Preparation method of a polyurethane hexaacrylate

Abstract

The present invention discloses a preparation method of polyurethane hexaacrylate. A polyfunctional product is obtained by reacting a diisocyanate with two polyether polyols, which has high reactivity. The obtained product has good hardness, good rigidity and good wear resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and particularly relates to a preparation method of polyurethane hexaacrylate. Background Art

[0002] In recent years, with the enhancement of people's awareness of energy conservation and environmental protection, the variety and performance of photocurable coatings have been continuously enhanced, the application fields have been continuously expanded, and the output has increased rapidly, showing a rapid development trend. Photocurable coatings are not only widely used in various substrates such as paper, plastic, leather, metal, glass, and ceramics, but also successfully applied to materials such as optical fibers, printed circuit boards, and electronic component encapsulation. Polyurethane acrylate synthesized from aromatic isocyanate is called aromatic polyurethane acrylate. Due to the presence of a benzene ring, the chain is rigid, and its cured film has high mechanical strength, good hardness, and heat resistance.

[0003] In the existing invention, the functionality of aromatic polyurethane acrylate is mostly 2-3. The higher the functionality, the better the elasticity and aging resistance of the resin. In the present invention, the functionality of polyurethane acrylate is 6, and the viscosity is 20000-30000 CPS / 25°C. Summary of the Invention

[0004] The present invention discloses a preparation method of polyurethane hexaacrylate. The polyurethane acrylate has a functionality of 6 and has excellent hardness and high wear resistance, and can be mostly used as the main resin in coatings and high-grade photocurable coatings with high performance requirements.

[0005] A preparation method of polyurethane hexaacrylate includes the following steps:

[0006] 1) Put diisocyanate, trimethylolpropane triacrylate, and the inhibitor p-methoxy phenol into a reactor;

[0007] The diisocyanate is one or several of toluene diisocyanate, diphenylmethane diisocyanate, and naphthalene 1,5-diisocyanate. The molar ratio of the diisocyanate to trimethylolpropane triacrylate is 1:2.4, and the p-methoxy phenol accounts for 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate;

[0008] 2) Add polyether at room temperature, and after dropping is completed, control the temperature at 50-80°C and keep it warm for 1-2 hours;

[0009] The polyether is one or several of polypropylene glycol, polypropylene triol, and polytetrahydrofuran glycol. The molar ratio of the polyether to the diisocyanate is 1:1. Preferably, the polyether is a mixture of two polyethers. More preferably, the polyether is a mixture of polyether 210 and polyether 202, and the molar ratio of polyether 210 to polyether 202 is 2-3:1;

[0010] 3) After the heat preservation is completed, p-hydroxyanisole is added again, and stirred for 5 minutes. Then, pentaerythritol triacrylate is added. After the dropping is completed, the temperature is slowly raised, a catalyst is added, and the temperature is slowly raised to 60 - 90 °C and kept warm for 1 - 1.5 hours;

[0011] The p-hydroxyanisole accounts for 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate. The molar ratio of pentaerythritol triacrylate to the diisocyanate in step (1) is 2.4:1;

[0012] The catalyst is one or two of dibutyltin dilaurate, stannous octoate, dibutyltin bis(dodecyl mercaptide), dibutyltin diacetate, triethylamine, N,N-dimethylethanolamine. Preferably, one of dibutyltin dilaurate, stannous octoate, dibutyltin bis(dodecyl mercaptide), dibutyltin diacetate is selected and mixed with one of triethylamine and N,N-dimethylethanolamine. When two catalysts are mixed, the molar ratio of the two catalysts is 1:1;

[0013] The catalyst accounts for 0.02% - 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate.

[0014] 4) After the heat preservation is completed, observe the situation in the kettle and sample for on-site control of NCO%. After passing the inspection, trimethylolpropane triacrylate is added and stirred for about 10 min. After sampling for on-site control and passing the viscosity inspection, it is cooled to below 85 °C and filtered with a 200-mesh filter cloth;

[0015] The molar ratio of the trimethylolpropane triacrylate to the diisocyanate in step (1) is 0.6:1. The present invention achieves the following beneficial technical effects:

[0016] The diisocyanate reacts with two kinds of polyether polyols to obtain a multi-functional product with high reactivity. The obtained product has good hardness, good rigidity and good wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Process flow chart for the preparation of polyurethane hexaacrylate DETAILED DESCRIPTION

[0018] Example 1

[0019] (1) 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p-hydroxyanisole accounting for 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate are put into the reactor;

[0020] (2) 6.8 parts of polyether 210 and 3.2 parts of polyether 202 are added dropwise at a constant speed at room temperature, which takes 30 - 40 min. After the dropping is completed, the temperature is controlled at 50 °C and kept warm for 1 hour;

[0021] (3) After the heat preservation is completed, p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, stirred for 5 minutes, and 24 parts of pentaerythritol triacrylate is added dropwise at a uniform speed, which takes 40 - 60 min. After the addition is completed, the temperature is slowly raised, and dibutyltin dilaurate catalyst accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate is added, and the temperature is slowly raised to 60 °C and kept warm for 1 hour;

[0022] (4) After the heat preservation is completed, sample is taken for in - process control of NCO%. After passing the inspection, 6 parts of trimethylolpropane triacrylate is added, stirred for about 10 min, sample is taken for in - process control. After the viscosity is qualified, it is cooled to below 85 °C and filtered with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0023] Example 2

[0024] (1) 10 parts of diphenylmethane diisocyanate, 24 parts of trimethylolpropane triacrylate, and p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate are put into the reactor;

[0025] (2) At room temperature, 7 parts of polyether 210 and 3 parts of polyether 310 are added dropwise at a uniform speed, which takes 30 - 40 min. After the addition is completed, the temperature is controlled at 80 °C and kept warm for 2 hours;

[0026] (3) After the heat preservation is completed, p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, stirred for 5 minutes, and 24 parts of pentaerythritol triacrylate is added dropwise at a uniform speed, which takes 40 - 60 min. After the addition is completed, the temperature is slowly raised, and bis(dodecylthio)dibutyltin catalyst accounting for 0.05% of the total mass of diisocyanate and trimethylolpropane triacrylate is added, and the temperature is slowly raised to 90 °C and kept warm for 1 hour;

[0027] (4) After the heat preservation is completed, sample is taken for in - process control of NCO%. After passing the inspection, 6 parts of trimethylolpropane triacrylate is added, stirred for about 10 min, sample is taken for in - process control. After the viscosity is qualified, it is cooled to below 85 °C and filtered with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0028] Example 3

[0029] (1) 10 parts of naphthalene - 1,5 - diisocyanate, 24 parts of trimethylolpropane triacrylate, and p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate are put into the reactor;

[0030] (2) At room temperature, 6.8 parts of polyether 210 and 3.2 parts of polyether 202 are added dropwise at a uniform speed, which takes 30 - 40 min. After the addition is completed, the temperature is controlled at 80 °C and kept warm for 2 hours;

[0031] (3) After the heat preservation is completed, add p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate again, stir for 5 minutes, and uniformly dropwise add 24 parts of pentaerythritol triacrylate over 40 - 60 minutes. After the dropping is completed, slowly raise the temperature, add dibutyltin diacetate as a catalyst accounting for 0.08% of the total mass of diisocyanate and trimethylolpropane triacrylate, and slowly raise the temperature to 70 °C for heat preservation for 1 hour;

[0032] (4) After the heat preservation is completed, take a sample for in - process control of NCO%. After passing the inspection, add 6 parts of trimethylolpropane triacrylate, stir for about 10 minutes, take a sample for in - process control. After the viscosity is qualified, cool it to below 85 °C and filter it with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0033] Example 4

[0034] (1) Put 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate into the reactor;

[0035] (2) Uniformly dropwise add 7.5 parts of polyether 202 and 2.5 parts of polyether 310 at room temperature over 30 - 40 minutes. After the dropping is completed, control the temperature at 80 °C for heat preservation for 2 hours;

[0036] (3) After the heat preservation is completed, add p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate again, stir for 5 minutes, and uniformly dropwise add 24 parts of pentaerythritol triacrylate over 40 - 60 minutes. After the dropping is completed, slowly raise the temperature, add stannous octoate as a catalyst accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate, and slowly raise the temperature to 80 °C for heat preservation for 1.5 hours;

[0037] (4) After the heat preservation is completed, take a sample for in - process control of NCO%. After passing the inspection, add 6 parts of trimethylolpropane triacrylate, stir for about 10 minutes, take a sample for in - process control. After the viscosity is qualified, cool it to below 85 °C and filter it with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0038] Example 5

[0039] (1) Put 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate into the reactor;

[0040] (2) Uniformly dropwise add 6.8 parts of polyether 210 and 3.2 parts of polyether 202 at room temperature over 30 - 40 minutes. After the dropping is completed, control the temperature at 50 °C for heat preservation for 1 hour;

[0041] (3) After the heat preservation is completed, p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, stirred for 5 minutes, and 24 parts of pentaerythritol triacrylate is added dropwise at a constant speed, which takes 40 - 60 minutes. After the addition is completed, the temperature is slowly raised, and a catalyst dibutyltin dilaurate and triethylamine accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate are added, wherein the molar ratio of dibutyltin dilaurate to triethylamine is 1:1, and the temperature is slowly raised to 60 °C and kept warm for 2 hours;

[0042] (4) After the heat preservation is completed, the NCO% is sampled and controlled in the middle. After passing the inspection, 6 parts of trimethylolpropane triacrylate are added, stirred for about 10 minutes, sampled and controlled in the middle. After the viscosity is qualified, it is cooled to below 85 °C and filtered with a 200-mesh filter cloth to obtain polyurethane hexaacrylate.

[0043] Example 6

[0044] (1) Put 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate into the reactor;

[0045] (2) At room temperature, 6.8 parts of polyether 210 and 3.2 parts of polyether 202 are added dropwise at a constant speed, which takes 30 - 40 minutes. After the addition is completed, the temperature is controlled at 50 °C and kept warm for 1 hour;

[0046] (3) After the heat preservation is completed, p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, stirred for 5 minutes, and 24 parts of pentaerythritol triacrylate is added dropwise at a constant speed, which takes 40 - 60 minutes. After the addition is completed, the temperature is slowly raised, and a catalyst dibutyltin dilaurate and N,N-dimethylethanolamine accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate are added, wherein the molar ratio of dibutyltin dilaurate to triethylamine is 1∶1, and the temperature is slowly raised to 60 °C and kept warm for 2 hours;

[0047] (4) After the heat preservation is completed, the NCO% is sampled and controlled in the middle. After passing the inspection, 6 parts of trimethylolpropane triacrylate are added, stirred for about 10 minutes, sampled and controlled in the middle. After the viscosity is qualified, it is cooled to below 85 °C and filtered with a 200-mesh filter cloth to obtain polyurethane hexaacrylate.

[0048] Comparative Example 1

[0049] (1) Put 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p-hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate into the reactor;

[0050] (2) At room temperature, 10 parts of polyether 210 are added dropwise at a constant speed, which takes 30 - 40 minutes. After the addition is completed, the temperature is controlled at 50 °C and kept warm for 1 hour;

[0051] (3) After the heat preservation is completed, p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, and stirred for 5 minutes. Then, 24 parts of pentaerythritol triacrylate are added dropwise at a constant speed, which takes 40 - 60 minutes. After the addition is completed, the temperature is slowly raised, and dibutyltin dilaurate catalyst accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate is added, and slowly heated to 60 °C and kept warm for 2 hours;

[0052] (4) After the heat preservation is completed, the NCO% is sampled and controlled in - process. After passing the inspection, 6 parts of trimethylolpropane triacrylate are added, and stirred for about 10 minutes. After sampling and controlling in - process and the viscosity passing the inspection, it is cooled to below 85 °C and filtered with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0053] Comparative Example 2

[0054] (1) 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate are put into the reactor;

[0055] (2) At room temperature, 10 parts of polyether 202 are added dropwise at a constant speed, which takes 30 - 40 minutes. After the addition is completed, the temperature is controlled at 50 °C and kept warm for 1 hour;

[0056] (3) After the heat preservation is completed, p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate is added again, and stirred for 5 minutes. Then, 24 parts of pentaerythritol triacrylate are added dropwise at a constant speed, which takes 40 - 60 minutes. After the addition is completed, the temperature is slowly raised, and dibutyltin dilaurate catalyst accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate is added, and slowly heated to 60 °C and kept warm for 2 hours;

[0057] (4) After the heat preservation is completed, the NCO% is sampled and controlled in - process. After passing the inspection, 6 parts of trimethylolpropane triacrylate are added, and stirred for about 10 minutes. After sampling and controlling in - process and the viscosity passing the inspection, it is cooled to below 85 °C and filtered with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0058] Comparative Example 3

[0059] (1) 10 parts of toluene diisocyanate, 24 parts of trimethylolpropane triacrylate, and p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate are put into the reactor;

[0060] (2) Slowly and evenly add 10 parts of polyether 310 at room temperature over 30 - 40 minutes. After the addition is complete, maintain the temperature at 50 °C for 1 hour.

[0061] (3) After the heat preservation, add p - hydroxyanisole accounting for 0.1% of the total mass of diisocyanate and trimethylolpropane triacrylate, stir for 5 minutes, slowly and evenly add 24 parts of pentaerythritol triacrylate over 40 - 60 minutes. After the addition is complete, slowly raise the temperature, add dibutyltin dilaurate catalyst accounting for 0.02% of the total mass of diisocyanate and trimethylolpropane triacrylate, and slowly raise the temperature to 60 °C and maintain for 2 hours.

[0062] (4) After the heat preservation, take a sample for in - process control of NCO%. After passing the inspection, add 6 parts of trimethylolpropane triacrylate, stir for about 10 minutes, take a sample for in - process control. After the viscosity passes the inspection, cool to below 85 °C and filter with a 200 - mesh filter cloth to obtain polyurethane hexaacrylate.

[0063] Experimental Example 1 NCO%

[0064] Apparatus

[0065] a) Ground - joint Erlenmeyer flask (250 mL):

[0066] b) Analytical balance (sensitivity 0.0001 g): c) Pipette (10 mL):

[0067] d) Acid burette (50 mL);

[0068] e) 100 ml graduated cylinder.

[0069] Reagents and Solutions

[0070] a) 0.1 moL hydrochloric acid standard solution:

[0071] b) Bromophenol blue indicator: concentration 0.4 g / L, 0.04 g bromophenol blue + 100 mL ethanol:

[0072] c) Di - n - butylamine solution: 16.6 g of di - n - butylamine is dissolved in toluene and diluted to 1 L.

[0073] Determination Procedure

[0074] Blank test: Use a pipette to transfer 25 mL of di - n - butylamine solution into an Erlenmeyer flask, add 25 mL of toluene, stir evenly, let stand for half an hour, then add 100 mL of isopropanol, shake well, add (2 - 3) drops of bromophenol blue solution, and titrate with 0.1 mol / L hydrochloric acid standard solution until the color changes from blue - violet to yellow - green, and read the volume of hydrochloric acid standard solution consumed.

[0075] Accurately weigh (2 - 3) g of the sample and place it in a conical flask. Pipette 25 mL of toluene into the flask, shake for 5 min, heat to <50 °C until the sample is completely dissolved. Pipette 25 mL of di-n-butylamine solution into the conical flask, let it stand for half an hour, then add 100 mL of isopropanol, shake well. Then add (2 - 3) drops of bromophenol blue solution, and titrate with 0.1 mo1 / L hydrochloric acid standard solution until the color changes suddenly from blue-violet to yellow-green, and read the volume of the consumed hydrochloric acid standard solution.

[0076] - NC0% (X) is calculated according to formula (1):

[0077] X = (V2 - V1) × C × 4.2 / M.......(1)

[0078] In the formula:

[0079] X - percentage content;

[0080] V1 - the volume of the hydrochloric acid standard solution consumed in titrating the sample:

[0081] V2 - the volume of the hydrochloric acid standard solution consumed in the blank experiment;

[0082] C - the concentration of the hydrochloric acid solution;

[0083] M - the mass number of the sample: g.

[0084] Experimental Example 2 Viscosity CPS / 60 °C

[0085] Single-cylinder rotational viscometer, constant temperature bath, thermometer: with a scale division value of 0.1 °C, low-form beaker

[0086] 1. Fill the beaker with the sample to be measured, ensuring no air bubbles are introduced. If necessary, use vacuum pumping or other suitable methods to eliminate air bubbles. If the sample is volatile or hygroscopic, etc., seal the beaker during the constant temperature process.

[0087] 2. Place the beaker or sample container with the prepared sample into the constant temperature bath, ensuring sufficient time to reach the specified temperature of 60 °C

[0088] 3. Select a suitable rotor and rotation speed, 4# rotor, rotation speed 6

[0089] 4. Start the motor and record the stable reading.

[0090] 5. Stop the motor. After the rotor stops, start the motor again for the second measurement until the deviation of the two consecutive measurement values from the average value is not greater than 3%. Take the average of the two measurement values as the result.

[0091] 6. After the measurement is completed, remove the rotor from the instrument and carefully clean it with a suitable solvent. The result is expressed in Pa·S, taking two significant figures.

[0092] Experimental Example 3 Hardness Test

[0093] Prepare n smooth wooden boards, several glass rods, pencils with different hardnesses (4B - 6H), and one UV curing machine.

[0094] Take 2 - 5 g of the sample and place it on the wooden board. Use the glass rod to spread the sample evenly in the same direction. Then place the wooden board with the applied sample on the UV curing machine to cure the resin. After curing, conduct scratch tests with pencils of different hardnesses.

[0095] The test results of Experimental Examples 1 - 3 are as follows in the table:

[0096]

Claims

1. A preparation method of polyurethane hexaacrylate, characterized in that, It includes the following steps: (1) Put diisocyanate, trimethylolpropane triacrylate, and the polymerization inhibitor p-hydroxyanisole into the reactor; (2) Add polyether at room temperature. After the dropping is completed, keep the temperature at 50 - 80 °C for insulation for 1 - 2 hours; the polyether is a mixed polyether, selected from one of the mixtures of polyether 210 and polyether 202, polyether 210 and polyether 310, and polyether 202 and polyether 310; (3) After the insulation is completed, add p-hydroxyanisole again, stir for 5 minutes, add pentaerythritol triacrylate. After the dropping is completed, slowly raise the temperature, add the catalyst, and slowly raise the temperature to 60 - 90 °C for insulation for 1 - 1.5 hours; (4) After the insulation is completed, observe the situation in the kettle and timely take samples for in-process control of NCO%. After passing the inspection, add trimethylolpropane triacrylate, stir for about 10 minutes, take samples for in-process control. After the viscosity is qualified, cool to below 85 °C and filter with a 200-mesh filter cloth.

2. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The diisocyanate described in step (1) is one or more of toluene diisocyanate, diphenylmethane diisocyanate, and naphthalene 1,5-diisocyanate.

3. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The molar ratio of the diisocyanate and trimethylolpropane triacrylate described in step (1) is 1:2.

4.

4. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The p-hydroxyanisole described in step (1) accounts for 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate.

5. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The polyether described in step (2) is a mixture of polyether 210 and polyether 202, and the molar ratio of polyether 210 to polyether 202 is 2 - 3:

1.

6. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The p-hydroxyanisole described in step (3) accounts for 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate.

7. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The molar ratio of pentaerythritol triacrylate described in step (3) to the diisocyanate in step (1) is 2.4:

1.

8. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The catalyst described in step (3) is one or two of dibutyltin dilaurate, stannous octoate, di(n-dodecylthio)dibutyltin, dibutyltin diacetate, triethylamine, and N,N-dimethylethanolamine. When two catalysts are mixed, the molar ratio of the two catalysts is 1:1, and the catalyst accounts for 0.02% - 0.1% of the total mass of the diisocyanate and trimethylolpropane triacrylate.

9. The preparation method of polyurethane hexaacrylate according to claim 1, characterized in that, The molar ratio of trimethylolpropane triacrylate described in step (4) to the diisocyanate in step (1) is 0.6:1.

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