KR20180090632A - Composition for sheath of cable comprising thermoplastic polyurethane resin and cable having a sheath layer formed from the same - Google Patents

Abstract

The present invention relates to a composition for a sheath of a cable comprising a thermoplastic polyurethane resin and to a cable having a sheath layer formed therefrom. Specifically, the present invention relates to the composition for the sheath of the cable which is excellent in mechanical properties such as excellent abrasion resistance, durability and the like and elasticity, and to improve the fire-retardant properties, a fire-retardant agent is added, and thus even when the melt viscosity is increased, the extrusion load during extrusion can be effectively lowered to improve the extrusion properties and the productivity by the extrusion properties, and the deterioration of a base resin can be suppressed and the continuity of an extrusion process is ensured, and present invention also relates to the cable having the sheath layer formed therefrom.

Description

TECHNICAL FIELD The present invention relates to a composition for a cable sheath comprising a thermoplastic polyurethane resin and a cable having a sheath layer formed therefrom,

The present invention relates to a cable sheath composition comprising a thermoplastic polyurethane resin and to a cable having a sheath layer formed therefrom. More specifically, the present invention relates to a flame retardant composition which is excellent in mechanical properties such as excellent abrasion resistance and durability and elasticity, and which is improved in flame retardancy by effectively reducing the extrusion load during extrusion even when the melt viscosity increases, To a cable sheath composition capable of suppressing deterioration of a base resin and securing continuity and uniformity of an extrusion process and a cable having a sheath layer formed therefrom.

Recently, with the spread of factory automation (FA) facilities in the industrial field, there is an increasing demand for FA cables used in facilities that perform repetitive movement such as factory automation facilities, for example, transportation devices and robots Such FA cables are required to have good mechanical strength such as abrasion resistance and durability, and excellent reliability such as excellent elasticity and flame retardancy depending on the use environment.

Generally, thermoplastic polyurethane resins have excellent mechanical properties such as abrasion resistance and durability and elasticity in non-crosslinked form, and besides thermosetting resins such as crosslinked rubber, which is generally used elastic material, processes such as injection and extrusion are used And is used in various industrial fields such as automobile, electric wire, pneumatic hose, and shoes.

However, since thermoplastic polyurethane resin is weakly flame retardant and is decomposed into low molecular substances during burning and dripping, it is inevitable to use it in fields requiring excellent flame retardant properties such as FA cable. On the other hand, there is a method of adding a flame retardant to overcome the weak flame retardancy of the thermoplastic polyurethane resin, but this increases the melt viscosity of the thermoplastic polyurethane resin, thereby increasing the extrusion load during the extrusion for manufacturing the FA cable, .

The thermoplastic polyurethane resin is a polymer of an ester group or an ether group and a polyol group and is very vulnerable to hydrolysis. As described above, due to the increased extrusion load due to the addition of the flame retardant, There is a problem that the friction between the die and the die increases and the time for staying on the die increases, hydrolyzing and deteriorating some thermoplastic polyurethane resins, and the continuity of the extrusion process is hindered.

Therefore, even when the melt viscosity is increased by adding a flame retardant agent for improving the mechanical properties and elasticity such as excellent abrasion resistance and durability and the flame retardancy is improved, the extrusion load and the productivity can be improved by effectively lowering the extrusion load during extrusion, A FA cable including a composition for cable sheath and a sheath layer formed therefrom that can suppress the deterioration of the base resin and ensure continuity of the extrusion process is in desperate need.

An object of the present invention is to provide a cable sheath composition which is excellent in mechanical properties such as abrasion resistance and durability, elasticity, flame retardancy and the like.

It is another object of the present invention to provide a composition for cable sheath which can improve extrusion performance and productivity by effectively reducing the extrusion load during extrusion despite the increase of melt viscosity by adding a flame retardant to improve flame retardancy.

Further, it is an object of the present invention to provide a composition for cable sheath which can suppress the deterioration of the base resin as the retention time in the extrusion die increases due to the increased extrusion load, and ensure continuity and uniformity of the extrusion process .

In order to solve the above problems,

A composition for cable sheath, which comprises a thermoplastic polyurethane resin, a flame retardant and a lubricant, wherein the lubricant has a solubility coefficient of the thermoplastic polyurethane resin with a solubility coefficient of 占 5.

Herein, the thermoplastic polyurethane resin has a solubility coefficient of 20 to 24, and a composition for cable sheath is provided.

Also, the thermoplastic polyurethane resin is prepared by polymerization of an ester or an ether group and a polyol.

The present invention also provides a cable sheath composition, wherein the thermoplastic polyurethane resin is produced by polymerization of an ester group and a polyol, and the lubricant is an ester-based lubricant.

On the other hand, the composition for cable sheath is characterized in that the thermoplastic polyurethane resin is produced by polymerization of an ether group and a polyol, and the lubricant is an ether-based lubricant.

Further, the thermoplastic polyurethane resin has a Shore A hardness of 80 to 95 and a melting point (Tm) of 150 to 170 ° C.

Also, the composition for cable sheath is characterized in that the content of the lubricant is 0.5 to 1.5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane resin.

The flame retardant may include 20 to 30 parts by weight of a phosphorus-based flame retardant and 20 to 30 parts by weight of a melamine-based flame retardant based on 100 parts by weight of the thermoplastic polyurethane resin.

Here, the phosphorus flame retardant is an organometallic phosphinate flame retardant, and the melamine flame retardant is melamine cyanurate.

The present invention also provides a composition for cable sheath, which further comprises at least one additive selected from the group consisting of moisture release, antioxidant and talc.

There is provided a cable having a sheath layer formed from the composition for cable sheath.

The composition for cable sheath according to the present invention exhibits excellent effects such as mechanical properties such as abrasion resistance and durability, elasticity and flame retardancy by the addition of the thermoplastic polyurethane resin and the flame retardant.

In addition, the composition for cable sheath according to the present invention can improve the extrusion performance, productivity, and the like by effectively reducing the extrusion load in spite of the increased melt viscosity by the addition of a specific activator to the flame retardant addition, It is possible to ensure continuity and uniformity of the film.

Fig. 1 is a graph showing the extrudability and extrusion uniformity in extruding from the compositions for cable sheaths of Examples and Comparative Examples, respectively.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the constitutions described in the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the technical ideas of the present invention. Therefore, various equivalents which can be substituted at the time of application It should be understood that variations can be made.

The composition for a cable sheath according to the present invention comprises a thermoplastic polyurethane resin (TPU) as a base resin, and further comprises a flame retardant for improving the flame retardancy, a thermoplastic polyurethane resin for improving the extrusion load Specific lubricants, other additives, and the like.

The thermoplastic polyurethane resin (TPU) as the base resin is excellent in mechanical properties such as tensile strength, elongation and abrasion resistance, and excellent in bending property and oil resistance. Generally, in the case of thermoplastic polyurethane resin, the properties of the thermoplastic polyurethane resin vary depending on the composition ratio of the soft part and the hard part. The thermoplastic polyurethane resin applicable to the base resin of the cable sheath composition is ester or ether, May be a thermoplastic polyurethane resin which is formed by polymerization of a polyol with a group and thus the soft part is an ester type polyol or a soft part is an ether type polyol.

The thermoplastic polyurethane resin may have a melting point (Tm) of 150 to 170 占 폚, a Shore A hardness of 80 to 95, and a Shore A hardness of the thermoplastic polyurethane resin of less than 80, , While it may be lower than the strength standard. If it is more than 95, the hardness of the cable sheath layer may be excessive, and the bending property of the cable may be greatly deteriorated.

The flame retardant is preferably a flame retardant such as an organometallic phosphinate flame retardant or the like and a melamine cyanurate such as, for example, an organometallic phosphinate flame retardant or the like, in order to facilitate the formation of char in a fire in consideration of the processing temperature of the thermoplastic polyurethane resin as a base resin Based flame retardant such as a flame retardant and the like may be used in combination, and 20 to 30 parts by weight of a phosphorus-based flame retardant and 20 to 30 parts by weight of a melamine-based flame retardant may be added based on 100 parts by weight of the base resin.

In the cable sheath composition of the present invention, the melt viscosity increases with the addition of the flame retardant, and thus the extrusion load during extrusion is increased. As a result, the extrudability of the sheath layer and the productivity of the cable are greatly reduced, As the load increases, the time for which the composition stays in the extrusion die increases, the thermoplastic polyurethane resin which is susceptible to hydrolysis may be partially deteriorated.

Therefore, the composition for cable sheath of the present invention may further include a specific activator to increase the melt viscosity by the addition of the above-mentioned flame retardant and consequently to prevent an increase in extrusion load upon extrusion, The present inventors have completed the present invention by experimentally confirming that the effect of suppressing the increase of the extrusion load is remarkably improved when a lubricant having a solubility coefficient similar to that of the thermoplastic polyurethane resin is employed.

If the solubility coefficients of the thermoplastic polyurethane resin and the lubricant added thereto are similar, the compatibility between the thermoplastic polyurethane resin and the lubricant increases, thereby maximizing the effect of the lubricant, that is, the effect of suppressing the increase in the extrusion load. Specifically, the solubility coefficient of the thermoplastic polyurethane resin is about 20 to 24, and the solubility coefficient of the lubricant may be a solubility coefficient of the thermoplastic polyurethane resin of 5 or about 15 to 29. [

In addition, the lubricant having a solubility coefficient of the thermoplastic polyurethane resin of a solubility coefficient of ± 5 may be an ester-based activator when the thermoplastic polyurethane resin is an ester-based polyol type formed by polymerization of an ester group and a polyol , And an ether-based polyol type in which the thermoplastic polyurethane resin is formed by polymerization of an ether group and a polyol.

Here, the content of the lubricant may be 0.5 to 1.5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane resin as the base resin. If the content of the lubricant is less than 0.5 parts by weight, the effect of suppressing the increase in the extrusion load by the lubricant is insignificant. If the amount of the lubricant is more than 1.5 parts by weight, the mechanical properties such as abrasion resistance, hardness and strength of the cable sheath layer . Meanwhile, the composition for cable sheath according to the present invention may further include antioxidants, talc, and the like as other additives.

The composition for a cable sheath of the present invention contains the above-described thermoplastic polyurethane resin as a base resin and has mechanical strength and elasticity such as excellent abrasion resistance, strength and hardness, and also contains a specific flame retardant as described above And the melt viscosity is increased by the addition of the flame retardant and the extrusion load during extrusion is increased. The problem is solved by adding a specific amount of a specific lubricant, and as a result, the extrudability of the sheath layer, the productivity of the cable And the continuity and uniformity of the extrusion process can be ensured while suppressing deterioration of the base resin.

On the other hand, the present invention relates to a cable including a sheath layer formed from the composition for cable sheath described above, for example, an FA cable.

[Example]

1. Manufacturing Example

Compositions for cable sheath were prepared from the constituent components and contents shown in Table 1 below, and sheath specimens and cable specimens were prepared therefrom.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Suzy 100 Flame Retardant 1 25 25 25 25 35 25 25 15 Flame Retardant 2 25 25 25 25 25 35 15 25 Loot 1 0.5 0.5 0.5 0.5 0.5 Loot 2 0.5 Loot 3 0.5 Other 4 4 4 4 4 4 4 4

- Resin: thermoplastic polyurethane resin (Shore A hardness: 80 to 95; melting point (Tm): 150 to 170 ° C)

Flame retardant 1: Phosphorous expansion flame retardant (nitrogen content: 19 to 23% by weight; phosphorus content: 16 to 20% by weight)

Flame Retardant 2: melamine cyanurate (purity: 99.5%; residual cyanic acid: not more than 0.2 wt%; residual melamine: not more than 0.3 wt%, average particle size (D ₅₀ ): 1 to 4 μm)

- Lubricant 1: ester-based wax

- Lubricant 2: Silicone lubricant

- Lubricant 3: Fluorine-based lubricant

- Other: I release moisture, antioxidant, talc

2. Property evaluation

1) Room temperature property evaluation

Tensile strength, tear strength and elongation were measured for each of the sheath layer specimens of the examples and comparative examples at an evaluation rate of 250 mm / min according to standard EN 50363-10-2. Tensile strength shall not be less than 2.8 kgf / ㎟, tear strength shall be not less than 50 N / m and elongation shall be not less than 300%.

2) Oxygen index evaluation

The Limited Oxygen Index (LOI) was measured for each of the sheath layer specimens of the Examples and Comparative Examples according to Specification ASTM D2863. The limit oxygen index should be at least 28%.

3) Evaluation of flame retardancy

The flame resistance of each of the sheath layer specimens of Examples and Comparative Examples was evaluated according to Specification IEC 60332.

4) Extrusion characteristics evaluation

Extrusion performance and uniformity of extrusion were evaluated by measuring the extrusion amount over a period of time using Hakke mini single extruder. The hourly extrusion volume should be at least 2.8 kg / h and the extrusion volume by section should be uniform.

The physical property evaluation results are shown in Table 2 and FIG. 1 below.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 The tensile strength
(kgf / mm2) 4.25 4.19 4.28 4.08 4.51 4.42 3.7 3.6 Elongation (%) 368 357 342 372 284 252 432 426 Tear strength (N / m) 58 54 52 53 38 32 57 56 LOI (%) 28.5 29 28.5 29 32 28 28 24 Extrusion rate per hour
(kg / h) 3.21 3.17 1.98 2.76 2.82 2.79 3.47 3.41 Extrusion uniformity Great Bad Bad Good Good Good Great Great Flammability pass pass pass pass pass pass fail fail

As shown in Table 2 and FIG. 1, the composition of Example 1 according to the present invention was excellent in mechanical properties such as tensile strength, elongation, tear strength and the like of the specimens prepared therefrom, and was also excellent in evaluation of LOI and flame retardancy , Extrudability and extrusion uniformity.

On the other hand, the compositions of Comparative Examples 1 and 2 including a silicone lubricant and a fluorine-containing lubricant which are not an ester-based lubricant were found to be inferior in terms of the amount of extrusion and / or extrusion uniformity per hour due to the poor compatibility between the lubricant and the base resin, It was confirmed that the composition of Comparative Example 3 which did not contain a lubricant had an extrudability which was evaluated as an amount of extrusion per hour as being below the standard value and that the compositions of Comparative Examples 4 and 5 in which the flame retardant was excessively added had mechanical properties such as elongation and tear strength It was confirmed that the composition of Comparative Examples 6 and 7, in which the flame retardant was insufficiently added, had an inferior flame retardancy.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

Claims (11)

As a composition for cable sheath,
A thermoplastic polyurethane resin, a flame retardant, and a lubricant,
Wherein the lubricant has a solubility coefficient of a coefficient of solubility of 占 5 of the thermoplastic polyurethane resin. The method according to claim 1,
Wherein the thermoplastic polyurethane resin has a solubility coefficient of 20 to 24, 3. The method of claim 2,
Wherein the thermoplastic polyurethane resin is produced by polymerization of an ester or an ether group with a polyol. The method of claim 3,
Wherein the thermoplastic polyurethane resin is prepared by polymerization of an ester group and a polyol, and the lubricant is an ester-based lubricant. The method of claim 3,
Wherein the thermoplastic polyurethane resin is prepared by polymerization of an ether group and a polyol, and the lubricant is an ether-based lubricant. 6. The method according to any one of claims 1 to 5,
Wherein the thermoplastic polyurethane resin has a Shore A hardness of 80 to 95 and a melting point (Tm) of 150 to 170 占 폚. 6. The method according to any one of claims 1 to 5,
Wherein the content of the lubricant is 0.5 to 1.5 parts by weight based on 100 parts by weight of the thermoplastic polyurethane resin. 6. The method according to any one of claims 1 to 5,
Wherein the flame retardant comprises 20 to 30 parts by weight of a phosphorus-based flame retardant and 20 to 30 parts by weight of a melamine-based flame retardant based on 100 parts by weight of the thermoplastic polyurethane resin. 9. The method of claim 8,
Wherein the phosphorus flame retardant is an organometallic phosphinate flame retardant and the melamine flame retardant is melamine cyanurate. 6. The method according to any one of claims 1 to 5,
Wherein the composition further comprises at least one additive selected from the group consisting of moisture release, antioxidant and talc. A cable having a sheath layer formed from the composition for cable sheath of any one of claims 1 to 5.

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