A high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material and its preparation process

Abstract

The present invention relates to the technical field of silicone rubber cable materials, and discloses a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material and its preparation process, which includes 65-74 parts of silicone rubber, 4-15 parts of hyperbranched organosilicon polyimide, 12-14 parts of carbon black, 3.5-4.5 parts of zinc oxide, and 1.2-1.5 parts of sulfur; in the present invention, silicone rubber is used as the matrix of the cable sheath material, and hyperbranched organosilicon polyimide is added. Its molecular chain contains siloxane structural units, and there is good compatibility and affinity with silicone rubber containing polysiloxane molecular chains, thereby improving the interfacial compatibility between hyperbranched organosilicon polyimide and silicone rubber, playing a good reinforcing role, significantly improving the hardness, tensile properties, and initial thermal decomposition temperature of the silicone rubber sheath material, and the abrasion value is significantly reduced, showing better mechanical strength, wear resistance, and high-temperature resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber cable materials, and specifically to a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material and its preparation process. Background Art

[0002] The sheath material is an important part of wire and cable, and it is required that the sheath material has good heat resistance, mechanical strength, wear resistance and other properties. Mainly there are polyvinyl chloride, polyethylene, silicone rubber, ethylene propylene diene monomer rubber, etc. Among them, silicone rubber has good temperature resistance, strong weather resistance and excellent insulation performance, and is widely used in the fields of wire and cable sheath materials, etc. Traditional silicone rubber sheath materials have problems such as low mechanical strength and poor wear resistance, so it is necessary to reinforce silicone rubber.

[0003] Polyimide is a kind of polymer containing imide ring structure, which has the advantages of large mechanical strength, excellent insulation performance, high wear resistance and strong high-temperature resistance. It has good applications in materials such as plastics and rubbers. Patent CN106118065B discloses an intumescent flame-retardant silicone rubber and its preparation method, using an intumescent flame retardant composed of ammonium polyphosphate, pentaerythritol tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and melamine-polyimide supramolecular network composite material, which can improve the flame retardant performance, mechanical performance and thermal stability performance of silicone rubber. However, the compatibility between polyimide and silicone rubber is not good, and the improvement of its mechanical properties is limited when added to silicone rubber. Summary of the Invention

[0004] The present invention solves the problems of low wear resistance, strength and other properties of silicone rubber wire and cable sheath materials.

[0005] Technical Solution: A high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material, comprising the following components in parts by weight: 65 - 74 parts of silicone rubber, 4 - 15 parts of hyperbranched organosilicon polyimide, 12 - 14 parts of carbon black, 3.5 - 4.5 parts of zinc oxide, 1.2 - 1.5 parts of sulfur, 1.2 - 1.8 parts of accelerator DM (2,2'-dithiobenzothiazole), 1.4 - 1.8 parts of antioxidant N-phenyl-2-naphthylamine.

[0006] The preparation process of hyperbranched organosilicon polyimide is: adding N,N-dimethylformamide solvent, hydroxy organosilicon phenylimide monomer, diisocyanate compound into a flask, introducing nitrogen, dropping dibutyltin dilaurate, carrying out a polymerization reaction, adding ethanol to dilute the solution, after suction filtration, washing the precipitate with ethanol, and drying to obtain hyperbranched organosilicon polyimide.

[0007] Preferably, by weight parts, the dosage of the hydroxy organosilicon phenylimide monomer is 100 parts, the diisocyanate compound is 48 - 63 parts, and the dibutyltin dilaurate is 1.2 - 1.8 parts.

[0008] Preferably, the diisocyanate compound is toluene - 2,4 - diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate.

[0009] Preferably, the temperature of the polymerization reaction is 55 - 75 °C, and the time is 3 - 5 h.

[0010] Preferably, the preparation process of the hydroxy organosilicon phenylimide monomer is as follows:

[0011] (1) Add polyethylene glycol solvent, 100 parts by weight of 4 - hydroxyphthalic anhydride, 70 - 75 parts by weight of 4 - aminobenzaldehyde, and 7 - 8 parts by weight of boric acid into a flask, react at 40 - 60 °C for 3 - 5 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain an intermediate.

[0012] (2) Add methanol, 210 - 230 parts by weight of the intermediate, and 100 parts by weight of 1,3 - bis(3 - aminopropyl)-1,1,3,3 - tetramethyldisiloxane into a flask, heat up to 60 - 65 °C, carry out reflux condensation reaction for 6 - 10 h, cool to room temperature, add 34 - 38 parts by weight of sodium borohydride, continue to react for 3 - 4 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain the hydroxy organosilicon phenylimide monomer.

[0013] Preferably, the preparation process of the high - strength, wear - resistant and high - temperature resistant wire and cable sheath material is as follows: Put silicone rubber, hyperbranched organosilicon polyimide, carbon black, zinc oxide, sulfur, accelerator, and antioxidant into an open mill for mixing; then carry out thin pass and sheet down; finally, carry out vulcanization in a flat vulcanizer to obtain the high - strength, wear - resistant and high - temperature resistant wire and cable sheath material.

[0014] Preferably, the roller temperature during mixing in the open mill is 200 - 210 °C, and the mixing time is 10 - 20 min; the pressure during vulcanization in the flat vulcanizer is 10 - 15 MPa, the temperature is 150 - 165 °C, and the time is 20 - 30 min.

[0015] Technical effect: In the reaction system of polyethylene glycol and boric acid, 4-hydroxyphthalic anhydride and 4-aminobenzaldehyde are subjected to imidization reaction to obtain an intermediate, which is subjected to Schiff base condensation reaction with 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane and reduced by sodium borohydride to obtain a hydroxyl organic silicon phenylimide monomer containing two hydroxyl groups and two imino groups. Then, it is subjected to hyperbranched polymerization reaction with a diisocyanate compound such as hexamethylene diisocyanate to obtain a novel hyperbranched organosilicon polyimide.

[0016] In the present invention, silicone rubber is used as the matrix of the cable sheath material, and hyperbranched organosilicon polyimide is added. Its molecular chain contains a siloxane structural unit, and there is good compatibility and affinity with the silicone rubber containing a polysiloxane molecular chain, thereby improving the interfacial compatibility between the hyperbranched organosilicon polyimide and the silicone rubber. The polyimide polymer has high strength, high hardness, strong wear resistance, strong high-temperature resistance, and contains a hyperbranched dendritic molecular chain, which forms a physical molecular chain entanglement with the silicone rubber. When subjected to an external force, it can absorb and dissipate stress, playing a good reinforcing role, significantly improving the hardness, tensile properties, initial thermal decomposition temperature and carbon residue content of the silicone rubber sheath material, and significantly reducing the abrasion value, showing better mechanical strength, wear resistance and high-temperature resistance. Specific embodiments

[0017] The preferred embodiments of the present invention will be described in detail below in conjunction with the examples. It should be understood that the following examples are given only for the purpose of illustration and are not used to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0018] Example 1

[0019] (1) Add 35 mL of polyethylene glycol 600 solvent, 6 g of 4-hydroxyphthalic anhydride, 4.2 g of 4-aminobenzaldehyde, and 0.48 g of boric acid to a flask, react at 50 °C for 3 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain an intermediate. The reaction formula is as follows:

[0020]

[0021] (2) Add 80 mL of methanol, 1.05 g of the intermediate, and 5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to a flask, heat to 65 °C, reflux and react for 6 h, cool to room temperature, add 1.8 g of sodium borohydride, and continue to react for 4 h. Distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain a hydroxyl organic silicon phenylimide monomer. The reaction formula is as follows:

[0022]

[0023] (3) Add 150 mL of N,N-dimethylformamide solvent, 10 g of hydroxy organosilicon phenylimide monomer, 4.8 g of hexamethylene diisocyanate into the flask, introduce nitrogen, dropwise add 0.18 g of dibutyltin dilaurate, raise the temperature to 75 °C, carry out the polymerization reaction for 3 h, add ethanol to dilute the solution, after suction filtration, wash the precipitate with ethanol, and dry it to obtain hyperbranched organosilicon polyimide. The reaction formula is:

[0024]

[0025] (4) Place 74 g of silicone rubber, 4 g of hyperbranched organosilicon polyimide, 14 g of carbon black, 3.5 g of zinc oxide, 1.5 g of sulfur, 1.4 g of accelerator DM, and 1.8 g of antioxidant N-phenyl-2-naphthylamine on the open mill, control the roll temperature at 200 °C, and carry out mixing for 20 min; then carry out thin passing and sheet down; finally, carry out vulcanization in a flat vulcanizer for 30 min, control the pressure at 12 MPa and the temperature at 150 °C; obtain the high-strength, wear-resistant and high-temperature resistant wire and cable sheath material.

[0026] Example 2

[0027] (1) Add 40 mL of polyethylene glycol 600 solvent, 6 g of 4-hydroxyphthalic anhydride, 4.5 g of 4-aminobenzaldehyde, and 0.48 g of boric acid into the flask, react at 60 °C for 3 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain the intermediate.

[0028] (2) Add 100 mL of methanol, 1.15 g of the intermediate, and 5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane into the flask, raise the temperature to 60 °C, carry out reflux condensation reaction for 10 h, cool to room temperature, add 1.9 g of sodium borohydride, and continue to react for 3 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain the hydroxy organosilicon phenylimide monomer.

[0029] (3) Add 200 mL of N,N-dimethylformamide solvent, 10 g of hydroxy organosilicon phenylimide monomer, 5.1 g of toluene-2,4-diisocyanate into the flask, introduce nitrogen, dropwise add 0.15 g of dibutyltin dilaurate, raise the temperature to 55 °C, carry out the polymerization reaction for 5 h, add ethanol to dilute the solution, after suction filtration, wash the precipitate with ethanol, and dry it to obtain hyperbranched organosilicon polyimide.

[0030] (4) Put 68 g of silicone rubber, 10 g of hyperbranched organosilicon polyimide, 14 g of carbon black, 3.5 g of zinc oxide, 1.2 g of sulfur, 1.2 g of accelerator DM, and 1.8 g of antioxidant N-phenyl-2-naphthylamine into an open mill, control the roll temperature at 200 °C, and carry out mixing for 20 min; then carry out thin passing and sheeting; finally, carry out vulcanization in a flat vulcanizer for 20 min, control the pressure at 15 MPa and the temperature at 160 °C; obtain a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material.

[0031] Example 3

[0032] (1) Add 35 mL of polyethylene glycol 600 solvent, 6 g of 4-hydroxyphthalic anhydride, 4.2 g of 4-aminobenzaldehyde, and 0.458 g of boric acid to a flask, react at 40 °C for 5 h, distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain an intermediate.

[0033] (2) Add 80 mL of methanol, 1.05 g of the intermediate, and 5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to a flask, heat up to 65 °C, carry out reflux condensation reaction for 8 h, cool to room temperature, add 1.7 g of sodium borohydride, and continue to react for 4 h. Distill the solution under reduced pressure, wash with deionized water, and recrystallize the product in ethanol to obtain a hydroxyl organosilicon phenylimide monomer.

[0034] (3) Add 200 mL of N,N-dimethylformamide solvent, 10 g of the hydroxyl organosilicon phenylimide monomer, 6.3 g of isophorone diisocyanate to a flask, introduce nitrogen, dropwise add 0.12 g of dibutyltin dilaurate, heat up to 70 °C, and carry out polymerization reaction for 3 h. Dilute the solution with ethanol, filter by suction, wash the precipitate with ethanol, and dry to obtain hyperbranched organosilicon polyimide.

[0035] (4) Put 65 g of silicone rubber, 15 g of hyperbranched organosilicon polyimide, 12 g of carbon black, 4.5 g of zinc oxide, 1.2 g of sulfur, 1.8 g of accelerator DM, and 1.4 g of antioxidant N-phenyl-2-naphthylamine into an open mill, control the roll temperature at 210 °C, and carry out mixing for 10 min; then carry out thin passing and sheeting; finally, carry out vulcanization in a flat vulcanizer for 30 min, control the pressure at 10 MPa and the temperature at 165 °C; obtain a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material.

[0036] Comparative Example 1

[0037] The difference between this comparative example and Example 1 is that hyperbranched organosilicon polyimide is not added.

[0038] (1) Put 74 g of silicone rubber, 14 g of carbon black, 3.5 g of zinc oxide, 1.5 g of sulfur, 1.4 g of accelerator DM, and 1.8 g of antioxidant N-phenyl-2-naphthylamine into an open mill, control the roll temperature at 200 °C, and carry out mixing for 20 min; then carry out thin passing and sheet cutting; finally, carry out vulcanization in a flat vulcanizer for 30 min, control the pressure at 12 MPa and the temperature at 150 °C; obtain a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material.

[0039] Comparative Example 2

[0040] The difference between this comparative example and Example 1 is that when preparing the hydroxyphenylimide monomer, p-phenylenediamine is used instead of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane.

[0041] (1) Add 80 mL of methanol, 1.05 g of intermediate (with the same preparation process as in Example 1), and 5 g of p-phenylenediamine to a flask, heat up to 65 °C, carry out condensation reflux reaction for 6 h, cool to room temperature, add 1.8 g of sodium borohydride, continue the reaction for 4 h, carry out reduced pressure distillation on the solution, wash with deionized water, and recrystallize the product in ethanol to obtain the hydroxyphenylimide monomer. The reaction formula is as follows:

[0042]

[0043] (2) Add 150 mL of N,N-dimethylformamide solvent, 10 g of hydroxyphenylimide monomer, 4.8 g of hexamethylene diisocyanate to a flask, introduce nitrogen, dropwise add 0.18 g of dibutyltin dilaurate, heat up to 75 °C, carry out polymerization reaction for 3 h, add ethanol to dilute the solution, after filtration, wash the precipitate with ethanol, and dry to obtain hyperbranched polyimide.

[0044] (3) Put 74 g of silicone rubber, 4 g of hyperbranched polyimide, 14 g of carbon black, 3.5 g of zinc oxide, 1.5 g of sulfur, 1.4 g of accelerator DM, and 1.8 g of antioxidant N-phenyl-2-naphthylamine into an open mill, control the roll temperature at 200 °C, and carry out mixing for 20 min; then carry out thin passing and sheet cutting; finally, carry out vulcanization in a flat vulcanizer for 30 min, control the pressure at 12 MPa and the temperature at 150 °C; obtain a high-strength, wear-resistant and high-temperature-resistant wire and cable sheath material.

[0045] Comparative Example 3

[0046] The difference between this comparative example and Example 1 is that when preparing the hydroxyorganosiliconphenylimide precursor, reduction is not carried out with sodium borohydride.

[0047] (1) Add 80 mL of methanol, 1.05 g of intermediate (prepared by the same process as in Example 1), and 5 g of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane to a flask. Heat the mixture to 65 °C and reflux for 6 h. Cool to room temperature, distill the solution under reduced pressure, wash with acetone, and recrystallize the product from ethanol to obtain a hydroxy organosilicon phenylimide precursor. The structural formula is as follows:

[0048]

[0049] (2) Add 150 mL of N,N-dimethylformamide solvent, 10 g of hydroxy organosilicon phenylimide precursor, 4.8 g of hexamethylene diisocyanate to a flask, introduce nitrogen, add 0.18 g of dibutyltin dilaurate dropwise, heat to 75 °C, and carry out a polymerization reaction for 3 h. Dilute the solution with ethanol, filter by suction, wash the precipitate with ethanol, and dry to obtain an organosilicon polyimide.

[0050] (3) Place 74 g of silicone rubber, 4 g of organosilicon polyimide, 14 g of carbon black, 3.5 g of zinc oxide, 1.5 g of sulfur, 1.4 g of accelerator DM, and 1.8 g of antioxidant N-phenyl-2-naphthylamine in an open mill, control the roll temperature at 200 °C, and carry out mixing for 20 min; then carry out thin passing and sheeting; finally, vulcanize in a flat vulcanizer for 30 min, control the pressure at 12 MPa and the temperature at 150 °C; to obtain a high-strength, wear-resistant, and high-temperature-resistant wire and cable sheath material.

[0051] Use a universal material testing machine to test the tensile properties of the sheath material according to the method of GB / T 528-2009. Use a Shore hardness tester to test the Shore A hardness according to the method of GB / T 531.1-2008. Use an abrasion tester to test the wear resistance according to the method of GB / T 1689-2014. The test results are shown in the following table.

[0052]

[0053] Use a thermogravimetric analyzer to test the thermal properties of the sheath material. In the nitrogen range, heat from room temperature to 800 °C at a heating rate of 10 °C / min. The test results are shown in the following table.

[0054]

[0055] After testing, hyperbranched organosilicon polyimide is added to the silicone rubber sheath materials of Examples 1, 2, and 3. Its molecular chain contains siloxane structural units, and there is good compatibility and affinity with the silicone rubber containing polysiloxane molecular chains, thereby improving the interfacial compatibility between the hyperbranched organosilicon polyimide and the silicone rubber. The polyimide polymer has high strength, high hardness, strong wear resistance, and strong high-temperature resistance, and contains hyperbranched dendritic molecular chains, which form physical molecular chain entanglement with the silicone rubber. When subjected to external forces, it can absorb and dissipate stress, playing a very good reinforcing role. Compared with Comparative Example 1, the hardness, tensile properties, initial thermal decomposition temperature, and char residue content of the silicone rubber sheath materials of Examples 1, 2, and 3 are significantly improved, and the abrasion value is significantly reduced, showing better mechanical strength, wear resistance, and high-temperature resistance.

[0056] In Comparative Example 2, the phenylimide monomer was obtained by reacting an intermediate with p-phenylenediamine, and then polymerized with hexamethylene diisocyanate. The obtained hyperbranched polyimide does not contain siloxane structural units, has very poor compatibility with silicone rubber, and has poor dispersion in the silicone rubber sheath material. The improvement in properties such as the hardness, tensile strength, and thermal decomposition temperature of the silicone rubber sheath material is relatively low, and the abrasion value is higher than that of Example 1, with poor wear resistance.

[0057] The hydroxy organosilicon phenylimide precursor of Comparative Example 3 only contains two hydroxyl groups and does not contain two imino groups, and cannot undergo hyperbranched polymerization reaction with hexamethylene diisocyanate. The obtained organosilicon polyimide has a linear structure, not a hyperbranched dendritic structure, and has poor reinforcing effect on silicone rubber. Its properties such as hardness, tensile strength, and thermal decomposition temperature are lower than those of Example 1.

[0058] The above is only the preferred specific implementation manner of the present invention; however, the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the present invention and its improved concept, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A high-strength, wear-resistant and high-temperature resistant wire and cable sheath material, characterized in that: The wire and cable sheath material comprises the following components in parts by weight: 65-74 parts of silicone rubber, 4-15 parts of hyperbranched organosilicon polyimide, 12-14 parts of carbon black, 3.5-4.5 parts of zinc oxide, 1.2-1.5 parts of sulfur, 1.2-1.8 parts of accelerator, and 1.4-1.8 parts of antioxidant; The preparation process of the hyperbranched organosilicon polyimide is as follows: N,N-dimethylformamide solvent, hydroxyl organosilicon phenylimide monomer, and diisocyanate compound are added into a flask, nitrogen is introduced, dibutyltin dilaurate is added dropwise, polymerization reaction is carried out, ethanol is added into the solution for dilution, suction filtration is performed, washing is performed, and drying is performed to obtain the hyperbranched organosilicon polyimide; The hydroxyl organosilicon phenylimide monomer has the following structural formula (I): Formula (I).

2. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 1, characterized in that: In terms of weight, the usage of the hydroxyl organosilicon phenylimide monomer is 100 parts, the usage of the diisocyanate compound is 48-63 parts, and the usage of the dibutyltin dilaurate is 1.2-1.8 parts.

3. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 2, characterized in that: The diisocyanate compound is toluene-2,4-diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

4. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 2, characterized in that: The polymerization reaction temperature is 55-75° C. and the reaction time is 3-5 hours.

5. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 2, characterized in that: The preparation process of the hydroxyl organosilicon phenylimide monomer is as follows: (1) Add polyethylene glycol solvent, 100 parts by weight of 4-hydroxyphthalic anhydride, 70-75 parts by weight of 4-aminobenzaldehyde, and 7-8 parts by weight of boric acid into a flask to react, distill the solution under reduced pressure, wash, and recrystallize to obtain an intermediate; (2) Add methanol, the intermediate, and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane into a flask, raise the temperature to 60-65° C., condense and reflux for 6-10 hours, cool to room temperature, add sodium borohydride, continue to react for 3-4 hours, distill the solution under reduced pressure, wash, and recrystallize to obtain a hydroxyl organosilicon phenylimide monomer.

6. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 5, characterized in that: In the step (1), the reaction temperature is 40-60°C and the reaction time is 3-5h.

7. The high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 5, characterized in that: In the above (2), by weight, the amount of 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyldisiloxane is 100 parts, the amount of the intermediate is 210-230 parts, and the amount of sodium borohydride is 34-38 parts.

8. A process for preparing the high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to any one of claims 1 to 7, characterized in that: The preparation process comprises the following steps: placing silicone rubber, hyperbranched organosilicon polyimide, carbon black, zinc oxide, sulfur, accelerator and antioxidant in an open mill for mixing; then thinning and sheeting; and finally vulcanizing in a flat vulcanizer to obtain a high-strength, wear-resistant and high-temperature resistant wire and cable sheath material.

9. The preparation process of the high-strength, wear-resistant and high-temperature resistant wire and cable sheath material according to claim 8, characterized in that: The roller temperature during mixing in the open mill is 200-210° C., and the mixing time is 10-20 min. The pressure during vulcanization in the flat vulcanizing press is 10-15 MPa, the temperature is 150-165° C., and the time is 20-30 min.

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