CN1154706A - Polymerization of ethylenic chloride with inorganic salt - Google Patents

Abstract

Process for preparing a polymer or copolymer from polymerizable monomers by suspension polymerization whereby foam formation during the removal of residual monomers is inhibited, which process comprises adding at least one salt of an inorganic acid having an anionic valency of at least 2 to the polymer slurry prior to the removal of the residual monomer.

Description

Use the polymerization of the chlorination alkene of inorganic salt

The present invention relates to a kind of preparation method of polymkeric substance, can be suppressed at by this method that foamy forms when removing residual monomer.

There are three kinds of common typical zolymerization methods.A kind of monomer of polymerization or two or more monomeric homogeneous mixtures (as single liquid phase) be not when forming solid-state polymer blocks material in the presence of having solvent or thinner, and this method is called " body " or " homogeneous phase " polymerization.When being scattered in the latex bead dispersions that forms the polymer particulate in the water when the miscible monomer of one or more water with water-soluble catalyst or water soluble starter by " tensio-active agent " or emulsifying agent, this method is called " emulsion " polymerization.The third method comprises use to disperse or suspension agent, with monomer and water miscibility and mix with water with the catalyzer or the initiator of monomer solubility, by under the temperature of known induced polymerization ceaselessly stirring keep dispersion or suspensoid.The present invention relates to this third method.This method is called as " suspension " polymerization.

In suspension polymerization, starting monomer is suspended in the aqueous phase that comprises suspension agent and polymerization starter.Cause and under heating and stirring, carry out usually the polymerization of starting monomer.Continue polymerization till reaching required monomeric transformation efficiency.Products therefrom is water suspension or dispersion, all contains abundant residues monomer and other impurity volatile, non-monomeric form, as organic solvent.In many cases, need remove residual monomer and impurity in all these suspension systems basically.

Traditional way is, by simple emptying reactor, or heating and/or decompression reactor are removed residual monomer.But, this remove residual monomer during, in dispersion system, form a large amount of foams, this makes the monomeric process very slowly that becomes of removing.Foam also can be taken away polymer solids and enter vacuum system, causes line clogging.

A kind of polymerization process that foam forms that suppresses during removing residual monomer need be provided.

The invention provides and a kind ofly prepare the method for polymkeric substance or multipolymer from polymerisable monomer by suspension polymerization, this method can be suppressed at residual monomer remove during foamy form, this method comprises:

(A) provide polymeric monomer intermixture, have the water that comprises water soluble dispersing agent and comprise the monomeric monomer of at least a suspension polymerization mutually;

(B) the polymerization polymerisable monomer forms polymer slurries;

(C) add the salt of at least a mineral acid in the polymer slurries in step (B), the preferred anionic valence state is at least the salt of 2 mineral acid;

(D) from the polymer slurries of step (C), remove residual monomer;

(E) dry this slurry forms polymer composition.

Present method is applicable to that by suspension polymerization polymkeric substance and multipolymer the foam that can be suppressed at during residual monomer is removed by this method forms.The suspension polymerization that is particularly useful for vinylidene chloride and/or vinylchlorid forms in vinylidene chloride polymkeric substance and the vinyl chloride-base polymer, and the foam when suppressing to remove residual monomer forms.

Preferably, be applicable to that polymkeric substance of the present invention is (1) 1,1-Ethylene Dichloride polymkeric substance, by 1,1-Ethylene Dichloride monomer or by being mainly 1,1-Ethylene Dichloride monomer and a small amount of for the monomeric polymerization of mixtures of the undersaturated copolymerization with it of olefinic forms and (2) vinyl chloride-base polymer is by vinyl chloride monomer or by being mainly vinyl chloride monomer and forming for the monomeric polymerization of mixtures of the undersaturated copolymerization with it of olefinic on a small quantity.

Term " vinylidene chloride polymkeric substance " and " vinyl chloride-base polymer " comprise homopolymer, multipolymer and the terpolymer of vinylidene chloride and vinylchlorid respectively.

For the vinylidene chloride polymkeric substance, the polymeric vinylidene chloride monomer of significant quantity accounts for the 60-100% weight of polymkeric substance usually.

For vinyl chloride-base polymer, the polymeric vinyl chloride monomer of significant quantity accounts for the 60-100% weight of polymkeric substance usually.

Can be with 1, the suitable ethylenically unsaturated monomer of 1-Ethylene Dichloride monomer or vinyl chloride monomer copolymerization comprises vinylchlorid or 1 respectively, 1-Ethylene Dichloride and other monomer such as alkyl acrylate, alkyl methacrylate, vinylformic acid, methacrylic acid, methylene-succinic acid, vinyl cyanide and methacrylonitrile.Usually select each alkyl to have the alkyl acrylate and the alkyl methacrylate of 1 to 8 carbon atom in alkyl acrylate and the alkyl methacrylate.Preferred each alkyl has the alkyl acrylate and the alkyl methacrylate of 1 to 4 carbon atom.Most preferably methyl acrylate, ethyl propenoate and methyl methacrylate.

The water-soluble dispersion or the suspension agent that are suitable for include but not limited to water miscible alkyl or hydroxyalkyl alkyl cellulose ether and composition thereof, and wherein alkyl contains 1 to 6 carbon atom, and hydroxyalkyl contains 2 to 4 carbon atoms.The example of water-soluble dispersion of this class or suspension agent is an ether of cellulose, as methylcellulose gum, carboxymethyl cellulose, methyl carboxymethyl cellulose, methyl carboxyethyl cellulose, hydroxyethyl carboxymethyl cellulose, Type 3U and Vltra tears.Ether of cellulose is well known in the art, and the reaction of mixture that can be by soda cellulose and methyl chloride and propylene oxide prepares.The ether of cellulose product of gained contains the methoxyl group of common amount to provide water-soluble, be the hydroxypropyl substituting group in the molecule of the methoxy content of 16-35% and relatively small amount, 0.05 to 2 this class group representing each dehydrated glucose unit is with the gelation point of the aqueous solution that influences ether of cellulose.Can use the ether of cellulose of any viscosity grade.Here used viscosity grade is meant 2% viscosity in aqueous solution of the ether of cellulose that the Ubbelohde kapillary by suitable dimension records under 20 ℃.Ether of cellulose preferably has the viscosity of 3～300,000 centipoise (CPS).

The consumption of water-soluble suspension agent is the 0.001-1% weight of monomer weight, preferred 0.05-1% weight.

Being expected to be used for suitable initiator of the present invention includes but not limited to: superoxide, as hydrogen peroxide, peroxidation isopropyl percarbonate, lauroyl peroxide, tert-butyl hydroperoxide; Azo-compound, as 2,2 '-Diisopropyl azodicarboxylate or its mixture.

The consumption of initiator is preferably the 0.01-1.0% weight of monomer weight, more preferably 0.1-0.7% weight, most preferably 0.2-0.5% weight.

The salt of mineral acid (hereinafter referred to as " inorganic acid salt ") water soluble under working concentration.Solubleness is subjected to the influence of other component in temperature, pressure, PH and the composition.These factors are well known by persons skilled in the art, and they can easily be measured by normal experiment influence of the present invention.

The inorganic acid salt that is suitable for comprises alkali and alkali earth metal phosphate, alkali and alkaline earth metal borate, alkali and alkaline earth metal carbonate, alkali and alkali metal bicarbonates, alkali and alkaline-earth metal phosphuret-(t)ed hydrogen and composition thereof.The molysite and the aluminium salt that also have boric acid, phosphoric acid, carbonic acid, sulfuric acid, Tripyrophosphoric acid, phosphorus hydracid and tetra-sodium that are suitable for.Preferred inorganic acid salt is tetrasodium pyrophosphate, sodium hypophosphate, trisodium phosphate, sodium orthophosphate, sodium polyphosphate, potassium hypophosphate, potassium pyrophosphate, potassium orthophosphate, potassium polyphosphate and composition thereof.Most preferred inorganic acid salt is a tetrasodium pyrophosphate.

The inorganic acid salt that the present invention uses can prepare by currently known methods.Only be the illustrative purpose, the technology of preparation tetrasodium pyrophosphate is disclosed in The Merck Index, the 10th edition (1983).

The usage quantity of inorganic acid salt is the 0.001-5% weight of the weight of monomer mixture, preferred 0.0015-3% weight, more preferably 0.01-1.5% weight, most preferably 0.02-0.5% weight.

By suspension polymerization vinylidene chloride polymkeric substance and vinyl chloride-base polymer is known in the art.Except this paper point out especially, polymerizing condition (for example, temperature and stirring) is a condition commonly used in vinylidene chloride or the chloroethylene polymerization.Advantageously, in preparation during water, before initiator, softening agent and other suitable additive (as sequestrant and antioxidant) add, in reactor, add about 3/4 required water of polymerization.The addition sequence of water component helps to keep the polymerization that monomer is scattered in the suspension system in the water.

Usually, when monomer is added to water (monomer is scattered in water), with mixture stir and basic oxygen free condition under be heated to 25 ℃ to 95 ℃ temperature and continue enough for some time so that the required monomer transformation efficiency to polymkeric substance to be provided.Monomer to the transformation efficiency of polymkeric substance usually at 50-99%.

After polymerization is finished, formed the aqueous-phase suspending body or the slurry of polymkeric substance or multipolymer.Do not contain monomeric slurry in order to form, preferably at first by with reactor emptying to normal pressure reactor heating to 95 ℃ and residual monomer is removed simultaneously.Then slurry is transferred in batches in the stripping tower at 90 ℃ the residual monomer coupling vacuum stripping.The emptying reactor, with the slurry mechanical transmission during stripping tower and the coupling vacuum stripping residual monomer, suspension agent that still exists in solution and tensio-active agent have increased foamy and have formed and make foam stabilizationization by surperficial pectisation.The foam of this stabilization is brought resin clip susceptor (knockout pot) into, is transferred pipeline and reject dump just.

Surprisingly, found before removing residual monomer, at least a inorganic acid salt to be added in the polymer slurries, can suppress foamy and form.Although do not trend towards making an explanation theoretically, think that inorganic acid salt has reduced the gelation temperature of suspension agent, this makes suspension agent produce sedimentation, makes it to increase foamy and forms and the stabilization foam." gelation temperature " is described in article " hot glue of methyl and Vltra tears coagulates performance ", author N.Sarkar, Journal of Applied Polymer Science, Vol.24,1073-1087 (1979).

If the polymkeric substance of the inventive method preparation is the vinylidene chloride polymkeric substance, inorganic acid salt also can in and all hydrochloric acid of between polymerization period, forming by the monomeric dehydrochlorination of vinylidene chloride.

Inorganic acid salt can be added to polymer slurries with solid form or with the dilute aqueous soln form.Can be before polymer slurries being transferred to monomer stripping container, to be added in the aggregation container, or when polymer slurries is heated to the temperature that is enough to the coupling vacuum stripping residual monomer, be added in the monomer stripping container.

After removing residual monomer,, enter in the whizzer and dewater the slurry cooling, and collected polymer, further dry.

Although The present invention be directed to embodiment preferred is described, promptly prepare 1, the suspension polymerization of 1-Ethylene Dichloride and vinyl chloride-base polymer, the present invention also is fit to prepare other polymkeric substance and prepare multipolymer from these monomers and other unsaturated monomer from for example following monomer: acrylate, vinylbenzene and Vinylstyrene, vinyl-acetic ester, tetrafluoroethylene, a chlorotrifluoroethylene.

By following examples the present invention is further described.Embodiment only is the purpose of explanation, should not be construed as the restriction scope of the invention.Except as otherwise noted, all umber and percentage ratios all are the weight number.Embodiment 1

From monomer mixture, prepare polymer composition by suspension polymerization.To 10,000 gallon of band stirs in the polymerization reactor and adds 33,000 pound of softening water, 3% solution of 140 pounds of sad tert-butyl esters of mistake (t-BPO), 2 pounds of butylhydroxy toluenes (BHT) and 564 pounds of tetrasodium pyrophosphate (TSPP) (by in and the dehydrochlorination of vinylidene chloride monomer produces between polymerization period HCl control pH value).The mixture that is stirring in reactor adds 3235 pounds of methyl acrylates (MA) and 34450 pounds of vinylidene chlorides (VDC) monomer.Stop stirring, add the METHOCEL of 4300 pounds of about 1% concentration then ^TM(trade mark of Dow Chemical) ether of cellulose solution and 10,200 pounds of softening waters.Reopen to stir and be scattered in the suspensoid in the water and generate monomer droplet to form organism.The MA/VDC monomer mixture by charging step exhaust at utmost to reduce existing of noble gas and oxygen in the reactor.Reactor is heated to about 73 ℃ temperature.After polymerization began, temperature rose to 86 ℃, continued about 8 hours of polymerization.

MA/VDC residual monomer removal process is from the emptying step.About 30psig is reduced in reactor pressure initial emptying in 30 minutes, and control emptying speed reduces foam with minimum degree.During initial emptying, reactor content is heated to 95 ℃ from 80 ℃.After initial emptying is finished, with reactor content pump to 15, in the 000 stripping container that stirs.When polymer slurries is transferred in the stripping container, 1450 pounds of 3%TSPP solution are added in the reactor.Before all materials all were sent to the stripping container, temperature had rolled back 80 ℃, but content continues to add steam and set up the balance of driving away monomeric boiling speed to boiling point in the direct injecting steam reheat stripping tower.In addition, per hour the injection of 35 to 45 pounds nitrogen gas stream and 8 to 10psia vacuum help the stripping operation.Not observing foam in stripping operating period forms.Comparative example A and B

In the comparative example A, prepared polymer composition as embodiment 1, but in reaction slurry, do not added 1450 pounds of 3%TSPP solution in the stripping stage.In Comparative Examples B, adopt method, but after residual monomer is removed, add 1450 pounds of 3%TSPP solution again with embodiment 1.In both of these case, the foam of having observed nonconforming amount forms.

Claims (13)

1, prepare the method for vinylidene chloride polymkeric substance or vinyl chloride-base polymer by suspension polymerization from polymerisable monomer, this method can be suppressed at residual monomer remove during foamy form, this method comprises:

(A) provide polymeric monomer intermixture, have the water that comprises water soluble dispersing agent and comprise the monomeric monomer of at least a suspension polymerization mutually;

(B) the polymerization polymerisable monomer forms the slurry of polymkeric substance and residual monomer;

(C) add the salt that at least a negatively charged ion valence state is at least 2 mineral acid in the polymer slurries that in step (B), forms behind the monomer polymerization;

(D) from the polymer slurries of the inorganic acid salt that contains step (C), remove residual monomer;

(E) dry this slurry forms exsiccant polymkeric substance or multipolymer.

2, the process of claim 1 wherein that step (D) comprises applies vacuum to flash out residual monomer to polymer slurries.

3, the method for claim 1, wherein 1,1-Ethylene Dichloride polymkeric substance is from 1,1-Ethylene Dichloride monomer or from the preparation of the mixture of vinylidene chloride and at least a other monomer or vinylchlorid, alkyl acrylate, alkyl methacrylate, vinylformic acid, methacrylic acid, methylene-succinic acid, vinyl cyanide and methacrylonitrile.

4, the method for claim 1, wherein vinyl chloride-base polymer is from vinyl chloride monomer or from the preparation of the mixture of vinylchlorid and at least a other monomer or vinylidene chloride, alkyl acrylate, alkyl methacrylate, vinylformic acid, methacrylic acid, methylene-succinic acid, vinyl cyanide and methacrylonitrile.

5, the process of claim 1 wherein that the content of inorganic acid salt is the 0.001-5% weight of monomer mixture gross weight.

6, the method for claim 5, wherein the content of inorganic acid salt is the 0.005-3% weight of monomer mixture gross weight.

7, the method for claim 6, wherein the content of inorganic acid salt is the 0.01-1.5% weight of monomer mixture gross weight.

8, the method for claim 7, wherein the content of inorganic acid salt is the 0.02-5% weight of monomer mixture gross weight.

9, the process of claim 1 wherein that inorganic acid salt is alkali or alkali earth metal phosphate, alkali or alkaline earth metal borate, alkali or alkaline earth metal carbonate, alkali or alkali metal bicarbonates, alkali or alkaline-earth metal phosphuret-(t)ed hydrogen, alkali or alkaline-earth metal alkylphosphonic, alkali or alkaline-earth metal aryl orthophosphate, alkali or alkaline-earth metal alkyl phosphite, alkali or alkaline-earth metal aryl phosphite, alkali or alkaline-earth metal alkylsulfonate or alkali or alkaline-earth metal arylsulphonate and composition thereof.

10, the process of claim 1 wherein that inorganic acid salt is the molysite and the aluminium salt of mineral acid, mineral acid wherein is boric acid, phosphoric acid, carbonic acid, sulfuric acid, Tripyrophosphoric acid, diphosphanetetroic acid or tetra-sodium.

11, the process of claim 1 wherein that inorganic acid salt is tetrasodium pyrophosphate, sodium hypophosphate, trisodium phosphate, sodium orthophosphate, sodium polyphosphate, potassium hypophosphate, potassium pyrophosphate, potassium orthophosphate, potassium polyphosphate and composition thereof.

12, the process of claim 1 wherein that suspension agent is water-soluble alkyl or hydroxyalkyl alkyl cellulose ether and composition thereof, alkyl wherein contains 1 to 26 carbon atom, and hydroxyalkyl wherein contains 2 to 4 carbon atoms.

13, the suspension agent that the process of claim 1 wherein is methylcellulose gum or Vltra tears.