Preparation method of castor oil modified polycarbonate diol
Through the thiol-ene click reaction and the deacid bonding of acid chloride and hydroxyl groups, the castor oil polycarbonate diol was modified to solve the problem of poor high temperature resistance in high temperature environments by the existing bio-based aqueous polyurethane emulsion, and the effect of the modified product showing excellent performance at high temperatures is achieved.
Patent Information
- Application Number
- CN202411859214.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-02-28
AI Technical Summary
The existing bio-based aqueous polyurethane emulsions show poor high temperature resistance in high temperature environments, limiting their application in high-end products and harsh environments.
By using mercaptoethanol as a hydroxyl expander, the unsaturated double bond of castor oil is realized based on the thiol-ene click reaction, and the unsaturated double bond to the hydroxyl group is achieved, and component A is obtained. Then, using the acid chloride compound containing two terminal acid chloride groups as the crosslinking agent, component A and the crosslinking agent are added dropwise to the polycarbonate diol based on the deacid bonding of the acid chloride and the hydroxyl group to complete the modification of the polycarbonate diol by castor oil.
After the modified castor oil polycarbonate diol is prepared as a polyol, it shows excellent high temperature resistance and is suitable for high-end products and harsh environments.
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polyols, and particularly relates to a method for preparing castor oil-modified polycarbonate diol. Background Art
[0002] Waterborne polyurethane emulsion (WPU) refers to a new type of polyurethane system that uses water instead of organic solvent as a dispersion medium. It is widely used in adhesives, coatings and other industries due to its many advantages such as green, environmentally friendly and good compatibility. Among them, according to the different soft segment raw materials in the preparation process of waterborne polyurethane emulsion, waterborne polyurethane emulsion can be roughly divided into polyester waterborne polyurethane emulsion, polyether waterborne polyurethane emulsion, bio-based waterborne polyurethane emulsion and polycarbonate diol waterborne polyurethane emulsion. Compared with other types, bio-based waterborne polyurethane emulsion can better fit the original intention of waterborne coatings, but the existing bio-based waterborne polyurethane emulsion still has certain disadvantages, which limits its actual application effect; this is because most of these bio-based waterborne polyurethane emulsions are prepared with a single castor oil as a polyol (i.e., soft segment raw material), which often leads to the final obtained film. Most of its performance is not as good as that of polyester, polyether and polycarbonate diol types, especially high temperature resistance, which seriously limits its use in high-end products and harsh environments. Summary of the invention
[0003] In view of the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing castor oil-modified polycarbonate diol. The present invention creatively uses mercaptoethanol as a hydroxyl extender, so that it reacts with the unsaturated double bonds of castor oil based on a mercapto-ene click reaction, realizes the conversion of the unsaturated double bonds in the molecular structure of castor oil to hydroxyl groups, and then obtains component A; then an acyl chloride compound containing two terminal acyl chloride groups is used as a crosslinking agent, and based on the deacidification bonding of the acyl chloride and the hydroxyl group, component A and the crosslinking agent are added dropwise to the polycarbonate diol, that is, the modification of the polycarbonate diol by castor oil is completed, and the corresponding modified product is obtained. When the modified product is used as a polyol to prepare an aqueous polyurethane emulsion, it can have excellent performance, especially good high temperature resistance, and is very practical.
[0004] The purpose of the present invention can be achieved through the following technical solutions:
[0005] A method for preparing castor oil-modified polycarbonate diol, the method comprising the following steps:
[0006] S1: Stir castor oil, mercaptoethanol and benzoin dimethyl ether for 5-10 minutes at room temperature, then stir for 1-2 hours under ultraviolet light at 45-50°C, cool naturally to room temperature, filter, take the filtrate, and distill under reduced pressure to obtain component A;
[0007] S2: Stir tetrahydrofuran and polycarbonate diol at room temperature for 15-30 minutes to mix, then add the acyl chloride compound and component A dropwise while stirring in a nitrogen atmosphere under an ice bath, add sodium hydroxide solution after all the additions are completed, continue stirring at room temperature for 2-3 hours to mix, distill under reduced pressure, cool, filter, and take the filtrate to complete the preparation.
[0008] As a preferred technical solution of the present invention, the mass ratio of the castor oil, the mercaptoethanol and the benzoin dimethyl ether in S1 is 10:5-6:1.
[0009] As a preferred technical solution of the present invention, the irradiation with ultraviolet light in S1 refers to irradiation with ultraviolet light having a wavelength of 365 nm.
[0010] As a preferred technical solution of the present invention, the reduced pressure distillation in S1 refers to distillation at 60-70°C under a vacuum degree of -0.06 MPa until the volatiles are completely removed.
[0011] As a preferred technical solution of the present invention, the mass ratio of the tetrahydrofuran, the polycarbonate diol, the acyl chloride compound and the component A in S2 is 80:2:0.2-0.3:0.8-1.
[0012] As a preferred technical solution of the present invention, the dripping of the acyl chloride compound and component A in S2 refers to dripping the acyl chloride compound at a rate of 2-4s / drop, and dripping component A at a rate of 4-6s / drop.
[0013] As a preferred technical solution of the present invention, the acyl chloride compound in S2 is at least one of succinyl chloride, adipoyl chloride and sebacoyl chloride.
[0014] As a preferred technical solution of the present invention, the mass fraction of the sodium hydroxide solution in S2 is 8-10%; the mass ratio of the sodium hydroxide solution to the acyl chloride compound is 3:2-2.5.
[0015] As a preferred technical solution of the present invention, the reduced pressure distillation in S2 refers to distillation at 55° C. under a vacuum degree of -0.04 MPa until the volatiles are completely removed.
[0016] As a preferred technical solution of the present invention, the cooling in S2 refers to cooling to 3-5°C.
[0017] Beneficial effects of the present invention:
[0018] (1) The present invention creatively uses mercaptoethanol as a hydroxyl extender, so that it reacts with the unsaturated double bonds of castor oil based on a mercapto-ene click reaction, thereby realizing the conversion of the unsaturated double bonds in the molecular structure of castor oil to hydroxyl groups, and then obtaining component A. Then, an acyl chloride compound containing two terminal acyl chloride groups is used as a crosslinking agent, and based on the deacidification bonding of the acyl chloride and the hydroxyl group, component A and the crosslinking agent are added dropwise to polycarbonate diol, thus completing the modification of polycarbonate diol by castor oil. When the modified product is used as a polyol to prepare an aqueous polyurethane emulsion, it can have excellent high temperature resistance.
[0019] (2) The present invention creatively prepares a modified product of castor oil-modified polycarbonate diol, so that after it is used as a polyol to prepare an aqueous polyurethane emulsion, it can have excellent performance, especially good high temperature resistance. On the one hand, the castor oil part in the modified product is a polyhydroxy molecular structure with a high degree of branching, which can provide a large number of active sites for reacting with isocyanate groups, has high cohesive energy, and has a good contribution to high temperature resistance; on the other hand, the polycarbonate diol part in the modified product contains carbonate groups, which can not only form a conjugated structure, improve rigidity, and promote high temperature resistance, but also form hydrogen bonds with the hard segment to enhance thermal stability. At the same time, compared with the physical modification of simple blending, chemical modification can better exert the synergistic effect of the two. In addition, in the process of modification, the dripping method is very critical. Whether the polycarbonate diol and the crosslinking agent are dripped into component A, or the crosslinking agent is dripped into the mixture of component A / polycarbonate diol, good technical effects cannot be obtained. The possible reason is that the molecular weight of polycarbonate diol is relatively high, the hydroxyl content is relatively low, and the chemical activity is not as good as castor oil. As a result, these two dropping methods promote the cross-linking of components A, and there are not many target modified products. DETAILED DESCRIPTION
[0020] In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in combination with the embodiments.
[0021] The polycarbonate diols in all the embodiments and comparative examples of the present invention are purchased from Asahi Chemical Industry Co., Ltd., with the brand name T-5652.
[0022] Example 1
[0023] A method for preparing castor oil-modified polycarbonate diol, the method comprising the following steps:
[0024] S1: Stir castor oil, mercaptoethanol and benzoin dimethyl ether at room temperature for 5 minutes, then stir for 1 hour under ultraviolet light at 45°C, cool naturally to room temperature, filter, take the filtrate, and distill under reduced pressure to obtain component A;
[0025] S2: Tetrahydrofuran and polycarbonate diol are stirred at room temperature for 15 minutes to mix, and then the acyl chloride compound and component A are added dropwise while stirring in a nitrogen atmosphere under an ice bath. After all the additions are completed, sodium hydroxide solution is added, and stirring is continued for 2 hours at room temperature. The mixture is distilled under reduced pressure, cooled, filtered, and the filtrate is taken to complete the preparation.
[0026] The mass ratio of the castor oil, the mercaptoethanol and the benzoin dimethyl ether in S1 is 10:5:1.
[0027] The irradiation with ultraviolet light in S1 refers to irradiation with ultraviolet light having a wavelength of 365 nm.
[0028] The reduced pressure distillation in S1 refers to distillation at 60° C. under a vacuum degree of −0.06 MPa until the volatiles are completely removed.
[0029] The mass ratio of the tetrahydrofuran, the polycarbonate diol, the acyl chloride compound and the component A in S2 is 80:2:0.2:0.8.
[0030] The dripping of the acyl chloride compound and component A in S2 means dripping the acyl chloride compound at a rate of 2 s / drop, and dripping component A at a rate of 4 s / drop.
[0031] The acyl chloride compound in S2 is succinyl chloride.
[0032] The mass fraction of the sodium hydroxide solution in S2 is 8%; the mass ratio of the sodium hydroxide solution to the acyl chloride compound is 3:2.
[0033] The reduced pressure distillation in S2 refers to distillation at 55° C. under a vacuum degree of −0.04 MPa until the volatiles are completely removed.
[0034] The cooling in S2 refers to cooling to 3°C.
[0035] Example 2
[0036] A method for preparing castor oil-modified polycarbonate diol, the method comprising the following steps:
[0037] S1: Stir castor oil, mercaptoethanol and benzoin dimethyl ether for 10 min at room temperature, then stir for 2 h under ultraviolet light at 50°C, cool naturally to room temperature, filter, take the filtrate, and distill under reduced pressure to obtain component A;
[0038] S2: Stir tetrahydrofuran and polycarbonate diol at room temperature for 30 minutes to mix, then add the acyl chloride compound and component A dropwise while stirring in a nitrogen atmosphere under an ice bath, add sodium hydroxide solution after all the additions are completed, continue stirring for 3 hours at room temperature, distill under reduced pressure, cool, filter, and take the filtrate to complete the preparation.
[0039] The mass ratio of the castor oil, the mercaptoethanol and the benzoin dimethyl ether in S1 is 10:6:1.
[0040] The irradiation with ultraviolet light in S1 refers to irradiation with ultraviolet light having a wavelength of 365 nm.
[0041] The reduced pressure distillation in S1 refers to distillation at 70° C. under a vacuum degree of −0.06 MPa until the volatiles are completely removed.
[0042] The mass ratio of the tetrahydrofuran, the polycarbonate diol, the acyl chloride compound and the component A in S2 is 80:2:0.3:1.
[0043] The dripping of the acyl chloride compound and component A in S2 means dripping the acyl chloride compound at a rate of 4 s / drop, and dripping component A at a rate of 6 s / drop.
[0044] The acyl chloride compound in S2 is succinyl chloride.
[0045] The mass fraction of the sodium hydroxide solution in S2 is 10%; the mass ratio of the sodium hydroxide solution to the acyl chloride compound is 3:2.5.
[0046] The reduced pressure distillation in S2 refers to distillation at 55° C. under a vacuum degree of −0.04 MPa until the volatiles are completely removed.
[0047] The cooling in S2 refers to cooling to 5°C.
[0048] Example 3
[0049] A method for preparing castor oil-modified polycarbonate diol, the method comprising the following steps:
[0050] S1: Stir castor oil, mercaptoethanol and benzoin dimethyl ether at room temperature for 8 minutes, then stir for 1.5 hours under ultraviolet light at 48°C, cool naturally to room temperature, filter, take the filtrate, and distill under reduced pressure to obtain component A;
[0051] S2: Stir tetrahydrofuran and polycarbonate diol at room temperature for 20 minutes to mix, then add the acyl chloride compound and component A dropwise while stirring in a nitrogen atmosphere under an ice bath, add sodium hydroxide solution after all the additions are completed, continue stirring at room temperature for 2.5 hours to mix, distill under reduced pressure, cool, filter, and take the filtrate to complete the preparation.
[0052] The mass ratio of the castor oil, the mercaptoethanol and the benzoin dimethyl ether in S1 is 10:5.5:1.
[0053] The irradiation with ultraviolet light in S1 refers to irradiation with ultraviolet light having a wavelength of 365 nm.
[0054] The reduced pressure distillation in S1 refers to distillation at 65° C. under a vacuum degree of −0.06 MPa until the volatiles are completely removed.
[0055] The mass ratio of the tetrahydrofuran, the polycarbonate diol, the acyl chloride compound and the component A in S2 is 80:2:0.25:0.9.
[0056] The dripping of the acyl chloride compound and component A in S2 means dripping the acyl chloride compound at a rate of 3 s / drop, and dripping component A at a rate of 5 s / drop.
[0057] The acyl chloride compound in S2 is succinyl chloride.
[0058] The mass fraction of the sodium hydroxide solution in S2 is 9%; the mass ratio of the sodium hydroxide solution to the acyl chloride compound is 3:2.3.
[0059] The reduced pressure distillation in S2 refers to distillation at 55° C. under a vacuum degree of −0.04 MPa until the volatiles are completely removed.
[0060] The cooling in S2 refers to cooling to 4°C.
[0061] Comparative Example 1
[0062] On the basis of Example 3, component A in S2 was changed to castor oil of equal weight, and the rest remained unchanged.
[0063] Comparative Example 2
[0064] On the basis of Example 3, the acyl chloride compound in S2 was replaced by an equal weight of tetrahydrofuran, the sodium hydroxide solution was replaced by an equal weight of tetrahydrofuran, and the rest remained unchanged.
[0065] Comparative Example 3
[0066] On the basis of Example 3, S2 is changed to stir tetrahydrofuran and component A at room temperature for 20 minutes to mix, and then add the acyl chloride compound and polycarbonate diol dropwise while stirring in a nitrogen atmosphere under an ice bath, the dropping rate of the acyl chloride compound is controlled at 3s / drop, and the dropping rate of the polycarbonate diol is controlled at 5s / drop. After all the dropwise additions are completed, sodium hydroxide solution is added, and stirring is continued for 2.5h at room temperature to mix, and reduced pressure distillation, cooling, filtering, and taking the filtrate are completed; the rest remain unchanged.
[0067] Comparative Example 4
[0068] On the basis of Example 3, S2 is changed to stir tetrahydrofuran, polycarbonate diol and component A at room temperature for 20 minutes, then add the acyl chloride compound dropwise while stirring in a nitrogen atmosphere under an ice bath, and the dropping rate of the acyl chloride compound is controlled at 3s / drop. After all the dropwise addition is completed, sodium hydroxide solution is added, and stirring is continued for 2.5h at room temperature, and the mixture is distilled under reduced pressure, cooled, filtered, and the filtrate is taken, and the preparation is completed; the rest remains unchanged.
[0069] Test Example 1
[0070] High temperature resistance test:
[0071] The castor oil-modified polycarbonate diol prepared in Example 3 and Comparative Examples 1-4 and castor oil (blank group) were used as polyols to prepare aqueous polyurethane emulsions, respectively. The steps were as follows: 55 parts by weight of polyol and 45 parts by weight of isophorone diisocyanate were stirred and mixed at 80° C. under a nitrogen atmosphere for 2 h, naturally cooled to 50° C., kept warm, 20 parts by weight of acetone, 4 parts by weight of 2,2-dimethylolpropionic acid and 3 parts by weight of 1,4-butanediol were added, and stirring and mixing were continued for 6 h. Then, triethylamine was added dropwise while stirring until the neutralization degree was 100%, and the dropping rate was controlled at 2 drops / s. After the dropping was completed, deionized water was added, and finally, the mixture was stirred and mixed at a stirring speed of 1000 r / min at room temperature for 60 min, and the mixture was distilled under reduced pressure until the acetone was completely removed, thereby obtaining an aqueous polyurethane emulsion (solid content of 40%).
[0072] The aqueous polyurethane emulsion was poured into a polytetrafluoroethylene plate tank, and then cured at room temperature for 72 hours, and finally dried at 45° C. until constant weight was obtained to obtain a film with a thickness of 100 μm.
[0073] The decomposition temperature of the film was tested by a thermogravimetric analyzer under the following test conditions: nitrogen atmosphere, heating rate of 10°C / min to 500°C, and the temperature when the mass loss reached 3% was recorded as the decomposition temperature (rounded to the nearest integer).
[0074] Table 1 High temperature resistance test results
[0075] Decomposition temperature / ℃ Example 3 236 Comparative Example 1 231 Comparative Example 2 220 Comparative Example 3 227 Comparative Example 4 224 Castor oil (blank group) 209
[0076] From the comparison between Test Example 1, Example 3, Comparative Examples 1-4 and the blank group, it can be seen that the castor oil-modified polycarbonate diol prepared by the present invention can obtain a more excellent high temperature resistance effect after being used as a polyol to prepare an aqueous polyurethane emulsion.
[0077] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.
Claims
1. A method for preparing castor oil-modified polycarbonate diol, characterized in that: The preparation method comprises the following steps: S1: Stir castor oil, mercaptoethanol and benzoin dimethyl ether for 5-10 minutes at room temperature, then stir for 1-2 hours under ultraviolet light at 45-50°C, cool naturally to room temperature, filter, take the filtrate, and distill under reduced pressure to obtain component A; S2: Stir tetrahydrofuran and polycarbonate diol at room temperature for 15-30 minutes to mix, then add the acyl chloride compound and component A dropwise while stirring in a nitrogen atmosphere under an ice bath, add sodium hydroxide solution after all the additions are completed, continue stirring at room temperature for 2-3 hours to mix, distill under reduced pressure, cool, filter, and take the filtrate to complete the preparation.
2. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The mass ratio of the castor oil, the mercaptoethanol and the benzoin dimethyl ether in S1 is 10:5-6:
1.
3. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The irradiation with ultraviolet light in S1 refers to irradiation with ultraviolet light having a wavelength of 365 nm.
4. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The reduced pressure distillation in S1 refers to distillation at 60-70° C. under a vacuum degree of −0.06 MPa until the volatiles are completely removed.
5. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The mass ratio of the tetrahydrofuran, the polycarbonate diol, the acyl chloride compound and the component A in S2 is 80:2:0.2-0.3:0.8-1.
6. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The dripping of the acyl chloride compound and component A in S2 refers to dripping the acyl chloride compound at a rate of 2-4 s / drop, and dripping component A at a rate of 4-6 s / drop.
7. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The acyl chloride compound in S2 is at least one of succinyl chloride, adipoyl chloride and sebacoyl chloride.
8. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The mass fraction of the sodium hydroxide solution in S2 is 8-10%; the mass ratio of the sodium hydroxide solution to the acyl chloride compound is 3:2-2.
5.
9. The method for preparing a castor oil-modified polycarbonate diol according to claim 1, characterized in that: The reduced pressure distillation in S2 refers to distillation at 55° C. under a vacuum degree of −0.04 MPa until the volatiles are completely removed.
10. The method for preparing castor oil-modified polycarbonate diol according to claim 1, characterized in that: The cooling in S2 refers to cooling to 3-5°C.