Silicone rubber composition and high-strength weather-resistant silicone rubber wire and cable

Abstract

This invention belongs to the technical field of silicone rubber and wire and cable materials, specifically relating to a silicone rubber composition and a high-strength weather-resistant silicone rubber wire and cable. The silicone rubber composition comprises the following components by weight: 60-100 parts methyl vinyl silicone rubber; 10-30 parts vinyl-modified reinforcing filler; 10-30 parts alkoxy-modified reinforcing filler; 10-30 parts hydroxyl silicone oil; 1-3 parts vulcanizing agent; and 0.5-1 part accelerator. The high-strength weather-resistant silicone rubber wire and cable comprises, from the inside out, a metal core, an insulation layer, a fiberglass cloth layer, and a silicone rubber protective layer; the silicone rubber protective layer is obtained by coating the above-mentioned silicone rubber composition and then vulcanizing it. The silicone rubber composition of this invention uses vinyl-modified reinforcing filler, alkoxy-modified reinforcing filler, and hydroxyl silicone oil in combination, which can significantly improve the mechanical properties of the silicone rubber protective layer and the composite strength with the fiberglass cloth.

Description

Technical Field

[0001] The invention belongs to the technical field of silicone rubber and wire and cable materials, and specifically relates to a silicone rubber composition and a high-strength weather-resistant silicone rubber wire and cable. Background Art

[0002] Silicone rubber wires are widely used in various industries due to their excellent heat resistance, insulation and flexibility. Silicone rubber wires include a metal core and a silicone sheath wrapped around the metal core. However, silicone rubber wires have an obvious weakness, which is that the tensile strength is not enough, which is almost the lowest among the commonly used insulating materials for wires. In order to increase the tensile strength of silicone rubber wires, it is necessary to add a glass fiber layer in the middle of the silicone sheath to strengthen the tensile strength of silicone rubber wires. However, the surface energy difference between the glass fiber layer and silicone rubber is large, and the glass fiber layer is a woven material that easily absorbs moisture, while silicone rubber is highly hydrophobic. When the silicone sheath is extruded, there is an interface separation, which makes the bonding force between the two weak. Under stress and weather aging, the silicone sheath is prone to tearing, resulting in the exposure of the glass fiber layer, which reduces the service life of the silicone rubber wire.

[0003] Patent CN 1339164A discloses a flame retardant silicone rubber wire and cable coating composition, which contains: (A) 30-90 wt% of a thermosetting organosiloxane polymer containing at least 2 alkenyl groups per molecule, (B) 1-65 wt% of a reinforcing silica filler based on the total composition, (C) 5-70 wt% of wollastonite with an average particle size of 2-30 μm based on the total composition, and (D) a curing component sufficient to cure the composition. It is mainly used to solve the problem that silicone rubber has unexpectedly good flame retardancy when burning and forms a hard charred product. However, there is no corresponding record on improving the bonding effect between silicone rubber and glass fiber layer and improving the strength and weather resistance of silicone rubber. Summary of the invention

[0004] In view of the shortcomings and deficiencies of the above prior art, the primary purpose of the present invention is to provide a silicone rubber composition and a preparation method thereof.

[0005] Another object of the present invention is to provide a high-strength weather-resistant silicone rubber wire and cable.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned high-strength weather-resistant silicone rubber wire and cable.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A silicone rubber composition comprising the following components in parts by weight:

[0009] 60-100 parts of methyl vinyl silicone rubber;

[0010] 10 to 30 parts of vinyl modified reinforcing filler;

[0011] 10 to 30 parts of alkoxy modified reinforcing filler;

[0012] 10-30 parts of hydroxy silicone oil;

[0013] 1 to 3 parts of vulcanizing agent;

[0014] Accelerator 0.5 to 1 part.

[0015] Furthermore, the vinyl content of the methyl vinyl silicone rubber is 0.05% to 0.5% (mol), and the weight average molecular weight is 300,000 to 700,000. It is a commonly used silicone rubber raw material in the art.

[0016] Furthermore, the vinyl-modified reinforcing filler is a reinforcing filler modified by a vinyl silane coupling agent; the reinforcing filler is selected from at least one of silicon dioxide, aluminum hydroxide, and magnesium hydroxide.

[0017] Furthermore, the preparation method of the vinyl modified reinforcing filler is:

[0018] The reinforcing filler is added to an organic solvent and dispersed evenly, and then a vinyl silane coupling agent is added. The temperature is raised to 30-60° C. under normal air conditions, and the mixture is stirred for reaction for 0.5-2 hours. The mixture is vacuum spray-dried to obtain a vinyl-modified reinforcing filler.

[0019] Furthermore, the vinyl silane coupling agent is selected from vinyl trimethoxy silane or vinyl triethoxy silane; the added amount of the vinyl silane coupling agent is 5% to 15% of the mass of the reinforcing filler.

[0020] Furthermore, the preparation method of the alkoxy modified reinforcing filler is:

[0021] The vinyl modified reinforcing filler is added to an organic solvent and dispersed evenly, the temperature is raised to 60-100° C. under nitrogen protection, and then trialkoxyhydrosilane and chloroplatinic acid catalyst are added and stirred to react for 2-4 hours, and vacuum spray drying is performed to obtain an alkoxy modified reinforcing filler.

[0022] Furthermore, the trialkoxy hydrogen silane is selected from trimethoxy hydrogen silane or triethoxy hydrogen silane; the added amount of the trialkoxy hydrogen silane is 5% to 15% of the mass of the vinyl modified reinforcing filler.

[0023] Furthermore, the weight average molecular weight of the hydroxy silicone oil is 0.5 to 50,000.

[0024] Furthermore, the vulcanizing agent is dicumyl peroxide, benzoyl peroxide, tert-butyl peracetate or tert-butyl perbenzoate.

[0025] Furthermore, the accelerator is tetramethylthiuram disulfide (TMTD).

[0026] The silicone rubber composition obtained by the present invention has a tensile strength of >8.5MPa, an elongation at break of >250%, and a tear strength of >30kN / m after vulcanization, and meets the performance requirements of silicone rubber compound for wires and cables (GB / T 33430-2016).

[0027] The preparation method of the silicone rubber composition comprises the following steps:

[0028] The methyl vinyl silicone rubber and hydroxy silicone oil are mixed evenly in an atmosphere-protected internal mixer, and then vinyl-modified reinforcing filler, alkoxy-modified reinforcing filler, vulcanizing agent and accelerator are added and mixed evenly to obtain a silicone rubber composition.

[0029] A high-strength weather-resistant silicone rubber wire and cable comprises a metal core (such as a copper core, an aluminum core, etc.), an insulating layer (such as PVC, XLPE, etc.), a glass fiber cloth layer and a silicone rubber protective layer which are sequentially distributed from the inside to the outside; the silicone rubber protective layer is obtained by coating and then vulcanizing the above silicone rubber composition.

[0030] The preparation method of the above-mentioned high-strength weather-resistant silicone rubber wire and cable comprises the following preparation steps:

[0031] (1) preparing an insulating layer on the outside of the metal core by an extrusion process, and then weaving a glass fiber cloth layer on the outside of the insulating layer;

[0032] (2) The silicone rubber composition is used to prepare a silicone rubber layer on the outside of the glass fiber cloth layer through an extrusion process, and a silicone rubber protective layer is obtained after heating and vulcanization treatment.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The silicone rubber composition of the present invention uses a vinyl-modified reinforcing filler, which, on the one hand, improves the dispersion effect of the reinforcing filler in the silicone rubber matrix; on the other hand, it can undergo a vulcanization cross-linking reaction with methyl vinyl silicone rubber, significantly improving the reinforcing effect and improving the defect of insufficient strength of the silicone rubber.

[0035] (2) The silicone rubber composition of the present invention uses an alkoxy-modified reinforcing filler. On the one hand, the alkoxy-modified reinforcing filler can undergo hydrolysis and dealcoholization with the moisture contained on the surface of the glass fiber cloth layer and undergo coupling reaction with the surface of the glass fiber cloth layer, thereby significantly improving the bonding force between the silicone rubber and the glass fiber cloth and improving the composite strength. On the other hand, the alkoxy-modified reinforcing filler can be further subjected to dealcoholization condensation cross-linking with hydroxy silicone oil to obtain a cross-linked network structure with the reinforcing filler as the center and long-chain Si-O-Si chains as bridges, thereby significantly improving the strength, toughness and weather resistance of the silicone rubber protective layer. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0037] Example 1

[0038] A method for preparing a high-strength weather-resistant silicone rubber wire and cable comprises the following preparation steps:

[0039] (1) A PVC insulation layer is prepared on the outside of the copper core by an extrusion process, and then a glass fiber cloth layer is woven on the outside of the insulation layer.

[0040] (2) A silicone rubber layer is prepared on the outside of the glass fiber cloth layer by using a silicone rubber composition through an extrusion process, and a silicone rubber protective layer is obtained after a heating and vulcanization treatment at 170-180° C.

[0041] The silicone rubber composition described in this embodiment is prepared by the following method:

[0042] By weight, 80 parts of methyl vinyl silicone rubber (vinyl content of 0.25%, weight average molecular weight of 500,000) and 20 parts of hydroxy silicone oil (weight average molecular weight of 20,000) are mixed evenly in a nitrogen-protected internal mixer, and then 20 parts of vinyl-modified reinforcing filler, 20 parts of alkoxy-modified reinforcing filler, 1.5 parts of vulcanizing agent diisopropylbenzene peroxide and 0.8 parts of accelerator TMTD are added and mixed evenly to obtain a silicone rubber composition.

[0043] The vinyl modified reinforcing filler described in this embodiment is white carbon black modified by a vinyl silane coupling agent, which is prepared by the following method:

[0044] The silica was added into isopropanol solvent and dispersed evenly, and then 10% of the mass of the silica was added with vinyl triethoxysilane, and the temperature was raised to 45°C under normal air conditions and stirred for reaction for 1 hour, and vacuum spray dried at 80°C to obtain vinyl modified silica.

[0045] The alkoxy-modified reinforcing filler described in this embodiment is ethoxy-modified white carbon black, which is prepared by the following method:

[0046] The above-mentioned vinyl-modified silica was added to isopropanol solvent and dispersed evenly. The temperature was raised to 80°C under nitrogen protection, and then triethoxyhydrosilane accounting for 10% of the mass of the vinyl-modified silica and 100ppm of chloroplatinic acid catalyst were added and stirred for 3h. The mixture was vacuum spray-dried at 80°C to obtain ethoxy-modified silica.

[0047] Example 2

[0048] A method for preparing a high-strength weather-resistant silicone rubber wire and cable comprises the following preparation steps:

[0049] (1) A PVC insulation layer is prepared on the outside of the copper core by an extrusion process, and then a glass fiber cloth layer is woven on the outside of the insulation layer.

[0050] (2) A silicone rubber layer is prepared on the outside of the glass fiber cloth layer by using a silicone rubber composition through an extrusion process, and a silicone rubber protective layer is obtained after a heating and vulcanization treatment at 170-180° C.

[0051] The silicone rubber composition described in this embodiment is prepared by the following method:

[0052] By weight, 60 parts of methyl vinyl silicone rubber (vinyl content of 0.25%, weight average molecular weight of 500,000) and 10 parts of hydroxy silicone oil (weight average molecular weight of 20,000) are mixed evenly in a nitrogen-protected internal mixer, and then 10 parts of vinyl-modified reinforcing fillers, 10 parts of alkoxy-modified reinforcing fillers, 1 part of vulcanizing agent diisopropylbenzene peroxide and 0.5 parts of accelerator TMTD are added and mixed evenly to obtain a silicone rubber composition.

[0053] The vinyl modified reinforcing filler described in this embodiment is white carbon black modified by a vinyl silane coupling agent, which is prepared by the following method:

[0054] Add silica to isopropanol solvent and disperse it evenly, then add vinyltrimethoxysilane accounting for 5% of the mass of silica, heat to 45°C under normal air conditions, stir and react for 1 hour, and vacuum spray dry at 80°C to obtain vinyl-modified silica.

[0055] The alkoxy-modified reinforcing filler described in this embodiment is methoxy-modified white carbon black, which is prepared by the following method:

[0056] The above-mentioned vinyl-modified silica was added into isopropanol solvent and dispersed evenly. The temperature was raised to 80°C under nitrogen protection. Then, trimethoxyhydrosilane accounting for 5% of the mass of the vinyl-modified silica and 100ppm of chloroplatinic acid catalyst were added and stirred for 3h. The mixture was vacuum spray-dried at 80°C to obtain methoxy-modified silica.

[0057] Example 3

[0058] A method for preparing a high-strength weather-resistant silicone rubber wire and cable comprises the following preparation steps:

[0059] (1) An XLPE insulation layer is prepared on the outside of the aluminum core by an extrusion process, and then a glass fiber cloth layer is woven on the outside of the insulation layer.

[0060] (2) A silicone rubber layer is prepared on the outside of the glass fiber cloth layer by using a silicone rubber composition through an extrusion process, and a silicone rubber protective layer is obtained after a heating and vulcanization treatment at 170-180° C.

[0061] The silicone rubber composition described in this embodiment is prepared by the following method:

[0062] By weight, 100 parts of methyl vinyl silicone rubber (vinyl content of 0.25%, weight average molecular weight of 500,000) and 30 parts of hydroxy silicone oil (weight average molecular weight of 20,000) are mixed evenly in a nitrogen-protected internal mixer, and then 30 parts of vinyl-modified reinforcing fillers, 30 parts of alkoxy-modified reinforcing fillers, 3 parts of vulcanizing agent diisopropylbenzene peroxide and 1 part of accelerator TMTD are added and mixed evenly to obtain a silicone rubber composition.

[0063] The vinyl modified reinforcing filler described in this embodiment is white carbon black modified by a vinyl silane coupling agent, which is prepared by the following method:

[0064] Add silica to isopropanol solvent and disperse it evenly, then add vinyl triethoxysilane accounting for 15% of the mass of silica, heat to 45°C under normal air conditions, stir and react for 1 hour, and vacuum spray dry at 80°C to obtain vinyl modified silica.

[0065] The alkoxy-modified reinforcing filler described in this embodiment is ethoxy-modified white carbon black, which is prepared by the following method:

[0066] The above-mentioned vinyl-modified silica was added to isopropanol solvent and dispersed evenly. The temperature was raised to 80°C under nitrogen protection, and then triethoxyhydrosilane accounting for 15% of the mass of the vinyl-modified silica and 100ppm of chloroplatinic acid catalyst were added and stirred for 3h. The mixture was vacuum spray-dried at 80°C to obtain ethoxy-modified silica.

[0067] Comparative Example 1

[0068] A silicone rubber composition, compared with Example 1, no vinyl modified reinforcing filler is added, the amount of alkoxy modified reinforcing filler added is increased to 40 parts, and the rest is the same.

[0069] Comparative Example 2

[0070] A silicone rubber composition, compared with Example 1, does not contain alkoxy modified reinforcing filler, increases the amount of vinyl modified reinforcing filler added to 40 parts, and remains the same.

[0071] Comparative Example 3

[0072] A silicone rubber composition, compared with Example 1, without adding hydroxy silicone oil, and the rest is the same.

[0073] The tensile strength, elongation at break, tensile strength and elongation at break after hot air aging, tear strength and tensile shear strength after composite with glass fiber cloth layer of the silicone rubber compositions obtained in the above Examples 1 to 3 and Comparative Examples 1 to 3 were tested (testing with reference to GB / T 33430-2016), and the results are shown in Table 1 below.

[0074] Table 1

[0075]

[0076] From the comparison results of Comparative Example 1 and Examples 1 to 3 in Table 1, it can be seen that the present invention can significantly improve the strength and weather resistance of silicone rubber by adding vinyl modified reinforcing filler. From the comparison results of Comparative Example 2 and Examples 1 to 3, it can be seen that the present invention can significantly improve the toughness and weather resistance of silicone rubber and significantly improve the bonding force with the glass fiber cloth layer by adding alkoxy modified reinforcing filler. From the comparison results of Comparative Example 3 and Examples 1 to 3, it can be seen that the present invention can significantly improve the strength, toughness and weather resistance of high silicone rubber by adding hydroxy silicone oil and utilizing its cross-linking reaction with alkoxy modified reinforcing filler.

[0077] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A silicone rubber composition, characterized in that: The composition comprises the following components in parts by weight: 60~100 parts of methyl vinyl silicone rubber; 10-30 parts of vinyl modified reinforcing filler; 10-30 parts of alkoxy modified reinforcing filler; 10-30 parts of hydroxy silicone oil; 1~3 parts of vulcanizing agent; Accelerator 0.5~1 part; The preparation method of the vinyl modified reinforcing filler is: The reinforcing filler is added to the organic solvent and dispersed evenly, and then a vinyl silane coupling agent is added, and the temperature is raised to 30-60° C. under normal air conditions, and the mixture is stirred for reaction for 0.5-2 hours, and vacuum spray-dried to obtain a vinyl-modified reinforcing filler; the vinyl silane coupling agent is selected from vinyl trimethoxysilane or vinyl triethoxysilane; and the amount of the vinyl silane coupling agent added is 5%-15% of the mass of the reinforcing filler; The preparation method of the alkoxy modified reinforcing filler is: The vinyl modified reinforcing filler is added to an organic solvent and dispersed evenly, and the temperature is raised to 60-100° C. under nitrogen protection conditions, and then trialkoxy hydrogen silane and chloroplatinic acid catalyst are added and stirred to react for 2-4 hours, and vacuum spray drying is performed to obtain an alkoxy modified reinforcing filler; the trialkoxy hydrogen silane is selected from trimethoxy hydrogen silane or triethoxy hydrogen silane; and the amount of trialkoxy hydrogen silane added is 5%-15% of the mass of the vinyl modified reinforcing filler.

2. A silicone rubber composition according to claim 1, characterized in that: The vinyl content of the methyl vinyl silicone rubber is 0.05% to 0.5%, and the weight average molecular weight is 300,000 to 700,000.

3. A silicone rubber composition according to claim 1, characterized in that: The reinforcing filler is selected from at least one of silicon dioxide, aluminum hydroxide and magnesium hydroxide.

4. A silicone rubber composition according to claim 1, characterized in that: The weight average molecular weight of the hydroxy silicone oil is 0.5-50,000; the vulcanizing agent is dicumyl peroxide, benzoyl peroxide, tert-butyl peracetate or tert-butyl perbenzoate; and the accelerator is tetramethylthiuram disulfide.

5. A silicone rubber composition according to any one of claims 1 to 4, characterized in that: The silicone rubber composition after vulcanization has a tensile strength greater than 8.5 MPa, an elongation at break greater than 250%, and a tear strength greater than 30 kN / m.

6. The method for preparing a silicone rubber composition according to any one of claims 1 to 5, characterized in that: The steps include: The methyl vinyl silicone rubber and hydroxy silicone oil are mixed evenly in an atmosphere-protected internal mixer, and then vinyl-modified reinforcing filler, alkoxy-modified reinforcing filler, vulcanizing agent and accelerator are added and mixed evenly to obtain a silicone rubber composition.

7. A high-strength weather-resistant silicone rubber wire and cable, characterized in that: It comprises a metal core, an insulating layer, a glass fiber cloth layer and a silicone rubber protective layer which are sequentially distributed from the inside to the outside; the silicone rubber protective layer is obtained by coating and then vulcanizing the silicone rubber composition according to any one of claims 1 to 5.

8. The method for preparing a high-strength weather-resistant silicone rubber wire and cable according to claim 7, characterized in that: The method comprises the following preparation steps: (1) An insulating layer is prepared on the outside of the metal core by an extrusion process, and then a glass fiber cloth layer is woven on the outside of the insulating layer; (2) A silicone rubber layer is prepared on the outside of the glass fiber cloth layer by using the silicone rubber composition according to any one of claims 1 to 5 through an extrusion process, and a silicone rubber protective layer is obtained after a heating and vulcanization treatment.

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