WO2000039205A1 - Recovery of recyclable material from a physical combination of it and normally solid poly(alkylene carbonate) material - Google Patents

Recovery of recyclable material from a physical combination of it and normally solid poly(alkylene carbonate) material Download PDF

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Publication number
WO2000039205A1
WO2000039205A1 PCT/US1999/031132 US9931132W WO0039205A1 WO 2000039205 A1 WO2000039205 A1 WO 2000039205A1 US 9931132 W US9931132 W US 9931132W WO 0039205 A1 WO0039205 A1 WO 0039205A1
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Prior art keywords
poly
thε
alkylene carbonate
matεrial
normally
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PCT/US1999/031132
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French (fr)
Inventor
Alexander F. Giacco
Joseph G. Sant'angelo
Xiaomao Chen
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Pac Polymers Inc.
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Publication of WO2000039205A1 publication Critical patent/WO2000039205A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/141—Feedstock
    • Y02P20/143—Feedstock the feedstock being recycled material, e.g. plastics
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the invention resides in the chemical arts. More particularly, it relates to the reclamation of recyclable material from a physical combination of such material and plastic material.
  • the plastic material involved in this invention is poly(alkylene carbonate) material.
  • This is material selected from the group consisting of homopoly ers, and random and block copolymers, of alkylene carbonates .
  • Examples of the members of the group are given in such U.S. Patents as 3,585,168 of Inou ⁇ et al., (normally solid homopolymers), 4,763,715 of Cannarsa et al . , (normally solid random copolymers), and 4,665,136 of Santangelo et al., (normally solid block coploymers) .
  • the disclosures of these patents are incorporated by reference.
  • These homopolymers and copolymers are generically referred herein as poly(alkylene carbonates) .
  • Poly(alkylene carbonates) are thermoplastic polymers that can be made by a process in which a mixture of carbon dioxide and one or more than one alkylene oxide is reacted with a catalyst such as a zinc dicarboxylate to form a reaction mixture containing a homopolymer (in the case of one alkylene oxide) or a random copolymer (in the case of more than one alkylene oxide).
  • a catalyst such as a zinc dicarboxylate
  • a mixture of the above reaction mixture, carbon dioxide and another alkylene oxide, or more than one alkylene oxide, are reacted with or without added catalyst to form another reaction mixture, but one containing a block copolymer product.
  • One or more than one such additional reaction steps can be performed as desired.
  • the polymerization reaction conditions, and polymer recovery and work-up steps are disclosed in the above cited patents.
  • the homo- and copolymers obtained by the above process are amorphous and normally solid in that when in the form of shaped articles the articles maintain their shapes under gravity at temperatures up to at least 120°C.
  • the alkylene moiety of the monomeric units of these polymers has two-eight carbons. Larger numbers of carbons, however, are within the broader scope of the invention.
  • poly(alkylene carbonates) include poly(ethylene carbonate), a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 1.4, and the thermal decomposition temperature (TGA) of which is 220°C, and poly(propylene carbonate) , a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 0.9, and the thermal decomposition temperature (TGA) of which is 250°C.
  • poly(ethylene carbonate) a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 1.4, and the thermal decomposition temperature (TGA) of which is 220°C
  • poly(propylene carbonate) a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 0.9, and the thermal decomposition temperature (TGA) of which is 250°C.
  • the U.S. Patent 4,142,021 of Dixon et al . discloses oxygen barrier laminated sheets, useful for packaging food, and comprising a base layer and an adhesive barrier layer bonded to the base layer.
  • the adhesive barrier layer is a poly(alkylene carbonate) which is normally solid at 70°F (21°C).
  • the base layer is polymeric, metallic or fibrous.
  • Examples of a polymeric base layer disclosed in the patent include films of such polymers as ionomers; poly(vinyl chloride); polyethylene; polypropylene; ethylene-propylene copolymers; polystyrene; and polya ides such as polycaprolactam, polyhexamethyl ⁇ ne adipamid ⁇ , copolymer of adipamide and hexamethylene sebacamide, and copolymer of adipamid ⁇ and caprolactam; polyester; aromatic polycarbonates; and the lik ⁇ .
  • Di ⁇ clos ⁇ d as examples of a fibrous base layer are paper substrates such as uncoated wrapping paper.
  • the paper discloses an optional top layer, examples of materials of components of which include not only some of th ⁇ abov ⁇ polymers, but also poly(vinylidine chloride), poly(vinyl alcohol), polysulfone and phenylen ⁇ oxide polymers. While not mentioned in the patent, it is inevitable that the commercial manufactur ⁇ of such laminat ⁇ s and of articles from them will result in scrap. Of course, when the laminates and articles thereof have serv ⁇ d their purpose, they becom ⁇ wast ⁇ .
  • the sintering step is carried out at a temperatur ⁇ at which the poly(alkylene carbonate) binder thermally decomposes to the corresponding alkylene carbonate which vaporizes, or the binder burns (when the step is done in air) to form carbon dioxide and water vapor.
  • a temperatur ⁇ at which the poly(alkylene carbonate) binder thermally decomposes to the corresponding alkylene carbonate which vaporizes, or the binder burns (when the step is done in air) to form carbon dioxide and water vapor.
  • a problem to which this invention provides a solution is th ⁇ recovery or reclamation of recyclable material from the scrap that is inevitabl ⁇ in th ⁇ comm ⁇ rcial manufactur ⁇ of th ⁇ above laminat ⁇ s [which included ⁇ poly(alkylene carbonate) coated paper and th ⁇ like], and of c ⁇ ramic articles by the above described procedure up to the sintering step, and from the waste resulting when such articles and th ⁇ like have served their purpos ⁇ .
  • a probl ⁇ to which this invention provides a solution is the recovery or reclamation of normally solid recyclable material such as , for example, cellulose fiber, polymers, ceramic powders, metal powders, and th ⁇ lik ⁇ , from physical combinations of such with poly(alkyl ⁇ ne carbonates).
  • the invention comprises a process for reclaimimg normally solid r ⁇ cyclable material from a physical combination consisting essentially of such material and normally solid poly(alkylene carbonate) material.
  • the process broadly comprises treating the physical combination to degrade the solid poly(alkylen ⁇ carbonate) material to a liquid without substantially degrading or substantially oxidizing the solid r ⁇ cyclable material, and separating solid recyclable material from the liquid.
  • hydroxy material selected from the group consisting of water and normally liquid, hydroxy aliphatic organic compounds;
  • the physical combination here involved includes (1) a simple mixture of normally solid particles, in fibrous or other form, of recyclable material and of normally solid poly(alkylene carbonate) material; (2) normally solid particles, in fibrous or other form, of recyclable material coated with normally solid poly(alkylene carbonate) material; and (3) normally solid particles, in fibrous or other form, of recyclable mat ⁇ rial in a matrix of normally poly(alkyl ⁇ n ⁇ carbonat ⁇ ) material.
  • the combination in the pref ⁇ rred practice of the process, is reduced to a divided, that is, a particulate, condition. This condition is achieved by conventional ways and means, which include chopping, grinding, and the like.
  • the extent of reduction to a particulate condition can be from coarsly divided to finely divid ⁇ d, but in gen ⁇ ral it is based on practical considerations such as the intend ⁇ d us ⁇ of th ⁇ r ⁇ claimed material, economics of th ⁇ proc ⁇ ss, and th ⁇ lik ⁇ .
  • the divided condition is achieved with a minimum of reduction of the fiber.
  • the process gen ⁇ rally is limit ⁇ d to a physical combination in which th ⁇ th ⁇ rmal decomposition temperature of the recyclable material is substantially above 100°C. If the process is to be carried out without the exclusion of air, the recyclabl ⁇ mat ⁇ rial must be such that the temp ⁇ rature at which relatively rapid, air oxidation begins also must be substantially above 100°C.
  • conc ⁇ pts of this invention include in th ⁇ admixing step catalyst material at a catalytically effectiv ⁇ conc ⁇ ntration, that caus ⁇ s substantial r ⁇ duction of th ⁇ minimum temperature at which occurs significant degradation of the poly( alkylene carbonate) material, substantial acceleration of the degradation of the poly(alkylene carbonate) material, or both such reduction and accel ⁇ ration.
  • Th ⁇ catalyst mat ⁇ rial comprises one or mor ⁇ than on ⁇ catalyst.
  • the catalyst or catalysts include transterification catalysts and hydrolysis catalysts, such as tributyltin dilaurate and the like.
  • An example of a catalytically effective concentration is 100 parts by weight per million parts by weight of the poly(alkylene carbonate) material in th ⁇ physical combination to b ⁇ treated.
  • hydroxy mat ⁇ rial compri ⁇ s one or more than one of the members of the recited group.
  • Normally liquid, hydroxy aliphatic compounds are hydroxy aliphatic compounds that at 20-25°C are liquid under atmosph ⁇ ric pr ⁇ ssure.
  • Pref ⁇ rr ⁇ d normally liquid, hydroxy aliphatic compounds ar ⁇ mono- and polyhydric alcohols.
  • alkanols having one-six carbons examples of which are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl and tert-butyl alcohols, the pentyl alcohols, th ⁇ alicyclic alcohols including cyclohexanol and the like, and such polyhydric aliphatic alcohols as glycerol and the lik ⁇ .
  • Th ⁇ quantity of hydroxy mat ⁇ rial ad ix ⁇ d with th ⁇ physical combination should be about 1-30%, preferably 3-10%, by w ⁇ ight of th ⁇ physical combination to b ⁇ tr ⁇ ated.
  • t ⁇ mp ⁇ ratur ⁇ rang ⁇ in which th ⁇ mixtur ⁇ of th ⁇ physical combination and the hydroxy mat ⁇ rial is treated is as set forth above.
  • the r ⁇ cyclabl ⁇ mat ⁇ rial consists ⁇ ssentially of cellulose fiber
  • the hydroxy material comprises water
  • no catalyst material is added or otherwise part of the initial mixture
  • oxygen is not excluded in the practice of the process steps
  • a pref ⁇ rr ⁇ d tr ⁇ atm ⁇ nt t ⁇ mp ⁇ rature range is 120-200°C
  • a mor ⁇ pr ⁇ f ⁇ rred rang ⁇ is 150-180°C.
  • At th ⁇ s ⁇ t ⁇ p ⁇ ratur ⁇ th ⁇ r ⁇ is a good balance between the rate of oxidation of the cellulose, which should be as low as practicable, and the rate at which the poly( alkylene carbonate) material becomes liquid, which should b ⁇ as high as practicable.
  • Separation of the recyclable material from the reaction mixture i ⁇ done aft ⁇ r substantially all of th ⁇ poly(alkyl ⁇ ne carbonate) material has become material that is liquid in the separation temperatur ⁇ range.
  • the separation i ⁇ carried out while the temperatur ⁇ of the reaction mixture i ⁇ still high enough to maintain in th ⁇ liquid state th ⁇ alkylene carbonate( s) , low ⁇ r molecular weight poly( alkylene carbonate) material, or both, formed in th ⁇ treatment step.
  • Such t ⁇ mperature generally is in rang ⁇ from about 30 to about 100°C.
  • S ⁇ paration is don ⁇ by conv ⁇ ntional ways and means, for exampl ⁇ , distillation, filtration, and th ⁇ lik ⁇ .
  • a feature of advantage of the process of this invention is that useful products of degradation of th ⁇ ⁇ tarting poly( alkylene carbonate) material al ⁇ o can be obtained.
  • Separation of the crystallized alkylene carbonate material and the liquid hydroxy material is carried out by conventional ways and means for separating ⁇ olid ⁇ and liquid ⁇ , which include filtration, evaporation by the application of heat, vacuum, or both, and the like.
  • Alkyl ⁇ n ⁇ carbonat ⁇ s ar ⁇ useful as plasticizers for poly( alkylene carbonates), and as monomers for th ⁇ production of poly( alkyl ⁇ n ⁇ carbonates).
  • the poly(alkylene carbonate) material i ⁇ degraded to lower molecular weight poly(alkylene carbonate) material.
  • the polymer chains in such mat ⁇ rial ar ⁇ hydroxy t ⁇ r inated.
  • the monomeric units of th ⁇ polymers that make up the lower molecular weight material corr ⁇ spond to th ⁇ monom ⁇ ric units of th ⁇ poly ⁇ rs that mak ⁇ up the poly( alkylene carbonate) material befor ⁇ b ⁇ ing tr ⁇ ated according to th ⁇ treatm ⁇ nt ⁇ t ⁇ p. How ⁇ ver, there are not as many such units in the polymer chains of the degraded polymer mat ⁇ rial.
  • th ⁇ tr ⁇ atm ⁇ nt ⁇ tep is carried out to the ⁇ xt ⁇ nt the poly( alkylene carbonate) material becom ⁇ liquid at l ⁇ a ⁇ t in th ⁇ separation temperature range. If the treatm ⁇ nt st ⁇ p is carri ⁇ d out just to the point the mat ⁇ rial becomes liquid, the resulting degraded polymer material gen ⁇ rally is solid at 20-25°C. On th ⁇ oth ⁇ r hand, the treatment step can be continued to where the degraded polymer material even at 20-25°C is a viscous liquid.
  • the degrad ⁇ d polym ⁇ r raat ⁇ rial when it is cool ⁇ d to 20-25°C, it can be separated from residual hydroxy material. Separation of the degraded polymer material and the liquid hydroxy material i ⁇ carried out by conventional ways and means, which include filtration, decantation, centrifugation, evaporation by the application of heat, vacuum, or both, and the like.
  • the degraded polymer product thus obtained has not only a lower molecular weight poly(alkylen ⁇ carbonat ⁇ ) mat ⁇ rial content, but also an alkylene carbonate material content, the concentration of which is dependent on the length of time the degraded polymer material is subjected to the above elevated temp ⁇ ratur ⁇ and pr ⁇ sur ⁇ condition ⁇ .
  • This alkylene carbonate content can be of advantage as a plasticizer of the lower molecular weight poly(alkylen ⁇ carbonate) mat ⁇ rial if it is normally ⁇ olid, and the product alone or in phy ⁇ ical combination with other material, i ⁇ extruded, inject ⁇ d mold ⁇ d, or th ⁇ lik ⁇ .
  • the alkylen ⁇ carbonate content of the degrad ⁇ d polym ⁇ r product is not want ⁇ d, or its conc ⁇ ntration must be reduced to an acceptable level
  • the alkylene carbonate content in whole or in part is separated from the lower molecular weight poly(alkylene carbonate) material by extraction with a solvent (for example, methanol) for th ⁇ alkylen ⁇ carbonat ⁇ content.
  • a solvent for example, methanol
  • the lower molecular weight poly( alkylen ⁇ carbonate) material thus obtained has utility a ⁇ a sacrificial binder in the manufacture of articles from ceramic, metallic and glass powders in those instance ⁇ wher ⁇ it i ⁇ de ⁇ ired or requir ⁇ d that th ⁇ binder thermally decompose or burn at a temperatur ⁇ substantially lower than th ⁇ thermal decomposition or burning temperature of the higher molecular weight poly(alkylen ⁇ carbonate) material. Because the polymer chains of the lower molecular weight poly(alkylene carbonate) material are hydroxy terminated, ⁇ uch material al ⁇ o ha ⁇ utility as isocyanate r ⁇ active material in the production of polyurethan ⁇ and articles ther ⁇ from.
  • the hydroxyl moieties ther ⁇ of can b ⁇ reacted with an alkenylacyl halide (for ⁇ xampl ⁇ , acryloyl chlorid ⁇ ) or an alkenyl carboxylic acid (for example, methacrylic acid) to form functional groups that, with th ⁇ aid of a conventional chemical initiator, can be cros ⁇ -linked with molecular energizing radiation such a ⁇ light.
  • Th ⁇ ⁇ xtent of poly( alkylene carbonat ⁇ ) material degradation i ⁇ time d ⁇ pendent at any given treatm ⁇ nt t ⁇ mp ⁇ rature.
  • the high ⁇ r th ⁇ mol ⁇ cular wight of a poly( alkylene carbonate) the longer i ⁇ the tim ⁇ to degrade it at a given temperatur ⁇ .
  • Al ⁇ o, th ⁇ high ⁇ r th ⁇ number of carbon atom ⁇ in the alkylen ⁇ carbonat ⁇ mono ⁇ ric units of a poly( alkylene carbonate) the higher the temperatur ⁇ ⁇ hould b ⁇ for its degradation.

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Abstract

Disclosed is the recovery of normally solid recyclable material from a physical combination of it and normally solid poly(alkylene carbonate) by (1) subjecting a mixture of the combination and normally liquid hydroxy material to heat and pressure until the poly(alkylene carbonate) degrades to a liquid, and (2) separating the recyclable material from the liquid portion of the resulting mixture. Separation of lower molecular weight poly(alkylene carbonate), alkylene carbonate, or a mixture thereof from the liquid portion is disclosed also.

Description

DESCRIPTION
TITLE OF THE INVENTION
RECOVERY OF RECYCLABLE MATERIAL FROM A PHYSICAL COMBINATION OF IT AND NORMALLY SOLID POLY(ALKYLENE CARBONATE) MATERIAL
CROSS-REFERENCE TO RELATED APPLICATIONS
Provisional, U.S. Patent Application, Serial No. 60/114,236, filed December 30, 1998, the priority of which is claimed.
FIELD OF THE INVENTION
The invention resides in the chemical arts. More particularly, it relates to the reclamation of recyclable material from a physical combination of such material and plastic material.
BACKGROUND OF INVENTION
The plastic material involved in this invention is poly(alkylene carbonate) material. This is material selected from the group consisting of homopoly ers, and random and block copolymers, of alkylene carbonates . Examples of the members of the group are given in such U.S. Patents as 3,585,168 of Inouε et al., (normally solid homopolymers), 4,763,715 of Cannarsa et al . , (normally solid random copolymers), and 4,665,136 of Santangelo et al., (normally solid block coploymers) . The disclosures of these patents are incorporated by reference. These homopolymers and copolymers are generically referred herein as poly(alkylene carbonates) .
Poly(alkylene carbonates) are thermoplastic polymers that can be made by a process in which a mixture of carbon dioxide and one or more than one alkylene oxide is reacted with a catalyst such as a zinc dicarboxylate to form a reaction mixture containing a homopolymer (in the case of one alkylene oxide) or a random copolymer (in the case of more than one alkylene oxide). See, for example, the U.S. Patent 4,981,948 of Kawachi et al . , and the U.S. Patent 5,026,676 of Motika et al . , the disclosures of which patents are incorporated herein by reference. In the case of a block copolymer, a mixture of the above reaction mixture, carbon dioxide and another alkylene oxide, or more than one alkylene oxide, are reacted with or without added catalyst to form another reaction mixture, but one containing a block copolymer product. One or more than one such additional reaction steps can be performed as desired. The polymerization reaction conditions, and polymer recovery and work-up steps are disclosed in the above cited patents.
The homo- and copolymers obtained by the above process are amorphous and normally solid in that when in the form of shaped articles the articles maintain their shapes under gravity at temperatures up to at least 120°C. In general, the alkylene moiety of the monomeric units of these polymers has two-eight carbons. Larger numbers of carbons, however, are within the broader scope of the invention. Commercially available poly(alkylene carbonates) include poly(ethylene carbonate), a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 1.4, and the thermal decomposition temperature (TGA) of which is 220°C, and poly(propylene carbonate) , a typical melt flow rate (ASTM 1238, g/lOmin @150°C/2.160kg) of which is 0.9, and the thermal decomposition temperature (TGA) of which is 250°C.
The U.S. Patent 4,142,021 of Dixon et al . , discloses oxygen barrier laminated sheets, useful for packaging food, and comprising a base layer and an adhesive barrier layer bonded to the base layer. The adhesive barrier layer is a poly(alkylene carbonate) which is normally solid at 70°F (21°C). The base layer is polymeric, metallic or fibrous. Examples of a polymeric base layer disclosed in the patent include films of such polymers as ionomers; poly(vinyl chloride); polyethylene; polypropylene; ethylene-propylene copolymers; polystyrene; and polya ides such as polycaprolactam, polyhexamethylεne adipamidε, copolymer of adipamide and hexamethylene sebacamide, and copolymer of adipamidε and caprolactam; polyester; aromatic polycarbonates; and the likε. Diεclosεd as examples of a fibrous base layer are paper substrates such as uncoated wrapping paper. The paper discloses an optional top layer, examples of materials of components of which include not only some of thε abovε polymers, but also poly(vinylidine chloride), poly(vinyl alcohol), polysulfone and phenylenε oxide polymers. While not mentioned in the patent, it is inevitable that the commercial manufacturε of such laminatεs and of articles from them will result in scrap. Of course, when the laminates and articles thereof have servεd their purpose, they becomε wastε.
Other publications such as the U.S. Patents 4,814,370 and 4,882,110 of Kramer et al . , and the U.S. Patent 5,089, 070 of McAndrew, disclose, in the context of the manufacture of ceramic articles, ceramic powders coated with or in melt blend with poly( alkylene carbonates) such as poly(ethylene carbonate) and poly(propylenε carbonatε) . In such manufacture thε poly(alkylene carbonate) functions as a binder of the ceramic powder until the shaped "green" articles are sintered to fuse the ceramic particles. The sintering step is carried out at a temperaturε at which the poly(alkylene carbonate) binder thermally decomposes to the corresponding alkylene carbonate which vaporizes, or the binder burns (when the step is done in air) to form carbon dioxide and water vapor. Again, while not specifically mentioned in thesε patents, it is inevitable that under commercial conditions the manufacturing procedure up to the sintering step will result in economically significant quantities of "scrap" ceramic powder in physical combination with poly(alkylene carbonate) .
A problem to which this invention provides a solution is thε recovery or reclamation of recyclable material from the scrap that is inevitablε in thε commεrcial manufacturε of thε above laminatεs [which includε poly(alkylene carbonate) coated paper and thε like], and of cεramic articles by the above described procedure up to the sintering step, and from the waste resulting when such articles and thε like have served their purposε. More broadly, a problε to which this invention provides a solution is the recovery or reclamation of normally solid recyclable material such as , for example, cellulose fiber, polymers, ceramic powders, metal powders, and thε likε, from physical combinations of such with poly(alkylεne carbonates).
SUMMARY OF THE INVENTION
In summary, the invention comprises a process for reclaimimg normally solid rεcyclable material from a physical combination consisting essentially of such material and normally solid poly(alkylene carbonate) material.
In general the process broadly comprises treating the physical combination to degrade the solid poly(alkylenε carbonate) material to a liquid without substantially degrading or substantially oxidizing the solid rεcyclable material, and separating solid recyclable material from the liquid.
A more specific embodiment of the process comprises:
(a) admixing hydroxy material with the physical combination, the hydroxy material being selected from the group consisting of water and normally liquid, hydroxy aliphatic organic compounds;
(b) treating thε resulting mixture by (i) establishing it in a treatment temperature range generally of about 100-220°C, but with the maxi un temperature therεof being less than the thermal decomposition temperaturε of thε recyclable material, and, if air is not excluded, the temperature at which relatively rapid air oxidation of said recyclablε matεrial begins, and under pressurε sufficient to maintain the hydroxy material in the liquid state; and (ii) maintaining thε mixturε undεr thεsε conditions until substantially all of thε poly( alkylene carbonate) material has become material that is liquid in the following separation temperature range; and (c) separating in a separation temperature range of about 30-100°C said recyclable material from the liquid portion of the rεsulting rεaction mixturε.
DETAILED DESCRIPTION OF THE INVENTION
The physical combination here involved includes (1) a simple mixture of normally solid particles, in fibrous or other form, of recyclable material and of normally solid poly(alkylene carbonate) material; (2) normally solid particles, in fibrous or other form, of recyclable material coated with normally solid poly(alkylene carbonate) material; and (3) normally solid particles, in fibrous or other form, of recyclable matεrial in a matrix of normally poly(alkylεnε carbonatε) material. In the latter situation, in the prefεrred practice of the process, the combination, if not already done, is reduced to a divided, that is, a particulate, condition. This condition is achieved by conventional ways and means, which include chopping, grinding, and the like. The extent of reduction to a particulate condition can be from coarsly divided to finely dividεd, but in genεral it is based on practical considerations such as the intendεd usε of thε rεclaimed material, economics of thε procεss, and thε likε. For example, in the case of fibrous recyclable material, and depεnding on thε intεnded use of such material after being reclaimed, the divided condition is achieved with a minimum of reduction of the fiber.
The process genεrally is limitεd to a physical combination in which thε thεrmal decomposition temperature of the recyclable material is substantially above 100°C. If the process is to be carried out without the exclusion of air, the recyclablε matεrial must be such that the tempεrature at which relatively rapid, air oxidation begins also must be substantially above 100°C.
It is within the concεpts of this invention to include in thε admixing step catalyst material at a catalytically effectivε concεntration, that causεs substantial rεduction of thε minimum temperature at which occurs significant degradation of the poly( alkylene carbonate) material, substantial acceleration of the degradation of the poly(alkylene carbonate) material, or both such reduction and accelεration. Thε catalyst matεrial comprises one or morε than onε catalyst. Examples of the catalyst or catalysts include transterification catalysts and hydrolysis catalysts, such as tributyltin dilaurate and the like. An example of a catalytically effective concentration is 100 parts by weight per million parts by weight of the poly(alkylene carbonate) material in thε physical combination to bε treated.
The hydroxy matεrial compriεεs one or more than one of the members of the recited group. Normally liquid, hydroxy aliphatic compounds are hydroxy aliphatic compounds that at 20-25°C are liquid under atmosphεric prεssure. Prefεrrεd normally liquid, hydroxy aliphatic compounds arε mono- and polyhydric alcohols. They include alkanols having one-six carbons, examples of which are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl and tert-butyl alcohols, the pentyl alcohols, thε alicyclic alcohols including cyclohexanol and the like, and such polyhydric aliphatic alcohols as glycerol and the likε.
Thε quantity of hydroxy matεrial ad ixεd with thε physical combination should be about 1-30%, preferably 3-10%, by wεight of thε physical combination to bε trεated.
In general the tεmpεraturε rangε in which thε mixturε of thε physical combination and the hydroxy matεrial is treated is as set forth above. However, when the rεcyclablε matεrial consists εssentially of cellulose fiber, the hydroxy material comprises water, no catalyst material is added or otherwise part of the initial mixture, and oxygen is not excluded in the practice of the process steps, a prefεrrεd trεatmεnt tεmpεrature range is 120-200°C, while a morε prεfεrred rangε is 150-180°C. At thεsε tε pεraturεε thεrε is a good balance between the rate of oxidation of the cellulose, which should be as low as practicable, and the rate at which the poly( alkylene carbonate) material becomes liquid, which should bε as high as practicable.
The pressure under which the initial mixture of hydroxy material and the physical combination, and thε rεεulting rεaction mixturε, arε established and maintained during the treating stεp is dεpεndent on thε tεmperature or te pεratureε at which the initial and resulting mixtures are established and maintained. In the above specified general tεmpεrature range, a prεssure of about 20-200 pεi (about 0.1-1.4 MPa), preferably 50-150 psi (about 0.3-1 MPa), usually is adequatε.
Separation of the recyclable material from the reaction mixture iε done aftεr substantially all of thε poly(alkylεne carbonate) material has become material that is liquid in the separation temperaturε range. The separation iε carried out while the temperaturε of the reaction mixture iε still high enough to maintain in thε liquid state thε alkylene carbonate( s) , lowεr molecular weight poly( alkylene carbonate) material, or both, formed in thε treatment step. Such tεmperature generally is in rangε from about 30 to about 100°C. Sεparation is donε by convεntional ways and means, for examplε, distillation, filtration, and thε likε.
A feature of advantage of the process of this invention is that useful products of degradation of thε εtarting poly( alkylene carbonate) material alεo can be obtained.
Thus, in one embodi εnt of thε procεss thε poly( alkylene carbonate) material is degraded in the treat εnt stεp all the way to alkylenε carbonate material composed of alkylene carbonate(s) corresponding to the monomeric unit(s) of thε polymers that make up the starting poly( alkylene carbonate) material. This alkylene carbonate material, liquid when recyclable material is separated from the liquid portion of thε rεaction mixturε, will crystallize when cooled to 20-25°C. Separation of the crystallized alkylene carbonate material and the liquid hydroxy material is carried out by conventional ways and means for separating εolidε and liquidε, which include filtration, evaporation by the application of heat, vacuum, or both, and the like. Alkylεnε carbonatεs arε useful as plasticizers for poly( alkylene carbonates), and as monomers for thε production of poly( alkylεnε carbonates).
In the treatmεnt step of another embodiment of the process the poly(alkylene carbonate) material iε degraded to lower molecular weight poly(alkylene carbonate) material. The polymer chains in such matεrial arε hydroxy tεr inated. The monomeric units of thε polymers that make up the lower molecular weight material corrεspond to thε monomεric units of thε poly εrs that makε up the poly( alkylene carbonate) material beforε bεing trεated according to thε treatmεnt εtεp. Howεver, there are not as many such units in the polymer chains of the degraded polymer matεrial. Thε wεight avεragε molecular weight of the alkylenε carbonatε polymer or polymers of which the lower molecular weight poly( alkylene carbonate) material iε composed iε about 1000-50,000.
Aε above indicated, thε trεatmεnt εtep is carried out to the εxtεnt the poly( alkylene carbonate) material becomεε liquid at lεaεt in thε separation temperature range. If the treatmεnt stεp is carriεd out just to the point the matεrial becomes liquid, the resulting degraded polymer material genεrally is solid at 20-25°C. On thε othεr hand, the treatment step can be continued to where the degraded polymer material even at 20-25°C is a viscous liquid. In eithεr caεε, when the degradεd polymεr raatεrial is coolεd to 20-25°C, it can be separated from residual hydroxy material. Separation of the degraded polymer material and the liquid hydroxy material iε carried out by conventional ways and means, which include filtration, decantation, centrifugation, evaporation by the application of heat, vacuum, or both, and the like. The degraded polymer product thus obtained has not only a lower molecular weight poly(alkylenε carbonatε) matεrial content, but also an alkylene carbonate material content, the concentration of which is dependent on the length of time the degraded polymer material is subjected to the above elevated tempεraturε and prεεsurε conditionε. This alkylene carbonate content can be of advantage as a plasticizer of the lower molecular weight poly(alkylenε carbonate) matεrial if it is normally εolid, and the product alone or in phyεical combination with other material, iε extruded, injectεd moldεd, or thε likε. However, when the alkylenε carbonate content of the degradεd polymεr product is not wantεd, or its concεntration must be reduced to an acceptable level, the alkylene carbonate content in whole or in part is separated from the lower molecular weight poly(alkylene carbonate) material by extraction with a solvent (for example, methanol) for thε alkylenε carbonatε content.
The lower molecular weight poly( alkylenε carbonate) material thus obtained has utility aε a sacrificial binder in the manufacture of articles from ceramic, metallic and glass powders in those instanceε wherε it iε deεired or requirεd that thε binder thermally decompose or burn at a temperaturε substantially lower than thε thermal decomposition or burning temperature of the higher molecular weight poly(alkylenε carbonate) material. Because the polymer chains of the lower molecular weight poly(alkylene carbonate) material are hydroxy terminated, εuch material alεo haε utility as isocyanate rεactive material in the production of polyurethanεε and articles therεfrom. In addition, it has utility in the photolithographic arts. For example, the hydroxyl moieties therεof can bε reacted with an alkenylacyl halide (for εxamplε, acryloyl chloridε) or an alkenyl carboxylic acid (for example, methacrylic acid) to form functional groups that, with thε aid of a conventional chemical initiator, can be crosε-linked with molecular energizing radiation such aε light. Thε thuε functionalized, degraded material iε uεeful as a negative resiεt in photolithography.
Thε εxtent of poly( alkylene carbonatε) material degradation iε time dεpendent at any given treatmεnt tεmpεrature. In general, the highεr thε molεcular wight of a poly( alkylene carbonate) the longer iε the timε to degrade it at a given temperaturε. Alεo, thε highεr thε number of carbon atomε in the alkylenε carbonatε mono εric units of a poly( alkylene carbonate) the higher the temperaturε εhould bε for its degradation.
On the basis of prεli inary work with poly(εthylεnε carbonatε), ("PEC"), the weight average molecular weight of which was 87,000, and poly(propylene carbonate), ("PPC"), the weight averagε molecular weight of which waε 195,000, the following temperaturεs and rεaction times are reco mεnded for physical combinations of celluloεε fiber and the below idεntified poly(alkylene carbonate), ("PAC"):
Hydroxy % By Wt Temp Reaction Dεεirεd Product
PAC Material of PAC °C Timε (min) Of Degradation
PEC Water 30 170 30 EC
PEC Water 30 170 45 Low MW PEC
PEC Glycerol 8.9 170 40 EC
PEC Glycεrol 8.9 170 20 Low MW PEC
PPC Watεr 15 170 70 PC
PPC Watεr 15 170 60 LOW MW PPC
PPC Glycεrol 10 170 120 Low MW PPC
PPC Watεr 15 155 180 PC
In the above table, "wt" mεanε wεight, "tεmp" mεans tempεraturε, "min" mεans minutes, "MW" mεans molεcular weight, "EC" mεans εthylεnε carbonatε, and "PC" mεans propylεne carbonatε.
Basεd on preliminary work with a normally εolid random copolymer of propylene carbonatε and cyclohexenε carbonatε, thε contεnt of propylene carbonatε unitε being 30 mol%, the content of cyclohexene carbonatε unitε being 70 mol%, and the weight average molecular weight of which waε 211,000, it appearε that the trεatmεnt tempεraturε needεd to cauεε thε copolymεr to dεgradε to liquid is too high when (a) the physical combination compriseε the copolymεr and celluloεe fiber, (b) cellulose fiber is to be recovεred without substantial oxidation or degradation, and (c) the hydroxy matεrial conεiεts of water. However, for phyεical combinationε of the copolymer with other kinds of rεcyclable material, that arε substantially unaffεctεd by thε trεatmεnt tεmpεraturε of 190°C for a rεaction timε of 6 hours, these reaction conditions and 15 weight % of water as the hydroxy material are recommεndεd for thε practice of the procesε of thiε invention to reclaim these kinds of recyclablε material, and to obtain lower molecular weight copolymer. To dεterminε thε optimum time to obtain a deεired lowεr molecular weight copolymer matεrial, it iε rεcommεndεd that a trial run bε madε at 190°C with a εamplε of thε rεaction mixturε bεing periodically withdrawn for analysis of the copolymer contεnt of thε liquid portion thereof. The process of the invention can be practiced in batch mode or in continuous mode. In eithεr modε, convεntional equipment appropriate for the modε iε εmployed. However, in eithεr mode the preferred practice includes carrying out the admixing and trεatment stepε with good, conεtant mixing action.
Othεr features, e bodimentε and advantageε of the invention will become readily apparent to thoεe in the εxεrcisε of ordinary skill in thε art aftεr rεading the foregoing disclosures. Such embodiments are within the spirit and scope of the invention as disclosed.
The expreεεion "conεiεting εεεεntially of" as usεd hεrein excludεε an unrεcitεd εubεtancε at a concεntration sufficient to εubεtantially adversεly affεct thε εεεεntial propεrtiεε and characteristics of the composition of matter being definεd, whilε pεrmitting thε prεsence of one or more than one unrεcitεd substancε at a concentration or concentrations insufficient to subεtantially adverεεly affεct said εεεential propertieε and charcteriεticε .

Claims

A proceεε for reclaiming normally εolid rεcyclablε matεrial from a physical combination consisting εsεεntially of εuch matεrial and normally εolid poly( alkylene carbonate) material, which procεεε compriεεε trεating εaid phyεical combination to dεgradε thε poly( alkylεnε carbonatε) material to a liquid without εubεtantially dεgrading or subεtantially oxidizing thε εolid rεcyclablε matεrial, and separating solid recyclable material from the liquid.
A process for reclaiming normally solid recyclablε matεrial from a physical combination consiεting eεεentially of εuch material and normally εolid poly( alkylene carbonate) material, εaid recyclable matεrial bεing charatεrizεd in that itε thεrmal dεcomposition tεmpεraturε and, if thε procesε iε carried out without the excluεion of air, the temperature at which relatively rapid oxidation thereof begins, must be substantially above 100°c, which process compriseε :
(a) admixing hydroxy material with the phyεical combination, the hydroxy material being sεlεcted from the group consisting of water and hydroxy aliphatic organic compounds that are normally liquid;
(b) treating the resulting mixture by (i) establishing it in a treatment temperaturε rangε of about 100-220°C, but with thε maximum tempεraturε bεing lεss than εaid thermal decompoεition tempεraturε and, if air iε not εxcluded, said temperature at which relatively rapid oxidation begins, and under presεure sufficient to maintain the hydroxy material in the liquid εtatε; and (ii) maintaining thε mixture under theεε conditionε until εubstantially all of the poly( alkylene carbonate) material has dεgraded to degraded poly(alkylene carbonate) matεrial that is liquid in thε following separation temperature range; and (c) separating in a separation tεmpεraturε range of about 30-100°C rεcyclable material from thε liquid portion of the resulting reaction mixture.
3. A process according to claim 2 in which thε phyεical combination iε in particulate condition.
4. A proceεε according to claim 2 in which thε quantity of hydroxy matεrial admixed with the physical combination is about 1-30% by weight of the physical combination.
5. A procesε according to claim 4 in which said quantity of hydroxy material iε about 3-10% by weight of the physical combination.
6. A procesε according to claim 2 in which the normally εolid poly( alkylenε carbonatε) material consistε eεsεntially of normally solid poly(ethylene carbonate) or normally εolid poly(propylene carbonatε) .
7. A procεss according to claim 6 in which the recyclable material conεiεtε εsεεntially of cεlluloεe fiber, and the hydroxy material consiεtε esεεntially of water or glycerol.
8. A proceεε according to claim 7 in which the treatment temperature range is 120-200°C.
9. A proceεε according to claim 8 in which the treatment temperature range iε 150-180°C.
10. A proceεε according to claim 2 in which degradεd poly(alkylene carbonate) material iε εeparated from εaid liquid portion of the reεulting rεaction mixture.
11. A proceεε according to claim 2 in which εaid liquid portion of the reεulting reaction mixturε iε coolεd to 20-25°C to thεreby εolidify εaid degraded poly( alkylene carbonatε) matεrial, and the εolidified degraded poly( alkylene carbonate) material iε separatεd from the remaindεr of εaid liquid portion.
12. A procεεε according to claim 11 in which εaid εolidifiεd degraded poly( alkylene carbonate) material consists esεentially of lowεr molεcular wεight poly( alkylεnε carbonate) material.
13. A proceεs according to claim 11 in which εaid εolidifiεd dεgradεd poly( alkylene carbonate) material conεiεts essentially of alkylene carbonate matεrial.
PCT/US1999/031132 1998-12-30 1999-12-29 Recovery of recyclable material from a physical combination of it and normally solid poly(alkylene carbonate) material WO2000039205A1 (en)

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US11423698P 1998-12-30 1998-12-30
US60/114,236 1998-12-30

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WO2019207260A1 (en) 2018-04-27 2019-10-31 Arkema France Method for recycling thermoplastic by short depolymerisation

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US4051212A (en) * 1974-09-04 1977-09-27 Bayer Aktiengesellschaft Process for the continuous degradation of plastics
US4605762A (en) * 1982-04-23 1986-08-12 Celanese Mexicana S.A. Depolymerization of condensation polymers
US4763715A (en) * 1987-12-14 1988-08-16 Arco Chemical Company Process for preparing polycarbonate terpolymer foam suitable for lost foam casting
US5391802A (en) * 1992-06-22 1995-02-21 Bayer Aktiengesellschaft Process for cleaving polycarbonates into bisphenols and diaryl carbonates

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Publication number Priority date Publication date Assignee Title
US4051212A (en) * 1974-09-04 1977-09-27 Bayer Aktiengesellschaft Process for the continuous degradation of plastics
US4605762A (en) * 1982-04-23 1986-08-12 Celanese Mexicana S.A. Depolymerization of condensation polymers
US4763715A (en) * 1987-12-14 1988-08-16 Arco Chemical Company Process for preparing polycarbonate terpolymer foam suitable for lost foam casting
US5391802A (en) * 1992-06-22 1995-02-21 Bayer Aktiengesellschaft Process for cleaving polycarbonates into bisphenols and diaryl carbonates

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2019207260A1 (en) 2018-04-27 2019-10-31 Arkema France Method for recycling thermoplastic by short depolymerisation
FR3080622A1 (en) * 2018-04-27 2019-11-01 Arkema France PROCESS FOR RECYCLING THERMOPLASTIC BY SHORT DEPOLYMERIZATION

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