KR101532330B1 - Resin composition for producing nisulation material of a cable - Google Patents

Abstract

The present invention relates to a resin composition for producing a cable insulation material. The present invention relates to a base resin comprising a mixture of 20 to 60% by weight of polyethylene and 40 to 80% by weight of an ethylene-propylene-diene copolymer; 90 to 130 parts by weight of a filler based on 100 parts by weight of the base resin; And 3 to 9 parts by weight of a peroxide-based crosslinking agent based on 100 parts by weight of the base resin, wherein the filler is selected from the group consisting of clay and magnesium silicate surface-treated with a vinyl group. INDUSTRIAL APPLICABILITY According to the present invention, it is possible to manufacture an insulation material of a cable having an improved initial modulus and improved high temperature heat distortion characteristics. Therefore, even if the cable is disposed in a twisted environment due to vertical or horizontal warpage or the like depending on the use purpose and characteristics of the cable, it has a strong deformation characteristic and can reduce the conductor breakage rate.

Modulus, stress, torsion, high temperature deformation characteristics, moving cable

Description

Technical Field [0001] The present invention relates to a resin composition for producing a cable insulation material,

The present invention relates to a resin composition for producing a cable insulation material, and more particularly, to a resin composition comprising a base resin, a filler, and a crosslinking agent blended so as to improve initial modulus and heat distortion characteristics at high temperatures.

Polyethylene, which has been mainly used as insulation material for conventional cables, is a typical nonpolar molecular sieve composed of only carbon-carbon bonds and carbon-hydrogen bonds. It has neither ionic polarization nor dipole polarization in the electric field. . Therefore, it is known that polyethylene has excellent insulation property and excellent stability against oxidation as compared with polyolefin.

However, since polyethylene has no polar group in its interior, it has a disadvantage that it is not highly resistant to oil and is poor in elongation and flexibility due to its high crystallinity. In addition, since polyethylene alone can not meet required physical properties such as heating, smoke density and oxygen index, various additives for supplementing other functions have been used. However, the use of such an additive is difficult due to the high crystallinity of polyethylene And other side effects due to the use of the additive are also generated, and it is a reality that preparation of the material for manufacturing the cable insulation material is not easy.

Particularly, the high crystallinity of polyethylene has caused the flexibility to deteriorate. Therefore, when polyethylene is applied to a moving cable that is not fixed during use, it may result in insulation breakage at frequent twisting and bending, and the extension ratio of the cable And thus a high stress is applied to the conductor in the range of the moving space of the conductor, thereby adversely affecting the conductor breakage rate.

Various efforts have been made to solve the above-mentioned problems, and the present invention has been made based on this technical background.

A problem to be solved by the present invention is to prevent the conductor from being broken due to repeated stress applied to the cable conductor when the cable is installed in a vertical, horizontal or warped state and is placed in an environment where it is twisted by physical or natural forces The cable insulation is solved the problem of the continuous thermal deformation caused by the current flow and the initial modulus is improved and the high temperature heat distortion property is improved The present invention provides a resin composition for manufacturing a cable insulation material.

A resin composition for manufacturing a cable insulation material provided as a solution to the problem of the present invention comprises a base resin comprising 20 to 60% by weight of polyethylene and 40 to 80% by weight of an ethylene propylene diene copolymer; 90 to 130 parts by weight of a filler based on 100 parts by weight of the base resin; And 3 to 9 parts by weight of a peroxide-based crosslinking agent based on 100 parts by weight of the base resin, wherein the filler is selected from the group consisting of clay and magnesium silicate surface-treated with a vinyl group.

The polyethylene preferably has a density of 0.89 to 0.93 g / cm 3, a melt index (MI) of 0.1 g / 10 min to 30 g / 10 min, and a weight average molecular weight of 5,000 to 25,000.

It is preferable that the ethylene propylene diene copolymer contains an ethylene content of 60 to 80% by weight.

The peroxide cross-linking agent is preferably a dicumyl peroxide or 1,1-di- (tert-butylperoxy) -3,5,5-trimethyl cyclohexane.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to manufacture an insulation material of a cable having an improved initial modulus and improved high temperature heat distortion characteristics. Therefore, even if the cable is disposed in a twisted environment due to vertical or horizontal warpage or the like depending on the use purpose and characteristics of the cable, it has a strong deformation characteristic and can reduce the conductor breakage rate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings in order to facilitate understanding of the present invention. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the invention are provided to more fully describe the present invention to those skilled in the art.

A resin composition for manufacturing a cable insulation material provided as a solution to the problem of the present invention comprises a base resin comprising 20 to 60% by weight of polyethylene and 40 to 80% by weight of an ethylene propylene diene copolymer; 90 to 130 parts by weight of a filler based on 100 parts by weight of the base resin; And 3 to 9 parts by weight of a peroxide-based crosslinking agent based on 100 parts by weight of the base resin, wherein the filler is selected from the group consisting of clay and magnesium silicate surface-treated with a vinyl group.

With respect to the numerical range with respect to the content of polyethylene contained in the base resin, when it is less than the lower limit, the modulus and the room temperature value are undesirably lowered. If the upper limit is exceeded, the loading property with the filler is lowered It is undesirable because it adversely affects cable flexibility. On the other hand, with respect to the numerical value range with respect to the content of the ethylene propylene diene copolymer contained in the base resin, if it is below the lower limit, the flexibility of the cable is deteriorated and the high temperature thermal heat distortion property is deteriorated. If the upper limit is exceeded, Value is undesirably low.

With respect to the numerical range with respect to the content of the above-mentioned peroxide cross-linking agent, if it is below the lower limit, the degree of crosslinking is low and the heating property and the room temperature characteristic are insufficient. If the upper limit is exceeded, the possibility of crosslinking in a short time increases, The initial crosslinking can proceed, and the amount of the crosslinking agent not participating in crosslinking and the addition amount thereof may deteriorate the physical properties of the resin composition, which is not preferable.

With respect to the numerical range of the content of the clay surface-treated with the vinyl group selected by the filler, if it is below the lower limit, the crosslinking property is lowered, which is undesirable, and if it exceeds the upper limit, the tensile strength is lowered.

With respect to the numerical range with respect to the content of magnesium silicate selected as the filler, if it is below the lower limit, the tear strength is lowered, and if it exceeds the upper limit, the physical properties at room temperature, that is, tensile strength and elongation, .

The polyethylene preferably has a density of 0.89 to 0.93 g / cm 3, a melt index (MI) of 0.1 g / 10 min to 30 g / 10 min, and a weight average molecular weight of 5,000 to 25,000.

With respect to the numerical range with respect to the density of the polyethylene, if it is below the lower limit, the heat resistance deteriorates due to the decrease in the degree of crosslinking. If the upper limit is exceeded, the premature decomposition and premature crosslinking of the crosslinking agent during chemical crosslinking Which is undesirable. With respect to the numerical range with respect to the melt index of polyethylene, if it is below the lower limit, molding can not proceed easily during extrusion processing, and desired mechanical properties are not secured, which is undesirable. If the upper limit is exceeded, It is not preferable because a difference in processing temperature is caused between the ethylene propylene diene copolymer in which the behavior characteristics are lowered and the melt tension is increased and mixed together, thereby making the processing process difficult. With respect to the numerical range with respect to the weight average molecular weight of the polyethylene, if it is below the lower limit, the basic physical properties of the room temperature tensile strength and elongation can not be satisfied and if it exceeds the upper limit, the melt index is low, And loadability is poor.

The ethylene propylene diene copolymer preferably has an ethylene content of 60 to 80% by weight and a Mooney viscosity (ML1 + 4, 125 캜) of 20 to 40.

Regarding the numerical range with respect to the ethylene content, if it is below the lower limit, the thermal heat distortion property is lowered, and if it exceeds the upper limit, the flexibility and elongation property are not preferable. With respect to the numerical range for the pattern viscosity, if the lower limit is not reached, the moldability is lowered, which makes it difficult to perform the extrusion work. If the upper limit is exceeded, there is a problem in initial crosslinking and difficulty in extrusion .

The peroxide cross-linking agent is preferably a dicumyl peroxide or 1,1-di- (tert-butylperoxy) -3,5,5-trimethyl cyclohexane.

On the other hand, the resin composition for cable insulation material provided by the present invention having the above-mentioned composition may further contain an antioxidant, a lubricant, a processing aid, and the like. Preferably, the antioxidant may be a phenol-based or amine-based antioxidant. If necessary, it may be mixed with other types of antioxidants such as phosphate, imidazole, and sulfur . In the case of a lubricant, it is added in an amount of 1 to 2 parts by weight based on 100 parts by weight of the base resin, and in the case of a lubricant, It is preferably added in an amount of 10 to 15 parts by weight based on 100 parts by weight of the resin.

After preparing the resin compositions of Examples and Comparative Examples having the compositions set forth in the following Table 1, kneading was performed at 110 ° C in an open roll to measure various physical properties, and 250-300 kgf / cm 2 was added at 170 ° C for 20 minutes After crosslinking, test specimens suitable for each test item were prepared, and the test results are shown in Table 2 below.

division Examples (1 to 5) Comparative Examples (1 to 7) One 2 3 4 5 One 2 3 4 5 6 7 Resin a 20 20 30 40 40 - 100 - 20 30 30 30 Resin b 80 80 70 60 60 100 - 20 - 70 70 70 Resin c - - - - - - - 80 80 - - - Filler a 100 70 70 100 120 100 100 100 70 80 150 - Filler b - 30 30 - - - - - 30 - - - Filler c - - - - - - - - - - - 100 Cross-linking agent 3 3 3 3 3 3 3 3 3 3 3 3 Antioxidant 2 2 2 2 2 2 2 2 2 2 2 2 Processing aid 10 10 10 10 10 10 10 10 10 10 10 10 Lubricant 2 2 2 2 2 2 2 2 2 2 2 2

In Table 1, resin a is a low density polyethylene having a density of 0.92 g / cm 3 and a melt index of 20 g / 10 min. The resin b is an ethylene propylene diene copolymer having an ethylene content of 70% by weight, ML (1 + 4) 25 and the resin c is an ethylene propylene diene copolymer having an ethylene content of 57.5% by weight, and ML (1 + 4) 125 ° C has a value of 40. [ The filler a is a magnesium silicate having a particle size of 7 탆, the filler b is a silicate aluminum clay surface-treated with a vinyl group, and the filler c indicates calcium carbonate having a particle diameter of 1.5 탆. In Table 1, dicumyl peroxide was used as a crosslinking agent, IRGANOX 1010, a phenolic primary antioxidant, was used as an antioxidant, and low molecular weight wax was used as a lubricant.

The tensile strength at room temperature and elongation at break are measured at a rate of 250 mm / min in accordance with IEC 60811-1-1. The tensile strength and tensile strength at room temperature shall be 8.5 N / mm2 or more and elongation of 200% or more, respectively, in accordance with IEC 60092-351. The 10% insulation modulus was compared with the modulus by using the strain - stress curve as the reference point considering the insulation maximum strain when twisting the cable. The heat-induced deformation was measured in accordance with IEC 60811-3-1. For specimens having a thickness of 2.0 ± 0.2 mm, a width of 15 mm, and a length of 30 mm, the specimen was placed in a blade jig at 150 ° C. and a load of 1 kg was applied for 60 minutes The change in specimen thickness before and after was measured and calculated. The reference value for excellent thermal heating deformation was 10%. The fracture rate of the conductor at the time of twisting was calculated as a percentage of the total number of breaks after confirming the breakage number of the internal conductor after performing a total of 10,000 times at 180 ° / m fh ± 3 turns. The acceptance criterion related to this is 5%.

division Examples (1 to 5) Comparative Examples (1 to 7) One 2 3 4 5 One 2 3 4 5 6 7 Tensile strength (N / mm 2) 1.2 1.3 1.5 1.8 2.0 0.7 2.0 1.0 1.4 1.3 1.7 1.7 Elongation (%) 490 460 560 624 580 850 180 520 480 410 300 200 10% modulus 330 360 380 430 450 210 550 290 410 220 400 380 Thermal heat distortion (%) 8.2 6 6.5 8.62 9.2 13 21 14 10.8 8 13 16 Conductor breakage rate (%) 4.1 3.5 3.8 2.4 2.3 38 29 20 3.1 42 3.8 3.0

According to the test results shown in Table 2 above, Examples (1-5) were judged to be good in all physical properties evaluation.

In Comparative Example 1, tensile strength at room temperature and initial modulus value were below the reference value due to insufficient crystallinity of the resin, and it was found that the heat-induced deformation characteristics exceeded the reference value of 10%. In Comparative Example 2, the elongation percentage was lower than the standard value due to excessive crystallization and excessive amount of heavy stabilizers, and the heat-shrinkage strain showed a high value due to the melting point of the low-density polyethylene lower than the test temperature, and the fracture percentage And the stresses applied to the conductors are weak, resulting in poor results. Comparative Example 3 is a case in which only ethylene propylene diene copolymer is mixed with only ethylene having a proper ethylene content and not using polyethylene, which does not satisfy the 10% modulus and thermal heating deformation standards, and conductor fracture The rate did not meet the criterion and the result was undesirable. In Comparative Example 4, the minimum content of polyethylene and the maximum content of the ethylene-propylene-diene copolymer were blended in such a manner that the ethylene content of the ethylene-propylene-diene copolymer was smaller than the reference value, It can be confirmed that the reference value is not satisfied.

On the other hand, in Comparative Example 5, in order to examine the effect of magnesium silicate, when 80 parts by weight, which is less than the proper amount, was used, the tensile strength and elongation at room temperature were lowered compared with the case where the optimum content was used. % Modulus decreased and a high conductor breakage rate was observed. In Comparative Example 6, when 150 parts by weight of magnesium silicate was used in an amount exceeding the optimum amount, the tensile strength at room temperature was improved, but the elongation was decreased and the elasticity of the material was lowered, It can be seen that the heat deformation characteristics are below the standard. Comparative Example 7 shows that the filler different from the one used in the present invention is used, the elongation percentage is lowered, and the thermal heat distortion property is lower than the standard.

Best modes of carrying out the invention have been disclosed. Although specific terms are employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims.

Claims (4)

A base resin comprising 20 to 60% by weight of polyethylene, 20 to 40 of Mooney viscosity (ML1 + 4, 125 DEG C) and 40 to 80% by weight of an ethylene propylene diene copolymer containing 60 to 80% by weight of ethylene ; 90 to 130 parts by weight of a filler based on 100 parts by weight of the base resin; And And 3 to 9 parts by weight of a peroxide-based crosslinking agent based on 100 parts by weight of the base resin, Wherein the filler is selected from the group consisting of clay and magnesium silicate surface-treated with a vinyl group or a mixture thereof. The method according to claim 1, Wherein the polyethylene has a density of 0.89 to 0.93 g / cm 3 and a melt index (MI) of 0.1 g / 10 min to 30 g / 10 min and a weight average molecular weight of 5,000 to 25,000. Resin composition for manufacturing. delete 3. The method according to claim 1 or 2, Wherein the peroxide cross-linking agent is Dicumyl peroxide or 1,1-di- (tert-butylperoxy) -3,5,5-trimethyl cyclohexane. Resin composition for manufacturing cable insulation material.