CN100348646C - Catalytic synthesis of alpha-omega-dialkyl polydimethylsiloxane - Google Patents
Catalytic synthesis of alpha-omega-dialkyl polydimethylsiloxane Download PDFInfo
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- CN100348646C CN100348646C CNB2005100681441A CN200510068144A CN100348646C CN 100348646 C CN100348646 C CN 100348646C CN B2005100681441 A CNB2005100681441 A CN B2005100681441A CN 200510068144 A CN200510068144 A CN 200510068144A CN 100348646 C CN100348646 C CN 100348646C
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Abstract
The present invention relates to a continuous process which uses potassium hydroxide as a catalyst under ordinary pressure and uses a water vapor method to synthesize alpha, omega-dihydroxy polydimethyl siloxane. The present invention has the advantages of simple and stable operation, easy control, mild condition, outstanding technical index, low requirement for a reactor, good continuity and high safety.
Description
Technical field
The present invention relates to a kind of production method of silicone rubber products.
Background technology
α, alpha, omega-dihydroxy polydimethyl siloxane (being called for short the hydroxyl polysiloxane) are one of staple products in the silicon rubber.All have a wide range of applications as fields such as building, coating, industrial art in many aspects.Along with the fast development of Building Trade in China in recent years, hydroxyl polysiloxane (building sealant main raw material) demand increases sharply, and simultaneously, industries such as coating, molding are also all keeping great demand to the hydroxyl polysiloxane.Intermittently flow process is adopted in the production of present domestic hydroxyl polysiloxane basically, and its technology is divided polymerization, degraded, termination, devolatilization four-stage, and four processes are all finished in same reactor.The shortcoming of this type of technology is that technology is numerous and diverse, quality product is wayward, the viscosity first-time qualification rate only about 50%, single still production cycle is long, throughput is low, and this process catalyst adopts Tetramethylammonium hydroxide, shortcomings such as exist product colour dark, smell is big, and molecular weight distribution is wide.
US 5,475, and 077 to have introduced with KOH be that catalyzer will encircle the dimethyl siloxane ring-opening polymerization, feed the method for water vapour with the air in the reactor and other gas displacements after 30 minutes.Under 170 ℃, 315 mmhg pressures, the airtight maintenance of reactor 30 minutes adds neutralizing agent ethylene chlorhydrin or other subsequently, and sylvite and the precipitation in the reactant that generates that will neutralize then removed, and hydroxyl polysiloxane molecule amount is regulated by the control water vapour pressure.This method is a discontinuous method.
US 4,780,519 and US 5,173,558 to have introduced with silanol potassium be that catalyzer, the silica-based acetic ester of dimethyl vinyl are the method for neutralizing agent.Hydroxy radical content in the polymkeric substance is controlled by water vapour pressure in the controlling reactor in polymerization process.This method is not to be used to produce the hydroxyl polysiloxane, but is used to produce the polysiloxane of other bigger group end capping of molecular weight, reduces the content of hydroxyl simultaneously with the method for control water vapour pressure, to enhance product performance.
US 4,551, and 515 have introduced the method for continuous production organopolysiloxane.Mixed methylcyclosiloxane and chain termination agent must dewater before adding catalyzer in this method; The silanol potassium that contains 5%KOH is catalyzer, and silica-based phosphoric acid ester is a neutralizing agent.This method is used to produce full-bodied polysiloxane, rather than the hydroxyl polysiloxane.
US 4,250, and 290 have introduced a kind of technology of continuous production hydroxyl polysiloxane.Polyreaction is carried out in static mixer, and catalyzer is the siloxanes potassium alcoholate, and temperature of reaction is 160-190 ℃, and neutralizing agent is silica-based phosphoric acid ester, and polymerization pressure is 1.17Mpa; If water is chain termination agent, then add at twice, the front end at polymeric part adds water for the first time, amount is 100ppm-500ppm, at polymerization rear end Jia Shui, primary water is mainly used in the growth of the viscosity of controlling polymers for the second time, to guarantee the mixed effect of static mixer; Secondary water is used for regulating the total amount of water.Product viscosity is 0.5-500Pa.s.System pressure is 170Psig, promptly is equivalent to 1.17Mpa, is pressurized conditions operation down, thereby higher to equipment requirements, and production cost is also higher.Japan, spy open flat 5-43,694 methods of being introduced and above-mentioned resemble process.
In sum, the synthetic method of hydroxyl polysiloxane can be selected different catalyzer, neutralizing agent and raw material, generally believe better as catalyzer with potassium hydroxide, raw material adopts ring body more, the neutralizing agent range of choice is corresponding bigger, but mentioned method has following problem in the document: production method has uses interrupter method, can not form the continuous process flow process, only be confined to be unfavorable for industrialization in laboratory or the small mode scope; Continuous process needs to carry out under pressurized conditions, and is relatively harsher to equipment requirements, is unfavorable for reducing production costs.
Summary of the invention
The purpose of this invention is to provide a kind ofly under normal pressure, carry the steam method secretly with nitrogen, potassium hydroxide is made the continuous process of the synthetic α of catalyzer, alpha, omega-dihydroxy polydimethyl siloxane.
The invention provides a kind ofly under normal pressure, adopt potassium hydroxide to make catalyzer, the continuous process with the synthetic α of steam method, alpha, omega-dihydroxy polydimethyl siloxane comprises the steps:
(A) methyl cyclosiloxane and potassium hydroxide carry out polyreaction in polymeric kettle, and polymerization temperature is 130-170 ℃;
(B) be in the neutralizing agent and polymerisate with silica-based phosphoric acid ester, neutral temperature is 100-160 ℃;
(C) remove low molecule and unreacted ring body in the neutralized reaction product, taking off low temperature is 170-190 ℃, takes off low vacuum 0.08-0.10Mpa, obtains α, alpha, omega-dihydroxy polydimethyl siloxane.
Concrete operations are as follows:
The methyl cyclosiloxane is pressed in the batching still and after catalyzer stirs, is pressed into feed chamber with nitrogen through test tank, enters polymeric kettle continuously after the spinner-type flowmeter metering, carries steam secretly with nitrogen and enters polymeric kettle continuously, carries out polyreaction.During hydroxyl polysiloxane after the polymerization is squeezed into continuously with the single pole spiral pump and still, during the silica-based phosphoric acid ester of neutralizing agent enters continuously and still, the siloxane polymer after the neutralization enters and takes off low still, removes low molecule and unreacted ring body under vacuum condition.Take off polymkeric substance after low through packing, be α, alpha, omega-dihydroxy polydimethyl siloxane finished product.
The preferred 140-160 of polymerization temperature among the present invention ℃; The preferred 120-140 of neutral temperature ℃
The methyl cyclosiloxane among the present invention and the weight ratio of potassium hydroxide are 100: (10-15).
The tank reactor that polymerization reactor of the present invention stirs for band.The used reactor of neutralization reaction is a static mixer.
In the polymeric kettle residence time of reactant make polyreaction after unreacted methyl cyclosiloxane be less than 12-14%.
The methyl cyclosiloxane that the present invention uses is colourless transparent liquid, neutrality, and no bromine flavor, nontoxic, flammable, two sense chain link content (molar percentage) 〉=99.99%, no free-water, density is 0.970-0.980.
The α, the alpha, omega-dihydroxy polydimethyl siloxane range of viscosities that obtain by the inventive method are 5-80Pa.s.
The continuation method of the down synthetic α of a kind of normal pressure provided by the invention, alpha, omega-dihydroxy polydimethyl siloxane, the continuous process that has overcome prior art needs to carry out under pressurized conditions, and is relatively harsher to equipment requirements, is unfavorable for the shortcoming that reduces production costs.The present invention simultaneously adopts the method for nitrogen water entrainment to make stable operation of the present invention, is easy to control.This processing method is simple, mild condition, and technical indicator is outstanding, and not harsh to the reactor requirement, continuity is better, and security is higher.
Embodiment
The invention will be further described below by embodiment.
Embodiment one
The methyl cyclosiloxane is pressed in the batching still through test tank, after the adding potassium hydroxide catalyst stirs, be pressed into feed chamber, after the spinner-type flowmeter metering, enter polymeric kettle continuously with given pace with nitrogen, water is done carrier gas with nitrogen after the vaporizer vaporization, enter polymeric kettle continuously with given pace.Under 150 ℃, carry out polyreaction, leave polymeric kettle then, during hydroxyl polysiloxane after the polymerization is squeezed into continuously with the single pole spiral pump and still, during the silica-based phosphoric acid ester of neutralizing agent enters continuously with certain speed and still, neutral temperature is 130 ℃, siloxane polymer after the neutralization enters and takes off low still, 180 ℃ ,-remove low molecule and unreacted ring body under the 0.096Mpa.Other processing condition such as following table (1,2,3 are respectively three kinds of differential responses conditions).
| 1 | 2 | 3 | |
| Methyl cyclosiloxane feeding rate (l/h) | 35 | 35 | 35 |
| Potassium hydroxide feeding rate (kg/s) | 3.40 | 3.40 | 3.40 |
| Silica-based phosphoric acid ester feeding rate (kg/s) | 18 | 18 | 18 |
| Working pressure | Normal pressure | Normal pressure | Normal pressure |
| The residence time (h) nitrogen flow rate (m 3/ h) introducing speed (l/h) viscosity (Pas) transformation efficiency (%) fugitive constituent (%) of water | 2 0.5 0.60 13.80 85.00 1.69 | 2 0.5 0.72 7.80 85.58 1.64 | 2 0.5 0.96 4.84 86.87 1.56 |
Embodiment two
Operational process of craft such as example one.Polymerization temperature is 155 ℃, and neutral temperature is 150 ℃, and taking off low temperature is 185 ℃, takes off low pressure and is-0.096Mpa other processing condition such as following table (1,2 are respectively two kinds of differential responses conditions).
| 1 | 2 | |
| Introducing speed (l/h) nitrogen flow rate (m of the silica-based phosphate feed rate of methyl cyclosiloxane feed rate (l/h) potassium hydroxide feed rate (kg/s) (kg/s) the operating pressure time of staying (h) water3/ h) viscosity (Pas) transformation efficiency (%) fugitive constituent (%) | 35 3.40 18 normal pressures 2 0.96 0.5 5.26 86.10 1.56 | 35 3.40 18 normal pressures 2 0.96 1.0 5.13 89.30 1.85 |
Embodiment three
Operational process of craft such as example one.Polymerization temperature is 160 ℃, and neutral temperature is 155 ℃, and taking off low temperature is 190 ℃, takes off low pressure and is-0.095Mpa other processing condition such as following table (1,2 are respectively two kinds of differential responses conditions).
| 1 | 2 |
| Introducing speed (l/h) catalyst amount (ppm) viscosity (Pas) conversion ratio (%) fugitive constituent (%) of the silica-based phosphate feed rate of methyl cyclosiloxane feed rate (l/h) (kg/s) the operating pressure time of staying (h) water | 35 18 normal pressures 2 0.96 19 4.82 77.25 1.64 | 35 18 normal pressures 2 0.96 27 5.24 86.43 1.42 |
Claims (5)
- One kind under normal pressure, adopt potassium hydroxide to make catalyzer, the continuous process with the synthetic α of steam method, alpha, omega-dihydroxy polydimethyl siloxane comprises the steps:(A) methyl cyclosiloxane and potassium hydroxide carry out polyreaction in polymeric kettle, and polymerization temperature is 130-170 ℃;(B) be in the neutralizing agent and polymerisate with silica-based phosphoric acid ester, neutral temperature is 100-160 ℃;(C) remove low molecule and unreacted ring body in the neutralized reaction product, taking off low temperature is 170-190 ℃, takes off low vacuum 0.08-0.10Mpa, obtains α, alpha, omega-dihydroxy polydimethyl siloxane.
- 2. the described method of claim 1 is characterized in that polymeric reaction temperature wherein is 140-160 ℃.
- 3. the described method of claim 1 is characterized in that neutral temperature wherein is 120-140 ℃.
- 4. the described method of claim 1, it is characterized in that wherein the methyl cyclosiloxane and the weight ratio of potassium hydroxide be 100: (10-15).
- 5. the described method of claim 1, it is characterized in that reactant residence time in the polymeric kettle wherein make polyreaction after unreacted methyl cyclosiloxane be less than 12-14%.
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Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101210074B (en) * | 2007-12-24 | 2010-11-10 | 中昊晨光化工研究院 | Method for producing alpha, omega-dihydroxy polydimethyl siloxane |
| CN102127227B (en) * | 2010-12-27 | 2013-03-13 | 蓝星化工新材料股份有限公司江西星火有机硅厂 | Low viscosity hydroxyl terminated polysiloxane and preparation method thereof |
| CN102093561B (en) * | 2010-12-27 | 2013-05-29 | 蓝星化工新材料股份有限公司江西星火有机硅厂 | High-efficiency catalyst used for preparing high ring 107 glue and preparation method thereof |
| CN103059303B (en) * | 2012-12-25 | 2015-05-06 | 蓝星化工新材料股份有限公司江西星火有机硅厂 | Preparation method of hydroxyl blocking polydimethylsiloxane |
| CN103122069B (en) * | 2013-02-28 | 2015-06-24 | 浙江大学 | Telomerization-free method and device for continuously preparing polysiloxane from cyclosiloxane |
| CN104140529A (en) * | 2014-07-10 | 2014-11-12 | 何少云 | Preparation method of high-viscosity silicone oil |
| CN110606953A (en) * | 2019-09-26 | 2019-12-24 | 唐山三友硅业有限责任公司 | Low-viscosity hydroxyl-terminated vinyl methyl silicone oil and continuous preparation method thereof |
| CN110655049B (en) * | 2019-10-09 | 2022-02-01 | 新纳奇材料科技江苏有限公司 | Preparation method of phosphonitrile chloride catalyst and application of phosphonitrile chloride catalyst in preparation of alkoxy-terminated polysiloxane |
| CN112831049A (en) * | 2021-03-09 | 2021-05-25 | 浙江新安化工集团股份有限公司 | Preparation method of alpha, omega-dihydroxy polydimethylsiloxane |
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| CN1292260A (en) * | 1999-09-29 | 2001-04-25 | 欧莱雅 | Detergent composition made from keratin material |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1292260A (en) * | 1999-09-29 | 2001-04-25 | 欧莱雅 | Detergent composition made from keratin material |
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