Silicone rubber composite material and preparation method and application thereof
阅读说明：本技术 一种硅橡胶复合材料及其制备方法和应用 (Silicone rubber composite material and preparation method and application thereof ) 是由 贺志文 赵志 李颖 郝玉义 吴瑞清 于 2021-08-11 设计创作，主要内容包括：本发明提供了一种硅橡胶复合材料及其制备方法和应用。本发明的硅橡胶复合材料,第一硅橡胶胶泥层和第二硅橡胶胶泥层提供了优异的可塑型性和湿气自固化能力。固化后具备较高的拉伸强度和优异的电气绝缘性能、防水性和耐候性。在保质期内且随着放置时间延长,强度和体积电阻率不会大幅下降。增强层绝缘性优异。第一硅橡胶胶泥层、增强层和第二硅橡胶胶泥层依次叠加的结构设计,使得复合材料在接触水气固化前具备可塑形性和一定的耐刺穿性,固化后的机械强度提高,适用于包覆带有尖角、尖刺等不规则结构的基体。(The invention provides a silicone rubber composite material and a preparation method and application thereof. The silicone rubber composite material, the first silicone rubber cement layer and the second silicone rubber cement layer of the present invention provide excellent moldability and moisture self-curing ability. After curing, the composite material has higher tensile strength and excellent electrical insulation performance, waterproofness and weather resistance. Strength and volume resistivity do not drop significantly over shelf life and with extended shelf life. The reinforcing layer is excellent in insulation. The structural design that first silicon rubber cement layer, enhancement layer and second silicon rubber cement layer superpose in proper order for combined material possesses shapeability and certain puncture resistance before the solidification of contact aqueous vapor, and the mechanical strength after the solidification improves, is applicable to the cladding and has the base member of irregular structure such as closed angle, spine.)
1. The utility model provides a silicon rubber composite which characterized in that, is including the first silicon rubber cement layer, enhancement layer and the second silicon rubber cement layer that set gradually, the preparation raw materials of first silicon rubber cement layer and second silicon rubber cement layer include alkoxy end-capped polydimethylsiloxane, reinforcement filler, weight gain filler, fire retardant, plasticizer, vulcanizer, coupling agent and catalyst, alkoxy end-capped polydimethylsiloxane is viscosity 150000mPa · s ~ 300000mPa · s's trialkoxy end-capped polydimethylsiloxane.
2. The silicone rubber composite according to claim 1, wherein the trialkoxy terminated polydimethylsiloxane has a structure as shown below:
3. the silicone rubber composite material according to claim 1, wherein the material of the reinforcement layer comprises at least one of aramid paper and glass fiber cloth.
4. The silicone rubber composite material according to any one of claims 1 to 3, wherein the raw materials for preparing the first and second silicone rubber cement layers comprise, in parts by weight:
alkoxy-terminated polydimethylsiloxane: 100 parts of (a) a water-soluble polymer,
reinforcing filler: 15 to 35 portions of the mixture of the components,
weight-increasing filler: 25 to 60 portions of the mixture of the components,
flame retardant: 20 to 50 portions of the raw materials, and the like,
plasticizer: 0.5 to 3 portions of the raw materials,
vulcanizing agent: 1 to 4 portions of the raw materials are mixed,
coupling agent: 1 to 3 parts of (A) to (B),
catalyst: 0.5 to 3 portions.
5. The silicone rubber composite according to any one of claims 1 to 4, characterized in that the thickness of the silicone rubber composite is 1.5mm to 3.0 mm.
6. The silicone rubber composite according to any one of claims 1 to 4, characterized in that the thickness of the first silicone rubber cement layer is 0.6mm to 1.0 mm.
7. The silicone rubber composite according to any one of claims 1 to 4, characterized in that the thickness of the second silicone rubber cement layer is 0.6mm to 1.0 mm.
8. A method of preparing the silicone rubber composite material as claimed in any of claims 1 to 7, characterized in that the first silicone rubber cement layer, the reinforcing layer and the second silicone rubber cement layer are co-extruded after being pressed together.
9. Use of a silicone rubber composite material as claimed in any of claims 1 to 8 in high voltage power supply.
10. The use according to claim 9, characterized in that the use comprises a method for sheathing insulated wire clamps and insulated switches.
Technical Field
The invention belongs to the technical field of insulating materials, and particularly relates to a silicone rubber composite material and a preparation method and application thereof.
Background
Urban power supply lines of 10kV or below are usually inserted into urban living areas, and wire clamps, electrical connection points and partial overhead bare wires of the urban power supply lines need to keep a certain electrical safety distance from the surrounding environment so as to ensure personal safety around the lines and stable operation of the lines. In a scenario where a part of the electrical safety distance is insufficient, it is necessary to perform a local insulation process on the power transmission line.
Tape wrapping is a common method for localized insulation treatment, but 10kV power supply lines are usually exposed to outdoor conditions, and most of the tapes, such as polyurethane, polyvinyl chloride, ethylene propylene rubber, have poor weather resistance. The silica gel self-adhesive tape has good weather resistance and insulation, but the base material is a cured silicone rubber material, so the silica gel self-adhesive tape is generally adhered and jointed with the base material needing insulation treatment, and the waterproof and dustproof properties cannot be ensured. Although materials such as paint and glue have excellent bonding property and adhesion property with a base material, the materials are easy to flow, and a thick coating cannot be formed to ensure insulation property and convenience in construction.
CN107033599B discloses a flame-retardant single-component moisture-curing silicone rubber, which takes alkoxy silane as a cross-linking agent, is a strip material with high plasticity before contacting moisture in the air, can be tightly wrapped on an electrical exposed part with an irregular structure within a period of time just contacting the air, has certain mechanical strength, good electrical performance and good bonding effect with a wrapped substrate after being cured and shaped for a certain period of time, and finally realizes the insulation and waterproof effect which cannot be achieved by a common insulation tape or paint. However, in practical applications, the substrate to be coated is usually irregular structures with sharp corners and spikes, and the strength of the tape-like mortar when uncured is insufficient to resist the penetration of these irregular structures, thereby easily causing breakage or exposing the metal and losing the function of the insulating coating. The method of using fiber fabrics such as glass fiber cloth and non-woven fabrics to compound with polymer materials to improve the puncture resistance of the materials is a common method, and CN201400652 discloses a glass fiber reinforced organic silicon rubber self-adhesive tape, wherein a plain alkali-free glass fiber tape is used as a framework, organic silicon rubber with self-adhesion is extruded and pasted on the surface, and the compounded material is not easy to damage after being stressed and impacted. However, moisture-curable silicone rubber materials have low strength before curing and must be prevented from contacting air and moisture, so that a general method of laminating a polymer and a fiber fabric is not suitable. In addition, the fiber fabric for reinforcement must have a certain binding force with the daub before and after curing, and particularly, the silica gel layer and the fiber fabric cannot be layered after curing. The insulation and flame retardancy of the fiber fabric itself may also have an impact on the corresponding properties of the composite.
Disclosure of Invention
The present invention is directed to solving at least one of the above problems in the prior art. Therefore, the invention provides a silicon rubber composite material which has plasticity and certain puncture resistance before being cured by contacting with water vapor, has improved mechanical strength after being cured, and is suitable for coating a substrate with irregular structures such as sharp corners, sharp spines and the like.
The invention also provides a preparation method of the silicon rubber composite material.
The invention also provides application of the silicon rubber composite material.
The invention provides a silicone rubber composite material, which comprises a first silicone rubber cement layer, a reinforcing layer and a second silicone rubber cement layer which are sequentially arranged, wherein the preparation raw materials of the first silicone rubber cement layer and the second silicone rubber cement layer comprise alkoxy end-capped polydimethylsiloxane, reinforcing filler, weight-increasing filler, a flame retardant, a plasticizer, a vulcanizing agent, a coupling agent and a catalyst, and the alkoxy end-capped polydimethylsiloxane is trialkoxy end-capped polydimethylsiloxane with the viscosity of 150000mPa & s-300000 mPa & s.
The invention relates to a technical scheme of a silicon rubber composite material, which at least has the following beneficial effects:
the silicone rubber composite material, the first silicone rubber cement layer and the second silicone rubber cement layer of the present invention provide excellent moldability and moisture self-curing ability. After curing, the composite material has higher tensile strength and excellent electrical insulation performance, waterproofness and weather resistance. Strength and volume resistivity do not drop significantly over shelf life and with extended shelf life. The reinforcing layer is excellent in insulation. The structural design that first silicon rubber cement layer, enhancement layer and second silicon rubber cement layer superpose in proper order for combined material possesses shapeability and certain puncture resistance before the solidification of contact aqueous vapor, and the mechanical strength after the solidification improves, is applicable to the cladding and has the base member of irregular structure such as closed angle, spine.
According to the silicone rubber composite material, the preparation raw materials of the first silicone rubber cement layer and the second silicone rubber cement layer comprise alkoxy-terminated polydimethylsiloxane, compared with hydroxyl-terminated polydimethylsiloxane, the hydroxyl at the tail end of the polydimethylsiloxane is an active crosslinking point, and each molecular chain only has 2 crosslinking points. In the silicon rubber composite material, alkoxy-terminated polydimethylsiloxane is trialkoxy-terminated polydimethylsiloxane with the viscosity of 150000-300000 mPa & s, and alkoxy at the tail end is an active crosslinking point, namely 6 crosslinking points exist in each molecular chain, so that the crosslinking density is greatly improved, and the tensile strength is improved.
According to some embodiments of the invention, the reinforcing filler has a specific surface area of 100m2/g～400m2The hydrophobic fumed silica is/g.
The reinforcing filler is hydrophobic fumed silica, and has the advantages that the hydroxyl content of the hydrophobic fumed silica is extremely low, the mixing uniformity can be improved, and the storability of the silicone rubber can be improved.
The specific surface area of the reinforcing filler is 100m2/g～400m2The white carbon black has the advantages that the white carbon black with the specific surface area within the range has a good thickening effect to ensure the Mooney viscosity, and is relatively easy to disperse to ensure the mixing uniformity.
According to some embodiments of the invention, the weighting filler comprises activated light calcium carbonate.
According to some embodiments of the invention, the flame retardant comprises at least one of decabromodiphenyl ether, decabromodiphenyl ethane, decabromodiphenyl.
According to some embodiments of the invention, the plasticizer comprises a dimethicone having a viscosity of from 1000 to 30000 mPa-s.
According to some embodiments of the invention, the vulcanizing agent comprises at least one of methyltrimethoxysilane, methyltriethoxysilane, vinyltrimethoxysilane, aminopropyltriethoxysilane, and dimethyldiethoxysilane.
According to some embodiments of the invention, the coupling agent comprises 3- (2, 3-glycidoxy) propyltrimethoxysilane having a CAS number of 2530-83-8.
According to some embodiments of the invention, the catalyst comprises at least one of dibutyltin dilaurate, chelated tin, tetra-n-butyl titanate, and chelated titanium.
According to some embodiments of the invention, the material of the reinforcement layer comprises at least one of aramid paper and glass fiber cloth.
According to some embodiments of the invention, the thickness of the reinforcement layer is between 0.1mm and 0.8 mm.
According to some embodiments of the invention, the aramid paper is an uncalendered meta-aramid paper having a size of 0.2mm to 0.6mm in its position.
The advantage of the uncalendered meta-aramid paper at least comprises the characteristics that the meta-aramid paper has low thickness and is puncture-resistant, the insulativity and the flame retardance of the composite material are not influenced, the uncalendered paper surface is rougher, and the uncalendered meta-aramid paper has a better combination effect with the silica gel layer.
Calendering of paper refers to the use of a calender to improve the smoothness, gloss, and thickness uniformity of the paper.
According to some embodiments of the invention, the glass fiber cloth comprises an alkali-free glass fiber cloth.
According to some embodiments of the invention, the alkali-free glass fiber cloth has a thickness of 0.10mm to 0.4mm, an alkali metal content of less than 0.5%, and a gram weight of 100g/m2～220g/m2The glass fiber cloth of (1).
The advantages of fiberglass cloth having the above characteristics include at least low thickness, puncture resistance, no impact on the insulation and flame retardancy of the composite.
According to some embodiments of the invention, the trialkoxy terminated polydimethylsiloxane has a structure as shown below:
according to some embodiments of the present invention, the raw materials for preparing the first and second silicone rubber cement layers comprise, in parts by weight:
alkoxy-terminated polydimethylsiloxane: 100 parts of (a) a water-soluble polymer,
reinforcing filler: 15 to 35 portions of the mixture of the components,
weight-increasing filler: 25 to 60 portions of the mixture of the components,
flame retardant: 20 to 50 portions of the raw materials, and the like,
plasticizer: 0.5 to 3 portions of the raw materials,
vulcanizing agent: 1 to 4 portions of the raw materials are mixed,
coupling agent: 1 to 3 parts of (A) to (B),
catalyst: 0.5 to 3 portions.
According to some embodiments of the invention, the silicone rubber composite has a thickness of 1.5mm to 3.0 mm.
According to some embodiments of the invention, the first layer of silicone mastic has a thickness of 0.6mm to 1.0 mm.
According to some embodiments of the invention, the second layer of silicone mastic has a thickness of 0.6mm to 1.0 mm.
The second aspect of the present invention provides a method for preparing the above silicone rubber composite material, which comprises laminating the first silicone rubber cement layer, the reinforcing layer and the second silicone rubber cement layer, and then co-extruding them.
The invention relates to a technical scheme of a preparation method of a silicon rubber composite material, which at least has the following beneficial effects:
the preparation method has simple steps and mild process conditions, and can realize large-scale production without complex equipment.
According to some embodiments of the present invention, a method of preparing a silicone rubber composite comprises the steps of:
adding trialkoxy terminated polydimethylsiloxane into a vacuum kneader, then adding reinforcing filler, weight-increasing filler, flame retardant and plasticizer, and mixing for 0.5-2 h at 70-100 ℃.
Starting vacuum to a kneader, keeping the pressure in the kneader between-0.09 MPa and-0.10 MPa, continuing to knead for 0.5h to 2h, heating to 110 ℃ to 140 ℃, and continuing to knead until the Mooney viscosity of the rubber compound in the kneader reaches 12 to 18(55 ℃, 1+4 min).
And cooling the rubber compound to below 60 ℃, adding a vulcanizing agent, a coupling agent and a catalyst under the condition of air and water gas isolation, keeping the temperature of 50-60 ℃ for continuously kneading for 0.5-2 h, then conveying the rubber compound into an extruder under the protection of nitrogen, wherein the Mooney viscosity of the material is 6-9 (55 ℃/1+4 min).
After being unreeled, the fiber fabric at the die head is drawn by a positioning wheel to pass through a die cavity which is narrowed and widened, the sizing material is divided into two strands which are respectively extruded on the fiber fabric from the upper side and the lower side and are extruded together with the fiber fabric, and after being covered by a release film, the sizing material is drawn by a lower conveying belt and an upper driving press roll and is conveyed forwards. The linear speeds of the positioning wheel, the driving press roll and the conveyor belt are kept consistent, and meanwhile, a certain tension is formed to tighten the sheet material, so that the fiber fabric is kept to be conveyed horizontally.
And cutting the continuous sheet, and then carrying out vacuum sealing, packaging and storing.
A third aspect of the invention provides the use of the above silicone rubber composite in high voltage power supply.
According to some embodiments of the invention, the application comprises for sheathing insulated wire clamps and insulated switches.
According to some embodiments of the invention, the application scenarios are such as damaged cable rubber-plastic sheath with sharp spikes, overhead wire clamps, insulated switch connection points that are not easily polished or shaved.
One of the technical schemes of the gel material of the invention at least has the following beneficial effects:
according to the silicone rubber composite material disclosed by the embodiment of the invention, due to the compounding of the aramid paper or the glass fiber cloth, the material has better puncture resistance when being coated and used (before being vulcanized), and is convenient for coating a structure with sharp puncture edges. Because the meta-aramid fiber and the alkali-free glass fiber cloth with excellent insulativity are selected as the composite layer, the electrical insulativity of the cured composite material is not obviously reduced, and the use requirement is met. Due to the adoption of the coextrusion method, the contact between the silica gel layer and the water vapor in the air is reduced, the compactness between the composite layer and the silica gel layer is increased, the advanced solidification of the material is avoided, and the reduction of the binding force between the composite layer and the silica gel layer caused by air wrapping is avoided.
Drawings
Fig. 1 is a schematic structural view of a silicone rubber composite.
Fig. 2 is a schematic view of a process for preparing the silicone rubber composite.
Reference numerals:
1: a first silicone rubber cement layer;
2: a second silicone rubber cement layer;
3: an enhancement layer;
4: a fiber fabric;
5: positioning wheels;
6: sizing material;
7: a release film;
8: a driving compression roller;
9: and (4) a conveyor belt.
Detailed Description
The following are specific examples of the present invention, and the technical solutions of the present invention will be further described with reference to the examples, but the present invention is not limited to the examples.
Example 1
The structure of the silicone rubber composite material prepared in this embodiment is shown in fig. 1, where in fig. 1, 1 is a first silicone rubber cement layer, 2 is a second silicone rubber cement layer, and 3 is an enhancement layer. The preparation method comprises the following specific steps:
100kg of a trialkoxy-terminated polydimethylsiloxane having a viscosity of 150000 mP.s were charged in a vacuum kneader, 25kg of which was then charged with a specific surface area of 120m2Each g of the hydrophobic fumed silica, 42kg of activated light calcium carbonate, 35kg of decabromobiphenyl and 2kg of dimethicone having a viscosity of 5000 mPas were kneaded at 70 ℃ for 1 hour.
The vacuum is started until the pressure in the kneader is-0.098 MPa, the temperature is raised to 125 ℃ after the kneading is continued for 1.5 hours, and the kneading is continued until the Mooney viscosity of the rubber compound in the kneader reaches 15(55 ℃, 1+4 min).
Cooling the rubber compound to below 60 ℃, adding 2.5kg of methyltrimethoxysilane, 2kg of 3- (2, 3-epoxypropoxy) propyltrimethoxysilane and 1.5kg of tetra-n-butyl titanate under the condition of isolating air and moisture, keeping the temperature at 55 ℃ and kneading for 1 hour, then keeping the Mooney viscosity of the material at 7.5-8.0(55 ℃/1+4min), and conveying the rubber compound into an extruder under the protection of nitrogen.
The thickness of the back surface of the die head is 0.2mm, and the gram weight is 170g/m2The alkali-free glass fiber cloth is unreeled, then is drawn by a positioning wheel to pass through a narrow and widened die cavity, the glue material is divided into two strands which are respectively extruded on the alkali-free glass fiber cloth from the upper side and the lower side and are extruded together with the alkali-free glass fiber cloth, and after being covered by a release film, the glue material is drawn by a lower conveying belt and an upper driving press roll and is conveyed forwards. Positioning wheel, driving press roller and driving transmission rollerThe linear speed of the belt is kept consistent, and simultaneously, a certain tension is formed to tighten the sheet material, so that the fiber fabric is kept to be horizontally conveyed. And cutting the continuous sheet, and then carrying out vacuum sealing, packaging and storing.
Further, the overall preparation process of the silicone rubber composite material is shown in fig. 2, wherein 4 is a fiber fabric, i.e., alkali-free glass fiber cloth, 5 is a positioning wheel, 6 is a sizing material, 7 is a release film, 8 is a driving press roll, and 9 is a conveyor belt. During preparation, the prepared sizing material is conveyed into an extruder under the protection of nitrogen, after the alkali-free glass fiber cloth on the back surface of a die head is unreeled, the sizing material is drawn by a positioning wheel 5 to pass through a die cavity which is widened from narrow to wide, the sizing material 6 is divided into two strands, the two strands are respectively extruded on the alkali-free glass fiber cloth from the upper side and the lower side and are extruded together with the alkali-free glass fiber cloth, and after the two strands are covered by a release film 7, the two strands are drawn by a lower conveying belt 9 and an upper driving press roll 8 and are conveyed forwards. The linear speeds of the positioning wheel 5, the driving press roller 8 and the conveyor belt 9 are kept consistent, so that a stretched sheet with certain tension is formed, and the continuous sheet is cut and then is subjected to vacuum sealing packaging and storage.
Example 2
The embodiment prepares the silicone rubber composite material, and the preparation method comprises the following specific steps:
100kg of a trialkoxy-terminated polydimethylsiloxane having a viscosity of 200000 mP.s were charged into a vacuum kneader, and 20kg of a polydimethylsiloxane having a specific surface area of 240m were then added2Each g of the hydrophobic fumed silica, 35kg of activated light calcium carbonate, 35kg of decabromobiphenyl and 2kg of dimethicone having a viscosity of 5000 mPas were kneaded at 80 ℃ for 1.5 hours.
The vacuum is started until the pressure in the kneader is-0.098 MPa, the temperature is raised to 125 ℃ after the kneading is continued for 1.5 hours, and the kneading is continued until the Mooney viscosity of the rubber compound in the kneader reaches 15(55 ℃, 1+4 min).
Cooling the mixed rubber to below 60 ℃, adding 2.0kg of methyltrimethoxysilane, 1.6kg of 3- (2, 3-epoxypropoxy) propyl trimethoxysilane and 1.5kg of tetra-n-butyl titanate under the condition of air and moisture isolation, keeping the temperature at 55 ℃ and kneading for 1 hour, then keeping the Mooney viscosity of the material at 7.5-8.0(55 ℃/1+4min), and conveying the rubber material into an extruder under the protection of nitrogen.
After being unreeled, the unpressed meta-aramid paper with the thickness of 0.4mm on the back of the die head is drawn by a positioning wheel to pass through a die cavity which is widened from narrow to wide, the glue stock is divided into two strands which are respectively extruded on the alkali-free glass fiber cloth from the upper side and the lower side and are extruded together with the alkali-free glass fiber cloth, and after being covered by a release film, the glue stock is drawn by a lower conveying belt and an upper driving compression roller and is conveyed forwards. The linear speeds of the positioning wheel, the driving press roll and the conveyor belt are kept consistent, and meanwhile, a certain tension is formed to tighten the sheet material, so that the fiber fabric is kept to be conveyed horizontally. And cutting the continuous sheet, and then carrying out vacuum sealing, packaging and storing.
COMPARATIVE EXAMPLE 1 (without reinforcing layer)
The comparative example prepares a silicone rubber composite material, and the preparation method comprises the following specific steps:
100kg of trialkoxy-terminated polydimethylsiloxane having a viscosity of 150000 mPas was charged in a vacuum kneader, and then 25kg of hydrophobic fumed silica having a specific surface area of 120m2/g, 42kg of activated light calcium carbonate, 35kg of decabromobiphenyl and 2kg of dimethylsilicone oil having a viscosity of 5000 mPas were added and kneaded at 70 ℃ for 1 hour.
The vacuum is started until the pressure in the kneader is-0.098 MPa, the temperature is raised to 125 ℃ after the kneading is continued for 1.5 hours, and the kneading is continued until the Mooney viscosity of the rubber compound in the kneader reaches 15(55 ℃, 1+4 min). Cooling the rubber compound to below 60 ℃, adding 2.5kg of methyltrimethoxysilane, 2kg of 3- (2, 3-epoxypropoxy) propyltrimethoxysilane and 1.5kg of tetra-n-butyl titanate under the condition of isolating air and moisture, keeping the temperature at 55 ℃ and kneading for 1 hour, then keeping the Mooney viscosity of the material at 7.5-8.0(55 ℃/1+4min), and conveying the rubber compound into an extruder under the protection of nitrogen.
After the upper surface and the lower surface of the sizing material are covered by release films, the sizing material is pulled by a lower conveying belt and conveyed forwards, and the continuous sheet is cut and then is packaged and stored in a vacuum sealing mode.
Comparative example 2 (Using a Polyamide nonwoven as a reinforcing layer)
The comparative example prepares a silicone rubber composite material, and the preparation method comprises the following specific steps:
100kg of a trialkoxy-terminated polydimethylsiloxane having a viscosity of 150000 mP.s were charged in a vacuum kneader, 25kg of which was then charged with a specific surface area of 120m2Per g of hydrophobic fumed silica and 42kg of active light-weightThe mixture was kneaded at 70 ℃ for 1 hour with calcium carbonate, 35kg of decabromobiphenyl and 2kg of dimethylsilicone oil having a viscosity of 5000 mPas.
The vacuum is started until the pressure in the kneader is-0.098 MPa, the temperature is raised to 125 ℃ after the kneading is continued for 1.5 hours, and the kneading is continued until the Mooney viscosity of the rubber compound in the kneader reaches 15(55 ℃, 1+4 min).
Cooling the rubber compound to below 60 ℃, adding 2.5kg of methyltrimethoxysilane, 2kg of 3- (2, 3-epoxypropoxy) propyltrimethoxysilane and 1.5kg of tetra-n-butyl titanate under the condition of isolating air and moisture, keeping the temperature at 55 ℃ and kneading for 1 hour, then keeping the Mooney viscosity of the material at 7.5-8.0(55 ℃/1+4min), and conveying the rubber compound into an extruder under the protection of nitrogen.
On the back of the die head, the thickness is about 0.2mm, and the gram weight is 30g/m2The polyamide non-woven fabric is drawn by a positioning wheel to pass through a narrow and widened die cavity after being unreeled, the glue material is divided into two strands which are respectively extruded on the alkali-free glass fiber fabric from the upper side and the lower side and are extruded together with the alkali-free glass fiber fabric, and after being covered by a release film, the glue material is drawn by a lower conveying belt and an upper driving press roll and is conveyed forwards. The linear speeds of the positioning wheel, the driving press roll and the conveyor belt are kept consistent, and meanwhile, a certain tension is formed to tighten the sheet material, so that the fiber fabric is kept to be conveyed horizontally. And cutting the continuous sheet, and then carrying out vacuum sealing, packaging and storing.
Example of detection
The properties of the silicone rubber composites prepared in examples 1, 2 and comparative examples 1, 2 were tested. The test results and the test standards according to are shown in table 1.
TABLE 1
Wherein, the power frequency withstand voltage (C.1 type electrode, alternating current, kV) combined sample after being coated with metal is subjected to electrical test, and the electrode is selected from C.1 and C.3.
Compared with the comparative example 1 without adding the reinforcing layer, the volume resistivity, the breakdown strength, the dielectric constant and the dielectric loss of the material are not greatly changed when the alkali-free glass fiber cloth and the meta-aramid paper are respectively used as the reinforcing layers in the examples 1 and 2, while the polyamide non-woven fabric is used as the reinforcing layer in the comparative example 2, the volume resistivity and the breakdown voltage of the material are greatly reduced, the dielectric constant and the dielectric loss are improved, and the material is not suitable for being used as a high-voltage insulating coating material.
Although the material of comparative example 1 has the best electrical property test result, but has no puncture-resistant and deformation-resistant properties because of no reinforced layer, when the material is coated with the C.1 type regular round rod electrode, the industrial frequency withstand voltage of comparative example 1, example 1 and example 2 is more than 18kV according to the test of DL/T2135-20206.4.4, but when the material is coated with the C.3 type special-shaped electrode, the industrial frequency withstand voltage test result of comparative example 1 without the reinforced layer is obviously reduced.
After the cold and hot shock, the silica gel layer and the reinforcing layer are not separated.
According to the silicone rubber composite material disclosed by the embodiment of the invention, due to the compounding of the aramid paper or the glass fiber cloth, the material has better puncture resistance when being coated and used (before being vulcanized), and is convenient for coating a structure with sharp puncture edges. Because the meta-aramid fiber and the alkali-free glass fiber cloth with excellent insulativity are selected as the composite layer, the electrical insulativity of the cured composite material is not obviously reduced, and the use requirement is met. Due to the adoption of the coextrusion method, the contact between the silica gel layer and the water vapor in the air is reduced, the compactness between the composite layer and the silica gel layer is increased, the advanced solidification of the material is avoided, and the reduction of the binding force between the composite layer and the silica gel layer caused by air wrapping is avoided.
The present invention has been described in detail with reference to the embodiments, but the present invention is not limited to the embodiments described above, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.