Thermoplastic polypropylene cable shielding material and preparation method thereof

Abstract

The invention discloses a thermoplastic polypropylene cable shielding material and a preparation method thereof. The thermoplastic polypropylene cable shielding material comprises the following raw materials in percentage by weight: 35-75% of polypropylene, 2-25% of a toughening agent, 0.5-2% of a toughening compatibilizer, 20-40% of oxidized carbon black, 0.1-1% of an antioxidant and 0.1-1% of a lubricant. According to the invention, the problems of poor carbon black dispersion effect and poor low temperature resistance of the thermoplastic polypropylene cable shielding material are solved at the same time, and the application of the polypropylene cable shielding material in a complex environment, especially a low-temperature environment, can be met.

Description

Technical Field

[0001] The invention relates to a cable shielding material, in particular to a thermoplastic polypropylene cable shielding material and a preparation method thereof. Background Art

[0002] Electricity is an important infrastructure for the development of the national economy, and cables are essential materials for the application of electricity. The most commonly used insulating material for power cables is cross-linked polyethylene (XLPE). However, due to the increasing demand for cables, the high energy consumption and difficulty in recycling of XLPE cables have attracted more and more attention. As sustainable development continues to gain popularity, thermoplastic polypropylene has gradually become a research focus with its excellent electrical and heat resistance. It has the characteristics of no need for cross-linking in the production process, simple process, energy consumption can be reduced by more than 50%, and can be recycled and reused. At present, some companies have developed polypropylene insulation materials, but there are few reports on the matching recyclable shielding materials. To achieve the widespread application of thermoplastic polypropylene cables, it is necessary to develop polypropylene semi-conductive shielding materials.

[0003] Generally speaking, cable shielding materials need to add a lot of carbon black to achieve a semi-conductive effect, but carbon black and polypropylene have poor compatibility, which makes it difficult to evenly disperse carbon black in polypropylene, resulting in poor semi-conductive effect. In addition, due to the complex application environment of cables, the poor low-temperature impact of polypropylene also limits the application of polypropylene shielding materials, especially in high-cold and low-temperature places.

[0004] Patent CN118027597A improves the compatibility of carbon black with the matrix and the dispersibility of carbon black by using a compatibilizer, but requires the use of a carboxyl-modified toughening agent, which increases the cost and fails to solve the problem of poor low-temperature resistance of polypropylene shielding materials.

[0005] Patent CN113549276A prepares a polypropylene shielding material with low temperature resistance by introducing polyethylene or its derivatives and thermoplastic elastomer, but fails to solve the problem of poor carbon black dispersion effect of the polypropylene shielding material.

[0006] Therefore, it is necessary to find new solutions to solve the above problems so as to facilitate the application of polypropylene shielding materials in complex environments. Summary of the invention

[0007] In order to solve the above technical problems, the present invention proposes a thermoplastic polypropylene cable shielding material and a preparation method thereof. The present invention introduces a specific toughening and compatibilizing agent containing epoxidized functional groups into the polypropylene cable shielding material, which can, on the one hand, undergo a grafting reaction with oxidized carbon black, and on the other hand, improve the compatibility with polypropylene, thereby promoting the uniform dispersion of carbon black in the polypropylene matrix and improving the semi-conductive performance; at the same time, the thermoplastic polypropylene cable shielding material provided by the present invention has excellent low-temperature impact performance.

[0008] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0009] A thermoplastic polypropylene cable shielding material, comprising the following raw materials in percentage by weight:

[0010] Polypropylene 35-75%, preferably 45-60%;

[0011] Toughener 2-25%, preferably 10-20%;

[0012] Toughening and compatibilizing agent 0.5-2%, preferably 1.0-1.5%;

[0013] Oxidized carbon black 20-40%, preferably 25-35%;

[0014] Antioxidant 0.1-1%, preferably 0.2-0.6%;

[0015] Lubricant 0.1-1%, preferably 0.2-0.5%.

[0016] As a preferred solution, the polypropylene is ethylene copolymerized polypropylene, and its melt index at 190°C and 2.16 kg is 0.5 to 15 g / 10 min, preferably 1 to 10 g / 10 min.

[0017] As a preferred embodiment, the toughening agent is one or more of ethylene-octene copolymer, ethylene-butene copolymer, and hydrogenated styrene-butadiene block copolymer (SEBS), preferably one or more of ethylene-octene copolymer, ethylene-butene copolymer, and hydrogenated styrene-butadiene block copolymer having a melt index ≤10g / 10min at 230°C and 2.16kg. More preferably, the melt index of the above toughening agent is 0.5-8g / 10min.

[0018] As a preferred embodiment, the toughening and compatibilizing agent is an epoxidized modified product of an unsaturated cyclic siloxane monomer, wherein the unsaturated cyclic siloxane monomer is preferably a methyl-containing unsaturated cyclic siloxane monomer, and more preferably one or more of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and pentamethylpentavinylcyclopentasiloxane; the selection of the above unsaturated cyclic siloxane monomers is beneficial to further improve the compatibility with the polypropylene system.

[0019] As a preferred embodiment, the oxidized carbon black is obtained by oxidizing conductive carbon black with nitric acid.

[0020] As a preferred embodiment, the antioxidant is selected from hindered phenol antioxidants and / or phosphite antioxidants, preferably one or two of antioxidants 1010 and 168;

[0021] Preferably, the lubricant is one or more of polypropylene wax and polyethylene wax.

[0022] The present invention also provides a method for preparing the thermoplastic polypropylene cable shielding material as described above, characterized in that polypropylene, a toughening agent, a toughening and compatibilizing agent, oxidized carbon black, an antioxidant, and a lubricant are mixed and melt-extruded to obtain the thermoplastic polypropylene cable shielding material;

[0023] Preferably, the raw materials are mixed using a high-speed mixer, and the mixing conditions are: temperature of 10 to 40°C, rotation speed of 50 to 400 rpm, preferably 100 to 300 rpm, and mixing time of 3 to 8 min, preferably 4 to 7 min;

[0024] Preferably, the melt extrusion adopts a reciprocating single screw extruder, and the operating conditions are: screw temperature 180-230° C., preferably 190-220° C., and rotation speed 150-600 rpm, preferably 200-500 rpm.

[0025] As a preferred embodiment, the preparation method of the toughening and compatibilizing agent is:

[0026] Under stirring conditions, unsaturated cyclic siloxane monomer and oxidant are mixed and heated for reaction; after the reaction is completed, the product is purified to obtain a toughening and compatibilizing agent;

[0027] Preferably, the oxidant is one or more of hydrogen peroxide, oxygen, perbenzoic acid, peracetic acid, m-chloroperbenzoic acid, trifluoroperacetic acid, peracetone, and potassium persulfate. The reaction solvent can be selectively added according to the type of the oxidant. For example, when the oxidant is hydrogen peroxide, no additional solvent is required. If it is a solid such as perbenzoic acid, some reaction-inert solvents such as dichloromethane need to be added. The amount of the oxidant can be generally adjusted.

[0028] Preferably, the oxidant is a 50-90% hydrogen peroxide solution, and its amount is 20-50% of the mass of the unsaturated cyclic siloxane monomer based on the mass of the solution.

[0029] Preferably, the heating reaction conditions are: first react at 20-50° C. for 4-8 h, then heat to 80-100° C. for 5-10 h.

[0030] As a preferred embodiment, the preparation method of the oxidized carbon black is:

[0031] Under stirring conditions, carbon black and concentrated nitric acid are mixed and reacted; after the reaction is completed, centrifugation is performed, washing is performed, and drying is performed to obtain oxidized carbon black;

[0032] Preferably, the mixed reaction conditions are: 80-120° C. for 5-10 h.

[0033] Preferably, the amount of concentrated nitric acid used is 5-10 times the mass of carbon black.

[0034] The invention solves the problems of poor carbon black dispersion effect and poor low temperature resistance of thermoplastic polypropylene cable shielding material, and can meet the application of polypropylene cable shielding material in complex environment, especially low temperature environment. DETAILED DESCRIPTION

[0035] The present invention is further described below by means of specific examples. The examples described in the present invention are only used to illustrate the present invention and do not limit the scope of the present invention.

[0036] The raw material information used in the examples and comparative examples is shown in Table 1:

[0037] Table 1. Main raw material information

[0038]

[0039]

[0040] The test method adopted by the present invention is as follows:

[0041] (1) Tensile strength and elongation at break test: refer to GB / T528-2009 for testing;

[0042] (2) Volume resistivity test (23°C and 90°C): Tested in accordance with IEC 62631-3-1:2016;

[0043] (3) -25℃ impact strength test: Tested in accordance with GB / T 5470:2008.

[0044] The equipment used in the present invention:

[0045] High-speed mixer: 120L pot-type high-speed mixer, Suzhou Songyuan Environmental Protection Technology Co., Ltd.;

[0046] Reciprocating single screw extruder: The reciprocating single screw extruder used is a product of Jiangsu Chengmeng Equipment Co., Ltd., model GWHS58-100.

[0047] [Example 1]

[0048] Prepare the raw materials of thermoplastic polypropylene cable shielding material according to the following weight percentages:

[0049] Polypropylene 3015, 55%,

[0050] Toughener G1657V, 15%,

[0051] Toughening and compatibilizing agent a, 1.2%,

[0052] Oxidized carbon black a, 28%,

[0053] Irganox1010 0.2%, Irganox168 0.2%,

[0054] Licocene PP6102 0.4%.

[0055] The toughening and compatibilizing agent a is prepared by reacting tetramethyltetravinylcyclotetrasiloxane and 70% hydrogen peroxide in a mass ratio of 1:0.3 at 30° C. for 5 h, then heating to 90° C. for 7 h, and then purifying.

[0056] The oxidized carbon black a is obtained by mixing conductive carbon black F500 and concentrated nitric acid in a mass ratio of 1:8, reacting at 100°C for 8 hours, centrifuging and washing.

[0057] The above raw materials were mixed in a high-speed mixer in proportion, mixed at a temperature of 30° C. and a rotation speed of 300 rpm for 6 minutes, and then the mixed raw materials were melt-extruded through a reciprocating single-screw extruder, wherein the screw temperature was 210° C. and the rotation speed was 400 rpm, to obtain a thermoplastic polypropylene cable shielding material.

[0058] [Example 2]

[0059] Prepare the raw materials of thermoplastic polypropylene cable shielding material according to the following weight percentages:

[0060] Polypropylene X1956A, 72.7%,

[0061] Toughener Engage8150, 5%,

[0062] Toughening and compatibilizing agent b, 2%,

[0063] Oxidized carbon black b, 20%,

[0064] Irganox1010 0.1%, Irganox168 0.1%,

[0065] SN-102, 0.1%.

[0066] The toughening and compatibilizing agent b is prepared by reacting 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane and 50% hydrogen peroxide in a mass ratio of 1:0.2 at 50° C. for 4 hours, heating to 80° C. for 10 hours, and then purifying.

[0067] The oxidized carbon black b is obtained by mixing conductive carbon black F900A and concentrated nitric acid in a mass ratio of 1:5, reacting at 120° C. for 5 h, centrifuging and washing.

[0068] The above raw materials were mixed in a high-speed mixer in proportion, mixed at a temperature of 10°C and a rotation speed of 400 rpm for 3 minutes, and then the mixed raw materials were melt-extruded through a reciprocating single-screw extruder, wherein the screw temperature was 180°C and the rotation speed was 150 rpm, to obtain a thermoplastic polypropylene cable shielding material.

[0069] [Example 3]

[0070] Prepare the raw materials of thermoplastic polypropylene cable shielding material according to the following weight percentages:

[0071] Polypropylene EPS30R, 38.2%,

[0072] Toughener Engage7467, 22%,

[0073] Toughening and compatibilizing agent c, 0.5%,

[0074] Oxidized carbon black c, 38%,

[0075] Irganox1010 0.2%, Irganox168 0.1%,

[0076] Licocene PP6102, 1%.

[0077] The toughening and compatibilizing agent c is prepared by reacting pentamethylpentavinylcyclopentasiloxane and 60% hydrogen peroxide in a mass ratio of 1:0.5 at 20° C. for 8 h, then heating to 100° C. for 9 h, and then purifying.

[0078] The oxidized carbon black c is obtained by mixing conductive carbon black F500 and concentrated nitric acid in a mass ratio of 1:10, reacting at 80°C for 10 hours, centrifuging and washing.

[0079] The above raw materials were mixed in a high-speed mixer in proportion, mixed at a temperature of 40° C. and a rotation speed of 80 rpm for 8 minutes, and then the mixed raw materials were melt-extruded through a reciprocating single-screw extruder, wherein the screw temperature was 230° C. and the rotation speed was 600 rpm, to obtain a thermoplastic polypropylene cable shielding material.

[0080] [Example 4]

[0081] Prepare the raw materials of thermoplastic polypropylene cable shielding material according to the following weight percentages:

[0082] Polypropylene SP179P, 60.6%,

[0083] Toughener G1657V, 11%,

[0084] Toughening and compatibilizing agent d, 1.5%,

[0085] Oxidized carbon black d, 26%,

[0086] Irganox1010 0.3%, Irganox168 0.3%,

[0087] SN-102, 0.3%.

[0088] The toughening and compatibilizing agent d is obtained by reacting tetramethyltetravinylcyclotetrasiloxane and 80% hydrogen peroxide in a mass ratio of 1:0.4 at 40°C for 6 hours, then heating to 90°C for 6 hours, and then purifying.

[0089] The oxidized carbon black d is obtained by mixing conductive carbon black F900A and concentrated nitric acid in a mass ratio of 1:6, reacting at 90°C for 9h, centrifuging and washing.

[0090] The above raw materials were mixed in a high-speed mixer in proportion, mixed at a temperature of 25° C. and a rotation speed of 150 rpm for 7 minutes, and then the mixed raw materials were melt-extruded through a reciprocating single-screw extruder, wherein the screw temperature was 190° C. and the rotation speed was 250 rpm, to obtain a thermoplastic polypropylene cable shielding material.

[0091] [Example 5]

[0092] Prepare the raw materials of thermoplastic polypropylene cable shielding material according to the following weight percentages:

[0093] Polypropylene YPJ-1215C, 45.2%,

[0094] Toughener Engage8150, 20%,

[0095] Toughening and compatibilizing agent e, 1%,

[0096] Oxidized carbon black e, 33%,

[0097] Irganox1010 0.1%, Irganox168 0.2%,

[0098] Licocene PP6102, 0.5%.

[0099] The toughening and compatibilizing agent e is obtained by reacting pentamethylpentavinylcyclopentasiloxane and 90% hydrogen peroxide in a mass ratio of 1:0.45 at 30° C. for 5 hours, then heating to 100° C. for 6 hours, and then purifying.

[0100] The oxidized carbon black e was obtained by mixing conductive carbon black F500 and concentrated nitric acid in a mass ratio of 1:9, reacting at 110°C for 7h, centrifuging and washing.

[0101] The above raw materials were mixed in a high-speed mixer in proportion, mixed at a temperature of 30° C. and a rotation speed of 300 rpm for 7 minutes, and then the mixed raw materials were melt-extruded through a reciprocating single-screw extruder, wherein the screw temperature was 220° C. and the rotation speed was 500 rpm, to obtain a thermoplastic polypropylene cable shielding material.

[0102] [Comparative Example 1]

[0103] A polypropylene cable shielding material was prepared in substantially the same manner as in Example 1, except that no toughening and compatibilizing agent a was added.

[0104] [Comparative Example 2]

[0105] A polypropylene cable shielding material was prepared in substantially the same manner as in Example 1, except that the toughening and compatibilizing agent a was replaced with an equal amount of tetramethyltetravinylcyclotetrasiloxane.

[0106] [Comparative Example 3]

[0107] A polypropylene cable shielding material was prepared in substantially the same manner as in Example 1, except that the oxidized carbon black a was replaced with an equal amount of conductive carbon black F500.

[0108] [Comparative Example 4]

[0109] A polypropylene cable shielding material was prepared in substantially the same manner as in Example 1, except that 70% hydrogen peroxide was replaced with a 70% diisopropylbenzene peroxide aqueous solution.

[0110] [Comparative Example 5]

[0111] A polypropylene cable shielding material was prepared in substantially the same manner as in Example 1, except that the raw material of the toughening and compatibilizing agent a was replaced by an equal amount of tetramethyl disiloxane instead of tetramethyltetravinylcyclotetrasiloxane.

[0112] The polypropylene cable shielding materials provided in the above embodiments and comparative examples were tested for the properties shown in Table 2, and the results are as follows:

[0113] Table 2. Performance test results

[0114]

[0115] It can be seen from the above test results that the thermoplastic polypropylene cable shielding material provided by each embodiment of the present invention has the characteristics of low volume resistivity and high low-temperature impact, and at the same time solves the problems of poor carbon black dispersion effect of thermoplastic polypropylene cable shielding material and poor low-temperature resistance of polypropylene.

[0116] Comparative Examples 1, 2, and 5 do not use toughening and compatibilizing agent a or use other substances instead, which has a poor dispersion effect on carbon black, resulting in poor compatibility between carbon black and polypropylene, resulting in high volume resistivity and low impact strength of the shielding material.

[0117] Comparative Example 3 does not use oxidized carbon black a, and cannot improve compatibility by grafting reaction with toughening and compatibilizing agent a, so the volume resistivity of the shielding material is still very high and the impact strength is still very low.

[0118] In Comparative Example 4, hydrogen peroxide is replaced with diisopropylbenzene peroxide, which cannot achieve the epoxidation modification of tetramethyltetravinylcyclotetrasiloxane, and it is also impossible to graft with oxidized carbon black and improve its dispersibility; in addition, the presence of diisopropylbenzene peroxide causes a cross-linking reaction between polypropylene and tetramethyltetravinylcyclotetrasiloxane, resulting in the prepared polypropylene cable shielding material being unrecyclable.

[0119] In Comparative Example 5, the raw material of toughening and compatibilizing agent a is replaced with tetramethyldisiloxane, but the raw material does not contain a functional group that can be epoxidized, and thus cannot be grafted with oxidized carbon black to improve its dispersibility. Therefore, the shielding material has a high volume resistivity and low impact strength.

[0120] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this field can make several improvements and supplements without departing from the method of the present invention. These improvements and supplements should also be regarded as the scope of protection of the present invention.

Claims

1. A thermoplastic polypropylene cable shielding material, characterized in that: The following raw materials are included in weight percentage: Polypropylene 35-75%, preferably 45-60%; Toughener 2-25%, preferably 10-20%; Toughening and compatibilizing agent 0.5-2%, preferably 1.0-1.5%; Oxidized carbon black 20-40%, preferably 25-35%; Antioxidant 0.1-1%, preferably 0.2-0.6%; Lubricant 0.1-1%, preferably 0.2-0.5%.

2. The thermoplastic polypropylene cable shielding material according to claim 1, characterized in that: The polypropylene is ethylene copolymer polypropylene, and has a melt index of 0.5 to 15 g / 10 min, preferably 1 to 10 g / 10 min, at 190° C. and 2.16 kg.

3. The thermoplastic polypropylene cable shielding material according to claim 1, characterized in that: The toughening agent is one or more of ethylene-octene copolymer, ethylene-butene copolymer, and hydrogenated styrene-butadiene block copolymer, preferably one or more of ethylene-octene copolymer, ethylene-butene copolymer, and hydrogenated styrene-butadiene block copolymer having a melt index of ≤10g / 10min at 230°C and 2.16kg.

4. The thermoplastic polypropylene cable shielding material according to claim 1, characterized in that: The toughening and compatibilizing agent is an epoxidized modified product of an unsaturated cyclic siloxane monomer, wherein the unsaturated cyclic siloxane monomer is preferably one or more of 2,4,6-trivinyl-2,4,6-trimethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and pentamethylpentavinylcyclopentasiloxane.

5. The thermoplastic polypropylene cable shielding material according to any one of claims 1 to 4, characterized in that: The oxidized carbon black is obtained by oxidizing conductive carbon black with nitric acid.

6. The thermoplastic polypropylene cable shielding material according to any one of claims 1 to 5, characterized in that: The antioxidant is selected from hindered phenol antioxidants and / or phosphite antioxidants, preferably one or two of antioxidants 1010 and 168; Preferably, the lubricant is one or more of polypropylene wax and polyethylene wax.

7. A method for preparing a thermoplastic polypropylene cable shielding material according to any one of claims 1 to 6, characterized in that: The polypropylene, toughening agent, toughening and compatibilizing agent, oxidized carbon black, antioxidant and lubricant are mixed and melt-extruded to obtain a thermoplastic polypropylene cable shielding material; Preferably, the raw materials are mixed using a high-speed mixer, and the mixing conditions are: temperature of 10 to 40°C, rotation speed of 50 to 400 rpm, preferably 100 to 300 rpm, and mixing time of 3 to 8 min, preferably 4 to 7 min; Preferably, the melt extrusion adopts a reciprocating single screw extruder, and the operating conditions are: screw temperature 180-230° C., preferably 190-220° C., and rotation speed 150-600 rpm, preferably 200-500 rpm.

8. The method for preparing thermoplastic polypropylene cable shielding material according to claim 7, characterized in that: The preparation method of the toughening and compatibilizing agent is: Under stirring conditions, unsaturated cyclic siloxane monomers and oxidants are mixed and heated for reaction; after the reaction is completed, the product is purified to obtain a toughening and compatibilizing agent; Preferably, the oxidant is one or more of hydrogen peroxide, oxygen, perbenzoic acid, peracetic acid, potassium persulfate, m-chloroperbenzoic acid, trifluoroperacetic acid, and peracetone.

9. The method for preparing a thermoplastic polypropylene cable shielding material according to claim 7 or 8, characterized in that: The preparation method of the oxidized carbon black is: Under stirring conditions, carbon black and concentrated nitric acid are mixed and reacted; after the reaction is completed, centrifugation is performed, washing is performed, and drying is performed to obtain oxidized carbon black; Preferably, the mixed reaction conditions are: 80-120° C. for 5-10 h.

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