CN101220109A - Supercritical fluid devolatilization method of verelite - Google Patents

Supercritical fluid devolatilization method of verelite Download PDF

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Publication number
CN101220109A
CN101220109A CNA2008100594432A CN200810059443A CN101220109A CN 101220109 A CN101220109 A CN 101220109A CN A2008100594432 A CNA2008100594432 A CN A2008100594432A CN 200810059443 A CN200810059443 A CN 200810059443A CN 101220109 A CN101220109 A CN 101220109A
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China
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polystyrene
devolatilization
supercritical
pending
continous way
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CNA2008100594432A
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Chinese (zh)
Inventor
蒋春跃
高建荣
陈杰
皮建彪
潘勤敏
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Zhejiang University of Technology ZJUT
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Zhejiang University of Technology ZJUT
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Priority to CNA2008100594432A priority Critical patent/CN101220109A/en
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids

Abstract

The invention discloses a devolatilization method of polystyrene supercritical fluid. The method takes CO2 as a supercritical medium and renders the polystyrene to be treated to fully contact with the supercritical CO2 in a devolatiliation device under supercritical condition so as to remove volatile content in the polystyrene, thus obtaining purified polystyrene. The method of the invention greatly improves the devolatilization process and effect of the polystyrene. The volatile content of a polymer can be reduced to 1ppm or less based on calculation of content of residual monomers. The method is simple and highly efficient and has good devolatilization effect, thereby having good application prospect.

Description

A kind of DEVOLATILIZATION OF POLYSTYRENE BY SUPERCRITICAL FLUID method
(1) technical field
The present invention relates to the devolatilization method of a kind of polystyrene (PS).
(2) background technology
In the production process of polymkeric substance, often contain small-molecule substances such as the intact residual monomer of unreacted, solvent, by product in the product, system is referred to as to wave branch.These wave the existence of branch impurity, thereby not only the performance of impact polymer has influence on its terminal use, and will user's health and environment be worked the mischief.Therefore, devolatilization just becomes the important step in the polymkeric substance last handling process.Devolatilization mode in the existing industrial production is the vacuum removal method of latent heat dependent form, and this method is the energy consumption height not only, and in the later stage of devolatilization, because of the rapid rising of system viscosity, makes the spread coefficient of waving branch sharply descend, and causes the mass-transfer efficiency of equipment low.Because polymkeric substance is longer in the hot environment time of living in, very easily cause the degraded of superpolymer simultaneously.Along with the application of polymkeric substance as aspects such as food product pack, artificial organs and medical macromolecular materials, strict day by day to the requirement of waving branch content, and existing industrial devolatilization method is owing to be subjected to the restriction of factors such as vacuum technique, equilibrium conditions, the limit has become, the residual monomer content that utilizes existing industrial technology to carry out in the step reduction polymeric articles is very difficult, causes present polymeric articles to wave the requirement that too high levels is difficult to satisfy above-mentioned application because of it.Therefore, must seek new technological method, break through the prior art bottleneck.
Using supercritical fluid technology platform (SCFTP) is the effective way that breaks through above-mentioned prior art bottleneck.Supercutical fluid (SCF) has unique physicochemical property: the density of (1) quasi-liquid makes its dissolving power to chemical compound lot be strengthened also to regulate and control effectively; (2) like the hereditary property and zero surface tension of gas, the mass-transfer performance of high sticking system is strengthened.CO 2Be a kind of environmental gas, have gentle critical properties (critical temperature is 304K, and emergent pressure is 7.38MPa), and nontoxic, inexpensive, do not fire, excellent/characteristics such as property is lazy, thereby become the first-selected and the most frequently used cleaning solvent of SCFTP.Be based upon the polymkeric substance devolatilization process on the SCFTP, referred to herein as the supercritical fluid devolatilization (SFDV) of polymkeric substance.In view of the above, then can strengthen the devolatilization process of polymkeric substance, improve devolatilization efficient, reduce the residual monomer content in the polymeric articles.
Held first supercritical fluid extraction (SFE) symposium in Germany in 1978, next year, Germany Hag company has set up first hand and has utilized the SFE technology to remove the factory of caffeine from coffee, becomes the new milestone of SFE technology, indicates also that SCFTP begins to form.From then on the SFE technology become the new technology of modern extracting and separating and be common people known (referring to Angew Chem Int Ed, 1978,17:702).For example, 1974-1978, doctor Zosel of Germany utilizes supercritical CO 2The caffeine of extraction in the coffee berry finds that SFE has such as cleaning, many remarkable advantages (referring to US3,806,619) such as efficient than common organic solvent extraction.Entered since the eighties in last century, the application surface of supercritical fluid technology is extensive day by day, for example, utilizes supercutical fluid that polymkeric substance is carried out swelling, so carry secretly medicine insert embedding (referring to J ApplPolym Sci, 1992,46:231).The application of supercritical fluid technology aspect polymer purification also obtained bigger progress, U.S. Pat 4,892, and 931 have proposed a kind of supercritical fluid devolatilization method of polycarbonate; US5,049,647 supercritical fluid devolatilization method that proposes the PET polyester.Yet, different polymkeric substance has the specific branch impurity (mainly being monomer) of waving, desire to use effectively the supercritical fluid devolatilization technology, then must to wave branch in SCF solubleness and wave the mass transport mechanism of branch in polymkeric substance deep understanding arranged, to draw suitable process conditions.So far do not see the relevant report of the supercritical fluid devolatilization method of polystyrene (PS) as yet.
(3) summary of the invention
The technical problem to be solved in the present invention is to provide the supercritical fluid devolatilization method of a kind of polystyrene (PS), to remove the small molecular weight impurities (being referred to as to wave branch) such as residual monomer ST in the polystyrene (PS), reaches the purpose of the above-mentioned polymkeric substance of purifying.
For solving the problems of the technologies described above, the present invention adopts following technical scheme: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2The branch of waving in the polystyrene is removed in fully contact in the devolatilization device, obtains the polystyrene behind the purifying.
In above-mentioned devolatilization process, need be controlled under the super critical condition and carry out, promptly controlled temperature and pressure are CO 2The temperature and the pressure condition of super/nearly stagnation point, specifically, controlled temperature is more than or equal to CO 2Critical temperature and less than the decomposition temperature of polystyrene, can be higher than the melt temperature that also can be lower than polystyrene PS, preferred temperature is 40～250 ℃.
In operating process, control pressure is CO at least 21.1 times of emergent pressure, preferred 8～30MPa.
The CO that is adopted in the inventive method 2The volume (under the standard state) that flow velocity is per hour consumed by every kilogram of pending polymkeric substance, its lower limit is not less than 2.0m 3/ (hkgPS), but specifically selecting for use of flow velocity needs decide according to the purity requirement of product, when purity requirement is higher, should adopt bigger CO 2Flow velocity.But preferably be taken at 2.0～10.0m 3/ (hkgPS) in the scope of (under the standard state).
The devolatilization device that the present invention adopts can be step, and the intermittent type device is defined as polymkeric substance when carrying out the devolatilization operation here, is the device of producing in batches; Also can be continous way, the continous way device here be defined as to be aggregated in and carries out devolatilization when operation, and polymer stabilizing is continuously by the devolatilization device, promptly polymkeric substance with certain flow rate (quality of handled polymkeric substance of unit time) by the devolatilization device.No matter the devolatilization device is step or continous way, CO 2Always contact certain hour with the interior pending polymer poly vinylbenzene PS of said apparatus, wave branch impurity in the polymkeric substance to remove as be moving phase.The present invention preferably carries out the devolatilization operation in intermittent type fixed bed or continous way stirring tank.
When devolatilization operates in when carrying out in the continous way stirring tank, the speed that adds pending polystyrene can be according to the purity requirement that branch content and polystyrene needs reach of waving in the pending polystyrene, by with supercritical CO 2Flow velocity coordinate mutually to adjust, recommend pending polystyrene with the flow rate of 0.1～10kg/h by the continous way stirring tank.
When devolatilization operates in when carrying out in the intermittent type fixed bed, can decide the devolatilization time according to the purity requirement that branch content and polystyrene needs reach of waving in the pending polystyrene.Wherein waving branch (mainly being residual monomer ST) content can adopt supercritical fluid chromatography or solvent extraction/chromatography to carry out assay determination.
Among the present invention, when described method was carried out in the continous way stirring tank, concrete grammar was as follows: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2Contact in the continous way stirring tank, the CONTROL PROCESS condition is: temperature is 40～250 ℃, and pressure is 8～30MPa, and pending polystyrene passes through continous way stirring tank, supercritical CO with the flow rate of 0.1～10kg/h 2Flow velocity is 2.0～10.0m 3/ (hkgPS), pending polystyrene and supercritical CO 2In the continous way stirring tank fully after the contact, obtain the polystyrene behind the purifying.
When described method is carried out in the intermittent type fixed bed, concrete grammar is recommended as follows: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2Contact in the intermittent type fixed bed, the CONTROL PROCESS condition is: temperature is 40～250 ℃, and pressure is 8～30MPa, and every batch of pending polystyrene treatment capacity is 1～60g/L, supercritical CO 2Flow velocity is 2.0～10.0m 3/ (hkgPS), pending polystyrene and supercritical CO 2In the intermittent type fixed bed fully after the contact, obtain the polystyrene behind the purifying.
Compared with prior art, adopt the inventive method p-poly-phenyl ethene to implement supercritical fluid devolatilization, its technique effect is mainly reflected in following two aspects:
1, because waving the diffusion of branch in polymkeric substance is strengthened, can greatly strengthen the devolatilization process, sign amount diffusion coefficient D=10 -7～10 -8Cm.s -2And existing devolatilization technological method, it spreads system D ≅ 10 - 11 cm · s - 2 .
2, can greatly strengthen the devolatilization effect, promptly greatly reduced and to have waved branch content in the polymkeric substance, if in residual monomer content, can reduce to below the 1ppm, and existing devolatilization technology, owing to be subjected to the restriction of vacuum technique, equilibrium conditions etc., the limit has become, the content of residual monomer is higher, is about 3～5% (mass percents).
To sum up, the supercritical fluid devolatilization method of polystyrene provided by the invention (PS) is simple, efficient, devolatilization is effective, has good application prospects.
(4) description of drawings
The structural representation of the intermittent type fixed bed that Fig. 1 is adopted for embodiment of the invention 1-3.
Fig. 2 is the structural representation of the continous way stirring tank that adopted of the embodiment of the invention 4.
(5) embodiment
With specific embodiment technical scheme of the present invention is described further below, but protection scope of the present invention is not limited thereto:
Embodiment 1
Get impure polystyrene PS resin particle 65.1g as raw material, wherein monomer styrene ST content is 1.1% (mass percent).At volume is in the intermittent type fixed bed of 2L, implements the supercritical fluid devolatilization operation, and the processing condition of operation are: temperature is 40 ℃, and pressure is 8MPa, CO 2Flow velocity is 2.0m 3/ (hkgPS).CO 2With polystyrene PS resin particle after contacting 60min under the above-mentioned process conditions, residual monomer ST content is reduced to 0.76% (mass percent); Behind the contact 120min, residual monomer ST content is reduced to 0.45% (mass percent); Behind the contact 180min, the content of residual monomer ST is reduced to 0.33% (mass percent).
Embodiment 2
Get impure polystyrene PS resin particle 67.56g as raw material, wherein monomer styrene ST content is 0.98% (mass percent).At volume is in the intermittent type fixed bed of 2L, implements the supercritical fluid devolatilization operation, and the processing condition of operation are: temperature is 70 ℃, and pressure is 18MPa, CO 2Flow velocity is 2.90m 3/ (hkgPS).CO 2With polystyrene PS resin particle after contacting 60min under the above-mentioned process conditions, residual monomer ST content is reduced to 0.43% (mass percent); Behind the contact 120min, residual monomer ST content is reduced to 0.19% (mass percent); Behind the contact 180min, the content of residual monomer ST is reduced to 0.16% (mass percent).
Embodiment 3
Get impure polystyrene PS resin particle 61.08g as raw material, wherein monomer styrene ST content is 0.87% (mass percent).At volume is in the intermittent type fixed bed of 2L, implements the supercritical fluid devolatilization operation, and the processing condition of operation are: temperature is 70 ℃, and pressure is 30MPa, CO 2Flow velocity is 5.52m 3/ (hkgPS).CO 2With polystyrene PS resin particle after contacting 60min under the above-mentioned process conditions, residual monomer ST content is reduced to 0.015% (mass percent); Behind the contact 120min, residual monomer ST content is reduced to 0.0023% (mass percent); Behind the contact 180min, the content of residual monomer ST is reduced to 0.0001% (mass percent).
Embodiment 4
Get impure polystyrene PS resin particle as raw material, wherein monomer styrene ST content is 2.1% (mass percent).At volume is in the continous way stirring tank of 20L, implements the supercritical fluid devolatilization operation, and the processing condition of operation are: temperature is 250 ℃, and pressure is 18MPa, CO 2Flow velocity is 10m 3/ (hkgPS), the flow rate of polystyrene is 10kg/h.Polystyrene PS melt under above-mentioned process conditions through CO 2After the processing, residual monomer ST content is reduced to 0.15% (mass percent).

Claims (10)

1. the devolatilization method of a polystyrene is characterized in that described method is: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2The branch of waving in the polystyrene is removed in fully contact in the devolatilization device, obtains the polystyrene behind the purifying.
2. the devolatilization method of polystyrene as claimed in claim 1 is characterized in that described super critical condition controlled temperature is more than or equal to CO 2Critical temperature and less than the decomposition temperature of polystyrene.
3. the devolatilization method of polystyrene as claimed in claim 2 is characterized in that described super critical condition controlled temperature is 40～250 ℃.
4. the devolatilization method of polystyrene as claimed in claim 1 is characterized in that described super critical condition control pressure is CO at least 21.1 times of emergent pressure.
5. the devolatilization method of polystyrene as claimed in claim 4 is characterized in that described super critical condition control pressure is 8～30MPa.
6. the devolatilization method of polystyrene as claimed in claim 1 is characterized in that described above-critical state CO 2Flow velocity under standard state, be not less than 2.0m 3/ (hkgPS).
7. the devolatilization method of polystyrene as claimed in claim 6 is characterized in that described above-critical state CO 2Flow velocity be 2.0～10.0m under standard state 3/ (hkgPS).
8. as the devolatilization method of the described polystyrene of one of claim 1～7, it is characterized in that described devolatilization device is intermittent type fixed bed or continous way stirring tank.
9. the devolatilization method of polystyrene as claimed in claim 8 is characterized in that described method carries out in the continous way stirring tank, concrete grammar is as follows: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2Contact in the continous way stirring tank, the CONTROL PROCESS condition is: temperature is 40～250 ℃, and pressure is 8～30MPa, and pending polystyrene passes through continous way stirring tank, supercritical CO with the flow rate of 0.1～10kg/h 2Flow velocity is 2.0～10.0m 3/ (hkgPS), pending polystyrene and supercritical CO 2In the continous way stirring tank fully after the contact, obtain the polystyrene behind the purifying.
10. the devolatilization method of polystyrene as claimed in claim 8 is characterized in that described method carries out in the intermittent type fixed bed, concrete grammar is as follows: with CO 2Be supercritical medium, under super critical condition, make pending polystyrene and supercritical CO 2Contact in the intermittent type fixed bed, the CONTROL PROCESS condition is: temperature is 40～250 ℃, and pressure is 8～30MPa, and every batch of pending polystyrene treatment capacity is 1～60g/L, supercritical CO 2Flow velocity is 2.0～10.0m 3/ (hkgPS), pending polystyrene and supercritical CO 2In the intermittent type fixed bed fully after the contact, obtain the polystyrene behind the purifying.
CNA2008100594432A 2008-01-22 2008-01-22 Supercritical fluid devolatilization method of verelite Pending CN101220109A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104004331A (en) * 2014-05-05 2014-08-27 上海锦湖日丽塑料有限公司 Low-emission PC/ABS alloy and preparation method thereof
CN111607022A (en) * 2020-06-11 2020-09-01 黄河三角洲京博化工研究院有限公司 Devolatilization method of trans-butyl amyl rubber
CN113999332A (en) * 2021-11-17 2022-02-01 华东理工大学 Supercritical carbon dioxide assisted periodic devolatilization process and device
CN114014960A (en) * 2021-10-21 2022-02-08 金聚合科技(宁波)有限公司 System and method for purifying polyolefin
CN114425185A (en) * 2020-10-14 2022-05-03 中国石油化工股份有限公司 Device for removing volatile organic compounds in polymer emulsion

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104004331A (en) * 2014-05-05 2014-08-27 上海锦湖日丽塑料有限公司 Low-emission PC/ABS alloy and preparation method thereof
CN111607022A (en) * 2020-06-11 2020-09-01 黄河三角洲京博化工研究院有限公司 Devolatilization method of trans-butyl amyl rubber
CN111607022B (en) * 2020-06-11 2022-08-02 黄河三角洲京博化工研究院有限公司 Devolatilization method of trans-butyl amyl rubber
CN114425185A (en) * 2020-10-14 2022-05-03 中国石油化工股份有限公司 Device for removing volatile organic compounds in polymer emulsion
CN114014960A (en) * 2021-10-21 2022-02-08 金聚合科技(宁波)有限公司 System and method for purifying polyolefin
CN113999332A (en) * 2021-11-17 2022-02-01 华东理工大学 Supercritical carbon dioxide assisted periodic devolatilization process and device

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