CN111471166A - Method for improving polyester polycondensation reaction rate - Google Patents
Method for improving polyester polycondensation reaction rate Download PDFInfo
- Publication number
- CN111471166A CN111471166A CN202010339778.0A CN202010339778A CN111471166A CN 111471166 A CN111471166 A CN 111471166A CN 202010339778 A CN202010339778 A CN 202010339778A CN 111471166 A CN111471166 A CN 111471166A
- Authority
- CN
- China
- Prior art keywords
- polyester
- reaction
- polycondensation reaction
- reaction rate
- catalyst
- 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
- C08G63/12—Polyesters derived from hydroxycarboxylic acids or from polycarboxylic acids and polyhydroxy compounds derived from polycarboxylic acids and polyhydroxy compounds
- C08G63/16—Dicarboxylic acids and dihydroxy compounds
- C08G63/20—Polyesters having been prepared in the presence of compounds having one reactive group or more than two reactive groups
-
- 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
- C08G63/66—Polyesters containing oxygen in the form of ether groups
- C08G63/668—Polyesters containing oxygen in the form of ether groups derived from polycarboxylic acids and polyhydroxy compounds
Abstract
The invention relates to the technical field of polyester synthesis, and discloses a method for improving the polyester polycondensation reaction rate aiming at the problems of poor operability and environmental pollution of the polyester reaction industry in the prior art, which comprises the following steps: (1) uniformly mixing diacid monomer, diol monomer, polyfunctional group additive and catalyst, carrying out esterification reaction under the condition of heating and pressurizing, and dehydrating; (2) and carrying out polycondensation reaction under the conditions of heating and vacuumizing to generate a long-chain polymer. The method for improving the polycondensation reaction rate of the polyester is provided, under the condition that parameters such as catalyst content, reaction temperature, pressure and the like are not changed, a small amount of polyfunctional additive is added to increase reaction sites of the polycondensation reaction of the polyester, and meanwhile, a short branching structure is introduced into a polyester chain, so that the melt fluidity is enhanced, the contact probability of end groups under the stirring action in the reaction process is increased, the reaction rate is further improved, no by-product is generated, and the operation process is simple and efficient.
Description
Technical Field
The invention relates to the technical field of polyester synthesis, in particular to a method for improving the polycondensation reaction rate of polyester.
Background
In the production process of polyester PET, the polycondensation reaction, especially the final polycondensation reaction time, has direct influence on various technical indexes such as intrinsic viscosity of the product. Under the condition of the existing production equipment, the polycondensation reaction time is generally 2-3 hours, the problem of high energy consumption is caused by long reaction time and high stirring power, and the energy consumption can be reduced and the yield can be improved by improving the reaction rate to shorten the reaction time. The common catalyst for polyester production at present is an antimony catalyst, the polycondensation reaction rate can be improved to a certain extent by increasing the addition amount of the catalyst, however, the antimony emission of the downstream textile dyeing and finishing industry is strictly controlled, and the improvement of the catalyst content in the fiber-grade polyester synthesis is not a proper method for accelerating the reaction due to the consideration of cost and environmental protection.
Patent No. TW496880B, entitled "a method for increasing the polycondensation reaction rate of PET", which additionally adds a certain amount of ethylene glycol after the end of the esterification reaction, shows that the viscosity of the sample to which ethylene glycol is added is higher in the same reaction time, indicating that the reaction rate is increased, and supposedly that the addition of ethylene glycol at the beginning of the polycondensation reaction is advantageous for increasing the reactivity. However, the implementation of the method is limited to glassware experimental equipment, the industrialization cost is not considered, and the method has no direct reference significance to a continuous production line.
The patent No. CN1552754A, the name of which is "a method for shortening the polycondensation reaction time of polyester", does not change other reaction conditions, and only needs to add a certain amount of zinc compound in the polycondensation reaction process to shorten the polycondensation reaction time of the conventional polyester production by 25-60%. The zinc compound in the method can be regarded as a catalyst in nature, and although the effect of improving the reaction rate is remarkable, the problems of downstream environmental protection and cost still exist.
Disclosure of Invention
The invention aims to overcome the problems of poor operability and environmental pollution of the polyester reaction industry in the prior art, and provides a method for improving the polyester polycondensation reaction rate.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for increasing the rate of a polyester polycondensation reaction, the polyester polycondensation process comprising the steps of:
(1) uniformly mixing diacid monomer, diol monomer, polyfunctional group additive and catalyst, carrying out esterification reaction under the condition of heating and pressurizing, and dehydrating;
(2) and carrying out polycondensation reaction under the conditions of heating and vacuumizing to generate a long-chain polymer.
According to the invention, a certain amount of polyfunctional compounds capable of reacting with hydroxyl and/or carboxyl in polyester are added into polyester monomers, and then a specific catalyst and a polyester monomer substrate with a specific carbon chain length are matched to react under a specific temperature and pressure environment, so that the content of active end groups in a reaction system is increased by the additive, thereby initiating and promoting chain growth in a polycondensation process more quickly, shortening the reaction time and greatly improving the polymerization reaction efficiency of the polyester.
The diacid monomer is one or more of terephthalic acid, isophthalic acid and phthalic acid; the diol monomer is one or more of C2-12 diols.
Preferably, the multifunctional additive contains one or more of hydroxyl, epoxy, carboxyl, anhydride, isocyanate and amino.
Preferably, the multifunctional additive is a non-polymeric small molecule with a number of functional groups greater than or equal to 2.
Preferably, the number of functional groups of the polyfunctional additive is 3 or more and 6 or less.
Too few functional groups to form a branched structure; too many functional groups are present, which leads to a limited number of functional groups which react with the polyester end groups due to increased steric hindrance.
Preferably, the catalyst is an antimony catalyst, including ethylene glycol antimony, antimony trioxide or antimony acetate.
Preferably, the number of carbon atoms in the carbon chain of the diacid monomer and the diol monomer is not more than 6.
If the content of the end group of the monomer with the same mass and the overlong carbon chain is less, the active functional group is less, the contact chance with the functional group of the polyester monomer in the reaction process is reduced, and the reaction rate is low.
Preferably, the polyfunctional additive in step (1) is present in an amount of 0.1 to 1.0% by weight of the long-chain polymer.
If the addition amount is too small, the accelerating effect on the polyester polycondensation rate is not obvious, and if the addition amount is too high, the reaction is too violent, and crosslinking is easily formed.
Preferably, the amount of catalyst added in step (1) is 0.02 to 0.07% by mass of the long-chain polymer.
Too little catalyst addition can result in insufficient reaction of the polyester monomers, and if excessive addition can result in waste of raw materials and introduction of additional impurities, reducing the purity of the long-chain polymer.
Preferably, the heating temperature in the step (1) is 225-.
Steam is generated in the esterification reaction process, the pressure is always increased, pressure relief is needed when the pressure is too high, water is slowly discharged in the latter half of the reaction, and the pressure is slowly reduced to zero.
Preferably, the heating temperature in the step (2) is 265-280 ℃, and the vacuum degree of vacuumizing is less than or equal to 200 Pa.
The polycondensation reaction draws out small molecules such as water molecules, reduces side reactions, promotes the reaction to proceed in the positive direction, and directly results in the improvement of molecular weight and the increase of the polymerization degree/molecular weight of the final polyester.
The invention has the following beneficial effects:
(1) the method for improving the polycondensation reaction rate of the polyester is provided, and under the condition that parameters such as catalyst content, reaction temperature, pressure and the like are not changed, a small amount of polyfunctional additive is added to increase the reaction sites of the polycondensation reaction of the polyester so as to achieve the purpose of improving the polycondensation reaction rate;
(2) the optimal rate-increasing effect can only be achieved by determining that the polyester monomer with the number of functional groups of the polyfunctional additive being more than or equal to 3 and less than or equal to 6 is matched with the polyester monomer with the number of carbon atoms on the carbon chain being less than or equal to 6. The polyfunctional group molecules not only increase the reaction sites in the system, but also introduce a short branched structure into the polyester chain, thereby enhancing the melt fluidity, increasing the contact probability of the end groups under the stirring action in the reaction process, and further improving the reaction rate;
(3) the method does not obviously increase the cost, produces no by-products, and has simple and efficient operation process.
Detailed Description
Intrinsic viscosity test method:
a certain amount of polyester sample was dissolved in phenol: in a mixed solvent of tetrachloroethane in a mass ratio of 3:2, the intrinsic viscosity of the sample was measured at room temperature using an Ubbelohde viscometer.
The invention is further described with reference to specific embodiments.
Example 1
Adding 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of ethylene glycol antimony and 9.6g of multifunctional compound bis (trimethylolpropane) propane into a 2.5L reaction kettle, starting esterification reaction at 225 ℃, controlling the pressure to be less than or equal to 0.33Mpa, vacuumizing to 60Pa after water outlet is finished, starting polycondensation reaction at 270 ℃, observing the torque indication of a motor, recording the time from the increase of the indication to the corresponding torque of a fiber-grade polyester sample, stopping the reaction, and discharging.
Example 2
The difference from the example 1 is that 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of ethylene glycol antimony and 0.96g of multifunctional compound pentaerythritol are added into a 2.5L reaction kettle, esterification reaction is started at 223 ℃, the pressure is controlled to be less than or equal to 0.30Mpa, vacuum pumping is carried out to 40Pa after water outlet is finished, polycondensation reaction is started at 272 ℃, motor torque readings are observed, the time from the reading rise to the reaching of the corresponding torque of the fiber-grade polyester sample is recorded, the reaction is stopped, and discharging is carried out.
Example 3
The difference from the example 2 is that 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of ethylene glycol antimony and 4.8g of multifunctional compound pentaerythritol are added into a 2.5L reaction kettle, the esterification reaction is started at 228 ℃, the pressure is controlled to be less than or equal to 0.32Mpa, after the water outlet is finished, the vacuum is pumped to 30Pa, the polycondensation reaction is started at 273 ℃, the torque indication of a motor is observed, the time from the indication rising to the moment corresponding to the fiber grade polyester sample is recorded, the reaction is stopped, and the material is discharged.
Example 4
The difference from the embodiment 3 is that 830g of terephthalic acid, 827.2g of 1, 6-hexanediol, 0.5g of ethylene glycol antimony and 6.2g of pentaerythritol are added into a 5L reaction kettle, esterification reaction is carried out at the temperature of 235 ℃ and 255 ℃, the pressure is controlled to be less than or equal to 0.35Mpa, after water outlet is finished, the vacuum is pumped to 200Pa, polycondensation reaction is carried out at the temperature of 274 ℃, the torque indication of a motor is observed, the time from the indication rising to the moment corresponding to the torque of the fiber-grade polyester sample is recorded, the reaction is stopped, and discharging is carried out.
Example 5
The difference from the example 3 is that 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of ethylene glycol antimony and 4.8g of multifunctional compound dipentaerythritol are added into a 2.5L reaction kettle, esterification reaction is started at 226 ℃, the pressure is controlled to be less than or equal to 0.30Mpa, after water outlet is finished, vacuum pumping is carried out to 20Pa, polycondensation reaction is started at 270 ℃, motor torque readings are observed, the time from the reading rise to the reaching of the corresponding torque of the fiber-grade polyester sample is recorded, the reaction is stopped, and discharging is carried out.
Comparative example 1 (different from example 2 in that a polyfunctional additive was not added.)
Adding 830g of terephthalic acid, 434g of ethylene glycol and 0.4g of ethylene glycol antimony into a 2.5L reaction kettle, starting esterification reaction at 225 ℃, controlling the pressure to be less than or equal to 0.33Mpa, vacuumizing to 40Pa after water outlet, starting polycondensation reaction at 272 ℃, observing the torque indication of a motor, recording the time from the increase of the indication to the reaching of the corresponding torque of a fiber-grade polyester sample, stopping the reaction, and discharging.
Comparative example 2 (different from example 2 in that 0.96g of maleic anhydride was added instead of pentaerythritol, and the number of anhydride functional groups was 2.)
Adding 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of ethylene glycol antimony and 0.96g of polyfunctional compound maleic anhydride into a 2.5L reaction kettle, starting esterification reaction at 226 ℃, controlling the pressure to be less than or equal to 0.32Mpa, vacuumizing to 20Pa after water is discharged, starting polycondensation reaction at 272 ℃, observing the torque indication of a motor, recording the time from the increase of the indication to the corresponding torque of a fiber-grade polyester sample, stopping the reaction, and discharging.
Comparative example 3 (different from example 2 in that 0.48g of pentaerythritol was added, and halving was conducted based on the example) 830g of terephthalic acid, 434g of ethylene glycol, 0.4g of antimony ethylene glycol and 0.48g of pentaerythritol polyfunctional compound were charged into a 2.5L reaction vessel, esterification reaction was started at 227 ℃ with the pressure being controlled to 0.33MPa or less, vacuum was applied to 30Pa after the end of water discharge, polycondensation reaction was started at 272 ℃, motor torque readings were observed, the time taken from the rise of the readings to the arrival of the torque corresponding to the fiber grade polyester sample was recorded, the reaction was stopped, and discharge was conducted.
Comparative example 4 (different from example 4 in that the diol monomer is 1,4 cyclohexanedimethanol containing 8 carbon atoms.) 830g of terephthalic acid, 1009g of 1,4 cyclohexanedimethanol, 0.7g of ethylene glycol antimony and 8.4g of pentaerythritol are added into a 5L reaction kettle, esterification reaction is carried out at 235-255 ℃ under the pressure of 0.35MPa or less, vacuum pumping is carried out to 160Pa after water outlet is finished, polycondensation reaction is carried out at 270-280 ℃, motor torque indication is observed, the time from the indication rising to the moment corresponding to the torque of the fiber-grade polyester sample is recorded, and the reaction is stopped and the material is discharged.
The evaluation parameter indexes of the synthesis paths for increasing the polycondensation reaction rate of the polyesters of examples 1 to 5 and comparative examples 1 to 4 are shown in Table 1. The polycondensation reaction time in the table refers to the time recorded from the start of the torque rise to the discharge.
TABLE 1 improvement of polyester polycondensation reaction Rate Synthesis Path related evaluation index
| Item | Additive content | Polycondensation time (min) | Intrinsic viscosity (dl/g) |
| Example 1 | 1.0％ | 30 | 0.642 |
| Example 2 | 0.1％ | 61 | 0.656 |
| Example 3 | 0.5％ | 25 | 0.650 |
| Example 4 | 0.5％ | 59 | 0.647 |
| Example 5 | 0.5％ | 46 | 0.653 |
| Comparative example 1 | 0 | 150 | 0.645 |
| Comparative example 2 | 0.1％ | 120 | 0.652 |
| Comparative example 3 | 0.05％ | 128 | 0.643 |
| Comparative example 4 | 0.5％ | 119 | 0.651 |
And (4) conclusion: in the preparation methods of examples 1 to 5, the reaction sites and the fluidity of the reaction system of the polyester polycondensation reaction can be increased by adding a small amount of polyfunctional additive without changing the catalyst content, the reaction temperature, the pressure and other parameters, so as to achieve the purpose of increasing the polycondensation reaction rate, and the polycondensation reaction time can be shortened by 80% at most;
the difference between the comparative example 1 and the example 2 is that the reaction rate is the level of the conventional fiber-grade polyester without adding the polyfunctional additive, and the number of the reactive groups is less, so the reaction time is greatly prolonged compared with the reaction time of the example 2;
comparative example 2 is different from example 2 in that the reaction rate is not improved as much as 4 functional pentaerythritol by adding maleic anhydride which is an additive containing 2 functional groups, and the reaction time is longer than that of example 2 because of less reactive groups and no branched structure introduced;
comparative example 3 differs from example 2 in that the content of additive is halved, less than 0.01%, and the reaction time is only slightly shortened compared to the conventional polyester, comparative example 1, twice that of example 2;
comparative example 4 is different from example 4 in that the diol monomer as a reaction substrate contains 8 carbon atoms and has a cyclic structure, and the molecule is less mobile than a chain molecule having a low number of carbon atoms, so that the reaction time is longer.
It can be seen from the data of examples 1-5 and comparative examples 1-4 that the above requirements can be satisfied in all respects only by the embodiments within the scope of the claims of the present invention, giving the optimum results, the fastest polycondensation reaction rate under the condition of ensuring the same intrinsic viscosity of the polyester product. The change of the mixture ratio and the replacement/addition/subtraction of the raw materials can bring corresponding negative effects.
The raw materials and equipment used in the invention are common raw materials and equipment in the field if not specified; the methods used in the present invention are conventional in the art unless otherwise specified.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the protection scope of the technical solution of the present invention.
Claims (10)
1. A method for increasing the polycondensation reaction rate of polyester, wherein the polycondensation process of polyester comprises the steps of:
(1) uniformly mixing diacid monomer, diol monomer, polyfunctional group additive and catalyst, carrying out esterification reaction under the condition of heating and pressurizing, and dehydrating;
(2) and carrying out polycondensation reaction under the conditions of heating and vacuumizing to generate a long-chain polymer.
2. The method of claim 1, wherein the multifunctional additive comprises one or more of hydroxyl, epoxy, carboxyl, anhydride, isocyanate, and amino.
3. The method of claim 1, wherein the multifunctional additive has a number of functional groups greater than or equal to 2.
4. A method for increasing the polycondensation reaction rate of polyester according to claim 1, 2 or 3, wherein the number of functional groups in the polyfunctional additive is 3 or more and 6 or less.
5. The method of claim 1, wherein the catalyst is an antimony-based catalyst comprising ethylene glycol antimony, antimony trioxide or antimony acetate.
6. The method of claim 1, wherein the number of carbon atoms in the carbon chain of the diol monomer is less than or equal to 6.
7. The method for increasing the polycondensation reaction rate of polyester according to claim 1, wherein the multifunctional additive in step (1) is present in an amount of 0.1-1.0% by weight based on the mass of the long-chain polymer.
8. The method for increasing the polycondensation reaction rate of polyester according to claim 1, wherein the amount of catalyst added in step (1) is 0.02 to 0.07% by mass of the long-chain polymer.
9. The method as claimed in claim 1, wherein the heating temperature in step (1) is 225 ℃ and 255 ℃ and the pressurization pressure is controlled to be 0.35MPa or less.
10. The method as claimed in claim 1, wherein the heating temperature in step (2) is 265 ℃ and 280 ℃, and the degree of vacuum is less than or equal to 200 Pa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010339778.0A CN111471166A (en) | 2020-04-26 | 2020-04-26 | Method for improving polyester polycondensation reaction rate |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010339778.0A CN111471166A (en) | 2020-04-26 | 2020-04-26 | Method for improving polyester polycondensation reaction rate |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111471166A true CN111471166A (en) | 2020-07-31 |
Family
ID=71755748
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010339778.0A Pending CN111471166A (en) | 2020-04-26 | 2020-04-26 | Method for improving polyester polycondensation reaction rate |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111471166A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113150256A (en) * | 2021-04-21 | 2021-07-23 | 浙江恒澜科技有限公司 | Branched copolyester for bead foaming and preparation method thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2828200A1 (en) * | 2001-08-03 | 2003-02-07 | Tergal Fibres | Polyester especially useful for producing textile fibers includes an ether polyol with at least three hydroxy functions |
| CN102643414A (en) * | 2012-04-03 | 2012-08-22 | 浙江佳宝新纤维集团有限公司 | Preparation method of hydrophilic antistatic polyester |
| CN103789866A (en) * | 2014-01-26 | 2014-05-14 | 东华大学 | Preparation method of polyhydric polyester fiber |
| CN103788349A (en) * | 2014-01-26 | 2014-05-14 | 东华大学 | Preparation method of functional polyester |
| CN103804665A (en) * | 2014-01-26 | 2014-05-21 | 东华大学 | Preparation method of polyhydroxyl polyester |
-
2020
- 2020-04-26 CN CN202010339778.0A patent/CN111471166A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2828200A1 (en) * | 2001-08-03 | 2003-02-07 | Tergal Fibres | Polyester especially useful for producing textile fibers includes an ether polyol with at least three hydroxy functions |
| CN102643414A (en) * | 2012-04-03 | 2012-08-22 | 浙江佳宝新纤维集团有限公司 | Preparation method of hydrophilic antistatic polyester |
| CN103789866A (en) * | 2014-01-26 | 2014-05-14 | 东华大学 | Preparation method of polyhydric polyester fiber |
| CN103788349A (en) * | 2014-01-26 | 2014-05-14 | 东华大学 | Preparation method of functional polyester |
| CN103804665A (en) * | 2014-01-26 | 2014-05-21 | 东华大学 | Preparation method of polyhydroxyl polyester |
Non-Patent Citations (2)
| Title |
|---|
| 汪多仁: "《精细化工中间体》", 31 December 2008, 海洋出版社 * |
| 胡学贵: "《高分子化学及工艺学》", 13 December 1991, 化学工业出版社 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113150256A (en) * | 2021-04-21 | 2021-07-23 | 浙江恒澜科技有限公司 | Branched copolyester for bead foaming and preparation method thereof |
| CN113150256B (en) * | 2021-04-21 | 2022-08-26 | 浙江恒逸石化研究院有限公司 | Branched copolyester for bead foaming and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112521592B (en) | Biodegradable polyester and preparation method thereof | |
| US3427287A (en) | Method for preparing polyester resins | |
| US6103859A (en) | Late addition of supplemental ethylene glycol in the preparation of copolyesters | |
| US4016142A (en) | Process for the control of carboxyl end groups in fiber-forming polyesters | |
| US3496146A (en) | Preparation of glycol terephthalate linear polyester by direct esterification of terephthalic acid | |
| US4097468A (en) | Process for preparing polyesters | |
| CN109456469B (en) | Preparation method of high-fluidity cation modified copolyester | |
| CN112608454A (en) | Basic production formula for preparing non-crystalline copolyester PETG by using recycled PET plastic and process method thereof | |
| US3497473A (en) | Process for the preparation of polyethylene terephthalate | |
| US4329444A (en) | Production of polyesters | |
| CN111072938B (en) | Low-melting-point polyester and preparation method thereof | |
| US4499261A (en) | Process for the continuous production of polybutylene terephthalate of high molecular weight | |
| CN111471166A (en) | Method for improving polyester polycondensation reaction rate | |
| AU2005294576B2 (en) | Process for producing polytrimethylene terephthalate | |
| US3528945A (en) | Acetylacetonates as polycondensation catalysts in the direct esterification method of preparing polyesters | |
| CN103304795A (en) | Organosilicone copolyester | |
| CN111087583B (en) | Preparation method of low-end carboxyl PBT resin | |
| JP4460453B2 (en) | Method for preparing trimethylene terephthalate oligomer | |
| CN113801311B (en) | Polyester preparation method | |
| WO2007026650A1 (en) | Polybutylene terephthalate and process for production thereof | |
| CN108892770B (en) | Method for inhibiting side reaction of tetrahydrofuran in polymerization process | |
| CN108976404A (en) | The poly- 2,6- (ethylene naphthalate) and its preparation method of modified by cardanol | |
| KR102202138B1 (en) | Method for Preparing Polycyclohexylenedimethylene Terephthalate Glycol | |
| US3536667A (en) | Process of preparing polyethylene terephthalate using glyceryl antimonite as polycondensation catalyst | |
| US3511812A (en) | Preparation of polyesters using cocatulyst of lithium amide an in transesterification reaction |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| CB02 | Change of applicant information |
Address after: 311200 29 Chenghu Road, Yaqian Town, Xiaoshan District, Hangzhou City, Zhejiang Province Applicant after: Zhejiang Hengyi Petrochemical Research Institute Co.,Ltd. Address before: 311200 Room 501, 3 Blocks, Pearl Plaza, South Bank of Xiaoshan Economic and Technological Development Zone, Xiaoshan District, Hangzhou City, Zhejiang Province Applicant before: ZHEJIANG HENGLAN TECHNOLOGY Co.,Ltd. |
|
| CB02 | Change of applicant information | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200731 |
|
| RJ01 | Rejection of invention patent application after publication |