CN101054438A - Method of preparing solid state condensation viscosity enhancing polylactic acid - Google Patents
Method of preparing solid state condensation viscosity enhancing polylactic acid Download PDFInfo
- Publication number
- CN101054438A CN101054438A CNA200710039824XA CN200710039824A CN101054438A CN 101054438 A CN101054438 A CN 101054438A CN A200710039824X A CNA200710039824X A CN A200710039824XA CN 200710039824 A CN200710039824 A CN 200710039824A CN 101054438 A CN101054438 A CN 101054438A
- Authority
- CN
- China
- Prior art keywords
- solid state
- preparation
- viscosity enhancing
- polylactic acid
- state condensation
- 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.)
- Pending
Links
Classifications
-
- 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
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/02—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds
- C08G63/06—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from hydroxycarboxylic acids
- C08G63/08—Lactones or lactides
-
- 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
- C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
- C08G63/78—Preparation processes
- C08G63/80—Solid-state polycondensation
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Biological Depolymerization Polymers (AREA)
- Polyesters Or Polycarbonates (AREA)
Abstract
The invention relates to a preparing method for solid condensed adhesion polylactate, belonging to compound material technical field. The method comprises: firstly preparing polylactate prepolymer in which the nucleating agent distributes equally, then solid condensation and adhesion to the prepolymer. The method can increase the solid adhesion efficiency of the polylactate, improve the crystallization capacity of the polylactate, obtain the macromolecule polylactate with a good processing performance and mechanical property which has a complete biodegradation and can be widely used as a environment friendly general plastic.
Description
Technical field
The invention belongs to technical field of composite materials, be specifically related to a kind of preparation method of solid state condensation viscosity enhancing polylactic acid.
Background technology
Along with the progress of science and the development of society, shortage of resources and environmental pollution problems become increasingly conspicuous, and have become the global problem of people's extensive concern.Poly(lactic acid) (PLA) is a kind of polymkeric substance with good biocompatibility; it derives from renewable resources farm crop (as corn); the most outstanding advantage is a biodegradability; it can be degraded fully by the occurring in nature microorganism after using; final carbonic acid gas and the water of generating; free from environmental pollution, highly beneficial to the protection environment.
High molecular weight polylactic acid mainly is by ring-opening polymerization at present, among the patent JP56-14688, obtains the lactide dimer of lactic acid earlier, prepares high molecular weight polylactic acid through ring-opening polymerization again, and shortcoming is that cost is too high, has seriously limited practical application.
And obtain the direct polycondensation method of poly(lactic acid) from the lactic acid direct polymerization, though production cost is low, its molecular weight that can reach is lower, still can't satisfy the requirement that poly(lactic acid) is used as general-purpose plastics.Therefore need the later stage to carry out solid state condensation usually and carry out tackify, to reach the ideal molecular weight.Patent CN1594393 utilizes the method for fusion-solid state condensation to obtain high molecular weight polylactic acid.This method improves the solid state condensation reaction efficiency by adding water-retaining agent raising reaction water velocity of diffusion, but a large amount of water-retaining agents has increased cost and destroyed the pure of poly-lactic acid products.Patent CN1557853 has also obtained high molecular weight polylactic acid by lactate by fusion/solid phase polycondensation.But, because solid state condensation is by the alternately reaction of control of crystallization and two kinds of mechanism of chainpropagation, thus the slow feature limits of poly(lactic acid) crystallization velocity the raising of solid state condensation total reaction rate.And in scale operation, because lattice defects such as the spherulite size that crystallization rate causes slowly is big, structure imperfection make the poly(lactic acid) particle that caking phenomenon very easily take place in reactor.Patent CN1718607 adopts crystallization and the polymerization of method control poly(lactic acid) in the solid state condensation process that progressively heats up, prevent the particle bonding by rotatable reactor and gentle reaction conditions, yet this method is difficult to control in actual production, and significantly prolonged the reaction times, increased energy consumption.
In addition, if use as engineering plastics, shortcoming such as pure poly(lactic acid) also exists crystallization rate slow in the course of processing, and the shrinking percentage of moulded products is big, matter is crisp.
Summary of the invention
The object of the present invention is to provide a kind of preparation method of solid state condensation viscosity enhancing polylactic acid.
The preparation method of the solid state condensation viscosity enhancing polylactic acid that the present invention proposes, concrete steps are: with lactic acid or rac-Lactide is raw material, adopt ordinary method to prepare the poly(lactic acid) prepolymer, it is equal to add the nuclear agent in the process of preparation poly(lactic acid) prepolymer, adopt ordinary method that this poly(lactic acid) prepolymer is carried out solid state condensation viscosity enhancing then, promptly get desired product, wherein, the add-on of nucleator is 0.1～10wt% of raw material add-on.
Among the present invention, described nucleator be in metal oxide, inorganic non-metallic, inorganic salt, organic salt or the mixture any.
Among the present invention, described metal oxide-type nucleator TiO
2, CaO, MgO, Al
2O
3, among the ZnO any.
Among the present invention, described inorganic non-metallic class nucleator is silicon-dioxide, talcum powder or CaF
2In any.
Among the present invention, described inorganic salts nucleator is BaSO
4, Na
2CO
3, CaCl
2In any.
Among the present invention, described organic salt nucleator be contain phenyl ring alkaline metal salt (as Sodium Benzoate, Ph (COCO
2Na), p-NaO
2CC
6H
4COC
6H
4(OCH
2CH
2) 90Q (Q is a Racemic glycidol)), an alkali metal salt that contains carboxyl and sulfo group is (as (p-(NaO) C
6H
4SO
3Na), 2-chloro-benzoic acid sodium, Sodium P-Chlorobenzoate), contain the aliphatic carboxylic acid metal salt of long carbochain, its C atomicity 〉=26 are (as (C
45H
91COONa), Zinic stearas, Magnesium Stearate, montanic acid sodium (containing 29 C), low-molecular-weight acrylic acid-ethylene copolymer ionomers etc.), or can not cause any (p-NaOC in the phenol metal-salt that contains non-ionic type of degraded and hydrolysis
6H
4CHO).
The present invention is based on the conventional preparation method of poly(lactic acid) (" single stage method " and " two-step approach "), before reaction or reaction midway or reaction finish the back and add effective nucleator and prepare prepolymer, then this kind prepolymer is carried out solid state condensation viscosity enhancing, thereby improve the prepolymer crystallization rate, improve solid state condensation efficient, and obtain the poly-lactic acid in high molecular weight that crystal property improves.
Use the present invention can improve poly(lactic acid) solid stated efficient, improve the crystal property of poly(lactic acid), obtain having the poly-lactic acid in high molecular weight of good processing characteristics and mechanical property, and have fully biodegradable, can be used as a kind of eco-friendly general-purpose plastics and be widely used.
Embodiment
Following examples help understanding the present invention, but do not limit content of the present invention.
Embodiment 1
In 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, add 10Kg L-lactic acid, catalyzer and 100g (1wt%) nanometer SiO
2, progressively being warmed up to 160 ℃ from 100 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 15 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 150 ℃, continue under the condition of vacuumizing tackify reaction 12 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 176,215 poly(lactic acid).
Embodiment 2
In 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, add 10Kg L-lactic acid, catalyzer and 300g (3wt%) Al
2O
3, progressively being warmed up to 160 ℃ from 100 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 16 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 150 ℃, continue under the condition of vacuumizing tackify reaction 10 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 167,336 poly(lactic acid).
Embodiment 3
Add 10Kg L-rac-Lactide, catalyzer and 50g (0.5wt%) nano imvite in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, be warmed up to 145 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 8 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 155 ℃, continue under the condition of vacuumizing tackify reaction 10 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 266,493 poly(lactic acid).
Embodiment 4
Add 10Kg L-rac-Lactide, catalyzer and 200g (2wt%) ZnO in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, be warmed up to 150 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 6 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 155 ℃, continue under the condition of vacuumizing tackify reaction 8 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 259,289 poly(lactic acid).
Embodiment 5～7
Based on embodiment 1, the different nucleators that are to use change into successively: nano-TiO
2, talcum powder and BaSO
4, the product weight-average molecular weight that obtains at last is followed successively by 193,655,165,111 and 159,374.
Embodiment 8～10
Based on embodiment 2, the different nucleators that are to use change into successively: Zinic stearas, organo montmorillonite and Sodium Benzoate, the product weight-average molecular weight that obtains at last is followed successively by 184,733,170,579 and 168,647.
Embodiment 11～13
Based on embodiment 3, the different nucleators that are to use change into successively: nanometer SiO
2, nano-TiO
2And talcum powder, the product weight-average molecular weight that obtains at last is followed successively by 249,224,293,259 and 230,068.
Embodiment 14～16
Based on embodiment 4, the different nucleators that are to use change into successively: BaSO
4, Zinic stearas and Sodium Benzoate, the product weight-average molecular weight that obtains at last is followed successively by 211,905,278,845 and 258,337.
Embodiment 17～19
Based on embodiment 1, different is nucleator finishes to add before the granulation of back the 5th hour, the 10th hour of polycondensation and polycondensation respectively, and the product weight-average molecular weight that obtains after the last solid stated is followed successively by 164,662,160,223 and 158,964.
Embodiment 20～22
Based on embodiment 3, different is nucleator finishes to add before the granulation of back the 2nd hour, the 5th hour of polycondensation and polycondensation respectively, and the product weight-average molecular weight that obtains after the last solid stated is followed successively by 231,957,227,379 and 224,367.
Comparative Examples 1
Add 10Kg L-lactic acid and catalyzer in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, progressively be warmed up to 160 ℃ from 100 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 15 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 150 ℃, continue under the condition of vacuumizing tackify reaction 12 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 87,436 poly(lactic acid).
Comparative Examples 2
Add 10Kg L-lactic acid and catalyzer in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, progressively be warmed up to 160 ℃ from 100 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 15 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 150 ℃, continue under the condition of vacuumizing tackify reaction 25 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 145,455 poly(lactic acid).
Comparative Examples 3
Add 10Kg L-rac-Lactide and catalyzer in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, be warmed up to 145 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 8 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 155 ℃, continue under the condition of vacuumizing tackify reaction 10 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 142,372 poly(lactic acid).
Comparative Examples 4
Add 10Kg L-rac-Lactide and catalyzer in 30 liters of reactors of being furnished with thermometer, agitator and ventpipe, be warmed up to 145 ℃, vacuum tightness was less than polycondensation under the 40mmHg condition 8 hours.After product granulation, the drying, 80 ℃ of following isothermal crystals drop into the vacuum drum reactor after 2 hours in crystallizer, are heated to 155 ℃, continue under the condition of vacuumizing tackify reaction 20 hours, vacuum tightness is less than 40mmHg, obtains weight-average molecular weight at last and be 251,768 poly(lactic acid).
Claims (10)
1. the preparation method of a solid state condensation viscosity enhancing polylactic acid, it is characterized in that concrete steps are: with lactic acid or rac-Lactide is raw material, adopt ordinary method to prepare the poly(lactic acid) prepolymer, it is equal to add the nuclear agent in the process of preparation poly(lactic acid) prepolymer, adopt ordinary method that this poly(lactic acid) prepolymer is carried out solid state condensation viscosity enhancing then, promptly get desired product, wherein, the consumption of nucleator is 0.1～10wt% of raw material charging capacity.
2, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 1, it is characterized in that described nucleator be in metal oxide, inorganic non-metallic, inorganic salt, organic salt or the mixture any.
3, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 2 is characterized in that described metal oxide-type nucleator TiO
2, CaO, MgO, Al
2O
3, among the ZnO any.
4, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 2 is characterized in that described inorganic non-metallic class nucleator is silicon-dioxide, talcum powder or CaF
2In any.
5, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 2 is characterized in that described inorganic salts nucleator is BaSO
4, Na
2CO
3, CaCl
2In any.
6, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 2, it is characterized in that described organic salt nucleator is alkaline metal salt, an alkali metal salt that contains carboxyl and sulfo group that contains phenyl ring, the aliphatic carboxylic acid metal salt that contains long carbochain, its C atomicity 〉=26, or can not cause in the degraded and the phenol metal-salt that contains non-ionic type of hydrolysis any.
7, the preparation method of solid state condensation viscosity enhancing polylactic acid according to claim 2, it is characterized in that described mixture class nucleator be organo montmorillonite, mixture NA be aluminium base phosphoric acid ester mixture with during hydrotalcite combines any.
8, the method for solid state condensation viscosity enhancing polylactic acid according to claim 1, the add-on that it is characterized in that nucleator is 0.5～5wt% of raw material add-on.
9,, it is characterized in that with lactic acid for the raw material direct melt polycondensation prepares the poly(lactic acid) prepolymer, or prepare the poly(lactic acid) prepolymer for the raw material ring-opening polymerization with the rac-Lactide according to the preparation method of one of claim 1-8 described solid state condensation viscosity enhancing polylactic acid.
10, according to the preparation method of one of claim 1-9 described solid state condensation viscosity enhancing polylactic acid, it is characterized in that nucleator adding method is: the reaction at the preparation prepolymer begins preceding adding, perhaps the reaction at the preparation prepolymer adds midway, and perhaps the reaction at the preparation prepolymer finishes the back adding.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200710039824XA CN101054438A (en) | 2007-04-24 | 2007-04-24 | Method of preparing solid state condensation viscosity enhancing polylactic acid |
| PCT/CN2008/070185 WO2008128448A1 (en) | 2007-04-24 | 2008-01-25 | Polylactic acid composition and the production method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200710039824XA CN101054438A (en) | 2007-04-24 | 2007-04-24 | Method of preparing solid state condensation viscosity enhancing polylactic acid |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101054438A true CN101054438A (en) | 2007-10-17 |
Family
ID=38794506
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA200710039824XA Pending CN101054438A (en) | 2007-04-24 | 2007-04-24 | Method of preparing solid state condensation viscosity enhancing polylactic acid |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN101054438A (en) |
| WO (1) | WO2008128448A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008128448A1 (en) * | 2007-04-24 | 2008-10-30 | Shanghai Tong-Jie-Liang Biomaterials Co., Ltd | Polylactic acid composition and the production method |
| CN101787113B (en) * | 2010-01-21 | 2011-11-23 | 上海大学 | Method and device for improving crystallizing performances of polyactic acid by pulse magnetic field |
| TWI421163B (en) * | 2011-07-28 | 2014-01-01 | Chung Shan Inst Of Science | Method for making a poly-lactate/silica composite |
| CN113667102A (en) * | 2021-08-20 | 2021-11-19 | 浙江大学衢州研究院 | Method for preparing high-molecular-weight polylactic acid based on nucleating agent |
| CN115785405A (en) * | 2022-11-30 | 2023-03-14 | 厦门长塑实业有限公司 | Melt polymerization tackifying method for recycled polylactic acid |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104249521B (en) * | 2013-06-28 | 2016-04-27 | 允友成(宿迁)复合新材料有限公司 | A kind of multilayer film and manufacture method thereof and application |
| WO2015168922A1 (en) * | 2014-05-09 | 2015-11-12 | Jf Polymers (Suzhou) Co. Ltd. | Highly crystalline poly (lactic acid) filaments for material- extrusion based additive manufacturing |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2966728B2 (en) * | 1994-07-07 | 1999-10-25 | 株式会社クボタ | Paddy working machine |
| JP3350605B2 (en) * | 1995-01-13 | 2002-11-25 | カネボウ株式会社 | Method for producing polylactic acid |
| US20050001358A1 (en) * | 2001-12-28 | 2005-01-06 | Kenji Nakazawa | Polylactic acid-based resin compositions, molded articles and process for producing the same |
| CN101054438A (en) * | 2007-04-24 | 2007-10-17 | 上海同杰良生物材料有限公司 | Method of preparing solid state condensation viscosity enhancing polylactic acid |
-
2007
- 2007-04-24 CN CNA200710039824XA patent/CN101054438A/en active Pending
-
2008
- 2008-01-25 WO PCT/CN2008/070185 patent/WO2008128448A1/en active Application Filing
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2008128448A1 (en) * | 2007-04-24 | 2008-10-30 | Shanghai Tong-Jie-Liang Biomaterials Co., Ltd | Polylactic acid composition and the production method |
| CN101787113B (en) * | 2010-01-21 | 2011-11-23 | 上海大学 | Method and device for improving crystallizing performances of polyactic acid by pulse magnetic field |
| TWI421163B (en) * | 2011-07-28 | 2014-01-01 | Chung Shan Inst Of Science | Method for making a poly-lactate/silica composite |
| CN113667102A (en) * | 2021-08-20 | 2021-11-19 | 浙江大学衢州研究院 | Method for preparing high-molecular-weight polylactic acid based on nucleating agent |
| CN115785405A (en) * | 2022-11-30 | 2023-03-14 | 厦门长塑实业有限公司 | Melt polymerization tackifying method for recycled polylactic acid |
| CN115785405B (en) * | 2022-11-30 | 2024-04-26 | 厦门长塑实业有限公司 | Melt polymerization tackifying method for recycling polylactic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2008128448A1 (en) | 2008-10-30 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101054438A (en) | Method of preparing solid state condensation viscosity enhancing polylactic acid | |
| Ghalia et al. | Biodegradable poly (lactic acid)-based scaffolds: synthesis and biomedical applications | |
| JP3776578B2 (en) | Biodegradable plastic composition and method for adjusting biodegradation rate of biodegradable plastic | |
| Zeng et al. | Synthesis and Properties of Biodegradable Poly (butylene succinate-co-diethylene glycol succinate) Copolymers | |
| CN111848933B (en) | Preparation method of degradable copolyester | |
| CN1167776A (en) | Process for producing polymeric lactic acid | |
| JPH08500131A (en) | Poly (3-hydroxyalkanoate) and method for producing the same | |
| JP2003238672A (en) | Method for producing poly(lactic acid) block copolymer | |
| WO2011060650A1 (en) | Biodegradable aromatic-aliphatic copolyester and preparation method thereof | |
| CN105131259B (en) | Biological guanidine compound system catalytic fusion solid phase synthesizes high-molecular-weight poly alpha-hydroxy acid | |
| CN1806919A (en) | Use of stannous benzoate as catalyst | |
| Jiang et al. | Synthesis of Poly (butylene adipate terephthalate)-co-poly (glycolic acid) with Enhanced Degradability in Water | |
| JP2007100104A (en) | Polylactic acid block copolymer, its preparation process, molded article and polylactic acid composition | |
| Aniśko et al. | Polylactide: From synthesis and modification to final properties | |
| KR101502051B1 (en) | Eco-friendly Copolyester Resin and Process of Preparing Same | |
| CN101492441B (en) | Uses of benzoic acid stannous as catalyst | |
| CN1331912C (en) | Method of preparing high molecular weight polylactic acid using solid phase polymerization | |
| CN115667361A (en) | Autocatalytic rapid degradation polyester polymer and preparation method and application thereof | |
| Xue | Synthesis, Modification and Application of Polylactic Acid | |
| CN107540824A (en) | The method of macromole evocating agent and the condensation open loop solid phase combination synthesis poly- L/D lactic acid of superelevation isotacticity | |
| JP4744675B2 (en) | Process for producing biodegradable aliphatic polyester | |
| Kumar et al. | Biopolymers based on carboxylic acids derived from renewable resources | |
| CN115011089B (en) | Polyglycolic acid composition and thin-wall injection molding cutlery box prepared from same | |
| CN102850538A (en) | Non-lactic acid hydroxy group-terminated polylactic acid and its preparation method | |
| JP3484819B2 (en) | Method for producing biodegradable aliphatic polyester carbonate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |