Rubber composition, cable sheath material, cable and preparation method

Abstract

The present invention belongs to the technical field of cable materials, and in particular to a rubber composition, a cable sheath, a cable and a preparation method. The rubber composition of the present invention comprises ethylene-vinyl acetate copolymer, a polyolefin elastomer, a compatibilizer, a flame retardant, an antioxidant A, an antioxidant B, a crosslinking agent, a radiation protection agent and a lubricant; the antioxidant A is selected from one or more of 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-p-cresol and styrenated phenol; the antioxidant B is selected from one or more of 2-mercaptobenzimidazole zinc salt, N,N'-di(β-naphthyl)-p-phenylenediamine and N-(1-methylisoamyl)-N'-phenyl-p-phenylenediamine. The cable sheath made of the rubber composition of the present invention has efficient flame retardant performance and anti-aging performance, can meet the life requirement of 80 years (90°C) of a nuclear power plant, and can work normally under mild conditions of a nuclear power plant.

Description

Technical Field

[0001] The invention belongs to the technical field of cable materials, and in particular relates to a rubber composition, a cable sheathing material, a cable and a preparation method. Background Art

[0002] At present, nuclear power plant nuclear safety-grade cables are all certified according to a design life of 60 years. However, due to the large number of cables involved in the construction of nuclear power plants, re-laying will result in huge manpower and material costs, and will also cause fire blocking and other work to be re-constructed. In addition, since the cable laying channel may be quite narrow in some parts and equipment is difficult to enter, it is extremely difficult to re-lay the cables. Some areas are even prohibited for personnel to enter, which makes it impossible to complete the cable replacement work, which puts higher requirements on the life of nuclear safety-grade cables.

[0003] Therefore, there is an urgent need to develop a cable material with a longer service life. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a rubber composition, a cable sheath material, a cable and a preparation method. The cable sheath material prepared from the rubber composition of the present invention has high-efficiency flame retardant and anti-aging properties, and under the synergistic effect of an antioxidant, can meet the 80-year (90° C.) life requirement of a nuclear power plant, and can work normally under mild conditions in a nuclear power plant.

[0005] Specifically, the present invention provides a rubber composition, which comprises 60-80 parts by mass of ethylene-vinyl acetate copolymer, 10-30 parts by mass of polyolefin elastomer, 10-20 parts by mass of compatibilizer, 150-180 parts by mass of flame retardant, 3-5 parts by mass of antioxidant A, 3-5 parts by mass of antioxidant B, 1-3 parts by mass of cross-linking agent, 1-2 parts by mass of radiation protection agent and 0.5-2 parts by mass of lubricant; the antioxidant A is selected from one or more of 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-p-cresol and styrenated phenol; the antioxidant B is selected from one or more of 2-mercaptobenzimidazole zinc salt, N,N'-di(β-naphthyl)-p-phenylenediamine and N-(1-methylisopentyl)-N`-phenyl-p-phenylenediamine.

[0006] In one or more embodiments, the ethylene-vinyl acetate copolymer is selected from one or more of EVA150, EVA180, EVA40L-03 and EVA2803.

[0007] In one or more embodiments, the polyolefin elastomer is selected from one or more of ethylene-octene copolymers, ethylene-propylene copolymers, ethylene-butene copolymers, and ethylene-hexene copolymers.

[0008] In one or more embodiments, the compatibilizer is selected from one or more of maleic anhydride grafted polyethylene, ethylene-acrylic acid copolymer, maleic anhydride grafted polypropylene, and maleic anhydride modified alpha olefin copolymer.

[0009] In one or more embodiments, the crosslinking agent is selected from one or more of dicumyl peroxide, triallyl hydroxyurate, triallyl isocyanurate, and trimethylolpropane trimethacrylate.

[0010] In one or more embodiments, the flame retardant is selected from one or more of magnesium hydroxide, antimony trioxide, zinc borate, aluminum hydroxide, kaolin, and montmorillonite.

[0011] In one or more embodiments, the radiation protection agent is selected from one or more of lead sulfate, barium sulfate, gadolinium oxide, and boron carbide.

[0012] In one or more embodiments, the lubricant is selected from one or more of paraffin wax, polyethylene wax, stearic acid, and butyl stearate.

[0013] The invention provides a cable sheath material prepared from the rubber composition of the invention.

[0014] The present invention provides a method for preparing the cable sheathing material of the present invention, the method comprising the following steps:

[0015] (a) putting ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, flame retardant, antioxidant A, antioxidant B, crosslinking agent, radiation protection agent and lubricant into an internal mixer for first internal mixing, cleaning after the first internal mixing, and then performing a second internal mixing to obtain a bulk material;

[0016] (b) The bulk material is put into a twin-screw extruder for mixing, and then granulated by a single-screw extruder to obtain a cable sheath material.

[0017] In one or more embodiments, the temperature of the first mixing is 110-130°C.

[0018] In one or more embodiments, the temperature of the second internal mixing is 125-140°C.

[0019] In one or more embodiments, the temperature in the feed zone of the twin screw extruder is 110-120°C.

[0020] In one or more embodiments, the temperature of the conveying section in the twin-screw extruder is 100-120°C.

[0021] In one or more embodiments, the temperature of the melt zone in the twin screw extruder is from 95°C to 115°C.

[0022] In one or more embodiments, the temperature of the die in the twin-screw extruder is 80-100°C.

[0023] In one or more embodiments, the temperature in the feed zone of the single screw extruder is 80-100°C.

[0024] In one or more embodiments, the temperature of the compression section in the single screw extruder is 90-110°C.

[0025] In one or more embodiments, the temperature of the homogenization zone in the single screw extruder is 100-120°C.

[0026] The present invention provides a cable comprising the cable sheathing material of the present invention; preferably, the cable is a cable for a nuclear power plant. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0028] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0029] Herein, “comprising”, “including”, “containing” and similar terms encompass the meanings of “consisting essentially of” and “consisting of”. For example, when “A comprises B and C” is disclosed herein, “A consists essentially of B and C” and “A consists of B and C” should be deemed to be disclosed herein.

[0030] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0031] In this document, unless otherwise specified, percentage refers to mass percentage and ratio refers to mass ratio.

[0032] Herein, when describing embodiments or examples, it should be understood that they are not used to limit the present invention to these embodiments or examples. On the contrary, all substitutes, improvements and equivalents of the methods and materials described in the present invention can be included in the scope limited by the claims.

[0033] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0034] The invention provides a rubber composition, which may contain 60-80 parts by mass of ethylene-vinyl acetate copolymer, 10-30 parts by mass of polyolefin elastomer, 10-20 parts by mass of compatibilizer, 150-180 parts by mass of flame retardant, 1-3 parts by mass of antioxidant A, 1-3 parts by mass of antioxidant B, 1-3 parts by mass of crosslinking agent, 1-2 parts by mass of radiation protection agent and 0.5-2 parts by mass of lubricant. In the present invention, antioxidant A can be one or more selected from 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (antioxidant 2246), 2,6-di-tert-butyl-p-cresol (antioxidant 264) and styrenated phenol (antioxidant SP); antioxidant B can be one or more selected from 2-mercaptobenzimidazole zinc salt (antioxidant MBZ), N,N'-di(β-naphthyl)-p-phenylenediamine (antioxidant DNP) and N-(1-methylisoamyl)-N'-phenyl-p-phenylenediamine (antioxidant 4020). The inventors of the present invention have found that antioxidant A and antioxidant B have a synergistic effect in the rubber composition of the present invention. The combined use of the two antioxidants significantly improves the service life of the cable, which can meet the 80-year (90°C) service life requirement of the nuclear power plant and can work normally under mild conditions of the nuclear power plant. In the present invention, there is a synergistic effect between the ethylene-vinyl acetate copolymer, the polyolefin elastomer, the compatibilizer, the flame retardant, the antioxidant A, the antioxidant B, the crosslinking agent, the radiation protection agent and the lubricant, which can ensure that the cable sheath material containing the rubber composition of the present invention has excellent flame retardant properties, mechanical properties and electrical properties, and improve the anti-aging performance and life of the cable sheath material containing the rubber composition of the present invention.

[0035] In the rubber composition of the present invention, the ethylene-vinyl acetate copolymer can be one or more selected from EVA150, EVA180, EVA40L-03 and EVA2803. In the rubber composition of the present invention, the polyolefin elastomer can be one or more selected from ethylene-octene copolymer, ethylene-propylene copolymer, ethylene-butene copolymer and ethylene-hexene copolymer. In the rubber composition of the present invention, the compatibilizer can be one or more selected from maleic anhydride grafted polyethylene, ethylene-acrylic acid copolymer, maleic anhydride grafted polypropylene and maleic anhydride modified alpha olefin copolymer. In the present invention, the crosslinking agent is selected from diisopropylbenzene peroxide, triallyl hydroxyurate (TAC), triallyl isocyanurate (TAIC) and trimethylolpropane trimethacrylate (TMPTMA). In the rubber composition of the present invention, the flame retardant can be one or more selected from magnesium hydroxide, antimony trioxide, zinc borate, aluminum hydroxide, kaolin and montmorillonite. In the rubber composition of the present invention, the radiation protection agent may be one or more selected from lead sulfate, barium sulfate, gadolinium oxide and boron carbide; in the rubber composition of the present invention, the lubricant may be one or more selected from paraffin, polyethylene wax, stearic acid and butyl stearate.

[0036] The present invention provides a cable sheath prepared from the rubber composition of the present invention. In the present invention, there is a synergistic effect between the ethylene-vinyl acetate copolymer, the polyolefin elastomer, the compatibilizer, the flame retardant, the antioxidant A, the antioxidant B, the crosslinking agent, the radiation protection agent and the lubricant, which can ensure that the cable sheath containing the rubber composition of the present invention is a precursor of a low-smoke, halogen-free flame-retardant sheath material, and improve the life of the cable sheath containing the rubber composition of the present invention. The present invention provides a cable containing the cable sheath of the present invention; preferably, the cable can be a nuclear power plant cable.

[0037] The present invention provides a method for preparing the cable sheathing material of the present invention, the method comprising the following steps:

[0038] (a) putting ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, flame retardant, antioxidant A, antioxidant B, crosslinking agent, radiation protection agent and lubricant into an internal mixer for first internal mixing, cleaning after the first internal mixing, and then performing a second internal mixing to obtain a bulk material;

[0039] (b) The bulk material is put into a twin-screw extruder for mixing, and then granulated by a single-screw extruder to obtain a cable sheath material.

[0040] In the process of preparing the cable sheathing material of the present invention, the temperature of the first banburying may be 110-130°C, for example, 110°C, 115°C, 120°C, 125°C, 130°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the second banburying is 125-140°C, for example, 125°C, 130°C, 135°C, 140°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the feeding section in the twin-screw extruder may be 110-120°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the conveying section in the twin-screw extruder may be 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the melting section in the twin-screw extruder may be 95-115°C, for example, 95°C, 100°C, 105°C, 110°C, 115°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the die head in the twin-screw extruder can be 80-100°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C. The temperature of the feeding section in the single-screw extruder can be 80-100°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the compression section in the single-screw extruder can be 90-110°C, for example, 90°C, 95°C, 100°C, 105°C, 110°C. In the process of preparing the cable sheathing material of the present invention, the temperature of the homogenizing section in the single-screw extruder can be 100-120°C, for example, 100°C, 105°C, 110°C, 115°C, 120°C.

[0041] Compared with the prior art, the present invention has the following beneficial technical effects: the present invention increases the service life of cables used in nuclear power plants from 60 years to 80 years.

[0042] The present invention will be described below in the form of specific examples. It should be understood that these examples are merely illustrative and are not intended to limit the scope of the present invention. The methods, reagents and materials used in the examples are, unless otherwise stated, conventional methods, reagents and materials in the art. The raw material compounds in the examples can all be purchased through commercial routes.

[0043] The ethylene-vinyl acetate copolymer EVA2803 in the embodiment of the present invention is purchased from Arkema, France.

[0044] The ethylene-octene copolymer POE840 in the examples of the present invention was purchased from Mitsui Chemicals of Japan.

[0045] The maleic anhydride modified α-olefin copolymer MH7010 in the embodiment of the present invention is purchased from Mitsui Chemicals of Japan.

[0046] Examples 1-3

[0047] According to the formula of the rubber composition shown in Table 1, the cable sheath materials of Examples 1-3 were prepared by the following process:

[0048] (1) Ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, flame retardant, antioxidant A, antioxidant B, cross-linking agent, radiation protection agent and lubricant are put into an internal mixer, and after internal mixing to 120 degrees, the upper top bolt is raised, the sprayed powder is cleaned, and the material is turned over; then the upper top bolt is pressed down, and the material is internally mixed to 140 degrees and discharged; (2) The internally mixed material blocks are transferred to a double-cone feeding system and further mixed by a twin-screw extruder. The temperature of the twin-screw is set as follows: the temperature of the feeding section is 110°C, the temperature of the conveying section is 120°C, the temperature of the melting section is 105°C, and the temperature of the die head is 95°C; after mixing, a single-screw extruder is used for granulation. The temperature of the single-screw is set as follows: the temperature of the feeding section is 90°C, the temperature of the compression section is 110°C, and the temperature of the homogenizing section is 115°C. Finally, the material is sent to the silo by an air conveying system, packaged and stored, and the cable sheath material is obtained.

[0049] Table 1: Formulation of the rubber composition in Examples 1-3

[0050]

[0051] Test Case

[0052] The cable sheath materials prepared in Examples 1-3 were tested for their performance, and the performance is shown in Table 2.

[0053] Table 2: Properties of cable sheathing materials obtained in Examples 1-3

[0054]

[0055]

[0056]

[0057] As can be seen from Table 2, the cable sheath material prepared by the present invention is a low-smoke halogen-free flame-retardant sheath material, which not only has excellent flame retardant properties, good mechanical properties, and superior electrical properties, but can also meet the requirements for use in a mild environment in a nuclear power plant; and the cable sheath material of the present invention has good aging resistance, and can have a thermal life of 80 years at 90°C, and has broad application prospects.

Claims

1. A rubber composition, characterized in that: The rubber composition comprises 60-80 parts by mass of ethylene-vinyl acetate copolymer, 10-30 parts by mass of polyolefin elastomer, 10-20 parts by mass of compatibilizer, 150-180 parts by mass of flame retardant, 3-5 parts by mass of antioxidant A, 3-5 parts by mass of antioxidant B, 1-3 parts by mass of crosslinking agent, 1-2 parts by mass of radiation protection agent and 0.5-2 parts by mass of lubricant; the antioxidant A is selected from one or more of 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,6-di-tert-butyl-p-cresol and styrenated phenol; the antioxidant B is selected from one or more of 2-mercaptobenzimidazole zinc salt, N,N'-di(β-naphthyl)-p-phenylenediamine and N-(1-methylisopentyl)-N`-phenyl-p-phenylenediamine.

2. The rubber composition according to claim 1, characterized in that The ethylene-vinyl acetate copolymer is selected from one or more of EVA150, EVA180, EVA 40L-03 and EVA2803.

3. The rubber composition according to claim 1, characterized in that The polyolefin elastomer is selected from one or more of ethylene-octene copolymer, ethylene-propylene copolymer, ethylene-butene copolymer and ethylene-hexene copolymer.

4. The rubber composition according to claim 1, characterized in that The compatibilizer is selected from one or more of maleic anhydride grafted polyethylene, ethylene-acrylic acid copolymer, maleic anhydride grafted polypropylene and maleic anhydride modified alpha olefin copolymer.

5. The rubber composition according to claim 1, characterized in that The crosslinking agent is selected from one or more of dicumyl peroxide, triallyl hydroxyurate, triallyl isocyanurate and trimethylolpropane trimethacrylate.

6. The rubber composition according to claim 1, characterized in that: The rubber composition has one or more of the following characteristics: The flame retardant is selected from one or more of magnesium hydroxide, antimony trioxide, zinc borate, aluminum hydroxide, kaolin and montmorillonite; The radiation protection agent is selected from one or more of lead sulfate, barium sulfate, gadolinium oxide and boron carbide; The lubricant is selected from one or more of paraffin wax, polyethylene wax, stearic acid and butyl stearate.

7. A cable sheath, characterized in that: The cable sheath material is prepared from the rubber composition according to any one of claims 1 to 6.

8. A method for preparing the cable sheathing material according to claim 7, characterized in that: The method comprises the following steps: (a) putting ethylene-vinyl acetate copolymer, polyolefin elastomer, compatibilizer, flame retardant, antioxidant A, antioxidant B, crosslinking agent, radiation protection agent and lubricant into an internal mixer for first internal mixing, cleaning after the first internal mixing, and then performing a second internal mixing to obtain a bulk material; (b) The bulk material is put into a twin-screw extruder for mixing, and then granulated by a single-screw extruder to obtain a cable sheath material.

9. The method according to claim 8, characterized in that The method has one or more of the following features: The temperature of the first mixing is 110-130℃; The temperature of the second mixing is 125-140℃; The temperature of the feeding section in the twin-screw extruder is 110-120°C; The temperature of the conveying section in the twin-screw extruder is 100-120°C; The temperature of the melting section in the twin-screw extruder is 95-115°C; The temperature of the die head in the twin-screw extruder is 80-100°C; The temperature of the feeding section in the single screw extruder is 80-100°C; The temperature of the compression section in a single screw extruder is 90-110°C; The temperature of the homogenizing section in the single screw extruder is 100-120°C.

10. A cable comprising the cable sheathing material according to claim 7; preferably, the cable is a cable for a nuclear power plant.

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