Purification method of polycarbonate-polyether polyol and product obtained by using polycarbonate-polyether polyol

Abstract

The invention belongs to the technical field of high-molecular compound purification, and relates to a purification method of polycarbonate-polyether polyol and a product obtained by using the same. The invention relates to a purification method of polycarbonate-polyether polyol, which comprises the following steps: (1) adding a composite adsorbent and an additive into a polycarbonate-polyether polyol crude product to be purified, and stirring to obtain a mixture of the polycarbonate-polyether polyol crude product and the adsorbent; and (2) filtering the mixture, adding an antioxidant, rectifying and dehydrating to obtain the product. The purification method of polycarbonate-polyether polyol provided by the invention is almost transparent and colorless, and can improve the metal removal rate. The Co content in the purified product is not higher than 4 ppm, and the Al content is not higher than 5 ppm; the chromaticity L * is not lower than 66.0, a * is not higher than 0.15, and b * is not higher than 2.0; the moisture content is not higher than 0.06%.

Description

Technical Field

[0001] This invention belongs to the field of polymer purification technology, specifically relating to a purification method for polycarbonate-polyether polyols and the products obtained therefrom. Background Technology

[0002] Polycarbonate polyether polyol (PCE) is a random block copolymer of polycarbonate and polyether, prepared by copolymerizing carbon dioxide and epoxy compounds under the action of a catalyst. This polymer possesses both the high modulus, high hydrogen bond density, and high weather resistance and abrasion resistance inherent in carbonate bonds, and the flowability and flexibility inherent in ether bonds. However, most crude polyether polyols obtained through polymerization contain metal ions (such as Al). 3+ Co 2+ Substances such as aldehydes, low-molecular-weight polymers, and unreacted olefin oxides produced by side reactions can cause polyether polyols to exhibit abnormal color or a tendency to produce irritating odors. Furthermore, the catalyst remains in the system throughout the entire reaction process; residual catalyst not only affects the product's color and transparency but also its use and storage. Excessive catalyst residue can cause PCE to decompose during storage, generating volatile byproducts and reducing the polymer's heat resistance. Therefore, removing byproducts and residues from the reaction process is a pressing problem that needs to be solved.

[0003] Relevant patent documents retrieved: For example, Chinese patent CN115368548A, published on December 1, 2023, discloses a purification method and purified product of polycarbonate polyether polyol, including the following steps: adding raw materials to a composite adsorbent and stirring to adsorb to obtain a mixture; feeding the mixture into a pressure filtration system and filtration to obtain purified polycarbonate polyether polyol; the composite adsorbent, based on the total amount of polymer, includes 0.03-10 wt% activated carbon, 0.03-10 wt% magnesium aluminum silicate, 0.03-10 wt% diatomaceous earth, and 0-1.5 wt% antioxidant. This invention addresses the issue of residual catalyst in high-viscosity polycarbonate polyether polyols with a carbonate group molar fraction ≥50%. It utilizes the synergistic effect of diatomaceous earth, activated carbon, magnesium aluminum silicate, and antioxidants to purify and filter the polycarbonate polyether polyol. This method rapidly removes catalyst residue while maintaining filtration speed, reducing energy consumption, and controlling processing time and cost. The removal rates of cobalt and zinc in the product can reach up to 99%, and the product has a clean color, good luster, and high transparency. However, the removal rate of byproducts generated during the reaction process needs improvement.

[0004] Relevant non-patent literature retrieved: The journal or book title is "Guangzhou Chemical Industry," and the document title is "Purification and Refining Process of Polycarbonate Polyether Polyols," volume number 2024, 52(20):27-29. This document discloses a purification method for polycarbonate polyether polyols, which provides a highly efficient metal catalyst adsorption removal scheme for purifying and refining polycarbonate polyether polyols. After purification, the metal removal rate in the polycarbonate polyether polyol can reach over 98%, and its Lab color is L* = 68.41, a* = 0.03, b* = 1.50, almost transparent and colorless. This method can realize the industrialization of polycarbonate polyether polyol refining, enabling polycarbonate polyether polyols to be widely used in downstream polyurethane products. However, this study also has the aforementioned problems.

[0005] Therefore, there is an urgent need to provide a purification method for polycarbonate-polyether polyols to remove byproducts and residues from the reaction process. Summary of the Invention

[0006] The purpose of this invention is to provide a method for purifying polycarbonate-polyether polyols and the product obtained therefrom, as well as related technologies, to solve technical problems such as the presence of byproducts and residues during the reaction process, or a combination thereof.

[0007] Terminology Explanation: Unless otherwise defined, all technical terms in this document have the same meanings as commonly understood by one of ordinary skill in the art to which the subject matter of the claims pertains. Unless otherwise stated, all patents, patent inventions, and publications cited in this document are incorporated herein by reference in their entirety. If multiple definitions exist for terms in this document, the definitions in this chapter shall prevail.

[0008] It should be understood that the above brief description and the following detailed description are exemplary and for illustrative purposes only, and do not limit the subject matter of the invention in any way. In this invention, the singular is used in conjunction with the plural unless otherwise specifically stated. It should also be noted that, unless otherwise stated, the use of “or” or “or” means “and / or”. Furthermore, the use of the term “comprising” and other forms such as “including,” “containing,” and “contains” are not limiting.

[0009] The definition of standard chemical terms can be found in the reference "Modern Separation, Purification and Analysis Techniques: Applications in Polymer Materials Research", University of Science and Technology of China Press, Gao Sulian (Chief Editor), June 2004.

[0010] Unless specifically defined herein, the use of all commercially available products herein employs standard techniques. For example, it may be carried out using the manufacturer's instructions for use with the kit, or in accordance with methods known in the art or the description of this invention. The techniques and methods described herein can generally be implemented according to conventional methods well known in the art, based on the descriptions in the various summary and more specific documents cited and discussed in this specification.

[0011] In a first aspect, the present invention provides a method for purifying polycarbonate-polyether polyols, comprising the following steps: (1) Add composite adsorbent and additive to the crude polycarbonate-polyether polyol product to be purified, and stir to obtain a mixture of crude polycarbonate-polyether polyol product and adsorbent; (2) Filter the mixture, add antioxidants, distill and dehydrate to obtain the final product.

[0012] Preferably, the amount of composite adsorbent added in step (1) is 2-5% of the total mass of the crude polycarbonate-polyether polyol product to be purified, more preferably 3%.

[0013] Preferably, the composite adsorbent in step (1) is composed of magnesium silicate and nano-sized hydroxyapatite (HAP) in a mass ratio of 2-4:1, more preferably 3:1.

[0014] Preferably, the specific surface area of ​​the magnesium silicate is ≥300m². 2 / g.

[0015] Preferably, the amount of the additive added is 0.2-1% of the total mass of the crude polycarbonate-polyether polyol product to be purified, more preferably 0.5%.

[0016] Preferably, the additive in step (1) is selected from at least one of polydimethylsiloxane composite material loaded with silver nanoparticles, modified sepiolite, and hydrotalcite, to inhibit the yellowing phenomenon caused by product oxidation at high temperature. The preparation method of the PDMS composite material loaded with silver nanoparticles is as follows: silver nitrate and polydimethylsiloxane are mixed at 60-80°C, ethanol is added as a reducing agent, and Ag-PDMS is generated in situ in the PDMS matrix.

[0017] Preferably, the mass ratio of silver nitrate to polydimethylsiloxane is 1:10-15, more preferably 1:12.

[0018] Preferably, the amount of ethanol added is 20-50 mL, more preferably 30 mL.

[0019] Preferably, a filter aid is added during the filtration process in step (2), and the filter aid is selected from at least one of perlite, diatomaceous earth, magnesium sulfate, and polyacrylamide.

[0020] More preferably, the filter aid used in step (2) is perlite, and the amount of filter aid added is 0.1%-0.5% of the total mass of the crude polycarbonate-polyether polyol product to be purified, more preferably 0.3%.

[0021] Preferably, the distillation in step (2) is carried out under reduced pressure at 80-120°C.

[0022] More preferably, the distillation in step (2) is carried out under reduced pressure at 100°C.

[0023] Preferably, the antioxidant in step (2) is di-tert-butyl-p-cresol with a mass fraction of 0.05-0.2% of the total mass of the crude polycarbonate-polyether polyol product to be purified, more preferably 0.1% di-tert-butyl-p-cresol.

[0024] Secondly, the present invention provides a purification method for obtaining polycarbonate-polyether polyol, wherein the polycarbonate-polyether polyol obtained after purification has a Co content of not more than 4 ppm, an Al content of not more than 5 ppm, a color L* of not less than 66.0, a* of not more than 0.15, b* of not more than 2.0, and a moisture content of not more than 0.06%. The polycarbonate-polyether polyol can be obtained by the following purification method, which includes the following steps: (1) adding a composite adsorbent and an additive to the crude polycarbonate-polyether polyol to be purified, and stirring to obtain a mixture of the crude polycarbonate-polyether polyol and the adsorbent; (2) filtering the mixture, adding an antioxidant, and distilling to remove water, thereby obtaining the final product.

[0025] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a purification method for polycarbonate-polyether polyols. In the embodiments of the present invention, the purified polycarbonate-polyether polyols have a Co content of no more than 4 ppm, an Al content of no more than 5 ppm, a color (L*) of no less than 66.0, a* of no more than 0.15, and b* of no more than 2.0, and are almost transparent and colorless; the moisture content is no more than 0.06%. This method enables the industrialization of polycarbonate-polyether polyol purification, allowing polycarbonate-polyether polyols to be widely used in downstream polyurethane products. Detailed Implementation

[0026] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0027] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all instruments, devices, equipment, reagents, products, etc., used in the embodiments of the present invention are obtained through conventional commercial means.

[0028] The nano-sized hydroxyapatite used was purchased from Merck Life Sciences Ltd., CAS number 12167-74-7.

[0029] The silver nanoparticle-loaded polydimethylsiloxane composite material (Ag-PDMS) was prepared by the following method: silver nitrate and polydimethylsiloxane were mixed at a mass ratio of 1:12 at 70°C, and 30 mL of ethanol was added as a reducing agent to generate Ag-PDMS in situ in the PDMS matrix.

[0030] Example 1: A purification method for polycarbonate-polyether polyols The specific steps are as follows: (1) Add 15g of composite adsorbent (magnesium silicate and nano-hydroxyapatite in a mass ratio of 3:1) and 2.5g of Ag-PDMS to 500g of crude polycarbonate-polyether polyol to be purified, and stir to obtain a mixture of crude polycarbonate-polyether polyol and adsorbent. (2) The mixture was filtered by adding 1.5g of perlite in a circular screen filter, and then 5g of di-tert-butyl-p-cresol was added. The mixture was then distilled under reduced pressure at 100℃ to obtain the purified polycarbonate-polyether polyol.

[0031] Example 2: A purification method for polycarbonate-polyether polyols The difference from Example 1 is that the mass ratio of magnesium silicate to nano-hydroxyapatite is 2:1, while the rest is the same as in Example 1.

[0032] Example 3: A purification method for polycarbonate-polyether polyols The difference from Example 1 is that the mass ratio of magnesium silicate to nano-hydroxyapatite is 4:1, while the rest is the same as in Example 1.

[0033] Example 4: A purification method for polycarbonate-polyether polyols The difference from Example 1 is that the amount of composite adsorbent added is 10g, while the rest is the same as in Example 1.

[0034] Example 5: A purification method for polycarbonate-polyether polyols The difference from Example 1 is that the amount of composite adsorbent added is 25g, while the rest is the same as in Example 1.

[0035] Example 6: A purification method for polycarbonate-polyether polyols The difference from Example 1 is that the amount of Ag-PDMS added is 1g, otherwise it is the same as Example 1. Example 7: A method for purifying polycarbonate-polyether polyols. The difference from Example 1 is that the amount of Ag-PDMS added is 5g, while the rest is the same as in Example 1.

[0036] Example 8 The difference from Example 1 is that Ag-PDMS is replaced with modified sepiolite, and everything else is the same as in Example 1.

[0037] Example 9 The difference from Example 1 is that Ag-PDMS is replaced with hydrotalcite, and everything else is the same as in Example 1.

[0038] Comparative Example 1 The difference from Example 1 is that the composite adsorbent consists of 2.5g magnesium aluminum silicate, 2.5g activated carbon and 5g diatomaceous earth, while the rest is the same as in Example 1.

[0039] Comparative Example 2 The difference from Example 1 is that the mass ratio of magnesium silicate to nano-hydroxyapatite is 1:3, while the rest is the same as in Example 1.

[0040] Comparative Example 3 The difference from Example 1 is that nano-sized hydroxyapatite is replaced with activated carbon, while the rest is the same as Example 1.

[0041] Comparative Example 4 The difference from Example 1 is that Ag-PDMS is not added; otherwise, it is the same as Example 1.

[0042] Effect Experiment 1. Analysis of Metal Residue Results To examine the catalyst removal, accurately weigh 1 g (accurate to 0.0001 g) of the product prepared in each example and comparative example, and accurately record the weight M. PCEThe products prepared in each example and comparative example were placed in a 100 mL crucible, sealed, and preheated in an electric heating mantle to convert the liquid into a solid. Sealing prevents Al and Co from being introduced into the air along with combustion gases or smoke, causing errors. Typically, a lid is used. The crucible containing the analyte is then placed in a muffle furnace, heated to 500 °C for 2 hours, and held at that temperature for 2 hours to ensure complete ashing of the sample, leaving Al and Co residues on the lid and walls of the crucible. The remaining Al and Co in the crucible are then dissolved in an acid solution and prepared as a solution in a 100 mL volumetric flask. The solution is then tested using an inductively coupled plasma atomic emission spectrometer (ICP, Plasma 1500). The residual amounts of the metal catalyst are shown in Table 1.

[0043] Table 1

[0044] As can be seen from the data in Table 1, the purification effect of the embodiments of the present invention is good. The Zn content in the purified products is all below 4 ppm and the Co content is all below 5 ppm, which can meet the needs of most application scenarios.

[0045] 2. Lab colorimetric analysis The color change of the purified product was investigated using Lab colorimetric analysis. First, 5g of the analyte was weighed and placed in a cuvette. The cuvette was placed in a dark environment to minimize the influence of light sources on the test and reduce errors. An NR10QC colorimeter was used for testing, and the test data included three basic coordinates: L*, a*, and b*. The coordinate L* represents the color brightness, with L* = 0 indicating black and L* = 100 indicating white. The coordinate a* represents the position between red / magenta and green, with a negative value indicating green and a positive value indicating magenta. Where the coordinate b* represents the position between yellow and blue, a negative b* indicates blue, and a positive b* indicates yellow. When a* and b* approach 0, the sample is closer to colorless.

[0046] The results are shown in Table 2.

[0047] Table 2

[0048] As can be seen from the data in Table 2, the product obtained by the purification method in this embodiment of the invention is nearly colorless, and the purification effect is good.

[0049] 3. Moisture content determination The test was conducted according to the method of national standard GB / T6283-2008, and the results are shown in Table 3.

[0050] Table 3

[0051] As can be seen from the data in Table 3, the purification method of this invention produces a product with low moisture content and good purification effect.

[0052] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for purifying polycarbonate-polyether polyols, characterized in that, Includes the following steps: (1) Add composite adsorbent and additive to the crude polycarbonate-polyether polyol product to be purified, and stir to obtain a mixture of crude polycarbonate-polyether polyol product and adsorbent; (2) Filter the mixture, add antioxidants, and distill to remove water, thus obtaining the final product; The composite adsorbent described in step (1) includes magnesium silicate and nano-sized hydroxyapatite.

2. The purification method according to claim 1, characterized in that, The amount of composite adsorbent added in step (1) is 2-5% of the total mass of the crude polycarbonate-polyether polyol product to be purified.

3. The purification method according to claim 1, characterized in that, The mass ratio of magnesium silicate and nano-sized hydroxyapatite in step (1) is 2-4:

1.

4. The purification method according to claim 1, characterized in that, The additive mentioned in step (1) is selected from at least one of polydimethylsiloxane composite material loaded with silver nanoparticles, modified sepiolite, and hydrotalcite; the amount of the additive added is 0.2-1% of the total mass of the crude polycarbonate-polyether polyol product to be purified.

5. The purification method according to claim 4, characterized in that, The preparation method of the polydimethylsiloxane composite material loaded with silver nanoparticles is as follows: silver nitrate and polydimethylsiloxane are mixed at 60-80°C, and ethanol is added as a reducing agent to generate the polydimethylsiloxane composite material loaded with silver nanoparticles in situ in the polydimethylsiloxane matrix.

6. The purification method according to claim 5, characterized in that, The mass ratio of silver nitrate to polydimethylsiloxane is 1:10-15.

7. The purification method according to claim 1, characterized in that, In step (2), a filter aid is added during the filtration process. The filter aid is selected from at least one of perlite, diatomaceous earth, magnesium sulfate, and polyacrylamide.

8. The purification method according to claim 1, characterized in that, The distillation described in step (2) is carried out under reduced pressure at 80-120℃.

9. The purification method according to claim 1, characterized in that, The antioxidant mentioned in step (2) is di-tert-butyl-p-cresol, with a mass fraction of 0.05-0.2% of the total mass of the crude polycarbonate-polyether polyol product to be purified.

10. A polycarbonate-polyether polyol obtained by a purification method, characterized in that, The purified polycarbonate polyether polyol has a Co content of no more than 4 ppm and an Al content of no more than 5 ppm; a color L* of no less than 66.0, a* of no more than 0.15, b* of no more than 2.0; and a moisture content of no more than 0.06%. The polycarbonate-polyether polyol is obtained by the following purification method: (1) Add a composite adsorbent and additives to the crude polycarbonate-polyether polyol to be purified and stir to obtain a mixture of crude polycarbonate-polyether polyol and adsorbent; (2) Filter the mixture, add an antioxidant, distill and dehydrate to obtain the final product.

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