Silicone rubber wire and preparation method thereof
By forming a silicone rubber layer containing micropores on the outer layer of the conductor of the silicone rubber wire, the problem of high production cost of silicone rubber wire is solved, and the effect of performance optimization and cost reduction is achieved.
Patent Information
- Application Number
- CN202311000303.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-08-09
- Publication Date
- 2025-02-18
AI Technical Summary
The production cost of existing silicone rubber wires is relatively high, mainly due to the high price of silicone rubber and the complex production process.
By forming a micropore-containing silicone rubber layer on the outer layer of the conductor, forming micropores with foaming agent and glass microbeads, the density and weight of the silicone rubber layer are reduced, thereby reducing the amount of raw material and production costs.
The performance optimization of silicone rubber wires is achieved, including good tensile strength, toughness and flame retardant grades, while reducing production costs, and reducing the weight of the silicone rubber layer by 10% to 50%.
Smart Images
Figure CN119480219A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of electric wires, and in particular to a silicone rubber electric wire and a preparation method thereof. Background Art
[0002] Silicone rubber wire has excellent high temperature resistance, excellent electrical insulation performance, excellent chemical stability, high voltage resistance, aging resistance, long service life, soft and easy to install.
[0003] Since silicone rubber is expensive and the production process of silicone rubber wires is complicated, the production cost of silicone rubber wires is higher than that of high-temperature resistant wires made of other materials. Therefore, it is necessary to develop a new silicone rubber wire and a preparation method thereof. Summary of the invention
[0004] An embodiment of the present disclosure provides a silicone rubber wire, comprising: a conductor, the silicone rubber wire further comprising: a silicone rubber layer wrapped around the outer circumference of the conductor, the silicone rubber layer comprising a plurality of micropores, and the pore diameter of the micropores is 10 to 250 μm.
[0005] In some embodiments, the micropores include first micropores, the first micropores are formed by foaming a foaming agent, and the pore diameter of the first micropores is 10 to 250 μm.
[0006] In some embodiments, the pore size of the first micropores is 15-150 μm.
[0007] In some embodiments, the blowing agent is an expanded microsphere blowing agent.
[0008] In some embodiments, the micropores further include second micropores, the second micropores are formed by glass microbeads, and the pore diameter of the second micropores is 10-100 μm.
[0009] In some embodiments, the tensile strength of the silicone rubber layer is 0.5-5 MPa.
[0010] In some embodiments, the elongation at break of the silicone rubber layer is 200% to 800%.
[0011] In some embodiments, the flame retardant grade of the silicone rubber layer is V2-V0.
[0012] In some embodiments, the thickness of the silicone rubber layer is 0.3-2 mm.
[0013] In some embodiments, the density of the silicone rubber layer is 0.5-1.0 g / cm 3 .
[0014] In some embodiments, the silicone rubber wire further includes: a shielding layer, located between the silicone rubber layer and the conductor, and wrapped around the outer circumference of the conductor.
[0015] In some embodiments, the shielding layer is made of aluminum foil.
[0016] An embodiment of the present disclosure also provides a method for preparing a silicone rubber wire, the preparation method comprising: mixing raw materials including initial silicone rubber, a flame retardant, a pore-forming agent and a cross-linking agent to obtain a rubber mixture; coating the rubber mixture on a conductor; heating the conductor coated with the rubber mixture to foam and vulcanize the rubber mixture to form a silicone rubber layer, wherein the pore-forming agent is used to form a plurality of micropores, the plurality of micropores are distributed in the silicone rubber layer, and the pore diameter of the micropores is 10 to 250 μm.
[0017] In some embodiments, the pore former includes a foaming agent, and the mass fraction of the foaming agent in the raw material is 0.1% to 0.5%.
[0018] In some embodiments, the foaming agent is used to form first micropores, and the pore diameter of the first micropores is 10 to 250 μm.
[0019] In some embodiments, the foaming agent is an expandable microsphere foaming agent, the particle size of the foaming agent is 5 to 50 μm, and the expansion ratio of the foaming agent is 2 to 5 times.
[0020] In some embodiments, the thickness of the silicone rubber on the conductor after foaming increases by 20% to 200% compared with that before foaming.
[0021] In some embodiments, the initial silicone rubber includes: one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber and methyl vinyl trifluoropropyl silicone rubber; the mass fraction of the initial silicone rubber in the raw material is 57.5% to 93.4%.
[0022] In some embodiments, the mass fraction of the flame retardant in the raw material is 5% to 35%; the flame retardant includes: one or more of aluminum hydroxide, magnesium hydroxide and zinc borate.
[0023] In some embodiments, the mass fraction of the cross-linking agent in the raw material is 0.5% to 2%; the cross-linking agent includes: one or more of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide and platinum vulcanizing agent.
[0024] In some embodiments, the mixing includes a first mixing, which includes: adding the initial silicone rubber, flame retardant and cross-linking agent into an internal mixer and mixing for 1 minute to 3 minutes, then adding the pore-forming agent into the internal mixer and mixing for 3 to 5 minutes to obtain a first mixing product; the mixing temperature of the first mixing is not higher than 50°C.
[0025] In some embodiments, the pore former further comprises: glass microspheres, and the mass fraction of the glass microspheres in the raw material is 1% to 5%.
[0026] In some embodiments, the glass microbeads have a particle size of 10-100 μm, and the glass microbeads are used to form second micropores distributed in the silicone rubber layer.
[0027] In some embodiments, the mixing also includes a second mixing, and the second mixing includes: adding the first mixing product to an open mill and mixing for 3 to 5 minutes to obtain a mixed rubber; the mixing temperature used in the second mixing is not higher than 50°C, and the roller spacing of the open mill is 5 to 15 mm.
[0028] In some embodiments, the heating temperature is 120° C. to 170° C., the length of the heated drying tunnel is 20 to 40 m, and the moving speed of the conductor coated with the rubber compound in the drying tunnel is 1 to 10 m / min.
[0029] In some embodiments, before coating the rubber compound on the conductor, a shielding layer is first formed on the conductor, and the shielding layer wraps the conductor.
[0030] Compared with the prior art, the technical solution of the embodiment of the present disclosure has the following beneficial effects:
[0031] The silicone rubber layer of the silicone rubber wire of the embodiment of the present disclosure includes a plurality of micropores, the pore size of the micropores is 10 to 250 μm, and the pore size of the micropores is controlled within a specific range, so that the performance of the silicone rubber layer is not affected by the micropores. At the same time, the plurality of micropores makes the weight of the silicone rubber layer 10% to 50% lighter than when there are no micropores, thereby reducing the initial amount of silicone rubber used and saving the production cost of raw materials and silicone rubber wires.
[0032] The silicone rubber wire prepared by the preparation method of the silicone rubber wire in the embodiment of the present disclosure has an outermost silicone rubber layer of the conductor that is prepared from a raw material including a foaming agent with a mass fraction of 0.1% to 0.5%. The silicone rubber layer has good tensile strength, toughness and flame retardancy, which can meet the use requirements of the silicone rubber wire, and at the same time has a lighter weight, reduces the amount of initial silicone rubber raw materials used, and saves costs.
[0033] The silicone rubber wire prepared by the method for preparing the silicone rubber wire of the embodiment of the present disclosure has a silicone rubber layer as the outermost layer of the conductor, which is prepared from raw materials including a foaming agent with a mass fraction of 0.1% to 0.5% and glass microbeads with a mass fraction of 1% to 5%. The glass microbeads are beneficial to the dispersion and uniform distribution of micropores in the silicone rubber layer. Without affecting the mechanical properties of the silicone rubber layer, the glass microbeads further reduce the weight of the silicone rubber layer. The silicone rubber layer has good tensile strength, toughness and flame retardant grade, which can meet the use requirements of silicone rubber wires, and at the same time has a lighter weight, reduces the amount of initial silicone rubber, and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0034] Other features and advantages of the present disclosure will be better understood through the following detailed description of the optional embodiments in conjunction with the accompanying drawings, in which the same reference numerals represent the same or similar components, wherein:
[0035] Figure 1-Figure 2 A schematic cross-sectional view of a silicone rubber wire according to an embodiment of the present disclosure is shown;
[0036] Figure 3-Figure 5 A schematic diagram showing a process of a method for preparing a silicone rubber wire according to an embodiment of the present disclosure is shown;
[0037] Figure 6-Figure 8 A scanning electron microscope image of a cross section of a silicone rubber layer of a silicone rubber wire 1# according to Example 1 of a specific embodiment of the present disclosure is shown;
[0038] Figure 9-12 A scanning electron microscope image of a cross section of a silicone rubber layer of a silicone rubber wire 2# according to Example 2 of a specific embodiment of the present disclosure is shown;
[0039] Fig.13 Photos of silicone rubber wire 2# of Example 2 and silicone rubber wire 3# of Comparative Example 1 are shown according to a specific embodiment of the present disclosure. DETAILED DESCRIPTION
[0040] Embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. In the accompanying drawings, the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present disclosure, and cannot be understood as limiting the present disclosure.
[0041] In order to save silicone rubber raw materials and reduce the production cost of silicone rubber wires, embodiments of the present disclosure provide a new silicone rubber wire and a preparation method thereof.
[0042] Figure 1-Figure 2 FIG. 2 shows a schematic cross-sectional view of a silicone rubber wire according to an embodiment of the present disclosure. Figure 1 and Figure 2 The silicone rubber wire according to the embodiment of the present disclosure is described in detail.
[0043] refer to Figure 1 The silicone rubber wire of the embodiment of the present disclosure includes: a conductor 1, and a silicone rubber layer 2 wrapped around the outer periphery of the conductor 1. In some embodiments, the silicone rubber layer 2 is directly wrapped around the outer periphery of the conductor 1; in some embodiments, the silicone rubber layer 2 is directly wrapped around the outer periphery of the conductor 1.
[0044] The silicone rubber layer 2 includes a plurality of micropores, and the pore diameter of the micropores is 10 to 250 μm. To more accurately represent the size of the micropores, the pore diameter refers to the average pore diameter of the micropores, that is, since the shape of a single micropore may be asymmetric, its pore diameter is the average value of the pore diameters in multiple directions.
[0045] In some embodiments, the silicone rubber layer 2 is prepared from raw materials including initial silicone rubber, flame retardant, foaming agent and cross-linking agent. According to the performance requirements of the silicone rubber layer 2 in actual applications, a suitable foaming agent is selected and a suitable amount of foaming agent is added. In some embodiments, the mass fraction of the foaming agent in the raw material is 0.1% to 0.5%.
[0046] In some embodiments, the foaming agent is an expandable microsphere foaming agent, which is suitable for expanding under heat to form a hollow structure, and the particle size of the expandable microsphere foaming agent is 5 to 50 μm; in some embodiments, the particle size of the microsphere foaming agent after foaming is 2 to 5 times that before foaming. In some embodiments, the expandable microsphere foaming agent is a core-shell structure, the core is a spherical plastic particle composed of alkane gas, and the shell is a thermoplastic acrylic polymer.
[0047] In some embodiments, the foaming agent is azodicarbonamide (AC), azobisisobutyronitrile (AIBN), or 4,4-oxobissulfonylhydrazide (OBSH); in some embodiments, the foaming agent is a mixture of urea lipid BK and N,N'-dinitrosopentamethylenetetramine.
[0048] In some embodiments, the micropores include first micropores, which are formed by foaming the foaming agent. In order to ensure that the performance of the silicone rubber layer 2 is not affected by the micropores and avoid affecting the use of the silicone rubber wires, the pore size of the first micropores needs to be controlled within a specific range. In some embodiments, the pore size of the first micropores is 10 to 250 μm; further, the pore size of the first micropores is 15 to 150 μm.
[0049] In some embodiments, the raw materials for preparing the silicone rubber layer 2 include glass microspheres in addition to the initial silicone rubber, flame retardant, foaming agent and crosslinking agent. The glass microspheres are hollow structures, that is, the glass microspheres include microsphere walls, and the microsphere walls are hollow.
[0050] Glass microbeads help reduce the weight of the silicone rubber layer 2, but they make the silicone rubber layer 2 hard and brittle, affecting the elongation at break of the silicone rubber layer 2. In order to meet the performance requirements of the silicone rubber layer 2, it is necessary to control the amount of glass microbeads used. In some embodiments, the mass fraction of the glass microbeads in the preparation raw materials is 1% to 5%. In some embodiments, the particle size of the glass microbeads is 10 to 100 μm, and the particle size of the glass microbeads hardly changes before and after heating.
[0051] In some embodiments, the micropores also include second micropores, that is, a plurality of first micropores and a plurality of second micropores form a plurality of micropores, and the second micropores are formed by the glass beads. In order to ensure that the performance of the silicone rubber layer 2 is not affected by the micropores and avoid affecting the use of the silicone rubber wires, the pore size of the second micropores needs to be controlled within a specific range. In some embodiments, the pore size of the second micropores is 10 to 100 μm.
[0052] In some embodiments, the flame retardant in the raw material for preparing the silicone rubber layer 2 includes: one or more of aluminum hydroxide, magnesium hydroxide, or zinc borate. In some embodiments, the flame retardant is zinc borate and hydroxide, wherein the mass fraction of zinc borate in the raw material for preparing the silicone rubber layer 2 is 3-8%, and the mass fraction of hydroxide in the raw material for preparing the silicone rubber layer 2 is 17-32%.
[0053] In some embodiments, the mass fraction of the flame retardant in the raw materials for preparing the silicone rubber layer 2 is 5% to 35%.
[0054] In some embodiments, the crosslinking agent in the raw materials for preparing the silicone rubber layer 2 includes one or more of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide and platinum vulcanizer.
[0055] In some embodiments, the mass fraction of the cross-linking agent in the raw materials for preparing the silicone rubber layer 2 is 0.5% to 2%.
[0056] In the raw materials used for preparing the silicone rubber layer 2 of the embodiment of the present disclosure, the initial silicone rubber includes: one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber and methyl vinyl trifluoropropyl silicone rubber.
[0057] In some embodiments, the mass fraction of the initial silicone rubber in the preparation raw materials is 57.5% to 93.4%.
[0058] The silicone rubber wire of the embodiment of the present disclosure, the silicone rubber layer 2 can replace the silicone rubber layer of the existing conventional silicone rubber wire with the same thickness, and the silicone rubber layer 2 of the embodiment of the present disclosure has micropores with a hollow structure, so the silicone rubber layer 2 has a lighter weight, and the amount of initial silicone rubber used in preparing the silicone rubber layer 2 is less, which saves raw materials and reduces the production cost of the silicone rubber wire.
[0059] In some embodiments, the weight of the silicone rubber layer 2 with the same thickness is reduced by 10% to 50% compared with the silicone rubber layer of a conventional silicone rubber wire.
[0060] In some embodiments, the thickness of the silicone rubber layer 2 is 0.3-2 mm; in some embodiments, the thickness of the silicone rubber layer 2 is 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2 mm, etc.
[0061] The silicone rubber wire of the embodiment of the present disclosure has a silicone rubber layer 2 with good tensile strength, toughness and flame retardant properties. The silicone rubber layer 2 can be used as the outermost layer of the silicone rubber wire, directly or indirectly wrapping the conductor to protect the conductor, flame retardant and insulating.
[0062] In some embodiments, according to the test of "GB / T1040 Determination of Tensile Properties of Plastics", the tensile strength of the silicone rubber layer 2 is 0.5-5 MPa.
[0063] In some embodiments, the elongation at break of the silicone rubber layer 2 is 200% to 800% when tested according to GB / T1040 Determination of tensile properties of plastics.
[0064] In some embodiments, according to the UL94 standard, the flame retardancy rating of the silicone rubber layer 2 is V2-V0; further, the flame retardancy rating of the silicone rubber layer 2 is above V1; further, the flame retardancy rating of the silicone rubber layer 2 is V0.
[0065] In the silicone rubber wire of the embodiment of the present disclosure, the conductor 1 may be a single-core or multi-core conductive wire core, and the silicone rubber layer 2 of the embodiment of the present disclosure is suitable for protecting various conductors that can be used for wires.
[0066] The silicone rubber wire of the embodiment of the present disclosure can be applied to power transmission under multiple voltage conditions, for example, power transmission within 600V or within 3000V.
[0067] The silicone rubber wires of the embodiments of the present disclosure can be applied to multiple fields, such as ordinary civilian wires, automotive cables, industrial cables, etc.
[0068] refer to Figure 2 The silicone rubber wire of the embodiment of the present disclosure includes: a conductor 1, a silicone rubber layer 2, and a shielding layer 3 located between the silicone rubber layer 2 and the conductor 1. The shielding layer 3 is directly wrapped around the outer periphery of the conductor 1 to shield the external electromagnetic interference to the conductor 1 during the use of the silicone rubber wire.
[0069] In some embodiments, the shielding layer 3 is composed of one or more metals. For example, the shielding layer 3 is made of aluminum foil.
[0070] In some embodiments, the shielding layer 3 has a thickness of 50-100 μm.
[0071] The silicone rubber wire having the silicone rubber layer 2 and the shielding layer 3 according to the embodiment of the present disclosure can be applied to the fields of ordinary civilian wires, automotive cables, industrial cables, etc.
[0072] The silicone rubber wire with a silicone rubber layer 2 and a shielding layer 3 according to the embodiment of the present disclosure can be used in electric vehicles, especially for the electrical connection between a power battery and a control system and between a control system and a motor. The shielding layer 3 has a shielding effect, which can prevent the signal transmitted by the silicone rubber wire from being electromagnetically interfered.
[0073] It should be noted that the silicone rubber wire provided in the embodiment of the present disclosure has a silicone rubber layer as the outermost layer, which can be wrapped around the conductor. In some embodiments, one or more other layers, such as a shielding layer, a braided layer, etc., can be provided between the silicone rubber layer and the conductor.
[0074] An embodiment of the present disclosure also provides a method for preparing a silicone rubber wire, the preparation method comprising: mixing raw materials including initial silicone rubber, a flame retardant, a foaming agent and a cross-linking agent to obtain a rubber mixture, wherein the mass fraction of the foaming agent in the raw materials is 0.1% to 0.5%; coating the rubber mixture on a conductor; heating the conductor coated with the rubber mixture to foam and vulcanize the rubber mixture coated on the conductor.
[0075] refer to Figure 3 , Figure 3 The schematic diagram of the process of preparing the silicone rubber wire according to the embodiment of the present disclosure is shown. The method of preparing the silicone rubber wire according to the embodiment of the present disclosure includes the following process.
[0076] In S11, raw materials including initial silicone rubber, flame retardant, pore former and crosslinking agent are mixed to obtain a mixed rubber; the pore former is used to form a plurality of micropores distributed in the silicone rubber layer, and the pore diameter of the micropores is 10 to 250 μm.
[0077] In some embodiments, the pore former includes a foaming agent, the foaming agent is used to form the first micropores, and the mass fraction of the foaming agent in the raw material is 0.1% to 0.5%.
[0078] In some embodiments, controlling the amount of the foaming agent added within a specific range helps control the number and pore size of the first micropores formed by the foaming agent, so that the silicone rubber layer has both a lighter weight and good performance.
[0079] In some embodiments, the foaming agent is an expanded microsphere foaming agent, the particle size of the foaming agent is 5 to 50 μm, the expansion ratio of the foaming agent is 2 to 5 times, and the foaming agent expands during subsequent heating to form first micropores distributed in the prepared silicone rubber layer. In some embodiments, the pore size of the first micropores is 10 to 250 μm.
[0080] In some embodiments, the initial silicone rubber includes: one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber and methyl vinyl trifluoropropyl silicone rubber. In some embodiments, the mass fraction of the initial silicone rubber in the raw material is 57.5% to 93.4%.
[0081] In some embodiments, the flame retardant includes: one or more of aluminum hydroxide, magnesium hydroxide and zinc borate.
[0082] By changing the amount of flame retardant added, the prepared silicone rubber has good flame retardant properties. In some embodiments, the mass fraction of the flame retardant in the raw material is 5% to 35%; in some embodiments, the mass fraction of the flame retardant in the raw material is 10% to 35%; in some embodiments, the mass fraction of the flame retardant in the raw material is 15% to 25%. In some embodiments, the flame retardant is zinc borate and hydroxide, the mass fraction of zinc borate in the raw material is 3 to 8%, and the mass fraction of hydroxide in the raw material is 17 to 32%.
[0083] In some embodiments, the cross-linking agent includes one or more of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, dicumyl peroxide and platinum vulcanizing agent.
[0084] In some embodiments, the mass fraction of the cross-linking agent in the raw material is 0.5% to 2%.
[0085] In some embodiments, in order to make the first micropores in the silicone rubber layer more evenly distributed, the pore-forming agent also includes glass microspheres, which are hollow structures. The size of the glass microspheres remains almost unchanged after being heated. The glass microspheres are used to form second micropores, which are distributed in the silicone rubber layer. In order to ensure that the glass microspheres do not affect the performance of the silicone rubber layer, it is necessary to control the amount of glass microspheres added and the particle size of the glass microspheres. In some embodiments, the mass fraction of the glass microspheres in the raw materials is 1% to 5%, in some embodiments, the particle size of the glass microspheres is 10 to 100 μm, and in some embodiments, the particle size of the glass microspheres is 30 to 100 μm. At the same time, when the amount of the foaming agent added is controlled within a specific range, the addition of glass microspheres can further reduce the weight of the prepared silicone rubber layer.
[0086] The use of glass micro-beads can enable the prepared silicone rubber layer to form a structure with a plurality of gaps, and the size of the glass micro-beads does not change during subsequent heating.
[0087] After mixing, the components in the raw materials, such as the initial silicone rubber, flame retardant, pore former and cross-linking agent, are evenly distributed in the initial silicone rubber, so as to facilitate the foaming of the foaming agent included in the pore former during subsequent heating to form a uniformly distributed hollow microporous structure in the prepared silicone rubber layer, and to facilitate the vulcanization of the initial silicone rubber.
[0088] In some embodiments, after mixing, the components of the raw materials, namely the initial silicone rubber, flame retardant, cross-linking agent, foaming agent and glass microbeads, are evenly distributed in the initial silicone rubber, so that during subsequent heating, the hollow microporous structure formed by the foaming of the foaming agent and the hollow glass microbeads are evenly distributed in the prepared silicone rubber layer, so as to facilitate the vulcanization of the initial silicone rubber.
[0089] In some embodiments, the particle size and amount of the foaming agent and the glass microbeads can be adjusted according to the performance requirements of the silicone rubber layer of the silicone rubber wire to be prepared in actual need.
[0090] In some embodiments, in order to meet the color requirements for silicone rubber wires, pigments of specific colors are added and mixed with the raw materials so that the obtained mixed rubber has a specific color.
[0091] In S12, the rubber compound is applied on the conductor.
[0092] In some embodiments, the rubber mix is applied to the conductor by an extruder. Specifically, the rubber mix is added to the conductor main body, the conductor passes through the extruder die, and the rubber mix is extruded and applied to the conductor by a screw extruder. The conductor movement speed is controlled to be compatible with the rubber mix extrusion speed so that the rubber mix is evenly applied to the conductor.
[0093] The conductor 1 can be a single-core or multi-core wire. The rubber compound is suitable for coating on various conductors that can be used for electric wires, and finally forms a silicone rubber layer to protect the conductor.
[0094] In S13 , the conductor coated with the rubber compound is heated to foam and vulcanize the rubber compound to form a silicone rubber layer.
[0095] In some embodiments, the heating is performed in a drying tunnel, the temperature of the drying tunnel is 120° C. to 170° C., and the length of the drying tunnel is 20 to 40 m. The conductor coated with the rubber mix is moved in the drying tunnel by a traction device to foam and vulcanize the rubber mix, the foaming agent expands when heated, and the cross-linking agent promotes the vulcanization reaction between the initial silicone rubbers when heated, thereby forming a silicone rubber layer.
[0096] The silicone rubber layer includes first micropores formed by a foaming agent, and the first micropores are distributed in the silicone rubber layer. To ensure the performance of the silicone rubber layer, the pore size of the first micropores is controlled within a specific range. In some embodiments, the pore size of the first micropores is 10 to 250 μm; in some embodiments, the pore size of the first micropores is 10 to 150 μm; in some embodiments, the pore size of the first micropores is 70 to 150 μm; in some embodiments, the pore size of the first micropores is 100 to 150 μm.
[0097] In some embodiments, the plurality of micropores in the silicone rubber layer include first micropores and second micropores. The second micropores are formed by glass microbeads. To ensure the performance of the silicone rubber layer, the pore size of the second micropores is controlled within a specific range. In some embodiments, the pore size of the second micropores is 10 to 100 μm; in some embodiments, the pore size of the second micropores is 30 to 100 μm.
[0098] The temperature of the drying oven and the residence time of the rubber mix at different temperatures affect the foaming and vulcanization process and the performance of the silicone rubber finally formed. If the temperature is too low, the vulcanization rate will be slow, resulting in reduced production efficiency of silicone rubber wires. If the temperature is too high, the foaming will be uneven or insufficient, affecting the performance of silicone rubber wires. The embodiment of the present disclosure uses a traction device to move the conductor coated with the rubber mix in the drying oven at a speed of 1 to 10 m / min. The speed can be variable or uniform to adjust the residence time of the conductor coated with the rubber mix in the heating section of the drying oven at different temperatures to obtain better foaming and vulcanization effects, thereby obtaining silicone rubber with specific properties coated on the conductor.
[0099] The drying tunnel may be configured to include more than two heating sections. In some embodiments, the drying tunnel includes a first heating section and a second heating section, and the conductor coated with the rubber compound passes through the first heating section and the second heating section in sequence, wherein the temperature of the second heating section is higher than the temperature of the first heating section.
[0100] In some embodiments, the drying tunnel includes a first heating section, a second heating section, and a third heating section, and the conductor coated with the rubber compound passes through the first heating section, the second heating section, and the third heating section in sequence, wherein the temperature of the first heating section is 10 to 30°C lower than that of the second heating section, and the temperature of the third heating section is 10 to 20°C higher than that of the second heating section. In some embodiments, the temperature of the first heating section is 120 to 150°C, the temperature of the second heating section is 130 to 160°C, and the temperature of the third heating section is 140 to 170°C.
[0101] refer to Figure 4 , Figure 4 A schematic diagram of a process for preparing a silicone rubber wire according to another embodiment of the present disclosure is shown. Figure 3 The embodiment shown is different in that, in this embodiment, before the rubber mix is applied to the conductor, a shielding layer is formed on the conductor. S21 and S23 correspond to S11 and S13 described in the above embodiment, respectively, and will not be described in detail here.
[0102] In S22, a shielding layer is formed on the conductor, the shielding layer wraps around the outer periphery of the conductor, and then the mixed rubber is coated on the shielding layer. The coating method is similar to that in S12 and is not repeated here. The shielding layer can shield the external electromagnetic interference to the conductor during the use of the silicone rubber wire. In some embodiments, the shielding layer is composed of one or more metals. In some embodiments, the thickness of the shielding layer is 50 to 100 μm.
[0103] refer to Figure 5 , Figure 5 A schematic flow chart of a method for preparing a silicone rubber wire according to another embodiment of the present disclosure is shown. In this embodiment, the mixing includes a first mixing and a second mixing.
[0104] In S31, the initial silicone rubber, flame retardant and cross-linking agent are added to an internal mixer for first mixing, the first mixing temperature is not higher than 50° C., and the mixing is performed for 1 to 3 minutes, and then the pore-forming agent is added to the internal mixer for mixing for 3 to 5 minutes to obtain a first mixing product. In the first mixing product, the initial silicone rubber, flame retardant, cross-linking agent and foaming agent are uniformly mixed, that is, the flame retardant, cross-linking agent and foaming agent are uniformly dispersed in the initial silicone rubber.
[0105] In some embodiments, the pore-forming agent includes a foaming agent, and the first mixing includes: adding the initial silicone rubber, the flame retardant and the cross-linking agent to an internal mixer in sequence, closing the internal mixer, and operating the internal mixer at room temperature to stir the initial silicone rubber, the flame retardant and the cross-linking agent for 1 to 3 minutes; then adding the foaming agent to the internal mixer and continuing to stir for 3 to 5 minutes to obtain a uniformly mixed first mixing product.
[0106] In some embodiments, the pore-forming agent includes a foaming agent and glass microspheres. During the first mixing, the glass microspheres are added together with the foaming agent to enhance the strength of the prepared silicone rubber and reduce its weight.
[0107] The types and amounts of the initial silicone rubber, flame retardant, cross-linking agent, foaming agent and glass beads are the same as those in S11 in the aforementioned embodiment and will not be described in detail here.
[0108] In S32, the first mixed product is added to an open mill for second mixing, the second mixing temperature is not higher than 50°C, and the mixing is performed for 3 to 5 minutes to obtain a rubber compound. Compared with the first mixed product, the components in the raw materials are more evenly mixed in the rubber compound.
[0109] In some embodiments, the roller spacing of the mixing mill is 5 to 15 mm.
[0110] In some embodiments, the obtained rubber mix is cut into suitable rubber strips to be coated on and wrap the conductor.
[0111] In some embodiments, in order to meet the color requirements for the silicone rubber wire, a pigment of a specific color is added to the first mixed product for a second mixing, so that the obtained mixed rubber has a specific color.
[0112] In S33, the rubber mix is applied to the conductor. In some embodiments, the rubber mix is directly applied to the conductor to wrap the conductor. In some embodiments, a shielding layer is first formed on the conductor, the shielding layer has a shielding effect on electromagnetic interference, and then the rubber mix is applied to the shielding layer.
[0113] The coating process of the rubber mix is the same as in S12.
[0114] In S34, the conductor coated with the rubber mix is heated in a drying oven with a length of 20 to 40 m and a temperature of 120° C. to 170° C. to foam and vulcanize the rubber mix coated on the conductor, thereby forming a silicone rubber layer. The foaming and vulcanization methods are the same as those in S13 above, and are not described in detail here.
[0115] In the method for preparing the silicone rubber wire of the embodiment of the present disclosure, the thickness of the silicone rubber before and after foaming is inconsistent. In some embodiments, the thickness of the silicone rubber layer on the conductor after foaming increases by 20% to 200% compared to before foaming. For silicone rubber wire products with a specific silicone rubber layer thickness, according to the method for preparing the silicone rubber wire of the embodiment of the present disclosure, less initial silicone rubber is used in the preparation raw materials, and the thickness of the silicone rubber layer reaches a specific thickness through foaming. The silicone rubber of the embodiment of the present disclosure has a lighter weight, which is 10% to 50% lighter than the unfoamed silicone rubber of the same thickness.
[0116] The method for preparing the silicone rubber wire of the embodiment of the present disclosure adjusts the ratio of each component in the raw materials and each link of the production process to achieve good foaming and vulcanization effects, and finally obtains a silicone rubber wire with a specific thickness of silicone rubber.
[0117] According to the test of "GB / T1040 Determination of Tensile Properties of Plastics", the tensile strength of the outermost silicone rubber layer of the conductor is 0.5~5MPa.
[0118] According to the test of "GB / T1040 Determination of Tensile Properties of Plastics", the elongation at break of the outermost silicone rubber layer of the conductor is 200% to 800%.
[0119] According to the UL94 standard test, the flame retardancy grade of the outermost silicone rubber layer of the conductor is V2 to V0; further, the flame retardancy grade of the silicone rubber layer is above V1; further, the flame retardancy grade of the silicone rubber layer is V0.
[0120] The present disclosure is further described below through specific embodiments.
[0121] Example
[0122] Example 1
[0123] Preparation of silicone rubber wire
[0124] The initial silicone rubber, flame retardant and cross-linking agent are added to an internal mixer for first mixing, the first mixing temperature is not higher than 50° C., and the mixing is performed for 1 minute. Then, a foaming agent with a mass fraction of 0.2% of the total mass of the raw materials is added to the internal mixer and mixed for 5 minutes to obtain a first mixing product; the first mixing product is added to an open mixer for second mixing, the second mixing temperature is not higher than 50° C., and the mixing is performed for 5 minutes to obtain a uniformly mixed rubber;
[0125] The rubber compound is passed through a silicone rubber cable extruder, extruded together with the conductor, so that the rubber compound is coated on the conductor, and the extrusion speed is 1 to 3 m / min;
[0126] The conductor coated with the rubber compound is sent into a drying oven at a temperature of 130° C. at a speed of 1 to 3 m / min for heating, so that the rubber compound coated on the conductor is foamed and vulcanized, thereby forming a silicone rubber layer on the conductor to prepare a silicone rubber wire 1#.
[0127] Performance Characterization of Silicone Rubber Wire
[0128] The SEM image of the cross section of the silicone rubber layer of the silicone rubber wire No. 1. The test results are shown in Figure 6-Figure 8 . Figure 6-Figure 8 The scanning electron microscope images of the cross section of the silicone rubber layer of silicone rubber wire 1# at magnifications of 50 times, 200 times, and 800 times are shown respectively. Figure 6-Figure 8,A number of micropores are formed in the silicone rubber layer of silicone rubber wire 1#. ,Through electron microscope measurement, it can be seen that the pore size of the micropores is 100-150μm.
[0129] The density, tensile strength and elongation at break of silicone rubber wire 1# were tested. The test results are shown in Table 1.
[0130] Example 2
[0131] Preparation of silicone rubber wire
[0132] The initial silicone rubber, flame retardant and cross-linking agent are added to an internal mixer for first mixing, the first mixing temperature is not higher than 50° C., and the mixing is performed for 1 minute. Then, 0.5% of the mass fraction of the foaming agent and 1% of the mass fraction of the glass microbeads are added to the internal mixer for mixing for 5 minutes to obtain a first mixing product; the first mixing product is added to an open mixer for second mixing, the second mixing temperature is not higher than 50° C., and the mixing is performed for 5 minutes to obtain a uniformly mixed rubber;
[0133] The rubber compound is passed through a silicone rubber cable extruder, extruded together with the conductor, so that the rubber compound is coated on the conductor, and the extrusion speed is 1 to 3 m / min;
[0134] The conductor coated with the rubber compound is sent into a drying oven at a temperature of 130° C. at a speed of 1 to 3 m / min for heating, so that the rubber compound coated on the conductor is foamed and vulcanized, thereby forming a silicone rubber layer on the conductor to prepare a silicone rubber wire 2#.
[0135] Performance Characterization of Silicone Rubber Wire
[0136] The SEM image of the cross section of the silicone rubber layer of the silicone rubber wire No. 2. The test results are shown in Figure 9-12 . Figure 9-12 The scanning electron microscope images of the cross section of the silicone rubber layer of silicone rubber wire 2# at magnifications of 50 times, 200 times, 800 times, and 500 times are shown respectively. Figure 9-12 In the silicone rubber layer of silicone rubber wire 2#, a number of micropores are formed, including first micropores formed by a foaming agent and second micropores formed by glass beads. Through electron microscope measurements, it can be seen that the pore size of the first micropore is 70-150μm, and the pore size of the second micropore is 30-100μm.
[0137] The density, tensile strength and elongation at break of silicone rubber wire 2# were tested. The test results are shown in Table 1.
[0138] Comparative Example 1
[0139] Preparation of silicone rubber wire
[0140] The initial silicone rubber, flame retardant and cross-linking agent are added to an internal mixer for first mixing, the first mixing temperature is not higher than 50° C., and the mixing is performed for 1 minute. Then, a foaming agent with a mass fraction of 1.5% of the total mass of the raw materials is added to the internal mixer and mixed for 5 minutes to obtain a first mixing product; the first mixing product is added to an open mixer for second mixing, the second mixing temperature is not higher than 50° C., and the mixing is performed for 5 minutes to obtain a uniformly mixed rubber;
[0141] The rubber compound is passed through a silicone rubber cable extruder, extruded together with the conductor, so that the rubber compound is coated on the conductor, and the extrusion speed is 1 to 3 m / min;
[0142] The conductor coated with the rubber compound is sent into a drying oven at a temperature of 130° C. at a speed of 1 to 3 m / min for heating, so that the rubber compound coated on the conductor is foamed and vulcanized, thereby forming a silicone rubber layer on the conductor to prepare a silicone rubber wire 3#.
[0143] Performance Characterization of Silicone Rubber Wire
[0144] Fig.13 The following are photos of the silicone rubber wire 2# of Example 2 according to a specific embodiment of the present disclosure and the silicone rubber wire 3# of Comparative Example 1, wherein the 2# wire is a photo of the silicone rubber wire 2#, and the 3# wire is a photo of the silicone rubber wire 3#. Fig.13 The surface of silicone rubber wire 3# is uneven, indicating that micropores are formed on the surface of silicone rubber wire 3#, which affects the glossiness and flatness. If there are micropores on the surface, gas can easily enter the micropores, which may affect the performance of silicone rubber wire 3# over time; the surface glossiness of silicone rubber wire 2# is good, the surface is smooth, and its performance has better stability.
[0145] The density, tensile strength and elongation at break of silicone rubber wire 3# were tested. The test results are shown in Table 1.
[0146] Table 1 Density, tensile strength and elongation at break test of silicone rubber wire
[0147] Test samples <![CDATA[Density (g / cm 3 )]]> Tensile strength(MPa) Elongation at break (%) Silicone rubber wire 1# 0.92 1.4 476 Silicone rubber wire 2# 0.81 1.6 362 Silicone rubber wire 3# 0.79 0.83 162
[0148] As can be seen from Table 1, both silicone rubber wire 1# and silicone rubber wire 2# have good tensile strength and elongation at break, and silicone rubber wire 2# has a smaller density and greater tensile strength. The tensile strength and elongation at break of silicone rubber wire 3# are lower than those of silicone rubber wire 1# and silicone rubber wire 2#. The raw materials of silicone rubber wire 2# include 0.5% by mass of foaming agent and 1% by mass of glass microbeads, while the raw materials of silicone rubber wire 3# include 1.5% by mass of foaming agent. Both silicone rubber wire 2# and silicone rubber wire 3# have a lighter weight than conventional silicone rubber wires. The density of silicone rubber wire 2# and silicone rubber wire 3# are similar, but silicone rubber wire 2# has better tensile strength and elongation at break than silicone rubber wire 3#. Therefore, too much foaming agent will affect the performance of the silicone rubber layer, while the addition of glass microbeads can further reduce the weight of the silicone rubber layer on the basis of adding a certain amount of foaming agent, while achieving the purpose of weight reduction without affecting the performance of the silicone rubber layer.
[0149] Silicone rubber wire 1# and silicone rubber wire 2# can both meet the use requirements of silicone rubber wires and are lighter in weight than conventional silicone rubber wires.
[0150] Therefore, the silicone rubber wire prepared by the preparation method of the embodiment of the present invention has good tensile strength, toughness and flame retardant grade, can meet the use requirements of silicone rubber wire, and at the same time has a lighter weight and less initial silicone rubber usage, thereby reducing the use of initial silicone rubber raw materials and saving costs.
[0151] The above is only an exemplary embodiment used to illustrate the principle of the present disclosure, and is not intended to limit the scope of protection of the present disclosure. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also within the scope of protection of the present disclosure.
Claims
1. A silicone rubber wire, comprising: The conductor is characterized in that it also includes: The silicone rubber layer is wrapped around the outer periphery of the conductor, and the silicone rubber layer includes a plurality of micropores, and the pore diameter of the micropores is 10 to 250 μm.
2. The silicone rubber wire according to claim 1, characterized in that: The micropores include first micropores, the first micropores are formed by foaming a foaming agent, and the pore diameter of the first micropores is 10 to 250 μm.
3. The silicone rubber wire according to claim 2, characterized in that: The pore size of the first micropores is 15-150 μm.
4. The silicone rubber wire according to claim 2, characterized in that: The foaming agent is an expanded microsphere foaming agent.
5. The silicone rubber wire according to claim 2, characterized in that: The micropores further include second micropores, the second micropores are formed by glass microbeads, and the pore diameter of the second micropores is 10-100 μm.
6. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: The tensile strength of the silicone rubber layer is 0.5-5 MPa.
7. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: The breaking elongation of the silicone rubber layer is 200% to 800%.
8. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: The flame retardant grade of the silicone rubber layer is V2-V0.
9. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: The thickness of the silicone rubber layer is 0.3-2 mm.
10. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: The density of the silicone rubber layer is 0.5-1.0 g / cm 3 .
11. The silicone rubber wire according to any one of claims 1 to 5, characterized in that: Also includes: The shielding layer is located between the silicone rubber layer and the conductor and is wrapped around the outer periphery of the conductor.
12. The silicone rubber wire according to claim 11, characterized in that: The material of the shielding layer includes aluminum foil.
13. A method for preparing a silicone rubber wire, characterized in that: include: Mixing raw materials including initial silicone rubber, flame retardant, pore former and cross-linking agent to obtain a rubber mixture; Applying the rubber mixture on a conductor; The conductor coated with the rubber mix is heated to make the rubber mix foam and vulcanize to form a silicone rubber layer. The pore former is used to form a plurality of micropores distributed in the silicone rubber layer. The pore diameter of the micropores is 10 to 250 μm.
14. The preparation method according to claim 13, characterized in that: The pore-forming agent includes a foaming agent, and the mass fraction of the foaming agent in the raw material is 0.1% to 0.5%.
15. The preparation method according to claim 13, characterized in that: The foaming agent is used to form first micropores, and the pore diameter of the first micropores is 10 to 250 μm.
16. The preparation method according to claim 14, characterized in that: The foaming agent is an expandable microsphere foaming agent, the particle size of the foaming agent is 5 to 50 μm, and the expansion ratio of the foaming agent is 2 to 5 times.
17. The preparation method according to claim 16, characterized in that: After foaming, the thickness of the silicone rubber layer on the conductor increases by 20% to 200% compared with that before foaming.
18. The preparation method according to claim 13, characterized in that: The initial silicone rubber includes: one or more of dimethyl silicone rubber, methyl vinyl silicone rubber, methyl vinyl phenyl silicone rubber and methyl vinyl trifluoropropyl silicone rubber; The mass fraction of the initial silicone rubber in the raw material is 57.5% to 93.4%.
19. The preparation method according to claim 13, characterized in that: The mass fraction of the flame retardant in the raw material is 5% to 35%; the flame retardant includes: one or more of aluminum hydroxide, magnesium hydroxide and zinc borate.
20. The preparation method according to claim 13, characterized in that: The mass fraction of the crosslinking agent in the raw material is 0.5% to 2%; the crosslinking agent includes one or more of 2,4-dichlorobenzoyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, diisopropylbenzene peroxide and platinum vulcanizing agent.
21. The preparation method according to claim 13, characterized in that: The mixing comprises: The first mixing includes: adding the initial silicone rubber, flame retardant and cross-linking agent into an internal mixer and mixing for 1 to 3 minutes, and then adding the pore-forming agent into the internal mixer and mixing for 3 to 5 minutes to obtain a first mixing product; the mixing temperature of the first mixing is not higher than 50°C.
22. The preparation method according to claim 14, characterized in that: The pore-forming agent further comprises glass microspheres, and the mass fraction of the glass microspheres in the raw material is 1% to 5%.
23. The preparation method according to claim 22, characterized in that: The particle size of the glass microbeads is 10-100 μm. The glass microbeads are used to form second micropores distributed in the silicone rubber layer.
24. The preparation method according to claim 21, characterized in that: The mixing also includes: The second mixing includes: adding the first mixing product into an open mill and mixing for 3 to 5 minutes to obtain a mixed rubber; the mixing temperature used in the second mixing is not higher than 50° C., and the roller distance of the open mill is 5 to 15 mm.
25. The preparation method according to claim 13, characterized in that: The heating temperature is 120° C. to 170° C., the length of the heating drying tunnel is 20 to 40 m, and the moving speed of the conductor coated with the rubber compound in the drying tunnel is 1 to 10 m / min.
26. The preparation method according to claim 13, characterized in that: Before the rubber mix is coated on the conductor, a shielding layer is first formed on the conductor, and the shielding layer wraps the conductor.