MXPA01005502A

MXPA01005502A - Halogen-containing vinyl polymer resins and processes for the preparation thereof.

Info

Publication number: MXPA01005502A
Application number: MXPA01005502A
Authority: MX
Inventors: Yves Vanderveken
Original assignee: Solvay
Priority date: 1998-12-02
Filing date: 1999-11-30
Publication date: 2002-04-10
Also published as: EP1137692A1; GB2344345A; AU1779100A; CN1334840A; JP2002531616A; GB9826524D0; BR9915884A; WO2000032679A1; CA2353571A1

Abstract

Halogen-containing vinyl polymer resins in the form of co-coagulates of particles of halogen-containing vinyl polymer resins and particles which are chosen from the group of processing aids, stabilisers, plasticizers and/or other polymer resins which particles are substantially homogeneously distributed throughout. These co-coagulates are substantially free of polymer dust and fines and are substantially free from lumping and crusting. These co-coagulates are further "ready-to-use", do not require blending or the addition of further components thereto before being extruded, and present good flowability, thermal stability and extrudability.

Description

VINYL POLYMER RESINS CONTAINING HALOGEN AND PROCESSES FOR THE PREVENTION OF SAME Field of the Invention The present invention relates to halogen-containing vinyl polymer resins and particulates to halogen-containing vinyl polymer resins formed by aqueous emulsion polymerization, to processes for the preparation of said resins by co-coagulation with other emulsions, to the use of said resins for the formation of articles thereof by extrusion and to the extruded articles obtained therefrom.

BACKGROUND OF THE INVENTION Traditionally, halogen-containing vinyl polymer resins formed by aqueous emulsion polymerizations are coagulated to produce larger coagulated polymer particles. The liquid portion of the emulsion is subsequently removed from the coagulated polymer leaving a vinyl polymer resin containing coagulated halogen. Polymer resins formed in this manner include fine and powder particles (particles generally having a size of less than about 45 microns of resin). To produce a polymer blend for extrusion, these subsequently dried halogen-containing vinyl polymer resins are blended in a normal manner with other materials, such as stabilizers, plasticizers, processing aids and other polymers, in a mixing machine (mixer) for form a polymer mixture. This polymer mixture is subsequently extruded into extruded articles. Unfortunately, the presence of fine particles and dust in the polymer resins is at least partially responsible for the formation of "sticky" particles which are the source of some problems that arise when mixing (mixing) and extruding mixtures. of polymer. Due to the tendency of fine and powdered particles to melt faster than larger particles under heat, friction or other, to which they are exposed during mixing, they tend to be "sticky", particularly when using a machine high speed mixer. These "sticky" particles tend to adhere not only to others and to other particles of the resin, but also to the blades of the mixing machine. The adhesion of these fine "sticky" particles and polymer powder to others is problematic since it leads to the formation of lumps, which causes problems in the extrusion feed. The adhesion of these fine "sticky" particles and the polymer powder to the blades of the mixing machine is problematic since they are embedded, which leads to poor mixing and results in a lower quality product being obtained ( polymer mix), unless substantial investments are made and a processing stop time is incurred to clean the incrusted blades. Additionally, the fine and powdered particles of the polymer resins have limited capacities to absorb liquids (such as epoxidized soybean oil and liquid plasticizers), which are adhered to the resin during mixing. This results in a polymer resin poorly stabilized or poorly plasticized. This is particularly problematic when the liquid does not fully penetrate the polymer resin being mixed, such as when the resin is a protective polymer, similar to polyvinylidene chloride (PVDC), which resists such penetration. The addition of solid additives, such as processing aids or other polymers, results in a mixture which is heterogeneous in nature and which is subject to segregation during transport and feeding during extrusion, resulting in a non-uniform feed. inducing variations in back pressure, which is undesirable, particularly when PVDC extrusion is involved. Additionally, during extrusion, the finely stabilized fine particles and powders of the polymer resin tend to segregate in the extrusion feed hopper, resulting in a non-uniform feed inducing variations in back pressure in the extruder. In addition, said fine and powdered particles tend to require longer residence times in the extruder, at which time they are exposed to heat from the extruder, which makes them dark or black. The presence of said dark or black particles in the extruded product is highly undesirable, particularly when the final product is a film.

The proposed solutions to avoid the aforementioned problems have focused mostly on avoiding the formation of "sticky" particles of the polymer resin (and not on preventing the formation of fine and powder polymer particles). In particular, resources have been developed for the incorporation of stabilizers, such as epoxidized soybean oil (ESO), into the polymer resin during the polymerization of the emulsion. However, this solution has not been completely satisfactory to solve the problem since the addition of ESO (even at concentrations as low as 4 parts per thousand) during the polymerization, even in the form of an emulsion, leads to the formation of sediment in the autoclave. Said sediment affects in a detrimental way the process and its products that will later be extruded. It can therefore be appreciated that it would be highly desirable to provide a halogen-containing vinyl polymer resin that is substantially free of fine particles and powders, and in particular, a polymer resin having a thermal stabilizer, such as ESO, incorporated in it.

Therefore, there remains a need to provide a solution to the aforementioned problems by providing a vinyl polymer resin containing halogen, and in particular a polymer resin of vinylidene chloride, which is prepared by polymerization in an aqueous emulsion. , wherein the polymer resin is substantially free of fine particles and polymer powder. Additionally, there remains a need to provide a polymer resin substantially free of fine particles and powder having a thermal stabilizer, such as ESO, incorporated therein, so that the resin has a good thermal stability, flowability and water capacity. extrusion and is less prone to becoming lumps than conventional polymer resins.

SUMMARY OF THE INVENTION It is a main object of the present invention to provide halogen-containing vinyl polymer resins, which have improved thermal stability, flowability and extrudability and which are less prone to become lumps than resins of vinyl polymer containing conventional halogen.

In this regard, it is a further major object to provide, resins having those desired additives, such as processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other polymers, incorporated therein, so that the additives do not they need to be added later, so that the mixing of the resin is avoided and so that a resin is provided that is "ready to be used" (i.e., a resin that can be used directly without the need for any additional treatment). , mixed or other processing). It is a further main object of the present invention to provide polymer resins in the form of a co-coagulate having a substantially homogeneous distribution of the halogen-containing vinyl polymer resin and having the form of those other substances, such as as processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other polymers that are desired to be included therein. It is still a further primary object of the present invention to provide polymer resins of 25 vinyl containing halogen which are substantially free of fine particles and polymer powder. A further main object of the present invention is to provide processes for the preparation of halogen-containing vinyl polymer resins and said co-coagulates. In this regard, it is a further main object of the present invention to provide novel processes to include the desired additives, such as stabilizers, processing aids., plasticizers and other polymers with the resin of polymers without the need of, and eliminating the mixing step. It is still yet another object of the present invention to provide methods and use said halogen-containing vinyl polymer resins and said co-coagulates to form extruded articles. A still further object of the present invention is to provide extruded articles formed of said halogen-containing vinyl polymer resins and said co-coagulates. In accordance with the teachings of the present invention, halogen-containing vinyl polymer resins are disclosed in the form of co-coagulates of halogen-containing vinyl polymer resin particles and particles which are selected from the group of processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other polymer resins. These co-coagulates are substantially free of fine particles and polymer powders and are substantially free of lumps and barks. Likewise, having said additives (i.e., processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other polymer resins which are desired to be included therein), which are desired to be included. With the halogen-containing vinyl polymer resin, these co-coagulates have halogen-containing vinyl polymer resins which are "ready-to-use", do not require mixing or adding additional components thereto before being extruded , and have a good flow capacity, thermal stability and extrusion capacity. As used in the present invention, the term "halogen-containing vinyl polymer" refers to those (homo- and co-) polymers that are formed by the polymerization of halogen-containing vinyl monomers. Said polymers can be obtained by any known means. However, radical polymerization in an aqueous emulsion of the halogen-containing vinyl monomers (either by themselves or forming vinyl homopolymers containing halogen or with other copolymerizable monomers, such as vinyl esters, vinyl ethers, acids) is preferred. acrylics, acrylic esters, acrylic nitriles, acrylic amides, methacrylic acids, methacrylic esters, methacrylic amides, styrene, styrenic derivatives, butadiene, olefins such as ethylene and propylene, itaconic acid and maleic anhydride to form vinyl copolymers containing halogen). Examples of such halogen-containing vinyl polymers are polyvinylidene chloride (PVDC), polyvinyl chloride (PVC) and polyvinylidene fluoride (PVDF). As used in the present invention, the term "halogen-containing vinyl polymer resin" refers to those resins of (homo- and co-) polymers that are formed by the polymerization of halogen-containing vinyl monomers. Said polymer resins can be obtained by any known means. However, it is preferable that the radical polymerization in an aqueous emulsion of the halogen-containing vinyl monomers (either by themselves to form vinyl homopolymers having halogen or with other copolymerizable monomers such as vinyl esters, vinyl ethers, acrylic acids , acrylic esters, acrylic nitriles, acrylic amides, methacrylic acids, methacrylic esters, methacrylic amides, styrene, styrenic derivatives, butadiene, olefins such as ethylene and propylene, itaconic acid and maleic anhydride to form vinyl copolymers containing halogen). Examples of such halogen-containing vinyl polymer resins are polyvinylidene chloride (PVDC), polyvinyl chloride (PVC) and polyvinylidene fluoride (PVDF). The co-coagulates of the present invention, are further characterized in that the particles of vinyl polymer resins containing halogen and the chosen particles (included) from the group of processing aids, stabilizers (such as thermal stabilizers), plasticizers and other polymer resins are substantially evenly distributed through the entire diameter of each individual co-coagulate.

Preferably, the particles of the halogen-containing vinyl polymer resins of the co-coagulates of the present invention are formed from radical polymerization in an aqueous emulsion of at least one vinyl monomer containing halogen and at least another monomer. As used in the present invention, the term "radical polymerization in an aqueous emulsion" is used to describe the radical polymerization reactions which are carried out in an aqueous medium in the presence of emulsifying agents and radical initiators. This definition specifically includes "classical" polymerizations in an aqueous emulsion, in which water-soluble radical initiators are employed, as well as microsuspension polymerization (sometimes referred to as homogeneous aqueous dispersions) in which oil-soluble initiators are employed. Polymerization in this way provides an emulsion of monomer droplets by strong mechanical agitation in the presence of emulsifying agents.

As used in the present invention, the term "aqueous dispersion" (sometimes also referred to as "latex") is used to describe the dispersion of the polymer in water obtained after radical polymerization in an aqueous emulsion. As used in the present invention, the term "vinyl monomer" refers to monomers possessing a terminal olefin unsaturation substituted by at least one other atom.

As used in the present invention, the term "halogen-containing vinyl monomer" refers to those vinyl monomers possessing a terminal olefin unsaturation substituted by at least one halogen atom. Examples of such monomers are vinyl chloride, vinylidene chloride, vinyl bromine, vinyl fluoride, vinylidene fluoride, trifluoroethylene, tetrafluoroethylene, chlorotrifluoroethylene and hexafluoropropylene. Vinylidene chloride (VDC) and vinyl chloride (VC) are preferred. It is further preferred that the particles of the halogen-containing vinyl polymer resins of the co-coagulates of the present invention are vinyl polymer resin resins containing chloride. Examples of such chloride-containing vinyl polymer resins are polyvinyl chloride (PVC) having vinyl chloride monomers, and polyvinylidene chloride (PVDC) having vinylidene chloride monomers. As used in the present invention, the term "chloride-containing vinyl polymer resin" refers to those (homo- and co-) polymer resins that are formed by the polymerization of chloride-containing vinyl monomers. Said polymer resins can be obtained by any known means. However, radical polymerization in the aqueous emulsion of the chloride-containing vinyl monomers (either by themselves to form vinyl homopolymers containing chloride or with other copolymerizable monomers, such as vinyl esters, vinyl ethers, acrylic acids) is preferred. , acrylic esters, acrylic nitriles, acrylic amides, methacrylic acids, methacrylic esters, methacrylic amides, styrene, styrenic derivatives, butadiene, olefins such as ethylene and propylene, itaconic acid and maleic anhydride to form copolymers). Examples of such chloride-containing vinyl polymer resins are polyvinylidene chloride (PVDC) and polyvinyl chloride (PVC).

As used in the present invention, the term "chloride-containing vinyl polymer" refers to those resins of (homo- and co-) polymers that are formed by the polymerization of chloride-containing vinyl monomers. Said polymers can be obtained by any known means. However, radical polymerization in an aqueous emulsion of chloride-containing vinyl monomers (either by themselves to form vinyl homopolymers containing chloride or with other copolymerizable monomers) is preferable., such as vinyl esters, vinyl ethers, acrylic acids, acrylic esters, acrylic nitriles, acrylic amides, methacrylic acids, methacrylic esters, methacrylic amides, styrene, styrenic derivatives, butadiene, olefins such as ethylene and propylene, itaconic acid and maleic anhydride for form copolymers). Examples of such chloride-containing vinyl polymers are polyvinylidene chloride (PVDC) and polyvinyl chloride (PVC). As noted above, the halogen-containing vinyl polymer resin particles of the co-coagulates of the present invention can also be particles of halogen-containing vinyl copolymer resins having vinyl monomers containing halogen and at least another monomer. In this regard it is preferable that the particles of vinyl copolymer copolymer resins containing chlorides are particles of copolymers comprised of vinyl monomers containing chloride and at least one other monomer. Examples of said copolymer particles are particles comprised of vinyl chloride monomers and at least one other monomer and particles comprised of vinylidene chloride monomers and at least one other monomer. As used in the present invention, the term "chloride-containing vinyl monomer" refers to those vinyl monomers that possess a terminal olefin unsaturation substituted by at least one chloride atom. Examples of said monomers are vinylidene chloride (VDC) and vinyl chloride (VC). In this regard, particles of copolymers comprised of two different halogen-containing vinyl monomers, and in particular vinylidene chloride monomers and vinyl chloride monomers, are further preferred. In this regard, in one embodiment, the halogen-containing vinyl copolymer resin of the present invention includes a vinylidene chloride / vinyl chloride resin (VDC / VC). Particularly preferred is the VDC / VC copolymer emulsion resin. Still further preferred in this regard, the copolymer particles comprised of two different halogen-containing vinyl monomers (in particular vinylidene chloride monomers and vinyl chloride monomers) and at least one other monomer. It is particularly preferred that the other monomers are acrylate and / or methacrylate monomers. It is particularly preferred in this respect that the other monomers are glycidyl methacrylate monomers. As used in the present invention, the (meth) acrylate monomers are those monomers having the following general formula: CH2 = CR? R.2 wherein Ri is selected from the group consisting of hydrogen and methyl radical and in the wherein, R 2 is selected from the group consisting of radical -CN and radical -CO-OR 3 in which R 3 is selected from the group consisting of hydrogen, alkyl radicals containing from 1 to 18 carbon atoms, alkoxyalkyl radicals having 1 to 18 carbon atoms; to 10 carbon atoms and radicals -NR4Rs, in which R and R5 are selected from the group consisting of hydrogen and an alkyl radical containing from 1 to 10 carbon atoms. Alternatively, these copolymer resins of the co-coagulates of the present invention are formed by the polymerization in an emulsion of a vinyl monomer containing halogen and a monomer or monomers that do not contain a halogen. In this regard, in one embodiment, the halogen-containing vinyl copolymer resin of the present invention includes a vinylidene chloride / methyl acrylate resin (VDC / MA). Additionally in this regard, in another embodiment, the halogen-containing vinyl copolymer resin of the co-coagulates of the present invention includes a vinylidene chloride / methyl acrylate / glycidyl methacrylate resin (VDC / A / GMA). When said copolymers contain vinylidene chloride, it is preferred that the vinylidene chloride be the greater part of the halogen-containing vinyl monomer. In this regard, it is preferred that the copolymer resin have at least about 50% (w / w) vinylidene chloride. It is further preferred that the polymer resin has at least about 60% (w / w) vinylidene chloride. It is further preferred that the polymer resin has at least 70% (w / w) vinylidene chloride. Additionally in this regard, it is preferred that the copolymer resin have no more than about 95% (w / w) vinylidene chloride. It is further preferred that the polymer resin has no more than about 85% (w / w) vinylidene chloride. It is still further preferred that the polymer resin have no more than about 75% (w / w) vinylidene chloride. Most preferably, the copolymer resin is tenu from about 70% (w / w) to 75% (w / w) of vinylidene chloride, with about 72% (w / w) of vinylidene chloride being especially preferred. . As used in the present invention, the term "most part of the halogen-containing vinyl monomer" refers to the halogen-containing vinyl monomer comprising at least 50% (w / w) of the copolymer resin of vinyl that contains halogen of which it is a part.

In the present invention it is contemplated that, in the co-coagulates thereof, the particles of the halogen-containing vinyl polymer resin will be solid. Preferably, the selected particles (included) of the group of processing aids, stabilizers (such as thermal stabilizers), plasticizers and other polymer resins that can be included in the co-coagulates of the present invention, are also provided in an aqueous emulsion. Although not limited to the present invention, it is contemplated therein that examples of the particles of the processing aids which may be included in the co-coagulates of the present invention include acrylate, methacrylate, stearate, wax and polyolefin particles. . Although not limited to the present invention, it is contemplated therein that examples of stabilizer particles (such as thermal stabilizers) that may be included to be included in co-builders of the present invention include epoxidized soybean oil (ESO). and HCl scavengers (such as hydrotalcite-like compounds).

If desired, the stabilizer which is incorporated in the halogen-containing vinyl polymer resins of the co-coagulates of the present invention may be any conventional stabilizer (or liquid processing aid) which has the ability to coagulate with the vinyl polymer. Emulsions of epoxidized soybean oil (ESO) are particularly preferred in this respect. Preferably, the co-coagulates have at least about 0.5% (w / w) of stabilizer. It is also preferred that the co-coagulates have at least about 2% (w / w) of stabilizer. It is further preferred that the co-coagulates have at least at least 4% (w / w) of stabilizer. It should be noted that in this form, when the stabilizer is an ESO emulsion and when the liquid medium is an aqueous emulsion, the stabilizer is distributed very homogeneously throughout all the individual co-coagulates. We have discovered that in the incorporation of the stabilizer in the resin in this form (as a coagulation aid) it significantly increases the amount of co-coagulates that are formed and that have a diameter of at least about 45 microns. We have further discovered that the use of the stabilizer in this form (as a coagulation aid) significantly reduces the stickiness (of the resin and) of the co-coagulates obtained. Furthermore, we consider that the presence of the emulsifier in it ESO plays a role in the internal lubrication during the extrusion of the co-coagulates of the present invention. Although the present invention is not limited, it is contemplated therein that the examples of the plasticizer particles that will be included in the co-coagulates thereof are selected from the group (included) of sebacate debutil, tributyl citrate of acetyl, adipate dioctyl (DOA), latexes of butadiene-styrene and polycaprolactones, such as e-caprolactones. Although not limited to the present invention, it is contemplated that examples of particles of other polymer resins, which will be included in the co-coagulates of the present invention, are selected (included) from the group of homopolymers and copolymers that they have monomers of vinyl chloride, vinylidene chloride, vinylidene fluoride, ethylene vinyl acetate, and ethylene methyl acrylate. It is contemplated in the present invention, that the selected particles (included) of the group of processing aids, stabilizers (such as thermal stabilizers), plasticizers and other polymer resins of the present invention can be either liquid and / or solid. In another aspect of the present invention, a process for the preparation of the halogen-containing vinyl polymer resin containing co-coagulates of the present invention is described. The process for preparing the co-coagulates of the present invention includes the steps of (co) polymerization, co-coagulation and drying. This process is characterized by the co-coagulation of the halogen-containing vinyl polymer resin and the stabilizer (and, thereby avoiding the need for any mixing thereof). In the (co) polymerization step, at least one halogen-containing vinyl monomer is polymerized, whereby an emulsion having particles of the (co) polymer resin in it is formed.

The step of (co) polymerization of the process of the present invention comprises the (co) polymerization of at least one vinyl monomer containing halogen. It is contemplated in the present invention that said (co) polymerization can be (co) radical polymerization, particularly where the formation of (co) polymer resins having VC and / or VDC monomers and / or VDF is desired. It is further contemplated that the (co) polymerization may be (co) radical polymerization in an aqueous medium, and in particular (co) radical polymerization in an aqueous emulsion, once again in particular where the formation of (co) polymer resins having VC and / or VDC monomers is desired. The present invention is particularly adapted to such "classical" (co) polymerization in an aqueous emulsion which is carried out under such conditions well known to those skilled in the art. Therefore, the (co) polymerization will be carried out with the use of emulsifying agents and water-soluble initiators present in amounts well known to those skilled in the art. Examples of said emulsifying agents are anionic emulsifying agents and nonionic emulsifying agents. Examples of anionic emulsifying agents are sulphonate waxes, alkyl sulfonates, alkyl sulfates, mono- and alkylaryl disulfonates and alkylsulfosuccinates. Examples of nonionic emulsifying agents are alkyl- and alkylarylethoxylate derivatives. Examples of water-soluble initiators are water-soluble peroxides such as persulfates of ammonium alkali metal persulfates, hydrogen peroxides, perborates and t-butyl hydroperoxide used only in association with a reductant. The radical (co) polymerizations in an aqueous emulsion are carried out in autoclaves. The monomers, initiators and an emulsifier are all introduced into the autoclave. The temperature inside the autoclave is subsequently increased and agitation begins. Typical temperatures range from about 30 ° C to about 90 ° C. The (co) polymerization time ranges range from about 5 to about 15 hours. At the end of the (co) polymerization reaction, the gas is removed from the autoclave and the separation begins to remove the individual monomers that may remain. Subsequently the emulsion is transferred to the co-coagulator for co-coagulation.

In the co-coagulation step, the particles of the polymer resin in the emulsion and any other particles in the emulsion are co-coagulated, whereby a co-coagulate having the particles of the polymer resin is formed. The co-coagulation step of the process of the present invention comprises the addition of a salt to the anionic emulsion to cause the co-coagulation of the polymer and the formation of a co-coagulate. In accordance with the teachings of the present invention, the emulsion of the other compound is added to the aqueous emulsion including the polymer resin during co-coagulation simultaneously with the co-coagulation salt. In the drying step, the co-coagulates having the particles of the polymer resin are dried, whereby the co-coats that have dry particles of the halogen-containing vinyl polymer resin are formed. The step of separating the liquid medium from the polymer resin of the process of the present invention comprises the removal of a substantial part of the co-coagulated liquid, whereby the co-coagulate is provided in the form of a powder. Said drying step may include the removal of portions of liquid from the co-liquids having the polymer resin, for example by decanting, filtering, etc., to provide a paste. The drying step may further include drying the pulp to provide the co-coagulates having the polymer resin in the form of a powder. The process of the present invention is characterized in particular by the addition to the emulsion, which has the particles of the vinyl polymer resin containing halogen in it, at least one other emulsion having particles of a selected substance (included) ) of the group of stabilizers, processing aids, plasticizers and other polymers and the co-coagulation of these two emulsions (the emulsion having the particles of the polymer resin and the emulsion having the at least one other emulsion having the particles of the selected substance (included) from the group of stabilizers, processing aids, plasticizers and other polymers). In this mode, a co-coagulation comprised of particles of vinyl polymer resins containing halogen and selected particles (included) from the group of processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other resins is formed. polymer. The emulsions of the processes described above and their contents will vary according to the various co-coagulates that the halogen-containing vinyl polymer resin has, which it is desired to produce from them. In yet another aspect of the present invention, the use of the co-coagulates of the present invention having the halogen-containing polymer resin particles and the chosen particles (included) from the group of processing aids, stabilizers (such as as thermal stabilizers), plasticizers and / or other polymer resins for the formation of extruded articles. The polymer / stabilizer resins of the present invention can be used to form articles. In this regard, it is contemplated that the polymer / stabilizer resin will be extruded in an extruder to form extrudable articles, such as monolayer and multilayer films and sheets. Additionally in this regard, it should be noted that the presence of the emulsifier is considered in it. ESO could play an important role in internal lubrication during extrusion. In yet another aspect of the present invention, extruded articles are described which are formed of the co-coagulates of the present invention which have the particles of halogen-containing polymer resins and the chosen particles (included) of the group of auxiliaries of processing, stabilizers (such as thermal stabilizers), plasticizers and / or other polymer resins. Co-coagulating the emulsion containing the halogen-containing vinyl polymer (before mixing) with the emulsion (s) having either the desired processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other resins of polymer according to the present invention, the co-coagulates of the present invention are formed so that each co-coaqulado is in an intimate mixture of each component (ie, the particles of these various components are distributed in a substantially homogeneous form to through each co-coagulated). Therefore, the co-coagulates of the present invention form a very homogeneous mixture.

In this mode, the stabilizers, such as ESO, which are incorporated therein, act as an internal lubricant which is of particular interest when the resins involved have a poor stability, which is particularly noticeable in the case of protective polymers, such as PVDC. Additionally, with co-coaqulado according to the present invention, the particles of the base emulsions, which usually have a size of less than 0.5 microns, are formed in larger co-quakes. A substantial portion of these co-coagulates have a size greater than about 45 microns, so that the resins comprised of said co-coagulates are substantially free of fine particles in polymer powder. As used in the present invention, the term "emulsion resin" is used to refer to a resin that is obtained from an aqueous emulsion prepared using radical polymerization in an aqueous emulsion. The process of the present invention, above all, has the advantage that the polymerization by itself is not affected (without sediment formation, without problems of residual monomers, etc.) and that the particles of the other components (such as processing aids, stabilizers - and particularly ESO -, plasticizers and / or other polymer resins) are always well incorporated, and therefore well protected. In this respect, we will note that in contrast to the polymerization of the suspension (where it can be placed directly in the polymerization reactor during the polymerization), this is not possible when the polymerization of the emulsion is involved due to the formation of sediment which causes said addition, even when an emulsified ESO is used. Therefore, the process of the present invention provides a form wherein said ESO can be satisfactorily incorporated into the polymer resin. Furthermore, it is considered that the presence of the emulsifier in it ESO plays an important role in the internal lubrication during the extrusion of the co-coagulates of the present invention. Other important characteristics of the co-coagulates, in particular their thermal stability, the protective properties thereof and their extrusion capacity, are at least equivalent or superior to those compared with a premix. In this regard, we have observed that while premixes may tend to not have the extrusion capability due to extensive lump generation, the "ready-to-use" co-coagulants of the present invention provide for the emergence of very stable extrusion conditions .

The halogen-containing polymer resins of the co-coagulates of the present invention can be either homopolymers or copolymers. It is contemplated that the copolymers of the co-coagulates of the present invention may be formed by any copolymerization or by independent polymerization and subsequent mixing. Preferably, these copolymer resins of the co-coagulates of the present invention are formed by the polymerization in the emulsion of at least two different halogen-containing vinyl monomers. The above-described properties of the co-coagulates of the present invention, and particularly the properties of the increased particle size and reduced stickiness, which are obtained by the process of the present invention, allow the co-coagulates to have the resin. polymer stabilizer that will be used without any mixing. Additionally, the co-coagulates of the present invention are less prone to both embedding in the blades of the mixing machine and generating clods (the formation of less and / or smaller lumps). In this mode, the co-coagulates of the present invention exhibit good flowability, thermal stability and extrudability. Having thus described the present invention, examples are presented below for illustrative purposes only, which does not mean a limit to the scope of the present invention. Example Polymerization In a 16 liter autoclave, 6150 cm3 of demineralized water was introduced. Subsequently, under agitation at 160 rpm using a propellant, 390 cm3 of a solution of 110 g / I of tetrapropylbenzene sulfonate, 4590 g of VDC monomer and 1910 g of VC monomer were added and the temperature of the autoclave was adjusted to 46 ° C. . At a temperature of 44 ° C, 110 cm 3 of an aqueous solution of 20 g / l of erythorbic acid was added to the solution in the autoclave, followed by the successive addition of 100 cm 3 of an aqueous solution of 3.5 g / l H 2 O 2. 30 minutes later, an aqueous solution (3 g / I) of erythorbic acid and an aqueous solution of 0.8 g / l H202 were injected continuously (in respective ranges of 100 cm 3 / hours) for about 450 minutes. After depressurizing the autoclave for about 3 hours, the autoclave was cooled to room temperature. Subsequently, 2500 cm3 of demineralized water was added to dilute the latex with VDC base. Co-coagulation according to the present invention In a first 150 liter tub, regulated by a water casing, 30 liters of demineralized water and 0.7 liters of an aqueous solution of aluminum sulphate (8.6 g / I) were added. Subsequently, the tub was placed under agitation at 200 rpm and the temperature thereof was adjusted to approximately 15 ° C. Subsequently, 23 liters of the VDC latex formed together with 1 liter of an emulsion of epoxidized soybean oil (at about 250 g / I) were added in a uniform and continuous manner in parallel to the first tank for approximately 20 minutes.

Subsequently, the first tank was heated to a temperature of 70 ° C and maintained at said temperature for 90 minutes. Subsequently, the tub was cooled to room temperature, producing a paste that has the co-coagulated in it. Coagulation through a classical medium (for comparison) A 30 liter demineralized water and 0.7 liter aqueous aluminum sulphate solution (8.6 g / l) were added in a second 150 liter tank, regulated by a water jacket. . Subsequently a second tank was placed under agitation at 200 rpm and the temperature thereof was adjusted to approximately 15 ° C. Subsequently, 23 liters of formed VDC latex were added in a uniform and continuous manner parallel to the second tank for approximately 20 minutes. Subsequently the second tank was heated to a temperature of 70 ° C and maintained at said temperature for 90 minutes. Later the second tub was cooled to room temperature, producing a paste that has a conventional coagulate.

Drying The pulps from the first and second vats were subsequently dried, separating the liquid from the solid first in an ESCHER WYSS® system. In this mode, a "paste" was formed of the co-coagulates of the present invention (from tub 1) and a "paste" having traditional coagulates (from tub 2). Subsequently, the pulps were dried in a Munster® fuidized bed at an inlet air temperature of approximately 60 ° C until the content of volatile material in it was reduced to less than 0.3% (w / w). The particle sizes of the co-coagulated particles of the two pastes were subsequently measured and the results are provided later in Table 1. Table 1

Claims

NOVELTY OF THE INVENTION Having described the present invention, and therefore, it is claimed as property that contained in the following: CLAIMS 1.- A vinylidene chloride polymer resin characterized in that the resin is free of fine particles and dust. the polymer resin and because the resin is comprised of co-coagulated particles of vinylidene chloride polymer resins and particles chosen from the group consisting of processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other resins of polymer.
2. The polymer resin of vinylidene chloride according to claim 1, further characterized in that the particles of the vinylidene chloride polymer resins and the particles chosen from the group consisting of processing aids, stabilizers (such as thermal stabilizers), plasticizers and / or other co-coagulated polymer resins are distributed homogeneously throughout the diameter of each co-coagulate.
3. - The vinylidene chloride polymer resin according to any of claims 1 to 2, further characterized in that the particles of vinylidene chloride polymer resins are particles of copolymers of vinylidene chloride monomers and by at least another monomer.
4. The polymer resin of vinylidene chloride according to claim 3, further characterized in that the particles of the vinylidene chloride polymer resins are particles of copolymers of vinylidene chloride monomers and vinyl chloride monomers.
5. The vinylidene chloride polymer resin according to claim 3, further characterized in that the particles of the vinylidene chloride polymer resins are particles of copolymers of vinylidene chloride monomers and acrylate or methacrylate monomers.
6. The vinylidene chloride polymer resin according to claim 5, further characterized in that the particles of the vinylidene chloride polymer resins are particles of copolymers of vinylidene chloride monomers and q-cycidyl methacrylate monomers.
7. - The polymer resin of vinylidene chloride according to any of claims 1 to 6, further characterized in that the particles of stabilizers are epoxidized soybean oil (ESO).
8. A process for the preparation of a polymer resin of vinylidene chloride free of fine particles and powder of the polymer resin that includes the polymerization steps of a vinylidene chloride monomer, whereby an emulsion is formed having the polymer, coagulation of the emulsion polymer, whereby a coagulated polymer is formed and the coagulated polymer is dried, whereby a dry vinylidene chloride polymer resin is formed, the process being characterized by addition to the polymer. emulsion having the polymer of an emulsion which includes a substance selected from a group of stabilizers, processing aids, plasticizers and other polymers and the co-coagulation of the emulsion having the polymer and the emulsion having the substance, so that a co-coked polymer resin is formed.
9. The process according to claim 8, further characterized in that the stabilizer added to the polymer resin and co-coagulated therein is epoxidized soybean oil (ESO).
10. The process according to any of claims 8 to 9, further characterized by the copolymerization of a vinylidene chloride monomer and another monomer, whereby an emulsion having a chloride-containing copolymer is formed of vinylidene.
11. The use of polymer resins containing vinylidene chloride of any of claims 1 to 7, for the formation of articles that can be extruded.
12.- Characterized extruded articles, being formed of the polymer resins containing vinylidene chloride of any of claims 1 to 7.