MXPA99011160A - Coated calcium or magnesium acetylacetonate, and its use for stabilising halogenated polymers - Google Patents

Abstract

The invention concerns a compound containing calcium or magnesium acetylacetonate, at least partially coated with a compatible agent selected among alcohol's, carboxylic or sulphonic acids, or their derivatives, phosphates or titanates,&bgr;-ketone compounds;said agents having at least a long chain radical;waxes;polyols;epoxydized vegetable oils;polysiloxane oils or resins or silanes. The invention also concerns the preparation of such a compound and the use of said compound as additive in formulations based on halogenated polymers.

Description

CALCIUM OR MAGNESIUM ACETYLACETONATE AND ITS USE AS A STABILIZER OF HALOGENATED POLYMERS The present invention relates to a composition comprising calcium or magnesium acetylacetonate at least partially coated with a compatibilizing agent, and its production. It also relates to the use of the compound as an additive in formulations based on halogenated polymers. Calcium acetylacetonate is one of best known thermal stabilizers for formulations comprising halogenated polymers, and more particularly polyvinyl chloride. However, although it has been established without a doubt that the halogenated polymer formulations can be effectively stabilized with respect to temperature, the use of said stabilized polymers presents some problems, it has been demonstrated that the presence of just that chelate is the cause of the defects of the polymer formed. More particularly, it has been noted that heterogeneities appear in articles obtained in the form of dimples, grains or even pitting. One of the aims of the present invention is, therefore, to propose a solution to the problems of the heterogeneities that appear in shaping formulations based on halogenated polymers and stabilized with calcium or magnesium acetylacetonate. It has been unexpectedly discovered that an association of calcium or magnesium acetylacetonate with a particular compound that coats at least a portion of the chelate can eliminate the aforementioned problems with the heterogeneities of the polymeric formulation. In this regard, the compound that at least partially coats the chelate can revert to the calcium or magnesium acetylacetonate compatible with the formulation. It should be mentioned that the coating can also act in such a way that it reverts to water-repellent calcium or magnesium acetylacetonate, reducing or even eliminating the moisture absorption of these compounds. In this way, and as a result, the service properties of the final polymeric formulation, for example, resistance to welding, improve. Finally, the coating can improve the dispersion in the calcium or magnesium acetylacetonate in the formulation comprising the halogenated polymer. Thus, in a first aspect, the present invention is constituted by a compound comprising calcium or magnesium acetylacetonate partially or completely coated with at least one compatibilizing agent selected from: • alcohols containing from 12 to 30 carbon atoms, which they can be saturated or unsaturated; • carboxylic or sulphonic acids containing from 12 to 30 carbon atoms, which can be saturated or unsaturated, substituted or unsubstituted with at least one hydroxyl group, or derivatives thereof; • phosphates or titanates comprising at least one chain containing 12 to 30 carbon atoms, which may be saturated or unsaturated; • ß-diketone compounds with at least one chain containing at least 7 carbon atoms; • waxes, - epoxidized vegetable oils; • polysiloxane oils or resins or silanes. In a second aspect, the invention is constituted by a process for preparing the above additive, wherein the magnesium or calcium acetylacetonate is contacted with at least one compatibilizing agent, optionally in the form of a suspension or a dispersion. The present invention also relates to the use of the compound as an additive in formulation comprising at least one halogenated polymer. Other features and advantages of the present invention will become clear from the following description. The metal acetylacetonate used in that of the present invention corresponds to the following formula [CH3COCHCOCH3 2M, xH20, where x is in the range of 0 and 2 and M represents calcium or magnesium. The present invention is particularly suitable for calcium acetylacetonate. Calcium acetylacetonate is well known and has great availability, for example, in Rhodia CEIME under the trade name Rhodiastab®. For the sake of simplicity, the rest of the presentation will refer only to acetylacetonate, it being understood that this term covers both calcium acetylacetonate and magnesium acetylacetonate. The scope of the present invention also encompasses the use of a combination of both acetylacetonates. Acetylacetonate is generally used in the form of powder whose grain size is in the range of 3 to 200 μm. In accordance with one of the essential features of the present invention, the acetylacetonate is partially or completely coated with at least one compatibilizing agent. More particularly, this compatibilized agent is selected from: • alcohols containing from 12 to 30 carbon atoms, which may be saturated or unsaturated; • carboxylic or sulphonic acids containing from 12 to 30 carbon atoms, which can be saturated or unsaturated, substituted or unsubstituted with at least one hydroxyl group, or derivatives thereof; • phosphates or titanates comprising at least one chain containing 12 to 30 carbon atoms7 which can be saturated or unsaturated; • composed of ß-diketones with at least one chain containing at least 7 carbon atoms; • waxes; • epoxidized vegetable oils; • polysiloxane oils or resins or silanes. "With regard to alcohols containing de_12 a carbon atoms, saturated or unsaturated aliphatic monoalcohols are particularly suitable. Among the non-limiting examples that may be cited are lauric, myristic, isostearic, cetyl, behenic, lauroleic, erucic and linoleic alcohol, used alone or as a mixture. The compatibilizing agents that can be used in the present invention include carboxylic acids containing from 12 to 30 carbon atoms, if as derivatives thereof.

More particularly, the compatibilizing agent may be a linear or branched carboxylic acid containing from 12 to 30 carbon atoms, which may be saturated or unsaturated, further comprising one or more hydroxyl groups. Agents of this type which may be mentioned are stearic, lauric, myristic, palmitic, oleic, ricinoleic, behenic (docosanoic), linoleic, hydroxystearic, or any other acid originating from glycerides or triglycerides, natural or another type, suitable for carrying out the invention. The acids can be used alone or as a mixture. With respect to possible derivatives of these acids, there may be mentioned the esters of these acids, in particular esters obtained from monoalcohols containing from 1 to 30 carbon atoms, or mono- or polyesters obtained from polyols, for example, the glycerol derivatives , or alkylene glycols, such as propylene glycol. The salts of the carboxylic acids mentioned above constitute an additional class of derivatives of these acids. The salts of the alkali metals, rare earth metals, aluminum, lanthanum and zinc are particularly suitable. More particularly sodium, calcium, magnesium, aluminum, lanthanum or zinc salts are used. A suitable sulfonic acid which can be cited is docecylbenzensulfonic acid. Among the compatibilizing agents that can be used in the context of the present invention, the ß-diketones with the formula R 1 COCHR 2 COR 3 stand out; where the radical Rx represents a linear C7-C30 hydrocarbon radical branched, substituted or unsubstituted, the radical R3 represents a linear or branched, substituted or unsubstituted C- ^ - CjQ hydrocarbon radical and R2 is a hydrogen atom or a hydrocarbon radical Cx- C4 linear or branched. More particularly, the radical R1 represents a linear or branched C7-C30 alkyl or alkenyl radical; the radical R3 represents a C 1 -C 30 alkyl or alkenyl radical; a C 1 -C 30 aryl radical, substituted or unsubstituted by at least one alkyl radical or a halogen atom or a silicone atom, or all of these; or a C3-C14 cycloaliphatic radical optionally containing carbon-carbon double bonds. It should be mentioned that the radicals R1 and R3 can be identical or different. Preferably, the radical R3 represents a linear or branched alkyl d-Cj ^ radical; a C6 ~ C10 aryl radical substituted or unsubstituted by "at least one alkyl radical or one halogen atom, or both, or a C3-C14 cycloaliphatic radical which may, if desired, contain carbon-carbon double bonds. - The above-described "radicals" R1 and R3 can optionally be modified (substituted) with the presence of an aliphatic chain in one or more groups of formula -0-, - CO- 0-, -C0-. be a hydrogen atom or an alkyl radical .C -.- ^ whose aliphatic chain can be interrupted (replaced) with one or more groups of formula -OR-, -CO-O-, -CO-. Preferably R2 represents a hydrogen atom. Among the ß-diketones that may be mentioned are octanoylbenzoylmethane, stearoylbenzoylmethane, palmitoylbenzoylmethane, laurylbenzoylmethane. Waxes that can be used as a compatibilizing agent of acetylacetonate include montanate waxes, polyethylene waxes or their oxidized derivatives and paraffins. Another compatibilizing agent is constituted by the polyols close to the hydroxyl groups (in the a or β position) or otherwise. These compounds can be used alone or as a mixture. More particularly, polyols containing from 2 to 32 carbon atoms, which carry from two to nine hydroxyl groups, and wherein the hydroxyl groups may be in the near position or not may be used. The compounds include C2-C32 diols, for example propylene glycol, butanediol, hexanediol, dodecanediol, neopentyl glycol, polyols, for example, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, xylitol, mannitol, sorbitol and glycerol, and mixtures of glycerol oligomers. with a degree of polymerization of 2 to 10, hydroxystearic alcohol or ricinoleyl alcohol. An additional family of polyols that can be easily used are polyvinyl alcohols which may be partially acetylated. It is also possible to use hydroxy compounds comprising isocyanurate groups, for example, tris (2-hydroxyethyl) isocyanurate. In a further possibility, the compatibilizing agent is selected from epoxidized vegetable oils, for example, soybean oil or epoxidized castor oil. An additional type of compatibilizing agent may be selected among polysiloxane oils or resins. More particularly, polydialkylsiloxane oils or polyhydroalkylsiloxane oils can be mentioned in cases where the alkyl radical contains from 1 to 3 carbon atoms, preferably a methyl radical. These oils have the following general formula: YO- [(R) Si (R) -O] XY, wherein the radicals R, which may be identical or different, represent an alkyl radical containing from 1 to 3 carbon atoms, preferably a methyl radical, or an atom of hydrogen, provided that one of the two radicals is a hydrogen atom, and represents a hydrogen atom or (R ') 3Si in which the radicals R', which may be identical or different, represent an alkyl radical containing from 1 to 3 carbon atoms, preferably methyl. The coefficient x can vary within a wide range, but more particularly it is in the range of 5 to 300. Also functionalized polymethylsiloxane oils are suitable, for example, Y-hydroxypropylene oils. Finally, with respect to polysiloxane resins, resins obtained by the action of polyhydrogensiloxane oils are more particularly used on polysiloxane oils that transport vinyl groups in the presence of a platinum-based catalyst. It is also possible to use the polysiloxane resins obtained by the hydrolysis and self-condensation of at least one silane of the formula (R0) 3SiF or (R0) 2 (Me) SiF where R, which may be identical or different, "represents a radical alkyl containing 1 to 4 carbon atoms, more particularly, F represents the following radicals: -CH = CH2; - (CH2) 3OH; - (CH2) 3-NH- (CH2) 3NH2CH2CH2NH2; - (CH2) 3? CH2CHCH2; \ / 0 - (CH2) 3OCO-CH = CH2 - (CH2) 3? CO- (CH3) CH = CH2 It is also possible to use the aforementioned silanes as compatibilizing agents In accordance with the present invention, the compatibilizing agent can be used alone or in the form of any mixture of a variety of possible agents cited above In this case, two alternatives are possible: either coating with acetylacetonate the particles comprising a variety of agents, or a mixture of particles, each comprising a coating based on a single agent. The weight ratio of the compatibilizing agent to the acetylacetonate (ie, the calcium acetylacetonate or the magnesium acetylacetonate) can fall within a wide range which may be between 0.1% and 20% by weight with respect to the weight of the acetylacetonate. More particularly, the proportion of the compatibilizing agent is in the range of 0.1% to 10% by weight with respect to the weight of the acetylacetonate. Preferably, the ratio is in the range of 0.1% to 5% by weight with respect to the reference, and more advantageously in the range of 0.1% to 2% by weight with respect to the reference. Now a process for making the additive of the invention will be described. Thus, the compound of the invention can be obtained by contacting calcium or magnesium acetylacetonate with at least one compatibilizing agent, optionally in the presence of a solvent or a dispersing agent, or both. It should be mentioned that the solvent or the dispersing agent, or both, do not dissolve calcium or magnesium acetylacetonate. Generally, the solvent or dispersing agent for the compatibilizing agent, if said solvent or dispersing agent is present, is selected from C1-C5 monoalcohols water, in particular methanol or ethanol, C2-C6 ethers co or dimethyl ether, methylethylether, diethylether and hydrocarbons, for example, hexane. The mixtures of these solvents / dispersing agents are of course possible. In a first variation, which may be referred to as dry impregnation, the amount of solvent / dispersing agent is such that the limit of the absorption capacity of calcium or magnesium acetylacetonate is not exceeded. The person skilled in the art will be able to easily determine the optimum amount of solvent / dispersing agent for the operating conditions (amount, grain size, suspension of the acetylacetonate, amount of the compatibilizing agent). In a further implementation of this variation, the compatibilizing agent is contacted with the acetylacetonate in the absence of a solvent or dispersing agent. The contact with acetylacetonate, in one or other implementation indicated above (presence or absence of solvent / dispersing agent) occurs preferably to control, preferably to avoid any agglomeration of the particles between them. As a result, in the first variation, it is preferable to introduce the compatibilizing agent into the acetylacetonate. This contact can be achieved by using a burette or any similar introduction mechanism. It can also be achieved by using a sprayer fitted with a nozzle. The contact obviously takes place with the agitation, whether caused by mechanical agitation or by the use of a rotating drum or a granulator. The period of operation depends on many criteria. In general, however, it lasts until a microscopically homogenous mixture is obtained, in other words, a free mixture of visible aggregates. In a second variation, the amount of solvent used is such that it dissolves the desired amount of the compatibilizing agent. In this case, again, the person skilled in the art will be able to determine this amount by applying his general knowledge. In this second variation, the dispersions of acetylacetonate in a solution of compatibilizing agent (s) are conventionally obtained. It should be mentioned that a fraction of the compatibilizing agent can always be in the form of a dispersion. In this variation contact can occur by introducing the acetylacetonate into the solution or vice versa, or even by putting both in contact simultaneously. This contact takes place with mechanical agitation, complemented, if necessary, by the application of ultrasound. Whatever the variation used, contact - preferably takes place at room temperature, although higher temperatures are not excluded. The contact operation is advantageously performed in the presence of air. In general, when the acetylaceokethane and the compatibilizing agent have been contacted, drying is effected.Drying may take place at room temperature, by baking or by evaporation of the solvent / dispersing agent, if present, under vacuum. or otherwise, preferably, and this is particularly applicable in the second variation, the drying is carried out in such a way as to avoid too rapid a loss of the solvent / dispersing agent, which could cause agglomeration of the particles. the drying operation is usually in the range of a few minutes to about 12 hours Optionally, and if necessary, before introducing it into the polymer formulation, the coated product can be ground slightly - to deagglomerate the particles. It is evident that this process-- is provided only as a cue and that any other method for coating a product can be applied. Thus, as indicated above, the additive of the invention is more particularly intended for use in formulations containing halogenated polymers. More particularly, the polymers in question are chlorinated polymers. The invention is particularly suitable for stabilizing formulations based on polyvinyl chloride (PVC). The term "polyvinyl chloride" means compositions whose polymer is a vinyl chloride homopolymer The homopolymer can be chemically modified through, for example, chlorination Many vinyl chloride polymers can also be stabilized using the composition in accordance with These are, in particular, polymers obtained by the copolymerization of vinyl chloride with monomers having a polymerizable ethylene glycol bond, for example, vinyl acetate, vinylidene chloride; maleic acid, fumaric acid or esters of these; olefins, for example, ethylene, propylene and hexene; acrylic or methacrylic esters; styrene; vinyl ethers, for example, vinyldodecylether. In general, the polymers contain at least 50% by weight of vinyl chloride units, and preferably at least 80% by weight of said units. PVC, alone or in a mixture with other polymers, is the chlorinated polymer that is used most widely in the stabilized formulations according to the invention. In general terms, any type of polyvinyl chloride is suitable, regardless of its mode of preparation. Accordingly, the polymers obtained, for example, by the use of bulk, suspension or emulsion processes can be stabilized using the composition according to the invention, regardless of the intrinsic viscosity of the polymer. The presence of the additive of the invention in the formulation can improve the compatibility of the acetylacetonate of said polymer formulations, to avoid the problems of heterogeneity caused by the presence of the acetylacetonate alone, when using the formulation. The dispersion of the acetylacetonate in the formulation can also be improved. The amount of the additive of the invention, expressed in magnesium or calcium acetylacetonate is 0.01 to 5 g per 100 grams of halogenated polymer, more particularly 0.05 to 2 g in relation to the same reference. - The polymer formulations can also comprise the usual additives used in the field. Thus, the formulation can comprise at least one β-diketone, which can alternatively be in free form, in the form of a metal chelate or in the form of a mixture of these two species. Therefore, when the β-diketone is in free form it corresponds to the formula (I) R 1 COCHR 2 COR 3, wherein R 1 and R 3, which may be identical or different, each represent a substituted linear or branched C 1 -C 30 hydrocarbon radical. or not substituted, and R2 is an atom of lf hydrogen or a linear or branched C1-C4 linear hydrocarbon radical. When ß-diketone is in the form of a metal chelate, it can be represented by the formula (II) formula II wherein Mn + represents at least one of the following metals: calcium, zinc, aluminum, magnesium or lanthanum being m 2 or 3, R1 and R3 which are identical or different, represents a substituted or unsubstituted linear or branched hydrocarbon radical and dC ^ represents a hydrogen atom of a linear or branched Cx-C4 hydrocarbon radical, with the exception of calcium and magnesium acetylacetonates. Er? In a more specific embodiment of the invention, the radicals R1 and R3, which may be identical or different, represent a linear or branched d-C ^ alkyl or alkenyl radical; a C6-C30 aryl radical substituted or not substituted by at least one alkyl radical or a halogen atom or a silicone atom, or all of these; or a C3-C14 cycloaliphatic radical that can, if desired; contain carbon-carbon double bonds. It should be mentioned that if the ß-diketone compound is present in the two forms mentioned above, the radicals R1 and R3 may differ from one product to another. Preferably, the radicals R 1 and R 3, which may be identical or different, represent a linear or branched C 1 -C 8 alkyl radical; a C6-C10 aryl radical substituted or unsubstituted by at least one alkyl radical or a halogen atom, or both, - or a C3-C14 cycloaliphatic radical which may, if desired, contain carbon-carbon double bonds. In a further variation, the radicals R1 and R3 can be linked together, such that the ß-diketone compound is in the form of a ring. The above-described radicals R1 and R3 can optionally be modified (substituted) in the presence of an aliphatic chain in one or more groups of the formula -0 -, - CO-0 -, - CO-. The radical R2 which can be a hydrogen atom or a C 1 -C 4 alkyl radical whose aliphatic chain can be interrupted (substituted) with one or more groups of formula -O-, -CO-O-, -CO-. Preferably R2 represents a hydrogen atom. The ß-diketones can be obtained according to conventional methods. By way of example, the ß-diketones can be synthesized using a condensation reaction of an ester with a ketone in the presence of an alkaline metal agent which can be an amide of a cation such as sodium, or hydrogen. This reaction has been described in particular in the following publications: R. HAUSER et al., The acylation of ketones to form diketones. "Organic Reactions - Vol. VII, Chapter 3, pp, 59-196, John WILEY, Ed., New York (1954), WIEDMAN et al., CR 238 (1954), pp. 699, MORGAN et al., BER 58 (1925), pp. 333, LIVINGSTONE et al., Am. Soc. 46 (1924) , pp. 881-888, R. LEVINE et al., Am. Soc. 67 (1945), pp. 1510-1517, and in the European patent EP-A-0 596 809. They are non-limiting examples of ß-compounds -dicetone suitable for practicing the invention, mention may be made of octanoylbenzoylmethane, stearoylbenzoylmethane, dibenzoylmethane or acetylbenzoylmethane, alone or as a mixture.It should be noted that it is possible to use purified or unpurified products.The following commercially available products can be used advantageously in the invention: Rhodiastab 50®, Rhodiastab X5®, Rhodiastab X2®, Rodiastab 83®, sold by Rhodia Chimie. these in the form of chelates are also known products and can be obtained by reacting the ß-diketone in question with the aforementioned salts, for example, chlorides, sulfates or nitrates, oxides or hydroxides, with the metal itself, with carbonates or with alcoholates. It should be noted that these methods have been described in xxMetaI ß-diketonates and allied derivatives "by R. Mehrota, R. Gaur, D. P. Gaur, published in 1978 (Academic Press). The chelates of octanoylbenzoylmethane, stearoylbenzoylmethane, palmitoylbenzoylmethane, laurylbenzoylmethane, dibenzoylmethane, acetylbenzoylmethane or otherwise acetylacetone (with the exception of calcium and magnesium acetylacetonates) can advantageously be used alone in a mixture. The total content of ß-diketone, in free or "chelated" form, or both, is in the range of 0.05 to: 1 g per 100 grams of halogenated polymer.

Preferably, the ß-diketone content is in the range of 0.1 to 0.5 g per 100 grams of halogenated polymer. The formulations based on a halogenated polymer may comprise at least one hydrochloric acid scavenger compound. The hydrochloric acid scavenging compounds may be of the organic or inorganic type, and may be present alone or in mixtures. More particularly, among the organic-type hydrochloric acid scrubbers are the compounds comprising an alkaline earth metal or a metal selected in columns IIB, IIA and IVB of the periodic table of the elements (from the "Bulletin de la Société" supplement). Chimique de France '', No. 1 January 1966). More particularly, the cations are preferably selected from calcium, barium, magnesium, strontium, zinc, cadmium, tin and lead. It should be mentioned that it is possible to consider the use of combinations, for example, a mixture of hydrochloric acid scrubber with calcium and zinc base, in barium and zinc, or in barium and cadmium, the first combination being preferred. As regards hydrochloric acid scavenger compounds of the organic type comprising at least one of the elements of columns IIB and IIA, there may be mentioned salts of organic acids, for example, aliphatic or aromatic carboxylic acids or acids fatty acids, or aromatic phenolates or alcoholates. The most commonly used are, for example, the salts of the elements of IIA or IIB of the maleic, acetic, diacetic, propionic, exanoic, 2-ethylhexanoic, decanoic, undecanoic, lauric, myristic, palmitic, stearic, oleic, ricinoleic, behenic (docosanoic), hydroxystearic, hydroxyundecanoic, benzoic, phenylacetic, para-tert-butylbenzoic and salicylic, phenolates, alcoholates derived from naphthol or from phenols substituted with one or more alkyl radicals, for example, nonylphenols. For practical or economic reasons, it is preferred to select, among the abovementioned alkali earth metal organic compounds, alkaline earth metal propionate, earthy alkali metal oleate, earthy alkali metal stearate, alkali earth metal laurate, earth metal ricinolate alkaline, alkaline earthy metal docosanoate, alkali earthy metal benzoate, earthy alkaline earth metal paratert-butylbenzoate, alkaline earthy metal salicylate, earthy alkali metal maleate and earthy alkali metal mono- (2-ethylhexyl) maleate, metal nonylphenate earthy alkaline and alkaline earth metal naphthenate and, among the aforementioned cadmium organic compounds, cadmium propionate, cadmium 2-ethylhexanoate, cadmium laurate, cadmium stearate, cadmium salicylate, mono (2-ethylhexyl) maleate of cadmium, cadmium nonylphenates and cadmium naphthenate. As regards the compounds of the organic type containing lead, those described in ENCYCLOPEDIA of PVC "by Leonard I. NASS (1976), pages 299-303 can be quoted, these are made up of very diverse compounds, of which the most commonly used are dibasic lead carbonate, tribasic lead sulfate. tetrabasic lead sulfate, dibasic lead phosphite, lead orthosilicate, basic lead silicate, coprecipitate of silicate and lead sulfate, basic lead chlorosilicate, coprecipitate of silica gel and lead orthosilicate, lead phthalate dibasic, neutral lead stearate, dibasic lead stearate, tetrabasic lead fumarate, dibasic lead maleate, lead 2-ethylhexanoate and lead laurate. As regards tin-based compounds, reference should be made to the work PLASTICS ADDITIVES HANDBOOK "by GACHTER / MÜLLER (1985), pages 204-210, or in ENCYCLOPEDIA of PVC by Leonard I. NASS (1976), pages 313 More particularly, they are mono- or dialkyltincarboxylates and mono- or dialkylmercaptides, among which the most commonly used compounds are di-n-methyltin derivatives., di-n-butyltin or di-n-octyltin, for example, dibutyltin dilaurate, dibutyltin maleate, dibutyltin laureate-maleate, dibutyltin bis (mono-C4-C8-alkylmaleate), bis (lauryl-mercaptide) dibutyltin, S, S '- (isooctyl mercaptoacetate) dibutyltin, dibutyltin ß-mercapto propionate, di-n-octyltin polymeric maleate, bis-S, S' - (isooctylmercaptoacetate) di-n-octyltin, and ß- di-n-octyltin mercapto propionate. Monoalkylated derivatives of the aforementioned compounds are also suitable. As a mineral-type hydrochloric acid scrubber, mention may also be made of aluminum or magnesium sulfate or carbonate, especially of the hydrotalcite type. It should be remembered that the hydrotalcite compounds correspond to the formula Mgx_xAlx (OH) 2An "x / nmH20 where x is in the range of 0 (excluded) and 0.5, An ~ represents an anion, for example, a carbonate, Nitrogen varies from 1 to 3, and m is positive It should be mentioned that it is possible to use products of this type which have undergone a surface treatment with an organic compound The scope of the present invention encompasses the use of a product of the hydrotalcite type. corrected with zinc, which has optionally passed through a surface treatment with an organic compound, Among the products of this type, mention may be made in particular of Alcamizer®4 (sold by Kyo a) It is also possible to use essentially amorphous compounds of the formula (MgO) y, Al203, (C02) x, (H20) z, where x, y and z satisfy the following inequalities: 0 <; x < 0.7; 0 < and < 1.7, and z > 3. These compounds are described in particular in the patent application EP-A-0 509 864. Moreover, the compounds which are called catoítos, of formula Ca3Al2 (OH) 12 otherwise Ca3Al2 (SiO) 4 (OH) 12 , 'are suitable as inorganic-type hydrochloric acid scavenging compounds. The formulations based on the halogenated polymers can also comprise titanium dioxide. Preferably, the titanium dioxide is in the form of rutile. Generally, the particle size of the titanium dioxide that forms part of the stabilizer compositions according to the invention is 0.1 to 0.5 μm. According to an embodiment of the invention, use is made of titanium dioxide in the form of rutile which has undergone a surface treatment, preferably mineral. Non-limiting examples of suitable titanium dioxides which can be used with the present invention are the titanium dioxides Rhoditan®, RL 18 and Rhoditan® RL 90, sold by Rhodia Chimie, and the titanium dioxides KRONOS. 2081® AND 2220® sold by KRONOS. The "formulations based on halogenated polymers can also comprise other white or colored pigments.

Among the color pigments, cerium sulphide can be mentioned. It should be mentioned that the amount of pigment introduced into the formulation can vary within wide limits and depends on the pigment coloring powder and the desired final coloration. However, by way of example, the amount of pigment can vary from 0.1 to 20 g per lOOg of halogenated polymer, preferably from 0.5 to 15 g in relation to the same reference. The formulation may additionally comprise at least one polyol containing from 2 to 32 carbon atoms and having between two and nine hydroxyl groups. Among these compounds are the C3-C30 diols, for example, propylene glycol, butanediol, hexanediol, dodecanediol, neopentyl glycol, polyols, for example, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, xylitol, mannitol, sorbitol and glycerol, and mixtures thereof. glycerol oligomers with a degree of polymerization of 2 to 10. Another family of polyols that can be suitably used consists of partially acetylated polyvinyl alcohols. It is also possible to use hydroxy compounds containing isocyanurate groups, together or in combination with the aforementioned polyols, for example, tris (2-hydroxyethyl) isocyanurate. The amount of polyol used is generally 0.05 to 5 g per 100 g of polymer. More specifically, it is less than 2 g per 100 g of halogenated polymer.

It is also possible, if desired, to incorporate in the formulation compounds of the organic phosphite type, for example, trialkyl, aryl, triaryl, dialkylaryl or diarylalkyl phosphites, wherein the term alkyl denotes polyols or monoalcohols of the C8 hydrocarbon groups -C22, and the term aryl denotes aromatic phenol or phenol groups substituted by C3-C12 alkyl groups. It is also possible to use calcium phosphites, for example, compounds of the Ca type (HP03) (H20), and also phosphite-hydroxy-aluminum-calcium complexes. The amount of additive of this type is generally 0.1 to 2 g per 100 halogenated polymer. The formulations may also include at least one synthetic crystalline alkali metal aluminosilicate having a water content between 13 and 25% by weight, of the composition 0.7-lM20-Al203.1.3 -2.4 Si02, wherein M represents an alkali metal , for example, sodium. Zeolites of the NaA type are also suitable, as described in US Pat. No. 4,590,223. The amount of this type of compound generally varies between 0.1 and 5 g per 100 g halogenated polymer. The formulations may also include epoxide type compounds. These compounds are generally selected from epoxidized polyglycerides or epoxidized fatty acid esters, for example, flaxseed oil, soybean or epoxidized fish oils. The amount of the compounds of this type generally varies between 0.5 and 10 g per 100 g of resin. Other conventional additives can round the formulation, depending on the intended application. As a general rule, the formulation may include phenolic antioxidants, anti-UV agents, for example, 2-hydroxybenzophenones, 2-hydroxybenzotriazoles or sterically hindered amines, commonly known as Hals. The amount of this type of additive generally varies between 0.05 and 3 g per 100 g of halogenated polymer. If necessary, it is also possible to use lubricants that will facilitate the use of the composition, selecting these lubricants of glyceryl monostearate or, otherwise, propylene glycol, fatty acids or their esters, montanato waxes, polyethylene waxes or their derivatives oxidized, paraffins, metallic soaps and functionalized polymethylsiloxane oils, for example, Y-hydroxypropylenated oils. The amount of lubricant that forms part of the formulation based on the halogenated polymer generally varies between 0.05 and 2 g of per 100 g of resin. The formulation may also include plasticizers selected from alkyl phthalates. The most commonly used compounds are selected from di (2-ethylexyl) phthalate, the linear esters of dibasic acid with C6-C12, and phosphate esters. The amount of plasticizer used in the formulations varies greatly, depending on the rigid or flexible nature of the final polymer. As an indication, the amount varies from 0 to 100 g per 100 g of polymer. The formulations can be prepared by means known to those skilled in the art. The various constituents can be incorporated into the polymer individually or after having prepared a mixture of two or more of these constituents in advance.; for example, the stabilizing composition of the invention alone or with the presence of the lubricant. Conventional methods of incorporation are ideally suited to the production of the PVC-based formulation. Therefore, and only by way of indication, it is possible to carry out this operation in a mixer equipped with a paddle and paddle system operating at high speed. In general, the temperature at which the constituents of the formulation are incorporated is lower than 130 ° C.

Once the mixture has been prepared, the composition is formed by applying the methods customary in the industry, for example molding "by injection, extrusion-blow molding, extrusion, calendering or rotary molding." The temperature at which the forming is performed generally ranges from 150 to 220 ° CA, non-limiting examples will be described below.Example 1 This example illustrates the preparation of a coated calcium acetylacetonate 1. Preparation of calcium acetylacetonate coated with stearic acid (El) A coating solution was prepared adding 3 g of stearic acid to 150 ml of hexane, heating the mixture to 55 ° C, with stirring, 57 g of calcium acetylacetonate were added to this mixture with stirring.The operation was carried out without stirring at atmospheric pressure and temperature The mixture was stirred for 45 minutes, drying was carried out as follows: • gradual and constant elimination of the main solvent (350 mbar, 55-60 ° C); • drying at 55-60 ° C at a pressure of 10 to 15 mbar; The resulting solid reaction mass was recovered, ground and dried in a vacuum at 10 mbar at a temperature of 55-60 ° C. 2. Preparation of calcium acetylacetonate with a silicone oil (E2) A coating solution was prepared by adding 3 g of stearic acid to 200 ml of hexane, the mixture being heated to 60 ° C, with stirring. 57 g of calcium acetylacetonate were added to this solution. The operation was carried out without agitation, at atmospheric pressure and at 60 ° C. The mixture was stirred for 2 hours, drying was carried out as follows: • gradual and constant elimination of the main portion of the solvent (450 mbar, 60 ° C) • dried at 60 ° C at a pressure of 50 mbar • recovered the resulting solid reaction mass, ground and dried in a vacuum at 10 mbar at a temperature of 60 ° C. EXAMPLE 2 This example evaluates the degree of dispersion of the coated or uncoated calcium acetylacetonate Three samples were prepared with the formulation with the composition shown in the table below: • PVC resin prepared by polymerization of 100 parts suspension, S110P® sold by Atochem • Ti02 ( Kronos 2220®) 6.0 parts • Stabilizer: Stavinor® (Atochem) hydroxystearate 0.3 parts ZN70® zinc stearate (Atochem) 1 part • Alcamizer 4® (Mitsui) hydrotalcite 0.6 parts • Polyvinyl PVAL® polyvinyl alcohol 0.2 parts • Hydrocarb CaC02 95 T® _- (Omaya) 5.0 parts • Shock enhancer - Paraloid KM 355® 6.5 parts (Rohm &Hass) • Loxiol G 60® lubricants (Henkel) 0.4 parts Loxiol G 22® (Henkel) 0.2 parts • Paraloid K 120N® processing aid 1 part (Rohm &Haas) In the first example, comparative EO, calcium acetylacetonate was introduced in an amount of 0.3 parts per 100 parts of PVC resin. In the second example, according to the invention, obtained above, calcium acetylacetonate coated with stearic acid (0.3 parts per 100 parts of PVC resin) was introduced. In the third example E2, according to the invention, obtained above, calcium acetylacetonate coated with silicone oil (0.3 parts per 1000 parts of PVC resin) was introduced Powders were mixed with the Papen Meier fast mixer (rotation speed 2500 rpm). The mixing operation was stopped when the mixture reached a temperature of 113-115 ° C. For this mixture of powders, the transformation was carried out by extrusion to obtain sheets. The twin screw extruder had the following characteristics: Produced by Brabender Parallel screw: length / radius diameter: 42/6 D SK Flat die The conditions of the extrusion to produce profiles were: • Screw rotation speed: 20 rpm; Temperature profile zone 1 _ zone 2 zone 3 175 ° 185 ° C 185 ° C "The yellow index (coefficient b) of the extruded plates obtained was then measured The coefficient b is a coefficient of the parameters of the CIÉ (L, a, b) of the system The indexes were measured in extruded plates using a MINOLTA CR2000® colorimeter / colorimeter The results are shown in the following table:ot.

It should be mentioned that the yellow index reflects the degree of dispersion of calcium acetylacetonate in the polymeric formulation. Thus, an improvement in this index (that is, the reduction in the value of the coefficient) indicates better dispersion. Therefore, it can be seen that the samples El and E2 of the invention are better dispersed than the comparative sample EO. EXAMPLE 3 This example illustrates the preparation of calcium acetylacetonate coated with stearyl alcohol. A coating solution was prepared by the addition of 2.5 g of stearyl alcohol to 120 ml of hexane, the mixture was heated to 60 ° C, with stirring. 45 g of calcium acetylacetonate were added to this solution. The operation was carried out without agitation, at atmospheric pressure and at room temperature. The drying was carried out as follows: • gradual and constant elimination of the main portion of the solvent (350 mbar, 55-60 ° C); dried at 55-60 ° C at a pressure of 8 to 18 mbar. EXAMPLE 4 This example evaluates the degree of dispersion of the coated or uncoated calcium acetylacetonate. 1. Preparation of the black master mix The composition was as follows: The powders are mixed in a Hobart® mixer (planetary Kenwood type) for 30 minutes. Next, the liquid compounds were added with stirring at a temperature of 50 ° C, for 30 minutes. The stirring was maintained for 1 hour at 50 ° C. 2. Calendering The black masterbatch obtained above is used, first, in the form of a coated calcium acetylacetonate obtained in Example 3 (E3, according to the invention) and, second, in the form of a sample of acetylacetonate from Calcium alone (EO, comparative), in a Troester® roller mixer. (a) characteristics of the Troester® apparatus type WNK 1 No. 1355 double roller mixer. Rollers: diameter: 101 mm; long 250 mm. The rollers rotate at a speed of 29 rpm; The coefficient of friction was l / l (coefficient of friction zero); The roller temperature was 175 ° C. (b) Procedure 100 g of the black master batch obtained in point 1 are gelled. After 90 seconds of calendering, the gap between the rolls was adjusted to 0.7 (1 mm sheet thickness), 2.5 g of acetylacetonate (by one side in the form of sample E0, and on the other hand in the form of sample E3). Finally, a "fine" pass was made with a roller spacing of 0.4, after calendering for 210 seconds, a sheet of 1 mm thickness was produced (roller spacing to 0.7) and the sheets obtained were cooled. calenders are visually compared The number of white spots appearing on the black background of the leaf characterizes the dispersion state of calcium acetylacetonate The number of visible agglomerates or pitting was lower than in the case of the leaf comprising the sample E3, in comparison with the sheet comprising the EO sample, demonstrating a better dispersion of the coated compound of the invention in the polymer formulation.

Claims (12)

1. CLAIMS 1. Particles comprising calcium or magnesium acetylacetonate or a combination of both, partially or completely coated with at least one compatibilizing agent selected from: alcohols containing from 12 to 30 carbon atoms, which may be saturated or unsaturated; carboxylic or sulphonic acids containing from 12 to 30 carbon atoms, which may be saturated or unsaturated, substituted or unsubstituted with at least one hydroxyl group, or derivatives thereof; phosphates or titanates comprising at least one chain containing from 12 to 30 carbon atoms, which may be saturated or unsaturated; • - ß-diketone compounds with at least one chain containing at least 7 carbon atoms; waxes; • polyols; epoxidized vegetable oils; • polysiloxane oils or resins or silanes. 2. The particles according to the preceding claim, characterized in that the compatibilizing agent is an alcohol selected from saturated or unsaturated aliphatic monoalcohols containing from 12 to 30 carbon atoms.
2. [O
3. 3. The particles according to the preceding claim, characterized in that the alcohol is selected from lauric, myristic, isostearic, cetyl, behenic, lauroleic, erucic and linoleic alcohol.
4. 4. The particles according to claim 1, characterized in that the compatibilizing agent is selected from carboxylic acids such as stearic acid, lauric, myristic, palmitic, oleic, ricinoleic, behenic (docosanoic), linoleic, hydroxystearic, or any other acid that originates in glycerides or triglycerides, natural or otherwise.
5. 5. The particles according to claim 1, characterized in that the compatibilizing agent is selected from carboxylic acids obtained from monoalcohols containing 1 30 carbon atoms, or mono or polyesters obtained from polyols.
6. 6. The particles according to claim 1, characterized in that the compatibilizing agent is derived from alkaline or earth-alkaline metals, aluminum, lanthanum or zinc salts of the carboxylic acids.
7. 7. The particles according to claim 1, characterized in that the compatibilizing agent is docetylbenzensulfonic acid.
8. 8. The particles according to claim 1, characterized in that the compatibilizing agent is a ß-diketone compound with formula R1COCHR2COR3; wherein the radical R1 represents a linear or branched C7-C30 hydrocarbon radical, substituted or unsubstituted, the radical R3 represents a linear or branched C1-C30 hydrocarbon radical, substituted or unsubstituted and R2 is a hydrogen atom or a radical linear or branched C1-C4 hydrocarbon.
9. 9. The particles according to claim 1, characterized in that the compatibilizing agent is selected from waxes, for example, montanate waxes, polyethylene waxes or their oxidized derivatives and paraffins.
10. 10. The particles according to claim 1, characterized in that the compatibilizing agent is selected from polyols containing from 2 to 32 carbon atoms carrying from two to nine hydroxyl groups, and wherein the hydroxyl groups can be found in the close or not, or polyvinyl alcohols, or polyols containing isocyanurate groups.
11. 11. The particles according to the preceding claim, characterized in that the polyol is selected from propylene glycol, butanediol, hexanediol, dodecanediol, neopentyl glycol, polyols, for example, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, xylitol, mannitol , sorbitol and glycerol, and mixtures of glycerol oligomers with a degree of polymerization of 2 to 10, hydroxystearic alcohol or ricinoleyl alcohol.
12. 12. The particles according to claim 1, characterized in that the compatibilizing agent is a polysiloxane oil corresponding to the following general formula: YO- [(R) Si (R) -O] X-Y, wherein the radicals R, which may be identical or different, represent an alkyl radical containing from 1 to 3 carbon atoms, preferably a methyl radical, or a hydrogen atom, as long as one of the two radicals is a hydrogen atom, and represents a hydrogen atom or (R ') 3Si in which the radicals R', which may be identical 0 different, represent an alkyl radical containing 1 to 3 carbon atoms, preferably methyl. The coefficient x can vary within a wide range, but more particularly it is in the range of 5 to 300. The particles according to the preceding claim, characterized in that the compatibilizing agent is a polysiloxane oil selected from oils of functionalized polymethylsiloxane, for example, Y-hydroxypropylenated oils. 15. The particles according to claim 1, characterized in that the compatibilizing agent is selected from polysiloxane resins obtained by the action of oils carrying vinyl groups in the presence of a platinum-based catalyst, or from those obtained by the hydrolysis and self-condensation of at least one silane of formula (RO) 3SiF or (RO) 2 (Me) SiF wherein R, which may be identical or different, represents an alkyl radical containing from 1 to 4 carbon atoms, more particularly, F represents the following radicals: -CH = CH2; - (CH2) 3OH; - (CH2) 3-NH- (CH2) 3NH2CH2CH2NH2; - (CH2) 3OCH2CHCH2; 0 / - (CH2) 3OCO-CH = CH2 - (CH2) 3OCO- (CH3) CH = CH2 or of the aforementioned silanes as they are. 16. The particles according to any of the preceding claims, characterized in that the proportion by weight of the compatibilizing agent with respect to calcium or magnesium acetylacetonate is in the range of 0.1% to 20% by weight with respect to the weight of the calcium or magnesium acetylacetonate, more particularly in the range of 0.1% to 10% by weight based on the weight of calcium or magnesium acetylacetonate. 17. A process for preparing particles according to any of the preceding claims, characterized in that the acetylacetonate is contacted with at least one compatibilizing agent in the presence of a solvent or dispersing agent, or both. 18. A process according to the preceding claim, characterized in that the solvent or dispersing agent is selected from water, from C1-C5 monoalcohols, in particular methanol or ethanol, C2-C6 ethers such as dimethyl ether, methylethyl ether, diethyl ether and hydrocarbons, for example, hexane. 19. The use of the particles according to any of claims 1 to 16, as an additive in formulations comprising at least one halogenated polymer. The use according to the preceding claim, characterized in that the quantity of particles, expressed as calcium or magnesium acetylacetonate, is in the range of 0.01 to 5 g per 100 g of halogenated polymer, more particularly between 0.05 and 2 g with respect to the same reference.