Preparation method of 3D printing polyurea elastomer lattice

Abstract

In order to solve the problem that a polyurea elastomer forming process is single, a reaction process is controlled through a prepolymer method, multiple hydrogen bonds are introduced by utilizing dihydrazide chain extension, a boron-oxygen dynamic bond is introduced to strengthen dissipation capacity, a polyurea molecular structure capable of being subjected to heat processing repeatedly is obtained, and a preparation method of a 3D printing polyurea elastomer lattice is developed. The raw materials are cheap and easy to obtain, and the preparation process is simple and efficient and suitable for batch production.

Description

Technical Field

[0001] The invention belongs to the field of thermoplastic (polyurea) elastomers, and specifically relates to a method for preparing a 3D printed polyurea elastomer lattice. Background Art

[0002] Additive Manufacturing technology has developed rapidly in recent years and has received widespread attention from academia and industry. It is also known as 3D printing. 3D printing can be used to produce high-precision and complex structural parts. By creating precisely designed complex 3D geometries, performance can be improved or new functions can be realized. Polyurea elastomers are rich in urea bonds and have higher mechanical strength and impact resistance than polyurethane elastomers. In addition to the properties of the material itself, the preparation of mechanical metamaterials through lattice structure molding can achieve excellent energy dissipation. At present, due to the limitations of the synthesis method and reaction characteristics of polyurea, spraying is its common molding process. It is still a challenge to use polyurea elastomers to prepare 3D printed lattices and other products with fine microstructures. Summary of the invention

[0003] The purpose of the present invention is to develop a 3D printed polyurea elastomer lattice, which uses a prepolymer method to control the polyurea sequence structure, uses solvent dilution to control the reaction process, and introduces multiple hydrogen bonds to obtain a polyurea molecular structure that can be repeatedly heat-processed, uses melt extrusion to prepare 3D printed polyurea elastomer filaments, and uses an FDM printer to prepare polyurea elastomer lattices. The preparation process is simple, the reaction conditions are mild, and batch preparation is easy to achieve.

[0004] In order to achieve the above purpose, the technical solution is as follows:

[0005] Step (1): after long-chain diamine and short-chain diisocyanate are diluted evenly with a small amount of solvent, the diamine monomer dilution liquid is gradually added dropwise into the diisocyanate dilution liquid to obtain a terminal isocyanate prepolymer A.

[0006] Step (2): weigh 100 parts of the terminal isocyanate prepolymer A, add 1 to 50 parts of a dihydrazide diluent, add 0.5 to 30 parts of a boron hydroxyl crosslinking agent diluent, add 0 to 5 parts of a catalyst, and obtain a milky white suspension, wherein the molar ratio of isocyanate to active hydrogen (including boron hydroxyl and amino groups) is 1: (0.95 to 1.05), heat and continuously stir until a clear solution is obtained, and evenly pour the solution into a polytetrafluoroethylene mold, place the solution in a vacuum oven to dry and remove the solvent, and solidify the solution to obtain a polyurea elastomer.

[0007] Step (3): cutting the polyurea elastomer into pieces, and using a desktop twin-screw extruder to melt extrude the pieces to obtain a 3D printing polyurea elastomer filament with a diameter of 1.75 mm, wherein the melt extrusion temperature is set at 160 to 220 degrees Celsius;

[0008] Step (4): Place the 3D polyurea elastomer filament into an FDM printer and prepare the polyurea elastomer lattice by extrusion deposition.

[0009] The long-chain diamine described in step (1) is any one of polyetheramine D1000 and polyetheramine D2000.

[0010] The diisocyanate described in step (1) is any one of isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

[0011] The dihydrazide described in step (2) is any one of adipic acid dihydrazide (ADH) and isophthalic acid dihydrazide (IPDH).

[0012] The boron-containing hydroxyl crosslinking agent described in step (2) is any one or a combination of boric acid, 1,4-phenylenediboronic acid, 3-aminophenylboronic acid, and 4-aminophenylboronic acid. The catalyst described in step (2) is any one of triethylamine (TEA), bicycloguanidine (TBD), and dibutyltin dilaurate (DBTDL). The curing temperature described in step (2) is room temperature or 60 degrees Celsius, and the curing time is 8 to 24 hours.

[0013] In view of the problem of single polyurea elastomer molding process, the present invention controls the reaction process through a prepolymer method, introduces multiple hydrogen bonds by dihydrazide chain extension, and introduces boron-oxygen dynamic bonds to enhance the dissipation capacity, thereby developing a 3D printed polyurea elastomer lattice.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. The molecular sequence structure is controllable, the preparation process is simple, and it is suitable for industrial mass production.

[0016] 2. Through 3D printing, the preparation of polyurea elastomer lattice is realized, taking into account both light weight and excellent mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 .3D printing polyurea elastomer filament photo

[0018] Figure 2 .3D printed polyurea elastomer lattice photo

[0019] Figure 3 .3D printed lattice cyclic compression recovery curve DETAILED DESCRIPTION

[0020] In order to further explain the technical solution of the present invention, the following is a specific description in conjunction with the embodiments, but the protection scope of the present invention is not limited to these embodiments, and non-essential improvements and adjustments made to the present invention by those skilled in the art all fall within the protection scope of the present invention.

[0021] Example 1

[0022] 2.2 parts of HMDI and 7.6 parts of polyetheramine D2000 were weighed by weight, and reacted at room temperature and pressure for 3 hours under nitrogen protection. Then 0.2 parts of boric acid were weighed and dispersed in the solvent, and added to the reaction system at 60 degrees Celsius. After maintaining the reaction at 60 degrees Celsius for 20 hours, a uniform and stable transparent colorless solution was obtained. After stirring evenly, it was poured into a polytetrafluoroethylene mold, placed in a vacuum oven to remove the solvent and solidify to obtain a polyurea elastomer 1; further, a desktop twin-screw extruder was used to melt extrude to obtain a 3D printed polyurea elastomer filament with a diameter of 1.75 mm, and the melt extrusion temperature was set to 160-220 degrees Celsius. The 3D polyurea elastomer filament was placed in an FDM printer, and extrusion deposition was performed to prepare a polyurea elastomer lattice. The extrusion deposition process was set as follows: melt temperature 240°C, hot plate temperature 35°C, layer height 0.2mm, drape speed 30mm / s, sparse filling density 15% and filling direction 45°.

[0023] Example 2

[0024] Weigh 2.7 parts of HMDI and 6.6 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.10 parts of boric acid and 0.6 parts of ADH dispersed in the solvent and added to the reaction system at 60 degrees Celsius, and maintained at 60 degrees Celsius for 20 hours to obtain a uniform and stable transparent colorless solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it, polyurea elastomer 3; further use a desktop twin-screw extruder to melt extrude to obtain a 3D printing polyurea elastomer filament with a diameter of 1.75 mm, the melt extrusion temperature is set to 160-220 degrees Celsius, put the 3D polyurea elastomer filament into the FDM printer, and extrude and deposit to prepare a polyurea elastomer lattice. The extrusion deposition process settings were: melt temperature 240°C, hot plate temperature 35°C, layer height 0.2 mm, draping speed 30 mm / s, sparse packing density 15% and filling direction 45°.

[0025] Example 3

[0026] Weigh 2.6 parts of HMDI and 6.28 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 0.02 parts of boric acid and 1.1 parts of IPDH, disperse them in a solvent, add them to the reaction system at 60 degrees Celsius, and maintain the reaction at 60 degrees Celsius for 20 hours to obtain a uniform, stable, transparent, colorless solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it to obtain a polyurea elastomer 5; further use a desktop twin-screw extruder to melt extrude to obtain a 3D printed polyurea elastomer filament with a diameter of 1.75 mm, the melt extrusion temperature is set to 160-220 degrees Celsius, put the 3D polyurea elastomer filament into an FDM printer, and extrude and deposit to prepare a polyurea elastomer lattice. The extrusion deposition process settings were: melt temperature 240°C, hot plate temperature 35°C, layer height 0.2 mm, draping speed 30 mm / s, sparse packing density 15% and filling direction 45°.

[0027] Comparative Example 1

[0028] Weigh 2.6 parts of HMDI and 6.3 parts of polyetheramine D2000 by weight, react at room temperature and pressure for 3 hours under nitrogen protection, then weigh 1.1 parts of ADH dispersed in the solvent and added to the reaction system at 60 degrees Celsius, and maintain 60 degrees Celsius for 20 hours to obtain a uniform and stable transparent colorless solution. After stirring evenly, pour it into a polytetrafluoroethylene mold, place it in a vacuum oven to remove the solvent and solidify it to obtain a polyurea elastomer comparative example 1; further use a desktop twin-screw extruder to melt extrude to obtain a 3D printed polyurea elastomer filament with a diameter of 1.75 mm, the melt extrusion temperature is set to 160-220 degrees Celsius, and the 3D polyurea elastomer filament is placed in an FDM printer, and extrusion deposition is used to prepare a polyurea elastomer lattice. The extrusion deposition process is set as follows: melt temperature 240°C, hot plate temperature 35°C, layer height 0.2mm, drape speed 30mm / s, sparse filling density 15% and filling direction 45°.

[0029] The above is only a typical optimized embodiment of the present invention, and is not any formal or substantial limitation of the present invention. Under the premise of not changing the method of the present invention, several improvements and supplements can be made, and these improvements and supplements should also be regarded as the protection scope of the present invention. For those skilled in the art, without departing from the scope of the present invention, the equivalent changes made by using the technical content disclosed above should be regarded as equivalent embodiments of the present invention and still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a 3D printed polyurea elastomer lattice, characterized in that The steps include: Step (1): after long-chain diamine and short-chain diisocyanate are diluted evenly with a small amount of solvent, the diamine monomer dilution liquid is gradually added dropwise into the diisocyanate dilution liquid to obtain a terminal isocyanate prepolymer A. Step (2): weigh 100 parts of the terminal isocyanate prepolymer A, add 1 to 50 parts of a dihydrazide diluent, add 0.5 to 30 parts of a boron hydroxyl crosslinking agent diluent, add 0 to 5 parts of a catalyst, and obtain a milky white suspension, wherein the molar ratio of isocyanate to active hydrogen (including boron hydroxyl and amino groups) is 1: (0.95 to 1.05), heat and continuously stir until a clear solution is obtained, and evenly pour the solution into a polytetrafluoroethylene mold, place the solution in a vacuum oven to dry and remove the solvent, and solidify the solution to obtain a polyurea elastomer. Step (3): cutting the polyurea elastomer into pieces, and using a desktop twin-screw extruder to melt extrude the pieces to obtain a 3D printing polyurea elastomer filament with a diameter of 1.75 mm, wherein the melt extrusion temperature is set at 160 to 220 degrees Celsius; Step (4): Place the 3D polyurea elastomer filament into an FDM printer and prepare the polyurea elastomer lattice by extrusion deposition.

2. A method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that Any one of the long-chain diamine polyetheramine D1000 and polyetheramine D2000.

3. The method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that The diisocyanate is any one of isophorone diisocyanate (IPDI), toluene diisocyanate (TDI) and 4,4'-dicyclohexylmethane diisocyanate (HMDI).

4. The method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that The dihydrazide is any one of adipic acid dihydrazide (ADH) and isophthalic acid dihydrazide (IPDH).

5. The method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that The boron-containing hydroxyl crosslinking agent is any one or a combination of boric acid, 1,4-phenylenediboric acid, 3-aminophenylboric acid, and 4-aminophenylboric acid.

6. A method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that The catalyst is any one of triethylamine (TEA), bicyclic guanidine (TBD) and dibutyltin dilaurate (DBTDL).

7. The method for preparing a 3D printed polyurea elastomer lattice according to claim 1, characterized in that The curing temperature is room temperature or 60 degrees Celsius, and the curing time is 8 to 24 hours.

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