Ultrahigh-toughness polyurea acrylate photosensitive resin and preparation method thereof

Abstract

The invention discloses ultrahigh-toughness polyurea acrylate photosensitive resin and a preparation method thereof. According to the method, firstly, an isocyanate-terminated prepolymer is obtained, then rigid and flexible supramolecular chain segments are introduced into the prepolymer and connected in a staggered mode, the mismatched supramolecular effect is initiated, and the tensile property and toughness are improved. Finally, polyurea and acrylate are combined, polyurea is used as a high-toughness material and can remarkably improve the impact resistance and flexibility of the resin, and acrylate is used as a photocuring monomer, can be rapidly cured through illumination and has short curing time and good photocuring efficiency. By combining the two components, the toughness of the resin can be improved, and better photocuring performance can be kept, so that the application range of the resin in the existing field is expanded, and a higher-quality material choice can be provided for the development of emerging technologies. The ultrahigh-toughness polyurea acrylate photosensitive resin and the effective preparation method thereof have important practical significance and wide market prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of 3D printing, and in particular to an ultra-high toughness polyurea acrylate photosensitive resin and a preparation method thereof. Background Art

[0002] In the field of modern materials science, photosensitive resin, as an important light-curing material, is widely used in many industries such as 3D printing, coatings, inks, and electronic packaging. Traditional photosensitive resin materials usually have high rigidity and poor toughness, and are prone to brittle cracking. For parts that need to withstand large impact forces and stresses, the performance of traditional resins cannot meet the requirements. Therefore, the development of photosensitive resins with higher toughness has become a research hotspot in the industry.

[0003] As a high-toughness material, polyurea can significantly improve the impact resistance and flexibility of resins. As a photocurable monomer, acrylate can be quickly cured by light, with a short curing time and good photocuring efficiency. Combining polyurea with acrylate can not only improve the toughness of the resin, but also maintain good photocuring performance. In elastomers, the rigid and flexible supramolecular segments are combined to induce mismatch supramolecular effects, giving the matrix material high tensile strength and toughness. Ultra-high-toughness polyurea acrylate photosensitive resin can not only expand its application range in existing fields, but also provide better material options for the development of emerging technologies. For example, in the field of biomedical 3D printing, it can be used to make more durable implants; in precision mold manufacturing, it can improve the service life and precision of the mold. Therefore, the research and preparation of an ultra-high-toughness polyurea acrylate photosensitive resin and its effective preparation method have important practical significance and broad market prospects. Summary of the invention

[0004] The purpose of the present invention is to provide an ultra-high toughness polyurea acrylate photosensitive resin and a preparation method thereof. The polyurea acrylate photosensitive resin combines polyurea with acrylate, introduces rigid and flexible supramolecular segments, and the combination of the two supramolecular segments induces mismatch supramolecular effects, which gives the polyurea acrylate ultra-high toughness without affecting the photocuring performance.

[0005] The present invention provides an ultra-high toughness polyurea acrylate photosensitive resin and a preparation method thereof, which specifically comprises:

[0006] Step 1: Place an excess of diphenylmethane diisocyanate (MDI) and an appropriate amount of 1,6-hexanediol, as well as a catalyst dibutyltin dilaurate (DBTDL) and a solvent N,N-dimethylformamide into a three-necked round-bottom flask with a mechanical stirrer, a thermometer and a reflux condenser at room temperature. In a nitrogen atmosphere, heat the mixture to 80°C and react for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer, the structural formula of which is shown in Formula I:

[0007]

[0008] Step 2: After cooling the reaction system in the first step to 40°C, add appropriate amounts of rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) or flexible chain extender hexamethylenediamine under nitrogen atmosphere, keep the temperature of the reaction system at 50°C, mix and stir for 4 hours, and discharge into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain isocyanate-terminated polyurea oligomers containing rigid segment structures and isocyanate-terminated polyurea oligomers containing flexible segment structures, whose structural formulas are shown in Formula 2 and Formula 3 respectively:

[0009]

[0010] Step 3: Add the isocyanate-terminated polyurea oligomer containing a rigid segment structure and the isocyanate-terminated polyurea oligomer containing a flexible segment structure obtained in the second step, an appropriate amount of ethylenediamine, a catalyst dibutyltin dilaurate (DBTDL) and a solvent N,N-dimethylformamide into a three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. Under a nitrogen atmosphere, heat the mixture to 80°C for 2 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced, and its structural formula is shown in Formula IV:

[0011]

[0012] Step 4: Add the isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure obtained above, excess 2-aminoethyl methacrylate and solvent N,N-dimethylformamide into a three-necked round-bottom flask with mechanical stirring, thermometer and reflux condenser. Under nitrogen atmosphere, heat the mixture to 60°C for 4 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain a polyurea acrylate photosensitive resin with interlaced rigid segment structure and flexible segment structure, whose structural formula is shown in Formula V:

[0013]

[0014] Preferably, in the step 1, the molar ratio of 1,6-hexanediol to diphenylmethane diisocyanate is 1:1.3 to 1:1.5.

[0015] Preferably, the mass fraction of dibutyltin dilaurate in step 1 is 1% to 3%.

[0016] Preferably, in the step 2, the molar ratio of 4,4-diaminodiphenyl sulfone or hexamethylenediamine to the isocyanate-terminated polyurethane prepolymer is 1:1.2 to 1:1.4.

[0017] Preferably, the mass fraction of dibutyltin dilaurate in step three is 1% to 3%.

[0018] Preferably, in step 4, the molar ratio of the isocyanate-terminated polyurea oligomer having an alternating rigid segment structure and a flexible segment structure to 2-aminoethyl methacrylate is 1:1.1 to 1:1.3.

[0019] Beneficial effects of the present invention:

[0020] The present invention provides an ultra-high toughness polyurea acrylate photosensitive resin and a preparation method thereof. The polyurea acrylate photosensitive resin combines polyurea with acrylate, which can not only improve the toughness of the resin, but also maintain good photocuring performance. In addition, the rigid and flexible supramolecular segments are staggered and connected to induce mismatch supramolecular effects, giving the matrix material high tensile properties and toughness. This expands its application range in the existing field and can also provide a better material selection for the development of emerging technologies. The ultra-high toughness polyurea acrylate photosensitive resin and its effective preparation method have important practical significance and broad market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The engineering stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 1 of the present invention;

[0022] Figure 2 The true stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 1 of the present invention;

[0023] Figure 3 The engineering stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 2 of the present invention;

[0024] Figure 4 The true stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 2 of the present invention;

[0025] Figure 5 The engineering stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 3 of the present invention;

[0026] Figure 6This is the true stress-strain curve of the polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0027] The present invention provides an ultra-high toughness polyurea acrylate photosensitive resin and a preparation method thereof, which specifically comprises:

[0028] Step 1: Place excess diphenylmethane diisocyanate (MDI) and an appropriate amount of 1,6-hexanediol, as well as catalyst dibutyltin dilaurate (DBTDL) and solvent N,N-dimethylformamide into a three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser at room temperature. Heat the mixture to 80°C in a nitrogen atmosphere for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer.

[0029] Step 2: After cooling the reaction system in the first step to 40°C, add appropriate amounts of rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) or flexible chain extender hexamethylenediamine under nitrogen atmosphere, keep the temperature of the reaction system at 50°C, mix and stir for 4 hours, and discharge the product into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain isocyanate-terminated polyurea oligomers containing rigid segment structures and isocyanate-terminated polyurea oligomers containing flexible segment structures.

[0030] Step 3: Add the isocyanate-terminated polyurea oligomer containing a rigid segment structure and the isocyanate-terminated polyurea oligomer containing a flexible segment structure obtained in the second step, an appropriate amount of ethylenediamine, a catalyst dibutyltin dilaurate (DBTDL) and a solvent N,N-dimethylformamide into a three-necked round-bottom flask with a mechanical stirrer, a thermometer and a reflux condenser. Under a nitrogen atmosphere, heat the mixture to 80°C for 2 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced.

[0031] Step 4: Add the above obtained isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure, excess 2-aminoethyl methacrylate and solvent N,N-dimethylformamide into a three-necked round-bottom flask with mechanical stirring, thermometer and reflux condenser. Under nitrogen atmosphere, heat the mixture to 60°C for 4 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain a polyurea acrylate photosensitive resin with interlaced rigid segment structure and flexible segment structure.

[0032] According to the present invention, the molar ratio of 1,6-hexanediol to diphenylmethane diisocyanate in step 1 is 1:1.3 to 1:1.5, and the mass fraction of dibutyltin dilaurate is 1% to 3%. The reaction process is as follows:

[0033]

[0034] According to the present invention, the molar ratio of the 4,4-diaminodiphenyl sulfone or hexamethylenediamine to the isocyanate-terminated polyurethane prepolymer in step 2 is 1:1.2 to 1:1.4. The reaction process is as follows:

[0035]

[0036]

[0037] According to the present invention, the mass fraction of dibutyltin dilaurate in step 3 is 1% to 3%. The reaction process is as follows:

[0038]

[0039] According to the present invention, the molar ratio of the isocyanate-terminated polyurea oligomer with staggered rigid segment structure and flexible segment structure and 2-aminoethyl methacrylate in step 4 is 1:1.1 to 1:1.3. The reaction process is as follows:

[0040]

[0041] The present invention is further described in detail below with reference to specific examples, and the raw materials involved in the examples are all commercially available.

[0042] Example 1

[0043] 1) At room temperature, diphenylmethane diisocyanate (MDI) (19.50 g) and 1,6-hexanediol (7.08 g), dibutyltin dilaurate (DBTDL) (0.54 g) and solvent N,N-dimethylformamide (115 mL) were placed in a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. N,N-dimethylformamide was used as a solvent and dibutyltin dilaurate was used as a catalyst. Under a nitrogen atmosphere, the mixture was heated to 80°C for reaction for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer.

[0044] 2) After cooling the reaction system in the first step to 40°C, a rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) (11.92 g) or a flexible chain extender hexamethylenediamine (5.56 g) was added under a nitrogen atmosphere, and the temperature of the reaction system was maintained at 50°C. After mixing and stirring for 4 hours, the mixture was discharged into n-hexane. The product was collected by filtration, and the collected product was repeatedly washed with n-hexane for 3-5 times and then dried to obtain an isocyanate-terminated polyurea oligomer containing a rigid segment structure and an isocyanate-terminated polyurea oligomer containing a flexible segment structure.

[0045] 3) Add the isocyanate-terminated polyurea oligomer (14.86 g) containing a rigid segment structure and the isocyanate-terminated polyurea oligomer (13.54 g) containing a flexible segment structure obtained in the second step, ethylenediamine (0.60 g), catalyst dibutyltin dilaurate (DBTDL) (0.58 g) and solvent N,N-dimethylformamide (119 mL) into a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. Under a nitrogen atmosphere, heat the mixture to 80°C for 2 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced.

[0046] 4) Add the above obtained isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure (23.64) and 2-aminoethyl methacrylate (1.14g) and solvent N,N-dimethylformamide (100mL) into a 250mL three-necked round-bottom flask with mechanical stirring, thermometer and reflux condenser. Under nitrogen atmosphere, heat the mixture to 60°C for 4h and discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain a polyurea acrylate photosensitive resin with interlaced rigid segment structure and flexible segment structure.

[0047] The toughness of the synthesized material is 1020MJm -3 , the fracture true stress is 2.05GPa, indicating that it has excellent toughness and good crack resistance. The above excellent performance is achieved through the molecular structure design of the material, and then giving full play to the mismatch supramolecular effect. The mismatch supramolecular effect refers to the combination of rigid and flexible supramolecular segments in the elastomer, which causes mismatched supramolecular interactions. This mismatched interaction gives the matrix material high tensile strength and toughness through reversible and synchronous association / dissociation energy consumption.

[0048] Example 2

[0049] 1) At room temperature, diphenylmethane diisocyanate (MDI) (21 g) and 1,6-hexanediol (7.08 g), dibutyltin dilaurate (DBTDL) (0.54 g) and solvent N,N-dimethylformamide (120 mL) were placed in a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. N,N-dimethylformamide was used as a solvent and dibutyltin dilaurate was used as a catalyst. Under a nitrogen atmosphere, the mixture was heated to 80°C for reaction for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer.

[0050] 2) After cooling the reaction system in the first step to 40°C, a rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) (13.12 g) or a flexible chain extender hexamethylenediamine (6.04 g) was added under a nitrogen atmosphere, and the temperature of the reaction system was maintained at 50°C. After mixing and stirring for 4 hours, the mixture was discharged into n-hexane. The product was collected by filtration, and the collected product was repeatedly washed with n-hexane for 3-5 times and then dried to obtain an isocyanate-terminated polyurea oligomer containing a rigid segment structure and an isocyanate-terminated polyurea oligomer containing a flexible segment structure.

[0051] 3) Add the isocyanate-terminated polyurea oligomer (14.86 g) containing a rigid segment structure and the isocyanate-terminated polyurea oligomer (13.54 g) containing a flexible segment structure obtained in the second step, ethylenediamine (0.60 g), catalyst dibutyltin dilaurate (DBTDL) (0.58 g) and solvent N,N-dimethylformamide (119 mL) into a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. Under a nitrogen atmosphere, heat the mixture to 80°C for 2 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced.

[0052] 4) Add the above obtained isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure (23.64) and 2-aminoethyl methacrylate (1.14g) and solvent N,N-dimethylformamide (100mL) into a 250mL three-necked round-bottom flask with mechanical stirring, thermometer and reflux condenser. Under nitrogen atmosphere, heat the mixture to 60°C for 4h and discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain a polyurea acrylate photosensitive resin with interlaced rigid segment structure and flexible segment structure.

[0053] The toughness of the synthesized material is 1027MJm -3The fracture true stress is 2.15GPa, indicating that it has excellent toughness and good crack resistance. The above excellent properties are also achieved through mismatch supramolecular effects.

[0054] Example 3

[0055] 1) At room temperature, diphenylmethane diisocyanate (MDI) (22.5 g) and 1,6-hexanediol (7.08 g), dibutyltin dilaurate (DBTDL) (0.54 g) and solvent N,N-dimethylformamide (125 mL) were placed in a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. N,N-dimethylformamide was used as a solvent and dibutyltin dilaurate was used as a catalyst. Under a nitrogen atmosphere, the mixture was heated to 80°C for reaction for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer.

[0056] 2) After cooling the first step reaction system to 40°C, add a rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) (13.92g) or a flexible chain extender hexamethylenediamine (6.52g) respectively under a nitrogen atmosphere, keep the temperature of the reaction system at 50°C, mix and stir for 4 hours, and discharge the product into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer containing a rigid segment structure and an isocyanate-terminated polyurea oligomer containing a flexible segment structure.

[0057] 3) Add the isocyanate-terminated polyurea oligomer (14.86 g) containing a rigid segment structure and the isocyanate-terminated polyurea oligomer (13.54 g) containing a flexible segment structure obtained in the second step, ethylenediamine (0.60 g), catalyst dibutyltin dilaurate (DBTDL) (0.58 g) and solvent N,N-dimethylformamide (119 mL) into a 250 mL three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser. Under a nitrogen atmosphere, heat the mixture to 80°C for 2 hours and then discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced.

[0058] 4) Add the above obtained isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure (23.64g) and 2-aminoethyl methacrylate (1.14g) and solvent N,N-dimethylformamide (100mL) into a 250mL three-necked round-bottom flask with mechanical stirring, thermometer and reflux condenser. Under nitrogen atmosphere, heat the mixture to 60°C for 4h and discharge it into n-hexane. Filter and collect the product, and wash the collected product repeatedly with n-hexane for 3-5 times and then dry it to obtain a polyurea acrylate photosensitive resin with interlaced rigid segment structure and flexible segment structure.

[0059] The toughness of the synthesized material is 1015MJm -3 The fracture true stress is 2.01GPa, indicating that it has excellent toughness and good crack resistance. The above excellent properties are also achieved through mismatch supramolecular effects.

Claims

1. A method for preparing an ultra-high toughness polyurea acrylate photosensitive resin, comprising: Step 1: at room temperature, put an excess of diphenylmethane diisocyanate (MDI) and an appropriate amount of 1,6-hexanediol, a catalyst dibutyltin dilaurate (DBTDL) and a solvent N,N-dimethylformamide into a three-necked round-bottom flask equipped with a mechanical stirrer, a thermometer and a reflux condenser; In a nitrogen atmosphere, the mixture was heated to 80°C for 2 hours to synthesize an isocyanate-terminated polyurethane prepolymer, the chemical structure of which is shown in Formula I. Step 2: After cooling the reaction system in the first step to 40°C, add appropriate amounts of rigid chain extender 4,4-diaminodiphenyl sulfone (DDS) or flexible chain extender hexamethylenediamine under nitrogen atmosphere, keep the temperature of the reaction system at 50°C, mix and stir for 4 hours, and then discharge the mixture into n-hexane; The products were collected by filtration, and the collected products were repeatedly washed with n-hexane for 3-5 times and then dried to obtain isocyanate-terminated polyurea oligomers containing a rigid segment structure and isocyanate-terminated polyurea oligomers containing a flexible segment structure, respectively, with chemical structures shown in Formula II and Formula III. Step 3: Add the isocyanate-terminated polyurea oligomer containing a rigid segment structure and the isocyanate-terminated polyurea oligomer containing a flexible segment structure obtained in the second step, an appropriate amount of ethylenediamine, a catalyst dibutyltin dilaurate (DBTDL) and a solvent N,N-dimethylformamide into a three-necked round-bottom flask with a mechanical stirrer, a thermometer and a reflux condenser; under a nitrogen atmosphere, heat the mixture to 80° C. and react for 2 hours, then discharge the mixture into n-hexane; The product was collected by filtration, and the collected product was repeatedly washed with n-hexane for 3-5 times and then dried to obtain an isocyanate-terminated polyurea oligomer with a rigid segment structure and a flexible segment structure interlaced, and the chemical structure is shown in Formula IV Step 4: Add the isocyanate-terminated polyurea oligomer with interlaced rigid segment structure and flexible segment structure obtained above, excess 2-aminoethyl methacrylate and solvent N,N-dimethylformamide into a three-necked round-bottom flask with mechanical stirring, a thermometer and a reflux condenser; under a nitrogen atmosphere, heat the mixture to 60° C. and react for 4 hours, then discharge the mixture into n-hexane; The product was collected by filtration, and the collected product was repeatedly washed with n-hexane for 3-5 times and then dried to obtain a polyurea acrylate photosensitive resin having a rigid segment structure and a flexible segment staggered structure, the chemical structure of which is shown in Formula V 2. The method for preparing a super-tough polyurea acrylate photosensitive resin according to claim 1, characterized in that: In the step 1, the molar ratio of 1,6-hexanediol to diphenylmethane diisocyanate is 1:1.3 to 1:1.

5.

3. The method for preparing a super-tough polyurea acrylate photosensitive resin according to claim 1, characterized in that: In the step 1, the mass fraction of dibutyltin dilaurate is 1% to 3%.

4. The method for preparing a super-tough polyurea acrylate photosensitive resin according to claim 1, characterized in that: In the step 2, the molar ratio of 4,4-diaminodiphenyl sulfone or hexamethylenediamine to the isocyanate-terminated polyurethane prepolymer is 1:1.2 to 1:1.

4.

5. The method for preparing a super-tough polyurea acrylate photosensitive resin according to claim 1, characterized in that: The mass fraction of dibutyltin dilaurate in step three is 1% to 3%.

6. The method for preparing a super-tough polyurea acrylate photosensitive resin according to claim 1, characterized in that: In the step 4, the molar ratio of the isocyanate-terminated polyurea oligomer having staggered rigid segment structures and flexible segment structures to 2-aminoethyl methacrylate is 1:1.1 to 1:1.

3.

7. An ultra-high toughness polyurea acrylate photosensitive resin, characterized in that: The chemical structure is

Images