Conductive carbon nanotube composition and conductive polyurethane roll and method of making same

Abstract

The present application relates to conductive carbon nanotube composition and conductive polyurethane rubber roll and its preparation method, belong to the technical field of rubber roll material.A kind of conductive carbon nanotube composition and conductive polyurethane rubber roll include A component and B component, A component includes: isocyanate, diluent;B component includes: polyol, modified carbon nanotube, leveling agent, chain extender, defoaming agent, antioxidant, catalyst;The present application is first by modified carbon nanotube, let carbon nanotube be combined in polyurethane network structure with the form of covalent bond, avoid carbon nanotube to occur agglomeration, stable construction continuous conductive passage, strengthen the crosslinking structure of polyurethane matrix at the same time, finally realize the synergistic promotion of rubber roll conductive performance and mechanical property.The preparation method of the present application is controllable, and is suitable for industrialized production of conductive polyurethane rubber roll product.

Description

Technical Field

[0001] This invention belongs to the technical field of rubber roller materials, and relates to conductive carbon nanotube compositions, conductive polyurethane rubber rollers, and their preparation methods. Background Technology

[0002] Polyurethane rollers are widely used industrial components in printing, papermaking, metallurgy, and other fields. Their conductivity directly affects the operational stability of equipment and the quality of finished products. In working environments with high static electricity requirements, rollers need to have stable and adjustable volume resistivity to prevent static electricity accumulation from causing printing defects, paper adhesion, and other problems. Current technologies typically achieve conductivity by adding traditional conductive fillers such as carbon black and graphite to the polyurethane matrix. However, these fillers require a high concentration to achieve the target conductivity, which not only increases the overall hardness of the roller, affecting its elasticity and wear resistance, but also easily leads to filler agglomeration, resulting in uneven conductivity at different locations on the roller and a shortened service life. Summary of the Invention

[0003] The purpose of this invention is to provide a conductive carbon nanotube composition and a conductive polyurethane roller, and a method for preparing the same. The preparation method of this invention is simple and controllable, suitable for industrial-scale production. The prepared conductive polyurethane roller has uniform conductivity, long service life, and can meet the needs of industrial applications with high static electricity requirements.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A conductive carbon nanotube composition and a conductive polyurethane roller, comprising component A and component B in a mass ratio of 1:1.02;

[0006] Component A comprises the following components by weight: 38-42 parts MDI, 18-20 parts HDI, and 18-22 parts diluent;

[0007] Component B comprises the following components by weight: 100-110 parts polyol, 4-6 parts modified carbon nanotubes, 1.2-2.0 parts leveling agent, 5-7 parts chain extender, 0.2-0.4 parts defoamer, 0.3-0.5 parts antioxidant, and 0.1-0.3 parts catalyst.

[0008] As a preferred embodiment of the present invention, the polyol is one or a combination of polyether polyol and polyester polyol. The polyether polyol used in the present invention is PPG-3000, the chain extender is 1,4-butanediol, the defoamer is Evonik TEGO Airex 900, and the antioxidant is any one or a combination of antioxidant 1010, antioxidant 1076, or antioxidant 168.

[0009] As a preferred embodiment of the present invention, the leveling agent is any one or more combinations of polydimethylsiloxane and polymethylalkylsiloxane, and the isocyanate is one or more combinations of TDI, MDI and HDI. The isocyanate used in the embodiments and comparative examples of the present invention is composed of 38-42 parts of MDI and 18-20 parts of HDI.

[0010] As a preferred embodiment of the present invention, the catalyst is composed of dibutyltin dilaurate and triethylenediamine in a mass ratio of 1.2-1.5:0.3-0.5, and the diluent is dimethyl carbonate.

[0011] The preparation of the modified carbon nanotubes includes the following steps:

[0012] 1) Mix carbon nanotubes with silane coupling agent, add to ethanol aqueous solution for ultrasonic dispersion, adjust pH value and heat under reflux, centrifuge to remove solids, wash, and vacuum dry in oven to obtain pretreated carbon nanotubes;

[0013] 2) Add the pretreated carbon nanotubes to pure ethanol, then add MMA, HEA and HEMA phosphate ester in sequence and mix. Add the initiator, keep warm and stir, filter out the solids, wash, and vacuum dry in an oven to obtain modified carbon nanotubes.

[0014] As a preferred embodiment of the present invention, the ultrasonic dispersion time in step 1) is 45-60 min, the pH value is adjusted to 10.0-11.0, the heating and reflux is heated to 65-70℃ and refluxed for 5-6 h, and the vacuum drying is vacuum dried at 80℃ to constant weight.

[0015] As a preferred embodiment of the present invention, the concentration of the ethanol aqueous solution in step 1) is 40 wt%, the mass ratio of the carbon nanotubes, silane coupling agent and ethanol aqueous solution is 10-12:1.6-2.0:80-100, and the silane coupling agent is vinyltrimethoxysilane.

[0016] As a preferred technical solution of the present invention, the initiator in step 2) is an AIBN initiator, and the heat preservation and stirring is to heat to 65-70℃ and stir for 4-5 hours.

[0017] As a preferred embodiment of the present invention, the mass ratio of the pretreated carbon nanotubes, MMA, HEA, HEMA phosphate, initiator and pure ethanol in step 2) is 10.0-10.8: 0.6-0.8: 0.22-0.28: 0.04-0.06: 0.010-0.012: 70-80.

[0018] In a preferred embodiment of the present invention, MMA is methyl methacrylate, HEA is hydroxyethyl acrylate, and HEMA phosphate is hydroxyethyl methacrylate phosphate.

[0019] This invention discloses a method for preparing a conductive carbon nanotube composition and a conductive polyurethane roller, the preparation method comprising the following steps:

[0020] First, put the polyol into the reaction vessel for vacuum dehydration, cool it down to 40℃ and keep it at that temperature. Then, add the modified carbon nanotubes, chain extender, antioxidant, leveling agent, defoamer and catalyst into the vessel in sequence and stir at a constant temperature for 60 minutes. Cool it down to room temperature and turn on the vacuum degassing for 15-20 minutes.

[0021] Add isocyanate to a sealed reactor, heat to 60-70℃ and slowly add diluent while stirring, continue stirring at 60-70℃ for 20-30 minutes for later use.

[0022] Mix components A and B, degas under vacuum for 3-5 minutes, and then inject the mixture into a preheated roller mold for curing to obtain the final product.

[0023] The beneficial effects of this invention are:

[0024] 1. This invention introduces double bonds into carbon nanotubes by pretreating them with a silane coupling agent, and then grafts MMA-HEA-HEMA phosphate copolymer onto the surface of the carbon nanotubes through free radical polymerization. This significantly improves the dispersibility of carbon nanotubes in polyols, prevents agglomeration of carbon nanotubes, and allows carbon nanotubes to stably construct continuous conductive pathways. Only a low amount of these components is needed to meet the conductivity requirements, without increasing the hardness of the rubber roller, thus ensuring the elasticity and wear resistance of the rubber roller.

[0025] 2. The modified carbon nanotubes are covalently bonded to the cross-linked network structure of polyurethane. While strengthening the cross-linked structure, the position of the carbon nanotubes is further fixed, preventing carbon nanotube migration during use and ensuring the long-term stability of the conductivity of the rubber roller. Ultimately, this achieves a synergistic improvement in the conductivity and mechanical properties of the rubber roller.

[0026] 3. The preparation method of the present invention is simple and controllable, suitable for industrial-scale production. The prepared conductive polyurethane roller has uniform conductivity, long service life, and can meet the needs of industrial scenarios with high static electricity requirements. Detailed Implementation

[0027] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0028] Example 1

[0029] A conductive carbon nanotube composition and a conductive polyurethane roller comprise component A and component B in a mass ratio of 1.02:1. Component A comprises, by weight, the following components: 38 parts MDI, 18 parts HDI, and 18 parts diluent; component B comprises, by weight, the following components: 100 parts polyol, 4 parts modified carbon nanotubes, 1.2 parts leveling agent, 5 parts chain extender, 0.2 parts defoamer, 0.3 parts antioxidant, and 0.1 parts catalyst.

[0030] The polyol is PPG-3000, the chain extender is 1,4-butanediol, the defoamer is Evonik TEGOAirex 900, and the antioxidant is antioxidant 1010.

[0031] The leveling agent is polydimethylsiloxane.

[0032] The catalyst is composed of dibutyltin dilaurate and triethylenediamine in a mass ratio of 1.2:0.3, and the diluent is dimethyl carbonate.

[0033] The preparation of the modified carbon nanotubes includes the following steps:

[0034] 1) Carbon nanotubes were mixed with a silane coupling agent and added to a 40 wt% ethanol aqueous solution. The mixture was ultrasonically dispersed for 45 min, the pH was adjusted to 10.0, and the mixture was refluxed at 65 °C for 5 h. The solid was centrifuged, washed, and vacuum dried in an oven at 80 °C to constant weight to obtain pretreated carbon nanotubes. The mass ratio of carbon nanotubes, silane coupling agent, and ethanol aqueous solution was 10:1.6:80, and the silane coupling agent was vinyltrimethoxysilane.

[0035] 2) Add the pretreated carbon nanotubes to pure ethanol, then add MMA, HEA and HEMA phosphate ester in sequence and mix. Add AIBN initiator, heat to 65℃ and stir for 4 hours. Filter out the solid, wash, and dry in an oven at 80℃ under vacuum until constant weight to obtain modified carbon nanotubes.

[0036] The mass ratio of the pretreated carbon nanotubes, MMA, HEA, HEMA phosphate, AIBN initiator, and pure ethanol is 10.0:0.6:0.22:0.04:0.010:70.

[0037] A method for preparing a conductive carbon nanotube composition and a conductive polyurethane roller includes the following steps:

[0038] First, put the polyol into the reaction vessel for vacuum dehydration, cool it down to 40°C and keep it at that temperature. Then, add the modified carbon nanotubes, chain extender, antioxidant, leveling agent, defoamer and catalyst into the vessel in sequence and stir at a constant temperature for 60 minutes. Cool it down to room temperature and turn on the vacuum degassing for 15 minutes.

[0039] Add MDI and HDI into a sealed reactor, heat to 60°C, slowly add diluent while stirring, and continue stirring at 60°C for 20 minutes for later use.

[0040] Mix components A and B, degas under vacuum for 3 minutes, and then inject the mixture into a preheated roller mold for curing to obtain the final product.

[0041] Example 2

[0042] A conductive carbon nanotube composition and a conductive polyurethane roller comprise component A and component B in a mass ratio of 1:1.02. Component A comprises, by weight, the following components: 40 parts MDI, 20 parts HDI, and 20 parts diluent; component B comprises, by weight, the following components: 106 parts polyol, 4.8 parts modified carbon nanotubes, 1.6 parts leveling agent, 6 parts chain extender, 0.3 parts defoamer, 0.4 parts antioxidant, and 0.2 parts catalyst.

[0043] The polyol is PPG-3000, the chain extender is 1,4-butanediol, the defoamer is Evonik TEGOAirex 900, and the antioxidant is antioxidant 1010.

[0044] The leveling agent is polydimethylsiloxane.

[0045] The catalyst is composed of dibutyltin dilaurate and triethylenediamine in a mass ratio of 1.4:0.4, and the diluent is dimethyl carbonate.

[0046] The preparation of the modified carbon nanotubes includes the following steps:

[0047] 1) Carbon nanotubes were mixed with a silane coupling agent and added to a 40 wt% ethanol aqueous solution for ultrasonic dispersion for 50 min. After adjusting the pH to 10.5, the mixture was heated to 68 °C and refluxed for 5.5 h. The solid was centrifuged, washed, and vacuum dried in an oven at 80 °C to constant weight to obtain pretreated carbon nanotubes. The mass ratio of carbon nanotubes, silane coupling agent, and ethanol aqueous solution was 11:1.8:90, and the silane coupling agent was vinyltrimethoxysilane.

[0048] 2) Add the pretreated carbon nanotubes to pure ethanol, then add MMA, HEA and HEMA phosphate ester in sequence and mix. Add AIBN initiator, heat to 68℃ and stir for 4.5h. Filter out the solid, wash, and dry in an oven at 80℃ under vacuum until constant weight to obtain modified carbon nanotubes.

[0049] The mass ratio of the pretreated carbon nanotubes, MMA, HEA, HEMA phosphate, AIBN initiator, and pure ethanol is 10.5:0.7:0.25:0.05:0.011:75.

[0050] A method for preparing a conductive carbon nanotube composition and a conductive polyurethane roller includes the following steps:

[0051] First, put the polyol into the reaction vessel for vacuum dehydration, cool it down to 40°C and keep it at that temperature. Then, add the modified carbon nanotubes, chain extender, antioxidant, leveling agent, defoamer and catalyst into the vessel in sequence and stir at a constant temperature for 60 minutes. Cool it down to room temperature and turn on the vacuum degassing for 18 minutes.

[0052] Add MDI and HDI into a sealed reactor, heat to 65°C, slowly add diluent while stirring, and continue stirring at 65°C for 25 minutes for later use.

[0053] Mix components A and B, degas under vacuum for 4 minutes, and then inject the mixture into a preheated roller mold for curing to obtain the final product.

[0054] Example 3

[0055] A conductive carbon nanotube composition and a conductive polyurethane roller comprise component A and component B in a mass ratio of 1:1.02. Component A comprises, by weight, the following components: 42 parts MDI, 20 parts HDI, and 22 parts diluent; component B comprises, by weight, the following components: 110 parts polyol, 6 parts modified carbon nanotubes, 2.0 parts leveling agent, 7 parts chain extender, 0.4 parts defoamer, 0.5 parts antioxidant, and 0.3 parts catalyst.

[0056] The polyol is PPG-3000, the chain extender is 1,4-butanediol, the defoamer is Evonik TEGOAirex 900, and the antioxidant is antioxidant 1010.

[0057] The leveling agent is polydimethylsiloxane.

[0058] The catalyst is composed of dibutyltin dilaurate and triethylenediamine in a mass ratio of 1.5:0.5, and the diluent is dimethyl carbonate.

[0059] The preparation of the modified carbon nanotubes includes the following steps:

[0060] 1) Carbon nanotubes were mixed with a silane coupling agent and added to a 40 wt% ethanol aqueous solution for ultrasonic dispersion for 60 min. After adjusting the pH to 11.0, the mixture was heated to 70 °C and refluxed for 6 h. The solid was centrifuged, washed, and vacuum dried in an oven at 80 °C to constant weight to obtain pretreated carbon nanotubes. The mass ratio of carbon nanotubes, silane coupling agent, and ethanol aqueous solution was 12:2.0:100, and the silane coupling agent was vinyltrimethoxysilane.

[0061] 2) Add the pretreated carbon nanotubes to pure ethanol, then add MMA, HEA and HEMA phosphate ester in sequence and mix. Add AIBN initiator, heat to 70℃ and stir for 5h. Filter out the solid, wash, and dry in an oven at 80℃ under vacuum until constant weight to obtain modified carbon nanotubes.

[0062] The mass ratio of the pretreated carbon nanotubes, MMA, HEA, HEMA phosphate, AIBN initiator, and pure ethanol is 10.8:0.8:0.28:0.06:0.012:80.

[0063] A method for preparing a conductive carbon nanotube composition and a conductive polyurethane roller includes the following steps:

[0064] First, put the polyol into the reaction vessel for vacuum dehydration, cool it down to 40°C and keep it at that temperature. Then, add the modified carbon nanotubes, chain extender, antioxidant, leveling agent, defoamer and catalyst into the vessel in sequence and stir at a constant temperature for 60 minutes. Cool it down to room temperature and turn on the vacuum degassing for 20 minutes.

[0065] Add MDI and HDI into a sealed reactor, heat to 70°C, slowly add diluent while stirring, and continue stirring at 70°C for 30 minutes for later use.

[0066] Mix components A and B, degas under vacuum for 5 minutes, and then inject the mixture into a preheated roller mold for curing to obtain the final product.

[0067] Comparative Example 1

[0068] The difference from Example 2 is that Comparative Example 1 uses MMA instead of HEA.

[0069] Comparative Example 2

[0070] The difference between Comparative Example 2 and Example 2 is that MMA was used instead of HEMA phosphate.

[0071] Comparative Example 3

[0072] Compared with Example 2, the difference is that Comparative Example 3 does not perform step 1) and uses carbon nanotubes instead of pretreated carbon nanotubes.

[0073] The finished products obtained by curing Examples 1-3 and Comparative Examples 1-3 were subjected to the following performance tests:

[0074] Volume resistivity: GB / T1410-2006; Shore A hardness: GB / T531.1-2008; Tensile strength and elongation at break: GB / T528-2009.

[0075] Table 1

[0076]

[0077] As shown in Table 1, the conductive polyurethane roller prepared by this invention has a lower volume resistivity and better conductivity compared to the comparative example. It also has more outstanding mechanical properties. This indicates that the modification method of this invention effectively improves the dispersion and compatibility of carbon nanotubes in the polyurethane matrix, thereby simultaneously improving the conductivity and mechanical properties of the roller and meeting the requirements for high-performance conductive rollers.

[0078] This invention first modifies carbon nanotubes using a silane coupling agent, then further modifies them by grafting MMA, HEA, and HEMA phosphate esters onto the carbon nanotubes. The introduced active groups, such as hydroxyl and phosphate ester groups, react with the isocyanate groups of the polyurethane matrix, allowing the carbon nanotubes to covalently bind within the polyurethane network structure. This prevents carbon nanotube aggregation, stably constructs a continuous conductive pathway, and simultaneously strengthens the cross-linked structure of the polyurethane matrix, ultimately achieving a synergistic improvement in the conductivity and mechanical properties of the rubber roller. The preparation method of this invention is process-controllable and suitable for industrial-scale production of conductive polyurethane rubber rollers.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A conductive carbon nanotube composition and a conductive polyurethane roller, characterized in that, It includes component A and component B in a mass ratio of 1:1.

02. Component A includes the following components by weight: 46-62 parts isocyanate and 18-22 parts diluent. Component B comprises the following components by weight: 100-110 parts polyol, 4-6 parts modified carbon nanotubes, 1.2-2.0 parts leveling agent, 5-7 parts chain extender, 0.2-0.4 parts defoamer, 0.3-0.5 parts antioxidant, and 0.1-0.3 parts catalyst; The preparation of the modified carbon nanotubes includes the following steps: 1) Mix carbon nanotubes with silane coupling agent, add to ethanol aqueous solution for ultrasonic dispersion, adjust pH value and heat under reflux, centrifuge to remove solids, wash, and vacuum dry in oven to obtain pretreated carbon nanotubes; 2) Add the pretreated carbon nanotubes to pure ethanol, then add MMA, HEA and HEMA phosphate ester in sequence and mix. Add the initiator, keep warm and stir, filter out the solids, wash, and vacuum dry in an oven to obtain modified carbon nanotubes.

2. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: The polyol is one or a combination of polyether polyol and polyester polyol, the chain extender is 1,4-butanediol, and the antioxidant is any one or a combination of antioxidant 1010, antioxidant 1076, or antioxidant 168.

3. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: The leveling agent is any one or more combinations of polydimethylsiloxane and polymethylalkylsiloxane, and the isocyanate is one or more combinations of TDI, MDI and HDI.

4. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: The catalyst is composed of dibutyltin dilaurate and triethylenediamine in a mass ratio of 1.2-1.5:0.3-0.5, and the diluent is dimethyl carbonate.

5. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: Step 1) The ultrasonic dispersion time is 45-60 min, the pH value is adjusted to 10.0-11.0, the heating and reflux is heated to 65-70℃ and refluxed for 5-6 h, and the vacuum drying is vacuum dried at 80℃ to constant weight.

6. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: Step 1) The concentration of the ethanol aqueous solution is 40 wt%, and the mass ratio of the carbon nanotubes, silane coupling agent and ethanol aqueous solution is 10-12:1.6-2.0:80-100. The silane coupling agent is vinyltrimethoxysilane.

7. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: Step 2) The initiator is AIBN initiator, and the heat preservation and stirring is to heat to 65-70℃ and stir for 4-5 hours.

8. The conductive carbon nanotube composition and conductive polyurethane roller according to claim 1, characterized in that: In step 2), the mass ratio of the pretreated carbon nanotubes, MMA, HEA, HEMA phosphate, initiator and pure ethanol is 10.0-10.8: 0.6-0.8: 0.22-0.28: 0.04-0.06: 0.010-0.012: 70-80.

9. A method for preparing the conductive carbon nanotube composition and conductive polyurethane roller according to any one of claims 1-8, characterized in that, The preparation method includes the following steps: First, put the polyol into the reaction vessel for vacuum dehydration, cool it down to 40℃ and keep it at that temperature. Then, add the modified carbon nanotubes, chain extender, antioxidant, leveling agent, defoamer and catalyst into the vessel in sequence and stir at a constant temperature for 60 minutes. Cool it down to room temperature and turn on the vacuum degassing for 15-20 minutes. Add isocyanate to a sealed reactor, heat to 60-70℃ and slowly add diluent while stirring, continue stirring at 60-70℃ for 20-30 minutes for later use; Mix components A and B, degas under vacuum for 3-5 minutes, and then inject the mixture into a preheated roller mold for curing to obtain the final product.

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