Patent Publication Number: US-6211270-B1

Title: Cyanoacetylureas for stabilizing halogenated polymers

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates to the compositions consisting of chlorine-containing polymers and cyanoacetylureas which are of the formula I depicted below and are intended for stabilizing these polymers, especially PVC. 
     2. Prior Art 
     PVC can be stabilized by a range of additives. Compounds of lead, of barium and of cadmium are particularly suitable for this purpose but are nowadays controversial on ecological grounds or because of their heavy metal content (cf. “Kunststoffadditive”, R. Gächter/H. Müller, Carl Hanser Verlag, 3rd ed., 1989, pages 303-311, and “Kunststoff Handbuch PVC”, volume 2/1, W. Becker/D. Braun, Carl Hanser Verlag, 2nd ed., 1985, pages 531-538; and also Kirk-Othmer: “Encyclopedia of Chemical Technology”, 4 th  ed., 1994, Vol. 12, Heat Stabilizers, pp. 1071-1091). The search therefore continues for effective stabilizers and stabilizer combinations which are free from lead, barium and cadmium. 
     Some of the compounds of the formula I are novel substances while others are known. Representatives of the formula I have been described, for example, in U.S. Pat. No. 2,598,936 and J. Org. Chem. 16, 1879-1890 (1951) and can be prepared by known methods in one or more process steps. The initial ureas are obtainable commercially or can be prepared by known methods. 
     SUMMARY OF THE INVENTION 
     It has now been found that cyanoacetylureas of the general formula I                    
     where 
     X is oxygen or sulfur, and 
     R is C 2 -C 22 -acyloxyalkyl or C 1 -C 12 -alkyl which may be interrupted by 1 to 3 oxygen atoms and/or substituted by 1 to 3 OH groups, or is C 3 -C 8 -alkenyl, C 7 -C 10 -phenylalkyl, C 5 -C 8 -cycloalkyl, C 7 -C 10 -alkylphenyl, phenyl or naphthyl, where the aromatic radical in each case may be substituted by —OH, C 1 -C 12 -alkyl and/or OC 1 -C 4 -alkyl, and 
     R 1  is hydrogen or is as defined for R, are particularly suitable for stabilizing chlorine-containing polymers such as PVC, for example. 
     For compounds of the formula I: 
     C 1 -C 4 -alkyl is, for example, methyl, ethyl, n-propyl, iso-propyl, n-, i-, sec- or t-butyl. 
     C 1 -C 12 -alkyl is, for example, the radicals just mentioned and also pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, i-octyl, decyl, nonyl, undecyl or dodecyl. Preference is given to C 1 -C 4 -alkyl, uninterrupted or interrupted by —CO 2 —. 
     C 5 -C 8 -Cycloalkyl is, for example, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl, preferably cyclohexyl. 
     C 7 -C 10 -Alkylphenyl is, for example, tolyl, xylyl or mesityl, especially tolyl and xylyl. 
     C 7 -C 10 -Phenylalkyl is, for example, benzyl, 1- or 2-phenylethyl, 3-phenylpropyl, α,α-dimethylbenzyl or 2-phenylisopropyl, preferably benzyl and 2-phenethyl, especially benzyl. 
     If the aromatic radical is substituted then it is preferably substituted by three, two or, in particular, one substituent and the substituents are, in particular, hydroxyl, methyl, ethyl, methoxy or ethoxy. 
     C 3 -C 8 -Alkenyl is, for example, allyl, methallyl, 1-butenyl, 1-hexenyl, 1-octenyl or 2-octenyl, preferably allyl or methallyl. 
     Examples of C 2 -C 22 -acyloxyalkyl are branched or straight-chain radicals such as, for example, acetoxyethyl, propionyloxyethyl, acetoxypropyl, acetoxybutyl, propionyloxybutyl, benzoxyethyl, benzoxypropyl, benzoxybutyl, phenylpropionyloxyethyl, phenylpropionyloxypropyl, phenylpropionyloxybutyl, etc., where the phenyl radical may be substituted by 1 to 3 —OH and/or 1 to 3 C 1 -C 4 -alkyl radicals (branched and unbranched). 
     Preference is given, for example, to acetoxyethyl and benzoxyethyl. 
     Preference is given to compounds of the formula I in which X is oxygen, and to those in which the radicals R and R 1  are identical. Also judicious are compounds in which X is sulfur. 
     Preference is also given to compounds of the formula I in which R and R 1  are C 1 -C 8 -alkyl, C 3 -C 5 -alkenyl, benzyl or 2-phenethyl. 
     Particular preference is given to compounds of the formula I in which R and R 1  are C 1 -C 4 -alkyl, allyl or benzyl. 
     In order to achieve stabilization in the chlorine-containing polymer, the compounds of the formula I are to be used in a proportion of judiciously from 0.01 to 10% by weight, preferably from 0.05 to 5% by weight and, in particular, from 0.1 to 3% by weight. 
     It is also possible to employ combinations of compounds of the general formula I with other customary additives and stabilizers, for example with polyols and disaccharide alcohols and/or perchlorate compounds and/or glycidyl compounds and/or zeolite compounds and/or layered lattice compounds (hydrotalcites) and also, for example, light stabilizers. Examples of such additional components are listed and elucidated below. 
     SUMMARY OF THE INVENTION 
     Polyols and Disaccharide Alcohols 
     Examples of suitable compounds of this type are: pentaerythritol, dipentaerythritol, tripentaerythritol, trimethylolethane, bistrimethylolpropane, inositol (cyclitols), polyvinyl alcohol, bistrimethylolethane, trimethylolpropane, sorbitol (hexitols), maltitol, isomaltitol, cellobiitol, lactitol, lycasine, mannitol, lactose, leucrose, tris(hydroxyethyl) isocyanurate, tris(hydroxypropyl) isocyanurate, palatinitol, tetramethylolcyclohexanol, tetramethylolcyclopentanol, tetramethylolcyclopyranol, xylitol, arabinitol (pentitols), tetritols, glycerol, diglycerol, polyglycerol, thiodiglycerol or 1-O-α-D-glycopyranosyl-D-mannitol dihydrate. 
     Of these, preference is given to the disaccharide alcohols. 
     It is also possible to use polyol syrups, such as sorbitol, mannitol and maltitol syrup. 
     The polyols can be employed in an amount of, for example, from 0.01 to 20, judiciously from 0.1 to 20 and, in particular, from 0.1 to 10 parts by weight per 100 parts by weight of PVC. 
     Perchlorate Compounds 
     Examples are those of the formula M(ClO 4 ) n , in which M is Li, Na, K, Mg, Ca, Sr, Ba, Zn, Al, La or Ce. Depending on the valency of M, the index n is 1, 2 or 3. The perchlorate salts can be present as solutions or can have been complexed with alcohols (polyols, cyclodextrins) or ether alcohols or ester alcohols. The ester alcohols also include the polyol partial esters. In the case of polyhydric alcohols or polyols, their dimers, trimers, oligomers and polymers are also suitable, such as di-, tri-, tetra- and polyglycols and also di-, tri- and tetrapentaerythritol or polyvinyl alcohol in various degrees of polymerization. Other suitable solvents are phosphate esters and also cyclic and acyclic carbonates. 
     In this context, the perchlorate salts can be employed in various common forms of presentation; for example, as a salt or solution in water or an organic solvent as such, or adsorbed on a support material such as PVC, Ca silicate, zeolites or hydrotalcites, or bound by chemical reaction into a hydrotalcite or into another layered lattice compound. As polyol partial ethers, preference is given to glycerol monoethers and glycerol monothioethers. 
     Further embodiments are described in EP 0 394 547, EP 0 457 471 and WO 94/24200. 
     The perchlorates can be employed in an amount of, for example, from 0.001 to 5, judiciously from 0.01 to 3, and, with particular preference, from 0.01 to 2 parts by weight per 100 parts by weight of PVC. 
     Glycidyl Compounds 
     These contain the glycidyl group                    
     attached directly to carbon, oxygen, nitrogen or sulfur atoms, and in such compounds R 1  and R 3  are either both hydrogen and R 2  is hydrogen or methyl and n is 0 or R 1  and R 3  together are —CH 2 —CH 2 — or —CH 2 —CH 2 —CH 2 — and in that case R 2  is hydrogen and n is 0 or 1. 
     I) Glycidyl esters and β-methylglycidyl esters obtainable by reacting a compound having at least one carboxyl group in the molecule with epichlorohydrin or glyceroldichlorohydrin or β-methylepichlorohydrin. The reaction takes place judiciously in the presence of bases. 
     As compounds having at least one carboxyl group in the molecule it is possible to use aliphatic carboxylic acids. Examples of these carboxylic acids are glutaric, adipic, pimelic, suberic, azelaic and sebacic acid or dimerized or trimerized linoleic acid, acrylic and methacrylic acid, caproic, caprylic, lauric, myristic, palmitic, stearic and pelargonic acid, and also the acids mentioned in connection with the organozinc compounds. 
     However, it is also possible to employ cycloaliphatic carboxylic acids, such as, for example, cyclohexanecarboxylic, tetrahydrophthalic, 4-methyltetrahydrophthalic, hexahydrophthalic or 4-methylhexahydrophthalic acid. Aromatic carboxylic acids can also be used, examples being benzoic, phthalic, isophthalic, trimellitic and pyromellitic acid. 
     It is likewise possible to make use of carboxyl-terminated adducts of, for example, trimellitic acid with polyols, such as glycerol or 2,2-bis(4-hydroxycyclohexyl)propane. 
     Other epoxide compounds which can be used in the context of this invention are given in EP 0 506 617. 
     II) Glycidyl ethers or β-methylglycidyl ethers obtainable by reacting a compound having at least one free alcoholic hydroxyl group and/or phenolic hydroxyl group with an appropriately substituted epichlorohydrin under alkaline conditions or in the presence of an acidic catalyst with subsequent alkali treatment. 
     Ethers of this type are derived, for example, from acyclic alcohols, such as ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, propane-1,2-diol, or poly(oxypropylene) glycols, propane-1,3-diol, butane-1,4-diol, poly(oxytetramethylene) glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol, glycerol, 1,1,1-trimethylolpropane, bistrimethylolpropane, pentaerythritol, sorbitol, and from polyepichlorohydrins, butanol, amyl alcohol, pentanol, and from monofunctional alcohols such as isooctanol, 2-ethylhexanol, isodecanol and also C 7 -C 9 -alkanol and C 9 -C 11 -alkanol mixtures. 
     They are also derived, however, for example, from cycloaliphatic alcohols, such as 1,3- or 1,4-dihydroxycyclohexane, bis(4-hydroxycyclohexyl)methane, 2,2-bis-(4-hydroxycyclohexyl)propane or 1,1-bis(hydroxymethyl)cyclohex-3-ene, or they possess aromatic nuclei, such as N,N-bis(2-hydroxyethyl)aniline or p,p′-bis(2-hydroxyethylamino)diphenylmethane. 
     The epoxide compounds can also be derived from mononuclear phenols, such as, for example, from phenol, resorcinol or hydroquinone; or, they are based on polynuclear phenols, such as, for example, on bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxyphenyl)-propane, on 4,4′-dihydroxydiphenyl sulfone or on condensates of phenols with formaldehyde obtained under acidic conditions, such as phenol novolaks. 
     Examples of further possible terminal epoxides are: glycidyl 1-naphthyl ether, glycidyl 2-phenylphenyl ether, 2-biphenylyl glycidyl ether, N-(2,3-epoxypropyl)phthalimide and 2,3-epoxypropyl 4-methoxyphenyl ether. 
     III) N-Glycidyl compounds obtainable by dehydrochlorination of the reaction products of epichlorohydrin with amines containing at least one amino hydrogen atom. These amines are, for example, aniline, N-methylaniline, toluidine, n-butylamine, bis(4-aminophenyl)methane, m-xylylenediamine or bis-(4-methylaminophenyl)methane, and also N,N,O-triglycidyl-m-aminophenol or N,N,O-triglycidyl-p-aminophenol. 
     However, the N-glycidyl compounds also include N,N′-di-, N,N′,N″-tri- and N,N′,N″,N′″-tetraglycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1,3-propyleneurea and N,N′-diglycidyl derivatives of hydantoins, such as of 5,5-dimethylhydantoin or glycoluril and triglycidyl isocyanurate. 
     IV) S-Glycidyl compounds such as di-S-glycidyl derivatives derived from dithiols, such as ethane-1,2-dithiol or bis(4-mercaptomethylphenyl) ether, for example. 
     V) Epoxy compounds having a radical of the formula I in which R 1  and R 3  together are —CH 2 -CH 2 — and n is 0 are bis(2,3-epoxycyclopentyl) ether, 2,3-epoxycyclopentylglycidyl ether or 1,2-bis(2,3-epoxycyclopentyloxy) ethane. An epoxy resin having a radical of the formula I in which R 1  and R 3  together are —CH 2 -CH 2 — and n is 1 is, for example, (3′,4′-epoxy-6′-methylcyclohexyl)methyl 3,4-epoxy-6-methylcyclohexanecarboxylate. 
     Examples of suitable terminal epoxides are: 
     a) liquid bisphenol A diglycidyl ethers, such as Araldit®GY 240, Araldit®GY 250, Araldit®GY 260, Araldit®GY 266, Araldit®GY 2600, Araldit®790; 
     b) solid bisphenol A diglycidyl ethers, such as Araldit®GT 6071, Araldit®GT 7071, Araldit®GT 7072, Araldit®GT 6063, Araldit®GT 7203, Araldit®GT 6064, Araldit®GT 7304, Araldit®GT 7004, Araldit®GT 6084, Araldit®GT 1999, Araldit®GT 7077, Araldit®GT 6097, Araldit®GT 7097, Araldit®GT 7008, Araldit®GT 6099, Araldit®GT 6608, Araldit®GT 6609, Araldit®GT 6610; 
     c) liquid bisphenol F diglycidyl ethers, such as Araldit®GY 281, Araldit®PY 302, Araldit®PY 306; 
     d) solid polyglycidyl ethers of tetraphenylethane, such as CG Epoxy Resin®0163; 
     e) solid and liquid polyglycidyl ethers of phenol-formaldehyde novolak, such as EPN 1138, EPN 1139, GY 1180, PY 307; 
     f) solid and liquid polyglycidyl ethers of o-cresol-formaldehyde novolak, such as ECN 1235, ECN 1273, ECN 1280, ECN 1299; 
     g) liquid glycidyl ethers of alcohols, such as Shell®Glycidyl ether 162, Araldit®DY 0390, Araldit®DY 0391; 
     h) liquid glycidyl ethers of carboxylic acids, such as Shell®Cardura E terephthalic acid ester, trimellitic acid ester, Araldit®PY 284; 
     i) solid heterocyclic epoxy resins (triglycidyl isocyanurate), such as Araldit®PT 810; 
     j) liquid cycloaliphatic epoxy resins such as Araldit®CY 179; 
     k) liquid N,N,O-triglycidyl ethers of p-aminophenol, such as Araldit®MY 0510; 
     l) tetraglycidyl-4,4′-methylenebenzamine or N,N,N′,N′-tetraglycidyldiaminophenylmethane, such as Araldit®MY 720, Araldit®MY 721. 
     Preference is given to the use of epoxy compounds having two functional groups. In principle, however, it is also possible to employ epoxy compounds having one, three or more functional groups. 
     Use is made predominantly of epoxy compounds, especially diglycidyl compounds, having aromatic groups. 
     If desired, it is also possible to employ a mixture of different epoxy compounds. Particular preference is given as terminal epoxy compounds to diglycidyl ethers based on bisphenols, such as on 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane or mixtures of bis(ortho/parahydroxyphenyl)methane (bisphenol F), for example. 
     The terminal epoxy compounds can be employed in an amount of preferably at least 0.1 part, for example from 0.1 to 50, judiciously from 1 to 30 and in particular, from 1 to 25 parts by weight, per 100 parts by weight of PVC. 
     Hydrotalcites and Alkaline (Earth) Metal Alumosilicates (Zeolites) 
     The chemical composition of these compounds is known to the person skilled in the art, for example, from patents DE 3 843 581, U.S. Pat. No. 4,000,100, EP 0 062 813 and WO 93/20135. 
     Compounds from the series of the hydrotalcites can be described by the following general formula 
     
       
         M 2+   1−x M 3+   x (OH) 2 (A b− ) x/b ·dH 2 O 
       
     
     where 
     M 2+ =one or more metals from the group Mg, Ca, Sr, Zn and Sn, 
     M 3+ =Al, or B, 
     A n  is an anion having the valency n, b is a number from 1-2, 
     
       
         0&lt;×&lt;0.5, 
       
     
     m is a number from 0-20. 
     Preferably 
     A n =OH — , ClO 4   — , HCO 3   — , CH 3 COO — , C 6 H 5 COO — , CO 3   2— , (CHOHCOO) 2   2— , (CH 2 COO) 2   2— , CH 3 CHOHCOO — , HPO 3   —  or HPO 4   2— ; 
     Examples of hydrotalcites are 
     Al 2 O 3 .6 MgO.CO 2 .12 H 2 O (i), Mg 4,5 Al 2 (OH) 13 .CO 3 .3.5 H 2 O (ii), 4 MgO.Al 2 O 3 .CO 2 .9 H 2 O (iii), 4 MgO.Al 2 O 3 .CO 2 .6 H 2 O, ZnO.3 MgO.Al 2 O 3 .CO 2 .8-9 H 2 O and ZnO.3 MgO.Al 2 O 3 .CO 2 .5-6 H 2 O. Very particular preference is given to types i, ii and iii. 
     Zeolites (Alkali Metal and Alkaline Earth Metal Alumosilicates) 
     These can be described by the following general formula 
     
       
         M x/n [(AlO 2 ) x (SiO 2 ) y ].wH 2 O 
       
     
     in which n is the charge of the cation M; 
     M is an element from the first or second main group, such as Li, Na, K, Mg, Ca, Sr or Ba; 
     y: x is a number from 0.8 to 15, preferably from 0.8 to 1.2; and 
     w is a number from 0 to 300, preferably from 0.5 to 30. 
     Examples of zeolites are sodium aluminosilicates of the formulae 
     Na 12 Al 12 Si 12 O 48 .27 H 2 O [zeolite A], Na 6 Al 6 Si 6 O 24 .2 NaX.7.5 H 2 O, X=OH, halogen, ClO 4  [sodalite]; Na 6 Al 6 Si 30 O 72 .24 H 2 O; Na 8 Al 8 Si 40 O 96 . 24 H 2 O; Na 16 Al 16 Si 24 O 80 .16 H 2 O; Na 16 Al 16 Si 32 O 96 .16 H 2 O; Na 56 Al 56 Si 136 O 384 . 250 H 2 O [zeolite Y], Na 86 Al 86 Si 106 O 384 . 264 H 2 O [zeolite X]; 
     or the zeolites preparable by complete or partial replacement of the Na atoms by Li, K, Mg, Ca, Sr or Zn atoms, such as 
     (Na,K) 10 Al 10 Si 22 O 64 . 20 H 2 O; Ca 4,5 Na 3 [(AlO 2 ) 12 (SiO 2 ) 12 ]. 30 H 2 O; K 9 Na 3 [(AlO 2 ) 12 (SiO 2 ) 12 ].27 H 2 O, 
     Preferred zeolites are those of the formulae 
     Na 12 Al 12 Si 2 O 48 .27 H 2 O [zeolite A], 
     Na 6 Al 6 Si 6 O 24 . 2 NaX.7.5 H 2 O, X=OH, Cl, ClO 4 , ½CO 3  [sodalite] Na 6 Al 6 Si 30 O 72 .24 H 2 O, 
     Na 8 Al 8 Si 40 O 96 . 24 H 2 O, 
     Na 16 Al 16 Si 24 O 80 .16 H 2 O, 
     Na 16 Al 16 Si 32 O 96 .16 H 2 O, 
     Na 56 Al 56 Si 136 O 384 .250 H 2 O [zeolite Y], 
     Na 86 Al 86 Si106O 384 .264 H 2 O [zeolite X] 
     and those X and Y zeolites having an Al/Si ratio of about 1:1, or the zeolites preparable by complete or partial replacement of the Na atoms by Li, K, Mg, Ca, Sr, Ba or Zn atoms, such as 
     (Na,K) 10 Al 10 Si 22 O 64 .20 H 2 O. 
     Ca 4,5 Na 3 [(AlO 2 ) 12 (SiO 2 ) 12 ].30 H 2 O 
     K 9 Na 3 l(AlO 2 ) 12 (SiO 2 ) 12 .27 H 2 O 
     The zeolites indicated can also be lower in water content, or anhydrous. 
     Further suitable zeolites are: 
     Na 2 O.Al 2 O 3 .(2 to 5) SiO 2 .(3.5 to 10) H 2 O[zeolite] 
     Na 2 O.Al 2 O 3 .2 SiO 2 .(3.5-10)H 2 O (zeolite MAP) 
     or the zeolites preparable by complete or partial replacement of the Na atoms by Li, K or H atoms, such as 
     (Li,Na,K,H) 10 Al 10 Si 22 O 64 . 20 H 2 O. 
     K 9 Na 3 [(AlO 2 ) 12 (SiO 2 ) 12 ].27 H 2 O 
     K 4 Al 4 Si 4 O 16 .6 H 2 O [zeolite K-F] 
     Na 8 Al 8 Si 40 O 96 .24 H 2 O [zeolite D], as described in Barrer et al., J. Chem. Soc. 1952, 1561-71, and in U.S. Pat. No. 2,950,952; 
     Also suitable are the following zeolites: 
     K offretite, as described in EP-A400,961; 
     zeolite R, as described in GB 841,812; 
     zeolite LZ-217, as described in U.S. Pat. No. 4,503,023; 
     Ca-free zeolite LZ-218, as described in U.S. Pat. No. 4,333,859; 
     zeolite T, zeolite LZ-220, as described in U.S. Pat. No. 4,503,023; 
     Na 3 K 6 Al 9 Si 27 O 72 .21 H 2 O [zeolite L]; 
     zeolite LZ-211, as described in U.S. Pat. No. 4,503,023; 
     zeolite LZ-212, as described in U.S. Pat. No. 4,503,023; 
     zeolite O, zeolite LZ-217, as described in U.S. Pat. No. 4,503,023; 
     zeolite LZ-219, as described in U.S. Pat. No. 4,503,023; 
     zeolite Rho, zeolite LZ-214, as described in U.S. Pat. No. 4,503,023; 
     zeolite ZK-19, as described in Am. Mineral. 54 1607 (1969); 
     zeolite W (K-M), as described in Barrer et al., J. Chem. Soc. 1956, 2882, 
     Na 30 Al 30 Si66O 192 .98 H 2 O [zeolite ZK-5, zeolite Q] 
     Particular preference is given to zeolite P grades of the formula I in which x is from 2 to 5 and y is from 3.5 to 10, and very particular preference is given to zeolite MAP of the formula I in which x is 2 and y is from 3.5 to 10. In particular, the zeolite concerned is zeolite Na-P, i.e. M is Na. This zeolite generally occurs in the variants Na-P-1, Na-P-2 and Na-P-3, which differ in their cubic, tetragonal or orthorhombic structure (R. M. Barrer, B. M. Munday, J. Chem. Soc. A 1971, 2909-14). The literature reference just referred to also describes the preparation of zeolite P-1 and P-2. According to that reference, zeolite P-3 is very rare and is therefore of virtually no practical interest. The structure of the zeolite P-1 corresponds to the gismondite structure known from the abovementioned Atlas of Zeolite Structures. In recent literature (EP-A-384 070) a distinction is made between cubic (zeolite B or P c ) and tetragonal (zeolite P 1 ) zeolites of the P type. Also mentioned therein are relatively new zeolites of the P type having Si: Al ratios below 1.07:1. These are zeolites having the designation MAP or MA-P, for “Maximum Aluminum P”. Depending on the preparation process, zeolite P may also include small fractions of other zeolites. Highly pure zeolite P has been described in WO 94/26662. Within the scope of the invention it is also possible to use those finely divided, water-insoluble sodium aluminosilicates which have been precipitated and crystallized in the presence of water-soluble organic or inorganic dispersants. These can be introduced into the reaction mixture in any desired manner, prior to or during the precipitation and crystallization. Very particular preference is given to Na zeolite A and Na zeolite P. The hydrotalcites and/or zeolites can be employed in amounts, for example, from 0.1 to 20, judiciously from 0.1 to 10 and, in particular, from 0.1 to 5 parts by weight per 100 parts by weight of halogen-containing polymer. 
     Further customary additives can also be added to the compositions of the invention, such as stabilizers, auxiliaries and processing aids, examples being alkali metal compounds and alkaline earth metal compounds, lubricants, plasticizers, pigments, fillers, phosphites, thiophosphites, β-diketones, β-keto esters, sterically hindered amines and thiophosphates, mercaptocarboxylic esters, epoxidized fatty acid esters, antioxidants, UV absorbers and light stabilizers, optical brighteners, impact modifiers and processing aids, gelling agents, antistats, biocides, metal passivators, flame retardants and blowing agents, antifog agents, compatibilizers and antiplateout agents. (cf. “Handbook of PVC Formulating” by E. J. Wickson, John Wiley &amp; Sons, New York 1993). Examples of such additives are as follows: 
     I. Fillers 
     Fillers (HANDBOOK OF PVC FORMULATING E. J. Wickson, John Wiley &amp; Sons, Inc., 1993, pp. 393-449) and reinforcing agents (TASCHENBUCH der KUNSTSTOFFADDITIVE, R. Gächter &amp; H. Müller, Carl Hanser, 1990, pp. 549-615) are, for example, calcium carbonate, dolomite, wollastonite, magnesium oxide, magnesium hydroxide, silicates, china clay, talc, glass fibers, glass beads, wood flour, mica, metal oxides, or metal hydroxides, carbon black, graphite, rock flour, heavy spar, glass fibers, talc, kaolin and chalk. Chalk is preferred. The fillers can be employed in an amount of preferably at least 1 part, for example, from 5 to 200, judiciously from 10 to 150 and, in particular, from 15 to 100 parts by weight per 100 parts by weight of PVC. 
     II. Metal Soaps 
     Metal soaps are primarily metal carboxylates of preferably relatively long-chain carboxylic acids. Familiar examples are stearates and laurates, and also oleates and salts of shorter-chain alkanecarboxylic acids. Alkylbenzoic acids are also said to be included under metal soaps. Metals which may be mentioned are Li, Na, K, Mg, Ca, Sr, Ba, Zn, Al, La, Ce and rare earth metals. Use is often made of what are known as synergistic mixtures, such as barium/zinc, magnesium/zinc, calcium/zinc or calcium/magnesium/zinc stabilizers. The metal soaps can be employed individually or in mixtures. A review of common metal soaps is given in Ullmann&#39;s Encyclopedia of Industrial Chemistry, 5th Ed., Vol. A16 (1985), p. 361 ff.). It is judicious to use organic metal soaps from the series of the aliphatic saturated C 2 -C 22  carboxylates, the aliphatic unsaturated C 3 -C 22  carboxylates, the aliphatic C 2 -C 22  carboxylates substituted by at least one OH group, the cyclic and bicyclic carboxylates having 5-22 carbon atoms, the unsubstituted benzenecarboxylates substituted by at least one OH group and/or by C 1 -C 16 -alkyl, the unsubstituted naphthalenecarboxylates substituted by at least one OH group and/or by C 1 -C 6 -alkyl, the phenyl C 1 -C 16 -alkylcarboxylates, the naphthyl C 1 -C 16 -alkylcarboxylates or the unsubstituted or C 1 -C 12 -alkyl-substituted phenolates, tallates and resinates. 
     Named examples which may be mentioned are the zinc, calcium, magnesium or barium salts of monovalent carboxylic acids such as acetic, propionic, butyric, valeric, hexanoic, enanthic, octanoic, neodecanoic, 2-ethylhexanoic, pelargonic, decanoic, undecanoic, dodecanoic, tridecanoic, myristic, palmitic, isostearic, stearic, 12-hydroxystearic, behenic, benzoic, p-tert-butylbenzoic, N,N-dimethylhydroxybenzoic, 3,5di-tert-butyl-4-hydroxybenzoic, toluic, dimethylbenzoic, ethylbenzoic, n-propylbenzoic, salicylic, p-tert-octylsalicylic and sorbic acid; calcium, magnesium and zinc salts of the monoesters of divalent carboxylic acids such as oxalic, malonic, succinic, glutaric, adipic, fumaric, pentane-1,5-dicarboxylic, hexane-1,6-dicarboxylic, heptane-1,7-dicarboxylic, octane-1,8-dicarboxylic, phthalic, isophthalic, terephthalic and hydroxyphthalic acid; and of the di- or triesters of tri- or tetravalent carboxylic acids such as hemimellitic, trimellitic, pyromellitic and citric acid. 
     Preference is given to calcium, magnesium and zinc carboxylates of carboxylic acids having 7 to 18 carbon atoms (metal soaps in the narrow sense), such as, for example, benzoates or alkanoates, preferably stearate, oleate, laurate, palmitate, behenate, hydroxystearates, ricinoleates, dihydroxystearates or 2-ethylhexanoate. Particular preference is given to stearate, oleate and p-tert-butylbenzoate. Overbased carboxylates, such as overbased zinc octoate, are also preferred. Preference is likewise given to overbased calcium soaps. If desired, it is also possible to employ a mixture of carboxylates of different structures. 
     Preference is given to compositions, as described, comprising an organozinc and/or organocalcium compound. 
     In addition to the compounds mentioned, organoaluminum compounds are also suitable, as are compounds analogous to those mentioned above, especially aluminum tristearate, aluminum distearate and aluminum monostearate, and also aluminum acetate and basic derivatives derived therefrom. 
     Further information on the aluminum compounds which can be used and are preferred is given in U.S. Pat. No. 4,060,512 and U.S. Pat. No. 3,243,394. 
     Also suitable in addition to the compounds already mentioned are organic rare earth compounds, especially compounds analogous to those mentioned above. The term rare earth compound means especially compounds of the elements cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, lanthanum and yttrium, mixtures—especially with cerium—being preferred. Further preferred rare earth compounds can be found in EP-A-0 108 023. 
     It is possible if desired to employ a mixture of zinc, alkali metal, alkaline earth metal, aluminum, cerium, lanthanum or lanthanoid compounds of different structure. It is also possible for organozinc, organoaluminum, organocerium, organo-alkali metal, organo-alkaline earth metal, organolanthanum or organolanthanoid compounds to be coated on an alumo salt compound; in this regard see also DE-A-4 031 818. 
     The metal soaps and/or mixtures thereof can be employed in an amount of, for example, from 0.001 to 10 parts by weight, judiciously from 0.01 to 8 parts and, with particular preference, from 0.05 to 5 parts by weight per 100 parts by weight of PVC. The same applies to the further metal stabilizers: 
     III. Further Metal Stabilizers 
     Here, mention may be made in particular of the organotin stabilizers. These can be the carboxylates, mercaptides and sulfides, in particular. Examples of suitable compounds are described in U.S. Pat. No. 4,743,640. 
     IV. Alkali Metal and Alkaline Earth Metal Compounds 
     By these are meant principally the carboxylates of the above-described acids, but also corresponding oxides and/or hydroxides or carbonates. Also suitable are mixtures thereof with organic acids. Examples are LiOH, NaOH, KOH, CaO, Ca(OH 2 ), MgO, Mg(OH) 2 , Sr(OH) 2 , Al(OH) 3 , CaCO 3  and MgCO 3  (also basic carbonates, such as magnesia alba and huntite), and also Na and K salts of fatty acids. In the case of alkaline earth metal and Zn carboxylates it is also possible to employ their adducts with MO or M(OH) 2  (M=Ca, Mg, Sr or Zn), known as “overbased” compounds. In addition to the stabilizer combination of the invention it is preferred to employ alkali metal carboxylates, alkaline earth metal carboxylates and/or aluminum carboxylates. 
     V. Lubricants 
     Examples of suitable lubricants are montan wax, fatty acid esters, PE waxes, amide waxes, chlorinated paraffins, glycerol esters or alkaline earth metal soaps. Lubricants which can be used are also described in “Kunststoffadditive”, R. Gächter/H. Müller, Carl Hanser Verlag, 3rd Ed., 1989, pages 478-488. Mention may also be made of fatty ketones (as described in DE 4 204 887) and of silicone-based lubricants (as described in EP 0 225 261) or combinations thereof, as set out in EP 0 259 783. Calcium stearate is preferred. The lubricants can also be applied to an alumo salt compound; in this regard see also DE-A-4 031 818. 
     VI. Plasticizers 
     Examples of suitable organic plasticizers are those from the following groups: 
     A) Phthalates: examples of such plasticizers are dimethyl, diethyl, dibutyl, dihexyl, di-2-ethylhexyl, di-n-octyl, diisooctyl, diisononyl, diisodecyl, diisotridecyl, dicyclohexyl, dimethylcyclohexyl, dimethylglycol, dibutylglycol, benzyl butyl and diphenyl phthalate, and also mixtures of phthalates, such as C 7 -C 9  - and C 9 -C 11 -alkyl phthalates obtained from predominantly linear alcohols, C 6 -C 10 -n-alkyl phthalates and C 8 -C 10 -n-alkyl phthalates. Of these preference is given to dibutyl, dihexyl, di-2-ethylhexyl, di-n-octyl, diisooctyl, diisononyl, diisodecyl, diisotridecyl and benzyl butyl phthalate, and the stated mixtures of alkyl phthalates. Particular preference is given to di-2-ethylhexyl, diisononyl and diisodecyl phthalate, which are also known by the common abbreviations DOP (dioctyl phthalate, di-2-ethylhexyl phthalate), DINP (diisononyl phthalate) and DIDP (diisodecyl phthalate). 
     B) Esters of aliphatic dicarboxylic acids, especially esters of adipic, azelaic and sebacic acid: examples of such plasticizers are di-2-ethylhexyl adipate, diisooctyl adipate (mixture), diisononyl adipate (mixture), diisodecyl adipate (mixture), benzyl butyl adipate, benzyl octyl adipate, di-2-ethylhexyl azelate, di-2-ethylhexyl sebacate and diisodecyl sebacate (mixture). Di-2-ethylhexyl adipate and diisooctyl adipate are preferred. 
     C) Trimellitates, examples being tri-2-ethylhexyl trimellitate, triisodecyl trimellitate (mixture), triisotridecyl trimellitate, triisooctyl trimellitate (mixture) and also tri-C 6 -C 8 -alkyl, tri-C 6 -C 10 -alkyl, tri-C 7 -C 9 -alkyl- and tri-C 9 -C 11 -alkyl trimellitates. The latter trimellitates are formed by esterification of trimellitic acid with the corresponding alkanol mixtures. Preferred trimellitates are tri-2-ethylhexyl trimellitate and the abovementioned trimellitates from alkanol mixtures. Customary abbreviations are TOTM (trioctyl trimellitate, tri-2-ethylhexyl trimellitate), TIDTM (triisodecyl trimellitate) and TITDTM (triisotridecyl trimellitate). 
     D) Epoxy plasticizers: these are primarily epoxidized unsaturated fatty acids, such as epoxidized soybean oil. 
     E) Polymer plasticizers: a definition of these plasticizers and examples of them are given in “Kunststoffadditive”, R. Gächter/H. Müller, Carl Hanser Verlag, 3rd ed., 1989, section 5.9.6, pages 412-415, and also in “PVC Technology”, W. V. Titow, 4th ed., Elsevier Publ., 1984, pages 165-170. The most common starting materials for preparing the polyester plasticizers are dicarboxylic acids, such as adipic, phthalic, azelaic and sebacic acids; diols, such as 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol and diethylene glycol. 
     F) Phosphoric esters: a definition of these esters is given in the abovementioned “Taschenbuch der Kunststoffadditive” section 5.9.5, pp. 408-412. Examples of such phosphoric esters are tributyl phosphate, tri-2-ethylbutyl phosphate, tri-2-ethylhexyl phosphate, trichloroethyl phosphate, 2-ethylhexyl diphenyl phosphate, cresyl diphenyl phosphate, triphenyl phosphate, tricresyl phosphate and trixylenyl phosphate. Preference is given to tri-2-ethylhexyl phosphate and to ®Reofos 50 and 95 (Ciba Spezialitätenchemie). 
     G) Chlorinated hydrocarbons (paraffins) 
     H) Hydrocarbons 
     I) Monoesters, e.g., butyl oleate, phenoxyethyl oleate, tetrahydrofurfuryl oleate and alkylsulfonic esters. 
     J) Glycol esters, e.g., diglycol benzoates. 
     Definitions and examples of plasticizers of groups G) to J) are given in the following handbooks: 
     “Kunststoffadditive”, R. Gächter/H. Müller, Carl Hanser Verlag, 3rd ed., 1989, section 5.9.14.2, pp. 422-425, (group G), and section 5.9.14.1, p. 422, (group H). 
     “PVC Technology”, W. V. Titow, 4th ed., Elsevier Publishers, 1984, section 6.10.2, pages 171-173, (group G), section 6.10.5 page 174, (group H), section 6.10.3, page 173, (group 1) and section 6.10.4, pages 173-174 (group J). 
     It is also possible to use mixtures of different plasticizers. The plasticizers can be employed in an amount of, for example, from 5 to 20 parts by weight, judiciously from 10 to 20 parts by weight, per 100 parts by weight of PVC. Rigid or semirigid PVC contains preferably up to 10%, with particular preference up to 5%, or no plasticizer. 
     VII. Pigments 
     Suitable substances are known to the person skilled in the art. Examples of inorganic pigments are TiO 2 , zirconium oxide-based pigments, BaSO 4 , zinc oxide (zinc white) and lithopones (zinc sulfide/barium sulfate), carbon black, carbon black/titanium dioxide mixtures, iron oxide pigments, Sb 2 O 3 , (Ti,Ba,Sb)O 2 , Cr 2 O 3 , spinels, such as cobalt blue and cobalt green, Cd(S,Se), ultramarine blue. Organic pigments are, for example, azo pigments, phthalocyanine pigments, quinacridone pigments, perylene pigments, diketopyrrolopyrrole pigments and anthraquinone pigments. Preference is also given to TiO 2  in micronized form. A definition and further descriptions are given in “Handbook of PVC Formulating”, E. J. Wickson, John Wiley &amp; Sons, New York, 1993. 
     VIII. Phosphites (Phosphorous Triesters) 
     Examples are triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phosphite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bisisodecyloxypentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl) pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite, bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite. Particularly suitable are trioctyl, tridecyl, tridodecyl, tritetradecyl, tristearyl, trioleyl, triphenyl, tricresyl, tris-p-nonylphenyl or tricyclohexyl phosphite and, with particular preference, the aryl dialkyl and alkyl diaryl phosphites, examples being phenyl didecyl, 2,4-di-tert-butylphenyl didodecyl phosphite, 2,6-di-tert-butylphenyl didodecyl phosphite and the dialkyl and diaryl pentaerythritol diphosphites, such as distearyl pentaerythritol diphosphite, and also nonstoichiometric triaryl phosphites whose composition is, for example, (H 19 C 9 -C 6 H 4 )O 1.5 P(OC 12,13 H 25,27 ) 1.5  or (H 8 C 17 -C 6 H 4 )O 2 P(i-C 8 H 17 O) or (H 19 C 9 -C 6 H 4 )O 1.5 P(OC 9,11 H 19,23 ) 1,5  or                    
     Preferred organic phosphites are distearyl pentaerythritol diphosphite, trisnonylphenyl phosphite and phenyl didecyl phosphite. Other suitable phosphites are phosphorous diesters (with abovementioned radicals) and phosphorous monoesters (with abovementioned radicals), possibly in the form of their alkali metal, alkaline earth metal, zinc or aluminum salts. It is also possible for these phosphorous esters to have been applied to an alumo salt compound; in this regard see also DE-A-4 031 818. 
     The organic phosphites can be employed in an amount of, for example, from 0.01 to 10, judiciously from 0.05 to 5 and, in particular, from 0.1 to 3 parts by weight per 100 parts by weight of PVC. 
     IX. Thiophosphites and Thiophosphates 
     By thiophosphites and thiophosphates are meant compounds of the general type (RS) 3 P, (RS) 3 P═O and (RS) 3 P═S, respectively, as are described, for instance, in the patents DE 2 809 492, EP 0 090 770 and EP 0 573 394. Examples of these compounds are trithiohexyl phosphite, trithiooctyl phosphite, trithiolauryl phosphite, trithiobenzyl phosphite, trithiophosphorous acid tris(carbo-i-octyl-oxy)methyl ester, trithiophosphorous acid tris(carbotrimethylcyclohexyloxy)-methyl ester, trithiophosphoric acid S,S,S-tris(carbo-i-octyloxy)methyl ester, trithiophosphoric acid S,S,S-tris(carbo-2-ethylhexyloxy)methyl ester, trithio-phosphoric acid S,S,S-tris-1-(carbohexyloxy)ethyl ester, trithiophosphoric acid S,S,S-tris-1-(carbo-2-ethylhexyloxy)ethyl ester and trithiophosphoric acid S,S,S-tris-2-(carbo-2-ethylhexyloxy)ethyl ester. 
     X. Mercaptocarboxylic Esters 
     Examples of these compounds are esters of thioglycolic acid, thiomalic acid, mercaptopropionic acid, the mercaptobenzoic acids and thiolactic acid, mercaptoethyl stearate and mercaptoethyl oleate, as are described in patents FR 2 459 816, EP 0 090 748, FR 2 552 440 and EP 0 365 483. The generic mercaptocarboxylic esters also embrace polyol esters and partial esters thereof, and also thioethers derived from them. 
     XI. Epoxidized Fatty Acid Esters and Other Epoxy Compounds 
     The stabilizer combination of the invention may additionally comprise preferably at least one epoxidized fatty acid ester. Particularly suitable such esters are those of fatty acids from natural sources (fatty acid glycerides), such as soybean oil or rapeseed oil. It is, however, also possible to employ synthetic products such as epoxidized butyl oleate. Epoxidized polybutadiene and polyisoprene can also be used, as they are or in partially hydroxylated form, or else homo- or copolymeric glycidyl acrylate and glycidyl methacrylate can be used. These epoxy compounds can also have been applied to an alumo salt compound; in this regard see also DE-A4 031 818. 
     XII. Antioxidants 
     Examples of suitable such compounds are: 
     Alkylated monophenols, for example, 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-iso-butylphenol, 2,6-di-cyclopentyl-4-methylphenol, 2-(alpha-methylcyclohexyl)4,6-dimethylphenol, 2,6-di-octa-decyl-4-methylphenol, 2,4,6-tricyclohexyl phenol, 2,6-di-tert-butyl-4-methoxy-methylphenol, 2,6-dinonyl-4-methylphenol, 2,4-dimethyl-6-(1′-methylundec-1′-yl)phenol, 2,4-dimethyl-6-(1′-methylheptadec-1′-yl)phenol, 2,4-dimethyl-6-(1′-methyltridec-1′-yl)phenol, octylphenol, nonylphenol, dodecylphenol and mixtures thereof. 
     Alkylthiomethylphenols, for example, 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioctylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-didodecylthiomethyl-4-nonylphenol. 
     Alkylated hydroquinones, for example, 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis(3,5-di-tert-butyl-4-hydroxyphenyl) adipate. 
     Hydroxylated thiodiphenyl ethers, for example, 2,2′-thiobis(6-tert-butyl-4-methylphenol), 2,2′-thiobis(4-octylphenol), 4,4′-thiobis(6-tert-butyl-3-methylphenol), 4,4′-thiobis(6-tert-butyl-2-methylphenol), 4,4′-thiobis-(3,6-di-sec-amylphenol), 4,4′-bis(2,6-dimethyl-4-hydroxyphenyl) disulfide. 
     Alkylidenebisphenols for example, 2,2′-methylenebis(6-tert-butyl-4-methylphenol), 2,2′-methylenebis(6-tert-butyl-4-ethylphenol), 2,2′-methylene-bis[4-methyl-6-(alpha-methylcyclohexyl)phenol], 2,2′-methylenebis(4-methyl-6-cyclohexylphenol), 2,2′-methylenebis(6-nonyl-4-methylphenol), 2,2′-methylenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(4,6-di-tert-butylphenol), 2,2′-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2′-methylenebis[6-(alpha-methylbenzyl)-4-nonylphenol], 2,2′-methylenebis[6-(alpha,alpha-dimethylbenzyl)-4-nonylphenol], 4,4′-methylenebis(2,6di-tert-butylphenol), 4,4′-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)4-methylphenol, 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methyl-phenyl)butane, 1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis-(3′-tert-butyl-4′-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadiene, bis[2-(3′-tert-butyl-2′-hydroxy-5′-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephthalate, 1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-phenyl)propane, 2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane, 1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane. 
     Benzyl compounds, for example, 3,5,3′,5′-tetra-tert-butyl-4,4′-dihydroxydibenzyl ether, octadecyl 4-hydroxy-3,5-dimethylbenzyl-mercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl 3,5-di-tert-butyl-4-hydroxybenzyl-mercaptoacetate. 
     Hydroxybenzylated malonates, for example, dioctadecyl 2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate, dioctadecyl 2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate, didodecyl mercaptoethyl-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, di[4-(1,1,3,3-tetramethylbutyl)-phenyl]2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate. 
     Aromatic hydroxybenzyl compounds, for example, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1 ,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol. 
     Triazine compounds for example, 2,4-bisoctylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine, 2-octylmercapto-4,6-bis-(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine, 2,4,6(tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5(tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine, 1,3,5-tris-(3,5-dicyclohexyl-4-hydroxybenzyl) isocyanurate. 
     Phosphonates and phosphonites, for example, dimethyl 2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate, dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl 5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, Ca salt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate, tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylenediphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenz[d,g]-1,3,2-dioxaphosphocine, 6-fluoro-2,4,8,10 -tetra-tert-butyl-12-methyl-dibenz[d,g]-1,3,2-dioxaphosphocine. 
     Acylaminophenols, for example, 4-hydroxylauranilide, 4-hydroxystearanilide, octyl N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate. 
     Esters of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propane diol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, dipentaerythritol, tris(hydroxyethyl) isocyanurate, N,N′-bis-(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, ditrimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
     Esters of beta-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with mono- or polyhydric alcohols, for example, with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxy)ethyl isocyanurate, N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
     Esters of beta-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, for example, with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxy)ethyl isocyanurate, N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
     Esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid with mono- or polyhydric alcohols, for example, with methanol, ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxy)ethyl isocyanurate, N,N′-bis(hydroxyethyl)oxalamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane. 
     Amides of beta-(3,5-di-tert-butyl-4-hydroxyhenyl)propionic acid, such as, for example, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine, N,N′-bis(3,5di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine, N,N′-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine. 
     Vitamin E (tocopherol) and derivatives. 
     Preference is given to antioxidants of groups 1-5, 10 and 12, especially 2,2-bis(4-hydroxyphenyl)propane, esters of 3,5di-tert-butyl-4-hydroxyphenylpropionic acid with octanol, octadecanol or pentaerythritol or tris(2,4-di-tert-butylphenyl) phosphite. 
     It is also possible, if desired, to employ a mixture of antioxidants of different structures. 
     The antioxidants can be employed in an amount of, for example, from 0.01 to 10 parts by weight, judiciously from 0.1 to 10 parts by weight and in particular, from 0.1 to 5 parts by weight per 100 parts by weight of PVC. 
     XIII. UV Absorbers and Light Stabilizers 
     Examples of these are: 
     2-(2′-Hydroxyphenyl)benzotriazoles, such as, for example 2-(2′-hydroxy-5′-methylphenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole, 2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxyphenyl)benzotriazole, 2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole, 2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole, 2-(3′,5′-bis(alpha,alpha-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, mixtures of 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole, 2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole, 2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole and 2-(3′-tert-butyl-2′-hydroxy-5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol]; the transesterification product of 2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]benzotriazole with polyethylene glycol 300; where R=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-yl-phenyl. 
     2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy, 2′-hydroxy-4,4′-dimethoxy derivative. 
     Esters of substituted or unsubstituted benzoic acids, for example 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxy-benzoate. 
     Acrylates, for example ethyl alpha-cyano-beta,beta-diphenylacrylate or isooctyl-ethyl alpha-cyano-beta,beta-diphenylacrylate, methyl alpha-carbomethoxycinnamate, methyl alpha-cyano-beta-methyl-p-methoxycinnamate or butyl alpha-cyano-beta-methyl-p-methoxycinnamate, methyl alpha-carbomethoxy-p-methoxycinnamate, N-(beta-carbomethoxy-b-cyanovinyl)2-methylindoline. 
     Nickel compounds, for example nickel complexes of 2,2′-thiobis[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyidiethanolamine, nickel dibutyidithiocarbamate, nickel salts of monoalkyl esters such as the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes of ketoximes, such as of 2-hydroxy-4-methylphenyl undecyl ketoxime, nickel complexes of 1-phenyl4-lauroyl-5-hydroxypyrazole, with or without additional ligands. 
     Oxalamides, for example 4,4′-dioctyloxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butyl-oxanilide, 2,2′-didodecyloxy-5,5′-di-tert-butyloxanilide, 2-ethoxy-2′-ethyl-oxanilide, N,N′-bis(3-dimethylaminopropyl)oxalamide, 2-ethoxy-5-tert-butyl-2′-ethyloxanilide and its mixture with 2-ethoxy-2′-ethyl-5,4′-di-tert-butyl-oxanilide, mixtures of o- and p-methoxy and of o- and p-ethoxy-di-substituted oxanilides. 
     2-(2-Hydroxyphenyl)1,3,5-triazines, for example 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropyloxy)phenyl]-4,6-bis-(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine. 
     Sterically hindered amines, for example bis(2,2,6,6-tetramethyl-piperidin-4-yl) sebacate, bis(2,2,6,6-tetramethylpiperidin-4-yl) succinate, bis(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, bis(1,2,2,6,6-pentamethylpiperidyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic condensates of N,N′-bis(2,2,6,6-tetramethyl4-piperidyl)hexamethylenediamine and 4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate, tetrakis(2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetraoate, 1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1,2,2,6,6-pentamethylpiperidyl) 2-n-butyl-2-(2-hydroxy-3,5di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, linear or cyclic condensates of N,N′-bis(2,2,6,6-tetramethyl4-piperidyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1,3,5-triazine, the condensate of 2-chloro4,6-di-(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazine und 1,2-bis(3-aminopropylamino)ethane, the condensate of 2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazine and 1,2-bis(3-aminopropylamino)ethane, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1-(2,2,6,6-tetramethylpiperidyl)pyrrolidine-2,5-dione, 3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione, mixtures of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, the condensate of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylendiamine and 4-cyclohexylamino-2,6-dichloro-1,3,5-triazine, the condensate of 1,2-bis(3-aminopropylamino)ethane and 2,4,6-trichloro-1,3,5-triazine, and also 4-butylamino-2,2,6,6-tetramethylpiperidine (CAS Reg. No. [136504-96-6]); N-(2,2,6,6-tetramethyl4-piperidyl)-n-dodecylsuccinimide, N-(1,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimide, 2-undecyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza4-oxo-spiro[4.5]decane, the reaction product of 7,7,9,9-tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza4-oxospiro[4.5]decane and epichlorohydrin, 1,1-bis(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene, N, N′-bisformyl-N,N′-bis(2,2,6,6-tetramethyl4-piperidyl)hexamethylenediamine, the diester of 4-methoxymethylenemalonic acid with 1,2,2,6,6-pentamethyl-4-hydroxypiperidine, poly[methylpropyl-3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, the reaction product of maleic anhydride-α-olefin copolymer and 2,2,6,6-tetramethyl4-aminopiperidine or 1,2,2,6,6-pentamethyl4-aminopiperidine. 
     XIV. Blowing Agents 
     Examples of blowing agents are organic azo and hydrazo compounds, tetrazoles, oxazines, isatoic anhydride, and also sodium carbonate and sodium bicarbonate. Preference is given to azodicarboxamide and sodium bicarbonate and mixtures thereof. 
     Definitions and examples of impact modifiers and processing aids, gelling agents, antistats, biocides, metal passivators, optical brighteners, flame retardants, antifogging agents and compatibilizers are described in “Kunststoffadditive”, R. Gächter/H. Müller, Carl Hanser Verlag, 3rd ed., 1989, and in the “Handbook of Polyvinyl Chloride Formulating” E. J. Wickson, J. Wiley &amp; Sons, 1993, and in “Plastics Additives” G. Pritchard, Chapman &amp; Hall, London, 1st ed., 1998. 
     Impact modifiers are also described in detail in “Impact Modifiers for PVC”, J. T. Lutz/D. L. Dunkelberger, John Wiley &amp; Sons, 1992. 
     XV. beta-Diketones, beta-Keto Esters 
     1,3-dicarbonyl compounds which can be used may be linear or cyclic dicarbonyl compounds. Preference is given to the use of dicarbonyl compounds of the following formula: R′ 1 CO CHR′ 2 —COR′ 3  in which R′ 1  is C 1 -C 22 -alkyl, C 5 -C 10 -hydroxyalkyl, C 2 -C 18 -alkenyl, phenyl, OH—, C 1 -C 4 -alkyl-, C 1 -C 4 -alkoxy- or halogen-substituted phenyl, C 7 -C 10 -phenylalkyl, C 5 -C 12 -cycloalkyl, C 1 -C 4 -alkyl-substituted C 5 -C 12 -cycloalkyl or a group —R′ 5 —S—R′ 6  or —R′ 5 —O—R′ 6 , R 2  is hydrogen, C 1 -C 8 -alkyl, C 2 -C 12 -alkenyl, phenyl, C 7 -C 12 -alkylphenyl, C 7 -C 10 -phenylalkyl or a group —CO—R′ 4 , R′ 3  is as defined for R′ 1  or is C 1 -C 18 -alkoxy, R′ 4  is C 1 -C 4 -alkyl or phenyl, R′ 5  is C 1 -C 10 -alkylene and R′ 6  is C 1 -C 12 -alkyl, phenyl, C 7 -C 18 -alkylphenyl or C 7 -C 10 -phenylalkyl. 
     These include the hydroxyl-containing diketones of EP 0 346 279 and the oxa and thia diketones of EP 0 307 358, as well as the keto esters based on isocyanic acid, of U.S. Pat. No. 4,339,383. 
     R′ 1  and R′ 3  as alkyl can in particular be C 1 -C 16 -alkyl, such as, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl or octadecyl. 
     R′ 1  and R′ 3  as hydroxyalkyl are in particular a group —(CH 2 ) n —OH in which n is 5, 6 or7. 
     R′ 1  and R′ 3  as alkenyl can for example be vinyl, allyl, methallyl, 1-butenyl, 1-hexenyl or oleyl, preferably allyl. 
     R′ 1  and R′ 3  as OH-, alkyl-, alkoxy- or halogen-substituted phenyl can for example be tolyl, xylyl, tert-butylphenyl, methoxyphenyl, ethoxyphenyl, hydroxyphenyl, chlorophenyl or dichlorophenyl. 
     R′ 1  and R′ 3  as phenylalkyl are in particular benzyl. R′ 2  and R′ 3  as cycloalkyl or alkylcycloalkyl are, in particular, cyclohexyl or methylcyclohexyl. R′ 2  as alkyl can in particular be C 1 -C 4 -alkyl. R′ 2  as C 2 -C 12 -alkenyl can in particular be allyl. R′ 2  as alkylphenyl can in particular be tolyl. R′ 2  as phenylalkyl can in particular be benzyl. Preferably, R′ 2  is hydrogen. R′ 3  as alkoxy can for example be methoxy, ethoxy, butoxy, hexyloxy, octyloxy, dodecyloxy, tridecyloxy, tetradecyloxy or octadecyloxy. R′ 5  as C 1 -C 10 -alkylene is, in particular, C 2 -C 4 -alkylene. R′ 6  as alkyl is, in particular, C 4 -C 12 -alkyl, such as, for example butyl, hexyl, octyl, decyl or dodecyl. R′ 6  as alkylphenyl is in particular tolyl. R′ 6  as phenylalkyl is in particular benzyl. 
     Examples of 1,3-dicarbonyl compounds of the above formula and their alkali metal, alkaline earth metal, zinc and aluminum chelates are acetylacetone, butanoylacetone, heptanoylacetone, steroylacetone, palmitoylacetone, lauroylacetone, 7-tert-nonylthio-2,4-heptanedione, benzoylacetone, dibenzoylmethane, lauroylbenzoylmethane, palmitoylbenzoylmethane, stearoylbenzoylmethane, isooctylbenzoylmethane, 5-hydroxycapronylbenzoylmethane, tribenzoylmethane, bis(4-methylbenzoyl)methane, benzoyl-p-chlorobenzoylmethane, bis(2-hydroxybenzoyl)methane, 4-methoxybenzoylbenzoylmethane, bis(4-methoxybenzoyl)methane, 1-benzoyl-1-acetylnonane, benzoylacetylphenylmethane, stearoyl4-methoxybenzoylmethane, bis(4-tert-butylbenzoyl)methane, benzoylformylmethane, benzoylphenylacetylmethane, biscyclohexanoylmethane, di-pivaloylmethane, 2-acetylcyclopentanone, 2-benzoylcyclopentanone, methyl, ethyl and allyl diacetoacetate, methyl and ethyl benzoyl-, propionyl- and butyrylacetoacetate, triacetylmethane, methyl, ethyl, hexyl, octyl, dodecyl or octadecyl acetoacetate, methyl, ethyl, butyl, 2-ethylhexyl, dodecyl or octadecyl benzoylacetate, and also C 1 -C 18 -alkyl propionylacetates and butyrylacetates; ethyl, propyl, butyl, hexyl or octyl stearoylacetate, and also polycyclic β-keto esters, as described in EP 0 433 230, and dehydraacetic acid, and the aluminum, zinc, alkaline earth metal or alkali metal salts thereof. 
     Preference is given to 1,3-diketo compounds of the above formula in which R′ 1  is C 1 -C 18 -alkyl, phenyl, OH-, methyl- or methoxy-substituted phenyl, C 7 -C 10 -phenylalkyl or cyclohexyl, R′ 2  is hydrogen and R′ 3  is as defined for R′ 1 . The 1,3-diketo compounds can be employed in amount of, for example, from 0.01 to 10, judiciously from 0.01 to 3 and, in particular, from 0.01 to 2 parts by weight per 100 parts by weight of PVC. 
     Examples of the chlorine-containing polymers to be stabilized are: polymers of vinyl chloride and of vinylidene chloride, vinyl resins comprising vinyl chloride units in their structure, such as copolymers of vinyl chloride, and vinyl esters of aliphatic acids, especially vinyl acetate, copolymers of vinyl chloride with esters of acrylic and methacrylic acid and with acrylonitrile, copolymers of vinyl chloride with diene compounds and unsaturated dicarboxylic acids or their anhydrides, such as copolymers of vinyl chloride with diethyl maleate, diethyl fumarate or maleic anhydride, post-chlorinated polymers and copolymers of vinyl chloride, copolymers of vinyl chloride and vinylidene chloride with unsaturated aldehydes, ketones and others, such as acrolein, crotonaldehyde, vinyl methyl ketone, vinyl methyl ether, vinyl isobutyl ether and the like; polymers of vinylidene chloride and its copolymers with vinyl chloride and other polymerizable compounds; polymers of vinyl chloroacetate and dichlorodivinyl ether; chlorinated polymers of vinyl acetate, chlorinated polymeric esters of acrylic acid and of alpha-substituted acrylic acid; polymers of chlorinated styrenes, for example dichlorostyrene; chlorinated rubbers; chlorinated polymers of ethylene; polymers and post-chlorinated polymers of chlorobutadiene and copolymers thereof with vinyl chloride, chlorinated natural and synthetic rubbers, and also mixtures of these polymers with one another or with other polymerizable compounds. In the context of this invention, PVC also embraces copolymers with polymerizable compounds such as acrylonitrile, vinyl acetate or ABS, which can be suspension, bulk or emulsion polymers. Preference is given to a PVC homopolymer, alone or in combination with polyacrylates. 
     Also included are graft polymers of PVC with EVA, ABS and MBS. Preferred substrates are also mixtures of the abovementioned homo- and copolymers, especially vinyl chloride homopolymers, with other thermoplastic and/or elastomeric polymers, especially blends with ABS, MBS, NBR, SAN, EVA, CPE, MBAS, PMA, PMMA, EPDM and polylactones. 
     Examples of such components are compositions of (i) 20-80 parts by weight of a vinyl chloride homopolymer (PVC) and (ii) 80-20 parts by weight of at least one thermoplastic copolymer based on styrene and acrylonitrile, in particular from the group ABS, NBR, NAR, SAN and EVA. The abbreviations used for the copolymers are familiar to the person skilled in the art and have the following meanings: ABS: acrylonitrile-butadiene-styrene; SAN: styrene-acrylonitrile; NBR: acrylonitrile-butadiene; NAR: acrylonitrile-acrylate; EVA: ethylene-vinyl acetate. Also suitable in particular are acrylate-based styrene-acrylonitrile copolymers (ASA). Preferred components in this context are polymer compositions comprising as components (i) and (ii) a mixture of 25-75% by weight PVC and 75-25% by weight of the abovementioned copolymers. Examples of such compositions are: 25-50% by weight PVC and 75-50% by weight copolymers or 40-75% by weight PVC and 60-25% by weight copolymers. Preferred copolymers are ABS, SAN and modified EVA, especially ABS. NBR, NAR and EVA are also particularly suitable. In the composition of the invention it is possible for one or more of the abovementioned copolymers to be present. Particularly important components are compositions comprising (i) 100 parts by weight of PVC and (ii) 0-300 parts by weight of ABS and/or SAN-modified ABS and 0-80 parts by weight of the copolymers NBR, NAR and/or EVA, but especially EVA. 
     For stabilization in the context of this invention, further suitable polymers are, in particular, recyclates of chlorine-containing polymers, these polymers being the polymers described in more detail above that have also undergone damage through processing, use or storage. PVC recyclate is particularly preferred. The recyclates may also include small amounts of extraneous substances, such as, for example, paper, pigments, adhesives, which are often difficult to remove. These extraneous substances may also arise from contact with various materials in the course of use or reprocessing, examples being residues of fuel, fractions of coating material, traces of metal and residues of initiator. 
     Stabilization in accordance with the invention is of particular advantage in the context of PVC formulations as are customary for pipes and profiles. Stabilization can be effected without heavy metal compounds (Sn, Pb, Cd, Zn stabilizers). This characteristic offers advantages in certain fields, since heavy metals—with the exception of zinc at best—are often unwanted both during the production and during the use of certain PVC articles, on ecological grounds. The production of heavy metal stabilizers also often causes problems from an industrial hygiene standpoint. Similarly, the processing of ores containing heavy metals is frequently associated with serious effects on the environment, the environment here including the biosystem of humankind, animals (fish), plants, the air and soil. For these reasons, the incineration and landfilling of plastics containing heavy metals is also disputed. 
     The invention also relates to a method of stabilizing PVC, which comprises adding thereto at least one of the abovementioned stabilizer combinations. 
     The stabilizers can judiciously be incorporated by the following methods: as an emulsion or dispersion (one possibility, for example, is the form of a pastelike mixture. An advantage of the combination of the invention in the case of this form is the stability of the paste.); as a dry mix in the course of the mixing of additional components or polymer mixtures; by direct addition to the processing apparatus (e.g. calenders, mixers, compounders, extruders and the like), or as a solution or melt. 
     The PVC stabilized in accordance with the invention, to which the invention likewise relates, can be prepared in a manner known per se using devices known per se such as the abovementioned processing apparatus to mix the stabilizer combination of the invention and any further additives with the PVC. In this case, the stabilizers can be added individually or as a mixture or else in the form of so-called masterbatches. 
     The PVC stabilized in accordance with the present invention can be brought into the desired form by known methods. Examples of such methods are milling, calendering, extruding, injection molding or spinning, and also extrusion blow molding. The stabilized PVC can also be processed to foam materials. 
     A PVC stabilized in accordance with the invention is suitable, for example, for hollow articles (bottles), packaging films (thermoform sheets), blown films, pipes, foam materials, heavy profiles (window frames), transparent-wall profiles, construction profiles, sidings, fittings, office films and apparatus enclosures (computers, domestic appliances) as well as panels. Preference is given to PVC rigid foam articles and PVC pipes for drinking water or wastewater, pressure pipes, gas pipes, cable-duct pipes and cable protection pipes, pipes for industrial pipelines, seepage pipes, flowoff pipes, guttering pipes and drainage pipes. For further details on this subject see “Kunststoffhandbuch PVC”, Vol. 2/2, W. Becker/H. Braun, 2nd ed., 1985, Carl Hanser Verlag, pages 1236-1277. 
     The compounds of the formula I are prepared by known methods [U.S. Pat. No. 2,598,936 and J. Org. Chem. 16, 1879-1890 (1951)], as explained in more detail in the following Examples 1 to 3. Here, as in the remainder of the text, parts and percentages are by weight unless stated otherwise. 
    
    
     EXAMPLE 1 
     Cyanoacetyldibenzylurea 
     
       
         
         
             
             
         
       
     
     36.0 g (0.15 mol) of dibenzylurea, 15.3 g (0.18 mol) of cyanoacetic acid and 30.6 g (0.3 mol) of acetic anhydride are stirred at 80-85° C. for 2 hours. After cooling, the reaction mixture is stirred into 600 ml of water and the resultant precipitate is filtered off with suction and then dried to constant weight. 
     Yield: 44.7 g (=96.9% of theory) 
     For purification, the crude product is recrystallized from 150 ml of n-propanol. This gives white crystals having a melting point of 86-87° C. 
     EXAMPLE 2 
     Cyanoacetyldibenzylurea 
     
       
         
         
             
             
         
       
     
     Cyanoacetyldimethylurea is prepared in analogy to Example 1. Instead of dibenzylurea, dimethylurea is employed. The product is worked up by stripping off the acetic anhydride/acetic acid mixture on a rotary evaporator under reduced pressure. The residue obtained in this way is recrystallized from water. 
     Yield: 90% of theory, white crystals with a melting point of 75-76° C. 
     EXAMPLE 3 
     N-Cyanoacetyl-N-benzyl-N′-2-acetoxyethylurea/N′-Cyanoacetyl-N′-2-acetoxyethyl-N-benzylurea 
     
       
         
         
             
             
         
       
     
     In analogy to Example 1 Example 3 is prepared. Instead of N,N′-dibenzylurea the acetylated N′-(2-hydroxyethyl)-N-benzylurea is employed. The crude product is worked up by distilling off the acetic anhydride/acetic acid mixture to leave a residue. The residue is dissolved in dichloromethane. The organic solution is washed with water and sodium hydrogen carbonate solution, dried over sodium sulfate and concentrated on a rotary evaporator to give a further residue. 
     Yield: 96.7% of theory, viscous, honey-colored liquid 
     According to  1 H-NMR the distribution is as follows: 
     
       
         
           
               
               
             
               
                   
               
             
            
               
                 55.4 mol% 
                 of the compound 0 
               
               
                 37.6 mol% 
                 of the compound 02, and 
               
               
                  6.9 mol% 
                 of initial urea 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 4 
     Static Heat Test 
     A dry mixture consisting of 
     
       
         
           
               
               
               
             
               
                   
               
             
            
               
                 100.0 
                 parts 
                 of Evipol SH 5730 = PVC K value 57 
               
               
                 5.0 
                 parts 
                 of BTA III N 2 = MBS modifier 
               
               
                 0.5 
                 part 
                 of Paraloid K 120 N = acrylate processing aid 
               
               
                 0.5 
                 part 
                 of Paraloid K 175 = acrylate processing aid 
               
               
                 0.3 
                 part 
                 of wax E = esterwax (Montan wax) 
               
               
                 3.0 
                 parts 
                 of ESO = epoxidized soybean oil 
               
               
                 1.0 
                 parts 
                 of Loxiol G 16 = fatty acid partial ester of glycerol 
               
               
                   
               
            
           
         
       
     
     and in each case one of the stabilizers indicated in Tables 1a) and 1b) is rolled on a set of mixing rolls at 180° C. for five minutes. Test film pieces 0.3 mm thick are taken from the resultant rolled sheet. The film samples are subjected to thermal stress at 190° C. in an oven. The Yellowness Index (YI) in accordance with ASTM D-1 925-70 is determined at intervals of 3 minutes. The results can be taken from Table 1 [a) and b)] below. Low YI values denote good stabilization. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1a) 
               
               
                   
               
               
                   
                 Mixture A 
                 Mixture B 
                 Mixture C 
               
               
                   
                 Ca stearate 0.8 
                 Stabilizer 1 
                 Stabilizer 1 1.0 part 
               
               
                   
                 part Malbit CH 
                 1.0 part Manomet 
                 Ca stearate 0.8 part 
               
               
                 Minutes 
                 16385 0.4 part 
                 200 0.8 part 
                 Malbit CH 16385 0.4 part 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0 
                 YI 
                 61.63 
                 YI 
                 15.89 
                 YI 
                 15.13 
               
               
                 3 
                   
                 64.89 
                   
                 16.23 
                   
                 16.53 
               
               
                 6 
                   
                 78.37 
                   
                 19.24 
                   
                 19.52 
               
               
                 9 
                   
                 107.90 
                   
                 24.51 
                   
                 25.51 
               
               
                 12 
                   
                 145.69 
                   
                 31.33 
                   
                 32.55 
               
               
                 15 
                   
                   
                   
                 38.05 
                   
                 43.45 
               
               
                 18 
                   
                   
                   
                 46.43 
                   
                 61.94 
               
               
                 21 
                   
                   
                   
                 61.37 
                   
                 86.83 
               
               
                 24 
                   
                   
                   
                 81.30 
                   
                 108.34 
               
               
                 27 
                   
                   
                   
                 125.65 
                   
                 134.38 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                 TABLE 1b) 
               
               
                   
               
               
                   
                   
                 Mixture E 
                   
               
               
                   
                 Mixture D 
                 Stabilizer 2 
                 Mixture F 
               
               
                   
                 Stabilizer 2 
                 1.0 part Ca 
                 Stabilizer 3 1.0 part 
               
               
                   
                 1.0 part 
                 stearate 0.1 
                 Ca stearate 0.8 part 
               
               
                   
                 Manomet 200 
                 part Malbit CH 
                 Malbit CH 16385 
               
               
                 Minutes 
                 0.8 part 
                 16385 0.1 part 
                 0.4 part 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 0 
                 YI 
                 16.05 
                 YI 
                 12.00 
                 YI 
                 12.48 
               
               
                 3 
                   
                 20.21 
                   
                 21.88 
                   
                 13.97 
               
               
                 6 
                   
                 22.03 
                   
                 25.89 
                   
                 15.55 
               
               
                 9 
                   
                 24.38 
                   
                 27.86 
                   
                 18.21 
               
               
                 12 
                   
                 26.37 
                   
                 27.17 
                   
                 22.37 
               
               
                 15 
                   
                 29.57 
                   
                 32.75 
                   
                 28.67 
               
               
                 18 
                   
                 39.20 
                   
                 39.88 
                   
                 38.79 
               
               
                 21 
                   
                 61.72 
                   
                 52.58 
                   
                 53.48 
               
               
                 24 
                   
                 97.00 
                   
                 71.61 
                   
                 70.38 
               
               
                 27 
                   
                 141.75 
                   
                 103.51 
                   
                 90.33 
               
               
                 30 
                   
                   
                   
                   
                   
                 113.93 
               
               
                 33 
                   
                   
                   
                   
                   
                 141.82 
               
               
                   
               
            
           
         
       
     
     Key to Example 4/Table 1: 
     See table Manomet 200=overbased Ca stearate 
     See table Malbit CH 16385=Maltitol (polyol) 
     See table Stabilizer 1=cyanoacetyidibenzylurea (Example 1) 
     See table Stabilizer 2=cyanoacetyidimethylurea (Example 2) 
     See table Stabilizer 3=N-cyanoacetyl-N-benzyl-N′-2-acetoxyethy/urea/N′-cyanoacetyl-N′-2-acetoxyethyl-N-benzylurea (Example 3) 
     The mixtures of the invention (B to F) exhibit relative to the comparative mixture (A) a drastic improvement in thermal stability in terms of initial color, color attention, and long-term stability. 
     EXAMPLE 5 
     A dry mixture consisting of 
     
       
         
           
               
               
               
             
               
                   
               
             
            
               
                 100.00 
                 parts 
                 of Norvinyl S 6775 = S-PVC 
               
               
                 2.00 
                 parts 
                 of Omyalite 95 T = chalk 
               
               
                 0.80 
                 part 
                 of Ca stearate 
               
               
                 0.70 
                 part 
                 of IRGAWAX 367 = paraffin wax 
               
               
                 0.60 
                 part 
                 of Hoechst-Wachs PE 520 = ester wax (partially 
               
               
                   
                   
                 saponified Montan acid ester) from Hoechst 
               
               
                 0.15 
                 part 
                 of Allied AC 629 A = oxidized homopolymer from 
               
               
                   
                   
                 Allied Signal 
               
               
                 0.05 
                 part 
                 of Allied AC 316 = oxidized polyethylene from Allied 
               
               
                 1.00 
                 part 
                 Signal of Wessalith P = Na-zeolite A 
               
               
                 0.40 
                 part 
                 Malbit CH 16385 = maltitol 
               
               
                 0.20 
                 part 
                 Mark 6045 J = mixture of 9% NaCIO 4 , 45% CaCO 3 , 
               
               
                   
                   
                 40% CaSiO 3 , 6% H 2 O 
               
               
                   
               
            
           
         
       
     
     and the stabilizer indicated in Table 2 is rolled on a set of mixing rolls at 200° C. for 5 minutes. Test film pieces 0.3 mm thick are taken from the resultant rolled sheet. The film samples are subjected to thermal stress at 190° C. in an oven. The Yellowness Index (Yl) in accordance with ASTM D-1925-70 is determined at intervals of 3 minutes. The results can be taken from Tables 1 and 2 below. Low YI values denote good stabilization. 
     
       
         
           
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Mixture G 
                 Mixture H 
               
               
                 Minutes 
                 without further stabilizer 
                 stabilizer 2 0.2 part 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 0 
                 YI 
                 98.18 
                 YI 
                 30.79 
               
               
                 3 
                   
                 100.53 
                   
                 32.35 
               
               
                 6 
                   
                 101.56 
                   
                 35.74 
               
               
                 9 
                   
                 102.21 
                   
                 42.17 
               
               
                 12 
                   
                 103.59 
                   
                 49.78 
               
               
                 15 
                   
                 105.50 
                   
                 59.89 
               
               
                 18 
                   
                 116.70 
                   
                 72.61 
               
               
                 21 
                   
                   
                   
                 83.86 
               
               
                 24 
                   
                   
                   
                 99.09 
               
               
                 27 
                   
                   
                   
                 113.04 
               
               
                   
               
            
           
         
       
     
     Key to Table 2 
     Stabilizer 2=Cyanoacetyidimethylurea (Example 2) 
     The composition of the invention (H) exhibits, relative to the comparative mixture (G), a very good improvement in the stabilizer action both in terms of initial color and color retention and in relation to the long-term stability.