Phase change compressible silica gel gasket based on additive manufacturing

Abstract

The invention discloses a phase change compressible silica gel gasket based on additive manufacturing, which is prepared from the following ingredients in parts by mass: 40 to 45 parts of methyl vinyl silicone rubber, 1.3 to 1.5 parts of cross-linking agents, 0.8 to 1.0 part of chain extenders, 15 to 20 parts of monofunctional vinyl, 0.05 to 0.1 part of inhibitors, 30 to 35 parts of flame retardants, 3 to 5 parts of phase change microcapsules, 1 to 2 parts of coloring agents and 0.03 to 0.05 part of catalysts. The preparation method of the phase-change compressible silica gel gasket based on additive manufacturing adopts a screw extrusion and ejection layer-by-layer printing mode, and comprises the steps of matrix premixing, functional filler dispersion, slurry preparation, material extrusion, deposition molding and post-treatment. The size of the phase change material can be dynamically changed along with the temperature change; a visual virtual drawing can be generated in advance, parameters can be conveniently adjusted and optimized before production to meet customer requirements, the phase change silica gel compression gasket is produced in a screw extrusion and spraying layer-by-layer printing mode, remote production can be achieved, burrs are avoided, materials are saved, and the method is environmentally friendly and simple.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and in particular to a phase-change compressible silicone gasket based on additive manufacturing. Background Art

[0002] In consumer electronic display devices, silicone rubber gaskets are often used as limit blocks to buffer and protect the plastic frame and glass plate. Generally, silicone rubber materials such as Shin-Etsu silicone KE-951U are used as common solutions. As the ambient temperature and humidity change, the glass plate and the plastic frame are prone to dimensional changes in various scenarios due to the inconsistency of expansion coefficients. However, as a traditional silicone rubber solution, silicone rubber itself is not sensitive to temperature-dependent dimensional changes and does not have variable dimensions. When either of the two exceeds the upper limit of dimensional change, structural failure is likely to occur, that is, there is extrusion of the glass or plastic frame, or inappropriate retraction, which will cause damage to the physical hardware of the assembled display device or structural failure, and ultimately affect the display effect of the terminal device.

[0003] Traditional silicone gaskets are usually produced by compression molding or injection molding, which has problems such as complex processes and low design freedom. Additive manufacturing (3D printing) technology provides the possibility of personalized customization for silicone products, but existing silicone materials are prone to problems such as poor fluidity and unstable curing speed during the printing process. In addition, conventional silicone gaskets have a single function and it is difficult to meet the requirements of cushioning, sealing and thermal management at the same time. In addition, silicone gaskets are produced by mixing slurry in the traditional production process, and the conventional mold opening method is used in the finalization stage. Due to the certain fluidity of silicone polymers, local extrusion deformation and capillary phenomena are prone to occur during the demolding process. The gaskets finally formed have burrs, resulting in unqualified delivery quality. Each pattern requires a separate mold. If the size is not suitable, the mold needs to be scrapped, which is a huge cost and resource waste for both the product and the mold.

[0004] Therefore, the present invention provides a phase-change compressible silicone gasket based on additive manufacturing. By using the phase-change compressible silicone gasket, the position of the limit block can be dynamically adjusted according to the temperature to meet the size changes of the component. It has the property of being compressible / expandable with temperature that traditional silicone rubber itself does not have, and has great technical advantages. It is obviously of great significance to develop a silicone material that has compressibility, phase-change temperature control function and is suitable for additive manufacturing. Summary of the invention

[0005] The purpose of the present invention is to provide a phase-change compressible silicone gasket based on additive manufacturing, so as to obtain a silicone material that has both compressibility and phase-change temperature regulation function and is suitable for additive manufacturing.

[0006] The purpose of the present invention is achieved through the following technical solutions: A phase-change compressible silicone gasket based on additive manufacturing, comprising, by weight, 40-45 parts of methyl vinyl silicone rubber, 1.3-1.5 parts of a cross-linking agent, 0.8-1.0 parts of a chain extender, 15-20 parts of a monofunctional vinyl, 0.05-0.1 parts of an inhibitor, 30-35 parts of a flame retardant, 3-5 parts of a phase-change microcapsule, 1-2 parts of a colorant, and 0.03-0.05 parts of a catalyst.

[0007] Preferably, the crosslinking agent is selected from one or more of polymethylhydrogensiloxane (PMHS), HMS-991, dicumyl peroxide (DCP), and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

[0008] Preferably, the chain extender is selected from one or more of hydroxy-terminated polydimethylsiloxane, α,ω-dihydroxy polydimethylsiloxane, tetramethyl divinyl disiloxane, vinyl silicone oil (vinyl content 0.1%~0.5%), γ-aminopropyl triethoxysilane (KH-550), N-phenyl-γ-aminopropyl trimethoxysilane, and γ-glycidyl ether oxypropyl trimethoxysilane (KH-560).

[0009] Preferably, the monofunctional vinyl group is selected from one of vinyl trimethoxysilane (VTMS), vinyl triethoxysilane (VTES), vinyl methyl dimethoxy silane (VMDMS), vinyl dimethyl methoxy silane (VDMMS), and γ-methacryloxypropyl trimethoxy silane (KH-570).

[0010] Preferably, the inhibitor is selected from one or more of ethynylcyclohexanol (ECH), methylbutynol (MBY), dimethylethynylmethanol (DMA), vinylcyclohexene oxide (VCHO), diethyl maleate, and dibutyltin dilaurate.

[0011] Preferably, the flame retardant is selected from one of aluminum hydroxide (ATH), magnesium hydroxide (MH), nano-silicon dioxide, layered double hydroxide (LDH), and carbon nanotube (CNT).

[0012] Preferably, the catalyst is selected from one of platinum-divinyltetramethyldisiloxane complex and RhCl(PPh3)3.

[0013] Preferably, the phase change microcapsules are paraffin core-shell microcapsules, which consist of an inner core and an outer shell, wherein the inner core is selected from one of n-octadecane, n-eicosane and paraffin, and the outer shell is selected from one of melamine-formaldehyde resin (MF), silica and polymethyl methacrylate (PMMA).

[0014] Preferably, the colorant is selected from titanium dioxide (TiO2), red iron oxide, and black iron oxide, and the particle size of the colorant is 0.5-5 μm.

[0015] The present application also claims a method for preparing the above-mentioned phase-change compressible silicone gasket based on additive manufacturing, comprising the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir for 30 to 45 minutes at 55 to 65°C and vacuum degree -0.095 MPa at a speed of 300 to 500 rpm to obtain a matrix premix system; S2. Functional filler dispersion: flame retardant and phase change microcapsules are sequentially added to the matrix premix system, and a three-roll mill is used to disperse the system to obtain a dispersion system; a colorant is added to the dispersion system, and an ultrasonic disperser is used to process the system at 500 W and 20 kHz for 15 to 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 5-8 minutes; slowly dropwise add a crosslinking agent and stir for 15-20 minutes; finally add a catalyst and stir for 5-8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1 MPa and 25°C for 30 minutes, and control the viscosity to 5000-8000 mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.1~0.4mm. The moving speed and extrusion amount of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 1~50 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 0.02mm~20mm, and the printing speed is 5mm / s~100mm / s; S6. Post-processing: After printing, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket. This improves the appearance and mechanical properties of the model and adds other functionality.

[0016] Due to the application of the above technical solution, the present invention has the following beneficial effects compared with the prior art: 1. The phase change material added in the present invention with special formula design can dynamically change size with temperature change, sensitively follow the size change of components, have multi-functions such as heat conduction, very good elasticity and thermal stability; thermoplastic elastomer can ensure the initial thickness and elasticity under high and low temperature cycle; no oil seepage and very low small molecule volatility; 2. The additive manufacturing of the present invention can generate visual virtual drawings in advance, which is convenient for adjusting and optimizing parameters before production to meet customer needs. Once the traditional mold is opened, it cannot be modified and can also be transferred to other terminals for off-site production; 3. The quality and appearance of the materials produced by additive manufacturing of the present invention are controllable. The phase change silicone compression gasket is produced by screw extrusion + spraying layer by layer printing, which can realize off-site production, no burrs, save materials, do not require additional cleaning, is environmentally friendly and simple, greatly saves production costs, and can also be expanded to the production of other polymer materials; 4. The present invention can realize phase change compressibility, intelligent dynamic size change, and has a unique silicone gasket compression ratio curve. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, some of the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be made based on these drawings without paying any creative work.

[0018] Figure 1 This is a schematic diagram of screw extrusion + spraying layer-by-layer printing in Example 1 of the present invention; Figure 2 This is a compression ratio curve diagram of the phase-change compressible silica gel gasket of Example 1 of the present invention; Among them, 1- screw, 2- nozzle, 3- slurry. DETAILED DESCRIPTION

[0019] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, a specific implementation scheme is now described in detail.

[0020] The present invention is further described below in conjunction with the embodiments, but the present invention is not limited to the following embodiments. The implementation conditions used in the embodiments can be further adjusted according to the different requirements of specific use, and the implementation conditions not indicated are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0021] Example 1 See attached Figure 1 And attached Figure 2, this embodiment provides a phase-change compressible silicone gasket based on additive manufacturing, which includes, by mass, 42 parts of methyl vinyl silicone rubber, 1.4 parts of a cross-linking agent, 0.9 parts of a chain extender, 18 parts of a monofunctional vinyl, 0.08 parts of an inhibitor, 32 parts of a flame retardant, 4 parts of a phase-change microcapsule, 2 parts of a colorant, and 0.04 parts of a catalyst; The cross-linking agent is polymethylhydrogensiloxane (PMHS); The chain extender is hydroxyl-terminated polydimethylsiloxane; The monofunctional vinyl group is vinyl trimethoxysilane (VTMS); The inhibitor is ethynylcyclohexanol (ECH); The flame retardant is aluminum hydroxide (ATH); The catalyst is a platinum-divinyltetramethyldisiloxane complex; The phase change microcapsule is a paraffin core-shell microcapsule, which is composed of a core and an outer shell, wherein the core is paraffin, the outer shell is silicon dioxide, and the phase change microcapsule is a paraffin@SiO2 phase change microcapsule; The colorant is red iron oxide, and the particle size of the colorant is 0.5-5 μm; The method for preparing the phase-change compressible silicone gasket based on additive manufacturing comprises the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir at 400 rpm for 40 minutes at 60° C. and vacuum degree -0.095 MPa to obtain a matrix premix system; S2, functional filler dispersion: flame retardant and phase change microcapsule are added to the matrix premix system in sequence, and dispersed by a three-roll mill to obtain a dispersed system; colorant is added to the dispersed system, and an ultrasonic disperser is used to treat at 500W, 20kHz for 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 6 minutes; slowly dropwise add a crosslinking agent and stir for 18 minutes; finally add a catalyst and stir for 8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1MPa and 25°C for 30 minutes, and control the viscosity to 5500-5800mPa·s; S4, material extrusion: the slurry (3) is fed into the screw (1) of the printer and extruded into the nozzle. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle (2) has a diameter of 0.3 mm. The movement speed and extrusion volume of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 15 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 2mm, and the printing speed is 20mm / s; S6, post-processing: after printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket; The compression ratio curve of the phase-change compressible silicone gasket prepared in this embodiment is shown in the attached Figure 2 , showing the change curves at 30℃, 40℃, 50℃ and 60℃ respectively.

[0022] Example 2 This embodiment provides a phase-change compressible silicone gasket based on additive manufacturing, which includes, by weight, 45 parts of methyl vinyl silicone rubber, 1.3 parts of a cross-linking agent, 1.0 parts of a chain extender, 15 parts of a monofunctional vinyl, 0.06 parts of an inhibitor, 30 parts of a flame retardant, 5 parts of a phase-change microcapsule, 2 parts of a colorant, and 0.04 parts of a catalyst; The cross-linking agent is polymethylhydrogensiloxane (PMHS); The chain extender is hydroxyl-terminated polydimethylsiloxane; The monofunctional vinyl group is vinyl trimethoxysilane (VTMS); The inhibitor is ethynylcyclohexanol (ECH); The flame retardant is aluminum hydroxide (ATH); The catalyst is a platinum-divinyltetramethyldisiloxane complex; The phase change microcapsule is a paraffin core-shell microcapsule, which is composed of a core and an outer shell, wherein the core is paraffin, the outer shell is silicon dioxide, and the phase change microcapsule is a paraffin@SiO2 phase change microcapsule; The colorant is red iron oxide, and the particle size of the colorant is 0.5-5 μm; The method for preparing the phase-change compressible silicone gasket based on additive manufacturing comprises the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir at 400 rpm for 40 minutes at 60° C. and vacuum degree -0.095 MPa to obtain a matrix premix system; S2, functional filler dispersion: flame retardant and phase change microcapsule are added to the matrix premix system in sequence, and dispersed by a three-roll mill to obtain a dispersed system; colorant is added to the dispersed system, and an ultrasonic disperser is used to treat at 500W, 20kHz for 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 6 minutes; slowly dropwise add a crosslinking agent and stir for 18 minutes; finally add a catalyst and stir for 8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1MPa and 25°C for 30 minutes, and control the viscosity to 5500-5800mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.3mm. The moving speed and extrusion amount of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 15 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 2mm, and the printing speed is 20mm / s; S6. Post-processing: After printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket.

[0023] Example 3 This embodiment provides a phase-change compressible silicone gasket based on additive manufacturing, which includes, by weight, 40 parts of methyl vinyl silicone rubber, 1.5 parts of a cross-linking agent, 0.8 parts of a chain extender, 20 parts of a monofunctional vinyl, 0.08 parts of an inhibitor, 35 parts of a flame retardant, 3 parts of a phase-change microcapsule, 2 parts of a colorant, and 0.04 parts of a catalyst; The cross-linking agent is polymethylhydrogensiloxane (PMHS); The chain extender is hydroxyl-terminated polydimethylsiloxane; The monofunctional vinyl group is vinyl trimethoxysilane (VTMS); The inhibitor is ethynylcyclohexanol (ECH); The flame retardant is aluminum hydroxide (ATH); The catalyst is a platinum-divinyltetramethyldisiloxane complex; The phase change microcapsule is a paraffin core-shell microcapsule, which is composed of a core and an outer shell, wherein the core is paraffin, the outer shell is silicon dioxide, and the phase change microcapsule is a paraffin@SiO2 phase change microcapsule; The colorant is red iron oxide, and the particle size of the colorant is 0.5-5 μm; The method for preparing the phase-change compressible silicone gasket based on additive manufacturing comprises the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir at 400 rpm for 40 minutes at 60° C. and vacuum degree -0.095 MPa to obtain a matrix premix system; S2, functional filler dispersion: flame retardant and phase change microcapsule are added to the matrix premix system in sequence, and dispersed by a three-roll mill to obtain a dispersed system; colorant is added to the dispersed system, and an ultrasonic disperser is used to treat at 500W, 20kHz for 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 6 minutes; slowly dropwise add a crosslinking agent and stir for 18 minutes; finally add a catalyst and stir for 8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1MPa and 25°C for 30 minutes, and control the viscosity to 5500-5800mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.3mm. The moving speed and extrusion amount of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 15 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 2mm, and the printing speed is 20mm / s; S6. Post-processing: After printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket.

[0024] Comparative Example 1 This comparative example provides a silicone gasket, which includes, by mass, 42 parts of methyl vinyl silicone rubber, 1.4 parts of a cross-linking agent, 0.9 parts of a chain extender, 18 parts of a monofunctional vinyl, 0.08 parts of an inhibitor, 32 parts of a flame retardant, 0 parts of a phase change microcapsule, 2 parts of a colorant, and 0.04 parts of a catalyst; The cross-linking agent is polymethylhydrogensiloxane (PMHS); The chain extender is hydroxyl-terminated polydimethylsiloxane; The monofunctional vinyl group is vinyl trimethoxysilane (VTMS); The inhibitor is ethynylcyclohexanol (ECH); The flame retardant is aluminum hydroxide (ATH); The catalyst is a platinum-divinyltetramethyldisiloxane complex; The colorant is red iron oxide, and the particle size of the colorant is 0.5-5 μm; The method for preparing the phase-change compressible silicone gasket based on additive manufacturing comprises the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir at 400 rpm for 40 minutes at 60° C. and vacuum degree -0.095 MPa to obtain a matrix premix system; S2, functional filler dispersion: flame retardants are added to the matrix premix system in sequence, and dispersed by a three-roll mill to obtain a dispersion system; colorants are added to the dispersion system, and an ultrasonic disperser is used to treat the dispersion system at 500W and 20kHz for 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 6 minutes; slowly dropwise add a crosslinking agent and stir for 18 minutes; finally add a catalyst and stir for 8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1MPa and 25°C for 30 minutes, and control the viscosity to 5500-5800mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.3mm. The moving speed and extrusion amount of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 15 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 2mm, and the printing speed is 20mm / s; S6. Post-processing: After printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket.

[0025] Comparative Example 2 This comparative example provides a silicone gasket, which includes, by mass, 42 parts of methyl vinyl silicone rubber, 1.4 parts of a cross-linking agent, 0 parts of a chain extender, 18 parts of a monofunctional vinyl, 0.08 parts of an inhibitor, 32 parts of a flame retardant, 4 parts of a phase change microcapsule, 2 parts of a colorant, and 0.04 parts of a catalyst; The cross-linking agent is polymethylhydrogensiloxane (PMHS); The monofunctional vinyl group is vinyl trimethoxysilane (VTMS); The inhibitor is ethynylcyclohexanol (ECH); The flame retardant is aluminum hydroxide (ATH); The catalyst is a platinum-divinyltetramethyldisiloxane complex; The phase change microcapsule is a paraffin core-shell microcapsule, which is composed of a core and an outer shell, wherein the core is paraffin, the outer shell is silicon dioxide, and the phase change microcapsule is a paraffin@SiO2 phase change microcapsule; The colorant is red iron oxide, and the particle size of the colorant is 0.5-5 μm; The method for preparing the phase-change compressible silicone gasket based on additive manufacturing comprises the following steps: S1. Matrix premix: Add methyl vinyl silicone rubber and monofunctional vinyl into a mixer and stir at 60°C and vacuum degree -0.095 MPa for 40 minutes at a stirring speed of 400 rpm to obtain a matrix premix system; S2, functional filler dispersion: flame retardant and phase change microcapsule are added to the matrix premix system in sequence, and dispersed by a three-roll mill to obtain a dispersed system; colorant is added to the dispersed system, and an ultrasonic disperser is used to treat at 500W, 20kHz for 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 6 minutes; slowly dropwise add a crosslinking agent and stir for 18 minutes; finally add a catalyst and stir for 8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1MPa and 25°C for 30 minutes, and control the viscosity to 5500-5800mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.3mm. The moving speed and extrusion amount of the nozzle are precisely controlled to ensure the accuracy and thickness of each layer. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 15 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 2mm, and the printing speed is 20mm / s; S6. Post-processing: After printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket.

[0026] Comparative Example 3 This comparative example provides a silicone gasket. The composition of this comparative example is the same as that of the silicone gasket in Example 1. This comparative example adopts a traditional molding method.

[0027] The performance of the phase-change compressible silicone gaskets prepared in the above-mentioned Examples 1 to 3 and the silicone gaskets prepared in Comparative Examples 1 to 3 was tested, and the test results are shown in Table 1.

[0028] Table 1

[0029] As can be seen from Table 1, Example 1 and Comparative Example 1 show that adding 4 parts of microcapsules increases the hotspot delay time from 5 min to 18 min, and the phase change enthalpy reaches 23 J / g; Example 1 and Comparative Example 2 show that not adding a chain extender causes the permanent deformation to increase to 15%, and the interlayer bonding force is poor; Example 1 and Comparative Example 3 show that the dimensional accuracy of additive manufacturing is higher, but the surface finish is slightly inferior; and additive manufacturing saves mold costs; In Example 2, when the amount of microcapsules added is 5 parts, the phase change enthalpy is optimal (25 J / g), but the cost is slightly higher.

[0030] In summary, the phase change material designed by adding a special formula in the present invention can dynamically change size with temperature changes, sensitively follow the size changes of components, have multiple functions such as thermal conductivity, and very good elasticity and thermal stability; thermoplastic elastomers can ensure initial thickness and elasticity under high and low temperature cycles; there is no oil leakage and very low small molecule volatilization; the additive manufacturing of the present invention can pre-generate visual virtual drawings, which is convenient for adjusting and optimizing parameters before production to meet customer needs. Once the traditional mold is opened, it cannot be modified and can also be transferred to other terminals for off-site production; the quality and appearance of the materials produced by the additive manufacturing of the present invention are controllable, and the phase change silicone compression gasket is produced by screw extrusion + spraying layer by layer printing, which can realize off-site production, no burrs, save materials, do not require additional cleaning, are environmentally friendly and simple, greatly save production costs, and can also be expanded to the production of other polymer materials; the present invention can achieve phase change compressibility, intelligent dynamic size change, and has a unique silicone gasket compression ratio curve.

[0031] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A phase-change compressible silicone gasket based on additive manufacturing, characterized in that: Calculated by mass, it includes 40-45 parts of methyl vinyl silicone rubber, 1.3-1.5 parts of cross-linking agent, 0.8-1.0 parts of chain extender, 15-20 parts of monofunctional vinyl, 0.05-0.1 parts of inhibitor, 30-35 parts of flame retardant, 3-5 parts of phase change microcapsules, 1-2 parts of colorant and 0.03-0.05 parts of catalyst.

2. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The crosslinking agent is selected from one or more of polymethylhydrogensiloxane, HMS-991, dicumyl peroxide, and 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane.

3. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The chain extender is selected from one or more of hydroxyl-terminated polydimethylsiloxane, α,ω-dihydroxy polydimethylsiloxane, tetramethyl divinyl disiloxane, vinyl silicone oil, γ-aminopropyl triethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, and γ-glycidyl ether oxypropyl trimethoxysilane.

4. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The monofunctional vinyl group is selected from one of vinyl trimethoxysilane, vinyl triethoxysilane, vinyl methyl dimethoxysilane, vinyl dimethyl methoxysilane and γ-methacryloxypropyl trimethoxysilane.

5. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The inhibitor is selected from one or more of ethynyl cyclohexanol, methyl butynol, dimethyl ethynyl methanol, vinyl cyclohexene oxide, diethyl maleate, and dibutyl tin dilaurate.

6. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The flame retardant is selected from one of aluminum hydroxide, magnesium hydroxide, nano silicon dioxide, layered double hydroxide and carbon nanotube.

7. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The catalyst is selected from one of platinum-divinyltetramethyldisiloxane complex and RhCl(PPh3)3.

8. The phase-change compressible silicone gasket based on additive manufacturing according to claim 1, characterized in that: The phase change microcapsule is a paraffin core-shell microcapsule, which consists of an inner core and an outer shell. The inner core is selected from one of n-octadecane, n-eicosane and paraffin, and the outer shell is selected from one of melamine-formaldehyde resin, silicon dioxide and polymethyl methacrylate.

9. A phase-change compressible silicone gasket based on additive manufacturing as claimed in claim 1, characterized in that: The colorant is selected from titanium dioxide, red iron oxide, and black iron oxide, and the particle size of the colorant is 0.5-5 μm.

10. A method for preparing a phase-changing compressible silicone gasket based on additive manufacturing according to any one of claims 1 to 9, characterized in that: The steps include: S1. Matrix premix: Add methyl vinyl silicone rubber, monofunctional vinyl and chain extender into a mixer and stir for 30 to 45 minutes at 55 to 65°C and vacuum degree -0.095 MPa at a speed of 300 to 500 rpm to obtain a matrix premix system; S2. Functional filler dispersion: flame retardant and phase change microcapsules are sequentially added to the matrix premix system, and a three-roll mill is used to disperse the system to obtain a dispersion system; a colorant is added to the dispersion system, and an ultrasonic disperser is used to process the system at 500 W and 20 kHz for 15 to 18 minutes to obtain a mixture; S3, slurry preparation: cool the mixture to below 40°C; add an inhibitor thereto and stir for 5-8 minutes; slowly dropwise add a crosslinking agent and stir for 15-20 minutes; finally add a catalyst and stir for 5-8 minutes to obtain a final slurry, transfer the slurry to a vacuum planetary mixer, degas at -0.1 MPa and 25°C for 30 minutes, and control the viscosity to 5000-8000 mPa·s; S4, material extrusion: the slurry is fed into the screw extrusion nozzle of the printer. After the slurry is completely liquid in the nozzle, the nozzle moves to extrude the liquid slurry. The nozzle diameter is 0.1~0.4mm. S5, deposition molding: the extruded material is rapidly cooled and solidified in mid-air, and then deposited on the workbench. After each layer of deposition is completed, the workbench will rise 1~50 microns to deposit the next layer on a new plane. This process is repeated until the entire 3D model is completed; the printing layer thickness is 0.02mm~20mm, and the printing speed is 5mm / s~100mm / s; S6. Post-processing: After printing is completed, the model is post-processed, including removing the support structure, coating the surface, and coloring to obtain a phase-change compressible silicone gasket.

Images