Silicone rubber composite insulator and preparation method thereof

Abstract

The invention relates to the technical field of insulating materials, and provides a silicone rubber composite insulator and a preparation method thereof. A silicone rubber composite insulator comprises a core rod, an umbrella skirt, a sheath and a metal accessory, and raw materials of the umbrella skirt and / or the sheath comprise the following components: methyl vinyl phenyl silicone rubber, reinforced master batch, a functional additive and a vulcanizing agent, the reinforced master batch is prepared from the following components in parts by mass: 20 to 30 parts of epoxy silane modified inorganic filler, 5 to 10 parts of aminated polystyrene, 0 to 10 parts of polystyrene-polydimethylsiloxane grafted copolymer and 25 to 35 parts of methyl vinyl phenyl silicone rubber. According to the technical scheme, the problem of low mechanical strength of the silicone rubber composite insulator prepared from the epoxy silane modified inorganic filler in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of insulating materials technology, specifically to a silicone rubber composite insulator and its preparation method. Background Technology

[0002] Insulators are used to support and fix current-carrying conductors, and to insulate them from the ground, or to insulate conductors of different phases from each other. In operation, insulators are subjected to working voltage and various overvoltages, mechanical stress, and environmental stress; therefore, insulators must possess sufficient insulation strength and mechanical strength.

[0003] Composite insulators are made of organic insulating materials and consist of a core rod, sheds, a sheath, and metal fittings. The core rod is typically made of fiberglass reinforced plastic (FRP) composite material with glass fiber as reinforcement and epoxy resin as the matrix, possessing high tensile strength. The sheds and sheath are generally made of silicone rubber, an organic synthetic material. The properties of silicone rubber directly affect the performance of the composite insulator. Silicone rubber's molecular backbone is composed of Si-O, exhibiting high flexibility and high bond energy, making it resistant to aging. However, it also has drawbacks, such as relatively low mechanical strength.

[0004] Currently, inorganic fillers such as silica, diatomaceous earth, and titanium dioxide are often added to improve the mechanical strength of polymer materials. To enhance the reinforcing effect of inorganic fillers, they are often used in conjunction with silane coupling agents. Among them, epoxy silanes have highly active epoxy groups and are often used to modify inorganic fillers to improve the mechanical strength of polymer materials, but their effect on improving mechanical strength is limited. Summary of the Invention

[0005] This invention proposes a silicone rubber composite insulator and its preparation method, which solves the problem of low mechanical strength of silicone rubber composite insulators prepared by epoxy silane modified inorganic fillers in related technologies.

[0006] The technical solution of the present invention is as follows: This invention proposes a silicone rubber composite insulator, comprising a core rod, sheds, a sheath, and metal accessories. The raw materials of the sheds and / or sheath include the following components: methyl vinyl phenyl silicone rubber, reinforcing masterbatch, functional additives, and vulcanizing agent. The reinforcing masterbatch comprises the following components in parts by weight: 20-30 parts of epoxy silane modified inorganic filler, 5-10 parts of amino polystyrene, 0-10 parts of polystyrene-polydimethylsiloxane graft copolymer, and 25-35 parts of methyl vinyl phenyl silicone rubber.

[0007] Methyl vinyl phenyl silicone rubber, or simply phenyl silicone rubber, is made by introducing diphenylsiloxane segments (or methylphenylsiloxane segments) into the molecular chain of vinyl silicone rubber. This invention uses methyl vinyl phenyl silicone rubber as the matrix material for silicone rubber composite insulators, providing excellent low-temperature resistance to the composite insulators.

[0008] As a further technical solution, the mass fraction of the polystyrene-polydimethylsiloxane graft copolymer is not 0.

[0009] In this invention, based on the addition of aminated polystyrene, a polystyrene-polydimethylsiloxane graft copolymer is further introduced, which further improves the compatibility between the epoxy silane-modified inorganic filler and the methyl vinyl phenyl silicone rubber matrix, thereby achieving the effect of further improving the mechanical strength of the silicone rubber composite insulator prepared by the epoxy silane-modified inorganic filler.

[0010] As a further technical solution, the mass ratio of the epoxy silane modified inorganic filler, amino polystyrene, and polystyrene-polydimethylsiloxane graft copolymer is 20:6~7:3~4.

[0011] In this invention, the mass ratio of epoxy silane-modified inorganic filler, amino-modified polystyrene, and polystyrene-polydimethylsiloxane graft copolymer is limited to 20:6~7:3~4, which further improves the mechanical strength of the silicone rubber composite insulator prepared by epoxy silane-modified inorganic filler.

[0012] In this invention, the amounts of methyl vinyl phenyl silicone rubber, reinforcing masterbatch, functional additives, and vulcanizing agent can be any conventional amounts used in the art. Preferably, the mass ratio of the methyl vinyl phenyl silicone rubber, reinforcing masterbatch, functional additives, and vulcanizing agent is 85:55~70:5~10:2~4.

[0013] In this invention, the functional additives can be any conventional functional additives in the art, such as plasticizers, mold release agents, anti-scorching agents, pigments, flame retardants, structure control agents, vulcanization aids, anti-yellowing agents, etc. Preferably, the functional additives include one or more of mold release agents, structure control agents, vulcanization aids, and anti-yellowing agents. More preferably, the functional additives are composed of mold release agents, structure control agents, and anti-yellowing agents in a mass ratio of 1~3:5:0.5~1.

[0014] As a further technical solution, the vulcanizing agent includes one or both of vulcanizing agent bis-25 and vulcanizing agent DCP.

[0015] As a further technical solution, the method for preparing the enhanced masterbatch includes the following steps: A1. Mix the remaining components except for the epoxy silane-modified inorganic filler, then extrude and granulate to obtain granules; A2. The granules are mixed with epoxy silane-modified inorganic fillers and then extruded and granulated to obtain reinforced masterbatch.

[0016] In this invention, the inorganic filler in the epoxy silane modified inorganic filler can be any conventional reinforcing inorganic filler in the art, such as silica, glass fiber, diatomaceous earth, talc, titanium dioxide, etc. Preferably, the inorganic filler in the epoxy silane modified inorganic filler includes one or two of silica and titanium dioxide. More preferably, the inorganic filler in the epoxy silane modified inorganic filler is silica.

[0017] In this invention, the epoxy silane in the epoxy-modified inorganic filler can be any conventional epoxy-containing silane in the art, such as KH-560, KH-781, KH-561, KH-1770, KH-1771, KH-78, etc. Preferably, the epoxy silane in the epoxy-modified inorganic filler includes one or more of KH-560, KH-781, and KH-561. More preferably, the epoxy silane in the epoxy-modified inorganic filler is KH-560.

[0018] This invention also proposes a method for preparing a silicone rubber composite insulator, comprising the following steps: B1. After assembling the mandrel and metal accessories, a semi-finished product is obtained; B2. After mixing methyl vinyl phenyl silicone rubber, reinforcing masterbatch, and functional additives, a vulcanizing agent is added and the mixture is rolled into a mold cavity of the semi-finished product and vulcanized to obtain a silicone rubber composite insulator.

[0019] The working principle and beneficial effects of this invention are as follows: In this invention, epoxy-silane modified inorganic filler, amino-modified polystyrene, and methyl vinyl phenyl silicone rubber are used as reinforcing masterbatches. Amino-modified polystyrene has a "bridging" effect between epoxy-silane modified inorganic filler and methyl vinyl phenyl silicone rubber, which improves the compatibility of epoxy-silane modified inorganic filler in methyl vinyl phenyl silicone rubber matrix and achieves the effect of improving the mechanical strength of silicone rubber composite insulators made from epoxy-silane modified inorganic filler. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In the following embodiments and comparative examples: Methyl vinyl phenyl silicone rubber: grade IOTA R33, purchased from Anhui Aiyota Silicone Oil Co., Ltd.; Dimethyl silicone oil: Dow Corning Dimethyl Silicone Oil PMX-200, 350 viscosity; Hydroxy silicone oil: Dow hydroxy silicone oil PMX-0930; Hydrogen-containing silicone oil: Dow Corning 1107 hydrogen-containing silicone oil MHX-1107, 20 viscosity.

[0022] Aminated polystyrene is prepared by the following method: Mix 6.5 mL of 98 wt% concentrated sulfuric acid with 25 mL of 65 wt% concentrated nitric acid until homogeneous to obtain a mixed acid; After 6g of polystyrene (Mw=14w) was swollen in 40mL of chloroform, the above mixed acid was added dropwise. After the addition was complete, the mixture was reacted at 25℃ for 5h. The mixture was then transferred to a separatory funnel and allowed to stand to separate into layers. The lower layer was separated, and the upper pale yellow liquid was added dropwise to anhydrous ethanol (the volume ratio of pale yellow liquid to anhydrous ethanol was 1:50) with stirring. A pale yellow flocculent solid precipitated out. The solid was filtered and repeatedly washed with anhydrous ethanol. After filtration until neutral, the solid was dried to obtain nitrated polystyrene. Dissolve 3g of the above-mentioned nitropolystyrene in 20mL of DMF and transfer it to a constant pressure dropping funnel to obtain a nitropolystyrene-DMF solution. Mix 60mL of 37wt% concentrated hydrochloric acid with 8.78g of iron powder in a four-necked flask, turn on the stirrer and cooling water, heat to 65℃, and add the nitropolystyrene-DMF solution dropwise while stirring. After the addition is complete, raise the temperature to 100℃ and stir continuously for 15h. Filter to obtain a light yellow powder. Wash with deionized water first, filter, wash twice with deionized water, then wash with 5wt% NaOH aqueous solution, and then wash with deionized water until neutral. Dry to obtain aminopolystyrene.

[0023] The polystyrene-polydimethylsiloxane graft copolymer was prepared by the following method: Styrene and a double-bonded organosilicon macromolecule (Mw=15000, with one double bond at the end group, purchased from Zhuhai Hezhong Chemical Co., Ltd.) were mixed at a mass ratio of 9:1. Azobisisoheptanenitrile (0.4% of the total mass of styrene and the double-bonded organosilicon macromolecule) was added, and the mixture was reacted at 60℃ for 24 h. After precipitation with ethanol, the first product was dissolved in a mixed solvent of cyclohexane and n-hexane (mass ratio of the first product, cyclohexane, and n-hexane was 1:25:1.2). The mixture was centrifuged at 0℃ and 2000 rpm for 20 min, and the supernatant was poured off. The second product was obtained by rotary evaporation, dried at 60℃, extracted with n-hexane for 24 h, and dried at 60℃ to obtain a polystyrene-polydimethylsiloxane graft copolymer.

[0024] Epoxy-based silane-modified inorganic fillers were prepared by the following method: Add silica (Wacker fumed silica N20) to ethanol (the mass-volume ratio of silica to ethanol is 3g:100mL), stir at 350rpm for 10min, and then sonicate until uniformly dispersed to obtain a silica suspension. Anhydrous ethanol and KH-560 (volume ratio of anhydrous ethanol to KH-560 is 3:2) were mixed evenly and then added to the above silica suspension at a ratio of silica:KH-560=3g:40mL. The mixture was refluxed at 70℃ for 6h, filtered, washed, and dried to obtain epoxy silane modified inorganic filler.

[0025] Example 1 A silicone rubber composite insulator includes a core rod, sheds, a sheath, and metal fittings. The raw materials for the sheds and sheath include the following components in parts by weight: 85 parts of methyl vinyl phenyl silicone rubber, 55 parts of reinforcing masterbatch, 1 part of dimethyl silicone oil, 5 parts of hydroxyl silicone oil, 1 part of hydrogen-containing silicone oil, and 2 parts of vulcanizing agent bis-25. The reinforcing masterbatch includes the following components in parts by weight: 20 parts of epoxy silane modified inorganic filler, 10 parts of amino polystyrene, and 25 parts of methyl vinyl phenyl silicone rubber. The method for preparing reinforced masterbatch includes the following steps: The remaining components, except for the epoxy silane-modified inorganic filler, are mixed and then extruded and granulated to obtain granules. The above granules were mixed with epoxy silane-modified inorganic fillers and then extruded and granulated to obtain reinforced masterbatch. The preparation method of silicone rubber composite insulators includes the following steps: After assembling the core rod and metal accessories, a semi-finished product is obtained. Methyl vinyl phenyl silicone rubber, reinforcing masterbatch, dimethyl silicone oil, hydroxyl silicone oil and hydrogen-containing silicone oil are mixed and then rolled on a two-roll mill. The vulcanizing agent bis-25 is added, the mixture is sheeted out, transferred to the mold cavity of the semi-finished product, and vulcanized to obtain a silicone rubber composite insulator.

[0026] Example 2 A silicone rubber composite insulator includes a core rod, sheds, a sheath, and metal fittings. The raw materials for the sheds and sheath include the following components in parts by weight: 85 parts methyl vinyl phenyl silicone rubber, 70 parts reinforcing masterbatch, 3 parts dimethyl silicone oil, 5 parts hydroxyl silicone oil, 0.5 parts hydrogen-containing silicone oil, and 4 parts vulcanizing agent DCP. The reinforcing masterbatch includes the following components in parts by weight: 30 parts epoxy silane modified inorganic filler, 5 parts amino-modified polystyrene, and 35 parts methyl vinyl phenyl silicone rubber. The method for preparing reinforced masterbatch includes the following steps: The remaining components, except for the epoxy silane-modified inorganic filler, are mixed and then extruded and granulated to obtain granules. The above granules were mixed with epoxy silane-modified inorganic fillers and then extruded and granulated to obtain reinforced masterbatch. The preparation method of silicone rubber composite insulators includes the following steps: After assembling the core rod and metal accessories, a semi-finished product is obtained. Methyl vinyl phenyl silicone rubber, reinforcing masterbatch, dimethyl silicone oil, hydroxyl silicone oil and hydrogen-containing silicone oil are mixed and then rolled on a two-roll mill. The vulcanizing agent DCP is added and the mixture is sheeted out and transferred to the mold cavity of the semi-finished product for vulcanization to obtain a silicone rubber composite insulator.

[0027] Example 3 The only difference from Example 1 is that the aminated polystyrene is replaced with equal amounts of aminated polystyrene and polystyrene-polydimethylsiloxane graft copolymer in a mass ratio of 1:1.

[0028] Example 4 The only difference from Example 1 is that the aminated polystyrene is replaced with equal amounts of aminated polystyrene and polystyrene-polydimethylsiloxane graft copolymer in a mass ratio of 3:2.

[0029] Example 5 The only difference from Example 1 is that the aminated polystyrene is replaced with equal amounts of aminated polystyrene and polystyrene-polydimethylsiloxane graft copolymer in a mass ratio of 7:3.

[0030] Example 6 The only difference from Example 1 is that the aminated polystyrene is replaced with equal amounts of aminated polystyrene and polystyrene-polydimethylsiloxane graft copolymer in a mass ratio of 9:1.

[0031] Comparative Example 1 A silicone rubber composite insulator includes a core rod, sheds, a sheath, and metal fittings. The raw materials for the sheds and sheath include the following components by weight: 120 parts of methyl vinyl phenyl silicone rubber, 20 parts of epoxy silane modified inorganic filler, 1 part of dimethyl silicone oil, 5 parts of hydroxyl silicone oil, 1 part of hydrogen-containing silicone oil, and 2 parts of vulcanizing agent bis-25. The preparation method of silicone rubber composite insulators includes the following steps: After assembling the core rod and metal accessories, a semi-finished product is obtained. Methyl vinyl phenyl silicone rubber, epoxy silane modified inorganic filler, dimethyl silicone oil, hydroxyl silicone oil and hydrogen-containing silicone oil are mixed and then rolled on a two-roll mill. The vulcanizing agent double-25 is added and the mixture is sheeted out and transferred to the mold cavity of the semi-finished product for vulcanization to obtain a silicone rubber composite insulator.

[0032] The above-mentioned vulcanized silicone rubber composite material was subjected to the following performance tests: (1) Tensile strength: Refer to the method in GB / T 528-2009, use dumbbell-shaped specimens, specimen type 1, thickness 2mm, tensile speed 500mm / min; (2) Breakdown strength: Refer to the method in GB / T 1408.2-2016; The test results are recorded in Table 1 and Table 2.

[0033] Table 1 Tensile strength test results of silicone rubber composites

[0034] As can be seen from Table 1, compared with Comparative Example 1, the silicone rubber composite materials obtained in Examples 1-6 have higher tensile strength, indicating that using epoxy silane-modified inorganic filler, amino-modified polystyrene, and methyl vinyl phenyl silicone rubber as reinforcing masterbatch improves the mechanical strength of silicone rubber composite insulators made from epoxy silane-modified inorganic filler.

[0035] Table 2 Breakdown strength test results of silicone rubber composites

[0036] As can be seen from Table 2, the silicone rubber composite material provided by the present invention has good insulation properties.

[0037] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A silicone rubber composite insulator, characterized by, The umbrella skirt and / or sheath are made of the following components: methyl vinyl phenyl silicone rubber, reinforcing masterbatch, functional additives, vulcanizing agent, the reinforcing masterbatch is made of the following components by mass: epoxy silane modified inorganic filler 20-30 parts, aminated polystyrene 5-10 parts, polystyrene-polydimethylsiloxane graft copolymer 0-10 parts, methyl vinyl phenyl silicone rubber 25-35 parts.

2. A silicone rubber composite insulator according to claim 1, characterised in that, The mass ratio of the epoxy silane modified inorganic filler, aminated polystyrene, and polystyrene-polydimethylsiloxane graft copolymer is 20:6-7:3-4.

3. A silicone rubber composite insulator according to claim 1, characterised in that, The mass ratio of the methyl vinyl phenyl silicone rubber, reinforcing masterbatch, functional additives, and vulcanizing agent is 85:55-70:5-10:2-4.

4. A silicone rubber composite insulator according to claim 1, characterised in that, The functional additives include one or more of release agents, structure control agents, vulcanization aids, and anti-yellowing agents.

5. A silicone rubber composite insulator according to claim 4, characterised in that, The functional additives are composed of release agents, structure control agents, and anti-yellowing agents in a mass ratio of 1-3:5:0.5-1.

6. A silicone rubber composite insulator according to claim 1, wherein The vulcanizing agent includes one or both of vulcanizing agent bis-25 and vulcanizing agent DCP.

7. A silicone rubber composite insulator according to claim 1, wherein The preparation method of the reinforcing masterbatch includes the following steps: A1, after mixing the remaining components except for the epoxy silane modified inorganic filler, extruding and granulating to obtain granules; A2, after mixing the granules with the epoxy silane modified inorganic filler, extruding and granulating to obtain the reinforcing masterbatch.

8. A silicone rubber composite insulator according to claim 1, wherein The inorganic filler in the epoxy silane modified inorganic filler includes one or both of white carbon black and titanium dioxide.

9. A silicone rubber composite insulator according to claim 1, wherein The epoxy silane in the epoxy silane modified inorganic filler includes one or more of KH-560, KH-781, and KH-561.

10. A method for producing a silicone rubber composite insulator for producing the silicone rubber composite insulator according to any one of claims 1 to 9, characterized by, The method includes the following steps: B1, after assembling the core rod and metal accessories, a semi-finished product is obtained; B2, after mixing the methyl vinyl phenyl silicone rubber, reinforcing masterbatch, and functional additives, adding the vulcanizing agent to open mill, transferring to the mold cavity of the semi-finished product, and vulcanizing and forming, a silicone rubber composite insulator is obtained.

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