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US-12617893-B2 - Method for manufacture of polyesters with recycle content

US12617893B2US 12617893 B2US12617893 B2US 12617893B2US-12617893-B2

Abstract

A method for the manufacture of polyesters with recycle content by feeding to at least one reaction zone recycle feed comprising an ester recycle material selected from the group consisting of r-DMT, transesterified r-DMT and combinations thereof to form a reaction mixture comprising recycled content in at least one reaction zone; reacting the reaction mixture to form a polyester oligomer mixture with recycled content; and polycondensing the recycle content oligomer mixture to form a polyester with recycle content; wherein the feeding step further comprises feeding to at least one reaction zone a virgin feed, the virgin feed including at least one virgin diol component, the virgin feed further comprises a virgin diacid component, and the virgin diacid component is at least 90 mole % terephthalic acid based on the total diacid content of the virgin feed; and wherein the reacting step comprises reacting the reaction mixture at a temperature of at least 250° C. for a total average residence time of between 30 minutes and 12 hours.

Inventors

  • Earl Edmondson Howell, Jr.
  • Michael Paul Ekart
  • Travis Wynn Keever
  • Bob N. Jack
  • Jonathan Michael Horton
  • Daniel Lee Martin

Assignees

  • EASTMAN CHEMICAL COMPANY

Dates

Publication Date
20260505
Application Date
20201216

Claims (15)

  1. 1 . A method for manufacture of polyesters with recycle content, said method comprising the steps of feeding to at least one reaction zone recycle feed comprising an ester recycle material selected from the group consisting of r-DMT, transesterified r-DMT and combinations thereof to form a reaction mixture comprising recycled content in said at least one reaction zone; reacting said reaction mixture to form a polyester oligomer mixture with recycled content; and polycondensing said recycle content oligomer mixture to form a polyester with recycle content; wherein said feeding step further comprises feeding to at least one reaction zone a virgin feed, said virgin feed including at least one virgin diol component, said virgin feed further comprises a virgin diacid component, and said virgin diacid component is at least 90 mole % terephthalic acid based on the total diacid content of said virgin feed; and wherein said reacting step comprises reacting said reaction mixture at a temperature of at least 250° C. for a total average residence time of between 30 minutes and 12 hours.
  2. 2 . The method of claim 1 wherein said feeding step further comprises feeding to at least one reaction zone a diol recycle material selected from the group consisting of r-EG, r-DEG and combinations thereof.
  3. 3 . The method of claim 1 wherein said recycle feed further comprises dimethyl isophthalate recycle material (r-DMI).
  4. 4 . The method of claim 1 wherein said recycle feed further comprises residual catalyst material selected from the group consisting of germanium materials and antimony materials and combinations thereof.
  5. 5 . The method of claim 1 wherein said virgin diacid component comprises one or both of terephthalic acid and isophthalic acid.
  6. 6 . The method of claim 1 wherein reacting step is performed in the presence of a metal-based catalyst with the metal of said metal-based catalyst selected from the group consisting of Sb, Ti, Sn, Mo, Ge, Zn, Co, Mn, Cd, Al, Li, Pb, Mg, Ca, Ag, Na, Ce, Ba, Hg, Fe, Cu and combinations thereof.
  7. 7 . The method of claim 1 wherein said virgin diol component of said virgin feed includes one or more of ethylene glycol, 1,3-propane diol, 1,4-butane diol, 1,5-pentane diol, 1,6-hexane diol, 1,7-heptane diol, 1,8-octane diol, 1,10-decane diol, diethylene glycol, triethylene glycol, polyethylene glycols, polytetrahydrofurans, polyoxymethylenes, isosorbide, 1,3- and 1,4-cyclohexane dimethanol (CHDM), 1,4-cyclohexane dimethanol, 2,2,4,4-tetraalkylcyclobutane diols including 2,2,4,4-tetramethylcyclobutane diol (TMCD), neopentyl glycol, 2,2,4-trimethyl-1,3-pentane diol, glycerol, trimethylolpropane, pentaerylthritol, resorcinol, hydroquinone and catechol and isomers and combinations thereof.
  8. 8 . The method of claim 1 wherein said diol component of said virgin feed includes one or more diols selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), cyclohexanedimethanol (CHDM) and isomers and combinations thereof.
  9. 9 . The method of claim 1 further comprising, prior to said feeding step, the step of depolymerizing a waste polyester to form a depolymerization product comprising r-DMT; and wherein said depolymerization step is performed by methanolysis.
  10. 10 . The method of claim 1 wherein said ester recycle material of said feeding step is fed in an amount sufficient to account for 1 to 100 mole % based on total moles diacid of 1,4-dicarboxybenzene equivalents in said polyester with recycled content.
  11. 11 . The method of claim 1 wherein said step of feeding said virgin feed precedes said step of feeding said recycle feed; and wherein said method further includes the step of reacting at least some of said virgin feed in said reactor to form virgin polyester oligomer prior to or concurrent with the step of feeding said recycle feed.
  12. 12 . The method of claim 1 further comprising, prior to said feeding step, the step of pre-reacting at least some of said r-DMT with one or more diols selected from the group consisting of diols selected from the group consisting of ethylene glycol, diethylene glycol, neopentyl glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, cyclohexanedimethanol, ethylene glycol, 2,2,4,4-tetramethyl-1,4-cyclobutanediol and isomers and combinations thereof to form a trans-esterified r-DMT.
  13. 13 . The method of claim 12 wherein said pre-reacting step is performed in the presence of a metal-based catalyst with the metal of said metal-based catalyst selected from the group consisting of Sb, Ti, Sn, Mo, Ge, Zn, Co, Mn, Cd, Al, Li, Pb, Mg, Ca, Ag, Na, Ce, Ba, Hg, Fe, Cu and combinations thereof.
  14. 14 . A recycle feed composition for manufacture of polyesters with recycle content, said recycle feed comprising: ester recycle material selected from the group consisting of r-DMT, transesterified r-DMT and combinations thereof; r-TPA and at least one of dimethyl isophthalate recycle material (r-DMI); and residual catalyst material selected from the group consisting of germanium materials and antimony materials and combinations thereof.
  15. 15 . The recycle feed composition of claim 14 wherein said recycle feed composition comprises dimethyl isophthalate recycle material (r-DMI) in an amount of 3000 ppm or more; or wherein said residual catalyst material is present in the amount of 5 to 500 ppm based on part of said feed composition.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a national stage filing under 35 USC § 371 of International Application Number PCT/US2020/065256, filed on Dec. 16, 2020 which claims the benefit of the filing date to U.S. Provisional Application No. 62/950,619, filed on Dec. 19, 2019, the entire disclosures of which are incorporated by reference herein. FIELD OF THE INVENTION The present disclosure generally relates to the fields of polyester recycle and polyester manufacture and more particularly to polyester manufacturing processes that include use of the methanolysis reaction products in forming polyesters with recycle content. BACKGROUND OF THE INVENTION Polyesters are one of the world's most purchased and diversely utilized class of polymers, with published world production volumes (including recycling) recently reported to be well in excess of 75 million tons. This level of commercial success is likely attributable in part to polyesters' attractive combination of relative cost, manufacturability and competitive performance attributes. Polyester's physical, chemical and thermal properties make them useful and desirable for a wide variety of end-use applications. Polyethylene terephthalate (PET) is one of the most popular types of polyester for many end-uses. With the continuing commercial success of polyesters generally and PET specifically have come efforts to recover materials from post-consumer, post-industrial, scrap and other sources and re-use those materials as an alternative to basic disposal methods such as landfills. In one known recycle method, recycled PET is blended with virgin materials. This approach has been used, for example, to prepare blends of virgin poly(butylene terephthalate) (“PBT”) with recycled PET to yield a PBT-based product with recycle content (see, for example, U.S. Patent Published Patent Application No. 2009/0275698). Such blends, however, can be generally immiscible and produce a material that is relatively opaque. Blending, therefore, is not a uniformly satisfactory method to provide commercially valuable end products with recycle content. In another recycle method, polyesters are depolymerized to form the monomer units originally used in its manufacture. One commercially utilized method for polyester depolymerization is methanolysis. In methanolysis, the polyester is reacted with methanol to produce a depolymerized polyester mixture comprising polyester oligomers, dimethyl terephthalate (“DMT”), and ethylene glycol (“EG”). Other monomers such as, for example, 1,4-cyclohexanedimethanol (“CHDM”) and diethylene glycol may also be produced depending on the composition of the polyester in the methanolysis feed stream. Some representative methods for the methanolysis of PET are described in U.S. Pat. Nos. 3,037,050; 3,321,510; 3,776,945; 5,051,528; 5,298,530; 5,414,022; 5,432,203; 5,576,456 and 6,262,294, the contents and disclosure of which are each incorporated herein by reference. A representative methanolysis process is also illustrated in U.S. Pat. No. 5,298,530, the contents and disclosure of which are incorporated herein by reference. The '530 patent describes a process for the recovery of ethylene glycol and dimethyl terephthalate from scrap polyester. The process includes the steps of dissolving scrap polyester in oligomers of ethylene glycol (EG) and terephthalic acid (TPA) or dimethyl terephthalate (DMT) and passing super-heated methanol through this mixture. The oligomers can comprise any low molecular weight polyester polymer of the same composition as that of the scrap material being employed as the starting component such that the scrap polymer will dissolve in the low molecular weight oligomer. The dimethyl terephthalate and the ethylene glycol are recovered from the methanol vapor stream that issues from depolymerization reactor. Uses of the monomer units generated via depolymerization, in particular DMT and EG, are continuously being investigated by manufacturers with a goal of producing and selling new materials with recycled content. For example, the assignee of the present disclosure generally proposes in U.S. Published Patent Application No. 2013/0041053 that recycled monomers such as DMT can be combined with virgin monomers in polyester manufacture. The proposal, however, has its drawbacks. First, it contemplates operation of the esterification/transesterification step at temperatures, typically, about 150° C. to about 250° C. for about 0.5 to about 8 hours and at pressures ranging from about 0.0 kPa gauge to about 414 kPa gauge (60 pounds per square inch, psig). Such conditions are not aligned with operational conditions suitable for current-day terephthalic-acid-based (TPA-based) polyester manufacturing processes in which the feed is substantially devoid of purposefully added esters and includes only diacids, predominantly terephthalic acid, and one or more glycols. Achieving recycle content by incorporation of recycles materials such