WO2000039172A1 - Process for obtaining lower molecular weight poly(alkylene carbonate) from higher molecular weight poly(alkylene carbonate) - Google Patents
Process for obtaining lower molecular weight poly(alkylene carbonate) from higher molecular weight poly(alkylene carbonate) Download PDFInfo
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- WO2000039172A1 WO2000039172A1 PCT/US1999/031130 US9931130W WO0039172A1 WO 2000039172 A1 WO2000039172 A1 WO 2000039172A1 US 9931130 W US9931130 W US 9931130W WO 0039172 A1 WO0039172 A1 WO 0039172A1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G64/00—Macromolecular compounds obtained by reactions forming a carbonic ester link in the main chain of the macromolecule
- C08G64/42—Chemical after-treatment
Definitions
- the invention resides in the chemical arts. It relates to the art of synthetic resins, and more particularly to poly( alkylene carbonates) .
- Poly(alkylene carbonates) are thermoplastic homopoly ers and copolymer ⁇ of alkylene carbonates.
- the alkylene moiety of the monomeric units of these polymers has two-eight carbons .
- Embodiments of these polymers are disclosed in such U.S. Patents as 3,585,168 of Inoue 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 coploymer ⁇ ). The disclosures of these patents are incorporated by reference.
- each alkylene carbonate monomeric unit in the random and block polymers can vary, but generally is in the range of 10-90 mole % of each polymer.
- specific poly( alkylene carbonates) include poly(ethylene carbonate), poly(propylene carbonate), poly(cyclohexylene carbonate), random copolymer of ethylene carbonate and propylene carbonate, random copolymer of propylen ⁇ carbonate and cyclohexene carbonate, block copolymer of ethylene carbonate and propylene carbonate, and block copolymer of propylene carbonate and cyclohexene carbonate.
- Poly(alkylene carbonates) are made by a process which, for ease of reference, is referred to herein as the zinc catalyst process.
- 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 thus obtained are amorphous, and are normally solid, that is, shaped articles of them maintain their shapes under the force of gravity at temperatures up to at least about 120°C.
- Their weight average molecular weights generally are in the range from about 50,000 to about 800,00.
- the zinc catalyst process does not appear to be capable of making alkylene carbonate homo- and copolymer products predominate in homo- and copolymers of weight average molecular weight generally in the range from about 1,000 to about 50,000.
- poly(alkylene carbonates) is as sacrificial binders in the manufacture of articles from ceramic and metal powders. See, for example, the U.S. Patents 4,814,370 and 4,882,110 of Kramer et al . , and the U.S. Patent 5,089,070 of
- the poly( alkylene carbonate) functions as a binder of the powder until the shaped "green" articles thereof are sintered to fuse together the ceramic or metallic particles.
- the sintering step is carried out at temperatures at which the poly(alkylene carbonate) binder thermally decomposes or burns (when the step is done without the exclusion of air) .
- poly( alkylene carbonates) of lower molecular weights that is, of shorter polymer chain lengths, than poly(alkylene carbonates) of higher molecular weights, and particularly those made by the zinc catalyst process, might be more advantageous as sacrificial binders in ceramic technologies being developed.
- Poly( alkylene carbonates) of lower molecular weights tend to thermally decompose at lower temperatures and at faster rates than the higher molecular weight alkylene carbonate polymers .
- the invention hereof provides a process for obtaining a lower molecular weight poly( alkylene carbonate) from a higher molecular weight poly( alkylene carbonate).
- Specific embodiments of the process enables the production of poly(alkylene carbonates) of weight average molecular weights of about 1,000-50,000 from poly( alkylene carbonates) made by the zinc catalyst process, that is, poly( alkylene carbonates) of weight average molecular weights of about 50,000-800,000.
- the process comprises:
- hydroxy material (a) admixing hydroxy material with the higher molecular weight poly( alkylene carbonate), the hydroxy material being selected from the group consisting of water and normally liquid, hydroxy aliphatic compounds;
- the reaction mixture thus obtained consists essentially of lower molecular weight poly(alkylene carbonate). In most embodiments of the process, lower molecular weight poly(alkylene carbonate) is separated from the reaction mixture.
- the hydroxy material comprises 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 atmospheric pressure.
- Preferred normally liquid, hydroxy aliphatic compounds are 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, the h ⁇ xyl alchols the alicyclic alcohols including cyclohexanol and the like, and such polyhydric aliphatic alcohols as glycerol and the like.
- the quantity of hydroxy material admixed with the physical combination should be about 1-30%, preferably 3-10%, by weight of the higher molecular weight poly( alkylene carbonate).
- the catalyst material comprises one or more than one catalyst.
- the catalyst or catalysts include transesterification 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 higher molecular weight poly( alkylene carbonate).
- the pressure under which the initial mixture of hydroxy material and the higher molecular weight poly( alkylene carbonate), and the resulting reaction mixture, is established and maintained during the treating step is dependent on the temperature or temperatures at which the initial and resulting mixtures are established and maintained. In the above specified general temperature range, a pressure of about 20-200 psi (about 0.1-1.4 MPa) , preferably 50-150 psi (about 0.3-1 MPa) , usually is adequate .
- Th ⁇ p ⁇ riod of time the high ⁇ r mol ⁇ cular w ⁇ ight poly( alkylene carbonat ⁇ ) is subj ⁇ cted to these conditions is depend ⁇ nt on the number of carbons in the alkyl ⁇ ne moieties of, and the number of monomeric units in, the polymer chains. In general, the higher the molecular weight of a poly(alkylene carbonate) the longer is the time to degrade it at a giv ⁇ n te peratur ⁇ . Also, th ⁇ higher the number of carbon atoms in the alkylene carbonat ⁇ monomeric units of a poly(alkylene carbonate) the higher the t ⁇ mp ⁇ rature should be for its degradation.
- the range of the period of time is from about five minut ⁇ to about fifty hours.
- som ⁇ ⁇ mbodim ⁇ nts of th ⁇ proc ⁇ ss p ⁇ riods of ti ⁇ within this range are sel ⁇ ct ⁇ d to r ⁇ sult in lower molecular weight poly(alkyl ⁇ n ⁇ carbonate) that is still solid at 20-25°C.
- the p ⁇ riod of tr ⁇ atm ⁇ nt tim ⁇ is insuffici ⁇ nt to form more than a quantatively minor amount of alkylene carbonate.
- a batch mode trial run be made at a t ⁇ mperature in the treat ⁇ nt t ⁇ mperature range, and under pressur ⁇ sufficient to keep the hydroxy mat ⁇ rial in th ⁇ r ⁇ action mixture, that is, keep it liquid, and during the run periodically withdraw a sample of th ⁇ reaction mixture for analysis of the lower mol ⁇ cular weight poly( alkylene carbonate) content and alkylen ⁇ carbonat ⁇ (s) content th ⁇ r ⁇ of.
- lower mol ⁇ cular w ⁇ ight poly( alkyl ⁇ n ⁇ carbonat ⁇ ) is isolated from the reaction mixture. This can be done by cooling the reaction mixture to room te p ⁇ ratur ⁇ (20-25°C). Regardless of wheth ⁇ r th ⁇ low ⁇ r mol ⁇ cular w ⁇ ight poly( alkyl ⁇ n ⁇ carbonate) is solid or liquid at this temperature, it is not in solution in the hydroxy material. It is either a solid or a liquid immiscible with the hydroxy material. In a broad sens ⁇ , it and th ⁇ hydroxy mat ⁇ rial ar ⁇ segregated.
- Henc ⁇ after cooling the reaction mixture to the indicated temperature, lower molecular weight poly(alkylen ⁇ carbonat ⁇ ) product is separated by conventional ways and means for separating solids from liquids, or separating immiscible liquids.
- Such ways and m ⁇ ans included ⁇ filtration (wh ⁇ n th ⁇ product is solid), d ⁇ cantation, c ⁇ ntrifugation, ⁇ vaporation of hydroxy material by the application of heat, vacuum, or both, and the like.
- Th ⁇ process of the invention can b ⁇ practiced in batch mod ⁇ or in continuous mod ⁇ .
- conv ⁇ ntional equipment appropriate for the mod ⁇ is ⁇ mployed.
- the preferred practice includes carrying out the admixing and treatm ⁇ nt st ⁇ ps with good, constant mixing action.
- the degrad ⁇ d polymer product of th ⁇ proc ⁇ ss usually compris ⁇ s not only low ⁇ r molecular weight poly(alkyl ⁇ ne carbonate), but also alkyl ⁇ n ⁇ carbonat ⁇ , or alkyl ⁇ n ⁇ carbonates if the higher molecular weight poly( alkylene carbonat ⁇ ) had differ ⁇ nt alkyl ⁇ n ⁇ carbonat ⁇ monom ⁇ ric units.
- Th ⁇ conc ⁇ ntration of th ⁇ alkyl ⁇ n ⁇ carbonate(s) is dep ⁇ ndent on the length of time the polymeric material is subj ⁇ ct ⁇ d to th ⁇ abov ⁇ ⁇ l ⁇ vated temp ⁇ ratur ⁇ and pressure conditions.
- This alkylen ⁇ carbonat ⁇ (s) cont ⁇ nt can b ⁇ of advantag ⁇ as a plasticiz ⁇ r of th ⁇ low ⁇ r molecular weight poly(alkylen ⁇ carbonat ⁇ ) when it is normally solid, and the d ⁇ graded polymer product alone or with other mat ⁇ rial is extruded, injection molded or the like.
- th ⁇ alkyl ⁇ n ⁇ carbonat ⁇ (s) cont ⁇ nt in whol ⁇ or in part is s ⁇ parated from the lower molecular weight poly(alkylene carbonate) by extraction with a solvent (for example, ethanol) for the alkylene carbonate(s) content.
- a solvent for example, ethanol
- the lower molecular weight poly( alkylene carbonate) thus obtain ⁇ d has utility as a sacrificial bind ⁇ r in th ⁇ manufactur ⁇ of articl ⁇ s from c ⁇ ramic, m ⁇ tallic and glass powd ⁇ rs in those instances wher ⁇ it is d ⁇ ired or requir ⁇ d that the binder thermally decompos ⁇ or burn at a t ⁇ mp ⁇ ratur ⁇ substantially lower than the thermal decomposition or burning temp ⁇ ratur ⁇ of th ⁇ high ⁇ r mol ⁇ cular w ⁇ ight poly(alkyl ⁇ n ⁇ carbonate) .
- the hydroxyl oieti ⁇ th ⁇ r ⁇ of can b ⁇ reacted with an alkenylacyl halid ⁇ (for ⁇ xampl ⁇ , acryloyl chlorid ⁇ ) or an alk ⁇ nyl carboxylic acid (for ⁇ xampl ⁇ , m ⁇ thacrylic acid) to form functional group ⁇ that, with th ⁇ aid of a conv ⁇ ntional chemical initiator, can be cro ⁇ -linked with molecular energizing radiation ⁇ uch a ⁇ light.
- the thus functionalized, low ⁇ r mol ⁇ cular w ⁇ ight poly( alkyl ⁇ n ⁇ carbonate) is useful as a n ⁇ gativ ⁇ r ⁇ sist in photolithography.
- th ⁇ hydroxy material consisted of wat ⁇ r, th ⁇ quantity of which was 15% by w ⁇ ight of th ⁇ copolym ⁇ r, th ⁇ tr ⁇ atm ⁇ nt temp ⁇ ratur ⁇ was 190°C, and th ⁇ treatment time was 5 hours.
- Th ⁇ ⁇ xpr ⁇ s ⁇ ion excludes an unrecit ⁇ d substanc ⁇ at a conc ⁇ ntration suffici ⁇ nt to substantially adversely affect th ⁇ e ⁇ sential prop ⁇ rties and characteri ⁇ tics of th ⁇ composition of att ⁇ r b ⁇ ing defined, whil ⁇ p ⁇ rmitting th ⁇ presence of one or mor ⁇ than one unrecited substance at a concentration or conc ⁇ ntrations insuffici ⁇ nt to substantially adversely aff ⁇ ct said ⁇ ss ⁇ ntial properties and charcteristics .
Abstract
Disclosed is a process for reducing the molecular weight of a normally solid poly(alkylene carbonate). The process comprises subjecting a mixture of the normally solid poly(alkylene carbonate) and hydroxy material (which under atmospheric pressure is liquid at room temperature) to heat and enough pressure to keep the hydroxy material liquid, and doing this until substantially all of the poly(alkylene carbonate) has degraded to poly(alkylene carbonate) of the desired lower molecular weight. The hydroxy material is selected from the group consisting of water, glycerol and other normally liquid, hydroxy aliphatic compounds. Lower molecular weight poly(alkylene carbonate) product is obtained from the resulting reaction mixture by cooling the mixture to room temperature, and separating the thus segregated product from the hydroxy material portion of the mixture.
Description
DESCRIPTION
TITLE OF THE INVENTION
PROCESS FOR OBTAINING LOWER MOLECULAR WEIGHT
POLY (ALKYLENE CAREONATE ) FROM HIGHER MOLECULAR WEIGHT
POLY(ALKYLENE CAREONATE )
CROSS-REFERENCE TO RELATED APPLICATIONS
Provisional, U.S. Patent Application, Serial No. 60/114,238, filed December 30, 1998, the priority of which is claimed.
FIELD OF THE INVENTION
The invention resides in the chemical arts. It relates to the art of synthetic resins, and more particularly to poly( alkylene carbonates) .
BACKGROUND OF INVENTION
Poly(alkylene carbonates) are thermoplastic homopoly ers and copolymerε of alkylene carbonates. In general, the alkylene moiety of the monomeric units of these polymers has two-eight carbons . Embodiments of these polymers are disclosed in such U.S. Patents as 3,585,168 of Inoue 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 coploymerε). The disclosures of these patents are incorporated by reference. The content of each alkylene carbonate monomeric unit in the random and block polymers can vary, but generally is in the range of 10-90 mole % of each polymer. Examples of specific poly( alkylene carbonates) include poly(ethylene carbonate), poly(propylene carbonate), poly(cyclohexylene carbonate), random copolymer of ethylene
carbonate and propylene carbonate, random copolymer of propylenε carbonate and cyclohexene carbonate, block copolymer of ethylene carbonate and propylene carbonate, and block copolymer of propylene carbonate and cyclohexene carbonate.
Poly(alkylene carbonates) are made by a process which, for ease of reference, is referred to herein as the zinc catalyst process. In this process 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 5,025,676 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 thus obtained are amorphous, and are normally solid, that is, shaped articles of them maintain their shapes under the force of gravity at temperatures up to at least about 120°C. Their weight average molecular weights generally are in the range from about 50,000 to about 800,00. The zinc catalyst process does not appear to be capable of making alkylene carbonate homo- and copolymer products predominate in homo- and copolymers of weight average molecular weight generally in the range from about 1,000 to about 50,000.
One of the utilities of poly(alkylene carbonates) is as sacrificial binders in the manufacture of articles from ceramic and metal powders. See, for example, the U.S. Patents 4,814,370 and 4,882,110 of Kramer et al . , and the U.S. Patent 5,089,070 of
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McAndrew. In such manufacture the poly( alkylene carbonate) functions as a binder of the powder until the shaped "green" articles thereof are sintered to fuse together the ceramic or metallic particles. The sintering step is carried out at temperatures at which the poly(alkylene carbonate) binder thermally decomposes or burns (when the step is done without the exclusion of air) .
Recently, it has become apparent that poly( alkylene carbonates) of lower molecular weights, that is, of shorter polymer chain lengths, than poly(alkylene carbonates) of higher molecular weights, and particularly those made by the zinc catalyst process, might be more advantageous as sacrificial binders in ceramic technologies being developed. Poly( alkylene carbonates) of lower molecular weights tend to thermally decompose at lower temperatures and at faster rates than the higher molecular weight alkylene carbonate polymers .
SUMMARY OF THE INVENTION
In summary, the invention hereof provides a process for obtaining a lower molecular weight poly( alkylene carbonate) from a higher molecular weight poly( alkylene carbonate). Specific embodiments of the process enables the production of poly(alkylene carbonates) of weight average molecular weights of about 1,000-50,000 from poly( alkylene carbonates) made by the zinc catalyst process, that is, poly( alkylene carbonates) of weight average molecular weights of about 50,000-800,000.
The process comprises:
(a) admixing hydroxy material with the higher molecular weight poly( alkylene carbonate), the hydroxy material being selected from the group consisting of water and normally liquid, hydroxy aliphatic compounds;
(b) treating the resulting mixture by (i) establishing it in a treatment temperature range
generally of about 100-220°C, and under pressure sufficient to maintain the hydroxy material in the liquid state; and (ii) maintaining the mixture under these conditions for a period of time sufficient for substantially all of the higher molecular weight poly( alkylene carbonate) to form poly( alkylene carbonate) of the desired lower molecular weight.
The reaction mixture thus obtained consists essentially of lower molecular weight poly(alkylene carbonate). In most embodiments of the process, lower molecular weight poly(alkylene carbonate) is separated from the reaction mixture.
DETAILED DESCRIPTION OF THE INVENTION
The hydroxy material comprises 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 atmospheric pressure. Preferred normally liquid, hydroxy aliphatic compounds are 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, the hεxyl alchols the alicyclic alcohols including cyclohexanol and the like, and such polyhydric aliphatic alcohols as glycerol and the like.
The quantity of hydroxy material admixed with the physical combination should be about 1-30%, preferably 3-10%, by weight of the higher molecular weight poly( alkylene carbonate).
It is within the concepts of this invention to include in the mixture of hydroxy material and higher molecular weight poly(alkylene carbonate) a catalytically effective quantity of catalyst material that causes substantial reduction of the minimum temperature at which occurs significant degradation of
the poly(alkylene carbonatε), substantial accelεration of thε degradation of the poly( alkylene carbonate), or both such reduction and acceleration. The catalyst material comprises one or more than one catalyst. Examples of the catalyst or catalysts include transesterification 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 higher molecular weight poly( alkylene carbonate).
In general the temperature range in which the mixture of the physical combination and the hydroxy material is treated is as set forth above.
The pressure under which the initial mixture of hydroxy material and the higher molecular weight poly( alkylene carbonate), and the resulting reaction mixture, is established and maintained during the treating step is dependent on the temperature or temperatures at which the initial and resulting mixtures are established and maintained. In the above specified general temperature range, a pressure of about 20-200 psi (about 0.1-1.4 MPa) , preferably 50-150 psi (about 0.3-1 MPa) , usually is adequate .
Thε pεriod of time the highεr molεcular wεight poly( alkylene carbonatε) is subjεcted to these conditions is dependεnt on the number of carbons in the alkylεne moieties of, and the number of monomeric units in, the polymer chains. In general, the higher the molecular weight of a poly(alkylene carbonate) the longer is the time to degrade it at a givεn te peraturε. Also, thε higher the number of carbon atoms in the alkylene carbonatε monomeric units of a poly(alkylene carbonate) the higher the tεmpεrature should be for its degradation. In gεnεral, howevεr, the range of the period of time is from about five minutεε to about fifty hours. In somε εmbodimεnts of thε procεss, pεriods of ti ε within this range are selεctεd to rεsult in lower molecular weight poly(alkylεnε carbonate) that is still solid at 20-25°C. Howevεr, in other embodiments longεr pεriods of timε arε
selεctεd to give lower molεcular weight poly( alkylεne carbonate) that at 20-25°C is a viscous liquid. Preferably, the pεriod of trεatmεnt timε is insufficiεnt to form more than a quantatively minor amount of alkylene carbonate. To dεtermine the optimum time to obtain a desired lower molecular weight poly( alkylene carbonate), it is recommεnded that a batch mode trial run be made at a tεmperature in the treat εnt tεmperature range, and under pressurε sufficient to keep the hydroxy matεrial in thε rεaction mixture, that is, keep it liquid, and during the run periodically withdraw a sample of thε reaction mixture for analysis of the lower molεcular weight poly( alkylene carbonate) content and alkylenε carbonatε(s) content thεrεof.
In preferred embodimεnts of the process, lower molεcular wεight poly( alkylεnε carbonatε) is isolated from the reaction mixture. This can be done by cooling the reaction mixture to room te pεraturε (20-25°C). Regardless of whethεr thε lowεr molεcular wεight poly( alkylεnε carbonate) is solid or liquid at this temperature, it is not in solution in the hydroxy material. It is either a solid or a liquid immiscible with the hydroxy material. In a broad sensε, it and thε hydroxy matεrial arε segregated. Hencε, after cooling the reaction mixture to the indicated temperature, lower molecular weight poly(alkylenε carbonatε) product is separated by conventional ways and means for separating solids from liquids, or separating immiscible liquids. Such ways and mεans includε filtration (whεn thε product is solid), dεcantation, cεntrifugation, εvaporation of hydroxy material by the application of heat, vacuum, or both, and the like.
Thε process of the invention can bε practiced in batch modε or in continuous modε. In eithεr modε, convεntional equipment appropriate for the modε is εmployed. However, in εithεr mode the preferred practice includes carrying out the admixing and treatmεnt stεps with good, constant mixing action.
The degradεd polymer product of thε procεss usually comprisεs not only lowεr molecular weight poly(alkylεne carbonate), but
also alkylεnε carbonatε, or alkylεnε carbonates if the higher molecular weight poly( alkylene carbonatε) had differεnt alkylεnε carbonatε monomεric units. Thε concεntration of thε alkylεnε carbonate(s) is depεndent on the length of time the polymeric material is subjεctεd to thε abovε εlεvated tempεraturε and pressure conditions. This alkylenε carbonatε(s) contεnt can bε of advantagε as a plasticizεr of thε lowεr molecular weight poly(alkylenε carbonatε) when it is normally solid, and the dεgraded polymer product alone or with other matεrial is extruded, injection molded or the like. However, when it is not wanted or its concentration must be reduced to an acceptablε lεvεl, thε alkylεnε carbonatε(s) contεnt in wholε or in part is sεparated from the lower molecular weight poly(alkylene carbonate) by extraction with a solvent (for example, ethanol) for the alkylene carbonate(s) content.
The lower molecular weight poly( alkylene carbonate) thus obtainεd has utility as a sacrificial bindεr in thε manufacturε of articlεs from cεramic, mεtallic and glass powdεrs in those instances wherε it is dεεired or requirεd that the binder thermally decomposε or burn at a tεmpεraturε substantially lower than the thermal decomposition or burning tempεraturε of thε highεr molεcular wεight poly(alkylεnε carbonate) . Becauεε the polymer chains of the lowεr molεcular wεight poly( alkylεne carbonate) are hydroxy terminatεd, thε lower molecular weight poly(alkylenε carbonatε) also has utility as an isocyanate reactive reagεnt in thε production of polyurεthanes and articles therefrom. In addition, it has utility in the photolithographic artε. For example, the hydroxyl oietiεε thεrεof can bε reacted with an alkenylacyl halidε (for εxamplε, acryloyl chloridε) or an alkεnyl carboxylic acid (for εxamplε, mεthacrylic acid) to form functional groupε that, with thε aid of a convεntional chemical initiator, can be croεε-linked with molecular energizing radiation εuch aε light. The thus functionalized, lowεr molεcular wεight poly( alkylεnε carbonate) is useful as a nεgativε rεsist in photolithography.
On thε baεiε of prεliminary work with poly( εthylεnε carbonate),
the weight averagε molεcular wεight of which was 87,000, and poly(propylεne carbonate), the weight average molecular weight of which was 195,000, the following tεmpεratures and reaction times are recommended for the molecular weight reduction of these and similar highεr molecular weight PECs and PPCε:
Hydroxy % By Wt Temp Reaction Desired Product
PAC Matεrial of PAC °C Time (min) Of Deσradation
PEC Watεr 30 170 45 LOW MW PEC
PEC Glycεrol 8.9 170 20 LOW MW PEC
PPC Water 15 170 60 LOW MW PPC
PPC Glycerol 10 170 120 LOW MW PPC
In thε abovε tablε, "wt" εans weight, "PAC" meanε "poly( alkylεnε carbonatε)", "PEC" mεanε poly(εthylεnε carbonate), "PPC" poly(propylenε carbonatε), "tεmp" mεans tεmpεraturε, "min" mεans minutεs, and "MW" meanε weight average molecular weight.
In preliminary work the treatment according to the proceεε of thiε invεntion of a random copolymer of propylenε carbonatε and cyclohexene carbonatε, the contεnt of propylεnε carbonatε unitε being 30 mol%, thε contεnt of cyclohexenε carbonatε units being 70 mol%, and thε wεight avεrage molecular weight of which was 211,000, resultεd in a lowεr molεcular wεight random copolymer of propylene carbonate and cyclohexεnε carbonatε. In such work thε hydroxy material consisted of watεr, thε quantity of which was 15% by wεight of thε copolymεr, thε trεatmεnt tempεraturε was 190°C, and thε treatment time was 5 hours.
Other featurεs, embodiments and advantages of thε invεntion will become readily apparent to those in the exεrcisε of ordinary εkill in the art after rεading thε forεgoing disclosurεs. Such embodiments are within the spirit and scopε of thε invention aε disclosed.
Thε εxprεsεion "consisting essentially of" as used herein excludes an unrecitεd substancε at a concεntration sufficiεnt to
substantially adversely affect thε eεsential propεrties and characteriεtics of thε composition of attεr bεing defined, whilε pεrmitting thε presence of one or morε than one unrecited substance at a concentration or concεntrations insufficiεnt to substantially adversely affεct said εssεntial properties and charcteristics .
Claims
1. A process for obtaining a lower molecular weight poly(alkylεne carbonate) from a higher molεcular weight poly( alkylenε carbonatε), which comprisεε:
(a) admixing hydroxy matεrial with the higher molecular weight poly(alkylenε carbonatε), thε hydroxy matεrial bεing sεlεcted from the group consisting of watεr and normally liquid, hydroxy aliphatic organic compounds;
(b) trεating the resulting mixture by (i) establishing it in a trεatmεnt temperaturε rangε genεrally of about 100-220°C, and under presεurε sufficiεnt to maintain thε hydroxy matεrial in thε liquid statε; and (ii) maintaining thε mixturε undεr thεεe conditionε for a period of timε εufficiεnt for εubstantially all of thε higher molecular weight poly(alkylεne carbonate) to form poly(alkylene carbonate) of thε dεsirεd lower molecular wεight.
2. A procεεε according to claim 1, whεrεin a lower molεcular wεight poly(alkylεnε carbonatε) product is isolated from the resulting reaction mixture.
3. A procesε according to claim 2 in which the product is isolated by cooling thε rεaction mixturε to 20-25°C, and sεparating rεsulting sεgrεgated product from the mixture.
4. A procεss according to claim 1 in which thε weight avεragε molεcular wεight of thε highεr molεcular wεight poly( alkylεne carbonate) is about 50,000-800,00.
5. A proceεs according to claim 4 in which thε wεight avεragε molεcular weight of the lower molecular weight poly( alkylenε carbonatε) is about 1,000-50,000.
6. A procεεε according to claim 5 in which thε highεr molεcular weight poly( alkylene carbonate) iε poly(ethylεnε carbonate) or poly(propylenε carbonatε) .
7. A process according to claim 6 in which the hydroxy material consists esεεntially of watεr or glycεrol.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US11423898P | 1998-12-30 | 1998-12-30 | |
| US60/114,238 | 1998-12-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2000039172A1 true WO2000039172A1 (en) | 2000-07-06 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US1999/031130 WO2000039172A1 (en) | 1998-12-30 | 1999-12-29 | Process for obtaining lower molecular weight poly(alkylene carbonate) from higher molecular weight poly(alkylene carbonate) |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2000039172A1 (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7858204B2 (en) | 2006-05-25 | 2010-12-28 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering |
| USRE42329E1 (en) | 2002-07-24 | 2011-05-10 | Lucas-Milhaupt, Inc. | Flux cored preforms for brazing |
| EP2557104A1 (en) | 2011-08-12 | 2013-02-13 | Basf Se | Method for producing low molecular weight polyalkylene carbonate |
| US9095937B2 (en) | 2006-05-25 | 2015-08-04 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering and method of making and using same |
| US9157134B2 (en) | 2009-10-26 | 2015-10-13 | Lucas-Milhaupt, Inc. | Low silver, low nickel brazing material |
| US9314862B2 (en) | 2013-05-30 | 2016-04-19 | Lucas-Milhaupt, Inc. | Process for flux coating braze preforms and discrete parts |
| US9731383B2 (en) | 2014-07-09 | 2017-08-15 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering and method of using same |
| US10744601B2 (en) | 2015-08-07 | 2020-08-18 | Bellman-Melcor Development, Llc | Bonded brazing ring system and method for adhering a brazing ring to a tube |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3585168A (en) * | 1968-09-21 | 1971-06-15 | Shohei Inoue | Process for producing copolymer of epoxide and carbon dioxide |
| US4665136A (en) * | 1986-04-07 | 1987-05-12 | Air Products And Chemicals, Inc. | Process for producing novel block alkylene polycarbonate copolymers |
| US4763715A (en) * | 1987-12-14 | 1988-08-16 | Arco Chemical Company | Process for preparing polycarbonate terpolymer foam suitable for lost foam casting |
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1999
- 1999-12-29 WO PCT/US1999/031130 patent/WO2000039172A1/en active Application Filing
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3585168A (en) * | 1968-09-21 | 1971-06-15 | Shohei Inoue | Process for producing copolymer of epoxide and carbon dioxide |
| US4665136A (en) * | 1986-04-07 | 1987-05-12 | Air Products And Chemicals, Inc. | Process for producing novel block alkylene polycarbonate copolymers |
| US4763715A (en) * | 1987-12-14 | 1988-08-16 | Arco Chemical Company | Process for preparing polycarbonate terpolymer foam suitable for lost foam casting |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| USRE42329E1 (en) | 2002-07-24 | 2011-05-10 | Lucas-Milhaupt, Inc. | Flux cored preforms for brazing |
| USRE44343E1 (en) | 2002-07-24 | 2013-07-09 | Lucas-Milhaupt, Inc. | Flux cored preforms for brazing |
| US7858204B2 (en) | 2006-05-25 | 2010-12-28 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering |
| US9095937B2 (en) | 2006-05-25 | 2015-08-04 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering and method of making and using same |
| US10071445B2 (en) | 2006-05-25 | 2018-09-11 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering and method of making and using same |
| US9157134B2 (en) | 2009-10-26 | 2015-10-13 | Lucas-Milhaupt, Inc. | Low silver, low nickel brazing material |
| EP2557104A1 (en) | 2011-08-12 | 2013-02-13 | Basf Se | Method for producing low molecular weight polyalkylene carbonate |
| US9314862B2 (en) | 2013-05-30 | 2016-04-19 | Lucas-Milhaupt, Inc. | Process for flux coating braze preforms and discrete parts |
| US9731383B2 (en) | 2014-07-09 | 2017-08-15 | Bellman-Melcor Development, Llc | Filler metal with flux for brazing and soldering and method of using same |
| US10744601B2 (en) | 2015-08-07 | 2020-08-18 | Bellman-Melcor Development, Llc | Bonded brazing ring system and method for adhering a brazing ring to a tube |
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