Preparation method of ultraviolet curing organic silicon flame-retardant thermal insulation material for 3D printing

Abstract

The invention provides a preparation method of an ultraviolet curing organic silicon flame-retardant thermal insulation material for 3D printing. The preparation method comprises the following steps: step 1, preparing alicyclic epoxy polysiloxane; step 2, mixing 70 to 80 parts of the epoxy polysiloxane of the alicyclic group, 5 to 15 parts of vinyl-terminated polysiloxane, 5 to 15 parts of a nano reinforcing filler, 5 to 15 parts of organic silicon resin, 5 to 6 parts of a silane coupling agent, 0.1 to 0.5 part of a photoinitiator, 0.5 to 3 parts of a stabilizer, 0.1 to 0.5 part of a flame retardant and 0.01 to 0.06 part of a terminating agent, and carrying out vacuum defoaming, so as to obtain a finished product. The ultraviolet curing organic silicon flame-retardant thermal insulation material for 3D printing is obtained. The material prepared by the method provided by the invention is a thixotropic mixture, does not need to be heated and melted during printing, has very good fluidity, also has very good formability after printing, is high in ultraviolet curing speed, simple and feasible to operate, difficult to shrink and warp, high in mechanical strength and good in toughness, and is very suitable for 3D printing.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to a method for preparing a UV-curable organic silicon flame-retardant heat-insulating material for 3D printing. Background Art

[0002] 3D printing technology is a technology that uses computers to build three-dimensional models of objects and directly shapes them. It is the intersection of multiple disciplines such as bioengineering, material molding, automatic control, and computer modeling. Compared with traditional molding technology, it does not require traditional multiple processing procedures. It can automatically and accurately manufacture parts of any complex shape on a single device through program control. During the implementation of 3D printing, high-temperature heating is not required, which reduces energy consumption, special solvents are not required, environmental pollution is reduced, UV curing is rapid, and production efficiency is greatly improved.

[0003] The UV curing materials used in 3D printing at home and abroad are based on the principle of free radical UV curing, in which acrylate or polymer materials with acrylate groups are used as prepolymers. The curing mechanism is to convert double bonds into single bonds through addition reaction. This type of photosensitive resin has the advantages of fast curing, low viscosity, good toughness, and low cost. However, the shrinkage rate of molded parts is large during curing, the molded parts are prone to warping, the stress deformation is large, the curing rate is low, and secondary curing is required. There are also cationic UV curing principles at home and abroad, in which epoxy resin modified polymer materials are used as prepolymers. The curing mechanism is through cationic polymerization reaction. The advantages of cationic resins are small volume shrinkage during polymerization, high reaction curing rate, and no secondary curing treatment is required after molding. However, they have the disadvantages of high viscosity and difficult processing. The method of reducing viscosity by adding low-viscosity prepolymers will result in the disadvantages of low mechanical strength of the material and easy precipitation of small molecules. Summary of the invention

[0004] In order to solve the problems existing in the prior art, the present application proposes a method for preparing a UV-curable silicone flame-retardant thermal insulation material for 3D printing.

[0005] In order to achieve the above-mentioned purpose, the present application proposes a method for preparing a UV-curable silicone flame-retardant thermal insulation material for 3D printing, comprising the following steps:

[0006] Step 1, preparing alicyclic epoxy polysiloxane;

[0007] Step 2: 70-80 parts of alicyclic epoxylated polysiloxane, 5-15 parts of terminal vinyl polysiloxane, 5-15 parts of nano-reinforced filler, 5-15 parts of silicone resin, 5-6 parts of silane coupling agent, 0.1-0.5 parts of photoinitiator, 0.5-3 parts of stabilizer, 0.1-0.5 parts of flame retardant, and 0.01-0.06 parts of terminator are mixed and degassed under reduced pressure to obtain a UV-curable silicone flame-retardant and thermal insulation material for 3D printing.

[0008] In some embodiments, in step 1, the preparation process of the alicyclic epoxylated polysiloxane is as follows:

[0009] Step 101, adding 0.01-0.5 parts of the catalyst to silicone oil with a viscosity of 20-50CS to dilute it, and adding 0.5-3 parts of the stabilizer to the silicone oil, during which the temperature is controlled at 40-60°C;

[0010] Step 102, uniformly mixing 30-50 parts of epoxidized cycloolefin organic matter with olefin groups and 20-50 parts of hydrogenated polymethylsiloxane;

[0011] Step 103, under a protective gas environment, add the liquid prepared in step 101 dropwise into the mixture prepared in step 102, or add the mixture prepared in step 102 into the liquid prepared in step 101, then control the temperature at 40-80°C, react for 3h-6h, cool down, and vacuum degas to obtain alicyclic epoxy polysiloxane.

[0012] In some embodiments, the cycloolefin organic compound with an olefin group includes one or more of vinyl cyclopentene epoxide, vinyl cyclohexene epoxide, propenyl cyclopentene epoxide, and propenyl cyclohexene epoxide; the hydrogen content of the hydrogenated polymethylsiloxane is between 0.1% and 0.3%; the catalyst is one or more of a palladium catalyst, a rhodium catalyst, a platinum catalyst, and a ruthenium catalyst.

[0013] In some embodiments, the vinyl-terminated polysiloxane has a viscosity of 3000 CS-8000 CS.

[0014] In some embodiments, the nano-reinforced filler is one or more of nano-silica, silicon powder, glass beads, and quartz powder; the nano-silica is one or more of fumed silica, precipitated silica, modified fumed silica, and modified precipitated silica.

[0015] In some embodiments, the organic silicone resin is one or both of methyl silicone resin and methylphenyl silicone resin; the silane coupling agent is one or more of KH560, KH561, and KH570.

[0016] In some embodiments, the photoinitiator is one or more of a diazonium salt, a diaryl iodonium salt, a triaryl sulfonium salt, an alkyl sulfonium salt, an iron aromatic group, a sulfonyloxy ketone, and a triaryl siloxane ether.

[0017] In some embodiments, the stabilizer includes one or more of UV-P, UV-531, UV-326, UV-327, UV-1577, and UV-770.

[0018] In some embodiments, the terminator includes one or more of quinone, nitro, nitroso, hydroquinone, p-tert-butylcatechol, and wood tar.

[0019] In some embodiments, the flame retardant includes one or more of a bromine flame retardant, a boron flame retardant, a phosphine nitrogen flame retardant, a silicon flame retardant, and aluminum hydroxide.

[0020] The beneficial effect of the scheme of the present application lies in that the preparation method of the above-mentioned UV-curing silicone flame-retardant thermal insulation material for 3D printing can solve the problems existing in the above-mentioned prior art, and can also solve the problems that the current 3D printing materials have strict printing conditions, the printed parts have low strength, poor toughness, and it is difficult to clearly print and form tiny structures; the raw materials of the UV-curing silicone flame-retardant thermal insulation material involved in the present application are simple to prepare, and the material prepared by the method involved in the present application is a thixotropic mixture, which does not need to be heated and melted during printing. The material has good fluidity and good formability after printing, the UV curing speed is fast, the operation is simple and feasible, the material is not easy to shrink and warp, has high mechanical strength and good toughness, and is very suitable for 3D printing. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart of a method for preparing a UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing in an embodiment is shown. DETAILED DESCRIPTION

[0022] The specific implementation of the present application is further described below in conjunction with the accompanying drawings.

[0023] like Figure 1 As shown, the preparation method of the ultraviolet light-cured silicone flame-retardant and heat-insulating material for 3D printing involved in the present application comprises the following steps:

[0024] Step 1: preparing alicyclic epoxylated polysiloxane.

[0025] Step 2: 70-80 parts of alicyclic epoxylated polysiloxane, 5-15 parts of terminal vinyl polysiloxane, 5-15 parts of nano-reinforced filler, 5-15 parts of silicone resin, 5-6 parts of silane coupling agent, 0.1-0.5 parts of photoinitiator, 0.5-3 parts of stabilizer, 0.1-0.5 parts of flame retardant, 0.01-0.06 parts of terminator (the above components are calculated by weight), after mixing (for example, after mixing on a three-roll mill at room temperature of 4-30°C), decompression and degassing are performed to obtain a UV-curable silicone flame retardant and thermal insulation material for 3D printing.

[0026] Specifically, in step 1, the preparation process of the alicyclic epoxylated polysiloxane is as follows:

[0027] Step 101: Add 0.01-0.5 parts of catalyst to silicone oil with a viscosity of 20-50CS by weight for dilution, and add 0.5-3 parts of stabilizer to the silicone oil. During this period, the temperature is controlled at 40-60°C.

[0028] Step 102: uniformly mix 30-50 parts of epoxidized cycloolefin organic matter with olefin groups and 20-50 parts of hydrogenated polymethylsiloxane.

[0029] Step 103, under a protective gas environment, for example, using high-purity N2 as a protective gas, the liquid prepared in step 101 is added dropwise to the mixture prepared in step 102, or the mixture prepared in step 102 is added to the liquid prepared in step 101, and then the temperature is controlled at 40-80°C, the reaction is carried out for 3h-6h, and after cooling, vacuum degassing is performed to obtain alicyclic epoxy polysiloxane.

[0030] In this embodiment, the cycloolefin organic compound with olefin groups includes one or more of vinyl cyclopentene epoxide, vinyl cyclohexene epoxide, propenyl cyclopentene epoxide, and propenyl cyclohexene epoxide. The hydrogen content of the hydrogenated polymethylsiloxane is between 0.1% and 0.3% (accounting for the mass ratio of the organic compound itself), preferably 0.18% to 0.25%. The viscosity of the terminal vinyl polysiloxane is 3000CS to 8000CS, preferably 4000CS to 6000CS. The catalyst is one or more of palladium catalysts, rhodium catalysts, platinum catalysts, and ruthenium catalysts, preferably one or two of palladium catalysts and platinum catalysts.

[0031] The nano-reinforced filler is one or more of nano-silicon dioxide, silicon powder, glass beads, and quartz powder. The nano-silicon dioxide is one or more of fumed silica, precipitated silica, modified fumed silica, and modified precipitated silica. Preferably, fumed silica and modified fumed silica are one or two. The silicone resin is one or two of methyl silicone resin or methylphenyl silicone resin. The silane coupling agent is one or more of KH560, KH561, and KH570. The photoinitiator is one or more of diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron aromatic hydrocarbon group, sulfonyloxy ketone, and triaryl siloxane ether. Preferably, one or more of triaryl sulfonium salt, alkyl sulfonium salt, and iron aromatic hydrocarbon group are one or more. The stabilizer includes one or more of UV-P, UV-531, UV-326, UV-327, UV-1577, and UV-770. Preferably, one or more of UV-326, UV-327, and UV-1577 are used. The terminator includes one or more of quinone, nitro, nitroso, hydroquinone, p-tert-butylcatechol, and wood tar. Preferably, one or two of nitroso and hydroquinone are used. The flame retardant includes one or more of bromine flame retardant, boron flame retardant, phosphine nitrogen flame retardant (ADP, TDPP, etc.), silicon flame retardant (phenyl cage siloxane), and aluminum hydroxide.

[0032] The UV-curable silicone flame-retardant and heat-insulating material for 3D printing prepared by the method involved in the present application is directly loaded into the material box of the 3D printer, and is printed and cured under ultraviolet light until the printed sample is completely cured. The UV-curable silicone flame-retardant and heat-insulating material for 3D printing prepared by the method involved in the present application is printed and cured under ultraviolet light at room temperature, with fast curing speed, high efficiency, low pollution, simple and feasible processing technology, high degree of curing of the finished product after printing, not easy to produce lateral force shrinkage, high impact strength, the material itself is flame retardant and heat-insulating, very suitable for 3D printing curing, and compared with the traditional vulcanization process, this material has better processing characteristics.

[0033] Example 1

[0034] Add 50g of hydrogenated silicone oil and 50g of toluene as solvent to a dry four-necked flask, add 0.5g of stabilizer at the same time, control the temperature to about 50℃, drip the catalyst chloroplatinic acid solution for 5d (20d=1mL), pass high-purity N2 to drive away the air in the bottle and protect the reactant, then drip 20g of vinyl epoxide cyclohexene from a separatory funnel, heat to 75℃, and react at this temperature for 5.5h. After the reaction is completed, vacuum remove low-boiling substances, solvents and unreacted substances, then take out the product obtained from the flask and weigh it, then add 5g of terminal vinyl polysiloxane, 10g of methyl vinyl silicone resin, 5.5g of KH560, 5g of quartz powder, 2g of gas-phase modified silica, 0.4g of phosphorus flame retardant ADP, 0.2g of initiator diaryliodonium salt, 0.5g of stabilizer UV-1577, and 0.01g of terminator sodium nitrite. The mixture is mixed evenly in a three-roll grinder and deaerated under reduced pressure to obtain a UV-curable silicone flame-retardant and heat-insulating material for 3D printing.

[0035] Example 2

[0036] In a dry four-necked flask, 40 g of hydrogenated silicone oil and 50 g of toluene as a solvent were added, and 0.5 g of a stabilizer was added at the same time. The temperature was controlled at about 30°C, and a catalyst chloroplatinic acid solution was added dropwise for 4 d (20 d = 1 mL). High-purity N2 was introduced to drive away the air in the bottle and protect the reactant. Then 50 g of vinyl epoxide cyclohexene was added dropwise from a separatory funnel, and the temperature was raised to 78°C. The reaction was carried out at this temperature for 5 h. After the reaction was completed, low-boiling substances, solvents and unreacted substances were removed in vacuo, and the product obtained from the flask was taken out and weighed. Then, 16 g of vinyl-terminated polysiloxane, 4 g of methyl vinyl silicone resin, 2 g of KH561, 6 g of quartz powder, 3 g of gas-phase modified silica, 0.4 g of inorganic flame retardant aluminum hydroxide, 0.2 g of initiator alkyl sulfonium salt, 0.5 g of stabilizer UV-326, and 0.01 g of terminator hydroquinone were added. The mixture is mixed evenly in a three-roll grinder and deaerated under reduced pressure to obtain a UV-curable silicone flame-retardant and heat-insulating material for 3D printing.

[0037] Example 3

[0038] Add 35g of hydrogenated silicone oil and 50g of toluene as solvent to a dry four-necked flask, add 0.5g of stabilizer at the same time, control the temperature to about 42°C, drip the catalyst chloroplatinic acid solution for 5d (20d=1mL), pass high-purity N2 to drive away the air in the bottle and protect the reactant, then drip 45g of vinyl epoxide cyclohexene from a separatory funnel, raise the temperature to 70°C, and react at this temperature for 6h. After the reaction is completed, vacuum remove low-boiling substances, solvents and unreacted substances, then take out the product obtained from the flask and weigh it, then add 10g of terminal vinyl polysiloxane, 8g of methyl silicone resin, 5.5g of KH570, 6g of silicon powder, 3g of precipitated modified silica, 0.4g of silicon-based flame retardant phenyl cage siloxane, 0.2g of initiator alkyl sulfonium salt, 0.5g of stabilizer UV-327, and 0.01g of terminator hydroquinone. The mixture is mixed evenly in a three-roll grinder and deaerated under reduced pressure to obtain a UV-curable silicone flame-retardant and heat-insulating material for 3D printing.

[0039] The UV-curable organic silicon flame-retardant and heat-insulating materials for 3D printing obtained in the above three embodiments were added to the ink cartridge of the 3D printer in order, and the required product volume V1 of the printing material was measured. The molded product was printed out. During the printing process, the flowability of the finished product was observed. At the same time, the surface drying curing time of the product was tested with a handheld curing instrument. After the product was cured for 24 hours, the volume V2 of the molded product was tested by the drainage method. (V 1- V2) / V 1* The volume shrinkage of the product is 100%. After drying, the Shore hardness of the product is tested with a Shore hardness tester, and the impact strength of the product is tested with a simply supported beam impact strength tester. The following experimental records are made:

[0040] Table 1 Experimental data record table

[0041]

[0042] By comparison, it can be seen that since Example 2 did not strictly prepare the UV-curing silicone flame retardant and thermal insulation material for 3D printing according to the method involved in this patent application, the performance of the prepared material is not ideal. Example 1 and Example 3 both prepared the UV-curing silicone flame retardant and thermal insulation material for 3D printing according to the method involved in this patent application. The performance of the obtained materials is relatively ideal. The finished product after printing has a high degree of curing, is not prone to lateral force shrinkage, has high impact strength, and has good flame retardant and thermal insulation properties.

[0043] The above is only a preferred specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent substitutions or changes according to the technical solution and concept of the present application within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A method for preparing a UV-curable silicone flame-retardant and heat-insulating material for 3D printing, characterized in that: The following steps are involved: Step 1, preparing alicyclic epoxy polysiloxane; Step 2: 70-80 parts of alicyclic epoxylated polysiloxane, 5-15 parts of terminal vinyl polysiloxane, 5-15 parts of nano-reinforced filler, 5-15 parts of silicone resin, 5-6 parts of silane coupling agent, 0.1-0.5 parts of photoinitiator, 0.5-3 parts of stabilizer, 0.1-0.5 parts of flame retardant, and 0.01-0.06 parts of terminator are mixed and degassed under reduced pressure to obtain a UV-curable silicone flame-retardant and thermal insulation material for 3D printing.

2. The method for preparing the UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: In the step 1, the preparation process of the alicyclic epoxylated polysiloxane is as follows: Step 101, adding 0.01-0.5 parts of the catalyst to silicone oil with a viscosity of 20-50CS to dilute it, and adding 0.5-3 parts of the stabilizer to the silicone oil, during which the temperature is controlled at 40-60°C; Step 102, uniformly mixing 30-50 parts of epoxidized cycloolefin organic matter with olefin groups and 20-50 parts of hydrogenated polymethylsiloxane; Step 103, under a protective gas environment, add the liquid prepared in step 101 dropwise into the mixture prepared in step 102, or add the mixture prepared in step 102 into the liquid prepared in step 101, then control the temperature at 40-80°C, react for 3h-6h, cool down, and vacuum degas to obtain alicyclic epoxy polysiloxane.

3. The method for preparing the UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing according to claim 2, characterized in that: The cycloolefin organic compound with olefin groups includes one or more of vinyl cyclopentene epoxide, vinyl cyclohexene epoxide, propenyl cyclopentene epoxide, and propenyl cyclohexene epoxide; the hydrogen content of the hydrogenated polymethylsiloxane is between 0.1% and 0.3%; the catalyst is one or more of palladium catalysts, rhodium catalysts, platinum catalysts, and ruthenium catalysts.

4. The method for preparing the UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The viscosity of the vinyl-terminated polysiloxane is between 3000CS and 8000CS.

5. The method for preparing the UV-curable organic silicon flame retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The nano-reinforced filler is one or more of nano-silicon dioxide, silicon powder, glass beads, and quartz powder; the nano-silicon dioxide is one or more of fumed silica, precipitated silica, modified fumed silica, and modified precipitated silica.

6. The method for preparing the UV-curable organic silicon flame retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The organic silicon resin is one or both of methyl silicone resin and methylphenyl silicone resin; the silane coupling agent is one or more of KH560, KH561 and KH570.

7. The method for preparing the UV-curable organic silicon flame retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The photoinitiator is one or more of diazonium salt, diaryl iodonium salt, triaryl sulfonium salt, alkyl sulfonium salt, iron aromatic hydrocarbon group, sulfonyloxy ketone and triaryl siloxane ether.

8. The method for preparing the UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The stabilizer includes one or more of UV-P, UV-531, UV-326, UV-327, UV-1577, and UV-770.

9. The method for preparing the UV-curable organic silicon flame retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The terminator includes one or more of quinone, nitro, nitroso, hydroquinone, p-tert-butylcatechol, and wood tar.

10. The method for preparing the UV-curable organic silicon flame-retardant and heat-insulating material for 3D printing according to claim 1, characterized in that: The flame retardant includes one or more of a bromine flame retardant, a boron flame retardant, a phosphine nitrogen flame retardant, a silicon flame retardant, and aluminum hydroxide.

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