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CN-121975085-A - 3D printable bi-component liquid polyurea material system and preparation and application thereof

CN121975085ACN 121975085 ACN121975085 ACN 121975085ACN-121975085-A

Abstract

The invention relates to a 3D printable bi-component liquid polyurea material system, and preparation and application thereof. The component A is polyisocyanate prepolymer with free-NCO content of 8% -18%, and the component B is mixture of amine terminated polyether and amine chain extender. The two components are mixed by a spiral mixing tube of a direct-writing type 3D printer, and an addition polymerization reaction rapidly occurs in the extrusion process, so that the instant gel and shaping are realized. By regulating and controlling the synthesis parameters of the prepolymer, the types and the proportion of the chain extender and adding functional auxiliaries such as thixotropic agents and the like into the component B, the material has proper rheological property and reactivity, the initial setting time can be controlled to be 30-120 seconds, and the extrusion smoothness and the structural shape fidelity in the printing process are effectively balanced. The polyurea elastomer prepared by the method can be precisely molded into complex porous and gradient structures, has excellent mechanical properties, high rebound rate (more than or equal to 95%) and dimensional stability, and provides new materials and new ways for manufacturing customized elastic devices.

Inventors

  • TANG CHEN
  • WANG JINLIN
  • TANG YUFEI
  • LIU ZHAOWEI

Assignees

  • 西安理工大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (8)

  1. 1. The 3D printable bi-component liquid polyurea material system comprises a component A and a component B, and is characterized in that the component A is a polyisocyanate prepolymer, and is prepared by reacting polyisocyanate with polyether polyol or polyester polyol, and the free-NCO content is 8% -18%; the component B consists of amine-terminated polyether and amine chain extender, wherein the amine-terminated polyether accounts for 60-90% and the amine chain extender accounts for 10-40% in percentage by mass; the volume mixing ratio of the component A to the component B is 1:1-1:2.
  2. 2. The two-component liquid polyurea material system of claim 1, wherein the polyisocyanate in the a-component is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate.
  3. 3. The two-component liquid polyurea material system according to claim 1, wherein the polyether polyol is polyoxypropylene glycol, polyoxyethylene glycol or polytetrahydrofuran glycol, the molecular weight of the polyether polyol is 500-3000, the polyester polyol is one of adipic acid polyester glycol and polycaprolactone glycol, and the molecular weight of the polyether polyol is 500-2500.
  4. 4. The two-component liquid polyurea material system according to claim 1, wherein the amine-terminated polyether in the component B is a polyoxypropylene diamine, a polyoxyethylene diamine or a polytetrahydrofuran diamine, and has a molecular weight of 400-2000; the amine chain extender is selected from one or more of diethyl toluene diamine, dimethyl thio toluene diamine and N, N' -dialkyl methyl diamine.
  5. 5. The two-component liquid polyurea material system according to claim 1, wherein the component B further comprises one or more auxiliary agents of thixotropic agent accounting for 0.1% -5% of the total mass of the component B, leveling agent accounting for 0.1% -2% of the total mass of the component B, and pigment or filler accounting for 0.5% -5% of the total mass of the component B.
  6. 6. The two-component liquid polyurea material system according to claim 5, wherein the thixotropic agent is fumed silica, and the leveling agent is one or more of polyether modified siloxane, fluorocarbon modified polysiloxane and acrylate leveling agents.
  7. 7. The method of preparing a two-component liquid polyurea material system as claimed in any one of claims 1 to 6, comprising the steps of: s1, preparing a component A, namely mixing polyisocyanate and polyether polyol or polyester polyol according to the proportion of an isocyanate index R value of 1.05-1.20, and reacting for 2-4 hours under the protection of nitrogen at 70-85 ℃ to obtain a polyisocyanate prepolymer with free-NCO content of 8% -18%; s2, preparing a component B, namely mixing amine-terminated polyether and an amine chain extender according to a preset mass ratio, optionally adding an auxiliary agent, and uniformly stirring and mixing at 40-60 ℃; S3, printing pretreatment, namely respectively filling the component A and the component B into a charging barrel of a double-component 3D printer, and carrying out vacuum defoamation for 30-120 minutes at 20-35 ℃; and S4, printing and curing, namely pumping A, B components into a spiral mixing tube through a direct-writing type 3D printer, extruding and printing by a needle head to form, and curing the printing part for 12-24 hours at room temperature to obtain the polyurea elastomer part.
  8. 8. Use of the polyurea elastomer component obtained by the preparation method according to claim 7 in the manufacture of customized elastic devices in the fields of aerospace, biomedical and software robotics.

Description

3D printable bi-component liquid polyurea material system and preparation and application thereof Technical Field The invention relates to the technical field of intersection of high polymer materials and additive manufacturing, in particular to a double-component liquid polyurea material system suitable for direct-writing type 3D printing, and also relates to preparation and application of the material system. Background Polyurea materials are widely used in the fields of coating, sealing, protection and the like due to the characteristics of excellent mechanical properties, wear resistance, chemical corrosion resistance, high elasticity and the like. However, conventional polyurea materials are typically formed using spray or casting processes, which are difficult to meet for precision part manufacturing requirements with complex geometries. With the development of additive manufacturing technology, direct-write 3D printing is receiving widespread attention with free-forming of its high-resolution, complex structures. However, the elastomer systems currently suitable for direct-write 3D printing are still relatively limited, and especially polyurea systems with fast curing properties, good shape retention and excellent final properties have not been reported. In the prior art, the elastomer materials such as polyurethane, silicone rubber and the like which can be used for 3D printing often have the problems of low curing speed, low molding precision, poor adhesive force, insufficient mechanical property and the like. Therefore, a double-component polyurea material system which is suitable for direct-writing 3D printing, has the advantages of rapid solidification, high-precision molding and excellent comprehensive performance is developed, and has important significance for promoting the manufacture of complex structural members of an elastomer. Disclosure of Invention Aiming at the problem that the existing polyurea raw material cannot be directly printed, the invention provides a 3D-printable bi-component liquid polyurea material system and a preparation and use method thereof. The system can realize rapid in-situ gel in the printing process, good shaping after extrusion and excellent mechanical property and dimensional stability after complete solidification through component design and process optimization. In one aspect, the present invention provides a 3D printable two-component liquid polyurea material system comprising a component a and a component B: the component A is a polyisocyanate prepolymer, and is prepared by reacting polyisocyanate with polyether polyol or polyester polyol to generate a prepolymer with an isocyanate group (-NCO) end group, wherein the free-NCO content is 8% -18%, and the reaction formula is as follows: nOCN-R-NCO + nHO-R'-OH → [-CONH-R-NHCOO-R'-]n (wherein R is a hydrocarbon segment of a polyisocyanate and R' is a hydrocarbon segment of a polyol); The component B is a mixed system of amine-terminated polyether and amine chain extender, wherein the amine-terminated polyether accounts for 60-90% and the amine chain extender accounts for 10-40% in percentage by mass; in the 3D printing process, the-NCO group in the component A and the-NH 2 group in the component B undergo rapid addition polymerization reaction in a spiral mixing tube, and are immediately solidified after being extruded by a needle head to form the polyurea elastomer with a regular pore structure, wherein the reaction formula is as follows: nOCN-R-NCO+nH 2N-R''-NH2 → nOCN-R-NHCONH-R''-NH2 (wherein R '' is a hydrocarbyl segment of an amine terminated polyether); the volume mixing ratio of the component A to the component B is 1:1-1:2. In one embodiment, the polyisocyanate is selected from one or more of diphenylmethane diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and isophorone diisocyanate. The polyether polyol is polyoxypropylene glycol, polyoxyethylene glycol or polytetrahydrofuran glycol, the molecular weight of the polyether polyol is 500-3000, the polyester polyol is one of adipic acid polyester glycol and polycaprolactone glycol, and the molecular weight of the polyester polyol is 500-2500. The amine-terminated polyether is polyoxypropylene diamine, polyoxyethylene diamine or polytetrahydrofuran diamine, and the molecular weight is 400-2000. The amine chain extender is selected from one or more of diethyl toluene diamine, dimethyl thio toluene diamine and N, N' -dialkyl methyl diamine. Preferably, in order to further adjust the printing performance, one or more of 0.1% -5% of thixotropic agent, 0.1% -2% of flatting agent and 0.5% -5% of pigment or filler can be added into the component B according to mass percent. In one embodiment, the thixotropic agent is fumed silica, and the addition of the thixotropic agent can enable the extruded wire to quickly recover strength after leaving the needle, so that the large-span pore structure is effectively supported, and the shape fidelity is impr