CA1082847A - Method of polymerizing vinyl chloride in seeded microsuspension - Google Patents
Method of polymerizing vinyl chloride in seeded microsuspensionInfo
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- CA1082847A CA1082847A CA251,402A CA251402A CA1082847A CA 1082847 A CA1082847 A CA 1082847A CA 251402 A CA251402 A CA 251402A CA 1082847 A CA1082847 A CA 1082847A
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- weight
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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
- C08F259/00—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00
- C08F259/02—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00 on to polymers containing chlorine
- C08F259/04—Macromolecular compounds obtained by polymerising monomers on to polymers of halogen containing monomers as defined in group C08F14/00 on to polymers containing chlorine on to polymers of vinyl chloride
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- Chemical & Material Sciences (AREA)
- 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)
- Graft Or Block Polymers (AREA)
- Polymerisation Methods In General (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A method for preparing polymers of vinyl chloride in which poly-merization of the corresponding monomer or monomers is carried out in micro-suspension in the presence of a seeding product in the form of a dispersion of particles of a vinyl polymer previously prepared by polymerization in micro-suspension, the particles of which contain at least one organic soluble initi-ator, without any complementary addition of initiator and in the presence of one or more other seeding product in the form of dispersion of vinyl polymer, the sizes of which differ from one another and from the particles of the first seeding product. The polymers obtained are in the form of powders particu-larly suitable for preparing plastisols having Newtonian or pseudoplastic behaviour with a very low plasticizer content and a low viscosity which enables coatings to be applied at very high speed.
A method for preparing polymers of vinyl chloride in which poly-merization of the corresponding monomer or monomers is carried out in micro-suspension in the presence of a seeding product in the form of a dispersion of particles of a vinyl polymer previously prepared by polymerization in micro-suspension, the particles of which contain at least one organic soluble initi-ator, without any complementary addition of initiator and in the presence of one or more other seeding product in the form of dispersion of vinyl polymer, the sizes of which differ from one another and from the particles of the first seeding product. The polymers obtained are in the form of powders particu-larly suitable for preparing plastisols having Newtonian or pseudoplastic behaviour with a very low plasticizer content and a low viscosity which enables coatings to be applied at very high speed.
Description
4q The invention relates to a method of preparing polyvinyl chloride and copolymers of vinyl chloride by polymerization in seeded microsuspension.
It also relates to the resultant polyvinyl chloride and copolymers.
Polymerization in microsuspension, or fine suspension, is under-stood as being polymerization, in the presence of initiators soluble in or-ganic material, of at least one monomer dispersed by powerful mechanical means in an aqueous medium containing an emulsifier as stabili~er, in order to ob-tain a dispersion of particles of an average diameter less than 5 microns.
It is known, from Canadian Patent No. 875,050 issued on July 6, 1971 to Produits Chimiques Pechiney-Saint~Gobain, to prepare polymers of vinyl chloride in microsuspension, in the presence of a seeding product con-taining all the ;n;tiator necessary for polymerization. However, when poly-merization is carried out so as to obtain a latex with a polymer concentration of over 45%~ the high viscosity of the medium necessitates slower agitation, owing to the mechanical instability of the latex formed. This slow agitation leads to a decrease in the coefficients of exchange, which means that the polymerizing time has to become longer.
Moreover when the polymers obtained are used to prepare plastisols, the plastisols are difficult to use because of their dilatance, i.e. the increase of their viscosity with the speed gradient, and because the minimNm proportion of plasticizer that can be used is 50 parts per 100 of polymer.
It is also known that, in the case of polymers of vinyl chloride prepared by polymerization in emulsion, the use of a plastisol is improved if the polymer comprises elementary particles forming at least two populations which have particles of different sizes. This plurality of populations can be 1082~7 obtained by mixing scveral latices comprising particles of different sizes, but the mixture cannot be made at a high concentration. Another solution consists of simultancously preparing the various populations of particles by l~o~ymcrization in cmulsion of at least one monomer in the presence of several sccdirl~ ~roducts prc~arod by polymerization in cmulsion. ~lowever, this oper-ation is very tricky, for the quantity of emulsifier used has to be stipulated and limited and its introduction require~ special care, that is to say, a specific introductîon all the time, in order to avoid nucleation of new par-ticles which would limit the polymer concentration of the latex obtained.
Moreover it is difficult to make seeding products with particles of very small sizes which are measured and homogeneous, since the slightest variation in particle size results in variation in the ratios of the dimensions and in the proportions of the various populations obtained after polymerization.
The method of the invention avoids these drawbacks and enables latices to be prepared by polymerization in microsuspension, without any limitations, precautions or difficulties; the latices having a polymer con-centration well over 45% by weight, a low viscosity and a reproducible par-ticle size. Furthermore, the polymers thus obtained are easy to convert and more particularly adapted to give plastisols which may contain very little plasticizer but which are nevertheless easy to use.
According to the invention there is provided a method of pre-paring a polymer of vinyl chloride which is polyvinyl chloride or a copolymer containing at least 50% by weight of vinyl chloride and at least one copoly-merizable monomer, whioh method comprises polymerizing the corresponding monomer or monomers in microsuspension, in the presence of a first seeding product in the form of a dispersion of particles of a vinyl polymer previously prepared by polymerization in microsuspension, the particles of which contain at least one initiator soluble in organic material, without any complimentary addition of initiator, characterized in that polymerization is carried out in the presence of one or more other seeding products in the form of dispersions of particles of vinyl polymer, the sizes of which differ from one another and from the particle size of the first seeding product.
C
. ~ - 2 -1082~7 Thus, the method of preparing polymers of vinyl chloride com-prises polymeri~ing the corresponding monomer or monomers in microsuspension, in the presence of a seeding product in the form of a dispersion of 2a -10~ 47 particleq o.f a ~7n,y 1 polymer previousli ~rcparcd by polymeliza-tion in microsuspension, the p~rticles of which contain at least one initi~tor soluble in organic mate~rial, without any complementary addition of initiator. The method is chaxacter-ized in that polymerization is carried out in the presence ofone or more other seedin~ products in the form of dispersi.ons of particles o vinyl polymer, in which the sizes of the par-ticles differ from one another and differ from that of the first seeding product; the particles may contain at least one initiator.
Polymers of vinyl chloride refer to polyvinyl chlor-ide and to copolymers containing at least 5~/0 by weight of vinyl chloride and at least one monomer which is copolymeriz-able with vinyl chloride. The copolymerizable monomers are those generally employed in conventional methods of copolymer-izing vinyl chloride. Some examples are vinyl esters of mono-and poly-carboxylic acids, such as vinyl acetate, propionate and benzoate; unsaturated mono- and poly-carboxylic acids such as acrylic, methacrylic, maleic, fumaric and itaconic acid as well as their aliphatic, cycloaliphatic and aromatic esters, their amides and their nitriles; vinyl and vinylidene halides;
alkyl vinyl ethers and olefins.
The vinyl polymers, which constitute seeding produ~ts, are represented by the polymers of vinyl chloride defined above
It also relates to the resultant polyvinyl chloride and copolymers.
Polymerization in microsuspension, or fine suspension, is under-stood as being polymerization, in the presence of initiators soluble in or-ganic material, of at least one monomer dispersed by powerful mechanical means in an aqueous medium containing an emulsifier as stabili~er, in order to ob-tain a dispersion of particles of an average diameter less than 5 microns.
It is known, from Canadian Patent No. 875,050 issued on July 6, 1971 to Produits Chimiques Pechiney-Saint~Gobain, to prepare polymers of vinyl chloride in microsuspension, in the presence of a seeding product con-taining all the ;n;tiator necessary for polymerization. However, when poly-merization is carried out so as to obtain a latex with a polymer concentration of over 45%~ the high viscosity of the medium necessitates slower agitation, owing to the mechanical instability of the latex formed. This slow agitation leads to a decrease in the coefficients of exchange, which means that the polymerizing time has to become longer.
Moreover when the polymers obtained are used to prepare plastisols, the plastisols are difficult to use because of their dilatance, i.e. the increase of their viscosity with the speed gradient, and because the minimNm proportion of plasticizer that can be used is 50 parts per 100 of polymer.
It is also known that, in the case of polymers of vinyl chloride prepared by polymerization in emulsion, the use of a plastisol is improved if the polymer comprises elementary particles forming at least two populations which have particles of different sizes. This plurality of populations can be 1082~7 obtained by mixing scveral latices comprising particles of different sizes, but the mixture cannot be made at a high concentration. Another solution consists of simultancously preparing the various populations of particles by l~o~ymcrization in cmulsion of at least one monomer in the presence of several sccdirl~ ~roducts prc~arod by polymerization in cmulsion. ~lowever, this oper-ation is very tricky, for the quantity of emulsifier used has to be stipulated and limited and its introduction require~ special care, that is to say, a specific introductîon all the time, in order to avoid nucleation of new par-ticles which would limit the polymer concentration of the latex obtained.
Moreover it is difficult to make seeding products with particles of very small sizes which are measured and homogeneous, since the slightest variation in particle size results in variation in the ratios of the dimensions and in the proportions of the various populations obtained after polymerization.
The method of the invention avoids these drawbacks and enables latices to be prepared by polymerization in microsuspension, without any limitations, precautions or difficulties; the latices having a polymer con-centration well over 45% by weight, a low viscosity and a reproducible par-ticle size. Furthermore, the polymers thus obtained are easy to convert and more particularly adapted to give plastisols which may contain very little plasticizer but which are nevertheless easy to use.
According to the invention there is provided a method of pre-paring a polymer of vinyl chloride which is polyvinyl chloride or a copolymer containing at least 50% by weight of vinyl chloride and at least one copoly-merizable monomer, whioh method comprises polymerizing the corresponding monomer or monomers in microsuspension, in the presence of a first seeding product in the form of a dispersion of particles of a vinyl polymer previously prepared by polymerization in microsuspension, the particles of which contain at least one initiator soluble in organic material, without any complimentary addition of initiator, characterized in that polymerization is carried out in the presence of one or more other seeding products in the form of dispersions of particles of vinyl polymer, the sizes of which differ from one another and from the particle size of the first seeding product.
C
. ~ - 2 -1082~7 Thus, the method of preparing polymers of vinyl chloride com-prises polymeri~ing the corresponding monomer or monomers in microsuspension, in the presence of a seeding product in the form of a dispersion of 2a -10~ 47 particleq o.f a ~7n,y 1 polymer previousli ~rcparcd by polymeliza-tion in microsuspension, the p~rticles of which contain at least one initi~tor soluble in organic mate~rial, without any complementary addition of initiator. The method is chaxacter-ized in that polymerization is carried out in the presence ofone or more other seedin~ products in the form of dispersi.ons of particles o vinyl polymer, in which the sizes of the par-ticles differ from one another and differ from that of the first seeding product; the particles may contain at least one initiator.
Polymers of vinyl chloride refer to polyvinyl chlor-ide and to copolymers containing at least 5~/0 by weight of vinyl chloride and at least one monomer which is copolymeriz-able with vinyl chloride. The copolymerizable monomers are those generally employed in conventional methods of copolymer-izing vinyl chloride. Some examples are vinyl esters of mono-and poly-carboxylic acids, such as vinyl acetate, propionate and benzoate; unsaturated mono- and poly-carboxylic acids such as acrylic, methacrylic, maleic, fumaric and itaconic acid as well as their aliphatic, cycloaliphatic and aromatic esters, their amides and their nitriles; vinyl and vinylidene halides;
alkyl vinyl ethers and olefins.
The vinyl polymers, which constitute seeding produ~ts, are represented by the polymers of vinyl chloride defined above
2~ and by homopolymers of the above-mentioned copolymerizabla monomers, or copolymers formed by the said monomers.
The polymers of the various seeding products in one and the same operation may be identical or different.
The use of a vinyl polymer other than vinyl chloride as a seedin~ product may make it possible to improve certain ~08Z84!7 mech~nic~l prOpQrties or the suitability of the resul'ant poly-mers for processing such as extrusion or calendering.
~rhe ~irst seeding product nccessary for polymeriæa-tion is prepared by conventional methods of polymerization in microsuspension. It is in the form of a dispersion of parti-cles of poly~er with an average diameter from 0.05 to 1.5jum and preferably from 0.2 to 1 ~m.
A method of preparing the first seeding product com-prises using water, a vinyl monomer or a mixture of vinyl mono-mers, an initiator soluble in organic material and an anionic emulsifier possibly associated with a non~ionic emulsifier. ~
The monomer or monomers are finely dispsrsed in the water with the aid of a powerful mechanical means such as a colloid mill, a high speed pump, a vibrating agitator or an ultxasonic ma-chine. The micxosuspension obtained is then heated under auto-genous pressure and with moderate agitation to a temperature generally from 30 to 65C. When the pressure has dropped, the reaction is stopped and the unconverted monomer or mono-mers are degassed.
The initiators which are soluble in organic material and which are to be used in preparing the seeding product are represented by organic peroxides such as diacyl paroxides;
among these mention should be made of lauroyl, decanoyl and caproyl peroxides, tertio'~utyl diethylperacetate, diethyl-hexyl percarbonate and diacetyl peroxide.
The choice of the initiator soluble in organic mater-ial depends on the speed at which it decomposes at the temper-ature used for the reaction. The initiator must in fact be reactive enough for normal ~uantities, of the crder of 0~1 to 3% by weight relative to the monom r or mixture o~ monomers, ~O~Z~7 to enable t}.e se~di~g produ~t to be prepared within periods of 4 to 20 h~l~s. However, the decomposing speed of the initia-tor should not be too high, so that the ~lantity oE initiator decomposed in preparing thc seeding product is not more than half the quantity of initiator used. It is therefore import-ant to select an initiator with a half-life time such that the proportion of initiator destroved in preparing the seeding product is from 5 to 50O/o by weight of all the initiator used.
In cases where several of euch initiators are used, it is advantageous to choose ones of different reactivity; the most reactive initiators are active chiefly during the prepar-ation of the seeding product, whereas the less reactive initiat-ors are active meinly during the seeded polymerization of the vinyl chloride or of the mixture of vinyl chloride and copoly merizable monomer.
The other seediny product or products are in the form of dispersions of particles of polymer, which may or may not contain an initiator; their average diameters, which differ from one another and from that of the first seeding product, are from 0.02 to 1.5 ~m and preferably from 0.02 to 0.8 ~m.
For example, in cases where there are only two seeding products, the average diameter of the particles of the second seeding product is from 0.05 to 1.5,um and preferably from 0~5 to 0.8 ~m; and in cases where there are three seeding products, the average diameter of the particles ofthe second seedin~ product is from 0.05 to 1.5 ~Im and preferably from 0.05 to 0.8 ~m, and the average diameter of the particles of the third seeding product is from 0.02 to 0.8 ~m and preferably from 0.02 to 0.5 ~m.
These dispersions of particles may be obtained by 108284r7 conventio;lal rl~tllods of polymeri~ation in microsusp~nsion or in cmul~ion.
The preparation o~ the seeding product or products, other than the first one, when carried out by polymerization in microsuspension, takes place as described above, but there is a greater degree of homogenization if the particles to be obtained are very small. In the method of the invention it is generally more advantageous to use one or more seeding products, other than the first, whicn do not contain any initiator. They are then polymerized with a quantity of initiator such that at least 8~/o by weight of the initiator is destroyed during the reaction.
Preparation of the seeding product or products, other than the first one, when carried out by polymerization in emul-sion, comprises using water, a vinyl monomer, either alon~ orassociated with a copolymerizable monomer, a water-soluble initiator and an anionic emulsifier, possibly associated with a non-ionic emulsifier.
The size of the particles is regulated by the usual methods suitable for polymerization in emulsion, e.g. by care-fully choosing the nature and quantity of emulsifier used, by using seeds and by adjusting the agitating speed.
The reaction mixture is heated under autogenous pressure and with moderate agitation to a temperature from 30 to 65C. When the pressure has dropped, the reaction is stop-ped and the unconverted monomer or monomers are degassed.
The water-soluble initiators required for preparing these seeding products are generally represented by hydrogen peroxide, persulphates of alkali metals or of ammonium, possibly associated with water-soluble reducing agents, such ~082~4!7 as ~ulphites or bi~ulphites of alkali metals. The quantities used vary greatly, dep~nding on the initiating system chosen ancl a~e just sufficient to insure polymerization within periods of 4 to lO hours.
In polymerization according to the invention, the total quantity of the various seeding products used must be such that the quantity of polymers contained therein is 1 to 5~/O by weight of the sum of vinyl chloride (with or without co-monomer to be polymerized) plus seeding polymers. A quantity of over 50% of seeding polymers can be used but is of little interest, for it is then very large relative to the vinyl chloride or mixture of vinyl chloride and copolymerizable monomer, and the advantages of the invention are thus mini-mized. A quantity of less than 1% of seeding polymers i5 also of very little intere9t, for the quantity of reactive initiator contained in the first seeding polymer or in two or more seed-ing polymers is then very small and does not, in practice, enable the vinyl chloride or mixture of vinyl chloride and copolymerizable monomer to be polymerized. It is in fact the excess initiator in the first seeding polymer or in two or mo~e seeding polymers that very effectively initiates polymerization of the vinyl chloride or mixture of vinyl chloride and copoly-merizable monomer, by setting up a regular reaction speed, as was shown in French Patent ~o. l,485,547.
The proportion of the first seeding polymer to the other seeding polymer or pol~mers, which depends on the com-position of the polymer to be obtained, is from 95/5 to 5/95.
Thus there are several possible ways of carrying out sesded polymerization. Sone examples of these are:
- Using a first seeding produc~, prepared by . ~-108Z8~Y7 pol~m~riz~tion in microsuspension, in which the polymer parti-clcs contain an initiator soluble in organic material; either witll a second seeding ~roduct, prepared by polymerization in ~mu:Lsion or in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, do not contain any initiator; or with a second seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, contain an initiator soluble in organic material - Using a first seeding product, prepared by poly-merization in microsuspension, in which the polymer paxticles contain an initiator soluble in organic material, with a second seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, do not contain any initiator: either with a third seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are finer than those of the second seeding product, do not co~tain any initiator; or with a thi-rd seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the second seeding product, contain an initiator which is sol-uble in organic material.
-- Using a first seeding product, prepared by poly-merization in microsuspension, in which the polymer particles contain an initiator soluble in organic materlal, with a second seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the f.irst seeding product, contain an ini.tiator soluble in lV8Z~7 o.rg~nic ~aterial; either ~i~h a thlrd seedir.g pro~uct, pre~ared by polymeri~ation in emulsion or in microsuspension, in ~hieh th~ polymer particles, which are ~iner than those o the second ~e~diny product, do not contain any initiator; or with a third S seeding product, prepared by polyrnerization in microsuspension, in whieh the polymer particles, which are finer than those o~
the second seeding product, contain an initiator which is sol-uble in organic material.
- Using a first seeding product, prepared by polymer-ization in microsuspension, in which the polymer particles con~
tain an initiator soluble in organic material, with a seeond seeding product, prepared by polymerization in emulsion or in mierosuspension, in which the polymer particles, which are larger than those of the fi.rst seeding produet, do not eontain any initiator.
- Using a first seeding produet, prepared by polymer-ization in microsuspension, in which the polymer partieles eon-tain an initiator soluble in organie material; either with a seeond seeding product, prepared by polymerization in emulsion or in mierosuspension, in whieh the polymer particles, which are larger than those of the first seeding product, do not eon-tain any initiator; or with a seeond seeding product, prepared by polymerization in mierosuspension, in which the polymer par-tieles, which are larger than those of the first seeding produet, eontain an initiator soluble in organic material; and with a third seeding produet, prepared by polymerization in emulsion or in mierosuspension, in which the polymer particles, whieh ara larger than those of the seeond seeding product, do not contain any initiator.
- ~sing a first seeding product, prepared by ~.()8284 7 po:Lymerization in microsuspension, in ~lich the polymer par-ticles contain an initiator soluble in organic material; with a ~second seeding product, prepared by polymerizatlon in emul--sicn or in microsuspension, in which the polymer particles, which are finer than ~hose of the first seeding product, do not contain any initiator; and with a third seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are larger than those of the first seeding product, do not contain any initiator.
In a preferred embodiment, a seeding product, pre-pared by polymerization in microsuspension, in which the poly-mer particles contain an initiator, is used with a seeding product prepared by polymerization in emulsion, in which the polymer particles, which are finer than those of the first seeding proauct, do not con~ain any initiator.
The proportions of seeding products relative to one another and the total quantity of seeding products are select-ed so that the quantity of organo-soluble initiator present in the particles of polymer is sufficient to effect polymerization or copolymerization without any complementary addition of ini-~
tiator.
The quantity of water required for polymeriz.ation according to the invention must be such that the initial poly-~ler concentration of the seeding products plus the vinyl chlor--ide, with or without copolymerizable monomer, is from 20 to80% and preferably 45 to 75% by weight of the reaction mi~ture, allowing for the water content of the seeding products.
In order to improve the stabi.];ity of the microsus-pension, it may be advantageous to add,before and/or during polymerization, àt least one anionic emulsifier, possibly ~()82~
assoclated '.!ith at 1~5. onQ non-ion c ~ulsifi2 . The aniollic emulsifiers are preferably soaps of fatty acids, alkyl sul-phates, alkyl sulphonates, alXyl aryl sulphonates, vinyl sul-phonates, allyl sulphonates, alkyl su]phosuccinates and alka-line alkyl phosphates; the non-ionic emulsifiers are prefer-ably polycondensates of ethylene or propylene oxide on various hydroxylated organic compounds. The emulsifier may be the same as that or those used in the preparation of the seeding products.
The quantities of emulsifier may be up to 3% by weight of the vinyl chloride or mixture of vinyl chloride and copoly-merizable monomer. These are the quantities generally employed to obtain a usefu] effect in the reaction. However, quantities outside the above limits could be used without going beyond the ~cope of the invention, since the only function of the emulsi-fiers is to stabilize the microsuspension and they have no effect on the size of the particles.
The reaction medium is heated under autogenous press-ure to the polymerization temperature determined by the propsr-ties of the desired vinyl chloride polymer, depending on themolecular weights. The temperature is generally from 10 to 85C and preferably from 30 to 70C.
In order to accelerate polymerization it is recGmmend-ed to activate the initiator, included in the particles of the first seeding product and/or of the other seeding products, with a metal complex which is soluble in organic material and which is formed throughout the polymerization process by re-action between a water-soluble metal salt and a complexing agent which is introduced gradua]ly, as described in Canadian application Ser. ~0.201,886 , filed June 7, 1974 . The metal salt is employed in quantities such that the molar ratio of metal salt to initiator is from 0.1 to 10/1. The metal of the salt is represented by iron, copper, cobalt, nickel, zinc, tin, titanium, vanadium, manganese, chromium and silver. The complexiny agent is represented by mono- or poly-carboxylic and aJ.kyl phosphoric acids; lactones; ketones and carbazones.
It is used in proportions which may reach molar stoichiometry relative to the metal salt.
The process of polymerization in microsuspension, as described above, may obviously be carried out continuously.
Apart from the important advantages of the invention such as: minimal consumption of initiator; a reaction which is more regular and possibly shorter than in conventional process-es; and virtually no incrustation of the reaction zone, thus ~acilitating the heat exchanges which are necessary to obtain uniform polymerization, there are also more particular advan-tages: viz. that the invention gives a microsuspension with a high polymer concentration of up to 75% by weight and with great fluidity; this gives a concentration of 20 to 75% by weight; resulting in better exploitation of the polymerizing and separating means; and that it leads to excep~ional repro-ducibility of the sizes of particles contained in ~he latex obtained.
Latices thus prepared contain at least two popula-tions of particles of different average diameters. Thus, when two seeding products are used, the two poE~Ilations obtained have average diameters which, for the larger particles, range fro~ 0.4 to ~.5 ~m and, for the finer particles, from 0.08 to 1 ~m, in a diameter ratio of larger/finer of 1 to 20/1 and a weight ratio of 0.1 to 10/1. Similarly, when three seeding 1082l~4~
prod~cts ~re u~ecl, three poptllations are oktained, with ave--age (li~ eters ranginy from ~.~ to 2.5 ~m for the lar~Jer par-ti~les, froo 0.15 to l ~Im for the mediulll ones and ~rom 0.05 to 0.~ um for th~ finer ones. The diameter ratios o~ large particles/medium particles and of medium particles/fine par-ticles, which may be similar or different, range from l to 20/l, and the weight ratios of large particles/medium parti-cles and of medium particles/fine particles, which may be similar or different, range from 0:1 to ~0/l.
The diameters and weight ratios, within the above limits, are selected according to the conditions of use for the polymers formed, such as rheological properties of plasti-s019 or suitability for extrusion.
The particles of different average diameters result fxom enla.rgement of the particles of seeding products. By application of present-day knowledge, the particles of seed-ing products containing initiator should undergo an enlarge-ment as defined in French Patent No. 1,485,547; on the other hand, enlargement should be zero for particles of seeding products not containiny any initiator. Applicants have found the enlargement of particles containing an initiator to be less than expected, whereas particles not containing any ini-tiator undergo an enlargement which is not negligible, yet which is proportionally less than that of particles contain-ing an initiator; this enlargement complies neither with thelaw of enlarge~lent covering polymerization in microsuspension nor with the law covering polymerization in emulsion.
The vinyl chloride polymers prepared by the method of the invention are sepa^ated from the polymerizing medium 0 by any known methods such as filtration; co~gulation and 108Z~47 d7raining; ~aling; _cntri~.lg~l dccantatiorl; and a~omi~ation.
The invention also concernC the polymers thus ob-tained, which are in the form of powders particularly suitable for prepar;llg plastisol: ha~irlg Newtonlan or pseudoplastic behavior with a very low plasticizer content of up to 25 parts by weight of plastici7.er per 100 parts by weight of polymer, and a low viscosity which enables coatings to be applied at very high speed.
The polymers and copolymers of the invention are applicable to the manufacture of sheets, films, threads, hollo~
bodies, cellular materials or articles molded by calendering, extrusion, blow extrusion, injection or casting; they may also be used to obtain coated coverings, cellular materials or articles molded by any known methods of using plastisols:
coating, rotation molding or di~piny (trempage).
Some examples will now be given by way of illustra-tion and not by way of limitation of the invention:
ExamPle 1 PreParation of seedinq latex 1 in microsuspension.
The following are mixed:
- 40 kg of vinyl chloride, - 0.5 kg of lauroyl peroxide, - 4 kg of a lOo/o by weight aqueous solution of sodium dodecylbenzenesulphonate, - enough water .o bring the vinyl chloride concentra-tion to 43% by weight.
The mixture is homogenized to form a micros~spension which is then placed in a 120 liter autoclave. It is heated to 52C under autogenols pressure.
When the pressure has dropped, i.e. after 9 hours, 1082~4t7 the unreact~ lnyl chlorid2 i5 deg~ssed. The latex is ob-t:ainecl with a polyvinyl chloride concelltration of 4~/O by weight; i~s particles 'nave an average diameter of 0.4~um and contain 1~5% by weiyht of lauroyl peroxide relative to the polymer Preparation of seedinq latex 2 in emulsion The following are placed in a 120 liter autoclave:
- 60.6 kg of water, - 2.60 kg of a 10% by weight aqueous solution of sodium tetradecylsulphonate, - 0.053 kg of ammonia at 22 Baume~
- 52 kg of vinyl chloride.
The mixture is heated to 52C under autogenous pressure and this temperature is maintained throughout the operation~ As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced. 15 minutes later, 4.75 liters o a l~/o aqueous solution of sodium tetradecylsulphon-ate is added continuously at a rate of 0.5 liter/hour. After 9-1/2 hours at 52C~ the unreacted vinyl chloride is degassed.
The latex obtained has a polymer concentration of 40.2% by weight and a particle diameter of 0.12 ~m. The particles do not contain any initiator.
PolYmerization The following are placed in a 120 liter autoclave:
- 33.2 kg of water, - 5.7 kg of latex 1, i.e. 2.3 Xg of polyvinyl chlor-ide containing 34.5 g of lauroyl peroxide,
The polymers of the various seeding products in one and the same operation may be identical or different.
The use of a vinyl polymer other than vinyl chloride as a seedin~ product may make it possible to improve certain ~08Z84!7 mech~nic~l prOpQrties or the suitability of the resul'ant poly-mers for processing such as extrusion or calendering.
~rhe ~irst seeding product nccessary for polymeriæa-tion is prepared by conventional methods of polymerization in microsuspension. It is in the form of a dispersion of parti-cles of poly~er with an average diameter from 0.05 to 1.5jum and preferably from 0.2 to 1 ~m.
A method of preparing the first seeding product com-prises using water, a vinyl monomer or a mixture of vinyl mono-mers, an initiator soluble in organic material and an anionic emulsifier possibly associated with a non~ionic emulsifier. ~
The monomer or monomers are finely dispsrsed in the water with the aid of a powerful mechanical means such as a colloid mill, a high speed pump, a vibrating agitator or an ultxasonic ma-chine. The micxosuspension obtained is then heated under auto-genous pressure and with moderate agitation to a temperature generally from 30 to 65C. When the pressure has dropped, the reaction is stopped and the unconverted monomer or mono-mers are degassed.
The initiators which are soluble in organic material and which are to be used in preparing the seeding product are represented by organic peroxides such as diacyl paroxides;
among these mention should be made of lauroyl, decanoyl and caproyl peroxides, tertio'~utyl diethylperacetate, diethyl-hexyl percarbonate and diacetyl peroxide.
The choice of the initiator soluble in organic mater-ial depends on the speed at which it decomposes at the temper-ature used for the reaction. The initiator must in fact be reactive enough for normal ~uantities, of the crder of 0~1 to 3% by weight relative to the monom r or mixture o~ monomers, ~O~Z~7 to enable t}.e se~di~g produ~t to be prepared within periods of 4 to 20 h~l~s. However, the decomposing speed of the initia-tor should not be too high, so that the ~lantity oE initiator decomposed in preparing thc seeding product is not more than half the quantity of initiator used. It is therefore import-ant to select an initiator with a half-life time such that the proportion of initiator destroved in preparing the seeding product is from 5 to 50O/o by weight of all the initiator used.
In cases where several of euch initiators are used, it is advantageous to choose ones of different reactivity; the most reactive initiators are active chiefly during the prepar-ation of the seeding product, whereas the less reactive initiat-ors are active meinly during the seeded polymerization of the vinyl chloride or of the mixture of vinyl chloride and copoly merizable monomer.
The other seediny product or products are in the form of dispersions of particles of polymer, which may or may not contain an initiator; their average diameters, which differ from one another and from that of the first seeding product, are from 0.02 to 1.5 ~m and preferably from 0.02 to 0.8 ~m.
For example, in cases where there are only two seeding products, the average diameter of the particles of the second seeding product is from 0.05 to 1.5,um and preferably from 0~5 to 0.8 ~m; and in cases where there are three seeding products, the average diameter of the particles ofthe second seedin~ product is from 0.05 to 1.5 ~Im and preferably from 0.05 to 0.8 ~m, and the average diameter of the particles of the third seeding product is from 0.02 to 0.8 ~m and preferably from 0.02 to 0.5 ~m.
These dispersions of particles may be obtained by 108284r7 conventio;lal rl~tllods of polymeri~ation in microsusp~nsion or in cmul~ion.
The preparation o~ the seeding product or products, other than the first one, when carried out by polymerization in microsuspension, takes place as described above, but there is a greater degree of homogenization if the particles to be obtained are very small. In the method of the invention it is generally more advantageous to use one or more seeding products, other than the first, whicn do not contain any initiator. They are then polymerized with a quantity of initiator such that at least 8~/o by weight of the initiator is destroyed during the reaction.
Preparation of the seeding product or products, other than the first one, when carried out by polymerization in emul-sion, comprises using water, a vinyl monomer, either alon~ orassociated with a copolymerizable monomer, a water-soluble initiator and an anionic emulsifier, possibly associated with a non-ionic emulsifier.
The size of the particles is regulated by the usual methods suitable for polymerization in emulsion, e.g. by care-fully choosing the nature and quantity of emulsifier used, by using seeds and by adjusting the agitating speed.
The reaction mixture is heated under autogenous pressure and with moderate agitation to a temperature from 30 to 65C. When the pressure has dropped, the reaction is stop-ped and the unconverted monomer or monomers are degassed.
The water-soluble initiators required for preparing these seeding products are generally represented by hydrogen peroxide, persulphates of alkali metals or of ammonium, possibly associated with water-soluble reducing agents, such ~082~4!7 as ~ulphites or bi~ulphites of alkali metals. The quantities used vary greatly, dep~nding on the initiating system chosen ancl a~e just sufficient to insure polymerization within periods of 4 to lO hours.
In polymerization according to the invention, the total quantity of the various seeding products used must be such that the quantity of polymers contained therein is 1 to 5~/O by weight of the sum of vinyl chloride (with or without co-monomer to be polymerized) plus seeding polymers. A quantity of over 50% of seeding polymers can be used but is of little interest, for it is then very large relative to the vinyl chloride or mixture of vinyl chloride and copolymerizable monomer, and the advantages of the invention are thus mini-mized. A quantity of less than 1% of seeding polymers i5 also of very little intere9t, for the quantity of reactive initiator contained in the first seeding polymer or in two or more seed-ing polymers is then very small and does not, in practice, enable the vinyl chloride or mixture of vinyl chloride and copolymerizable monomer to be polymerized. It is in fact the excess initiator in the first seeding polymer or in two or mo~e seeding polymers that very effectively initiates polymerization of the vinyl chloride or mixture of vinyl chloride and copoly-merizable monomer, by setting up a regular reaction speed, as was shown in French Patent ~o. l,485,547.
The proportion of the first seeding polymer to the other seeding polymer or pol~mers, which depends on the com-position of the polymer to be obtained, is from 95/5 to 5/95.
Thus there are several possible ways of carrying out sesded polymerization. Sone examples of these are:
- Using a first seeding produc~, prepared by . ~-108Z8~Y7 pol~m~riz~tion in microsuspension, in which the polymer parti-clcs contain an initiator soluble in organic material; either witll a second seeding ~roduct, prepared by polymerization in ~mu:Lsion or in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, do not contain any initiator; or with a second seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, contain an initiator soluble in organic material - Using a first seeding product, prepared by poly-merization in microsuspension, in which the polymer paxticles contain an initiator soluble in organic material, with a second seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are finer than those of the first seeding product, do not contain any initiator: either with a third seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are finer than those of the second seeding product, do not co~tain any initiator; or with a thi-rd seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the second seeding product, contain an initiator which is sol-uble in organic material.
-- Using a first seeding product, prepared by poly-merization in microsuspension, in which the polymer particles contain an initiator soluble in organic materlal, with a second seeding product, prepared by polymerization in microsuspension, in which the polymer particles, which are finer than those of the f.irst seeding product, contain an ini.tiator soluble in lV8Z~7 o.rg~nic ~aterial; either ~i~h a thlrd seedir.g pro~uct, pre~ared by polymeri~ation in emulsion or in microsuspension, in ~hieh th~ polymer particles, which are ~iner than those o the second ~e~diny product, do not contain any initiator; or with a third S seeding product, prepared by polyrnerization in microsuspension, in whieh the polymer particles, which are finer than those o~
the second seeding product, contain an initiator which is sol-uble in organic material.
- Using a first seeding product, prepared by polymer-ization in microsuspension, in which the polymer particles con~
tain an initiator soluble in organic material, with a seeond seeding product, prepared by polymerization in emulsion or in mierosuspension, in which the polymer particles, which are larger than those of the fi.rst seeding produet, do not eontain any initiator.
- Using a first seeding produet, prepared by polymer-ization in microsuspension, in which the polymer partieles eon-tain an initiator soluble in organie material; either with a seeond seeding product, prepared by polymerization in emulsion or in mierosuspension, in whieh the polymer particles, which are larger than those of the first seeding product, do not eon-tain any initiator; or with a seeond seeding product, prepared by polymerization in mierosuspension, in which the polymer par-tieles, which are larger than those of the first seeding produet, eontain an initiator soluble in organic material; and with a third seeding produet, prepared by polymerization in emulsion or in mierosuspension, in which the polymer particles, whieh ara larger than those of the seeond seeding product, do not contain any initiator.
- ~sing a first seeding product, prepared by ~.()8284 7 po:Lymerization in microsuspension, in ~lich the polymer par-ticles contain an initiator soluble in organic material; with a ~second seeding product, prepared by polymerizatlon in emul--sicn or in microsuspension, in which the polymer particles, which are finer than ~hose of the first seeding product, do not contain any initiator; and with a third seeding product, prepared by polymerization in emulsion or in microsuspension, in which the polymer particles, which are larger than those of the first seeding product, do not contain any initiator.
In a preferred embodiment, a seeding product, pre-pared by polymerization in microsuspension, in which the poly-mer particles contain an initiator, is used with a seeding product prepared by polymerization in emulsion, in which the polymer particles, which are finer than those of the first seeding proauct, do not con~ain any initiator.
The proportions of seeding products relative to one another and the total quantity of seeding products are select-ed so that the quantity of organo-soluble initiator present in the particles of polymer is sufficient to effect polymerization or copolymerization without any complementary addition of ini-~
tiator.
The quantity of water required for polymeriz.ation according to the invention must be such that the initial poly-~ler concentration of the seeding products plus the vinyl chlor--ide, with or without copolymerizable monomer, is from 20 to80% and preferably 45 to 75% by weight of the reaction mi~ture, allowing for the water content of the seeding products.
In order to improve the stabi.];ity of the microsus-pension, it may be advantageous to add,before and/or during polymerization, àt least one anionic emulsifier, possibly ~()82~
assoclated '.!ith at 1~5. onQ non-ion c ~ulsifi2 . The aniollic emulsifiers are preferably soaps of fatty acids, alkyl sul-phates, alkyl sulphonates, alXyl aryl sulphonates, vinyl sul-phonates, allyl sulphonates, alkyl su]phosuccinates and alka-line alkyl phosphates; the non-ionic emulsifiers are prefer-ably polycondensates of ethylene or propylene oxide on various hydroxylated organic compounds. The emulsifier may be the same as that or those used in the preparation of the seeding products.
The quantities of emulsifier may be up to 3% by weight of the vinyl chloride or mixture of vinyl chloride and copoly-merizable monomer. These are the quantities generally employed to obtain a usefu] effect in the reaction. However, quantities outside the above limits could be used without going beyond the ~cope of the invention, since the only function of the emulsi-fiers is to stabilize the microsuspension and they have no effect on the size of the particles.
The reaction medium is heated under autogenous press-ure to the polymerization temperature determined by the propsr-ties of the desired vinyl chloride polymer, depending on themolecular weights. The temperature is generally from 10 to 85C and preferably from 30 to 70C.
In order to accelerate polymerization it is recGmmend-ed to activate the initiator, included in the particles of the first seeding product and/or of the other seeding products, with a metal complex which is soluble in organic material and which is formed throughout the polymerization process by re-action between a water-soluble metal salt and a complexing agent which is introduced gradua]ly, as described in Canadian application Ser. ~0.201,886 , filed June 7, 1974 . The metal salt is employed in quantities such that the molar ratio of metal salt to initiator is from 0.1 to 10/1. The metal of the salt is represented by iron, copper, cobalt, nickel, zinc, tin, titanium, vanadium, manganese, chromium and silver. The complexiny agent is represented by mono- or poly-carboxylic and aJ.kyl phosphoric acids; lactones; ketones and carbazones.
It is used in proportions which may reach molar stoichiometry relative to the metal salt.
The process of polymerization in microsuspension, as described above, may obviously be carried out continuously.
Apart from the important advantages of the invention such as: minimal consumption of initiator; a reaction which is more regular and possibly shorter than in conventional process-es; and virtually no incrustation of the reaction zone, thus ~acilitating the heat exchanges which are necessary to obtain uniform polymerization, there are also more particular advan-tages: viz. that the invention gives a microsuspension with a high polymer concentration of up to 75% by weight and with great fluidity; this gives a concentration of 20 to 75% by weight; resulting in better exploitation of the polymerizing and separating means; and that it leads to excep~ional repro-ducibility of the sizes of particles contained in ~he latex obtained.
Latices thus prepared contain at least two popula-tions of particles of different average diameters. Thus, when two seeding products are used, the two poE~Ilations obtained have average diameters which, for the larger particles, range fro~ 0.4 to ~.5 ~m and, for the finer particles, from 0.08 to 1 ~m, in a diameter ratio of larger/finer of 1 to 20/1 and a weight ratio of 0.1 to 10/1. Similarly, when three seeding 1082l~4~
prod~cts ~re u~ecl, three poptllations are oktained, with ave--age (li~ eters ranginy from ~.~ to 2.5 ~m for the lar~Jer par-ti~les, froo 0.15 to l ~Im for the mediulll ones and ~rom 0.05 to 0.~ um for th~ finer ones. The diameter ratios o~ large particles/medium particles and of medium particles/fine par-ticles, which may be similar or different, range from l to 20/l, and the weight ratios of large particles/medium parti-cles and of medium particles/fine particles, which may be similar or different, range from 0:1 to ~0/l.
The diameters and weight ratios, within the above limits, are selected according to the conditions of use for the polymers formed, such as rheological properties of plasti-s019 or suitability for extrusion.
The particles of different average diameters result fxom enla.rgement of the particles of seeding products. By application of present-day knowledge, the particles of seed-ing products containing initiator should undergo an enlarge-ment as defined in French Patent No. 1,485,547; on the other hand, enlargement should be zero for particles of seeding products not containiny any initiator. Applicants have found the enlargement of particles containing an initiator to be less than expected, whereas particles not containing any ini-tiator undergo an enlargement which is not negligible, yet which is proportionally less than that of particles contain-ing an initiator; this enlargement complies neither with thelaw of enlarge~lent covering polymerization in microsuspension nor with the law covering polymerization in emulsion.
The vinyl chloride polymers prepared by the method of the invention are sepa^ated from the polymerizing medium 0 by any known methods such as filtration; co~gulation and 108Z~47 d7raining; ~aling; _cntri~.lg~l dccantatiorl; and a~omi~ation.
The invention also concernC the polymers thus ob-tained, which are in the form of powders particularly suitable for prepar;llg plastisol: ha~irlg Newtonlan or pseudoplastic behavior with a very low plasticizer content of up to 25 parts by weight of plastici7.er per 100 parts by weight of polymer, and a low viscosity which enables coatings to be applied at very high speed.
The polymers and copolymers of the invention are applicable to the manufacture of sheets, films, threads, hollo~
bodies, cellular materials or articles molded by calendering, extrusion, blow extrusion, injection or casting; they may also be used to obtain coated coverings, cellular materials or articles molded by any known methods of using plastisols:
coating, rotation molding or di~piny (trempage).
Some examples will now be given by way of illustra-tion and not by way of limitation of the invention:
ExamPle 1 PreParation of seedinq latex 1 in microsuspension.
The following are mixed:
- 40 kg of vinyl chloride, - 0.5 kg of lauroyl peroxide, - 4 kg of a lOo/o by weight aqueous solution of sodium dodecylbenzenesulphonate, - enough water .o bring the vinyl chloride concentra-tion to 43% by weight.
The mixture is homogenized to form a micros~spension which is then placed in a 120 liter autoclave. It is heated to 52C under autogenols pressure.
When the pressure has dropped, i.e. after 9 hours, 1082~4t7 the unreact~ lnyl chlorid2 i5 deg~ssed. The latex is ob-t:ainecl with a polyvinyl chloride concelltration of 4~/O by weight; i~s particles 'nave an average diameter of 0.4~um and contain 1~5% by weiyht of lauroyl peroxide relative to the polymer Preparation of seedinq latex 2 in emulsion The following are placed in a 120 liter autoclave:
- 60.6 kg of water, - 2.60 kg of a 10% by weight aqueous solution of sodium tetradecylsulphonate, - 0.053 kg of ammonia at 22 Baume~
- 52 kg of vinyl chloride.
The mixture is heated to 52C under autogenous pressure and this temperature is maintained throughout the operation~ As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced. 15 minutes later, 4.75 liters o a l~/o aqueous solution of sodium tetradecylsulphon-ate is added continuously at a rate of 0.5 liter/hour. After 9-1/2 hours at 52C~ the unreacted vinyl chloride is degassed.
The latex obtained has a polymer concentration of 40.2% by weight and a particle diameter of 0.12 ~m. The particles do not contain any initiator.
PolYmerization The following are placed in a 120 liter autoclave:
- 33.2 kg of water, - 5.7 kg of latex 1, i.e. 2.3 Xg of polyvinyl chlor-ide containing 34.5 g of lauroyl peroxide,
- 3.5 kg of latex 2, i.e. 1.4 kg of polyvinyl chlox-ide, - 1.5 kg of a l~/o by weight aqueous solution of .
1(~8~7 S~ iU-[I do~ )erlæen~ s-l].~ onate, - 55 kg of vinyl chloride.
The mixture is agit:ated, ~1ith th~ agitator at S0 revolutions/min. and heated to 52C. 3 hours later, 2.5 kg of a l~/o by weight aqueous solution of sodium dodecylbenzene sulphonats is added.
After 18 hours' reaction, a drop in pressure is ob-served. When the pressure has dropped 2 bars, the unreacted vinyl chloride is degassed. A latex is obtained with a polymer concentration of 54% by weight and a viscosity of 38 cp.
The weight of crusts in the autoclave is only 300 g.
Particle size analysis of the latex obtained shows the polymer to be made up of two populations of particles with average diameters of 0.20 ~m and 0.98 ~m respectively. An in-cr~ase in the ~ize of thJ3 particles of l~tex 2 is noted, al-though they do not contain any initiator. The fine particles represent 25% by weight of the polymer.
The latex obtained is atomized, the powder obtained crushed, and a plastisol prepared by mixing lO0 parts by weight of polymer and 40 parts by weight of dioctyl phthalate. The rheological properties of the plastisol are measured:
B - firstly with the aid of a rotary r~eometer of the Brookfield RTV type (needle ~o. 6, 20 revs/minute, measuring and conditioning at 25C); the results are given in table l;
- secondly with the aid of a Severs extrusion-type rheometer (conditioning 2 hours at 25C); the results are set out in table 2.
3o g~ ~r ~ ~è ,~ O~ -16-T~l,E 1.
Brook~ield Viscosity ~ __ _ ___ Conditioning ~t 25C viscosity hours polses 0.5 : 210 24 ~40 The table shows that, although the plastisol contains little plasticize~ its viscosity is low and it develops slo~;ly with the passage of time.
TABLE 2.
Severs Viscosity Speed gradient Viscosity ;sec-l poises . . ~
s 235 308 15 , ~80 280 .. .. _ _ _ A ~tudy of the table reveals the surprising fact that the viscosity of the plastisol diminishes as the speed gradient increases; this is charac-teristic of a slight pseudo-plasticity of the plastisol, which makes it easier to use.
A plastisol consisting of 50 parts by weight of di-octylphthalate per 100 parts by weight of polyvinyl chloride also has pseudoplastic behavir that is to say, viscosity diminishes as the speed gradient increases.
For purposes of comparison three tests are carried out, with one seeding latex, according to prior art.
Test A in which the procedure is as above, but with proportions of reagents such that a latex of similar concen-tration is obtained.
~17-l()fl2~47 ~he fol~wing are placed in ~he re~Lor:
- 32.4 kg of water, - 6.9 kg of latex 1, i.e. 2.75 ky of polyvinyl chloridc, ~ 1.5 ky of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
The reaction is carried out under the same conditions.
The drop in pressure is observed after 18 hours. After degass-ing, a precipitated polymer is obtained in the reactor; it is impossible to recover this by conventional separating processes.
Test B carried out like test A but with an agitator speed of 30 revs/min. The drop in pressure is observed after 22 hours. The latex obtained has a polymer concentration of 54.5% by weight and a viscosity of 500 cp. Th~ weight o crusts in the reactor is 2 kg.
Particle size analysis of the latex shows that there is only one population of particles, with an average diameter of 1.05~um~
Atomization of the latex is difficult. The product ~r ~;~o/~
B obtained is crushed and two plaoticole are prepared. The re-sults are given in table 3.
3o ~382~7 TABEE 3.
}'L.A~'r I S OL
: P V C : ~ 0 P : Rheology : par~s by weight : parts by welght:
:
: 100 : 40 : Impossible to put : : : into paste form. A
: : : greatly dilatant, : : : heterogeneous mastic :
is obtained.
: 100 : 50 : Severs Viscosity : : : Gradient : Viscosity :
. sec~l poises : : : 187 770 : : : 255 860 Comparison of tests A and B and example 1 show the improvement provided by the method of the invention in obtain-ing latex with a high polymer concentrationand low viscosity.It also shows that the products of the process give plastisols of gretter fluidity for a low plasticizer content, enabling coatings to be applied at high speed.
Test C. If in text B, at high concentration, the proportion of initiator in the seed polymer is increased or an activating system added in order tG increase the speed of the reaction, the reaction mixture becomes thermally unstable due to the poor coefficient of thermal exchange of the reactor under the conditions of agitation of the viscous medium. Con-trol of the temperature of the reactor is tnereby lost and thereaction races, giving a latex which is useless, the polymer not having the required molecular weight.
Example 2 __ Seeding latices 1 and 2 from example 1 are used in polymerization.
r~_~vlne~ c.c- n The ollowing are charged into a 120 liter autoclave:
- 28.6 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of polyvinyl chloride, - 3.5 kg of latex 2, i.e. 1.4 kg of polyvinyl chloride, - 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 2.7 g of copper sulphate, - 55 kg of vinyl chloride.
The reaction mixture is agitated, with the agitator at a speed of 50 revs/min, and heated to 52C.
Continuous introduction of 0.4 liter/hour of a 0.68 g/liter aqueous solution of ascorbic acid is started as soon as the temperature reaches 52C.
After 3 hours at 52C, 2.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate is added.
After 9 hours' reaction, a drop in pressure is ob-served. when pressure has dropped 2 bars, the addition of ascorbic acid is stopped and the unreacted vinyl chloride is degassed. A latex is obtained with a polymer concentration of 55% by weight and a viscosity of 40 cp.
The weight of crusts in the reactor is only 120 g.
c'5 Particle size analysis of the latex obtained shows the polymer to be made up of two polulations of particles. One constitutes 30% by weight of the polymer and the average dia-meter of the particles is 0.20~m; the other has an average particle diameter of 1 ~m and constitutes 70% by weight. The 3 growth of the particles of latex 2 is noted, although they did 1082~47 not contai.~ ny ini-Liator.
Thc latex is atomized and the polymer obtainea is converted into 2 plastisols, respectively containing 40 and 5~/, by weight of dioctyl phthalc,te ,~er 100 part~ by weight o~
polymer.
The rheological properties o~' the first plastisol are set out in tables 4 and 5 and those of the second plasti-sol in table 6.
TA8LE 4.
Brookfield Viscosity .
Conditioning at 25C :Viscosity -~
hours ' poises ~ 0,5 ' 180 . 24 300 , TABLE 5.
Severs Viscosity . Speed Gradient ,Vlscosity ~sec~l s poises 215 ~ 360 400 , 350 ~ 6~0 340 2~ This plastisol has very slightly ps~udoplastic behavior, as indicated by the decrease in viscosity with the speed gradient.
Comparison between tables 2 and 5, i.e. examp_es 1 and 2, shows that activation by -the initiator has virtually no effect on rheological properties; it influences onl~ the 1()8Z8~7 ~a~ltic~n sp~C~.
TAsLE 6.
Severs Viscosity 5. Speed Gradient ; Viscosity sec 1 poises .
ComParative test D. Polymerization in emulsion.
PreParation of seedinq latex 1 in emulsion.
The following are placed in a 120 liter autoclave:
- 61 kg of water, - 0.053 kg of ~mmonia at 22 Baume, - 2.6 kg of seeding latex 2 from example 1, i.e.
1,150 kg of polyvinyl chloride, - 50 kg of vinyl chloride.
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the operation. As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced and 15 minutes later a 10% by weight aqueous solution of sodium tetradecylsulphonate is added continuously at a rate of 0.55 liter/hour~ After 9-1/2 hours, the unreacted vinyl chloride is degassed. The latex obtained has a polymer concentration of 40.5% by weight with a particle diameter of 0.40 ~m.
Polymerizatio_ The following are placed in a 120 liter a~toclave:
w 45 kg of water, -2_-10~7 - O . 053 ~Y OL arlllnollia ~t 22C B~ume,
1(~8~7 S~ iU-[I do~ )erlæen~ s-l].~ onate, - 55 kg of vinyl chloride.
The mixture is agit:ated, ~1ith th~ agitator at S0 revolutions/min. and heated to 52C. 3 hours later, 2.5 kg of a l~/o by weight aqueous solution of sodium dodecylbenzene sulphonats is added.
After 18 hours' reaction, a drop in pressure is ob-served. When the pressure has dropped 2 bars, the unreacted vinyl chloride is degassed. A latex is obtained with a polymer concentration of 54% by weight and a viscosity of 38 cp.
The weight of crusts in the autoclave is only 300 g.
Particle size analysis of the latex obtained shows the polymer to be made up of two populations of particles with average diameters of 0.20 ~m and 0.98 ~m respectively. An in-cr~ase in the ~ize of thJ3 particles of l~tex 2 is noted, al-though they do not contain any initiator. The fine particles represent 25% by weight of the polymer.
The latex obtained is atomized, the powder obtained crushed, and a plastisol prepared by mixing lO0 parts by weight of polymer and 40 parts by weight of dioctyl phthalate. The rheological properties of the plastisol are measured:
B - firstly with the aid of a rotary r~eometer of the Brookfield RTV type (needle ~o. 6, 20 revs/minute, measuring and conditioning at 25C); the results are given in table l;
- secondly with the aid of a Severs extrusion-type rheometer (conditioning 2 hours at 25C); the results are set out in table 2.
3o g~ ~r ~ ~è ,~ O~ -16-T~l,E 1.
Brook~ield Viscosity ~ __ _ ___ Conditioning ~t 25C viscosity hours polses 0.5 : 210 24 ~40 The table shows that, although the plastisol contains little plasticize~ its viscosity is low and it develops slo~;ly with the passage of time.
TABLE 2.
Severs Viscosity Speed gradient Viscosity ;sec-l poises . . ~
s 235 308 15 , ~80 280 .. .. _ _ _ A ~tudy of the table reveals the surprising fact that the viscosity of the plastisol diminishes as the speed gradient increases; this is charac-teristic of a slight pseudo-plasticity of the plastisol, which makes it easier to use.
A plastisol consisting of 50 parts by weight of di-octylphthalate per 100 parts by weight of polyvinyl chloride also has pseudoplastic behavir that is to say, viscosity diminishes as the speed gradient increases.
For purposes of comparison three tests are carried out, with one seeding latex, according to prior art.
Test A in which the procedure is as above, but with proportions of reagents such that a latex of similar concen-tration is obtained.
~17-l()fl2~47 ~he fol~wing are placed in ~he re~Lor:
- 32.4 kg of water, - 6.9 kg of latex 1, i.e. 2.75 ky of polyvinyl chloridc, ~ 1.5 ky of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
The reaction is carried out under the same conditions.
The drop in pressure is observed after 18 hours. After degass-ing, a precipitated polymer is obtained in the reactor; it is impossible to recover this by conventional separating processes.
Test B carried out like test A but with an agitator speed of 30 revs/min. The drop in pressure is observed after 22 hours. The latex obtained has a polymer concentration of 54.5% by weight and a viscosity of 500 cp. Th~ weight o crusts in the reactor is 2 kg.
Particle size analysis of the latex shows that there is only one population of particles, with an average diameter of 1.05~um~
Atomization of the latex is difficult. The product ~r ~;~o/~
B obtained is crushed and two plaoticole are prepared. The re-sults are given in table 3.
3o ~382~7 TABEE 3.
}'L.A~'r I S OL
: P V C : ~ 0 P : Rheology : par~s by weight : parts by welght:
:
: 100 : 40 : Impossible to put : : : into paste form. A
: : : greatly dilatant, : : : heterogeneous mastic :
is obtained.
: 100 : 50 : Severs Viscosity : : : Gradient : Viscosity :
. sec~l poises : : : 187 770 : : : 255 860 Comparison of tests A and B and example 1 show the improvement provided by the method of the invention in obtain-ing latex with a high polymer concentrationand low viscosity.It also shows that the products of the process give plastisols of gretter fluidity for a low plasticizer content, enabling coatings to be applied at high speed.
Test C. If in text B, at high concentration, the proportion of initiator in the seed polymer is increased or an activating system added in order tG increase the speed of the reaction, the reaction mixture becomes thermally unstable due to the poor coefficient of thermal exchange of the reactor under the conditions of agitation of the viscous medium. Con-trol of the temperature of the reactor is tnereby lost and thereaction races, giving a latex which is useless, the polymer not having the required molecular weight.
Example 2 __ Seeding latices 1 and 2 from example 1 are used in polymerization.
r~_~vlne~ c.c- n The ollowing are charged into a 120 liter autoclave:
- 28.6 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of polyvinyl chloride, - 3.5 kg of latex 2, i.e. 1.4 kg of polyvinyl chloride, - 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 2.7 g of copper sulphate, - 55 kg of vinyl chloride.
The reaction mixture is agitated, with the agitator at a speed of 50 revs/min, and heated to 52C.
Continuous introduction of 0.4 liter/hour of a 0.68 g/liter aqueous solution of ascorbic acid is started as soon as the temperature reaches 52C.
After 3 hours at 52C, 2.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate is added.
After 9 hours' reaction, a drop in pressure is ob-served. when pressure has dropped 2 bars, the addition of ascorbic acid is stopped and the unreacted vinyl chloride is degassed. A latex is obtained with a polymer concentration of 55% by weight and a viscosity of 40 cp.
The weight of crusts in the reactor is only 120 g.
c'5 Particle size analysis of the latex obtained shows the polymer to be made up of two polulations of particles. One constitutes 30% by weight of the polymer and the average dia-meter of the particles is 0.20~m; the other has an average particle diameter of 1 ~m and constitutes 70% by weight. The 3 growth of the particles of latex 2 is noted, although they did 1082~47 not contai.~ ny ini-Liator.
Thc latex is atomized and the polymer obtainea is converted into 2 plastisols, respectively containing 40 and 5~/, by weight of dioctyl phthalc,te ,~er 100 part~ by weight o~
polymer.
The rheological properties o~' the first plastisol are set out in tables 4 and 5 and those of the second plasti-sol in table 6.
TA8LE 4.
Brookfield Viscosity .
Conditioning at 25C :Viscosity -~
hours ' poises ~ 0,5 ' 180 . 24 300 , TABLE 5.
Severs Viscosity . Speed Gradient ,Vlscosity ~sec~l s poises 215 ~ 360 400 , 350 ~ 6~0 340 2~ This plastisol has very slightly ps~udoplastic behavior, as indicated by the decrease in viscosity with the speed gradient.
Comparison between tables 2 and 5, i.e. examp_es 1 and 2, shows that activation by -the initiator has virtually no effect on rheological properties; it influences onl~ the 1()8Z8~7 ~a~ltic~n sp~C~.
TAsLE 6.
Severs Viscosity 5. Speed Gradient ; Viscosity sec 1 poises .
ComParative test D. Polymerization in emulsion.
PreParation of seedinq latex 1 in emulsion.
The following are placed in a 120 liter autoclave:
- 61 kg of water, - 0.053 kg of ~mmonia at 22 Baume, - 2.6 kg of seeding latex 2 from example 1, i.e.
1,150 kg of polyvinyl chloride, - 50 kg of vinyl chloride.
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the operation. As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced and 15 minutes later a 10% by weight aqueous solution of sodium tetradecylsulphonate is added continuously at a rate of 0.55 liter/hour~ After 9-1/2 hours, the unreacted vinyl chloride is degassed. The latex obtained has a polymer concentration of 40.5% by weight with a particle diameter of 0.40 ~m.
Polymerizatio_ The following are placed in a 120 liter a~toclave:
w 45 kg of water, -2_-10~7 - O . 053 ~Y OL arlllnollia ~t 22C B~ume,
- 4.10 kg of latex 1, i.e. 1.67 kg of polyvinyl chk~lide, - 2.55 kg of latex 2 from example 1, i.e. 1.02 ky of polyvinyl chloride, - 40 kg of vinyl chloride.
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the re-action. As soon as the mixture is at 52C, 0.025 kg of potass-ium persulphate is introduced. 15 minutes later, 5 liters of ~ 10% by weight aqueous solution of sodium dodecylbenzene sul-phonate is added continuously at a rate of 0.5 liter/hour.
After 10 hours' reaction, the unreacted vinyl chloride i9 degassed. The latex obtained has a polymer concentration of 15 420/o by we~yht. The weight of crusts in the reactor is 500 g.
Particle size analysis of the latex obtained shows the polymer to be made up of two populations of particles. One constitutes 39% by weight of the polymer, and the average diameter of its particles is 0.83 ~m;; the other has an average particle diameter of 0.34 ~m and constitutes 61% by weight.
The latex is atomized, then converted into plastisol as in example 1.
The rheological properties are as follows:
TABLE 7.
Brookfield Viecosity .
Conditioning at 25JC Viscosity :hours : poises I
24 `2000 10~3~7 I'ABLE 8.
Severs Viscosity .~
; Specd Gradient . Viscosity sec~l poises lgO 4200 Comparison between example 2 and test D shows the very great difference in particle size between the latices ob-tained by polymerization in microsuspension and in emulsion, and consequently the difference between the rheological proper-ties of plastisols formed from the polymers obtained from these latices.
Examples 3 to 9.
PolYmerization.
In each of the examples, a 120 liter autoclave is used, in which there are placed:
- a variable quantity of water,
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the re-action. As soon as the mixture is at 52C, 0.025 kg of potass-ium persulphate is introduced. 15 minutes later, 5 liters of ~ 10% by weight aqueous solution of sodium dodecylbenzene sul-phonate is added continuously at a rate of 0.5 liter/hour.
After 10 hours' reaction, the unreacted vinyl chloride i9 degassed. The latex obtained has a polymer concentration of 15 420/o by we~yht. The weight of crusts in the reactor is 500 g.
Particle size analysis of the latex obtained shows the polymer to be made up of two populations of particles. One constitutes 39% by weight of the polymer, and the average diameter of its particles is 0.83 ~m;; the other has an average particle diameter of 0.34 ~m and constitutes 61% by weight.
The latex is atomized, then converted into plastisol as in example 1.
The rheological properties are as follows:
TABLE 7.
Brookfield Viecosity .
Conditioning at 25JC Viscosity :hours : poises I
24 `2000 10~3~7 I'ABLE 8.
Severs Viscosity .~
; Specd Gradient . Viscosity sec~l poises lgO 4200 Comparison between example 2 and test D shows the very great difference in particle size between the latices ob-tained by polymerization in microsuspension and in emulsion, and consequently the difference between the rheological proper-ties of plastisols formed from the polymers obtained from these latices.
Examples 3 to 9.
PolYmerization.
In each of the examples, a 120 liter autoclave is used, in which there are placed:
- a variable quantity of water,
- 5.7 kg of latex 1 from example 1, i.e. 2.3 kg of i~
polyvinyl chloride, - a variable quantity or latex 2, the average dia-meters of the particles being different in each of the examples;
the difference between the average diameters of the particles is obtained by varying the ~uantity of emulsifier used at the beyinning of th~ preparation of latex 2 from example 1, - 0.55 kg of a l~/o by weight aqueous solution of sodium tetradecylsulphonate, - 4 g of copper sulphate, - 55 kg of vinyl chloride -~4-~O~
~r~he proc~dur2 i-, the same as in exaM~ie 2, except that 3.5 kg of the same solution of sodlum tetradecylsulphon-~tc i~ added during polymerization instead of the sodium do-decy~benæene sulphonate so]ution.
The variable data of the reaction and the results obtained are set out in table 9.
A study of the table shows the effect of the total quantity of seeding latices, the effect of the proportion of one of the seediny latices relative to the other, and the ef-fect of the particle diameter of the latices on the formatio~
of crusts during polymerization, and on the particle size of the latices obtained.
Example 10.
Example 2 is repeated, except that the quantity of water used for polymerization is 11.7 kg lnstead of 28.6 kg.
At the end of the reaction, the polymer concentra-tion of the latex is 67% by weight and its viscosity is 60 cp.
The weight of crusts in the autoclave i5 240 g.
The latex contains particles, 29% by weight of which have an average diameter of 0.19 ~m and 71% by weight of which have an average diameter of l ~m.
The latex thus obtained is divided into two portions.
- The first portion is atomized under normal condi-tions at low temperature. The powder obtained is crushed and converted into plastisol by mixing of 40 parts of diactyl phthalate per 100 parts of powder.
The rheological p~operties of the plastisol, measured as in example 1, are summarized in tables 10 and 11.
3o 1082~W7 ..... .......................... ................................... '.
C~ u) ~ O `D O ~
t`~ O O V7 N '~
..... ......................... ...................................
L~ ~ _~
1~ et 1~ ~ CO O N
00 ~ O O 00 ~ ~ O 1 1~
..... ......................... ...................................
U~ U) O~
I~ ~ ~ ~ _1 ~ C~ ~1 _1 ~D N O O ~C) Cl~ O O Cl~
N L~l N
...... .......................... ...................................
C~ ~0 ~
~ . . . .
_~ ~ ~ O O O ~ ~ O U~
N If~
, ...... .......................... ...................................
U~
U) N d' 00 d' o~ I ~ a~ ~
U7 ~ O ~ O g U~ 00 0 0 ~O
...... .......................... ...................................
C~
. Lr~ 00 O
~ t~ ~1 . 00 '7 ¢ ~ ~ O O O ~ ~ O u~
..... ......................... .....................................
, L~ 00 oo~
t~ . . ~ N
o o ~ o o n _ o o o N N U~ U) t,) ,,~
..... .......................... .....................................
b4 ~b4e b~ ~o ~ ee 0~
.Y ~ . ~~ .
111 O o\ rl .~_~ ~1 N
~1 0 V~ O ~ U) 4~
t~ ~ U~ h ~a~ o N N'' h h X rl ~ ) ~Q~ C) O ~,1 ,1 ,1 Q) a~V . ~ v ~3 ~~ O h ~ o ~ v) h h h . ~ ~ ~,1 ~ ~ ~ O ~~ ~ ~ O
C I I I ~ o ................................ ................................... .
1()82~7 TA~LE 10.
Brookfield Viscosity Conditioning at 25C Viscosity hours : poises 0.5 220 :
:24 : 460 :
TABLE 11.
Severs Viscosity . Speed gradient . Viscosity :sec : poises .
243 : 313 :
:830 : 272 This example shows the surprising fact that latices with a very high concentration and with low viscosity can be obtained without any crust formation.
- The second portion of the latex is atomized at a higher temperature. The powder obtained has polyvinyl chloride-particles with an average diameter of 113 ~m, an apparent mass per unit volume of 0.69 g/ml and a viscosity inaex of 117.
100 parts by weight of the polymer,thus obtained,are mixed with 0.5 part by weight of calcium stearate, 4 parts by weight or a lead stabilizer and 4 parts by weight o~ titani~m oxide. The composition is then studied with the aid of a BRABENDER extrusion recorder and a BRABENDER plastograph and compared with an identical composition prepared with a poly-vinyl chloride obtained by mass polymerization, with a viscos-ity index of 101~ - -10~284 7 T?le results are se-t out in table 12.
TABL~ 12 .
BRAs~wDER PLASTOGRAPEI BRAB~NDER E~;TRIJSION
. RECORDER
POLYMER Gelation : Gelation- Flow : Power : Diarneter .
time : torque : rate :consumed by: of extrud-: : : machine : ed product:
: : sec. m/g kg/h w mm :PVC in examEle 60 3,900 1.73 273 2.31 :Mass : PV~ : 600 2,350 1.62 233 2.53 swelling The vinyl polychloride obtained by the method of theinvention is found to gel more quickly, to be extruded slightly more rapidly and to show less swelling on emerging from the die than a polyvi~yl chloride prepared by mass polymerization.
Example 11.
- Seeding latex 1 in microsuspension is that prepared in example 1.
- Prepaxation of seedinq latex 2 in microsusPension.
The procedure is the same as in example 1, preparation of seeding latex 1, except that 8 kg of a 10% by weight aqueous solution of sodium dodecyl benzene sulphonate is used instead of 4 kg, and 0.04 kg of lauroyl peroxide is used instead of 0.~ kg. There is very fine homogenization.
The particles of latex obtained have an average dia-meter of 0.12 ~m and contain only 0.07% by weight of initiator.
-- Polymerization.
The following are placed in a 120 liter autoclave:
- 28.6 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of polyvinyl chloride, -2~3-~08Z8~Y7 -- 3.5 ky Or iat~x 2, i.e. 1.4 kg of polyvinyl chloride containiny only very little initiator, corresponding to O.OO~o~0 by weiyht of the monomer present, - 2.7 g of copper sulphate, - 1.5 lcg of a 10% by weight a~ueous solution of sodiurn dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
The reaction is carried out as in example 2. The polymer concentration o~ the latex obtained is 54% by weight lC and its viscosity is 60 cp. The weight of crusts is approxi-mately 100 g.
The polymer is made up of two populations of parti-cles with respective average diameters of 0.19 ~m and 1 ~m, the fine particles constituting 2~/o by weight.
An enlargernent of the particles of latex 2 was noted although its initiator content was virtually zero.
Example 12.
- ~reparation of seedinq latex 1 in microsuspension.
The preparation of seeding latex 1 in example 1 is repeated, but with homogenization such that the particle size of the latex is 0.48 ~m. The polymer concentration is 39.5%
by weight and the particles contain 1.5% by weight, relative to the polymer, of lauroyl peroxide.
- PreParation of seedinq latex 2 in microsusPension.
The preparatiDn of seeding latex 1 in example 1 is repeated, with homogenization such that the particle size of the latex is 0.1 ~m. The polymer concentration is 400/0 and the particles contain 1.5% by weight, relative to the polymer, of lauroyl peroxide.
- Polymerization.
1(18Z~W7 The ~ollowillg are placed in a 120 liter reactor:
- 31.2 kg of w~ter, - 1.5 kg of a 10% aqueous solution of sodium dodecyl-benzene sul~honate, - 9.9 kg of latex l, i.e. 3.9 kg of polyvinyl chloride,
polyvinyl chloride, - a variable quantity or latex 2, the average dia-meters of the particles being different in each of the examples;
the difference between the average diameters of the particles is obtained by varying the ~uantity of emulsifier used at the beyinning of th~ preparation of latex 2 from example 1, - 0.55 kg of a l~/o by weight aqueous solution of sodium tetradecylsulphonate, - 4 g of copper sulphate, - 55 kg of vinyl chloride -~4-~O~
~r~he proc~dur2 i-, the same as in exaM~ie 2, except that 3.5 kg of the same solution of sodlum tetradecylsulphon-~tc i~ added during polymerization instead of the sodium do-decy~benæene sulphonate so]ution.
The variable data of the reaction and the results obtained are set out in table 9.
A study of the table shows the effect of the total quantity of seeding latices, the effect of the proportion of one of the seediny latices relative to the other, and the ef-fect of the particle diameter of the latices on the formatio~
of crusts during polymerization, and on the particle size of the latices obtained.
Example 10.
Example 2 is repeated, except that the quantity of water used for polymerization is 11.7 kg lnstead of 28.6 kg.
At the end of the reaction, the polymer concentra-tion of the latex is 67% by weight and its viscosity is 60 cp.
The weight of crusts in the autoclave i5 240 g.
The latex contains particles, 29% by weight of which have an average diameter of 0.19 ~m and 71% by weight of which have an average diameter of l ~m.
The latex thus obtained is divided into two portions.
- The first portion is atomized under normal condi-tions at low temperature. The powder obtained is crushed and converted into plastisol by mixing of 40 parts of diactyl phthalate per 100 parts of powder.
The rheological p~operties of the plastisol, measured as in example 1, are summarized in tables 10 and 11.
3o 1082~W7 ..... .......................... ................................... '.
C~ u) ~ O `D O ~
t`~ O O V7 N '~
..... ......................... ...................................
L~ ~ _~
1~ et 1~ ~ CO O N
00 ~ O O 00 ~ ~ O 1 1~
..... ......................... ...................................
U~ U) O~
I~ ~ ~ ~ _1 ~ C~ ~1 _1 ~D N O O ~C) Cl~ O O Cl~
N L~l N
...... .......................... ...................................
C~ ~0 ~
~ . . . .
_~ ~ ~ O O O ~ ~ O U~
N If~
, ...... .......................... ...................................
U~
U) N d' 00 d' o~ I ~ a~ ~
U7 ~ O ~ O g U~ 00 0 0 ~O
...... .......................... ...................................
C~
. Lr~ 00 O
~ t~ ~1 . 00 '7 ¢ ~ ~ O O O ~ ~ O u~
..... ......................... .....................................
, L~ 00 oo~
t~ . . ~ N
o o ~ o o n _ o o o N N U~ U) t,) ,,~
..... .......................... .....................................
b4 ~b4e b~ ~o ~ ee 0~
.Y ~ . ~~ .
111 O o\ rl .~_~ ~1 N
~1 0 V~ O ~ U) 4~
t~ ~ U~ h ~a~ o N N'' h h X rl ~ ) ~Q~ C) O ~,1 ,1 ,1 Q) a~V . ~ v ~3 ~~ O h ~ o ~ v) h h h . ~ ~ ~,1 ~ ~ ~ O ~~ ~ ~ O
C I I I ~ o ................................ ................................... .
1()82~7 TA~LE 10.
Brookfield Viscosity Conditioning at 25C Viscosity hours : poises 0.5 220 :
:24 : 460 :
TABLE 11.
Severs Viscosity . Speed gradient . Viscosity :sec : poises .
243 : 313 :
:830 : 272 This example shows the surprising fact that latices with a very high concentration and with low viscosity can be obtained without any crust formation.
- The second portion of the latex is atomized at a higher temperature. The powder obtained has polyvinyl chloride-particles with an average diameter of 113 ~m, an apparent mass per unit volume of 0.69 g/ml and a viscosity inaex of 117.
100 parts by weight of the polymer,thus obtained,are mixed with 0.5 part by weight of calcium stearate, 4 parts by weight or a lead stabilizer and 4 parts by weight o~ titani~m oxide. The composition is then studied with the aid of a BRABENDER extrusion recorder and a BRABENDER plastograph and compared with an identical composition prepared with a poly-vinyl chloride obtained by mass polymerization, with a viscos-ity index of 101~ - -10~284 7 T?le results are se-t out in table 12.
TABL~ 12 .
BRAs~wDER PLASTOGRAPEI BRAB~NDER E~;TRIJSION
. RECORDER
POLYMER Gelation : Gelation- Flow : Power : Diarneter .
time : torque : rate :consumed by: of extrud-: : : machine : ed product:
: : sec. m/g kg/h w mm :PVC in examEle 60 3,900 1.73 273 2.31 :Mass : PV~ : 600 2,350 1.62 233 2.53 swelling The vinyl polychloride obtained by the method of theinvention is found to gel more quickly, to be extruded slightly more rapidly and to show less swelling on emerging from the die than a polyvi~yl chloride prepared by mass polymerization.
Example 11.
- Seeding latex 1 in microsuspension is that prepared in example 1.
- Prepaxation of seedinq latex 2 in microsusPension.
The procedure is the same as in example 1, preparation of seeding latex 1, except that 8 kg of a 10% by weight aqueous solution of sodium dodecyl benzene sulphonate is used instead of 4 kg, and 0.04 kg of lauroyl peroxide is used instead of 0.~ kg. There is very fine homogenization.
The particles of latex obtained have an average dia-meter of 0.12 ~m and contain only 0.07% by weight of initiator.
-- Polymerization.
The following are placed in a 120 liter autoclave:
- 28.6 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of polyvinyl chloride, -2~3-~08Z8~Y7 -- 3.5 ky Or iat~x 2, i.e. 1.4 kg of polyvinyl chloride containiny only very little initiator, corresponding to O.OO~o~0 by weiyht of the monomer present, - 2.7 g of copper sulphate, - 1.5 lcg of a 10% by weight a~ueous solution of sodiurn dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
The reaction is carried out as in example 2. The polymer concentration o~ the latex obtained is 54% by weight lC and its viscosity is 60 cp. The weight of crusts is approxi-mately 100 g.
The polymer is made up of two populations of parti-cles with respective average diameters of 0.19 ~m and 1 ~m, the fine particles constituting 2~/o by weight.
An enlargernent of the particles of latex 2 was noted although its initiator content was virtually zero.
Example 12.
- ~reparation of seedinq latex 1 in microsuspension.
The preparation of seeding latex 1 in example 1 is repeated, but with homogenization such that the particle size of the latex is 0.48 ~m. The polymer concentration is 39.5%
by weight and the particles contain 1.5% by weight, relative to the polymer, of lauroyl peroxide.
- PreParation of seedinq latex 2 in microsusPension.
The preparatiDn of seeding latex 1 in example 1 is repeated, with homogenization such that the particle size of the latex is 0.1 ~m. The polymer concentration is 400/0 and the particles contain 1.5% by weight, relative to the polymer, of lauroyl peroxide.
- Polymerization.
1(18Z~W7 The ~ollowillg are placed in a 120 liter reactor:
- 31.2 kg of w~ter, - 1.5 kg of a 10% aqueous solution of sodium dodecyl-benzene sul~honate, - 9.9 kg of latex l, i.e. 3.9 kg of polyvinyl chloride,
- 6.35 kg of seeding latex 2, i.e. 2.5 kg of poly-vinyl chloride, - 55 kg of vinyl chloride.
The reaction mixture is agitated, heated to 52C
under autogenous pressure and kept at that temperature through-out the reaction.
After 3 hours' reaction, 2.5 kg of a 10% by wei~,ht aqueous solution o sodium dodecylbenzene sulphonate is added to the mixture. The drop in pressure takes place after 12 hours' reaction. When it has dropped 2 bars, the unreacted vinyl chloride is degassed.
The polymer concentration of the latex obtained is 54% by weight. The weight of crusts is 500 g.
The two populations of particles forming the polymer have respective average diameters of 0.18~m and 0.99 ~m which constitute 29 and 71% of the weight.
Example 13 Example 8 is repeated except that the following are used for polymerization:
- 16.4 kg of water, - 52.25 kg of vinyl chloride and - 2.75 kg of vinyl acetate.
The latex obtained has a concentration of 58.1% by weight and a viscosity of 40 cp. The weight of crusts is low, -- ~0--- 108289~7 at 150 g. llle polyrncx ls made up of 22% by weight o~ particles ~it:h an a-~ex.lc3e diameter of O.Z2~m and 78% by wei~ht of parti-Cle9 with an average cliameter of 1.05 ~m.
The latex is atomized; the product obtained is a copolymer containing 3.6% by weight of ~-inyl acetate. The rheological properties of plastisols containing different quancities of dioctyl phthalate are gi~en in table 13.
TABLE l3.
:
: D O P : Brookfield : Severs :
:parts/100 : viscosity :(poises) Speed gradient : Viscosity :of polymer: 1/2 hour : 1 day : (sec~l) : (poises) :
280 660 : 100 ; 700 : : : (390 :(390 :100 :2~0 : : : (940 :(240 :
: : : (1000 : (70 : 60 : 30 35 : : : (2600 (58 A low viscosity plastisol containing 40 parts by ~0 weight of dioctyl phthalate per 100 parts by weight of vinyl chloride/vinyl acetate copolymer is found to be obtained; this is impossible with previous processes.
Example 1-~
- Seeding latex 1 used is that from exarnple 1.
- PreParation of seediny latex 2 in emulsion.
The procedure is eactly the same as in example 1.
The diameter o~ the particles obtained is 0.115 ~m.
- Polymerization'O
Example 2 is repeated.
At the end of the react~oll the concentration of the 1()8*~!7 ]a~ 54.g~0 ~-y w2icJht a~ld its viscosi~y is 40 cp. ~rhe weight of crusts in the autoclave is 150 g.
The polymer o tlle latex is made up of 69~/o by weight of particles with an average diameter of 0.98,um and 31% by weight o~ particles with an average diameter of 0.19 ~m.
Comparative tests E and F in emulsion with two seed-ing latices of the emulsion type.
- Preparation of seeding latex 1 in emulsion.
The procedure is like that followed in preparing the seeding latex in comparative test D of example 2.
- Preparation of seedinq latex 2 in emulsion. `~
e) The preparation of seeding latex 2 from example 1 is repeated, except that 1.04 kg of a 10% by weight aqueous colution of sodium tetradecylsulphonate is used instead of 2.6 ky, and no sodium tetradecylsulphonate is introduced during polymerization. The particle diameter of the latex obtained is 0.031 ~m.
f) The procedure is exactly the same as in e). The particle diameter of the latex obtained is 0.025~um.
Two polymerizations ~re carried out as follows, one with latex 2e and the other with latex 2f. The proportions are such that the weight ratio of the two populations of par-ticles and the diameter of the largest particles in the latex to be obtained are close to those of the latex in example 14.
The following are charged into a 25 liter autoclave:
- 8000 g of deionized water, - seeding latices 1 and 2 in varying quantities - vinyl chloride in a ~antity such that the weight of monomer and seeding polymer is 7000 g.
3 The mixture is agitated and heated to 52C. ~s soon ~0~284 7 as the rnixtllre t'eclC-n~S that temperatu~e, ~ g of ~onium per-sulphate is introduced. One hour la~el^, Z liters of a 1~75'~/o by weight aqueous solution of sodium dodecylbellzcne sulphonate is introduced continuously at a rate of 0.23 liter/hour.
When pressure is at 5 bar~" the unreacted monomer is degassed.
The operating data and results of tests E and F are ~ -summarized in table 14 and compared ~iih examples 2 and 14.
A study of this table shows that a slight difference in the particle diameters of seeding latices Z in polymeriza-tion in microsuspension results in virtually no differences in the particle size of the products obtained or in the rheologi-cal properties. On the other hand, an identical difference between the particle diam~ters of seeding latices 2 in poly-merizatJon in emulslon ~eads to significant differences in the particle size of the products obtained and consequently in their rheological properties. In t'mis case there is no reproducibility of the process.
3o ~08Zt~7 .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. ..
~r ~r 0~ u~ a~ o~ ~ o ~ ~ a~ l o ~ o ~ o ~ o , ~ o CO
~ ........ ...................... ................... ...................
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o ~ ~ o o l l r o ~ o o .. .. . . oU~
O q O N ~1 00 0 CO ~ I I
........ ........ ..................... ........... ..... ................ -O ~ O ~D ~ O
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................ ...................... .......................................
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~ o ~ .,~ ~rl ~I In ~: 1:~ 0 h ~ ~ ~ J~ :~ O
O ~ ) lll 1~ ,a ~4 o ~J
.~ ' ~'~1 g .4 ~ U~ ~rl ''~
~ 11 ~ I ", I o ~ ~ -o~ ~ 8 .~ l I I l ~ ~ P. .q ~ ~q , ~ ~ C~ ~, ~ ~ ~
, X ,~ o .,, ,, , .Y
2 ~ ~ ~ ~ ~ P.
~ P~ m ............. ...................... .......................................
108ZB~7 ~
- Pre~ ion of se~dinq l~ta~ 1 in microsuspension.
The preparation of seecling lal:ex 1 from example 1 is repe;lted with homogellization such that ~he average particle diameter of the latex is 0.25 ~m. The polymer concentration of the late~ obtained is 40O/o by wei~ht and the particles con-tain 1.5% by weight, relative to the polymer, of lauroyl per-oxide.
- Preparation of seedinq latex 2 in emulsion.
Procedure is the same as in comparative test D in example 2, but with 0.43 kg, instead of 2.6 kg. of seeding latex 2 from example 1, i.e. 0.190 kg of polyvinyl chloride.
The latex obtained has a polymer concentration of 40/O by weight, and the diameter of its particles is 0.74 ~m.
- PolYm~riY~ation~
The following are placed in a 120 liter autoclave:
- 52 kg of water, - 4.95 kg of latex 1, i.e. 2 kg of polyvinyl chloride, - - 3.15 kg of latex 2, i.e. 1.25 Xg of polyvinyl ~ chloride, -~
- 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 2.7 g of copper sulphate, - 50 kg of vinyl chloride.
Polymerization is carried out in the same way as in example 2.
The latex obtained has a polymer concentxation of 43% by weight. Particle siæe analysis shows it to contain two populations of elementary particles with respective average 3 diameters of 0.88 ~m and 0.C2;~m~ constituting 10 and ~0~/O by ~()8;~4~7 wci~ht Or: the poly~er. This confirms the gro~7th of t~-~e parti-cles oE t:lle 2 seediny latices.
Ex~t~e 16 -- Preparation of seedin~ latex 1 in microsuspension.
_ Preparation is the same as t~lat of latex 1 in example 1.
- Preparation of seedinq latex 2 in emulsion.
The preparation of seeding latex 2 from example 1 is repeated.
- Preparation of seedinq latex 3 in emulsion.
The following are placed in a 120 liter autoclave:
- 65 kg of water, - 2 kg of a 5% by weight aqueous solution of potassium laurate, - 0~$3 kg of ammonia at 22 Baume, - 52 kg of vinyl chloride.
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the operation. As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced. After 9-1/2 hours at 52C, the unreacted vinyl chloride is degassed. The latex obtained has a polymer concentration of 40.2% by weight and a particle diameter of 0.2 ~m. The particles do not contain any initiator.
- Polymerization The following are placed in a 120 liter autoclave:
- 33.2 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of- polyvinyl chlor-ide containing 34.5 g of lauroyl peroxide, 3 - 1.75 kg of latex 2, i.e. 0.7 k-~ of polyvinyl ~ o~
cilioridc, - 1.5 kg of a l~/o by weight aqueous solution of ~odium dodecylkenzene sulphonate, - 55 Xy of vinyl chloride.
The reaction mixture is agitated, at an aqitator speed o 50 revs/min and heated to 52C. After 3 hours, 2.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate is added.
After 18 hours' reaction, a drop in pressure is ob-served. When the pressure has dropped 2 bars, the unreacted vinyl chloride is degassed. The latex obtained has a polymer ;
concentration of 54% by weight and a viscosity of 25 cp.
The weight of crusts in the autoclave is only 300 g.
Particle size analysis of the latex obtained shows the polymer to be made up of three populations of particles, with respective average diameters of 0.16 ~m, 0.40 ~m and 0.97 ~m, constituting respectively 16%, 2~/o and 64% of the weight of polymer.
Comparison between latex of example 16 and latex of example 1 shows that, for a same polymer concentration, the viscosities are different.
Example 17 The seeding latex 1 used is that from example 1.
- Preparation of seedinq latex 2 in emulsion The preparation of seeding latex 3 from example 16 is repeated.
- Preparation of seedinq latex 3 in emulsion This is prepared like the seeding laiex in compara-tive test D of example 2.
lOBZ84!7 - Pol~m_r_ ation The following are placecl in a 120 liter a~ltoclave;
- 33.2 kg of water, - 5.7 ky of latex l, i.e. 2.3 kg o~ polyvinyl chlor-ide containing 34.5 y of lauroyl peroxide, - 10.5 kg of latex 2, i.e. 4.2 kg of polyvinyl chloride, - 10.5 kg of latex 3, i.e. 4.2 kg of polyvinyl chloride, - 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
Polymerization is carried out as in example 16 and the latex obtained has a polymer concentration of 53% by weight and a viscosity of 45 cp.
The weight of crusts in the autoclave is only 320 g.
Particle size analysis shows the latex to contain three populations of elementary particles with respective aver-age diameters of 0.26 ym, 0.54 ~m and 0.92 ~m, constituting 22, 32 and 46% by weight of the polymer.
Example 18 Seeding latices l and 2 from example 16 are used in polymerization.
- Pr~paration of seeding latex 3 in emulsion The preparation of seeding latex 2 from example 1 is repeated, but with 1.04 kg of a 10/~ by weight aqueous solution of sodium tetradecylsulphonate irstead of 2.6 kg and without the introduction of sodium tetradecylsulphonate during poly-merization. The partjcle di~neter of the latex o~tained is 0.031 ~m.
-3~-10~2~
- ~olvmerizd~ n This is done under t~le salne conditions as in excm~ple 16.
The latex obtained has a viscosity of 22 cp and con-tains three populations of particles constituting 13, 22 and 65% by weight of the polymer, with respective average diameters of 0.067 ~m, 0.19 ~m and 0.97 ~m.
Example 19 - PreparatiDn of seedinq latex 1 in microsuspension The preparation of seeding latex 1 from example 1 is repeated.
- Preparation of seedinq latex 2 in emulsion The following are placed in a 25 liter autoclave:
- 9.1 kg of water, - 0.75 ky o~ s~eding latex 3 of example 18, i.e.
0.3 kg of polyvinyl chloride.
These are agitated and heated to 75C, and this tem-perature is maintained throughout the operation. As soon as the mixture is at 75C, 12 g of potassium persulphate in solu-tion in 100 g of water is introduced. 6 kg of butylacrylate and one liter o~ an aqueous solution containing 30 g of sodium pyrophosphate and 60 g of sodium dodecylbenzene sulphonate are then added simultaneously and continuously over three hours.
After 8 hours, the reaction is stopped; the latex obtained has a polymer concentration of 33% by weight and an average particle diameter of 0.09 ~m.
- Polymerization The procedure is as in example-l but using 4.25 kg of latex 2 above, i.e. 1.4 kg of polymer.
3 The lat2x obtained has a concentration of 52% by weight and a viscosity of 4n cp.
-3~-~V~
ïlle ~ieig]lt of C'I.UStS ill ~he au~ociave is only 400 g.
Particle si~e arlal.ysis Oc the latex obtained shows the polyrn~r to be made UE~ of two populatic)ns of par~icLes with re.spective average cliameters of O~].B ~Im and 0.96~um, the fine particles constituting 30% by weight.
3o
The reaction mixture is agitated, heated to 52C
under autogenous pressure and kept at that temperature through-out the reaction.
After 3 hours' reaction, 2.5 kg of a 10% by wei~,ht aqueous solution o sodium dodecylbenzene sulphonate is added to the mixture. The drop in pressure takes place after 12 hours' reaction. When it has dropped 2 bars, the unreacted vinyl chloride is degassed.
The polymer concentration of the latex obtained is 54% by weight. The weight of crusts is 500 g.
The two populations of particles forming the polymer have respective average diameters of 0.18~m and 0.99 ~m which constitute 29 and 71% of the weight.
Example 13 Example 8 is repeated except that the following are used for polymerization:
- 16.4 kg of water, - 52.25 kg of vinyl chloride and - 2.75 kg of vinyl acetate.
The latex obtained has a concentration of 58.1% by weight and a viscosity of 40 cp. The weight of crusts is low, -- ~0--- 108289~7 at 150 g. llle polyrncx ls made up of 22% by weight o~ particles ~it:h an a-~ex.lc3e diameter of O.Z2~m and 78% by wei~ht of parti-Cle9 with an average cliameter of 1.05 ~m.
The latex is atomized; the product obtained is a copolymer containing 3.6% by weight of ~-inyl acetate. The rheological properties of plastisols containing different quancities of dioctyl phthalate are gi~en in table 13.
TABLE l3.
:
: D O P : Brookfield : Severs :
:parts/100 : viscosity :(poises) Speed gradient : Viscosity :of polymer: 1/2 hour : 1 day : (sec~l) : (poises) :
280 660 : 100 ; 700 : : : (390 :(390 :100 :2~0 : : : (940 :(240 :
: : : (1000 : (70 : 60 : 30 35 : : : (2600 (58 A low viscosity plastisol containing 40 parts by ~0 weight of dioctyl phthalate per 100 parts by weight of vinyl chloride/vinyl acetate copolymer is found to be obtained; this is impossible with previous processes.
Example 1-~
- Seeding latex 1 used is that from exarnple 1.
- PreParation of seediny latex 2 in emulsion.
The procedure is eactly the same as in example 1.
The diameter o~ the particles obtained is 0.115 ~m.
- Polymerization'O
Example 2 is repeated.
At the end of the react~oll the concentration of the 1()8*~!7 ]a~ 54.g~0 ~-y w2icJht a~ld its viscosi~y is 40 cp. ~rhe weight of crusts in the autoclave is 150 g.
The polymer o tlle latex is made up of 69~/o by weight of particles with an average diameter of 0.98,um and 31% by weight o~ particles with an average diameter of 0.19 ~m.
Comparative tests E and F in emulsion with two seed-ing latices of the emulsion type.
- Preparation of seeding latex 1 in emulsion.
The procedure is like that followed in preparing the seeding latex in comparative test D of example 2.
- Preparation of seedinq latex 2 in emulsion. `~
e) The preparation of seeding latex 2 from example 1 is repeated, except that 1.04 kg of a 10% by weight aqueous colution of sodium tetradecylsulphonate is used instead of 2.6 ky, and no sodium tetradecylsulphonate is introduced during polymerization. The particle diameter of the latex obtained is 0.031 ~m.
f) The procedure is exactly the same as in e). The particle diameter of the latex obtained is 0.025~um.
Two polymerizations ~re carried out as follows, one with latex 2e and the other with latex 2f. The proportions are such that the weight ratio of the two populations of par-ticles and the diameter of the largest particles in the latex to be obtained are close to those of the latex in example 14.
The following are charged into a 25 liter autoclave:
- 8000 g of deionized water, - seeding latices 1 and 2 in varying quantities - vinyl chloride in a ~antity such that the weight of monomer and seeding polymer is 7000 g.
3 The mixture is agitated and heated to 52C. ~s soon ~0~284 7 as the rnixtllre t'eclC-n~S that temperatu~e, ~ g of ~onium per-sulphate is introduced. One hour la~el^, Z liters of a 1~75'~/o by weight aqueous solution of sodium dodecylbellzcne sulphonate is introduced continuously at a rate of 0.23 liter/hour.
When pressure is at 5 bar~" the unreacted monomer is degassed.
The operating data and results of tests E and F are ~ -summarized in table 14 and compared ~iih examples 2 and 14.
A study of this table shows that a slight difference in the particle diameters of seeding latices Z in polymeriza-tion in microsuspension results in virtually no differences in the particle size of the products obtained or in the rheologi-cal properties. On the other hand, an identical difference between the particle diam~ters of seeding latices 2 in poly-merizatJon in emulslon ~eads to significant differences in the particle size of the products obtained and consequently in their rheological properties. In t'mis case there is no reproducibility of the process.
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2 ~ ~ ~ ~ ~ P.
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108ZB~7 ~
- Pre~ ion of se~dinq l~ta~ 1 in microsuspension.
The preparation of seecling lal:ex 1 from example 1 is repe;lted with homogellization such that ~he average particle diameter of the latex is 0.25 ~m. The polymer concentration of the late~ obtained is 40O/o by wei~ht and the particles con-tain 1.5% by weight, relative to the polymer, of lauroyl per-oxide.
- Preparation of seedinq latex 2 in emulsion.
Procedure is the same as in comparative test D in example 2, but with 0.43 kg, instead of 2.6 kg. of seeding latex 2 from example 1, i.e. 0.190 kg of polyvinyl chloride.
The latex obtained has a polymer concentration of 40/O by weight, and the diameter of its particles is 0.74 ~m.
- PolYm~riY~ation~
The following are placed in a 120 liter autoclave:
- 52 kg of water, - 4.95 kg of latex 1, i.e. 2 kg of polyvinyl chloride, - - 3.15 kg of latex 2, i.e. 1.25 Xg of polyvinyl ~ chloride, -~
- 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 2.7 g of copper sulphate, - 50 kg of vinyl chloride.
Polymerization is carried out in the same way as in example 2.
The latex obtained has a polymer concentxation of 43% by weight. Particle siæe analysis shows it to contain two populations of elementary particles with respective average 3 diameters of 0.88 ~m and 0.C2;~m~ constituting 10 and ~0~/O by ~()8;~4~7 wci~ht Or: the poly~er. This confirms the gro~7th of t~-~e parti-cles oE t:lle 2 seediny latices.
Ex~t~e 16 -- Preparation of seedin~ latex 1 in microsuspension.
_ Preparation is the same as t~lat of latex 1 in example 1.
- Preparation of seedinq latex 2 in emulsion.
The preparation of seeding latex 2 from example 1 is repeated.
- Preparation of seedinq latex 3 in emulsion.
The following are placed in a 120 liter autoclave:
- 65 kg of water, - 2 kg of a 5% by weight aqueous solution of potassium laurate, - 0~$3 kg of ammonia at 22 Baume, - 52 kg of vinyl chloride.
The mixture is then heated to 52C under autogenous pressure and this temperature is maintained throughout the operation. As soon as the mixture is at 52C, 0.035 kg of potassium persulphate is introduced. After 9-1/2 hours at 52C, the unreacted vinyl chloride is degassed. The latex obtained has a polymer concentration of 40.2% by weight and a particle diameter of 0.2 ~m. The particles do not contain any initiator.
- Polymerization The following are placed in a 120 liter autoclave:
- 33.2 kg of water, - 5.7 kg of latex 1, i.e. 2.3 kg of- polyvinyl chlor-ide containing 34.5 g of lauroyl peroxide, 3 - 1.75 kg of latex 2, i.e. 0.7 k-~ of polyvinyl ~ o~
cilioridc, - 1.5 kg of a l~/o by weight aqueous solution of ~odium dodecylkenzene sulphonate, - 55 Xy of vinyl chloride.
The reaction mixture is agitated, at an aqitator speed o 50 revs/min and heated to 52C. After 3 hours, 2.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate is added.
After 18 hours' reaction, a drop in pressure is ob-served. When the pressure has dropped 2 bars, the unreacted vinyl chloride is degassed. The latex obtained has a polymer ;
concentration of 54% by weight and a viscosity of 25 cp.
The weight of crusts in the autoclave is only 300 g.
Particle size analysis of the latex obtained shows the polymer to be made up of three populations of particles, with respective average diameters of 0.16 ~m, 0.40 ~m and 0.97 ~m, constituting respectively 16%, 2~/o and 64% of the weight of polymer.
Comparison between latex of example 16 and latex of example 1 shows that, for a same polymer concentration, the viscosities are different.
Example 17 The seeding latex 1 used is that from example 1.
- Preparation of seedinq latex 2 in emulsion The preparation of seeding latex 3 from example 16 is repeated.
- Preparation of seedinq latex 3 in emulsion This is prepared like the seeding laiex in compara-tive test D of example 2.
lOBZ84!7 - Pol~m_r_ ation The following are placecl in a 120 liter a~ltoclave;
- 33.2 kg of water, - 5.7 ky of latex l, i.e. 2.3 kg o~ polyvinyl chlor-ide containing 34.5 y of lauroyl peroxide, - 10.5 kg of latex 2, i.e. 4.2 kg of polyvinyl chloride, - 10.5 kg of latex 3, i.e. 4.2 kg of polyvinyl chloride, - 1.5 kg of a 10% by weight aqueous solution of sodium dodecylbenzene sulphonate, - 55 kg of vinyl chloride.
Polymerization is carried out as in example 16 and the latex obtained has a polymer concentration of 53% by weight and a viscosity of 45 cp.
The weight of crusts in the autoclave is only 320 g.
Particle size analysis shows the latex to contain three populations of elementary particles with respective aver-age diameters of 0.26 ym, 0.54 ~m and 0.92 ~m, constituting 22, 32 and 46% by weight of the polymer.
Example 18 Seeding latices l and 2 from example 16 are used in polymerization.
- Pr~paration of seeding latex 3 in emulsion The preparation of seeding latex 2 from example 1 is repeated, but with 1.04 kg of a 10/~ by weight aqueous solution of sodium tetradecylsulphonate irstead of 2.6 kg and without the introduction of sodium tetradecylsulphonate during poly-merization. The partjcle di~neter of the latex o~tained is 0.031 ~m.
-3~-10~2~
- ~olvmerizd~ n This is done under t~le salne conditions as in excm~ple 16.
The latex obtained has a viscosity of 22 cp and con-tains three populations of particles constituting 13, 22 and 65% by weight of the polymer, with respective average diameters of 0.067 ~m, 0.19 ~m and 0.97 ~m.
Example 19 - PreparatiDn of seedinq latex 1 in microsuspension The preparation of seeding latex 1 from example 1 is repeated.
- Preparation of seedinq latex 2 in emulsion The following are placed in a 25 liter autoclave:
- 9.1 kg of water, - 0.75 ky o~ s~eding latex 3 of example 18, i.e.
0.3 kg of polyvinyl chloride.
These are agitated and heated to 75C, and this tem-perature is maintained throughout the operation. As soon as the mixture is at 75C, 12 g of potassium persulphate in solu-tion in 100 g of water is introduced. 6 kg of butylacrylate and one liter o~ an aqueous solution containing 30 g of sodium pyrophosphate and 60 g of sodium dodecylbenzene sulphonate are then added simultaneously and continuously over three hours.
After 8 hours, the reaction is stopped; the latex obtained has a polymer concentration of 33% by weight and an average particle diameter of 0.09 ~m.
- Polymerization The procedure is as in example-l but using 4.25 kg of latex 2 above, i.e. 1.4 kg of polymer.
3 The lat2x obtained has a concentration of 52% by weight and a viscosity of 4n cp.
-3~-~V~
ïlle ~ieig]lt of C'I.UStS ill ~he au~ociave is only 400 g.
Particle si~e arlal.ysis Oc the latex obtained shows the polyrn~r to be made UE~ of two populatic)ns of par~icLes with re.spective average cliameters of O~].B ~Im and 0.96~um, the fine particles constituting 30% by weight.
3o
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of preparing a polymer of vinyl chloride which is poly-vinyl chloride or a copolymer containing at least 50% by weight of vinyl chloride and at least one copolymerizable monomer, which method comprises polymerizing the corresponding monomer or monomers in microsuspension, in the presence of a first seeding product in the form of a dispersion of particles of a vinyl polymer previously prepared by polymerization in microsuspension, the particles of which contain at least one initiator soluble in organic material, without any complementary addition of initiator, characterized in that polymerization is carried out in the presence of one or more other seed-ing products in the form of dispersions of particles of vinyl polymer, the sizes of which differ from one another and from the particle size of the first seeding product.
2. The method as claimed in Claim 1, in which the vinyl polymer is selected from the group consisting of homopolymers of vinyl chloride, copoly-mers of vinyl chloride with copolymerizable monomers, homopolymers of copoly-merizable monomers and copolymers of said copolymerizable monomers together.
3. The method as claimed in Claim 1, in which the particles of the seeding product or products other than the first contain at least one initia-tor.
4. The method as claimed in Claim 1, in which the average diameter of the polymer particles of the first seeding product is from 0.05 to 1.5 µm.
5. The method as claimed in Claim 1, in which the average diameter of the polymer particles of the seeding product of products other than the first is from 0.02 to 1.5 µm.
6. The method as claimed in Claim 1, in which the seeding product or products other than the first are prepared by polymerization in microsuspen-sion, in the presence of an initiator soluble in organic material.
7. The method as claimed in Claim 1, in which the seeding product or products other than the first are prepared by polymerization in emulsion, in the presence of a water-soluble initiator.
8. The method as claimed in Claim 1, in which the total quantity of seeding products to be used is such that the quantity of polymers contained therein represents 1 to 50% by weight of the sum of vinyl chloride or mixture of vinyl chloride and copolymerizable monomer to be polymerized plus seeding polymers.
9. The method as claimed in Claim 1, in which the ratio of the first seeding polymer to the other seeding polymers is from 95/5 to 5/95.
10. The method as claimed in Claim 1, in which the concentration of seeding polymers plus the vinyl chloride or mixture of vinyl chloride and copolymerizable monomer is from 20 to 80% by weight of the reaction mixture, allowing for the water content of the seeding products.
11. The method as claimed in Claim 1, in which an anionic emulsifier is added before or during polymerization or both before and during polymer-ization.
12. The method as claimed in Claim 11 in which a non-ionic emulsifier is added with the anionic emulsifier.
13. The method as claimed in Claim 1, in which the polymerization speed is accelerated by activation of the initiator contained in the particles of seeding products, by a metal complex, formed in situ, which is soluble in organic material.
14. Latices prepared according to Claim 1, characterized in that they contain at least two populations of particles with different average diameters.
15. Latices according to Claim 14, characterized in that they contain two populations of particles with respective average diameters from 0.4 to 2.5 µm and from 0.08 to 1 µm, in a diameter ratio from 1 to 20/1 and a weight ratio from 0.1 to 10/1.
16. Latices according to Claim 14, characterized in that they contain three populations of particles with respective average diameters of from 0.4 to 2.5 µm, from 0.15 to 1 µm and from 0.05 to 0.4 pm, the diameter ratios of large particles/medium particles and medium particles/fine particles similar or different ranging from 1 to 20/1, and in weight ratios of large particles/
medium particles and medium particles/fine particles, similar or different, ranging from 0.1 to 20/1.
17. Latices according to Claim 14, characterized in that their polymer concentration is from 20 to 75% by weight.
18. Polymers and copolymers in the form of powders suitable for the preparation of plastisols, separated from the latices prepared according to
14. Latices prepared according to Claim 1, characterized in that they contain at least two populations of particles with different average diameters.
15. Latices according to Claim 14, characterized in that they contain two populations of particles with respective average diameters from 0.4 to 2.5 µm and from 0.08 to 1 µm, in a diameter ratio from 1 to 20/1 and a weight ratio from 0.1 to 10/1.
16. Latices according to Claim 14, characterized in that they contain three populations of particles with respective average diameters of from 0.4 to 2.5 µm, from 0.15 to 1 µm and from 0.05 to 0.4 pm, the diameter ratios of large particles/medium particles and medium particles/fine particles similar or different ranging from 1 to 20/1, and in weight ratios of large particles/
medium particles and medium particles/fine particles, similar or different, ranging from 0.1 to 20/1.
17. Latices according to Claim 14, characterized in that their polymer concentration is from 20 to 75% by weight.
18. Polymers and copolymers in the form of powders suitable for the preparation of plastisols, separated from the latices prepared according to
Claim 14.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7513582A FR2309569A1 (en) | 1975-04-30 | 1975-04-30 | Microsuspension polymerisation of PVC - in presence of previously prepd. latex as mucleating agent |
| FR75.13582 | 1975-04-30 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1082847A true CA1082847A (en) | 1980-07-29 |
Family
ID=9154678
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA251,402A Expired CA1082847A (en) | 1975-04-30 | 1976-04-29 | Method of polymerizing vinyl chloride in seeded microsuspension |
Country Status (9)
| Country | Link |
|---|---|
| BE (1) | BE841267A (en) |
| CA (1) | CA1082847A (en) |
| FI (1) | FI61706C (en) |
| FR (1) | FR2309569A1 (en) |
| IN (1) | IN143835B (en) |
| NO (1) | NO151010C (en) |
| PT (1) | PT65051B (en) |
| RO (1) | RO69894A (en) |
| ZA (1) | ZA762573B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101535943B1 (en) * | 2013-12-09 | 2015-07-10 | 한화케미칼 주식회사 | PVC-based compound composition |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2468619B1 (en) * | 1979-11-06 | 1985-06-21 | Rhone Poulenc Ind | PROCESS FOR THE PREPARATION OF VINYL CHLORIDE HOMO- AND CO-POLYMERS SUITABLE FOR GIVING PLASTISOLS FROM A LATEX CONTAINING TWO PARTICLE POPULATIONS |
| FR2601373B1 (en) * | 1986-07-11 | 1988-10-21 | Atochem | PROCESS FOR THE PREPARATION IN EMULSION OR MICROSUSPENSION OF HOMO- AND COPOLYMERS OF VINYL CHLORIDE |
| FR2607138B1 (en) * | 1986-11-24 | 1990-05-04 | Atochem | PROCESS FOR THE PREPARATION OF VINYL CHLORIDE IN SOMETHING MICROSUSPENSION AND COPOLYMERS |
| EP0810241A1 (en) * | 1996-05-31 | 1997-12-03 | Elf Atochem S.A. | Vinylchloride copolymer latex with bimodal particle size distribution, its preparation process and uses |
| FR2752846B1 (en) * | 1996-08-27 | 1998-10-30 | Atochem Elf Sa | BIPOPULA LATEX BASED ON VINYL CHLORIDE POLYMERS, HAVING A HIGH FINE PARTICLE POPULATION RATE, METHODS OF MAKING SAME AND APPLICATIONS THEREOF |
| FR2752844B1 (en) * | 1996-08-27 | 1998-10-30 | Atochem Elf Sa | BIPOPULA LATEX OF POLYMERS BASED ON VINYL CHLORIDE, ITS METHODS OF OBTAINING AND ITS APPLICATION IN PLASTISOLS WITH IMPROVED RHEOLOGY |
| DE19958820B4 (en) * | 1999-12-07 | 2010-04-01 | Vestolit Gmbh & Co. Kg | Process for the preparation of thermoplastic molding compositions, molding compositions prepared by this process and their use |
| MXPA01008706A (en) | 2000-09-03 | 2004-08-12 | Rohm & Haas | High solids polymeric additive systems: compositions, processes, and products thereof. |
| MXPA01008705A (en) | 2000-09-03 | 2004-08-12 | Rohm & Haas | Multiple polymeric additive systems: compositions, processes, and products thereof. |
| EP1379563A2 (en) * | 2001-01-10 | 2004-01-14 | Solvay (Societe Anonyme) | Method for preparing halogenated polymers and resulting halogenated polymers |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT650198A (en) * | 1961-03-24 | |||
| FR2234321B1 (en) * | 1973-06-08 | 1976-06-11 | Rhone Progil |
-
1975
- 1975-04-30 FR FR7513582A patent/FR2309569A1/en active Granted
-
1976
- 1976-04-27 RO RO7685826A patent/RO69894A/en unknown
- 1976-04-28 IN IN744/CAL/76A patent/IN143835B/en unknown
- 1976-04-28 NO NO761464A patent/NO151010C/en unknown
- 1976-04-28 PT PT65051A patent/PT65051B/en unknown
- 1976-04-29 BE BE166558A patent/BE841267A/en not_active IP Right Cessation
- 1976-04-29 CA CA251,402A patent/CA1082847A/en not_active Expired
- 1976-04-29 ZA ZA762573A patent/ZA762573B/en unknown
- 1976-04-29 FI FI761215A patent/FI61706C/en not_active IP Right Cessation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101535943B1 (en) * | 2013-12-09 | 2015-07-10 | 한화케미칼 주식회사 | PVC-based compound composition |
| US10208197B2 (en) | 2013-12-09 | 2019-02-19 | Hanwha Chemical Corporation | PVC-based compound composition |
Also Published As
| Publication number | Publication date |
|---|---|
| PT65051A (en) | 1976-05-01 |
| NO151010C (en) | 1985-01-23 |
| NO151010B (en) | 1984-10-15 |
| PT65051B (en) | 1977-09-12 |
| BE841267A (en) | 1976-10-29 |
| RO69894A (en) | 1983-02-01 |
| IN143835B (en) | 1978-02-11 |
| FI61706B (en) | 1982-05-31 |
| FI61706C (en) | 1982-09-10 |
| FR2309569A1 (en) | 1976-11-26 |
| FI761215A (en) | 1976-10-31 |
| NO761464L (en) | 1977-02-25 |
| ZA762573B (en) | 1977-05-25 |
| FR2309569B1 (en) | 1979-05-25 |
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