JP2004043637A - Glycolic acid copolymer - Google Patents
Glycolic acid copolymer Download PDFInfo
- Publication number
- JP2004043637A JP2004043637A JP2002202813A JP2002202813A JP2004043637A JP 2004043637 A JP2004043637 A JP 2004043637A JP 2002202813 A JP2002202813 A JP 2002202813A JP 2002202813 A JP2002202813 A JP 2002202813A JP 2004043637 A JP2004043637 A JP 2004043637A
- Authority
- JP
- Japan
- Prior art keywords
- glycolic acid
- molecular weight
- acid copolymer
- polymerization
- average molecular
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Natural products OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 title claims abstract description 92
- 229920001577 copolymer Polymers 0.000 title claims abstract description 50
- 238000006068 polycondensation reaction Methods 0.000 claims abstract description 35
- 238000004519 manufacturing process Methods 0.000 claims abstract description 19
- -1 phosphite compound Chemical class 0.000 claims abstract description 19
- 230000008859 change Effects 0.000 claims abstract description 13
- 238000004040 coloring Methods 0.000 claims description 41
- 229910052751 metal Inorganic materials 0.000 claims description 23
- 239000002184 metal Substances 0.000 claims description 23
- 150000004703 alkoxides Chemical class 0.000 claims description 21
- 239000003054 catalyst Substances 0.000 claims description 14
- 238000002844 melting Methods 0.000 claims description 11
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 10
- 230000008018 melting Effects 0.000 claims description 10
- 239000002994 raw material Substances 0.000 claims description 9
- BVKZGUZCCUSVTD-UHFFFAOYSA-N carbonic acid Chemical compound OC(O)=O BVKZGUZCCUSVTD-UHFFFAOYSA-N 0.000 claims description 8
- 229910052772 Samarium Inorganic materials 0.000 claims description 6
- 229910052787 antimony Inorganic materials 0.000 claims description 6
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 claims description 6
- 229910052746 lanthanum Inorganic materials 0.000 claims description 6
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 claims description 6
- KZUNJOHGWZRPMI-UHFFFAOYSA-N samarium atom Chemical compound [Sm] KZUNJOHGWZRPMI-UHFFFAOYSA-N 0.000 claims description 6
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 5
- 229910052732 germanium Inorganic materials 0.000 claims description 5
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 5
- 229910052735 hafnium Inorganic materials 0.000 claims description 5
- VBJZVLUMGGDVMO-UHFFFAOYSA-N hafnium atom Chemical compound [Hf] VBJZVLUMGGDVMO-UHFFFAOYSA-N 0.000 claims description 5
- 230000003301 hydrolyzing effect Effects 0.000 claims description 5
- 229910052742 iron Inorganic materials 0.000 claims description 5
- 239000011777 magnesium Substances 0.000 claims description 5
- 229910052749 magnesium Inorganic materials 0.000 claims description 5
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052718 tin Inorganic materials 0.000 claims description 3
- 238000010128 melt processing Methods 0.000 abstract description 5
- 238000002845 discoloration Methods 0.000 abstract 2
- 238000006116 polymerization reaction Methods 0.000 description 56
- 229920000642 polymer Polymers 0.000 description 48
- 238000000034 method Methods 0.000 description 24
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 18
- 239000007789 gas Substances 0.000 description 12
- 239000000155 melt Substances 0.000 description 12
- 238000006243 chemical reaction Methods 0.000 description 11
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 10
- 239000011261 inert gas Substances 0.000 description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 10
- JKIJEFPNVSHHEI-UHFFFAOYSA-N Phenol, 2,4-bis(1,1-dimethylethyl)-, phosphite (3:1) Chemical compound CC(C)(C)C1=CC(C(C)(C)C)=CC=C1OP(OC=1C(=CC(=CC=1)C(C)(C)C)C(C)(C)C)OC1=CC=C(C(C)(C)C)C=C1C(C)(C)C JKIJEFPNVSHHEI-UHFFFAOYSA-N 0.000 description 8
- 238000002425 crystallisation Methods 0.000 description 8
- 229910052757 nitrogen Inorganic materials 0.000 description 8
- 239000007790 solid phase Substances 0.000 description 8
- HVLLSGMXQDNUAL-UHFFFAOYSA-N triphenyl phosphite Chemical compound C=1C=CC=CC=1OP(OC=1C=CC=CC=1)OC1=CC=CC=C1 HVLLSGMXQDNUAL-UHFFFAOYSA-N 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 230000008025 crystallization Effects 0.000 description 7
- 238000011156 evaluation Methods 0.000 description 7
- LMDQRKJROSLEEI-UHFFFAOYSA-N germanium(4+) propan-2-olate Chemical compound [Ge+4].CC(C)[O-].CC(C)[O-].CC(C)[O-].CC(C)[O-] LMDQRKJROSLEEI-UHFFFAOYSA-N 0.000 description 7
- 239000000047 product Substances 0.000 description 7
- 229920000954 Polyglycolide Polymers 0.000 description 6
- 150000001875 compounds Chemical class 0.000 description 6
- MTHSVFCYNBDYFN-UHFFFAOYSA-N diethylene glycol Chemical compound OCCOCCO MTHSVFCYNBDYFN-UHFFFAOYSA-N 0.000 description 6
- OJMIONKXNSYLSR-UHFFFAOYSA-N phosphorous acid Chemical compound OP(O)O OJMIONKXNSYLSR-UHFFFAOYSA-N 0.000 description 6
- 230000018044 dehydration Effects 0.000 description 5
- 238000006297 dehydration reaction Methods 0.000 description 5
- 239000004633 polyglycolic acid Substances 0.000 description 5
- BYEAHWXPCBROCE-UHFFFAOYSA-N 1,1,1,3,3,3-hexafluoropropan-2-ol Chemical compound FC(F)(F)C(O)C(F)(F)F BYEAHWXPCBROCE-UHFFFAOYSA-N 0.000 description 4
- ADCOVFLJGNWWNZ-UHFFFAOYSA-N antimony trioxide Chemical compound O=[Sb]O[Sb]=O ADCOVFLJGNWWNZ-UHFFFAOYSA-N 0.000 description 4
- 239000012298 atmosphere Substances 0.000 description 4
- 238000006460 hydrolysis reaction Methods 0.000 description 4
- JVTAAEKCZFNVCJ-UHFFFAOYSA-N lactic acid Chemical compound CC(O)C(O)=O JVTAAEKCZFNVCJ-UHFFFAOYSA-N 0.000 description 4
- 238000000465 moulding Methods 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000008188 pellet Substances 0.000 description 4
- 229920000747 poly(lactic acid) Polymers 0.000 description 4
- 239000000523 sample Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- VXUYXOFXAQZZMF-UHFFFAOYSA-N titanium(IV) isopropoxide Chemical compound CC(C)O[Ti](OC(C)C)(OC(C)C)OC(C)C VXUYXOFXAQZZMF-UHFFFAOYSA-N 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 239000002253 acid Substances 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 3
- 125000004429 atom Chemical group 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005227 gel permeation chromatography Methods 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 230000007062 hydrolysis Effects 0.000 description 3
- JJTUDXZGHPGLLC-UHFFFAOYSA-N lactide Chemical compound CC1OC(=O)C(C)OC1=O JJTUDXZGHPGLLC-UHFFFAOYSA-N 0.000 description 3
- 125000004430 oxygen atom Chemical group O* 0.000 description 3
- 239000004626 polylactic acid Substances 0.000 description 3
- HJCRVWSKQNDSPZ-UHFFFAOYSA-N propan-2-olate;samarium(3+) Chemical compound [Sm+3].CC(C)[O-].CC(C)[O-].CC(C)[O-] HJCRVWSKQNDSPZ-UHFFFAOYSA-N 0.000 description 3
- UYCAUPASBSROMS-AWQJXPNKSA-M sodium;2,2,2-trifluoroacetate Chemical compound [Na+].[O-][13C](=O)[13C](F)(F)F UYCAUPASBSROMS-AWQJXPNKSA-M 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- RKDVKSZUMVYZHH-UHFFFAOYSA-N 1,4-dioxane-2,5-dione Chemical compound O=C1COC(=O)CO1 RKDVKSZUMVYZHH-UHFFFAOYSA-N 0.000 description 2
- UGAGPNKCDRTDHP-UHFFFAOYSA-N 16-hydroxyhexadecanoic acid Chemical compound OCCCCCCCCCCCCCCCC(O)=O UGAGPNKCDRTDHP-UHFFFAOYSA-N 0.000 description 2
- WHBMMWSBFZVSSR-UHFFFAOYSA-N 3-hydroxybutyric acid Chemical compound CC(O)CC(O)=O WHBMMWSBFZVSSR-UHFFFAOYSA-N 0.000 description 2
- FMHKPLXYWVCLME-UHFFFAOYSA-N 4-hydroxy-valeric acid Chemical compound CC(O)CCC(O)=O FMHKPLXYWVCLME-UHFFFAOYSA-N 0.000 description 2
- RVDLHGSZWAELAU-UHFFFAOYSA-N 5-tert-butylthiophene-2-carbonyl chloride Chemical compound CC(C)(C)C1=CC=C(C(Cl)=O)S1 RVDLHGSZWAELAU-UHFFFAOYSA-N 0.000 description 2
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 2
- 229930182843 D-Lactic acid Natural products 0.000 description 2
- JVTAAEKCZFNVCJ-UWTATZPHSA-N D-lactic acid Chemical compound C[C@@H](O)C(O)=O JVTAAEKCZFNVCJ-UWTATZPHSA-N 0.000 description 2
- PEDCQBHIVMGVHV-UHFFFAOYSA-N Glycerine Chemical compound OCC(O)CO PEDCQBHIVMGVHV-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- OFOBLEOULBTSOW-UHFFFAOYSA-N Malonic acid Chemical compound OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 2
- WNLRTRBMVRJNCN-UHFFFAOYSA-N adipic acid Chemical compound OC(=O)CCCCC(O)=O WNLRTRBMVRJNCN-UHFFFAOYSA-N 0.000 description 2
- 229920003232 aliphatic polyester Polymers 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- QMKYBPDZANOJGF-UHFFFAOYSA-N benzene-1,3,5-tricarboxylic acid Chemical compound OC(=O)C1=CC(C(O)=O)=CC(C(O)=O)=C1 QMKYBPDZANOJGF-UHFFFAOYSA-N 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- 238000011088 calibration curve Methods 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000007334 copolymerization reaction Methods 0.000 description 2
- 229940022769 d- lactic acid Drugs 0.000 description 2
- 150000001991 dicarboxylic acids Chemical class 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 150000002009 diols Chemical class 0.000 description 2
- 238000010828 elution Methods 0.000 description 2
- JTPUGUWXHGEEHW-UHFFFAOYSA-N ethanolate;iron(3+) Chemical compound [Fe+3].CC[O-].CC[O-].CC[O-] JTPUGUWXHGEEHW-UHFFFAOYSA-N 0.000 description 2
- LNTHITQWFMADLM-UHFFFAOYSA-N gallic acid Chemical compound OC(=O)C1=CC(O)=C(O)C(O)=C1 LNTHITQWFMADLM-UHFFFAOYSA-N 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 239000011491 glass wool Substances 0.000 description 2
- 150000004676 glycans Chemical class 0.000 description 2
- WZVIPWQGBBCHJP-UHFFFAOYSA-N hafnium(4+);2-methylpropan-2-olate Chemical compound [Hf+4].CC(C)(C)[O-].CC(C)(C)[O-].CC(C)(C)[O-].CC(C)(C)[O-] WZVIPWQGBBCHJP-UHFFFAOYSA-N 0.000 description 2
- 239000004310 lactic acid Substances 0.000 description 2
- 235000014655 lactic acid Nutrition 0.000 description 2
- SORGMJIXNUWMMR-UHFFFAOYSA-N lanthanum(3+);propan-2-olate Chemical compound [La+3].CC(C)[O-].CC(C)[O-].CC(C)[O-] SORGMJIXNUWMMR-UHFFFAOYSA-N 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000014759 maintenance of location Effects 0.000 description 2
- WXZMFSXDPGVJKK-UHFFFAOYSA-N pentaerythritol Chemical compound OCC(CO)(CO)CO WXZMFSXDPGVJKK-UHFFFAOYSA-N 0.000 description 2
- WLJVNTCWHIRURA-UHFFFAOYSA-N pimelic acid Chemical compound OC(=O)CCCCCC(O)=O WLJVNTCWHIRURA-UHFFFAOYSA-N 0.000 description 2
- 229920003229 poly(methyl methacrylate) Polymers 0.000 description 2
- 239000004926 polymethyl methacrylate Substances 0.000 description 2
- 229920001282 polysaccharide Polymers 0.000 description 2
- 239000005017 polysaccharide Substances 0.000 description 2
- 239000001294 propane Substances 0.000 description 2
- CYIDZMCFTVVTJO-UHFFFAOYSA-N pyromellitic acid Chemical compound OC(=O)C1=CC(C(O)=O)=C(C(O)=O)C=C1C(O)=O CYIDZMCFTVVTJO-UHFFFAOYSA-N 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007151 ring opening polymerisation reaction Methods 0.000 description 2
- 239000012488 sample solution Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- KQTIIICEAUMSDG-UHFFFAOYSA-N tricarballylic acid Chemical compound OC(=O)CC(C(O)=O)CC(O)=O KQTIIICEAUMSDG-UHFFFAOYSA-N 0.000 description 2
- ARCGXLSVLAOJQL-UHFFFAOYSA-N trimellitic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C(C(O)=O)=C1 ARCGXLSVLAOJQL-UHFFFAOYSA-N 0.000 description 2
- AUPYNGCJRYOPQY-UHFFFAOYSA-N tris(2,5-ditert-butylphenyl) phosphite Chemical compound CC(C)(C)C1=CC=C(C(C)(C)C)C(OP(OC=2C(=CC=C(C=2)C(C)(C)C)C(C)(C)C)OC=2C(=CC=C(C=2)C(C)(C)C)C(C)(C)C)=C1 AUPYNGCJRYOPQY-UHFFFAOYSA-N 0.000 description 2
- SZPHBONKPMLMCA-UHFFFAOYSA-N tris(2-tert-butylphenyl) phosphite Chemical compound CC(C)(C)C1=CC=CC=C1OP(OC=1C(=CC=CC=1)C(C)(C)C)OC1=CC=CC=C1C(C)(C)C SZPHBONKPMLMCA-UHFFFAOYSA-N 0.000 description 2
- DNIAPMSPPWPWGF-VKHMYHEASA-N (+)-propylene glycol Chemical compound C[C@H](O)CO DNIAPMSPPWPWGF-VKHMYHEASA-N 0.000 description 1
- FEODVXCWZVOEIR-UHFFFAOYSA-N (2,4-ditert-butylphenyl) octyl hydrogen phosphite Chemical compound CCCCCCCCOP(O)OC1=CC=C(C(C)(C)C)C=C1C(C)(C)C FEODVXCWZVOEIR-UHFFFAOYSA-N 0.000 description 1
- LNAZSHAWQACDHT-XIYTZBAFSA-N (2r,3r,4s,5r,6s)-4,5-dimethoxy-2-(methoxymethyl)-3-[(2s,3r,4s,5r,6r)-3,4,5-trimethoxy-6-(methoxymethyl)oxan-2-yl]oxy-6-[(2r,3r,4s,5r,6r)-4,5,6-trimethoxy-2-(methoxymethyl)oxan-3-yl]oxyoxane Chemical compound CO[C@@H]1[C@@H](OC)[C@H](OC)[C@@H](COC)O[C@H]1O[C@H]1[C@H](OC)[C@@H](OC)[C@H](O[C@H]2[C@@H]([C@@H](OC)[C@H](OC)O[C@@H]2COC)OC)O[C@@H]1COC LNAZSHAWQACDHT-XIYTZBAFSA-N 0.000 description 1
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- YPFDHNVEDLHUCE-UHFFFAOYSA-N 1,3-propanediol Substances OCCCO YPFDHNVEDLHUCE-UHFFFAOYSA-N 0.000 description 1
- 238000005160 1H NMR spectroscopy Methods 0.000 description 1
- SDTMFDGELKWGFT-UHFFFAOYSA-N 2-methylpropan-2-olate Chemical compound CC(C)(C)[O-] SDTMFDGELKWGFT-UHFFFAOYSA-N 0.000 description 1
- SJZRECIVHVDYJC-UHFFFAOYSA-N 4-hydroxybutyric acid Chemical compound OCCCC(O)=O SJZRECIVHVDYJC-UHFFFAOYSA-N 0.000 description 1
- 229940006015 4-hydroxybutyric acid Drugs 0.000 description 1
- PHOJOSOUIAQEDH-UHFFFAOYSA-N 5-hydroxypentanoic acid Chemical compound OCCCCC(O)=O PHOJOSOUIAQEDH-UHFFFAOYSA-N 0.000 description 1
- IWHLYPDWHHPVAA-UHFFFAOYSA-N 6-hydroxyhexanoic acid Chemical compound OCCCCCC(O)=O IWHLYPDWHHPVAA-UHFFFAOYSA-N 0.000 description 1
- 229920000945 Amylopectin Polymers 0.000 description 1
- 229920002101 Chitin Polymers 0.000 description 1
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- 229920002307 Dextran Polymers 0.000 description 1
- 229920001353 Dextrin Polymers 0.000 description 1
- 239000004375 Dextrin Substances 0.000 description 1
- QEVGZEDELICMKH-UHFFFAOYSA-N Diglycolic acid Chemical compound OC(=O)COCC(O)=O QEVGZEDELICMKH-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000001856 Ethyl cellulose Substances 0.000 description 1
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- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- KDYFGRWQOYBRFD-UHFFFAOYSA-N Succinic acid Natural products OC(=O)CCC(O)=O KDYFGRWQOYBRFD-UHFFFAOYSA-N 0.000 description 1
- ZJCCRDAZUWHFQH-UHFFFAOYSA-N Trimethylolpropane Chemical compound CCC(CO)(CO)CO ZJCCRDAZUWHFQH-UHFFFAOYSA-N 0.000 description 1
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- FJWGYAHXMCUOOM-QHOUIDNNSA-N [(2s,3r,4s,5r,6r)-2-[(2r,3r,4s,5r,6s)-4,5-dinitrooxy-2-(nitrooxymethyl)-6-[(2r,3r,4s,5r,6s)-4,5,6-trinitrooxy-2-(nitrooxymethyl)oxan-3-yl]oxyoxan-3-yl]oxy-3,5-dinitrooxy-6-(nitrooxymethyl)oxan-4-yl] nitrate Chemical compound O([C@@H]1O[C@@H]([C@H]([C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O)O[C@H]1[C@@H]([C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@@H](CO[N+]([O-])=O)O1)O[N+]([O-])=O)CO[N+](=O)[O-])[C@@H]1[C@@H](CO[N+]([O-])=O)O[C@@H](O[N+]([O-])=O)[C@H](O[N+]([O-])=O)[C@H]1O[N+]([O-])=O FJWGYAHXMCUOOM-QHOUIDNNSA-N 0.000 description 1
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- CJZGTCYPCWQAJB-UHFFFAOYSA-L calcium stearate Chemical compound [Ca+2].CCCCCCCCCCCCCCCCCC([O-])=O.CCCCCCCCCCCCCCCCCC([O-])=O CJZGTCYPCWQAJB-UHFFFAOYSA-L 0.000 description 1
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- 150000002148 esters Chemical class 0.000 description 1
- CTCOPPBXAFHGRB-UHFFFAOYSA-N ethanolate;germanium(4+) Chemical compound [Ge+4].CC[O-].CC[O-].CC[O-].CC[O-] CTCOPPBXAFHGRB-UHFFFAOYSA-N 0.000 description 1
- HHFAWKCIHAUFRX-UHFFFAOYSA-N ethoxide Chemical compound CC[O-] HHFAWKCIHAUFRX-UHFFFAOYSA-N 0.000 description 1
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- 229940096919 glycogen Drugs 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
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Abstract
Description
【０００１】
【発明の属する技術分野】
本発明は、グリコール酸共重合体を製造する方法に関する。詳しくは、溶融加工時に着色することの少ないグリコール酸共重合体を製造する方法に関する。
【０００２】
【従来の技術】
ポリ乳酸、ポリグリコール酸又はこれらの共重合体に代表されるヒドロキシカルボン酸から製造される脂肪族ポリエステルは、生分解性の高分子として注目され、例えば、縫合糸等の医用材料、医薬、農薬、肥料等の徐放性材料等、多方面に利用されている。特に、ポリグリコール酸及びグリコール酸構造単位を主体とするグリコール酸共重合体は、ガスバリアー性に優れるという特徴を有し、フィルム等、包装材料用途に利用する提案が多数行われている。
【０００３】
これらのポリマーを製造する方法としては、従来、乳酸、グリコール酸を一旦重縮合し、プレポリマーとした後、解重合によりラクチド及び／又はグリコリドを製造し、これらを用いて開環重合してポリラクチド及びポリグリコリドを製造していた。この方法によると、高分子量のポリマーが得られるものの、多数の工程を必要とし、また、ラクチド、グリコリドを得るために多大の労力がかかり、経済的とはいえなかった。
【０００４】
本発明者らは、先に、特定の金属アルコキシドをグリコール酸存在下にて加水分解させることにより得られる加水分解生成物を触媒として用いて、グリコール酸等の原料を直接重縮合することにより、効率よく、高分子量で、重合時着色することの少ない高品質のグリコール酸共重合体が得られることを見出し、特許出願した（特願２００１−９３６７６号）。
しかしながら、グリコール酸構造単位を多く含むグリコール酸共重合体は、比較的高い融点を有するため、溶融加工時の温度が高くなり、成形加工等に供した場合、ポリマーの着色が著しかったり、大幅な分子量の低下がしばしば認められることがある。
【０００５】
このような問題を解決した、ポリ乳酸の製造方法として、特開平９−１５１２４３号公報には、ラクチドを錫等の金属触媒を用い、開環重合する際に、重合後半又は重合終了時にリン酸系エステルを添加することにより熱安定性、特に、分子量保持性に優れた高分子量のポリ乳酸を製造する方法が提案されている。しかしながら、この公報には、グリコール酸を出発原料としてポリグリコール酸及び／又はグリコール酸共重合体を製造する場合について、何ら記載されていない。本発明者らがグリコール酸共重合体を重縮合反応により製造する場合に、これを試みた結果では、融点以上、例えば、２３０℃での溶融保持時の分子量の保持性のわずかな改善が認められたものの、着色抑制効果に関しては満足できる効果が得られなかった。
このような事情に鑑み、重合時及び再溶融加工時にも着色することが少なく、高分子量を有するポリグリコール酸及び／又はグリコール酸共重合体を製造できる技術の登場が強く求められている。
【０００６】
【発明が解決しょうとする課題】
本発明の目的は、比較的高い温度における溶融加工においても着色が少なく、高い品質を維持できるグリコール酸共重合体及びそれを製造する方法を提供することを目的とする。
【０００７】
【課題を解決するための手段】
本発明者らは、前記の課題を解決するため、鋭意検討を行った結果、特定の重縮合触媒の存在下に重合を行い、特定の分子量以上に達した段階において、特定のリン含有化合物を添加することにより、重合時の着色を抑制できるだけでなく、得られたポリマーを重合温度よりも更に高い温度で溶融加工した場合にも、ポリマーが着色することの少ないグリコール酸共重合体が得られることを見出した。
【０００８】
すなわち、本発明は、以下のとおりである。
（１） 重量平均分子量が５万以上であり、グリコール酸単位を７５ｍｏｌ％以上含有し、２３０℃で５分間、加熱溶融した後の着色度変化率が、加熱前着色度に対して１１０〜３００％であることを特徴とするグリコール酸共重合体。
（２） 少なくともグリコール酸を含む原料を重縮合して、グリコール酸単位を７５ｍｏｌ％以上含有するグリコール酸共重合体を製造する方法であって、重縮合反応の進行過程において、重量平均分子量が３万以上に達した段階で、トリアリールホスファイト化合物を添加することを特徴とする（１）に記載のグリコール酸共重合体の製造方法。
（３） マグネシウム、鉄、ハフニウム、ゲルマニウム、アンチモン、錫、ランタン及びサマリウムからなる群より選ばれる少なくとも１種の金属のアルコキシドを、ヒドロキシカルボン酸存在下で加水分解させることにより得られる加水分解物を重縮合触媒として用いることを特徴とする（２）に記載のグリコール酸共重合体の製造方法。
【０００９】
以下、本発明について詳細に説明する。
本発明において、グリコール酸共重合体中に含まれるグリコール酸単位の含有率は７５ｍｏｌ％以上であり、好ましくは７５ｍｏｌ％以上、９９ｍｏｌ％以下の範囲、より好ましくは８０ｍｏｌ％以上、９５ｍｏｌ％以下の範囲、最も好ましくは８２ｍｏｌ％以上、９０ｍｏｌ％以下の範囲である。グリコール酸単位の含有率が７５ｍｏｌ％未満の場合には、得られる共重合体の強度、弾性率等の機械的物性、軟化温度等の熱的物性及びガスバリアー性が低下する。グリコール酸単位の含有量が９９ｍｏｌ％を超える場合には、共重合体の熱安定性が充分でなく、溶融成形加工時に熱分解して、着色及び分子量が低下しやすくなる傾向がある。
【００１０】
グリコール酸単位以外の共重合成分の例としては、他のヒドロキシカルボン酸、ジカルボン酸、ジオール、３価以上の多価化合物及び多糖類等を挙げることができるが、グリコール酸と共重合可能なものであればこれらに限定されるものではない。
他のヒドロキシカルボン酸の例としては、Ｌ−乳酸、Ｄ−乳酸、３−ヒドロキシ酪酸、４−ヒドロキシ酪酸、４−ヒドロキシ吉草酸、５−ヒドロキシ吉草酸及び６−ヒドロキシカプロン酸、１２−ヒドロキシステアリン酸、１６−ヒドロキシヘキサデカン酸等が挙げられる。
【００１１】
ジカルボン酸の例としては、例えば、コハク酸、シュウ酸、マロン酸、グルタン酸、アジピン酸、ピメリン酸、ジグリコール酸等の脂肪族ジカルボン酸等が挙げられる。
ジオールの例としては、例えば、エチレングリコール、ジエチレングリコール、トリエチレングリコール、プロピレングリコール、ジプロピレングリコール、１，３−プロパンジオール、１，４−ブタンジオール、ネオペンチルグリコール、１，６−ヘキサンジオール、及びジエチレングリコール等が挙げられる。
【００１２】
３価以上の多官能化合物の例としては、グリセリン、トリメチロールプロパン、ペンタエリスリトール、リンゴ酸、トリメリット酸、トリメシン酸、ピロメリット酸、トリカルバリル酸、没食子酸等が挙げられる。
多糖類の例としては、例えば、セルロース、硝酸セルロース、酢酸セルロース、メチルセルロース、エチルセルロース、ＣＭＣ（カルボキ シメチルセルロース）、ヘミセルロース、デンプン、アミロペクチン、デキストリン、デキストラン、グリコーゲン、ペクチン、キチン、 キトサン等及びこれらの混合物及びこれらの誘導体等が挙げられる。
【００１３】
共重合成分として好ましい例としては、Ｄ−乳酸及びＬ−乳酸が挙げられる。より好ましい例としては、Ｌ−乳酸が挙げられ、さらに好ましくは、光学純度が９５％以上、最も好ましくは９８％以上の、発酵法で製造されるＬ−乳酸である。所望により、上記の共重合成分の他に、グリコール酸単位を含むオリゴマーを一緒に用いることもできる。
これらのグリコール酸及び共重合成分は、固体状でも、水溶液の形でも、本発明のグリコール酸共重合体の製造に供することができる。
【００１４】
本発明のグリコール酸共重合体の重量平均分子量は５万以上であり、２３０℃で５分間、加熱溶融した後の着色度変化率が、加熱前着色度に対して１１０〜３００％である。
本発明で用いる重量平均分子量、及びグリコール酸共重合体の着色度及びその変化率については、後に述べる測定法により求められる。
グリコール酸共重合体の重量平均分子量が５万未満の場合には、成形加工に供するに充分な溶融粘度を有さず、得られる成形体も充分な強度をもたない。
【００１５】
本発明において用いる着色度変化率とは、グリコール酸共重合体を２３０℃で５分間、加熱溶融した後の着色度を加熱前着色度で除した値を百分率で表した値である。本発明において、着色度変化率が１１０〜３００％、好ましく１１０〜２５０％、最も好ましくは１１０〜２００％の範囲であることが重要である。着色度変化率が３００％を越えると、加工製品として品位が大幅に低下する。
本発明のグリコール酸共重合体の製造において、触媒として、マグネシウム、鉄、ハフニウム、ゲルマニウム、アンチモン、ランタン、及びサマリウムからなる群より選ばれる少なくとも１種の金属のアルコキシドを、ヒドロキシカルボン酸存在下、加水分解させることにより得られる加水分解物を用いることが好ましい。
【００１６】
この金属アルコキシドは、アルキル基が結合した酸素原子と金属原子との結合が少なくとも１つ以上分子内に存在する化合物である。アルキル基と酸素原子の結合したものとしては、例えば、メトキシド、エトキシド、ｎ−プロポキシド、ｉｓｏ−プロポキシド、ｎ−ブトキシド、ｉｓｏ−ブトキシド、ｔｅｒｔ−ブトキシド、ｎ−ヘキシルアルコキシド、２−ヘキシルアルコキシド等の１価のア ルコキシドや、エチレングリコキシド、１，２−プロパンジアルコキシド、１，３−プロパンアルコキシド、１，４−ブタンジアルコキシド等の２価のアルコキシド、ペンタエリスリトール等の４価のアルコキシド等が挙げられる。これらは、１種単独で、又は２種以上組み合わせて用いることができる。
【００１７】
アルキル基が結合した酸素原子と金属原子との結合の例としては、マグネシウムエトキシド、鉄トリエトキシド、ハフニウムテトラｔｅｒｔ−ブトキシド、ゲルマニウムテトラエトキシド、ゲルマニウムテトラｉｓｏ−プロポキシド、アンチモントリｉｓｏ−エトキシド、ランタントリｉｓｏ−プロポキシド、サマリウムｉｓｏ−プロポキシド等が挙げられる。
金属アルコキシドの加水分解物の詳細な化学構造は明確ではないが、金属アルコキシドがアルコールを脱離するとともに、水酸化物｛Ｍ−（ＯＨ）Ｘ｝、金属アルコキシドの縮重合反応物｛−Ｍ−Ｏ−Ｍ−｝、グリコール酸とのアルコール交換反応物｛Ｍ−（ＯＣＨ２ＣＯＯＨ）Ｘ｝、グリコール酸と反応した金属塩｛Ｍ−（ＯＣＯＣＨ２ＯＨ）Ｘ｝及び、グリコール酸の配位物等からなる、複数の化学構造を包含しているものと推測される。
【００１８】
金属アルコキシドの加水分解物を得る方法は、限定されるものではないが、例えば、（ａ）重縮合反応前に、予め、マグネシウム、鉄、ハフニウム、ゲルマニウム、アンチモン、ランタン及びサマリウムからなる群より選ばれる少なくとも１種の金属のアルコキシドを、グリコール酸と充分量の水を含む水溶液の存在下に加水分解させて加水分解物を調整する方法、（ｂ）マグネシウム、鉄、ハフニウム、ゲルマニウム、アンチモン、ランタン及びサマリウムからなる群より選ばれる少なくとも１種の金属のアルコキシドを、少なくとも３重量％を越える水及びグリコール酸を含む重合原料水溶液に添加し、脱水濃縮及び重縮合を行う工程中に、重合系中において加水分解物を形成させる方法等が挙げられる。工程が簡略化できる点からは、（ｂ）法の、重合系中において脱水濃縮及び重縮合反応とともに金属アルコキシドの加水分解物を形成させる方法が好ましい。
【００１９】
グリコール酸共重合体の重縮合触媒として用いる金属アルコキシドの加水分解物の添加量としては、モノマー１ｇ当たり、金属原子として、通常、１×１０−７〜１×１０−２モル、好ましくは３×１０−７〜１×１０−３モルの範囲である。添加量が１×１０−７モル未満の場合には、重縮合速度を高めることが困難になり、添加量が１×１０−２モルを越えると、重合ポリマーが着色する等、副反応が増大し、分子量の増大が認められない場合がある。
【００２０】
本発明において、重合段階で添加するトリアリールホスファイト化合物の例としては、亜リン酸トリフェニル、トリス（２−ｔｅｒｔ−ブチルフェニル）ホスファイト、トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイト、トリス（２，５−ジｔｅｒｔ−ブチルフェニル）ホスファイト、トリス（２−ｔｅｒｔ−ブチル−４−メチルフェニル）ホスファイト、トリス（２−ｔｅｒｔ−ブチル−５−メチルフェニル）ホスファイト、トリス（２−ｔｅｒｔ−ブチル−４，６−ジメチルフェニル）ホスファイト、トリスノニルフェニルホスファ イト、トリス（モノ及びジノニルフェニル）ホスファ イト、等を挙げることができる。好ましくは、亜リン酸トリフェニル、トリス（２−ｔｅｒｔ−ブチルフェニル）ホスファイト、トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイト、及びトリス（２，５−ジｔｅｒｔ−ブチルフェニル）ホスファイトが挙げられる。
【００２１】
トリアリールホスファイト化合物の添加量には制限はないが、重合に使用する触媒金属原子１モルに対して、通常、０．１〜１０モル、好ましくは０．３〜３モル、より好ましくは０．５〜２モルの範囲で用いる。添加量が０．１モル未満の場合には、溶融時の着色が充分に解消できないことがあり、１０モルを越えると、更に継続して重合を行う場合に分子量が増大せず、着色も逆に著しくなる場合がある。
【００２２】
本発明において、グリコール酸共重合体を製造する際にトリアリールホスファイト化合物を添加する時期としては、重合反応によりその重量平均分子量が好ましくは３万以上、より好ましくは５万以上に達した段階である。重量平均分子量が３万未満の段階で添加した場合には、本発明の目的とする着色抑制効果が発揮されない。また、その後の重合速度が低下し、高い分子量を有するグリコール酸共重合体が得られない。
【００２３】
本発明におけるグリコール酸共重合体の製造方法は限定されない。例えば、（Ａ）水及びグリコール酸を含む原料水溶液の、脱水濃縮工程からそれに続く溶融重縮合工程の任意の時点に、予め、金属アルコキシドをヒドロキシカルボン酸の存在下で加水分解して調整した触媒を添加して、溶融重縮合を行い、その重量平均分子量が３万以上に達した段階でトリアリールホスファイト化合物を添加し、グリコール酸共重合体を製造する方法、（Ｂ）水及びヒドロキシカルボン酸を含む重合原料水溶液に金属アルコキシドを添加した後、脱水濃縮工程及び溶融重縮合工程を実施することにより、重合系中において触媒を形成させ、溶融重縮合を行い、その重量平均分子量が３万以上に達した段階でトリアリールホスファイト化合物を添加し、グリコール酸共重合体を製造する方法、（Ｃ）（Ａ）又は（Ｂ）において、トリアリールホスファイトを添加することなく溶融重縮合を終了後、その重量平均分子量が３万以上に達した溶融ポリマーをペレット状に造粒する工程において、トリアリールホスファイト化合物を添加する方法、（Ｄ）（Ａ）又は（Ｂ）において、トリアリールホスファイトを添加することなく溶融重縮合を終了後、重量平均分子量３万以上の溶融ポリマーを冷却固化し、取り出し、汎用の押出機を用いて、冷却固化させたポリマーにトリアリールホスファイト化合物を添加し再溶融押出後、冷却固化し、所望の固形物、例えば、ペレット状、板状、フィルム状等の固形物にする方法、（Ｅ）（Ｃ）に加えて固相重合を実施する方法等いずれの方法等が挙げられる。
【００２４】
以下にグリコール酸共重合体の製造方法の一例について説明する。
原料水溶液を脱水濃縮する工程では、脱水濃縮の条件は制限されるものではないが、例えば、窒素等の不活性ガス雰囲気下、不活性ガス流通下又は減圧下において、温度１００〜１５０℃、好ましくは１００〜１３０℃の範囲、減圧度１３．３〜１０１．３ｋＰａの範囲で、それぞれ多段階に変化させて実施する。このとき、（Ｂ）法のように、原料水溶液中に金属アルコキシドが添加されている場合、脱水濃縮及びこれに続く溶融重縮合工程において金属アルコキシドの加水分解反応を同時に行うことができる。
【００２５】
溶融重縮合工程では、例えば、窒素等の不活性ガス雰囲気下、不活性ガス流通下又は減圧下において、反応温度１３０℃〜２２０℃の範囲で多段階に変化させて重縮合を行うことが好ましく、より好ましくは１５０℃〜２００℃の範囲である。重縮合温度が１３０℃未満の場合には、反応速度が遅く、非効率的であり、また高分子量のポリマーが得られないことがある。逆に ２２０℃を越える温度の場合には、ポリマーの着色及び分解、又は環状２量体等の副生物の留出が多くなる。
【００２６】
本発明における溶融重縮合反応時の減圧度は、通常、１３．３Ｐａ〜６．７ｋＰａ、好ましくは６６．７Ｐａ〜６．０ｋＰａ、最も好ましくは０．４〜５．３ｋＰａの範囲で、多段階に変化させて重縮合を行う。６．７ｋＰａを越える圧力の場合には、重縮合時に発生する水を効率よく除去できない場合があり、１３．３Ｐａ未満の場合には、収率が低下する場合がある。
本発明における溶融重縮合反応の時間は２〜２０時間、好ましくは４〜１５時間の範囲である。２０時間を超えて実施する場合には、ポリマーの着色が生じやすくなる。
【００２７】
本発明においては、比較的高い蒸発比表面積が確保できる溶融重合反応装置を利用することにより、溶融重合単独でも高い分子量を有するグリコール酸共重合体を製造することができる。例えば、二軸横型高粘度反応機、塔内にワイヤーや金網等の溶融ポリマー支持体をその構造として保有する高比表面積重合装置を利用する方法等が挙げられる。
溶融重縮合によって製造したポリマーをプレポリマーとして、引き続き固相重合を実施し、着色も少なく、更に高分子量のグリコール酸共重合体を得ることもできる。プレポリマーとは、溶融重縮合により得られた生成物を意味するものであり、これを固相重合に供するまでに冷却固化せしめ、粒子状やペレット状に付形することができる。また、プレポリマーを結晶化させた後に固相重合に供することが好ましい。この結晶化条件を適切に選択することにより、プレポリマー粒子どうしの、固相重合時の融着・凝集を防止できるのみならず、固相重合時の重合反応速度を高めることもできる。
【００２８】
得られた重合体の付形化の方法には制限はないが、例えば、溶融状態のプレポリマーを不活性ガスや水等の液体と接触させることにより塊状物にした後、粉砕し、粒子状にする方法、溶融状態のプレポリマーを押出機に移し、ペレット化する方法等が利用できる。プレポリマーを粒子状又はペレット状に付形した粒子径としては、結晶化工程や固相重合工程における取り扱い易さや、固相重合における重合速度を考慮して設定すればよいが、例えば、平均粒径が０．１〜１０ｍｍの範囲が好ましい。
【００２９】
結晶化工程における結晶化の方法には制限は無く、公知の方法を利用できる。例えば、冷却固化したプレポリマーを気相中で加熱する方法、プレポリマーを溶解しない液体中で、結晶化温度にて加熱する方法等が挙げられる。
プレポリマーを結晶化させる条件にも制限はないが、例えば、窒素等の不活性ガス雰囲気下、不活性ガス流通下又は減圧下において、結晶化処理温度として、プレポリマーのガラス転移温度以上融点未満の範囲、結晶化時間１０分〜３６０分の範囲が用いられる。
【００３０】
結晶化したプレポリマーは、引き続き固相重合によって高分子量化を行う。 固相重合工程では、反応温度は、通常、結晶化プレポリマーのガラス転移温度以上、融解ピーク温度未満の範囲で実施することができる。
本発明の固相重合は、窒素等の不活性ガス雰囲気下、又は減圧下、更には加圧下で行うこともできる。反応系内の減圧度や反応系内の圧力は、充分に高い重量分子量を有するグリコール酸共重合体が得られる範囲であれば制限されない。
【００３１】
本発明の固相重合で使用する不活性ガス、すなわち、反応系に流通させるガスの具体例としては、窒素ガス、ヘリウムガス、アルゴンガス、キセノンガス、クリプトン ガス等が挙げられる。流通させる不活性ガスに含まれる水分量は、できるだけ低く、実質的に無水状態のガスであることが好ましい。 含水量が多いと固相重合反応で生成した水が効率よく除去できないために重合速度が遅くなる。この場合、ガスをモレキュラーシーブ類やイオン交換樹脂類等を充填した層に通すことにより脱水して使用することができる。流通ガスの含水量を露点で示すと、ガスの露点は−２０℃以下、好ましくは−４０℃以下である。
【００３２】
固相重合反応の時間は５〜２００時間、好ましくは１０〜１２０時間の範囲である。
本発明のグリコール酸共重合体には、本発明の目的を損なわない範囲で、必要に応じて、フェノール系酸化防止剤、チオエーテル系酸化防止剤、紫外線防止剤、ヒンダードアミン系光安定剤、ステアリン酸カルシウム等の脂肪酸金属塩、核剤、可塑剤、他の脂肪族ポリエステル及びその前駆体等を添加することができる。
【００３３】
【発明の実施の形態】
以下、本発明を実施例により具体的に説明するが、本発明はこれらの実施例に限定されるものではない。
本発明の各特性値は以下の方法により測定する。
（１）重量平均分子量
東ソ社製ゲルパーミエーションクロマトグラフィー（ＧＰＣ）分析装置８０２０ＧＰＣシステムを用い、以下の条件で求める。使用する溶媒として、予め、８０ｍＭのトリフルオロ酢酸ナトリウムを溶解したヘキサフルオロイソプロパノール（ＨＦＩＰ）を調製しておく。より具体的には、例えば、ＨＦＩＰ１０００ｇに対してトリフルオロ酢酸ナトリウムを６．４８ｇ溶解し調製する。
【００３４】
評価用ポリマー試料溶液には、試料２０ｍｇを精秤した後、上記トリフルオロ酢酸ナトリウム含有ＨＦＩＰ３ｇに溶解し、その後、０．２ミクロンのフィルターにて濾過したものを用いる。
測定条件は、カラム温度４０℃、留出速度１ｍｌ／分で実施し、使用するカラム構成としては、ガードカラムとして、ＴｓｋｇｕａｒｄｃｏｌｕｍｎＨＨＲ−Ｌ（登録商標）を使用し、Ｔｓｋｇｅｌ（登録商標）Ｇ５０００ＨＨＲ及びＴｓｋｇｅｌ（登録商標）Ｇ３０００ＨＨＲ（いずれも東ソ社製）からなるものを使用する。
測定値は、予め、ＰＭＭＡ標準物質を用い、ＲＩ検出器による、溶出時間と分子量との関係を示す検量線を作成しておき、評価用ポリマー試料溶液測定時の溶出曲線より重量平均分子量を求めた値である。
検量線作成に際し、ＰＭＭＡ標準物質として、分子量が１，５７７、０００、６８５，０００、３３３，０００、１００，２５０、６２，６００、２４，３００、１２，７００、４，７００、１，６８０、及び１，１４０のもの（いずれもＰｏｌｙｍｅｒ Ｌａｂｏｒａｔｏｒｉｅｓ社製）を用いる。
【００３５】
（２）重合ポリマーの着色度
上記の方法にて重量平均分子量を求める際に、検出器として波長３５０ｎｍに設定したＵＶ検出器ＵＶ８０２０（東ソ社製）を接続し、その際、検出される全カウント数をもって評価する。カウント数が５０未満の場合、得られたポリマーは目視で白色〜淡黄色に相当し、カウント数が５０〜１００の範囲の場合は目視で黄色に相当し、カウント数が１００を越える場合には、得られるポリマーは目視で褐色〜黒褐色に相当する値である。
（３）グリコール酸共重合体中のグリコール酸単位の含有量
試料７０ｍｇを精秤し、ｄ化トリフルオロ酢酸１ｃｃに溶解し、基準物質としてＴＭＳを用い、１Ｈ−ＮＭＲにて測定する。
【００３６】
（４）再溶融時の熱安定性評価
重合により得られたポリマーを、予め、真空下８０℃で６時間乾燥しておく。予め、窒素置換されたフラスコに所定量のポリマーを窒素気流下にて投入し、攪拌しながら２３０℃に加熱し、溶融させ、溶融した５分後にサンプリングする。重合ポリマーの重量平均分子量及び着色度の評価と同様に上記記載の方法にしたがい、その重量平均分子量及び着色度を評価する。
着色度変化率は、この評価により得られた着色度を、加熱前着色度で除した値を百分率で表した値である。
【００３７】
【実施例１】
攪拌装置及び窒素導入管を備えた１００ｃｃ反応容器に、高純度グリコール酸（６５質量％水溶液；Ｄｕ Ｐｏｎｔ（株）社製グリピア７０（登録商標））及びＬ−乳酸（９０質量％水溶液；和光純薬（株）社製）をそれぞれ９３ｇ及び１１ｇとゲルマニウムテトライソプロポキシドをグリコール酸及び乳酸の合計量１ｇ当たり、０．００３ｍｍｏｌを仕込み、窒素置換を行った。次いで、窒素気流下、常圧、攪拌下にて１３０℃まで昇温し、原料水溶液の濃縮と同時にゲルマニウムテトラｉｓｏ−プロポキシドの加水分解反応を１時間行った。その際、留出物をトラップし、分析した結果、ゲルマニウムテトラｉｓｏ−プロポキシド１ｍｏｌに対して、３．９５ｍｏｌに相当するイソプロパノールを検出した。添加したゲルマニウムテトラｉｓｏ−プロポキシドはほぼ完全に加水分解されているといえる。
【００３８】
その後、常圧のまま、温度を１５０℃に上げ、６０分間保持し、濃縮を完結させた。更に、減圧を開始し、２７ｋＰａにて２０分、更に６．７ｋＰａにて２０分、更に０．４ｋＰａにて２０分保持し、反応を継続したのち、温度を２００℃に昇温させ、４時間重縮合反応を継続させた。
得られたグリコール酸共重合体は、重量平均分子量が２２０００であった。溶融状態のプレポリマーを冷却固化させた後取り出し、加熱された面ヒーターとその内部に内径６５ｍｍ、有効長さ１２０ｍｍのガラスチューブを有する横型回転式ガラスチューブオーブン型反応器（柴田化学（株）製ＧＴＯ−３５０ＲＧ）に得られた重合物を１５ｇ投入し、再溶融させ、回転数５ｒｐｍにて、重合時の圧力が０．４ｋＰａ、重合温度が２００℃の条件にて更に８時間重合を継続させた。その後、トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトを０．００３ｍｍｏｌ添加し、１５分反応を継続し、生成物を冷却固化させ、取り出した。得られたグリコール酸共重合体中のグリコール酸単位含有量は８８ｍｏｌ％であった。
【００３９】
得られたポリマーの重量平均分子量は１３９，０００、ポリマーの着色度は１７であった。得られたポリマーの再溶融時の熱安定性を評価した結果、重量平均分子量が１１２，０００、ポリマーの着色度変化率は１５９％、着色度は２７であった。
重合条件、製造された重合体の特性及び熱安定性評価結果を、以下の実施例及び比較例の結果と共に表１に示す。
【００４０】
【比較例１】
トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトを添加しない以外は実施例１と同様に重合し、得られたポリマーを用いて溶融安定性を評価した。 得られたポリマーの重量平均分子量は１２９，０００、ポリマーの着色度は１７であった。得られたポリマーの再溶融時の熱安定性を評価した結果、重量平均分子量が７４，０００、ポリマーのポリマーの着色度変化率は７４１％、着色度は１２６であった。
【００４１】
【比較例２】
トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトを添加する時期として、実施例１と同様に、１００ｃｃ反応容器にて２００℃にて４時間重縮合して重量平均分子量が２２０００に達した時点で添加した。添加後、更に１５分間重縮合を継続させる以外は実施例１と同様に重合を行い、得られたポリマーの溶融安定性を評価した。
得られたポリマーの重量平均分子量は４９，０００、ポリマーの着色度は３２であった。得られたポリマーの再溶融時の熱安定性を評価した結果、重量平均分子量が３４，０００、ポリマーのポリマーの着色度変化率は１７５％、着色度は５６であった。
このように、重合初期にトリアリールホスファイトを添加した場合には、重合度の上昇が著しく遅くなり、より高分子量のグリコール酸共重合体を製造しようとする場合においては、好ましくなく実用的ではない。
【００４２】
【実施例２】
トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトに変えて亜リン酸トリフェニルを使用した以外は実施例１と同様に重合し、得られたポリマーを用いて溶融安定性を評価した。
【００４３】
【比較例３】
実施例１において使用する重縮合触媒として三酸化アンチモンを使用した以外は実施例１と同様に重合した。得られたポリマーは、重量平均分子量が７５，０００、ポリマーの着色度は２３４と高かった。
このように、ポリエステルの重合において汎用に利用される三酸化アンチモンを使用した場合には、それなりの重縮合触媒性能が認められたが、得られるポリマーの着色が著しく、実用には耐えないものであった。
【００４４】
【実施例３】
実施例１で得られたプレポリマー０．５ｇを、予め、１３０℃にて５時間結晶化させたのち、ガラスウールを充填したガラスＵ管内に仕込んだ。更に上部にもガラスウールを充填した後、固相重合温度１７０℃にて、窒素ガス流量として０．２ＮＬ／分にて１０時間固相重合を実施した。
【００４５】
【実施例４〜８】
ゲルマニウムテトラｉｓｏ−プロポキシドに変えて、表１に示すようにそれぞれ、マグネシウムエトキシド、鉄トリエトキシド、アンチモントリｉｓｏ−プロポキシド、錫エトキシド、ハフニウムテトラｔｅｒｔ−ブトキシドに変更し、更に亜リン酸トリフェニルの添加量を表１に示すように変更した以外は実施例２と同様に重合を行い、溶融安定性の評価を実施した。
【００４６】
【実施例９及び１０】
ゲルマニウムテトラｉｓｏ−プロポキシドに替えて、それぞれ、ランタントリｉｓｏ−プロポキシド及びサマリウムトリｉｓｏ−プロポキシドを用い、更にトリアリールホスファイト化合物として、トリスノリルフェニルホスファイトに変更した以外は実施例１と同様に重合を行った。ランタントリｉｓｏ−プロポキシド及びサマリウムトリｉｓｏ−プロポキシドは特開平７−４８３０１号公報に記載された方法に準じて調製した。
【００４７】
【比較例４】
実施例１において使用する重縮合触媒としてチタンテトラｉｓｏ−プロポキシドを使用した以外は実施例１と同様に重合を行った。
溶融重合により得られたポリマーは、重量平均分子量が７５，０００、ポリマーの着色度の指標であるＵＶ検出器による全カウント数は２５６であった。
本発明の請求の範囲記載以外の金属アルコキシドの代表例であるチタンテトラｉｓｏ−プロポキシドを使用した場合には、それなりの重縮合触媒性能が認められたが、得られるポリマーの着色が著しく、実用には耐えないものであった。
【００４８】
【比較例５】
トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトに替えてモノステアリルアシッドホスフェートを使用した以外は実施例１と同様に重合し、得られたポリマーを用いて溶融安定性を評価した。
【００４９】
【比較例６】
トリス（２，４−ジｔｅｒｔ−ブチルフェニル）ホスファイトに替えて２，２−メチレンビス（４，６−ジｔｅｒｔ−ブチルフェニル）オクチルホスファイトを使用した以外は実施例１と同様に重合し、得られたポリマーを用いて溶融安定性を評価した。
【００５０】
【表１】
【発明の効果】
本発明によれば、比較的高い溶融温度で再溶融し、成形加工に供する場合においても着色が少ない、高分子量で高品質のポリグリコール酸共重合体を製造することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing a glycolic acid copolymer. More specifically, the present invention relates to a method for producing a glycolic acid copolymer which is less likely to be colored during melt processing.
[0002]
[Prior art]
Aliphatic polyesters produced from hydroxycarboxylic acids typified by polylactic acid, polyglycolic acid or copolymers thereof have attracted attention as biodegradable polymers, for example, medical materials such as sutures, pharmaceuticals, and agricultural chemicals. It is used in various fields, such as a sustained-release material such as fertilizer. In particular, polyglycolic acid and glycolic acid copolymers mainly composed of glycolic acid structural units have the feature of being excellent in gas barrier properties, and many proposals have been made for use in packaging materials such as films.
[0003]
Conventionally, as a method for producing these polymers, lactic acid and glycolic acid are once polycondensed to form a prepolymer, and then lactide and / or glycolide are produced by depolymerization, and ring-opening polymerization is performed using these to obtain polylactide. And polyglycolide. According to this method, although a polymer having a high molecular weight can be obtained, a large number of steps are required, and a large amount of labor is required to obtain lactide and glycolide, which is not economical.
[0004]
The present inventors have previously used a hydrolysis product obtained by hydrolyzing a specific metal alkoxide in the presence of glycolic acid as a catalyst, by directly polycondensing a raw material such as glycolic acid, The inventors have found that a high-quality glycolic acid copolymer having a high molecular weight and less coloring during polymerization can be obtained efficiently, and applied for a patent (Japanese Patent Application No. 2001-93676).
However, a glycolic acid copolymer containing a large number of glycolic acid structural units has a relatively high melting point, so that the temperature during melt processing is high, and when subjected to molding or the like, the coloration of the polymer is remarkable or significant. A decrease in molecular weight can often be observed.
[0005]
As a method for producing polylactic acid which solves such a problem, Japanese Patent Application Laid-Open No. 9-151243 discloses a method in which lactide is subjected to ring-opening polymerization using a metal catalyst such as tin at the latter half of polymerization or at the end of polymerization. There has been proposed a method for producing a high-molecular-weight polylactic acid having excellent heat stability, particularly excellent molecular weight retention by adding a system ester. However, this publication does not disclose any case of producing polyglycolic acid and / or a glycolic acid copolymer using glycolic acid as a starting material. When the present inventors produced a glycolic acid copolymer by a polycondensation reaction, as a result of attempting this, a slight improvement in the retention of the molecular weight at the melting point or higher, for example, at 230 ° C. was observed. However, no satisfactory effect was obtained with respect to the coloring suppression effect.
In view of such circumstances, there is a strong demand for a technique that can produce a polyglycolic acid and / or glycolic acid copolymer having little coloration during polymerization and re-melt processing and having a high molecular weight.
[0006]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to provide a glycolic acid copolymer capable of maintaining high quality with little coloring even in melt processing at a relatively high temperature and a method for producing the same.
[0007]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to solve the above-described problems, and as a result, carried out polymerization in the presence of a specific polycondensation catalyst, and at a stage where the molecular weight has reached a specific molecular weight or more, a specific phosphorus-containing compound. By adding, not only the coloring during polymerization can be suppressed, but also when the obtained polymer is melt-processed at a temperature higher than the polymerization temperature, a glycolic acid copolymer with less coloring of the polymer can be obtained. I found that.
[0008]
That is, the present invention is as follows.
(1) The weight average molecular weight is 50,000 or more, contains 75 mol% or more of glycolic acid units, and the degree of change in coloring degree after heating and melting at 230 ° C. for 5 minutes is 110 to 300 with respect to the coloring degree before heating. % Glycolic acid copolymer.
(2) A method for producing a glycolic acid copolymer containing at least 75 mol% of glycolic acid units by polycondensing a raw material containing at least glycolic acid, wherein the weight average molecular weight is 3 in the course of the polycondensation reaction. The method for producing a glycolic acid copolymer according to (1), wherein a triaryl phosphite compound is added at a stage when the number reaches 10,000 or more.
(3) a hydrolyzate obtained by hydrolyzing at least one metal alkoxide selected from the group consisting of magnesium, iron, hafnium, germanium, antimony, tin, lanthanum and samarium in the presence of a hydroxycarboxylic acid; The method for producing a glycolic acid copolymer according to (2), which is used as a polycondensation catalyst.
[0009]
Hereinafter, the present invention will be described in detail.
In the present invention, the content of glycolic acid units contained in the glycolic acid copolymer is 75 mol% or more, preferably 75 mol% or more and 99 mol% or less, more preferably 80 mol% or more and 95 mol% or less. , Most preferably in the range from 82 mol% to 90 mol%. When the content of the glycolic acid unit is less than 75 mol%, mechanical properties such as strength and elastic modulus, thermal properties such as softening temperature, and gas barrier properties of the obtained copolymer deteriorate. When the content of the glycolic acid unit exceeds 99 mol%, the thermal stability of the copolymer is not sufficient, and the copolymer tends to be thermally decomposed at the time of melt molding to lower the coloring and the molecular weight.
[0010]
Examples of the copolymerization component other than the glycolic acid unit include other hydroxycarboxylic acids, dicarboxylic acids, diols, trivalent or higher polyvalent compounds and polysaccharides, and those copolymerizable with glycolic acid. However, it is not limited to these.
Examples of other hydroxycarboxylic acids include L-lactic acid, D-lactic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid and 6-hydroxycaproic acid, 12-hydroxystearin Acids, 16-hydroxyhexadecanoic acid and the like.
[0011]
Examples of dicarboxylic acids include, for example, aliphatic dicarboxylic acids such as succinic acid, oxalic acid, malonic acid, glutanic acid, adipic acid, pimelic acid, and diglycolic acid.
Examples of diols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, and Diethylene glycol and the like.
[0012]
Examples of the trifunctional or higher polyfunctional compound include glycerin, trimethylolpropane, pentaerythritol, malic acid, trimellitic acid, trimesic acid, pyromellitic acid, tricarballylic acid, and gallic acid.
Examples of polysaccharides include, for example, cellulose, cellulose nitrate, cellulose acetate, methyl cellulose, ethyl cellulose, CMC (carboxymethyl cellulose), hemicellulose, starch, amylopectin, dextrin, dextran, glycogen, pectin, chitin, chitosan and the like, and mixtures thereof. And their derivatives.
[0013]
Preferred examples of the copolymer component include D-lactic acid and L-lactic acid. A more preferred example is L-lactic acid, more preferably L-lactic acid having an optical purity of 95% or more, most preferably 98% or more, produced by a fermentation method. If desired, an oligomer containing a glycolic acid unit can be used together with the above copolymerization component.
These glycolic acid and copolymer components can be used for the production of the glycolic acid copolymer of the present invention either in a solid form or in the form of an aqueous solution.
[0014]
The weight average molecular weight of the glycolic acid copolymer of the present invention is 50,000 or more, and the degree of change in the degree of coloring after being heated and melted at 230 ° C. for 5 minutes is 110 to 300% with respect to the degree of coloring before heating.
The weight average molecular weight used in the present invention, the degree of coloration of the glycolic acid copolymer, and its rate of change can be determined by the measurement methods described later.
When the weight average molecular weight of the glycolic acid copolymer is less than 50,000, the melt viscosity does not have to be sufficient for molding, and the obtained molded product does not have sufficient strength.
[0015]
The coloring degree change rate used in the present invention is a value obtained by dividing the coloring degree after heating and melting the glycolic acid copolymer at 230 ° C. for 5 minutes by the coloring degree before heating and expressing the value in percentage. In the present invention, it is important that the degree of change in the degree of coloring be in the range of 110 to 300%, preferably 110 to 250%, and most preferably 110 to 200%. If the degree of change in the degree of coloring exceeds 300%, the quality as a processed product is greatly reduced.
In the production of the glycolic acid copolymer of the present invention, as a catalyst, magnesium, iron, hafnium, germanium, antimony, lanthanum, and at least one metal alkoxide selected from the group consisting of samarium, in the presence of hydroxycarboxylic acid, It is preferable to use a hydrolyzate obtained by hydrolysis.
[0016]
The metal alkoxide is a compound in which at least one bond between the oxygen atom to which the alkyl group is bonded and the metal atom is present in the molecule. Examples of a compound in which an alkyl group is bonded to an oxygen atom include methoxide, ethoxide, n-propoxide, iso-propoxide, n-butoxide, iso-butoxide, tert-butoxide, n-hexyl alkoxide, 2-hexyl alkoxide and the like. Monovalent alkoxides, divalent alkoxides such as ethylene glycoloxide, 1,2-propane dialkoxide, 1,3-propane alkoxide and 1,4-butane dialkoxide, and tetravalent alkoxides such as pentaerythritol Is mentioned. These can be used alone or in combination of two or more.
[0017]
Examples of the bond between the oxygen atom to which the alkyl group is bonded and the metal atom include magnesium ethoxide, iron triethoxide, hafnium tetratert-butoxide, germanium tetraethoxide, germanium tetraiso-propoxide, antimony triiso-ethoxide, and lanthanum. Tri-iso-propoxide, samarium iso-propoxide and the like can be mentioned.
Although the detailed chemical structure of the hydrolyzate of the metal alkoxide is not clear, the metal alkoxide removes the alcohol, the hydroxide {M- (OH) X}, the condensation polymerization product of the metal alkoxide {-M- OM- {, an alcohol exchange reaction with glycolic acid {M- (OCH2COOH) X}, a metal salt reacted with glycolic acid {M- (OCOCH2OH) X}, and a coordinated product of glycolic acid. It is presumed to include multiple chemical structures.
[0018]
The method for obtaining the hydrolyzate of the metal alkoxide is not limited. For example, (a) before the polycondensation reaction, the method is previously selected from the group consisting of magnesium, iron, hafnium, germanium, antimony, lanthanum and samarium. A method of preparing a hydrolyzate by hydrolyzing at least one metal alkoxide in the presence of an aqueous solution containing glycolic acid and a sufficient amount of water; (b) magnesium, iron, hafnium, germanium, antimony, lanthanum And at least one metal alkoxide selected from the group consisting of samarium and samarium is added to an aqueous solution of the polymerization raw material containing at least 3% by weight of water and glycolic acid, and during the step of performing dehydration concentration and polycondensation, In which a hydrolyzate is formed. From the viewpoint that the process can be simplified, the method of the method (b) of forming a hydrolyzate of a metal alkoxide together with dehydration concentration and polycondensation in a polymerization system is preferable.
[0019]
The amount of the metal alkoxide hydrolyzate used as the polycondensation catalyst for the glycolic acid copolymer is usually 1 × 10 4 -7 ~ 1 × 10 -2 Mole, preferably 3 × 10 -7 ~ 1 × 10 -3 Range of moles. 1 × 10 -7 If the amount is less than 1 mol, it is difficult to increase the rate of polycondensation, and the addition amount is 1 × 10 -2 If the molar ratio is exceeded, side reactions such as coloring of the polymer may increase, and no increase in molecular weight may be observed.
[0020]
In the present invention, examples of the triaryl phosphite compound added in the polymerization step include triphenyl phosphite, tris (2-tert-butylphenyl) phosphite, and tris (2,4-ditert-butylphenyl) phosphite. Phytite, tris (2,5-ditert-butylphenyl) phosphite, tris (2-tert-butyl-4-methylphenyl) phosphite, tris (2-tert-butyl-5-methylphenyl) phosphite, tris (2-tert-butyl-4,6-dimethylphenyl) phosphite, trisnonylphenyl phosphite, tris (mono and dinonylphenyl) phosphite, and the like. Preferably, triphenyl phosphite, tris (2-tert-butylphenyl) phosphite, tris (2,4-ditert-butylphenyl) phosphite, and tris (2,5-ditert-butylphenyl) phosphite Fight.
[0021]
The amount of the triaryl phosphite compound is not limited, but is usually 0.1 to 10 mol, preferably 0.3 to 3 mol, more preferably 0 to 1 mol per 1 mol of the catalyst metal atom used in the polymerization. It is used in the range of 0.5 to 2 mol. If the amount is less than 0.1 mol, the coloring during melting may not be sufficiently eliminated. If the amount exceeds 10 mol, the molecular weight does not increase and the coloring is reversed when the polymerization is further continued. May be significant.
[0022]
In the present invention, the time at which the triaryl phosphite compound is added during the production of the glycolic acid copolymer is preferably such that the weight average molecular weight has reached 30,000 or more, more preferably 50,000 or more, by the polymerization reaction. It is. If the compound is added at a stage where the weight average molecular weight is less than 30,000, the effect of suppressing coloring intended by the present invention is not exhibited. Further, the subsequent polymerization rate is reduced, and a glycolic acid copolymer having a high molecular weight cannot be obtained.
[0023]
The method for producing the glycolic acid copolymer in the present invention is not limited. For example, (A) a catalyst prepared by preliminarily hydrolyzing a metal alkoxide in the presence of a hydroxycarboxylic acid at any time from a dehydration concentration step to a subsequent melt polycondensation step of a raw material aqueous solution containing water and glycolic acid. , Melt polycondensation, and when the weight average molecular weight reaches 30,000 or more, a triaryl phosphite compound is added to produce a glycolic acid copolymer, (B) water and hydroxycarboxylic acid After the metal alkoxide is added to the aqueous solution of the polymerization raw material containing the acid, a dehydration concentration step and a melt polycondensation step are carried out to form a catalyst in the polymerization system, melt polycondensation is performed, and the weight average molecular weight is 30,000. A method for producing a glycolic acid copolymer by adding a triaryl phosphite compound at the stage reached above, wherein (C) (A) or (B) After the completion of melt polycondensation without adding a triaryl phosphite, in a step of granulating a molten polymer having a weight average molecular weight of 30,000 or more into pellets, a method of adding a triaryl phosphite compound, (D) In (A) or (B), after completion of the melt polycondensation without adding a triaryl phosphite, a molten polymer having a weight average molecular weight of 30,000 or more is solidified by cooling, taken out, and used with a general-purpose extruder. A method of adding a triaryl phosphite compound to the cooled and solidified polymer, re-melting and extruding, and then solidifying by cooling to obtain a desired solid, for example, a solid such as a pellet, a plate or a film; ) In addition to (C), any method such as a method of carrying out solid phase polymerization can be mentioned.
[0024]
Hereinafter, an example of a method for producing a glycolic acid copolymer will be described.
In the step of dehydrating and concentrating the raw material aqueous solution, the conditions for dehydrating and concentrating are not limited. For example, under an inert gas atmosphere such as nitrogen, under an inert gas flow or under reduced pressure, a temperature of 100 to 150 ° C., preferably Is carried out in a range of 100 to 130 ° C. and a degree of decompression of 13.3 to 101.3 kPa in each of multiple steps. At this time, when the metal alkoxide is added to the raw material aqueous solution as in the method (B), the hydrolysis reaction of the metal alkoxide can be simultaneously performed in the dehydration concentration and the subsequent melt polycondensation step.
[0025]
In the melt polycondensation step, for example, under an inert gas atmosphere such as nitrogen, under an inert gas flow or under reduced pressure, it is preferable to perform polycondensation by changing the reaction temperature in a range of 130 ° C. to 220 ° C. in multiple stages. And more preferably in the range of 150 ° C to 200 ° C. When the polycondensation temperature is lower than 130 ° C., the reaction rate is slow and inefficient, and a high molecular weight polymer may not be obtained. On the other hand, when the temperature is higher than 220 ° C., coloring and decomposition of the polymer or distilling of by-products such as cyclic dimers increase.
[0026]
The degree of pressure reduction during the melt polycondensation reaction in the present invention is usually in the range of 13.3 Pa to 6.7 kPa, preferably 66.7 Pa to 6.0 kPa, and most preferably 0.4 to 5.3 kPa. The polycondensation is carried out with a change. If the pressure exceeds 6.7 kPa, water generated during polycondensation may not be efficiently removed. If the pressure is less than 13.3 Pa, the yield may decrease.
The time of the melt polycondensation reaction in the present invention is in the range of 2 to 20 hours, preferably 4 to 15 hours. When the treatment is performed for more than 20 hours, coloring of the polymer is likely to occur.
[0027]
In the present invention, a glycolic acid copolymer having a high molecular weight can be produced by melt polymerization alone by using a melt polymerization reaction apparatus capable of securing a relatively high evaporation specific surface area. For example, a biaxial horizontal high-viscosity reactor, a method using a high specific surface area polymerization apparatus having a molten polymer support such as a wire or a wire mesh in the tower as its structure, and the like can be mentioned.
Using the polymer produced by melt polycondensation as a prepolymer, solid phase polymerization is subsequently carried out to obtain a glycolic acid copolymer having less coloring and a higher molecular weight. The prepolymer means a product obtained by melt polycondensation, which can be cooled and solidified before being subjected to solid-state polymerization, and can be shaped into particles or pellets. Further, it is preferable to subject the prepolymer to crystallization before subjecting it to solid phase polymerization. By appropriately selecting the crystallization conditions, not only the fusion and agglomeration of the prepolymer particles during the solid phase polymerization can be prevented, but also the polymerization reaction rate during the solid phase polymerization can be increased.
[0028]
There is no limitation on the method of shaping the obtained polymer.For example, the prepolymer in a molten state is made into a lump by contacting with a liquid such as an inert gas or water, then pulverized, and then pulverized. And a method in which the prepolymer in a molten state is transferred to an extruder and pelletized. The particle diameter of the prepolymer formed into particles or pellets may be set in consideration of the ease of handling in the crystallization step or the solid-state polymerization step, or the polymerization rate in the solid-state polymerization. The diameter is preferably in the range of 0.1 to 10 mm.
[0029]
The crystallization method in the crystallization step is not limited, and a known method can be used. For example, a method of heating a cooled and solidified prepolymer in a gas phase, a method of heating at a crystallization temperature in a liquid in which the prepolymer is not dissolved, and the like can be given.
The conditions for crystallizing the prepolymer are not limited, but, for example, under an inert gas atmosphere such as nitrogen, under an inert gas flow or under reduced pressure, as a crystallization treatment temperature, the glass transition temperature of the prepolymer or higher and lower than the melting point. And a crystallization time of 10 minutes to 360 minutes.
[0030]
The crystallized prepolymer is subsequently subjected to solid-state polymerization to increase the molecular weight. In the solid phase polymerization step, the reaction can be usually performed at a temperature equal to or higher than the glass transition temperature of the crystallized prepolymer and lower than the melting peak temperature.
The solid phase polymerization of the present invention can be carried out under an atmosphere of an inert gas such as nitrogen, or under reduced pressure, and further under pressure. The degree of pressure reduction in the reaction system and the pressure in the reaction system are not limited as long as a glycolic acid copolymer having a sufficiently high weight molecular weight can be obtained.
[0031]
Specific examples of the inert gas used in the solid-phase polymerization of the present invention, that is, the gas passed through the reaction system include nitrogen gas, helium gas, argon gas, xenon gas, and krypton gas. The amount of water contained in the inert gas to be circulated is preferably as low as possible and substantially anhydrous. If the water content is large, the polymerization rate becomes slow because water generated in the solid-state polymerization reaction cannot be efficiently removed. In this case, the gas can be dehydrated and used by passing the gas through a layer filled with molecular sieves, ion exchange resins, or the like. When the water content of the flowing gas is indicated by the dew point, the dew point of the gas is -20 ° C or lower, preferably -40 ° C or lower.
[0032]
The time of the solid state polymerization reaction is in the range of 5 to 200 hours, preferably 10 to 120 hours.
The glycolic acid copolymer of the present invention may contain a phenolic antioxidant, a thioether-based antioxidant, an ultraviolet ray inhibitor, a hindered amine light stabilizer, and calcium stearate, as long as the object of the present invention is not impaired. And the like, a nucleating agent, a plasticizer, other aliphatic polyesters and precursors thereof.
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.
Each characteristic value of the present invention is measured by the following method.
(1) Weight average molecular weight
It is obtained under the following conditions using a gel permeation chromatography (GPC) analyzer 8020 GPC system manufactured by Tosoh Corporation. Hexafluoroisopropanol (HFIP) in which 80 mM sodium trifluoroacetate is dissolved is prepared in advance as a solvent to be used. More specifically, for example, it is prepared by dissolving 6.48 g of sodium trifluoroacetate in 1000 g of HFIP.
[0034]
As the polymer sample solution for evaluation, a sample obtained by precisely weighing 20 mg of a sample, dissolving the sample in 3 g of HFIP containing sodium trifluoroacetate, and then filtering through a 0.2-micron filter is used.
The measurement was carried out at a column temperature of 40 ° C. and a distillation rate of 1 ml / min. The column configuration to be used was a Tsguardcolumn HHR-L (registered trademark) as a guard column. (Registered trademark) G3000HHR (all manufactured by Tosoh Corporation) is used.
For the measured values, a calibration curve showing the relationship between the elution time and the molecular weight was prepared using a PMMA standard material and the RI detector in advance, and the weight average molecular weight was determined from the elution curve when the polymer sample solution for evaluation was measured. Value.
In preparing the calibration curve, the molecular weights of PMMA standard substances were 1,577,000, 685,000, 333,000, 100,250, 62,600, 24,300, 12,700, 4,700, 1,680, And 1,140 (both manufactured by Polymer Laboratories) are used.
[0035]
(2) Coloring degree of polymer
When the weight average molecular weight is determined by the above method, a UV detector UV8020 (manufactured by Tosoh Corporation) set to a wavelength of 350 nm is connected as a detector, and the evaluation is performed based on the total number of detected counts. When the count number is less than 50, the obtained polymer is visually equivalent to white to pale yellow, and when the count number is in the range of 50 to 100, it is visually equivalent to yellow, and when the count number exceeds 100, The obtained polymer has a value corresponding to visually brown to blackish brown.
(3) Content of glycolic acid unit in glycolic acid copolymer
A 70 mg sample is precisely weighed and dissolved in 1 cc of d-trifluoroacetic acid, and measured by 1H-NMR using TMS as a reference substance.
[0036]
(4) Evaluation of thermal stability during remelting
The polymer obtained by polymerization is previously dried at 80 ° C. for 6 hours under vacuum. A predetermined amount of a polymer is charged into a nitrogen-purged flask in advance under a nitrogen stream, heated to 230 ° C. with stirring, melted, and sampled 5 minutes after melting. The weight average molecular weight and the degree of coloring of the polymer are evaluated in the same manner as in the evaluation of the weight average molecular weight and the degree of coloring of the polymer.
The degree of change in the degree of coloring is a value obtained by dividing the degree of coloring obtained by this evaluation by the degree of coloring before heating, expressed as a percentage.
[0037]
Embodiment 1
In a 100 cc reaction vessel equipped with a stirrer and a nitrogen inlet tube, high-purity glycolic acid (65 mass% aqueous solution; Gripia 70 (registered trademark) manufactured by Du Pont Co.) and L-lactic acid (90 mass% aqueous solution; Wako Pure) 93 g and 11 g of Yakuhin Co., Ltd., respectively, and 0.003 mmol of germanium tetraisopropoxide per 1 g of the total amount of glycolic acid and lactic acid were charged and nitrogen replacement was performed. Then, the temperature was raised to 130 ° C. under a nitrogen stream at normal pressure and with stirring, and the hydrolysis of germanium tetraiso-propoxide was performed for 1 hour simultaneously with the concentration of the raw material aqueous solution. At that time, the distillate was trapped and analyzed. As a result, isopropanol equivalent to 3.95 mol was detected with respect to 1 mol of germanium tetraiso-propoxide. It can be said that the added germanium tetra-iso-propoxide is almost completely hydrolyzed.
[0038]
Thereafter, the temperature was raised to 150 ° C. while maintaining the normal pressure, and the temperature was maintained for 60 minutes to complete the concentration. Further, the pressure was reduced, the pressure was maintained at 27 kPa for 20 minutes, further maintained at 6.7 kPa for 20 minutes, and further maintained at 0.4 kPa for 20 minutes. After continuing the reaction, the temperature was increased to 200 ° C., and the temperature was increased for 4 hours. The polycondensation reaction was continued.
The obtained glycolic acid copolymer had a weight average molecular weight of 22,000. The molten prepolymer is cooled and solidified and then taken out. A horizontal rotating glass tube oven type reactor having a heated surface heater and a glass tube having an inner diameter of 65 mm and an effective length of 120 mm (manufactured by Shibata Chemical Co., Ltd.) GTO-350RG) was charged with 15 g of the obtained polymer, and was re-melted. The polymerization was continued for 8 hours at a rotation speed of 5 rpm under the conditions of a polymerization pressure of 0.4 kPa and a polymerization temperature of 200 ° C. Was. Thereafter, 0.003 mmol of tris (2,4-ditert-butylphenyl) phosphite was added, the reaction was continued for 15 minutes, and the product was cooled and solidified and taken out. The glycolic acid unit content in the obtained glycolic acid copolymer was 88 mol%.
[0039]
The weight average molecular weight of the obtained polymer was 139,000, and the coloring degree of the polymer was 17. As a result of evaluating the thermal stability of the obtained polymer at the time of remelting, the weight average molecular weight was 112,000, the degree of change in the degree of coloring of the polymer was 159%, and the degree of coloring was 27.
Table 1 shows the polymerization conditions, the properties of the produced polymer, and the results of the thermal stability evaluation, together with the results of the following Examples and Comparative Examples.
[0040]
[Comparative Example 1]
Polymerization was carried out in the same manner as in Example 1 except that tris (2,4-ditert-butylphenyl) phosphite was not added, and melt stability was evaluated using the obtained polymer. The weight average molecular weight of the obtained polymer was 129,000, and the coloring degree of the polymer was 17. As a result of evaluating the thermal stability of the obtained polymer at the time of remelting, the weight average molecular weight was 74,000, the degree of change in the degree of coloring of the polymer was 741%, and the degree of coloring was 126.
[0041]
[Comparative Example 2]
As for the timing of adding tris (2,4-ditert-butylphenyl) phosphite, similarly to Example 1, polycondensation was performed in a 100 cc reaction vessel at 200 ° C. for 4 hours to reach a weight average molecular weight of 22,000. Added at the time. After the addition, polymerization was carried out in the same manner as in Example 1 except that the polycondensation was further continued for 15 minutes, and the melt stability of the obtained polymer was evaluated.
The weight average molecular weight of the obtained polymer was 49,000, and the coloring degree of the polymer was 32. As a result of evaluating the thermal stability of the obtained polymer at the time of remelting, the weight average molecular weight was 34,000, the degree of change in the degree of coloring of the polymer was 175%, and the degree of coloring was 56.
As described above, when the triaryl phosphite is added in the initial stage of the polymerization, the increase in the degree of polymerization is significantly slowed, and when it is intended to produce a higher molecular weight glycolic acid copolymer, it is not preferable and not practical. Absent.
[0042]
Embodiment 2
Polymerization was carried out in the same manner as in Example 1 except that triphenyl phosphite was used instead of tris (2,4-ditert-butylphenyl) phosphite, and melt stability was evaluated using the obtained polymer.
[0043]
[Comparative Example 3]
Polymerization was carried out in the same manner as in Example 1 except that antimony trioxide was used as the polycondensation catalyst used in Example 1. The weight average molecular weight of the obtained polymer was 75,000, and the coloring degree of the polymer was as high as 234.
As described above, when antimony trioxide, which is widely used in the polymerization of polyester, is used, the performance of the polycondensation catalyst is recognized, but the obtained polymer is significantly colored and is unsuitable for practical use. there were.
[0044]
Embodiment 3
0.5 g of the prepolymer obtained in Example 1 was crystallized in advance at 130 ° C. for 5 hours, and then charged in a glass U tube filled with glass wool. After glass wool was further filled in the upper part, solid-state polymerization was performed at a solid-state polymerization temperature of 170 ° C. and a nitrogen gas flow rate of 0.2 NL / min for 10 hours.
[0045]
Embodiments 4 to 8
Instead of germanium tetraiso-propoxide, as shown in Table 1, magnesium ethoxide, iron triethoxide, antimony tri-iso-propoxide, tin ethoxide, and hafnium tetratert-butoxide, respectively, and further triphenyl phosphite Polymerization was carried out in the same manner as in Example 2 except that the addition amount of was changed as shown in Table 1, and the melt stability was evaluated.
[0046]
Embodiments 9 and 10
Example 1 was repeated except that lanthanum tri-iso-propoxide and samarium tri-iso-propoxide were used instead of germanium tetra-iso-propoxide, and that trisnolylphenyl phosphite was used as the triaryl phosphite compound. Polymerization was performed in the same manner. Lanthanum tri-iso-propoxide and samarium tri-iso-propoxide were prepared according to the method described in JP-A-7-48301.
[0047]
[Comparative Example 4]
Polymerization was carried out in the same manner as in Example 1 except that titanium tetraiso-propoxide was used as the polycondensation catalyst used in Example 1.
The polymer obtained by the melt polymerization had a weight average molecular weight of 75,000, and the total count by a UV detector, which is an index of the degree of coloring of the polymer, was 256.
When titanium tetraiso-propoxide, which is a typical example of a metal alkoxide other than those described in the claims of the present invention, was used, a certain degree of polycondensation catalyst performance was observed. Was unbearable.
[0048]
[Comparative Example 5]
Polymerization was carried out in the same manner as in Example 1 except that monostearyl acid phosphate was used instead of tris (2,4-ditert-butylphenyl) phosphite, and the melt stability was evaluated using the obtained polymer.
[0049]
[Comparative Example 6]
Polymerization was carried out in the same manner as in Example 1, except that 2,2-methylenebis (4,6-ditert-butylphenyl) octyl phosphite was used instead of tris (2,4-ditert-butylphenyl) phosphite. The melt stability was evaluated using the obtained polymer.
[0050]
[Table 1]
【The invention's effect】
According to the present invention, a high-molecular-weight, high-quality polyglycolic acid copolymer with little coloration can be produced even when remelted at a relatively high melting temperature and subjected to molding.
Claims (3)
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004137490A (en) * | 2002-09-24 | 2004-05-13 | Asahi Kasei Chemicals Corp | Glycolic acid copolymer and method for producing the same |
| WO2007060981A1 (en) * | 2005-11-24 | 2007-05-31 | Kureha Corporation | Method for controlling water resistance of polyglycolic acid resin |
| EP3873968A4 (en) * | 2018-10-29 | 2022-07-20 | Pujing Chemical Industry Co., Ltd | Controlled production of polyglycolic acid and glycolide |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2008101229A (en) * | 2008-01-18 | 2008-05-01 | Asahi Kasei Chemicals Corp | Glycolic acid copolymer |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2004137490A (en) * | 2002-09-24 | 2004-05-13 | Asahi Kasei Chemicals Corp | Glycolic acid copolymer and method for producing the same |
| JP4540321B2 (en) * | 2002-09-24 | 2010-09-08 | 旭化成ケミカルズ株式会社 | Glycolic acid copolymer and method for producing the same |
| WO2007060981A1 (en) * | 2005-11-24 | 2007-05-31 | Kureha Corporation | Method for controlling water resistance of polyglycolic acid resin |
| CN101316877B (en) * | 2005-11-24 | 2011-11-23 | 株式会社吴羽 | Method for controlling water resistance of polyglycolic acid resin |
| US8318837B2 (en) | 2005-11-24 | 2012-11-27 | Kureha Corporation | Method for controlling water resistance of polyglycolic acid resin |
| JP5339726B2 (en) * | 2005-11-24 | 2013-11-13 | 株式会社クレハ | Method for controlling water resistance of polyglycolic acid resin |
| EP3873968A4 (en) * | 2018-10-29 | 2022-07-20 | Pujing Chemical Industry Co., Ltd | Controlled production of polyglycolic acid and glycolide |
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