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CN-122003452-A - Method for recycling polymer and polyol obtained therefrom

CN122003452ACN 122003452 ACN122003452 ACN 122003452ACN-122003452-A

Abstract

A method of recycling polymer waste, polymer polyols prepared by the method, and polyurethanes prepared from the polymer polyols and polyisocyanates are disclosed.

Inventors

  • ZHAO MENGMENG
  • LV XIAOQING
  • A.T. Hadler
  • Wilm, L.F.B.
  • MA JINGCONG
  • GAO LINBO
  • LIU YINGHAO
  • D. Fredank

Assignees

  • 巴斯夫欧洲公司

Dates

Publication Date
20260508
Application Date
20240425
Priority Date
20230809

Claims (17)

  1. 1. A method of recycling polymeric waste, the method comprising: (a) Mixing the polymer waste with a dispersion medium and forming a mixture; (b) Shearing the mixture at a temperature of 160 ℃ to 250 ℃ to form a dispersion of droplets of the polymer waste in a liquid phase; (c) Cooling the dispersion at a temperature of from 0 ℃ to 100 ℃ and obtaining a polymer polyol, Wherein the dispersion medium comprises a polyhydroxy oligomer or polymer selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyols, and any combination thereof.
  2. 2. The method of claim 1, wherein the polymeric waste is selected from the group consisting of polyethylene, polypropylene, polystyrene, poly (methyl methacrylate), polyurethane, polyurea, poly (lactic acid), polybutylene terephthalate, polybutylene adipate terephthalate, and any combination thereof, preferably the polymeric waste is selected from the group consisting of polyurethane, polyurea, poly (lactic acid), polybutylene terephthalate, polybutylene adipate terephthalate, and any combination thereof, more preferably the polymeric waste is polyurethane.
  3. 3. The process of claim 1, wherein the dispersion medium has a total OH number of from 20 to 1,000 mg KOH/g.
  4. 4. The method of claim 1, wherein the polyhydroxy oligomer or polymer has an average functionality of 1.5 to 6.
  5. 5. The method of claim 1, wherein the dispersion medium further comprises an antioxidant selected from the group consisting of sterically hindered phenols and esters thereof.
  6. 6. The method of claim 5, wherein the weight ratio of the antioxidant to the polymeric waste is 1 (20-1000).
  7. 7. The method of claim 1, wherein the dispersion medium is substantially free of any one selected from the group consisting of water, C1-C4 alcohols, acetone, methyl ethyl ketone, acetonitrile, 1, 4-dioxane, pyridine, and tetrahydrofuran.
  8. 8. The method of claim 1, wherein the weight ratio of the polymer waste to the dispersion medium is 1 (0.6-19).
  9. 9. The method of claim 1, wherein the polymer waste and the dispersion medium are mixed by an extruder.
  10. 10. The method of claim 1, wherein the mixture is sheared for a period of 0.5 to 10 hours.
  11. 11. The method of claim 1, wherein the mixture is sheared by a rotating device having a peripheral speed in the range of 10 to 80 s -1 .
  12. 12. The method of claim 11, wherein the rotating device is selected from the group consisting of a stirrer, a rotor-stator, and any combination thereof.
  13. 13. The method of claim 1, further comprising removing at least one impurity from the dispersion prior to step (c).
  14. 14. A polymer polyol prepared by the method of any one of claims 1 to 13.
  15. 15. The polymer polyol of claim 14, wherein the polymer polyol has an average particle size D50 of less than 50 μιη, preferably less than 20 μιη, measured by static laser diffraction according to DIN ISO 9276-2:2018.
  16. 16. The polymer polyol of claim 14, wherein the polymer polyol has a viscosity in the range of 2,000 to 200,000 mPa s at 25 ℃ measured according to DIN EN ISO 3219.
  17. 17. A polyurethane prepared from the polymer polyol of any one of claims 14 to 16 and a polyisocyanate.

Description

Method for recycling polymer and polyol obtained therefrom Background Sustainability has become an increasingly urgent problem as society is facing climate change. Among the many sustainable solutions aimed at carbon neutralization or resource efficiency, the recycling of plastics has attracted interest in the chemical industry. Many polymeric materials, such as polyethylene terephthalate, have been incorporated into the recycling economy by existing physical recycling processes. The process typically melts the thermoplastic and then produces the product. Physical recycling processes typically yield lower grades of product than those produced from virgin polymer. Recycled polymers are typically allowed to be used in applications where lower quality polymers are required. In addition, many polymeric wastes cannot be reused by conventional physical recycling methods for thermoset or other reasons. Chemical recycling, on the other hand, is often accompanied by high construction costs of the facility and extremely high temperatures, corrosiveness, or other dangerous conditions. In addition, some chemical recycling processes (such as transesterification) are selective to the chemical nature of the polymer. Notable examples of chemical recycling include pyrolysis, transesterification, and depolymerization. Some polyols obtained by chemical recycling may contain significant amounts of volatile organic chemicals that are harmful to the environment and health. Thus, what is desired is a method for recycling polymer waste under mild operating conditions and wide polymer versatility. Disclosure of Invention It is an object of the present disclosure to provide a process wherein polymer waste can be converted to polymer polyols. According to one aspect of the present disclosure, a method of recycling polymer waste is provided, the method comprising mixing polymer waste and a dispersion medium and forming a mixture, shearing the mixture at a temperature of 160 ℃ to 250 ℃ to form a dispersion of droplets of the polymer waste in a liquid phase, cooling the dispersion at a temperature of 0 ℃ to 100 ℃ and obtaining a polymer polyol, wherein the dispersion medium comprises a polyhydroxy oligomer or polymer selected from the group consisting of polyester polyols, polyether polyols, polycarbonate polyols, and any combination thereof. According to another aspect of the present disclosure, a polymer polyol prepared by the method is provided. According to yet another aspect of the present disclosure, there is provided a polyurethane prepared from the polymer polyol and a polyisocyanate. The method is simple and does not involve a pressing operation or highly corrosive media. The method is applicable to a wide range of polymer waste, thus reducing the complexity caused by sorting and collecting different kinds of polymers from a composite or final product. Furthermore, the process does not have selectivity for certain classes of polymers. The polymer polyol obtained by this process has a relatively small average particle size, with a uniform particle size distribution, showing little or even no phase separation after storage for a period of, for example, six months. Polyurethanes according to the present disclosure have properties comparable to polyurethanes prepared from petrochemical polyols. Drawings To facilitate recognition of a discussion of any particular element or act, one or more of the most significant digits in a reference numeral refer to the figure number that introduced that element for the first time. FIG. 1 illustrates an aspect of the subject matter according to one embodiment; FIG. 2 illustrates a schematic diagram of a melt emulsification pilot machine in accordance with one embodiment; FIG. 3 shows a photograph of the polymer polyol produced, and Fig. 4 shows a photograph of the polymer polyol of fig. 3 after it has been prepared and stored at room temperature for six months. Detailed Description The term "bimodal" refers to a particle size distribution having two maxima. The term "multimodal" refers to a particle size distribution having three or more maxima. Diameter D10 (x 10,3) defines the particle size at which 10% of the volume of the dispersed phase has particles smaller than the particle size. More detailed description is available in DIN ISO 9276-2, 2009. Diameter D50 (x 50,3) defines the particle size at which 50% of the volume of the dispersed phase has particles smaller than the particle size. More detailed description is available in DIN ISO 9276-2, 2009. Diameter D90 (x 90,3) defines the particle size at which 90% of the volume of the dispersed phase particles are smaller than the particle size. More detailed description is available in DIN ISO 9276-2, 2009. The "index" of the polyurethane-forming composition refers to the ratio of the number of NCO groups present in the polyurethane system to the number of isocyanate-reactive hydrogen atoms, given as a percentage. [ NCO ] is the number of NCO gro