CA1161195A - Process for the manufacture of suspension polyvinyl chloride free of dust-fine particles and having improved properties - Google Patents
Process for the manufacture of suspension polyvinyl chloride free of dust-fine particles and having improved propertiesInfo
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- CA1161195A CA1161195A CA000364216A CA364216A CA1161195A CA 1161195 A CA1161195 A CA 1161195A CA 000364216 A CA000364216 A CA 000364216A CA 364216 A CA364216 A CA 364216A CA 1161195 A CA1161195 A CA 1161195A
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- suspension
- weight
- dust
- polyvinyl chloride
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F14/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen
- C08F14/02—Monomers containing chlorine
- C08F14/04—Monomers containing two carbon atoms
- C08F14/06—Vinyl chloride
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- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
- Polymerisation Methods In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A process for the production of suspension polyvinyl chloride free of dust-fine particles and having improved properties by polymerizing vinyl chloride under suspension polymerization conditions employing at least one water-soluble polyvinyl alcohol prepared by partial solvolysing polyvinyl acetate in an alcoholic solution in the presence of an acid catalyst. The resulting polyvinyl chloride is substantially free of dust-fine particles and has improved thermostability.
A process for the production of suspension polyvinyl chloride free of dust-fine particles and having improved properties by polymerizing vinyl chloride under suspension polymerization conditions employing at least one water-soluble polyvinyl alcohol prepared by partial solvolysing polyvinyl acetate in an alcoholic solution in the presence of an acid catalyst. The resulting polyvinyl chloride is substantially free of dust-fine particles and has improved thermostability.
Description
168.128-Can.
The subject of the presen~ invention is a process for the manufacture of polyvinyl chloride ~PVC3 free of dust-fine particles and having improved properties by homopolymerizing or copolymerizing vinyl chloride (VC), optionally with up to 40% by weight, based on the VC~ of other copolymeriæable vinyl compounds, according to the suspension polymerization process, in the presence of oil-soluble free-radical initiators, dispersion stabilizers and, optionally, other polymerization auxiliaries, the process being characterized in that, as dispersion sta~ilizer, there is employed one or more water-soluble polyvinyl alcohol~s~ (PVAL) which has or have heen manufactured by partially solvolysing polyvinyl acetate (PVAC) in an alcoholic solution in the presence of an acid catalyst.
The abbreviation PVC is intended herein to mean vinyl chloride homopolymers and copolymers of vinyl chloride with up to 40% by weight, based on the VC content of one or more ethylenically-unsaturated monomers that are cop~ly-merizable therewith. Such other monomers are, for example, vinyl esters of aliphatic, linear and/or branched, saturated C2-C18 aliphatic carboxylic acids; such as vinyl ac~tate, vinyl propionate, vinyl butyrate; olefins/ particularly lower l-alkenes, such as ethylene, propylene; esters of unsaturated acids, such as the Cl-C18 alkyl estexs of lower alkenoic and alkendioic acids~ such as acrylic acid esters, methacrylic acid esters, maleic acid esters and fumaric acid esters of Cl-C18 alcohols; and unsaturated ~ ~ 61 ~ ~
acids, part~icularly lower alkenoic acids such as acrylic acid, methacrylic acid, itaconic acid and crotonic acid;
maleic acid and fumaric acid and semiesters thereof. The abbreviation PVC also includes graft polymers of VC and up to 50% by weight, based on the VC, of a polymeric substrate of one or more of the monomers mentioned.
It is known, fo~ example, from European P~atent ~pplication No. EP 0 002 ~61, as well as German Published Application DE~OS No. 26 53 087, to manufacture VC homo-polymers and copolymers in the presence of PVAL, whichgenerally means partially saponified PVAC.
According to both specifications, the suspension polymerization of the monomers is carried out in the presence of a combination of a water-soluble, so called primary, protective colloid with a water-insoluble, so-called secondary, protective colloid. For the manufacture of an acceptable S-PVC, the secondary protective colloid cannot be used in these processes without the primary protective colloid.
According to the above-mentioned European Patent Application, a product having a high porosity, large BET
surface area, narrow particle size distribution and good plasticizer acceptance is obtained and, after processing, it shows only a few "fish eyes".
The process of the above-mentioned German Published ~pplication yields polymers having improved porosity, low residual monomer content, a crumbly structure and a high bulk density.
These properties are only achieved by the combina-tion of a customary water-soluble protective colloid (until now the world market has offered no PVAL
~ 16~9~
manufactured by acid hydrolysis that would be suitable or manufacturing S-PVC) with the water-insoluble secondary protective colloid essential to these applications.
It is mentioned in the European Pa~ent Application that PVAL can be manufactured by solvolysing PVAC in an acidic or basic pH range, but the manufacture of the secondary protective collold, which is described in more detail, is effected exclusively in an alkaline range.
The low degree of hydrolysis of the water-insoluble PVAC is achieved either by early termination of the solvoly-sis, which, however, according to the European Patent Appli-cation, produces avery inhomogeneous poor protective colloid because this reaction takes place very quickly, or by com~
plicated saponification conditions which are described in detail in the above-mentioned specification.
The German Published Application makes reference only to the possibility of manufacturing the secondary protective colloid by acid-catalyzed or alkali-catalyzed saponification which, however, as described above, must be terminated early. Further comments in the above-mentioned German Published Application, for example that the polymer manufactured as described therein, which adheres to the reaction walls and crumbles to a relatively great extent, indicate that the polymer produced contains a large propor-tion of dust-fine particlesu German Patent Application 27 02 771 uses vinyl acetate/vinyl alcohol block copolymers as a secondary pro-tective colloid in the suspension polymerization of VC, in order further to improve the morpholo~y and grain structure of PVC, which are both areas in need of improve-ment. Because they too are complicated to manufacture, however, such block copolymers are unsuitable for use as a protective colloid in the present-day large-scale produc-tion of PVC.
No process is known from the state of the art:that, because of its simplicity, is suitable for the large-scale production of PVC and, at the same time, yields products which are free of dust-fine particles and have improved properties.
An object of the present invention is the production of suspension polyvinyl chloride which is free of dust-fine particle.s and has improved properties.
Another object of the present invention is the development of an improvement in the process fox the produc-tion of suspension-polymerized polyvinyl chlori~e comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to ~0% by weight of monomers copolymerizable with vinyl chloride under suspen-sion polymerization conditions in the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 3 to 8 and a temperature of from 30C to 70C for a time su~ficient to effect polymerization and recovering poly-vinyl chloride, the improvement consisting of employing at least one water-soluble polyvinyl alcohol produced by partially solvolysing polyvinyl acetate in an alcoholic solution in the presence of an acid catalyst, as said at least one dispersion stabilizer, and recovering suspension-polymerized polyvinyl chloride which substantially is free of dust-fine particles and has improved thermostability.
l l 61195 I These and other objects of the invention will become more apparent as the description thereof proceeds~
Surprisingly, it has now been discovered that when ¦ carrying out the process according to the invention in the I presence of a water-soluble PVAL that has been manuactured by partially solvolysing PVAC in alcoholic solution with the addition of an acid catalyst, as a single protective colloid, it is possible to produce a VC polymer without fines and having improved properties. In accordance with the process according to the invention, it is possible to obtain, in a technically simple manner, a PVC which is free of dust-fine particles r which previously could }lOt be obtained without sieving.
More particularly, the present invention relates to the improvement in the process for the production of suspension-polymerized polyvinyl chlorlde comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 40% by weight of monomers copolymeri~able with vinyl chloride under suspen-sion polymerization conditions in the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 1 3 to 8 and a temperature of from 30C to 70C for a time I sufficient to effect polymerization and recovering pol~-I vinyl chloride, the improvement consisting of employing at I least one ~ater-soluble polyvinyl alcohol produced by partially solvolysing polyvinyl acetate in an alcoholic l 1~11~5 solution ;n the presence of an acid catalyst, as ~aid at least one dispersion stabilizer, and recove~ing suspension-polymerized polyvinyl chloxide which subs-~antially is free of dust~fine particles and has improved thermostability ;
as well as the suspension-polymerized polyvinyl chloride which is substantially free of dust-fine particles and has improved thermostability, produced by the aforesaid process.
In PVC processing, a content of dust (particles of dust fineness~ is undesirable for various reasons. ~part from causing inconvenience in the place of work when hand-ling the dust-produclng polymer, the incorporation by mixing o processing auxiliaries, such as plas~icizers, stabilizers, colorants and others, especially in he case of liquid auxiliaries and additives, is rendered more difficult inso-far as differing adsorption properties of fines and of correctly sized particles can lead to an inhomogeneous dis-tribution of these materials. The effect of such conditions is the formation of a coating in the mixer, problems in processing PVC and losses in the quality of the fini~hed article. Fines in PVC are also undesirable, however, in the case of pneumatic material transportation without which large-scale industry cannot operate today, since segrega-tion phenomena after the manner of an air separation can occur. In this manner, inhomogeneities that are difficult to control are caused within a type of product, and this also leads to serious processing problems.
The lack of fines in the PVC manufactured accord~
ing to the invention unexpectedly reduces encrus-tation of the walls of the autocla~e during polymerization, which is almost unavoidable when using known processes. It is thus possible, in a technically simple manner, to dispense with an additional encrustation inhibitor. The lat~er is often the cause of undesirable impurities in the polymer.
Finally, it has been shown that, after polymeriza-tion according to the invention has been completed, the required degassing for removing residual amounts of toxic monomer is rendered considerably simpler by the reduced foaming behavior of the suspension as compared with suspen-sion polymerization using conventional polyvinyl alcohols saponified with an alkali. As a result r it is possible to accelerate the degassing processl which results in a reduc-tion in the time required for working up, less thermal stress on the crude product, and consequently an increase in efficiency.
~ urprisingly, the product manufactured according to the invention also has an improved therrnostability as compared with products that have been manufactured in the conventional manner by suspension polymerization in the presence of PVAL saponified with an alkali.
The water-soluble PVAL used in the process accord-ing to the invention can be added to the aqueous phase ofthe polymerization mixture, preferably in quantities of from 0.02% to 1.0% by weight, based on the monomer content, before the beginning of the polymerization or all or part of the PVAL can be metered in during polymerization. Itist of course, possible additionally to use a secondary protec-tive colloid in quantities of up to a maximum of 1~ by weight, based on the monomer content, in order to achieve special effects. It is, however, preferable to use con-siderably less, for example less than 0.1% by weight, based on the monomer content. Such concomitant use o~ a secondary protective colloid is not, however, necessary for solving 1 J ~
the problem posed initially, of manufacturing a PVC free of dust-fine particles and having improved properties.
The PVAL used according to the invention may be manufactured, for example, as follows:
10 parts by weight of a PVAC of low to moderate viscosity (approximately 3 to approximately 30 mPas, as measured according to H~ppler in a 4~ by weight aqueous solution at 20C) are first dissolved, while being stirred, in 40 parts by weight of methanol. After heating to 60C, 0.5 part by weight of concentrated hydrochloric acid in 1 part by weight of methanol is added while stirring is con-tinued. The extent of the solvolysis now commerlcing is determined by the reaction time. The relationship between the length of the reaction and the degree of hydrolysis may be esta~lished by a few preliminary experiments. To make a qualitative test, the progress of the saponification can be observed using a test tube sample. If, on the addi-tion of plenty of water to the reaction sample, no precipi-tate is formed, then usually a saponification number of less than 400 has been reached, corresponding to a degree of hydrolysis of more than 55 mol~ With further saponifica tion, the test-tube sample becomes increasingly clear on the addition of water. The addition of 50 parts by weight of water to the reaction mixture and neutralization to p~I
~.5 to 7~0 stops the acid hydrolysis at the desired time.
Methanol and methyl acetate are extensively separated off by vacuum distillation, while the corresponding decrease in volume can be compensated for by the addition of water. The result is a clear colorless solution of polyvinyl alcohol in water which, after its degree of saponification and solids content have been determined, can be used in the ~ 1 ~1 19~
resulting Eorm for the suspension polyrneri~ation of vlnyl chloride accordiny to the pre~ent lnvention.
The manufacturiny conditions described above may, of course, be varied within a wide range without influencing the specific pro-tective co~loid properties of the PVAL
manufactured by acid hydrolysis, as long as the specified viscosity range and degree of hydrolysis are observed.
Higher concentrations of PVAC increase the viscosity of the methanolic solution, which must be such that the reaction mixture can still be stirredO The concentration of the PVAC can vary, for example, from approximately 10 to approximately 60 parts by weight per 100 parts by weight of Cl-C3 alkanol. The higher the viscosity of the PVAC, the lower the concentration is set. A variation in temperature is, of course, also possible. Lower temperatures usually lengthen the reaction time and considerably higher temperatures can lead to practical difficulties because of boiling occurring in the reactor. It is also possible to vary the concentration of the acid catalyst, for example, from 0.1 to 5 pa,ts by weight per 100 parts by weight of alcohol. The speed of solvolysis generally increases as the concentration of catalys-t increases, The desired catalyst action is, of course, not limited only to aqueous inorganic acids, particularly aqueous mineral acids such as hydrochloric aciA, hydrobromic acid, hydrofluoric acid, sulfuric acid, phosphoric acid, perchloric acid and mixtures thereof.
As far as it is possible and meaningful, these acids can also be used in anhydrous form Furthermore, it is also possible to use other acidically active inorganic and organic compounds as catalyst, for example, carboxylic acidsj sulfonic ac;ds, mgJ~ g _ -9 5~ ' and phosphonic aci`ds, Suitable acid catalysts may~ ~OX
example, ~e selected with re~erence to the tables in 'IPure and Applied Chemi~stry'l 1 (1960) 187 to 536 and ibid 20 (1969) 133 to 236.~ It is cri`tical that the pH value during solvolysis lies below 6.5~ especially below 5~ i`n order to ensure that the solvolysis takes place sufficiently qu~ckly.
After terminatin~ the solvolysis~ di~still;~n~ of~ the vola-tile oxganic compounds present in the reaction mixtu~e/ and taking up in water, the PVAL can be used in the proce~s accQrdi`ng to the invention. A preferred PVAL is one havIng a Viscosi`ty of from approximately 2 to 30 mPasr especially from 2 to 10 mPas~ as measured according to H~ppler in a 4~ by we~ght aqueous solution at 20C, and preferably having a degree of hydrolysis of ~rom ~pproximately 55 to 85 mol%, correspondi`n~ to a saponificatio~ number of fro~ approxi-mately 40a to approximately 1~5~
The process according to the invention is carried out in a manner known per se in the presence of oil-soluble (monomer-soluble) free-radical initiators or mixturés thereof~ such as organic peroxides or azo compounds, for example acyl peroxides, percarbonates, acyl cyclohexane-sulfonyl peroxides, peresters, azocarboxylic acid nitriles and the like, and, optionally, known polymerization auxil-iaries, it being possible for the concentrations of these compounds to lie within the generally customary ranges.
Suitable polymerization auxiliaries that may optionally be used are, for example, emulsifiers, buffer substances, molecular-weight regulators and encrustation inhibitors.
These auxiliaries are not essential for achieving the ad~antages according to the invention: their concomitant or non-concomitant use and the time, ~pe and quantity of ~ 3 ~
their addition are not decisive criteria and thus also do not represent limitations of the invention, as their opti-mum values can be determined by the expert in a few experiments. The polymerization reaction is preferably conducted at a pH of from 3 to 8 and at a temperature of from 30C to 70C, as is customary.
The following examples and comparison tests illus-trate the present invention in more detail without being limitative.
EXAMPLES
The products were analyzed by carrying out tests for sieve analysis, dust, pressing stability and furnace stability as described below. (ppm = parts by weight/106 parts by weight~
Sieve analysis:
. . . _ . . _ Alpine air jet sieve. (by Alpine AG, Augsburg, West Germany~
Dust test:
80 gm of a dried P~C sample were trickled through ~ a vertically mounted PVC tube of 1 ~ length and 25 mm diameter. The portion adhering to the wall of the tube as a result of electrostatic charge was weighed and its per-centage of the original weight determined.
Pressing stabilit~:
100 parts by weight o~ PVC were mixed with 50 parts by weight of di-2-ethylhexyl phthalate, 0.5 parts by weight of tribasic lead sulfate and 0.2 parts by weight of montan wax ~wax E), and processed on a roll mill for 2 minu-tes at 170C to form a rolled sheet. This rolled sheet was then pressed for 10 minutes at 180C or 190C to form a 1 mm thick pressed plate. The discoloration occurriny as a l q ~ 195 result of too little stabilization was measured colori-metrically according to German Industrial Standard DIN 6174.
In comparison with a measuring standard of unlimited trans-mission (measured value 100), decreasing numerical values indicate increasing discoloration.
Furnace stability:
In two recipes, A and B, as given in the Table, 1 mm thick rolled P~TC shee~s were produced by rolling for 10 minutes at 170C and were then subjected to a Matthis Thermotest at 190C. In this test, a PVC strip cut from the rolled sheet was drawn through a heating furnace at a constant speed. The distance in mm from the starting point to the beginning of a dark-brown coloration is a measure of the heat stability.
Comparison Test A
A 2-m agitating autoclave was charged ~ith the following components in the order specified 930 parts by weight of de-ionized water
The subject of the presen~ invention is a process for the manufacture of polyvinyl chloride ~PVC3 free of dust-fine particles and having improved properties by homopolymerizing or copolymerizing vinyl chloride (VC), optionally with up to 40% by weight, based on the VC~ of other copolymeriæable vinyl compounds, according to the suspension polymerization process, in the presence of oil-soluble free-radical initiators, dispersion stabilizers and, optionally, other polymerization auxiliaries, the process being characterized in that, as dispersion sta~ilizer, there is employed one or more water-soluble polyvinyl alcohol~s~ (PVAL) which has or have heen manufactured by partially solvolysing polyvinyl acetate (PVAC) in an alcoholic solution in the presence of an acid catalyst.
The abbreviation PVC is intended herein to mean vinyl chloride homopolymers and copolymers of vinyl chloride with up to 40% by weight, based on the VC content of one or more ethylenically-unsaturated monomers that are cop~ly-merizable therewith. Such other monomers are, for example, vinyl esters of aliphatic, linear and/or branched, saturated C2-C18 aliphatic carboxylic acids; such as vinyl ac~tate, vinyl propionate, vinyl butyrate; olefins/ particularly lower l-alkenes, such as ethylene, propylene; esters of unsaturated acids, such as the Cl-C18 alkyl estexs of lower alkenoic and alkendioic acids~ such as acrylic acid esters, methacrylic acid esters, maleic acid esters and fumaric acid esters of Cl-C18 alcohols; and unsaturated ~ ~ 61 ~ ~
acids, part~icularly lower alkenoic acids such as acrylic acid, methacrylic acid, itaconic acid and crotonic acid;
maleic acid and fumaric acid and semiesters thereof. The abbreviation PVC also includes graft polymers of VC and up to 50% by weight, based on the VC, of a polymeric substrate of one or more of the monomers mentioned.
It is known, fo~ example, from European P~atent ~pplication No. EP 0 002 ~61, as well as German Published Application DE~OS No. 26 53 087, to manufacture VC homo-polymers and copolymers in the presence of PVAL, whichgenerally means partially saponified PVAC.
According to both specifications, the suspension polymerization of the monomers is carried out in the presence of a combination of a water-soluble, so called primary, protective colloid with a water-insoluble, so-called secondary, protective colloid. For the manufacture of an acceptable S-PVC, the secondary protective colloid cannot be used in these processes without the primary protective colloid.
According to the above-mentioned European Patent Application, a product having a high porosity, large BET
surface area, narrow particle size distribution and good plasticizer acceptance is obtained and, after processing, it shows only a few "fish eyes".
The process of the above-mentioned German Published ~pplication yields polymers having improved porosity, low residual monomer content, a crumbly structure and a high bulk density.
These properties are only achieved by the combina-tion of a customary water-soluble protective colloid (until now the world market has offered no PVAL
~ 16~9~
manufactured by acid hydrolysis that would be suitable or manufacturing S-PVC) with the water-insoluble secondary protective colloid essential to these applications.
It is mentioned in the European Pa~ent Application that PVAL can be manufactured by solvolysing PVAC in an acidic or basic pH range, but the manufacture of the secondary protective collold, which is described in more detail, is effected exclusively in an alkaline range.
The low degree of hydrolysis of the water-insoluble PVAC is achieved either by early termination of the solvoly-sis, which, however, according to the European Patent Appli-cation, produces avery inhomogeneous poor protective colloid because this reaction takes place very quickly, or by com~
plicated saponification conditions which are described in detail in the above-mentioned specification.
The German Published Application makes reference only to the possibility of manufacturing the secondary protective colloid by acid-catalyzed or alkali-catalyzed saponification which, however, as described above, must be terminated early. Further comments in the above-mentioned German Published Application, for example that the polymer manufactured as described therein, which adheres to the reaction walls and crumbles to a relatively great extent, indicate that the polymer produced contains a large propor-tion of dust-fine particlesu German Patent Application 27 02 771 uses vinyl acetate/vinyl alcohol block copolymers as a secondary pro-tective colloid in the suspension polymerization of VC, in order further to improve the morpholo~y and grain structure of PVC, which are both areas in need of improve-ment. Because they too are complicated to manufacture, however, such block copolymers are unsuitable for use as a protective colloid in the present-day large-scale produc-tion of PVC.
No process is known from the state of the art:that, because of its simplicity, is suitable for the large-scale production of PVC and, at the same time, yields products which are free of dust-fine particles and have improved properties.
An object of the present invention is the production of suspension polyvinyl chloride which is free of dust-fine particle.s and has improved properties.
Another object of the present invention is the development of an improvement in the process fox the produc-tion of suspension-polymerized polyvinyl chlori~e comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to ~0% by weight of monomers copolymerizable with vinyl chloride under suspen-sion polymerization conditions in the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 3 to 8 and a temperature of from 30C to 70C for a time su~ficient to effect polymerization and recovering poly-vinyl chloride, the improvement consisting of employing at least one water-soluble polyvinyl alcohol produced by partially solvolysing polyvinyl acetate in an alcoholic solution in the presence of an acid catalyst, as said at least one dispersion stabilizer, and recovering suspension-polymerized polyvinyl chloride which substantially is free of dust-fine particles and has improved thermostability.
l l 61195 I These and other objects of the invention will become more apparent as the description thereof proceeds~
Surprisingly, it has now been discovered that when ¦ carrying out the process according to the invention in the I presence of a water-soluble PVAL that has been manuactured by partially solvolysing PVAC in alcoholic solution with the addition of an acid catalyst, as a single protective colloid, it is possible to produce a VC polymer without fines and having improved properties. In accordance with the process according to the invention, it is possible to obtain, in a technically simple manner, a PVC which is free of dust-fine particles r which previously could }lOt be obtained without sieving.
More particularly, the present invention relates to the improvement in the process for the production of suspension-polymerized polyvinyl chlorlde comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 40% by weight of monomers copolymeri~able with vinyl chloride under suspen-sion polymerization conditions in the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 1 3 to 8 and a temperature of from 30C to 70C for a time I sufficient to effect polymerization and recovering pol~-I vinyl chloride, the improvement consisting of employing at I least one ~ater-soluble polyvinyl alcohol produced by partially solvolysing polyvinyl acetate in an alcoholic l 1~11~5 solution ;n the presence of an acid catalyst, as ~aid at least one dispersion stabilizer, and recove~ing suspension-polymerized polyvinyl chloxide which subs-~antially is free of dust~fine particles and has improved thermostability ;
as well as the suspension-polymerized polyvinyl chloride which is substantially free of dust-fine particles and has improved thermostability, produced by the aforesaid process.
In PVC processing, a content of dust (particles of dust fineness~ is undesirable for various reasons. ~part from causing inconvenience in the place of work when hand-ling the dust-produclng polymer, the incorporation by mixing o processing auxiliaries, such as plas~icizers, stabilizers, colorants and others, especially in he case of liquid auxiliaries and additives, is rendered more difficult inso-far as differing adsorption properties of fines and of correctly sized particles can lead to an inhomogeneous dis-tribution of these materials. The effect of such conditions is the formation of a coating in the mixer, problems in processing PVC and losses in the quality of the fini~hed article. Fines in PVC are also undesirable, however, in the case of pneumatic material transportation without which large-scale industry cannot operate today, since segrega-tion phenomena after the manner of an air separation can occur. In this manner, inhomogeneities that are difficult to control are caused within a type of product, and this also leads to serious processing problems.
The lack of fines in the PVC manufactured accord~
ing to the invention unexpectedly reduces encrus-tation of the walls of the autocla~e during polymerization, which is almost unavoidable when using known processes. It is thus possible, in a technically simple manner, to dispense with an additional encrustation inhibitor. The lat~er is often the cause of undesirable impurities in the polymer.
Finally, it has been shown that, after polymeriza-tion according to the invention has been completed, the required degassing for removing residual amounts of toxic monomer is rendered considerably simpler by the reduced foaming behavior of the suspension as compared with suspen-sion polymerization using conventional polyvinyl alcohols saponified with an alkali. As a result r it is possible to accelerate the degassing processl which results in a reduc-tion in the time required for working up, less thermal stress on the crude product, and consequently an increase in efficiency.
~ urprisingly, the product manufactured according to the invention also has an improved therrnostability as compared with products that have been manufactured in the conventional manner by suspension polymerization in the presence of PVAL saponified with an alkali.
The water-soluble PVAL used in the process accord-ing to the invention can be added to the aqueous phase ofthe polymerization mixture, preferably in quantities of from 0.02% to 1.0% by weight, based on the monomer content, before the beginning of the polymerization or all or part of the PVAL can be metered in during polymerization. Itist of course, possible additionally to use a secondary protec-tive colloid in quantities of up to a maximum of 1~ by weight, based on the monomer content, in order to achieve special effects. It is, however, preferable to use con-siderably less, for example less than 0.1% by weight, based on the monomer content. Such concomitant use o~ a secondary protective colloid is not, however, necessary for solving 1 J ~
the problem posed initially, of manufacturing a PVC free of dust-fine particles and having improved properties.
The PVAL used according to the invention may be manufactured, for example, as follows:
10 parts by weight of a PVAC of low to moderate viscosity (approximately 3 to approximately 30 mPas, as measured according to H~ppler in a 4~ by weight aqueous solution at 20C) are first dissolved, while being stirred, in 40 parts by weight of methanol. After heating to 60C, 0.5 part by weight of concentrated hydrochloric acid in 1 part by weight of methanol is added while stirring is con-tinued. The extent of the solvolysis now commerlcing is determined by the reaction time. The relationship between the length of the reaction and the degree of hydrolysis may be esta~lished by a few preliminary experiments. To make a qualitative test, the progress of the saponification can be observed using a test tube sample. If, on the addi-tion of plenty of water to the reaction sample, no precipi-tate is formed, then usually a saponification number of less than 400 has been reached, corresponding to a degree of hydrolysis of more than 55 mol~ With further saponifica tion, the test-tube sample becomes increasingly clear on the addition of water. The addition of 50 parts by weight of water to the reaction mixture and neutralization to p~I
~.5 to 7~0 stops the acid hydrolysis at the desired time.
Methanol and methyl acetate are extensively separated off by vacuum distillation, while the corresponding decrease in volume can be compensated for by the addition of water. The result is a clear colorless solution of polyvinyl alcohol in water which, after its degree of saponification and solids content have been determined, can be used in the ~ 1 ~1 19~
resulting Eorm for the suspension polyrneri~ation of vlnyl chloride accordiny to the pre~ent lnvention.
The manufacturiny conditions described above may, of course, be varied within a wide range without influencing the specific pro-tective co~loid properties of the PVAL
manufactured by acid hydrolysis, as long as the specified viscosity range and degree of hydrolysis are observed.
Higher concentrations of PVAC increase the viscosity of the methanolic solution, which must be such that the reaction mixture can still be stirredO The concentration of the PVAC can vary, for example, from approximately 10 to approximately 60 parts by weight per 100 parts by weight of Cl-C3 alkanol. The higher the viscosity of the PVAC, the lower the concentration is set. A variation in temperature is, of course, also possible. Lower temperatures usually lengthen the reaction time and considerably higher temperatures can lead to practical difficulties because of boiling occurring in the reactor. It is also possible to vary the concentration of the acid catalyst, for example, from 0.1 to 5 pa,ts by weight per 100 parts by weight of alcohol. The speed of solvolysis generally increases as the concentration of catalys-t increases, The desired catalyst action is, of course, not limited only to aqueous inorganic acids, particularly aqueous mineral acids such as hydrochloric aciA, hydrobromic acid, hydrofluoric acid, sulfuric acid, phosphoric acid, perchloric acid and mixtures thereof.
As far as it is possible and meaningful, these acids can also be used in anhydrous form Furthermore, it is also possible to use other acidically active inorganic and organic compounds as catalyst, for example, carboxylic acidsj sulfonic ac;ds, mgJ~ g _ -9 5~ ' and phosphonic aci`ds, Suitable acid catalysts may~ ~OX
example, ~e selected with re~erence to the tables in 'IPure and Applied Chemi~stry'l 1 (1960) 187 to 536 and ibid 20 (1969) 133 to 236.~ It is cri`tical that the pH value during solvolysis lies below 6.5~ especially below 5~ i`n order to ensure that the solvolysis takes place sufficiently qu~ckly.
After terminatin~ the solvolysis~ di~still;~n~ of~ the vola-tile oxganic compounds present in the reaction mixtu~e/ and taking up in water, the PVAL can be used in the proce~s accQrdi`ng to the invention. A preferred PVAL is one havIng a Viscosi`ty of from approximately 2 to 30 mPasr especially from 2 to 10 mPas~ as measured according to H~ppler in a 4~ by we~ght aqueous solution at 20C, and preferably having a degree of hydrolysis of ~rom ~pproximately 55 to 85 mol%, correspondi`n~ to a saponificatio~ number of fro~ approxi-mately 40a to approximately 1~5~
The process according to the invention is carried out in a manner known per se in the presence of oil-soluble (monomer-soluble) free-radical initiators or mixturés thereof~ such as organic peroxides or azo compounds, for example acyl peroxides, percarbonates, acyl cyclohexane-sulfonyl peroxides, peresters, azocarboxylic acid nitriles and the like, and, optionally, known polymerization auxil-iaries, it being possible for the concentrations of these compounds to lie within the generally customary ranges.
Suitable polymerization auxiliaries that may optionally be used are, for example, emulsifiers, buffer substances, molecular-weight regulators and encrustation inhibitors.
These auxiliaries are not essential for achieving the ad~antages according to the invention: their concomitant or non-concomitant use and the time, ~pe and quantity of ~ 3 ~
their addition are not decisive criteria and thus also do not represent limitations of the invention, as their opti-mum values can be determined by the expert in a few experiments. The polymerization reaction is preferably conducted at a pH of from 3 to 8 and at a temperature of from 30C to 70C, as is customary.
The following examples and comparison tests illus-trate the present invention in more detail without being limitative.
EXAMPLES
The products were analyzed by carrying out tests for sieve analysis, dust, pressing stability and furnace stability as described below. (ppm = parts by weight/106 parts by weight~
Sieve analysis:
. . . _ . . _ Alpine air jet sieve. (by Alpine AG, Augsburg, West Germany~
Dust test:
80 gm of a dried P~C sample were trickled through ~ a vertically mounted PVC tube of 1 ~ length and 25 mm diameter. The portion adhering to the wall of the tube as a result of electrostatic charge was weighed and its per-centage of the original weight determined.
Pressing stabilit~:
100 parts by weight o~ PVC were mixed with 50 parts by weight of di-2-ethylhexyl phthalate, 0.5 parts by weight of tribasic lead sulfate and 0.2 parts by weight of montan wax ~wax E), and processed on a roll mill for 2 minu-tes at 170C to form a rolled sheet. This rolled sheet was then pressed for 10 minutes at 180C or 190C to form a 1 mm thick pressed plate. The discoloration occurriny as a l q ~ 195 result of too little stabilization was measured colori-metrically according to German Industrial Standard DIN 6174.
In comparison with a measuring standard of unlimited trans-mission (measured value 100), decreasing numerical values indicate increasing discoloration.
Furnace stability:
In two recipes, A and B, as given in the Table, 1 mm thick rolled P~TC shee~s were produced by rolling for 10 minutes at 170C and were then subjected to a Matthis Thermotest at 190C. In this test, a PVC strip cut from the rolled sheet was drawn through a heating furnace at a constant speed. The distance in mm from the starting point to the beginning of a dark-brown coloration is a measure of the heat stability.
Comparison Test A
A 2-m agitating autoclave was charged ~ith the following components in the order specified 930 parts by weight of de-ionized water
2.3 parts by weight of a polyvinyl alcohol dissolved in 20 parts by weight of water 0.15 parts by weight of sodium bicarbonate, and 0.31 parts by weight of dicetyl perio~ydicarbonate.
The polyvinyl alcohol, corresponding to the state of the art, had a degree of saponification of 76 mol~ and a viscosity of 5 mPas as measured according to Hoppler in a 4% by weight aqueous solution at 20C~ It was prepared by alkaline saponification of a P~AC with a degree of polymeri-zation of 500, as determined by osmotic measurement.
After sealing the autoclave, evacuation was carried out twice, to 0.2 bar each time, re~axation of the vacuum 1 3 61~9~
being carried out in between with inert gas. After the second evacuation, 570 parts by weight of vinyl chloride were added. The mixture thus prepared was then heated to 59C while stirring (impeller at 130 min )O After an operating time of 6-3/4 hours under autogenous ~C pressure, the pressure fell by 1.5 bar. At this point, the polymeri-zation was broken of by relaxation of the pressure. After pressure equalization, the residual VC was removed by fur-ther heating to 70 to 75C, finally applying a vacuum of 0.4 bar for a period of 2 hours. This operation had to be carried out with appropriate care by throttling the gas outflow in order to avoid undesirable foaming over. After 2 hours, the pressure was returned to atmospheric and the resulting suspension PVC was worked up in the conventional manner by filtering or centrifugation, washing and drying.
The centrifuged moist product had, after the two-hour degassing, a residual VC content of 200 ppm, based on its weight and determined by gas chromatography. The values for the analysis of the product are given in the Table.
The autoclave had to be cleaned with a high-pressure-water cleaning apparatus after -the completion of the polymeriza-tion.
EXAMPL~ 1 The procedure given in Comparison Test A was repeated with the modification that the P~AL used as the dispersion stabilizer had been obtained by acid hydrolysis (concentrated HCl as catalyst) of the polyvinyl acetate used as starting material in Comparison Test A. As above, the PVAC had an average degree of polymerization, measured osmotically, of 500. The PVAL manufactured from this by l ~ 61 ~95 acid hydrolysis, in accordance with the process giveniin the description; had a degree of hydrolysis of 75 mol% and a viscosity o 3.2 mPas (as measured according to Hoppler in a 4% by weight aqueous solution at 20C).
The suspension PVC prepared in this manner differed from that of the Comparison Test in its content of fines and in the thermal properties. The analysis of the product is also given in the ~able.
After carrying out the degassing procedure specified in Comparison Test A, the centrifuged moist prcduct had a residual VC content;of 100 ppm. On applying a vacuum, less foaming was observed than in the comparison test so that the gas outflow clearly needed to be throttled to a lesser extent. The autoclave walls were practically free of impurities or deposits so that simply rinsing with water was sufficient to clean the autoclave.
The autoclave was not cleaned further and Example 1 was repeated using a mixture of equal parts of two poly-vinyl alcohols having differing degrees of hydrolysis in-stead of the single PVAL having a degree of hydrolysis of 75 mol%. Both PVALs were again produced by acid hydrolysis from the polyvinyl acetate specified in Comparison Test A
and Example 1. They had degrees of hydrolysis of 68 mol%
and 75 mol% respectively so that equal proportions by weight resulted in an average degree of hydrolysis of 72 mol%. The correspondingly produced S-PVC difered only insignificantly from the polymer obtained according to Example 1. Reduced foaming behavior also occurred in the present case when degassing the polymerization preparation.
The autoclave did not need to be cleaned for further ~ 1 ~1 .1,9~
polymerization preparations.
The properties of the product are also shown in the Table.
1 3 ~
_. __ _ U~ .~ oo ~ ~
~ ~ _ _ O ~ ~ ~ ~ ~ æ
U~~ U~
~9 ~ In I
U~ ~ ~ __ _ .~ .
~ U~ ~ ~
_ U~ U~ ~ _ O
L~ ~ o~ ~ O O m I
~ o, ~1 ~3 ~1 O O
r-l , '.C3 Ir~ O O __~
~ ~ ` O , O CO ~D
~: ~ ~ _ _ æ ~
. ~ ~D ~ ~D
.o ,i In ui : .~1 a o ~ .~ t t . o ~ ~r , ~
tq __ _ _ __ ~ .,, t~1 Ul ~ o ~D ~ tn ~ I O O O N _ , !~
u~ o o o o ~d ` ~ ~ r~ o _ o o _ ~) I~ _ ~
~ tqd~ ~
~ a ~ co Ln .~ ~o p;
.~ 8 ~ ~ ~ ~ r~ w ~ ~
~ ------ .~ ~
rlri ~ ~ ~ ~ ~ tq rl d. ~ O O O O .,~
~I h a) __ _ __ _ ~ ~
. ~ ~ ~ _ ~_1 ~1 _ ~ ~t~
The preceding Table clearly demonstrates the improved properties of the PVC produced according to the invention employing PV~C solvolysed in an alcohol in the presence of an acid catalyst.
The preceding specific embodiments are illustra-tive of the practice of the invention. It is to be under-stood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the inYention or the scope of the appended claims.
The polyvinyl alcohol, corresponding to the state of the art, had a degree of saponification of 76 mol~ and a viscosity of 5 mPas as measured according to Hoppler in a 4% by weight aqueous solution at 20C~ It was prepared by alkaline saponification of a P~AC with a degree of polymeri-zation of 500, as determined by osmotic measurement.
After sealing the autoclave, evacuation was carried out twice, to 0.2 bar each time, re~axation of the vacuum 1 3 61~9~
being carried out in between with inert gas. After the second evacuation, 570 parts by weight of vinyl chloride were added. The mixture thus prepared was then heated to 59C while stirring (impeller at 130 min )O After an operating time of 6-3/4 hours under autogenous ~C pressure, the pressure fell by 1.5 bar. At this point, the polymeri-zation was broken of by relaxation of the pressure. After pressure equalization, the residual VC was removed by fur-ther heating to 70 to 75C, finally applying a vacuum of 0.4 bar for a period of 2 hours. This operation had to be carried out with appropriate care by throttling the gas outflow in order to avoid undesirable foaming over. After 2 hours, the pressure was returned to atmospheric and the resulting suspension PVC was worked up in the conventional manner by filtering or centrifugation, washing and drying.
The centrifuged moist product had, after the two-hour degassing, a residual VC content of 200 ppm, based on its weight and determined by gas chromatography. The values for the analysis of the product are given in the Table.
The autoclave had to be cleaned with a high-pressure-water cleaning apparatus after -the completion of the polymeriza-tion.
EXAMPL~ 1 The procedure given in Comparison Test A was repeated with the modification that the P~AL used as the dispersion stabilizer had been obtained by acid hydrolysis (concentrated HCl as catalyst) of the polyvinyl acetate used as starting material in Comparison Test A. As above, the PVAC had an average degree of polymerization, measured osmotically, of 500. The PVAL manufactured from this by l ~ 61 ~95 acid hydrolysis, in accordance with the process giveniin the description; had a degree of hydrolysis of 75 mol% and a viscosity o 3.2 mPas (as measured according to Hoppler in a 4% by weight aqueous solution at 20C).
The suspension PVC prepared in this manner differed from that of the Comparison Test in its content of fines and in the thermal properties. The analysis of the product is also given in the ~able.
After carrying out the degassing procedure specified in Comparison Test A, the centrifuged moist prcduct had a residual VC content;of 100 ppm. On applying a vacuum, less foaming was observed than in the comparison test so that the gas outflow clearly needed to be throttled to a lesser extent. The autoclave walls were practically free of impurities or deposits so that simply rinsing with water was sufficient to clean the autoclave.
The autoclave was not cleaned further and Example 1 was repeated using a mixture of equal parts of two poly-vinyl alcohols having differing degrees of hydrolysis in-stead of the single PVAL having a degree of hydrolysis of 75 mol%. Both PVALs were again produced by acid hydrolysis from the polyvinyl acetate specified in Comparison Test A
and Example 1. They had degrees of hydrolysis of 68 mol%
and 75 mol% respectively so that equal proportions by weight resulted in an average degree of hydrolysis of 72 mol%. The correspondingly produced S-PVC difered only insignificantly from the polymer obtained according to Example 1. Reduced foaming behavior also occurred in the present case when degassing the polymerization preparation.
The autoclave did not need to be cleaned for further ~ 1 ~1 .1,9~
polymerization preparations.
The properties of the product are also shown in the Table.
1 3 ~
_. __ _ U~ .~ oo ~ ~
~ ~ _ _ O ~ ~ ~ ~ ~ æ
U~~ U~
~9 ~ In I
U~ ~ ~ __ _ .~ .
~ U~ ~ ~
_ U~ U~ ~ _ O
L~ ~ o~ ~ O O m I
~ o, ~1 ~3 ~1 O O
r-l , '.C3 Ir~ O O __~
~ ~ ` O , O CO ~D
~: ~ ~ _ _ æ ~
. ~ ~D ~ ~D
.o ,i In ui : .~1 a o ~ .~ t t . o ~ ~r , ~
tq __ _ _ __ ~ .,, t~1 Ul ~ o ~D ~ tn ~ I O O O N _ , !~
u~ o o o o ~d ` ~ ~ r~ o _ o o _ ~) I~ _ ~
~ tqd~ ~
~ a ~ co Ln .~ ~o p;
.~ 8 ~ ~ ~ ~ r~ w ~ ~
~ ------ .~ ~
rlri ~ ~ ~ ~ ~ tq rl d. ~ O O O O .,~
~I h a) __ _ __ _ ~ ~
. ~ ~ ~ _ ~_1 ~1 _ ~ ~t~
The preceding Table clearly demonstrates the improved properties of the PVC produced according to the invention employing PV~C solvolysed in an alcohol in the presence of an acid catalyst.
The preceding specific embodiments are illustra-tive of the practice of the invention. It is to be under-stood, however, that other expedients known to those skilled in the art or disclosed herein, may be employed without departing from the spirit of the inYention or the scope of the appended claims.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In the process for the production of sus-pension-polymerized polyvinyl chloride comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 40% by weight of monomers copoly-merizable with vinyl chloride under suspension polymeriza-tion conditions In the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 3 to 8 and a temperature of from 30°C to 70°C for a time sufficient to effect polymerization and recovering polyvinyl chloride, the improvement consisting of employing at least one water-soluble polyvinyl alcohol produced by partially solvolysing polyvinyl acetate in an alcoholic solution in the presence of an aqueous mineral acid catalyst, said polyvinyl alcohol so produced having a degree of hydrolysis of from 55 to 85 mol %, as said at least one dispersion stabilizer, and recovering suspension polymerized polyvinyl chloride which substantially is free of dust-fine particles and has im-proved thermostability.
2. The process of claim 1 wherein said polyvinyl alcohol has a Hoppler viscosity of from 2 to 30 mPas measured in a 4% by weight aqueous solution at 20°C.
3. The process of claim 2 wherein said poly-vinyl alcohol has a Hoppler viscosity of from 2 to 10 mPas measured in a 4% by weight aqueous solution at 20°C.
4. The process of claim 1 wherein said at least one water-soluble polyvinyl. alcohol is employed in an amount of from 0.02% to 1.0% by weight, based on the monomer content.
5. The process of claim 1 wherein said poly-vinyl acetate is partially solvolysed in a Cl-C3 alkanol in the presence of an acid catalyst at a pH of below 6.5
6. The process of claim 5 wherein said pH is maintained below 5.
7. The suspension-polymerized polyvinyl chloride which is substantially free of dust-fine particles and has improved thermostability produced by the process of claim 1. .
8. In the process for the production of sus-pension-polymerized polyvinyl chloride comprising the steps of heating an aqueous suspension of monomers selected from the group consisting of vinyl chloride and mixtures of vinyl chloride with up to 40% by weight of monomers copoly-merizable with vinyl chloride under suspension polymeriza-tion conditions in the presence of at least one monomer-soluble, free-radical polymerization catalyst and at least one dispersion stabilizer at a pH of from 3 to 8 and a tem-perature of from 30C to 70°C for a time sufficient to effect polymerization and recovering polyvinyl chloride, the improvement consisting of employing from 0.02% to 1.0%
by weight, based on the monomer content of at least one water-soluble polyvinyl alcohol produced by partially sol-volysing polyvinyl alcohol in a Cl-C3 alkanol solution in the presence of an aqueous mineral acid catalyst at a pH
of below 6.5, said polyvinyl alcohol so produced having a degree of hydrolysis of from 55 to 85 mol % and a Hoppler viscosity of from 2 to 30 mPas measured in a 4% by weight aqueous solution at 20°C, as said at least one dispersion stabilizer, and recovering suspension-polymerized polyvinyl chloride which substantially is free of dust-fine particles and has improved thermostability,
by weight, based on the monomer content of at least one water-soluble polyvinyl alcohol produced by partially sol-volysing polyvinyl alcohol in a Cl-C3 alkanol solution in the presence of an aqueous mineral acid catalyst at a pH
of below 6.5, said polyvinyl alcohol so produced having a degree of hydrolysis of from 55 to 85 mol % and a Hoppler viscosity of from 2 to 30 mPas measured in a 4% by weight aqueous solution at 20°C, as said at least one dispersion stabilizer, and recovering suspension-polymerized polyvinyl chloride which substantially is free of dust-fine particles and has improved thermostability,
9. The suspension-polymerized polyvinyl chloride which is substantially free of dust-fine particles and has improved thermostability produced by the process of claim 8.
mab/
mab/
10. The process of claim 8 wherein said aqueous mineral acid catalyst is a mineral acid selected from the group consisting of hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, phosphonic acid, per-chloric acid and mixtures thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3001517.9 | 1980-01-17 | ||
| DE19803001517 DE3001517A1 (en) | 1980-01-17 | 1980-01-17 | METHOD FOR PRODUCING DUST-FREE POLYVINYL CHLORIDE WITH IMPROVED PROPERTIES |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1161195A true CA1161195A (en) | 1984-01-24 |
Family
ID=6092253
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000364216A Expired CA1161195A (en) | 1980-01-17 | 1980-11-07 | Process for the manufacture of suspension polyvinyl chloride free of dust-fine particles and having improved properties |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0032724B1 (en) |
| JP (1) | JPS5811443B2 (en) |
| CA (1) | CA1161195A (en) |
| DE (2) | DE3001517A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6870009B2 (en) | 2001-08-16 | 2005-03-22 | Wacker Polmer Systems Gmbh & Co. Kg | Polyvinyl acetals with improved adhesion |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8301463A (en) * | 1983-04-26 | 1984-11-16 | Stamicarbon | VINYL CHLORIDE POLYMERS. |
| PT86940B (en) * | 1987-03-12 | 1992-05-29 | Shinetsu Chemical Co | PROCESS FOR THE PREPARATION OF AN IMPROVED COMPOSITION OF POLYVINYL CHLORIDE RESIN |
| EP0978538B1 (en) * | 1997-04-01 | 2004-06-30 | Nippon Gohsei Kagaku Kogyo Kabushiki Kaisha | Highly stable aqueous solution of partially saponified vinyl ester resin |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5217870B2 (en) * | 1973-01-31 | 1977-05-18 | ||
| IT1055887B (en) * | 1976-02-17 | 1982-01-11 | Sigma Italiana Prod Chimici | PROCESS PERFECTED FOR THE PRODUCTION OF POLIVINLI CHLORIDE |
| NL7714034A (en) * | 1977-12-19 | 1979-06-21 | Stamicarbon | VINYL CHLORIDE POLYMERS. |
-
1980
- 1980-01-17 DE DE19803001517 patent/DE3001517A1/en not_active Withdrawn
- 1980-09-24 JP JP55131748A patent/JPS5811443B2/en not_active Expired
- 1980-11-07 CA CA000364216A patent/CA1161195A/en not_active Expired
-
1981
- 1981-01-15 EP EP81100267A patent/EP0032724B1/en not_active Expired
- 1981-01-15 DE DE8181100267T patent/DE3160663D1/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6870009B2 (en) | 2001-08-16 | 2005-03-22 | Wacker Polmer Systems Gmbh & Co. Kg | Polyvinyl acetals with improved adhesion |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3160663D1 (en) | 1983-09-01 |
| DE3001517A1 (en) | 1981-07-30 |
| EP0032724A2 (en) | 1981-07-29 |
| JPS56104912A (en) | 1981-08-21 |
| EP0032724A3 (en) | 1981-12-30 |
| JPS5811443B2 (en) | 1983-03-03 |
| EP0032724B1 (en) | 1983-07-27 |
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