprises 40 to 95 parts by weight of 100 parts by weight of the mixed polymer resin. The method of claim 1, wherein the polyethylene in which the polar group is introduced, A high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long term heat resistance characterized by grafting maleic anhydride or glycidyl methacrylate. The method of claim 5, wherein the polyethylene in which the polar group is introduced, High flame-retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that the graft ratio is 0.1 to 5 parts by weight with respect to 100 parts by weight of polyethylene. The method of claim 1, wherein the polyethylene in which the polar group is introduced, A high flame retardant thermoplastic cable sheath material composition having any one of linear low density polyethylene, low density polyethylene, medium density polyethylene, and high density polyethylene, having a melt index of 0.1 to 5. The method of claim 1, wherein the polyethylene in which the polar group is introduced, High flame-retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that it comprises 5 to 60 parts by weight of 100 parts by weight of the mixed polymer resin. The method of claim 1, wherein the metal hydride compound, A high flame retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that it is composed of at least two selected from the group consisting of surface treated or untreated aluminum hydroxide, humite and magnesium hydrosides. The method of claim 9, wherein the metal hydride compound, High flame-retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that 50 to 170 parts by weight of aluminum hydroxide, based on 100 parts by weight of the mixed polymer resin. The method of claim 9, wherein the metal hydride compound, High flame-retardant thermoplastic cable sheath material composition having excellent mechanical properties and long-term heat resistance, characterized in that 30 to 150 parts by weight of huntite and magnesium hydroside are included with respect to 100 parts by weight of the mixed polymer resin. A cable comprising a sheath body (6) constituted by the sheath material composition according to any one of the preceding claims.