Search

US-12617920-B2 - Polyurethane foams recycling methods and systems

US12617920B2US 12617920 B2US12617920 B2US 12617920B2US-12617920-B2

Abstract

A polyurethane foam product is formed into a plurality of polyurethane masses. The plurality of polyurethane masses are fed into an extruder with a thermoplastic polymer urethane thermoplastic elastomer. The plurality of polyurethane masses are blended with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature to produce a recycled polyurethane product. The weight ratio of the plurality of polyurethane masses to the thermoplastic polymer urethane thermoplastic elastomer exceeds about 50:50.

Inventors

  • Vahid Serajian
  • Sahand Serajian

Assignees

  • Edge Global Innovation Inc.

Dates

Publication Date
20260505
Application Date
20220819

Claims (20)

  1. 1 . A method for recycling a polyurethane foam product comprising: heating the polyurethane foam product under compression at a temperature of at least about 180° C. and a pressure of at least about 200 psi for a sufficient time without solvent to densify the polyurethane foam product and form a polyurethane layer structure selected from a sheet or a film; converting the densified polyurethane layer structure into a plurality of polyurethane masses; feeding the plurality of polyurethane masses into an extruder with a thermoplastic polymer urethane thermoplastic elastomer; and blending the plurality of polyurethane masses with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature without solvent to produce a recycled polyurethane product; wherein the weight ratio of the plurality of polyurethane masses to the thermoplastic polymer urethane thermoplastic elastomer exceeds about 25:75.
  2. 2 . The method of claim 1 , wherein the converting includes at least one of grinding the densified polyurethane layer structure and shredding the densified polyurethane layer structure.
  3. 3 . The method of claim 2 , wherein the converting includes cryogenically grinding the densified polyurethane layer structure.
  4. 4 . The method of claim 1 , wherein the densified polyurethane layer structure is converted into the plurality of polyurethane masses by grinding.
  5. 5 . The method of claim 1 , wherein the densified polyurethane layer structure is converted into the plurality of polyurethane masses by shredding.
  6. 6 . The method of claim 1 , wherein the heating includes vitrimerization of the polyurethane foam product.
  7. 7 . The method of claim 1 , wherein the plurality of polyurethane masses include at least one of a plurality of polyurethane foam flakes and a plurality of polyurethane foam particles.
  8. 8 . The method of claim 1 , wherein the polyurethane foam product includes at least one of a toluene diisocyanate based urethane foam and a methylene diphenyl diisocyanate based foam.
  9. 9 . The method of claim 1 , wherein the thermoplastic polymer urethane thermoplastic elastomer is selected from aliphatic or aromatic thermoplastic polyurethane or their prepolymers.
  10. 10 . The method of claim 1 , wherein the polyurethane foam product is a mattress.
  11. 11 . The method of claim 1 , wherein the polyurethane foam product includes a catalyst.
  12. 12 . The method of claim 1 , further comprising: adding a catalyst to the extruder during at least one of the feeding and the blending.
  13. 13 . The method of claim 12 wherein the catalyst is a urethane catalyst selected from the group consisting of zinc-based catalysts, titanium-based catalysts, tin-based catalysts and bismuth-based catalysts.
  14. 14 . The method of claim 1 , further comprising: adding a polymer processing additive selected from the group consisting of antioxidants, waxes, thermal stabilizers, ultraviolet stabilizers, biocides and fillers to the extruder during the blending.
  15. 15 . A method for preparing a polyurethane foam product for transport, the method comprising: heating the polyurethane foam product with a heat press to an elevated temperature of at least about 180° C. without solvent; applying an elevated pressure of at least about 200 psi to the polyurethane foam product within the heat press while the polyurethane foam product is at the elevated temperature without solvent; holding the polyurethane foam product in the heat press at the elevated pressure and elevated temperature and sufficient time without solvent to form a vitrimerized and densified polyurethane layer structure selected from the group consisting of a sheet and a film.
  16. 16 . The method of claim 15 , further comprising: converting the polyurethane layer structure into a plurality of polyurethane masses selected from the group consisting of flakes, particles, and pellets.
  17. 17 . A method for recycling a polyurethane foam product comprising: heating the polyurethane foam product under compression at a temperature of at least about 180° C. and a pressure of at least about 200 psi for a sufficient time without solvent to densify the polyurethane foam product and form a polyurethane layer structure selected from a sheet or a film; converting the densified polyurethane layer structure into a plurality of polyurethane masses; feeding the plurality of polyurethane masses into a melt processing tool with a thermoplastic polymer urethane thermoplastic elastomer; and blending the plurality of polyurethane masses with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature without solvent to produce a recycled polyurethane product; wherein the weight ratio of the plurality of polyurethane masses to the thermoplastic polymer urethane thermoplastic elastomer exceeds about 50:50.
  18. 18 . The method of claim 17 , wherein the melt processing tool is a melt processing tool selected from the group consisting of an injection molder, a compounder, and an internal mixer.
  19. 19 . The method of claim 17 , wherein converting the densified polyurethane layer structure into the plurality of polyurethane masses comprises cryogenically grinding the polyurethane layer structure to form polyurethane particles.
  20. 20 . The method of claim 17 , further comprising adding at least one polymer processing additive to the melt processing tool during blending, wherein the polymer processing additive is selected from the group consisting of antioxidants, waxes, thermal stabilizers, ultraviolet stabilizers, biocides, and fillers.

Description

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a U.S. national stage application of PCT International Application No. PCT/US22/40888, filed Aug. 19, 2022, which claims priority to U.S. Patent Application No. 63/235,194, filed on Aug. 20, 2021. The disclosures of all the foregoing applications are hereby incorporated by reference in their entirety into the present application. TECHNICAL FIELD The subject disclosure is directed to systems, methods, and apparatus for recycling polyurethane materials and, more particularly, methods and systems for recycling and reusing post-industrial and post-consumer or scrap polyurethane foams, especially polyurethane foam mattresses. BACKGROUND ART Thermosets are covalently cross-linked networks that, unlike thermoplastics cannot be reprocessed by melting or dissolution in any solvents. These networks can exhibit a glass transition temperature (Tg) lower than the designed application service temperature (elastomer/rubber) or higher than the service temperature (thermoset resins). Thermoset rubbers find applications in the automotive industry (interiors, bumpers), biomedical devices, bedding, furniture, packaging, gaskets, O-rings and so on. Usually, thermoset resins exhibit significant benefits in comparison with thermoplastics exhibiting dimensional stability, high mechanical properties, high thermal/creep/and chemical resistance, durability. This class of polymers maintain their structural strength, thermal and electrical resistance characteristics during prolonged use. Thermosets find many industrial uses as coatings, adhesives, and other applications. Commercial applications include applications in energy production, manufacturing of light vehicles, structural materials for buildings, pipelines, industrial equipment and/or their components for instance heat exchangers, light-emitting diode lenses, flywheels for electricity grid stability, containers, or off-shore structures in which composite materials are the material of choice. Polyurethanes, specifically polyurethane foams such as mattress and cushions represent a particular class of thermoset materials that present significant challenges with respect to recycling and/or to re-use of post-consumer or scrap materials. Such foams are partially landfilled or incinerated for energy recovery. A small portion of such foam is used for carpeting. Some methods, such as chemical recycling, utilize catalysts and solvent swelling methods to recycle thermoset polyurethane waste and scrap. Such methods involve reversible reactions (transesterification and carbamate exchange) and depolymerization of polyurethane. Unfortunately, the use of catalysts and solvents to reprocess the thermoset can increase the complexity and the cost of the recycling process. Other methods utilize thermal reprocessing of polyurethane foams by impregnating the materials with catalyst through solvent swelling or direct mixing. The catalyst is necessary to facilitate the reversible carbamate exchange reactions. The resultant mechanical properties were poor. Accordingly, there is a need for method and system to reuse and to reprocess post-consumer or scrap polyurethane thermoset foams that is solvent free with acceptable mechanical properties than can be used in various consumer applications. DISCLOSURE OF INVENTION In various implementations, a method for recycling a polyurethane foam product is provided. The polyurethane foam product is formed into a plurality of polyurethane masses. The plurality of polyurethane masses are fed into an extruder with a thermoplastic polymer urethane thermoplastic elastomer. The plurality of polyurethane masses are blended with the thermoplastic polymer urethane thermoplastic elastomer at an elevated temperature to produce a recycled polyurethane product. The weight ratio of the plurality of polyurethane masses to the thermoplastic polymer urethane thermoplastic elastomer exceeds about 25:75. The elevated temperature is at least about 180° C. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a system in accordance with this disclosure. FIG. 2 is an exemplary process in accordance with this disclosure. FIG. 3 is a schematic diagram of another embodiment of a system in accordance with this disclosure. FIG. 4 is another exemplary process in accordance with this disclosure. MODES FOR CARRYING OUT THE INVENTION The subject disclosure is directed to methods and systems for recycling polyurethane materials and, more particularly, methods and systems for recycling and reusing post-industrial and post-consumer or scrap polyurethane foams, especially polyurethane foam mattresses. The detailed description provided below in connection with the appended drawings is intended as a description of examples and is not intended to represent the only forms in which the present examples can be constructed or utilized. The description sets forth functions of the examples and sequences of steps for constructing