Bio-based hydrolysis-resistant high-compatibility polyester polyol as well as preparation method and application thereof

Abstract

The invention provides bio-based hydrolysis-resistant high-compatibility polyester polyol as well as a preparation method and application thereof. The polyester polyol is prepared from pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and phthalic anhydride. The molar ratio of the pentaerythritol to the trimethylolpropane to the ricinoleic acid to the dipropylene glycol to the phthalic anhydride is (0.8 to 1.2) to (0.8 to 1.2) to (2.8 to 3.2) to (3.8 to 4.2) to (3.8 to 4.2). The polyester polyol provided by the invention has hydrophobicity, is insensitive to moisture in the curing process, has high functionality, high bonding strength and excellent hydrolysis resistance, and is mutually soluble with common polyether polyol.

Description

Technical Field

[0001] The present invention belongs to the technical field of bio-based materials, and relates to a polyester polyol and its preparation method and application, in particular to a bio-based hydrolysis-resistant and highly compatible polyester polyol and its preparation method and application. Background Art

[0002] Polyester polyols are polymer materials widely used in the production of polyurethane industry. According to raw materials, they include poly(ethylene adipate) glycol-based polyols, polycaprolactone polyols, polycarbonate polyols, PTMEG, PPG, etc. The main function of polyols is to provide soft segments in the polyurethane system, playing a role in endowing polyurethane with elasticity.

[0003] Common polyols include poly(ethylene adipate) glycol-based polyols, polycaprolactone polyols, polycarbonate polyols, PTMEG, PPG, etc. In recent years, with the increasing attention of various countries to environmental protection and the continuous improvement of the performance requirements for polyurethane in the industry, the research and development of bio-based high-performance polyester polyols has become extremely urgent.

[0004] CN104066759B discloses a polyether ester polyol and its preparation method, which is composed of the following raw materials in parts by weight: 405.5 g of trimethylolpropane, 3379.4 g of castor oil, 495.4 g of phthalic anhydride, 1.5 g of imidazole, and 722.5 g of propylene oxide. The preparation method is as follows: 405.5 g of trimethylolpropane, 3379.4 g of castor oil, 495.4 g of phthalic anhydride, and 1.5 g of imidazole are initially fed into a pressure reactor and inerted three times with nitrogen while stirring. Then the reaction mixture is heated to 120°C and mixed with 722.5 g of propylene oxide added within 120 minutes. Once the monomer addition is completed and a constant reaction pressure is reached, volatile substances are distilled out by nitrogen stripping for 30 minutes, and then the product is discharged to obtain 4855 g of polyether ester polyol. The composition of this invention is simple and reasonable, the preparation method is simple, the operation is stable, the prepared polyether ester polyol has good compatibility and excellent hydrolysis resistance. However, the raw materials used in this invention involve flammable and explosive propylene oxide, which is not conducive to industrial production, and the tensile strength and shear resistance are still insufficient, unable to fully meet the requirements of polyurethane structural adhesives.

[0005] Therefore, it is necessary to provide a new polyester polyol to meet the future development needs of polyurethane materials. Summary of the Invention

[0006] In view of the deficiencies of the prior art, the purpose of the present invention is to provide a polyester polyol and its preparation method and application, in particular to provide a bio-based hydrolysis-resistant and highly compatible polyester polyol and its preparation method and application. The polyester polyol of the present invention has hydrophobicity, is insensitive to moisture during the curing process, has a high functionality and high bonding strength, excellent hydrolysis resistance, and is miscible with ordinary polyether polyols.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] On the one hand, the present invention provides a polyester polyol, which is prepared from pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride; the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 0.8 - 1.2:0.8 - 1.2:2.8 - 3.2:3.8 - 4.2:3.8 - 4.2.

[0009] In the present invention, the polyester polyol is prepared from pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride. The polyester polyol has both a long side chain and a benzene ring structure. Such a special structure makes the polyester polyol have strong rigidity while having good low-temperature flexibility, and has excellent compatibility with polyether polyols. In addition, the polyester polyol of the present invention uses bio-derived ricinoleic acid, meeting the environmental protection requirements of sustainable development.

[0010] In the present invention, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 0.8 - 1.2:0.8 - 1.2:2.8 - 3.2:3.8 - 4.2:3.8 - 4.2. Among them, 0.8 - 1.2 in the proportion range of pentaerythritol can be 0.8, 0.9, 1.0, 1.1, or 1.2, etc.; 0.8 - 1.2 in the proportion range of trimethylolpropane can be 0.8, 0.9, 1.0, 1.1, or 1.2, etc.; 2.8 - 3.2 in the proportion range of ricinoleic acid can be 2.8, 2.9, 3.0, 3.1, or 3.2; 3.8 - 4.2 in the proportion range of dipropylene glycol can be 3.8, 3.9, 4.0, 4.1, or 4.2; 3.8 - 4.2 in the proportion range of phthalic anhydride can be 3.8, 3.9, 4.0, 4.1, or 4.2. Preferably, it is 1:1:3:4:4.

[0011] Preferably, the acid value of the polyester polyol is not more than 3 mgKOH / g. For example, its acid value can be 0.5 mgKOH / g, 1.0 mgKOH / g, 1.5 mgKOH / g, 2.0 mgKOH / g, 2.5 mgKOH / g, 2.8 mgKOH / g, etc.

[0012] Preferably, the hydroxyl value of the polyester polyol is 170 to 200 mgKOH / g, such as 170 mgKOH / g, 180 mgKOH / g, 190 mgKOH / g, or 200 mgKOH / g.

[0013] Preferably, the viscosity of the polyester polyol at 25 °C is 4000 to 5000 cps, such as 4000 cps, 4200 cps, 4300 cps, 4400 cps, 4500 cps, 4600 cps, 4700 cps, 4800 cps, 4900 cps, or 5000 cps, etc.

[0014] In a second aspect, the present invention provides a method for preparing the polyester polyol described in the first aspect, and the preparation method includes the following steps:

[0015] Mix pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride, and a catalyst, and carry out an esterification reaction to obtain the polyester polyol.

[0016] Preferably, the temperature of the esterification reaction is 150 to 170 °C, such as 150 °C, 155 °C, 160 °C, 165 °C, or 170 °C, etc., and the time of the esterification reaction is 0.5 to 2 h, such as 0.5 h, 1 h, 1.5 h, or 2 h, etc.

[0017] Preferably, the catalyst includes any one or a combination of at least two of tetrabutyl titanate, stannous octoate, or dibutyltin dilaurate, and tetrabutyl titanate is preferred.

[0018] Preferably, based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride being 100%, the addition amount of the catalyst is 20 to 50 ppm, such as 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, or 50 ppm, etc.

[0019] Preferably, in the esterification reaction, the generated water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor.

[0020] Preferably, after the esterification reaction, the temperature is raised. When the acid value of the system is 8 - 14 mg KOH / g (such as 8 mg KOH / g, 9 mg KOH / g, 10 mg KOH / g, 11 mg KOH / g, 12 mg KOH / g, 13 mg KOH / g or 14 mg KOH / g, etc.) and the viscosity at 25 °C is 3000 - 4000 cps (such as 3000 cps, 3100 cps, 3200 cps, 3300 cps, 3400 cps, 3500 cps, 3600 cps, 3700 cps, 3800 cps or 4000 cps, etc.), vacuum is applied to carry out negative pressure polycondensation reaction. When the acid value of the system is below 3.0 mg KOH / g (such as 0.5 mg KOH / g, 0.8 mg KOH / g, 1.0 mg KOH / g, 1.3 mg KOH / g, 1.6 mg KOH / g, 1.8 mg KOH / g, 2.0 mg KOH / g, 2.5 mg KOH / g or 3.0 mg KOH / g, etc.), the viscosity at 25 °C is 4000 - 5000 cps (such as 4000 cps, 4300 cps, 4600 cps, 4800 cps, 4900 cps or 5000 cps, etc.), and the hydroxyl value is 170 - 200 mg KOH / g (such as 170 mg KOH / g, 175 mg KOH / g, 180 mg KOH / g, 185 mg KOH / g, 190 mg KOH / g, 195 mg KOH / g and mg KOH / g, etc.), the reaction is terminated to obtain the polyester polyol.

[0021] Preferably, the temperature rise is to 210 - 220 °C, such as 210 °C, 212 °C, 214 °C, 216 °C, 218 °C or 220 °C, etc.

[0022] Preferably, the temperature of the negative pressure polycondensation reaction is 220 - 230 °C, such as 220 °C, 222 °C, 224 °C, 226 °C, 228 °C or 230 °C, etc.

[0023] Preferably, the evacuation is carried out by slowly increasing the vacuum degree of the system. The vacuum degree of the system is drawn from -0.04 MPa to -0.09 MPa within 6 - 10 h (such as 6 h, 7 h, 8 h, 9 h or 10 h, etc.). Preferably, the system is maintained at -0.040 MPa to -0.045 MPa (such as -0.040 MPa, -0.041 MPa, -0.042 MPa, -0.043 MPa, -0.044 MPa or -0.045 MPa, etc.) for 1 - 2 h (such as 1 h, 1.5 h or 2 h, etc.), at -0.060 MPa to -0.065 MPa (such as -0.060 MPa, -0.061 MPa, -0.062 MPa, -0.063 MPa, -0.064 MPa or -0.065 MPa, etc.) for 1 - 2 h (such as 1 h, 1.5 h or 2 h, etc.), at -0.080 MPa to -0.085 MPa (such as -0.080 MPa, -0.081 MPa, -0.082 MPa, -0.083 MPa, -0.084 MPa or -0.085 MPa, etc.) for 3 - 4 h (such as 3 h, 3.5 h or 4 h, etc.), and at -0.086 MPa to -0.090 MPa (such as -0.086 MPa, -0.087 MPa, -0.088 MPa, -0.089 MPa or -0.090 MPa, etc.) for 1 - 2 h (such as 1 h, 1.5 h or 2 h, etc.).

[0024] In the present invention, the viscosity of the polyester polyol at 25 °C is 4000 - 5000 cps. The viscosity is controlled by controlling the evacuation time. When the viscosity is less than 4000 cps, the hydroxyl value of the polyester polyol is too high, which is not conducive to the molding of subsequent polyurethane products; when the viscosity is greater than 5000 cps, the hydroxyl value of the polyester polyol is too low, and the high material viscosity is not conducive to subsequent polyurethane production operations.

[0025] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0026] Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are mixed and subjected to an esterification reaction at 150 - 170 °C for 0.5 - 2 h. Then the temperature is raised to 210 - 220 °C. When the acid value of the system is 8 - 14 mgKOH / g and the viscosity at 25 °C is 3000 - 4000 cps, evacuation is slowly carried out for negative pressure polycondensation reaction. When the acid value of the system is below 3.0 mgKOH / g and the viscosity at 25 °C is 4000 - 5000 cps, the reaction is terminated to obtain the polyester polyol;

[0027] The slow evacuation refers to slowly increasing the vacuum degree of the system, evacuating the vacuum degree of the system from -0.04 MPa to -0.09 MPa within 6 to 10 hours. Among them, the system is maintained at -0.040 MPa to -0.045 MPa for 1 to 2 hours, at -0.060 MPa to -0.065 MPa for 1 to 2 hours, at -0.080 MPa to -0.085 MPa for 3 to 4 hours, and at -0.086 MPa to -0.090 MPa for 1 to 2 hours.

[0028] In a third aspect, the present invention provides an application of the polyester polyol described in the first aspect in synthesizing polyurethane (such as polyurethane adhesives or other polyurethanes, etc.) materials.

[0029] Compared with the prior art, the present invention has at least the following beneficial effects:

[0030] (1) The polyester polyol of the present invention is a bio-based polyester polyol, meeting the requirements of sustainable development.

[0031] (2) Due to the special structure of the polyester polyol of the present invention, it has good compatibility with polyether polyols and can be mixed with polyether polyols to meet the usage requirements in different fields.

[0032] (3) The polyester polyol of the present invention has both a long side chain and a benzene ring structure. Such a special structure makes the polyester polyol have strong rigidity and good low-temperature flexibility at the same time.

[0033] (4) The long carbon chain and multifunctionality of the polyester polyol of the present invention make the polyester polyol hydrophobic, insensitive to moisture during the curing process, have high bonding strength, and excellent hydrolysis resistance. Specific Embodiments

[0034] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations to the present invention.

[0035] In the present invention, the acid value is tested according to the test standard GB / T - 6365 - 2006, the hydroxyl value is tested according to the test standard HG / T - 2709 - 2022, and the viscosity is tested using a BROOKFIELD (cone-plate viscometer).

[0036] Example 1

[0037] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0038] (1)Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are charged into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and the catalyst is 1:1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0039] (2)The temperature of the reactor is set at 150 °C, and the esterification reaction is carried out for 1 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor;

[0040] (3)The temperature is further increased to control the reactor temperature at 220 °C, and the reaction is carried out for 4 h. When the acid value of the system is measured to be 10.7 mg KOH / g and the viscosity at 25 °C is 3200 cps, vacuum is prepared for negative pressure polycondensation reaction;

[0041] (4)The vacuum degree of the system is slowly increased from -0.04 MPa to -0.09 MPa, and the vacuum pumping time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mg KOH / g, the viscosity at 25 °C is 4355 cps, and the hydroxyl value is 183.2 mg KOH / g, the reaction is terminated to obtain the polyester polyol.

[0042] Among them, the specific steps of slowly increasing the vacuum degree of the system in step (4) are: maintaining the system at -0.042 MPa for 1 h, maintaining at -0.062 MPa for 1 h, maintaining at -0.082 MPa for 3 h, and maintaining at -0.090 MPa for 1 h.

[0043] Example 2

[0044] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0045] (1)Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are charged into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride is 1.1:1.1:3:4:4; the catalyst is stannous octoate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0046] (2)The temperature of the reactor is set at 160 °C, and the esterification reaction is carried out for 1 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor;

[0047] (3) Continuing to heat up, control the reactor temperature at 220 °C and react for 4 h. The acid value of the system is measured to be 8.2 mg KOH / g, and the viscosity at 25 °C is 3100 cps. Prepare to evacuate the system for negative pressure polycondensation reaction;

[0048] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h, and the temperature of the negative pressure polycondensation reaction is maintained at 220 °C. The acid value of the system is measured to be 2.7 mg KOH / g, the viscosity at 25 °C is 4785 cps, and the hydroxyl value is 173.3 mg KOH / g. End the reaction to obtain the polyester polyol.

[0049] Among them, the specific steps for slowly increasing the system vacuum degree in step (4) are: maintain the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0050] Example 3

[0051] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0052] (1) Put pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst into the reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 1:1:3.1:4.1:4; the catalyst is stannous octoate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride being 100%, the addition amount of the catalyst is 50 ppm;

[0053] (2) Set the reactor temperature to 160 °C and carry out the esterification reaction for 1 h. Discharge the produced water and alcohol at the top of the reactor, and the alcohol refluxes back to the reactor;

[0054] (3) Continuing to heat up, control the reactor temperature at 220 °C and react for 4 h. The acid value of the system is measured to be 5.3 mg KOH / g, and the viscosity at 25 °C is 3900 cps. Prepare to evacuate the system for negative pressure polycondensation reaction;

[0055] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h, and the temperature of the negative pressure polycondensation reaction is maintained at 220 °C. The acid value of the system is measured to be 1.3 mg KOH / g, the viscosity at 25 °C is 4950 cps, and the hydroxyl value is 171.2 mg KOH / g. End the reaction to obtain the polyester polyol.

[0056] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0057] Example 4

[0058] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0059] (1) Put pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 1:1:3:3.8:3.8; the catalyst is stannous octoate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride being 100%, the addition amount of the catalyst is 50 ppm;

[0060] (2) Set the reactor temperature to 160 °C, carry out the esterification reaction for 1 h, discharge the produced water and alcohol at the top of the reactor, and the alcohol refluxes back to the reactor;

[0061] (3) Continue to heat up and control the reactor temperature at 220 °C, react for 4 h, measure the acid value of the system to be 4.7 mgKOH / g, and the viscosity at 25 °C to be 3780 cps, and prepare to evacuate for negative pressure polycondensation reaction;

[0062] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa, the evacuation time is 6 h, the temperature of the negative pressure polycondensation reaction is maintained at 220 °C, measure the acid value of the system to be 1.14 mgKOH / g, the viscosity at 25 °C to be 4970 cps, and the hydroxyl value to be 170.4 mgKOH / g, end the reaction, and obtain the polyester polyol.

[0063] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0064] Example 5

[0065] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0066] (1) Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are put into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and the catalyst is 0.8:1.2:3.2:4.2:4.2; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and phthalic anhydride being 100%, the addition amount of the catalyst is 20 ppm;

[0067] (2) Set the reactor temperature to 170 °C and carry out the esterification reaction for 0.5 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor;

[0068] (3) Continue to raise the temperature and control the reactor temperature at 210 °C. React for 5 h. When the acid value of the system is measured to be 9.78 mg KOH / g and the viscosity at 25 °C is 4500 - 5000 cps, prepare to evacuate for negative pressure polycondensation reaction;

[0069] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 9 h. The temperature of the negative pressure polycondensation reaction is maintained at 220 °C. When the acid value of the system is measured to be 1.33 mg KOH / g, the viscosity at 25 °C is 7758 cps, and the hydroxyl value is 185.3 mg KOH / g, end the reaction to obtain the polyester polyol.

[0070] Among them, the specific steps for slowly increasing the system vacuum degree in step (4) are: maintaining the system at -0.042 MPa for 2 h, at -0.062 MPa for 2 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 2 h.

[0071] Example 6

[0072] In this example, a polyester polyol is provided, and the preparation method includes the following steps:

[0073] (1) Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are put into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and the catalyst is 1:0.8:2.8:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and phthalic anhydride being 100%, the addition amount of the catalyst is 40 ppm;

[0074] (2) Set the reactor temperature to 160 °C and carry out the esterification reaction for 2 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor;

[0075] (3) Continue to raise the temperature and control the reactor temperature at 220 °C. React for 4.5 h. When the acid value of the system is measured to be 10.32 mg KOH / g and the viscosity at 25 °C is 7800 - 8200 cps, prepare to evacuate the system for negative pressure polycondensation reaction;

[0076] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 10 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.76 mg KOH / g, the viscosity at 25 °C is 8636 cps, and the hydroxyl value is 187.32 mg KOH / g, end the reaction to obtain the polyester polyol.

[0077] Among them, the specific steps for slowly increasing the system vacuum degree in step (4) are: maintain the system at -0.042 MPa for 2 h, at -0.062 MPa for 2 h, at -0.082 MPa for 4 h, and at -0.090 MPa for 2 h.

[0078] Comparative Example 1

[0079] In this comparative example, a plasticizer is provided, and the preparation method includes the following steps:

[0080] (1) Put pentaerythritol, castor oil (AVIC, origin: Shandong, model: SDJKFJWJESA), diethylene glycol, phthalic anhydride and a catalyst into the reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, castor oil, diethylene glycol, and phthalic anhydride is 1:1:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, castor oil, diethylene glycol, and phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0081] (2) Set the reactor temperature to 150 °C and carry out the esterification reaction for 1 h. Discharge the produced water and alcohol at the top of the reactor, and the alcohol flows back into the reactor;

[0082] (3) Continue to raise the temperature and control the reactor temperature at 220 °C. React for 4 h. When the acid value of the system is measured to be 10.2 mg KOH / g and the viscosity at 25 °C is 3000 cps, prepare to evacuate the system for negative pressure polycondensation reaction;

[0083] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.53 mg KOH / g, the viscosity at 25 °C is 4000 cps, and the hydroxyl value is 188.7 KOH / g, end the reaction to obtain the polyester polyol.

[0084] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0085] Comparative Example 2

[0086] In this comparative example, a plasticizer is provided, and the preparation method includes the following steps:

[0087] (1) Put pentaerythritol, trimethylolpropane, castor oil (AVIC, origin: Shandong, model: SDJKFJWJESA), 1,6 - hexanediol, adipic acid and a catalyst into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, castor oil, 1,6 - hexanediol, and adipic acid is 1:1:1:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, castor oil, 1,6 - hexanediol, and adipic acid being 100%, the addition amount of the catalyst is 30 ppm;

[0088] (2) Set the reactor temperature to 150 °C, carry out the esterification reaction for 1 h, discharge the produced water and alcohol at the top of the reactor, and the alcohol refluxes into the reactor;

[0089] (3) Continue to heat up and control the reactor temperature at 220 °C, react for 4 h. When the acid value of the system is measured to be 7.23 mg KOH / g and the viscosity at 25 °C is 3560 cps, prepare to evacuate the system for negative compression polymerization reaction;

[0090] (4) Slowly increase the system vacuum degree, pump from -0.04 MPa to -0.09 MPa, the evacuation time is 6 h, the temperature of the negative compression polymerization reaction is maintained at 230 °C. When the acid value of the system is measured to be 0.56 mg KOH / g, the viscosity at 25 °C is 5300 cps, and the hydroxyl value is 170.4 KOH / g, end the reaction to obtain the polyester polyol.

[0091] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0092] Comparative Example 3

[0093] The difference from Example 1 is only that pentaerythritol in step (1) is replaced by 1,6 - hexanediol, specifically:

[0094] (1) Put 1,6 - hexanediol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst into a reactor. Among them, the molar ratio of 1,6 - hexanediol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and the catalyst is 1:1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of 1,6 - hexanediol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0095] (2) Set the reactor temperature to 150 °C and carry out the esterification reaction for 1 h. Discharge the produced water and alcohol at the top of the reactor, and the alcohol flows back into the reactor;

[0096] (3) Continue to heat up and control the reactor temperature at 220 °C for 4 h. When the acid value of the system is measured to be 10.7 mgKOH / g and the viscosity at 25 °C is 3200 cps, prepare to evacuate for negative pressure polycondensation reaction;

[0097] (4) Slowly increase the system vacuum degree from - 0.04 MPa to - 0.09 MPa. The evacuation time is 6 h, and the temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mgKOH / g, the viscosity at 25 °C is 4355 cps, and the hydroxyl value is 183.2 mgKOH / g, end the reaction to obtain the polyester polyol.

[0098] Among them, the specific steps for slowly increasing the system vacuum degree in step (4) are: maintain the system at - 0.042 MPa for 1 h, at - 0.062 MPa for 1 h, at - 0.082 MPa for 3 h, and at - 0.090 MPa for 1 h.

[0099] Comparative Example 4

[0100] The difference from Example 1 is only that the ricinoleic acid in step (1) is replaced by castor oil (AVIC, origin: Shandong, model: SDJKFJWJESA), specifically:

[0101] (1) Put pentaerythritol, trimethylolpropane, castor oil, dipropylene glycol, phthalic anhydride and a catalyst into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, castor oil, dipropylene glycol, phthalic anhydride and the catalyst is 1:1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, castor oil, dipropylene glycol, phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0102] (2) Set the reactor temperature to 150 °C and carry out the esterification reaction for 1 h. Discharge the produced water and alcohol at the top of the reactor, and the alcohol flows back into the reactor;

[0103] (3) Continuing to raise the temperature, control the reactor temperature at 220 °C, react for 4 h. When the acid value of the system is measured to be 10.7 mg KOH / g and the viscosity at 25 °C is 3200 cps, prepare to evacuate for negative pressure polycondensation reaction;

[0104] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mg KOH / g, the viscosity at 25 °C is 3550 cps, and the hydroxyl value is 210.15 mg KOH / g, end the reaction to obtain the polyester polyol.

[0105] Among them, the specific steps for slowly increasing the system vacuum degree in step (4) are: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0106] Comparative Example 5

[0107] The difference from Example 1 is only that dipropylene glycol in step (1) is replaced by diethylene glycol, specifically:

[0108] (1) Put pentaerythritol, trimethylolpropane, ricinoleic acid, diethylene glycol, phthalic anhydride and catalyst into the reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, diethylene glycol, phthalic anhydride and catalyst is 1:1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, diethylene glycol, phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0109] (2) Set the reactor temperature to 150 °C, carry out the esterification reaction for 1 h, discharge the produced water and alcohol at the top of the reactor, and the alcohol flows back to the reactor;

[0110] (3) Continuing to raise the temperature, control the reactor temperature at 220 °C, react for 4 h. When the acid value of the system is measured to be 10.7 mg KOH / g and the viscosity at 25 °C is 3200 cps, prepare to evacuate for negative pressure polycondensation reaction;

[0111] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mg KOH / g, the viscosity at 25 °C is 4355 cps, and the hydroxyl value is 183.2 mg KOH / g, end the reaction to obtain the polyester polyol.

[0112] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0113] Comparative Example 6

[0114] The difference from Example 1 is only that trimethylolpropane is not used in step (1), specifically:

[0115] (1) Pentaerythritol, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are put into a reactor. Among them, the molar ratio of pentaerythritol, ricinoleic acid, dipropylene glycol, phthalic anhydride and the catalyst is 1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, ricinoleic acid, dipropylene glycol and phthalic anhydride being 100%, the addition amount of the catalyst is 30 ppm;

[0116] (2) Set the reactor temperature to 150 °C and carry out the esterification reaction for 1 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol flows back into the reactor;

[0117] (3) Continue to heat up and control the reactor temperature at 220 °C. After reacting for 4 h, when the acid value of the system is measured to be 10.7 mg KOH / g and the viscosity at 25 °C is 4350 cps, prepare to evacuate the system for negative pressure polycondensation reaction;

[0118] (4) Slowly increase the system vacuum degree from -0.04 MPa to -0.09 MPa. The evacuation time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mg KOH / g, the viscosity at 25 °C is 13560 cps, and the hydroxyl value is 128.67 mg KOH / g, end the reaction to obtain the polyester polyol.

[0119] Among them, the specific steps of slowly increasing the system vacuum degree in step (4) are as follows: maintaining the system at -0.042 MPa for 1 h, at -0.062 MPa for 1 h, at -0.082 MPa for 3 h, and at -0.090 MPa for 1 h.

[0120] Comparative Example 7

[0121] The difference from Example 1 is only that phthalic anhydride in step (1) is replaced by adipic acid, specifically:

[0122] (1) Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, adipic acid and a catalyst are put into a reactor. Among them, the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, adipic acid and the catalyst is 1:1:3:4:4; the catalyst is tetrabutyl titanate. Based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol and adipic acid being 100%, the addition amount of the catalyst is 30 ppm;

[0123] (2) The temperature of the reactor is set to 150 °C, and the esterification reaction is carried out for 1 h. The produced water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor;

[0124] (3) The temperature is continuously increased to control the reactor temperature at 220 °C, and the reaction is carried out for 4 h. When the acid value of the system is measured to be 10.7 mgKOH / g and the viscosity at 25 °C is 3200 cps, vacuum is prepared for negative pressure polycondensation reaction;

[0125] (4) The vacuum degree of the system is slowly increased from -0.04 MPa to -0.09 MPa, and the vacuum pumping time is 6 h. The temperature of the negative pressure polycondensation reaction is maintained at 230 °C. When the acid value of the system is measured to be 1.78 mgKOH / g, the viscosity at 25 °C is 4355 cps, and the hydroxyl value is 183.2 mgKOH / g, the reaction is terminated to obtain the polyester polyol.

[0126] Among them, the specific steps for slowly increasing the vacuum degree of the system in step (4) are: maintaining the system at -0.042 MPa for 1 h, maintaining at -0.062 MPa for 1 h, maintaining at -0.082 MPa for 3 h, and maintaining at -0.090 MPa for 1 h.

[0127] Comparative Example 8

[0128] In this comparative example, a commercially available conventional polyester polyol with the brand name HDPOL-4406 and the manufacturer being Shanghai Huide Technology Co., Ltd. is provided

[0129] Comparative Example 9

[0130] In this comparative example, a commercially available polyether ester polyol with the brand name Sovermole805 and the manufacturer being BASF is provided

[0131] Physical property comparison of Application Examples 1-6 and Comparative Application Examples 1-9

[0132] Using Huntsman's polymeric MDI with the brand name 5005, commercially available catalyst T-9, and the polyols of Examples 1-4 and Comparative Examples 1-9, test pieces with a size of 100 mm × 100 mm × 3 mm are made according to the softness. The formulation for making the test pieces is shown in Table 1 below.

[0133] Table 1

[0134]

[0135]

[0136] Specimen preparation: Accurately weigh polycondensed MDI 5005 into a glass beaker, quickly pour the pre-weighed and evenly stirred T-9 and polyol materials into the glass beaker, stir at high speed for 10 seconds, and quickly place it in a vacuum degasser for 10 seconds to remove air bubbles. Then quickly pour it into a pre-prepared polytetrafluoroethylene mold and cure it in an oven at 80 °C for 12 hours to obtain the specimen to be tested.

[0137] (1) Hardness: Tested according to ASTM D2240 standard;

[0138] (2) Tensile strength: Tested according to ASTM D412 standard;

[0139] (3) Tensile modulus: Tested according to ASTM D412 standard;

[0140] (4) Elongation at break: Tested according to ASTM D412 standard.

[0141] The performance test results of the cast specimens in Application Examples 1-6 (using the polyols of Examples 1-6 respectively) and Comparative Application Examples 1-9 (using the polyols of Comparative Examples 1-9 respectively) are shown in Table 2.

[0142] Table 2

[0143]

[0144]

[0145] The cast specimens in Application Examples 1-6 and Comparative Application Examples 1-9 are hydrolyzed in a constant temperature and humidity chamber at a temperature of 85 °C and a humidity of 85% for 72 hours, then the specimens are taken out and kept in an oven at 110 °C for 24 hours to remove water, and after the water removal is completed, the specimens are allowed to cool naturally for 2 hours to test the physical properties.

[0146] The above-mentioned cast specimens are subjected to performance tests, and the test methods are as follows:

[0147] (1) Hardness: Tested according to ASTM D2240 standard;

[0148] (2) Tensile strength: Tested according to ASTM D412 standard

[0149] (3) Tensile modulus: Tested according to ASTM D412 standard

[0150] (4) Elongation at break: Tested according to ASTM D412 standard

[0151] The performance test results of the cast specimen after hydrolysis in the application examples and comparative application examples are shown in Table 3 below.

[0152] Table 3

[0153]

[0154]

[0155] Application Examples 7 - 13 and Comparative Application Examples 10 - 18

[0156] The polyether polyol of Bluestar Dongda with a molecular weight of 2000, grade DL - 2000D, and the polyester polyols of Examples 1 - 6 (corresponding to Application Examples 7 - 13 respectively) and Comparative Examples 1 - 9 (corresponding to Comparative Application Examples 10 - 18 respectively) were thoroughly mixed in a weight ratio of 1:1 for 10 minutes, and their compatibility was tested.

[0157] The compatibility test results of the examples and comparative examples are shown in Table 4 below.

[0158] Table 4

[0159]

[0160]

[0161] As can be seen from Table 2, compared with conventional polyester polyols, the polyester polyol of the present invention has higher physical properties. It can significantly improve the bonding strength of casting materials, crack bridging coatings, floor adhesives, and structural adhesives.

[0162] As can be seen from Table 3, compared with the polyols prepared in the comparative examples and commercially available conventional polyester polyols, the polyester polyol of the present invention has better hydrolysis resistance. It can greatly extend the outdoor service life of polyurethane materials.

[0163] As can be seen from Table 4, compared with the polyols prepared in the comparative examples and commercially available conventional polyester polyols, the polyester polyol of the present invention has better compatibility. It can be used in combination with ordinary polyether polyols, greatly improving the formulation flexibility of polyurethane formulations and enabling them to have a wider range of application scenarios.

[0164] Since the polyester polyol of the present invention uses bio - based ricinoleic acid, it becomes a bio - based polyester polyol, thus better conforming to the environmental protection concept of sustainable development.

[0165] The applicant declares that the polyester polyol, its preparation method and application of the present invention are illustrated by the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc. all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A polyester polyol, characterized in that, The polyester polyol is prepared from pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride; the molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 0.8 - 1.2:0.8 - 1.2:2.8 - 3.2:3.8 - 4.2:3.8 - 4.

2.

2. The polyester polyol according to claim 1, characterized in that, The molar ratio of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride is 1:1:3:4:

4.

3. The polyester polyol according to claim 1 or 2, characterized in that, The acid value of the polyester polyol is not more than 3 mg KOH / g; Preferably, the hydroxyl value of the polyester polyol is 170 - 200 mg KOH / g.

4. The polyester polyol according to any one of claims 1 to 3, characterized in that, The viscosity of the polyester polyol at 25 °C is 4000 - 5000 cps.

5. The preparation method of the polyester polyol according to any one of claims 1-4, characterized in that, The preparation method comprises the following steps: Mix pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride, and a catalyst, and carry out an esterification reaction to obtain the polyester polyol.

6. The preparation method according to claim 5, characterized in that, The temperature of the esterification reaction is 150 - 170 °C, and the time of the esterification reaction is 0.5 - 2 h.

7. The preparation method according to claim 5, characterized in that, The catalyst comprises any one or a combination of at least two of tetrabutyl titanate, stannous octoate, or dibutyltin dilaurate, preferably tetrabutyl titanate; Preferably, based on the total weight of pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, and phthalic anhydride being 100%, the addition amount of the catalyst is 20 - 50 ppm.

8. The preparation method according to any one of claims 5-7, characterized in that, In the esterification reaction, the generated water and alcohol are discharged from the top of the reactor, and the alcohol is refluxed into the reactor; Preferably, after the esterification reaction, the temperature is raised. When the acid value of the system is 8 - 14 mg KOH / g and the viscosity at 25 °C is 3000 - 4000 cps, vacuum is applied for negative pressure polycondensation reaction. When the acid value of the system is below 3.0 mg KOH / g, the viscosity at 25 °C is 4000 - 5000 cps, and the hydroxyl value is 170 - 200 mg KOH / g, the reaction is terminated to obtain the polyester polyol; Preferably, the temperature increase is to 210 - 220 °C; Preferably, the temperature of the negative pressure polycondensation reaction is 220 - 230 °C; Preferably, the vacuum application is to draw the vacuum degree of the system from -0.04 MPa to -0.09 MPa within 6 - 10 h; Preferably, the vacuum application is to maintain the system at -0.040 MPa - 0.045 MPa for 1 - 2 h, at -0.060 MPa - 0.065 MPa for 1 - 2 h, at -0.080 MPa - 0.085 MPa for 3 - 4 h, and at -0.086 MPa - 0.090 MPa for 1 - 2 h.

9. The preparation method according to any one of claims 5-8, characterized in that, The preparation method comprises the following steps: Pentaerythritol, trimethylolpropane, ricinoleic acid, dipropylene glycol, phthalic anhydride and a catalyst are mixed and subjected to an esterification reaction at 150-170°C for 0.5-2 h. Then the temperature is raised to 210-220°C. When the acid value of the system is 8-14 mg KOH / g and the viscosity at 25°C is 3000-4000 cps, vacuum is applied for negative pressure polycondensation reaction. When the acid value of the system is below 3.0 mg KOH / g and the viscosity at 25°C is 4000-5000 cps, the reaction is terminated to obtain the polyester polyol; The vacuum application is to pump the vacuum degree of the system from -0.04 MPa to -0.09 MPa within 6-10 h. Among them, the system is maintained at -0.040 MPa to -0.045 MPa for 1-2 h, at -0.060 MPa to -0.065 MPa for 1-2 h, at -0.080 MPa to -0.085 MPa for 3-4 h, and at -0.086 MPa to -0.090 MPa for 1-2 h.

10. Use of the polyester polyol according to any one of claims 1-4 in the synthesis of polyurethane materials.

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