Stabilizing composition for halogen-containing polymers

Abstract

The invention relates to a stabilizing composition comprising DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione) and DHP (3.5- pyridinedicarboxylicacid, i.e. didodecyl-1.4-dihydro-2.6-dimethylpyridin-3.5- dicarboxylate) in certain amounts and a resin comprising said stabilizing composition.

Description

[0001] STABILIZING COMPOSITION FOR HALOGEN-CONTAINING POLYMERS FIELD OF THE INVENTION

[0002] The invention concerns a stabilized halogen-containing polymer, preferably polyvinylchloride (PVC), obtainable through the use of a stabilizing composition comprising DHA (dehydroacetic acid) e DHP (3.5-pyridinedicarboxylicacid) as a synergistic combination.

[0003] STATE OF THE ART

[0004] Polyvinyl chloride (PVC) is a well-known commodity plastic with a broad spectrum of properties. It can be rigid, semi-rigid, and flexible. It is widely used in various construction applications, including water, sewage, or drainage pipes and in many extruded profiles.

[0005] The rigid PVC form has broad acceptance and exhibits a good market growth in major PVC product applications. However, PVC is thermally unstable at processing temperatures.

[0006] When PVC is heated to 170-200°C, chlorine and hydrogen in the molecules are eliminated, and it releases hydrochloric acid (HCI), which in turn accelerates the thermal degradation process of the number of conjugated double bonds formed during the processing. It also causes the level of color in the sample to range from yellow to black. HCI can also deteriorate the mechanical, thermal, and physical properties of PVC. Therefore, heat stabilizers were widely used to safeguard the vinyl products at all stages by improving the heat resistance of PVC products at high temperatures, preventing the chain reaction of degradation.

[0007] Heavy metal-based heat stabilizers such as lead (Pb)-based products are responsible for a large proportion of products in the heat stabilizer group. These products were widely used for the stabilization in Europe. However, recently, the use of Pb has been restricted due to toxicological concerns. Consequently, considerable efforts have been expended towards the development of new stabilization systems for PVC processing, which is driven by a desire to move away from stabilizers based on heavy metal.

[0008] Alternative stabilizers to replace Pb-based stabilizers such as calcium zinc (CaZn) and organic based stabilizers (OBSs) have been investigated. Their usage has been increased both in Europe and, in recent years, due to economic growth, also in emerging markets and producers all over the world are switching to calcium zinc

[0009] 1

[0010] SUBSTITUTE SHEET (RULE 26) and organic alternatives because of legislation, market pressure, or on a voluntary basis, (adapted from Polymers 2022, 14, 133).

[0011] Despite these stabilizers, there is still the need to provide stabilizers capable to lower and / or retard color variation upon PVC processing under thermal heating.

[0012] SUMMARY OF THE INVENTION

[0013] The present inventors surprisingly found out that DHA (dehydroacetic acid, i.e.3- acetyl-6-methyl-2H-pyran-2.4(3H)-dione) and DHP (3.5-pyridinedicarboxylicacid, i.e. didodecyl-1.4-dihydro-2.6-dimethylpyridin-3.5-dicarboxylate) when in specific amounts act synergistically providing low and / or retarded color variation upon halogen-containing polymer processing under thermal heating.

[0014] Therefore, in a first aspect the invention relates to a stabilizing composition comprising DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2,4(3H)- dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-di hydro-2, 6- dimethylpyridin-3,5-dicarboxylate), wherein DHA is in an amount from 1 to 10% w / w, and DHP is in an amount from 0.2 to 6% w / w.

[0015] In a preferred aspect the stabilizing composition comprises also Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1.3-dione), preferably in an amount from 1 to 10% w / w.

[0016] The inventors hence found out a stabilizing composition comprising a combination of DHA and DHP that is capable to provide low and / or retarded color variation upon halogen-containing polymer processing under thermal heating.

[0017] In a further aspect the invention relates to a stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2,6-dimethylpyridin-3,5- dicarboxylate), wherein DHA is an amount from 1 to 99% w / w and DHP is in amount from 99 to 1 % w / w, preferably DHA is from 2 to 98% w / w and DHP from 98 to 2% w / w, more preferably DHA from 56 to 98% w / w and DHP from 44 to 2% w / w, still more preferably DHA about 93% w / w and DHP 7% about w / w.

[0018] In a still further aspect the invention relates to a stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione), DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2,6-dimethylpyridin-3,5- dicarboxylate) and Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1 .3-dione), wherein DHA is in an amount from 1 to 98% w / w, DHP is in an amount from 1 to

[0019] 2

[0020] SUBSTITUTE SHEET (RULE 26) 98% w / w and SBM in an amount from 1 to 98% w / w, preferably DHA from 2 to 96% w / w , DHP from 2 to 96% w / w and SBM from 2 to 96% w / w, more preferably DHA from 2 to 50% w / w, DHP from 2 to 50% w / w and SBM from 2 to 50% w / w, still more preferably DHA about 40% w / w, DHP 10% about w / w and SBM 50%.

[0021] In a further aspect the invention hence concerns a halogenated resin comprising a halogen-containing polymer, preferably polyvinylchloride (PVC), and the stabilizing composition of the invention in an amount in the range from 0.01 to 10 parts by weight, preferably from 0.01 to 5 parts by weight, more preferably 0.1 -1 parts by weight per 100 parts by weight of the halogen-containing polymer (phr).

[0022] The halogenated resin of the invention can be in rigid, semirigid and plasticized formulation.

[0023] When in the present invention the following terms are used:

[0024] - "halogen-containing polymer" means vinyl chloride polymers, including homopolymers, chlorinated polyvinyl chloride (C-PVC), copolymers of vinyl chloride with ethylene-type unsaturated compounds, PVC-VA (vinyl acetate) copolymers, PVC-acrylate, polymer mixtures of polyvinyl chloride with ethyl-vinyl acetate (EVA), acrylic butadiene-styrene (ABS), methacrylate-butadiene-styrene (MBS), acrylonitrile butadiene (NBR), styrene-acrylonitrile (SAN), chlorinated polyethylene (CPE), polyalkylacrylate (PAA), polyalkylmethacrylate (PAMA), polyamides, polylactones;

[0025] - “Halogenated resin in plasticized formulation” or “halogenated resin in semirigid formulation” it is meant a resin comprising the halogen-containing polymer formulated with a certain amount of plasticizer compounds;

[0026] - “Halogenated resin in rigid formulation”, it is meant a resin formulation comprising the halogen-containing polymer and substantially free of plasticizer compounds.

[0027] It was surprisingly found out that the combination of DHA and DHP according to the preferred aspects detailed above has a surprising stabilizing effect when formulated with a halogen-containing polymer, preferably polyvinylchloride (PVC), with respect to their single use.

[0028] In an advantageous and preferred aspect DHP is present in the composition of the invention in an amount from 0.001 to 0.9 parts by weight with respect to 100 parts of the halogen-containing polymer, preferably PVC.

[0029] In a preferred and advantageous aspect, the composition of the invention comprises

[0030] 3

[0031] SUBSTITUTE SHEET (RULE 26) SBM (Stearoyl benzoyl methane, i.e.phenylicosane-1 .3-dione).

[0032] Surprisingly the PVC resin formulation of the invention preferably in the advantageous embodiment with SBM with a synergistic effect allowed an efficient stabilization of the halogen-containing polymer, preferably polyvinylchloride (PVC). In another aspect the invention relates to the use of the composition of the invention for stabilizing polyvinylchloride.

[0033] DETAILED DESCRIPTION OF THE INVENTION

[0034] Therefore the invention relates to a stabilizing composition comprising a combination of DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)- dione) and DHP (3.5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-di hydro-2.6- dimethylpyridin-3.5-dicarboxylate).

[0035] Therefore, in a first aspect the invention relates to a stabilizing composition comprising DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)- dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2.6- dimethylpyridin-3,5-dicarboxylate), wherein DHA is in an amount from 1 to 10% w / w, and DHP is in an amount from 0.2 to 6% w / w with respect to the total amount of the composition.

[0036] Preferably the composition comprises DHA in an amount of about 3.3% w / w. Preferably the composition comprises DHP in an amount of about 1.1 % w / w. In a preferred and advantageous aspect, the composition of the invention comprises SBM named as Stearoyl benzoyl methane having IIIPAC name phenylicosane-1 .3- dione).

[0037] In a still preferred aspect, the stabilizing composition comprises also Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1.3-dione) in an amount from 1 to 10% w / w, more preferably in n amount of 5.5%.

[0038] The inventors hence found out a stabilizing composition comprising a combination of DHA and DHP that is capable to provide low and / or retarded color variation upon halogen-containing polymer processing under thermal heating.

[0039] In a further aspect the invention relates to a stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2,6-dimethylpyridin-3,5- dicarboxylate), wherein DHA is an amount from 1 to 99% w / w and DHP is in amount from 99 to 1 % w / w, preferably DHA is from 2 to 98% w / w and DHP from 98 to 2%

[0040] 4

[0041] SUBSTITUTE SHEET (RULE 26) w / w, more preferably DHA from 56 to 98% w / w and DHP from 44 to 2% w / w, still more preferably DHA is about 93% w / w and DHP is about 7% w / w.

[0042] In a still further aspect the invention relates to a stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione), DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2,6-dimethylpyridin-3,5- dicarboxylate) and Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1 .3-dione), wherein DHA is in an amount from 1 to 98% w / w , DHP is in an amount from 1 to 98% w / w and SBM in an amount from 1 to 98% w / w, preferably DHA from 2 to 96% w / w , DHP from 2 to 96% w / w and SBM from 2 to 96% w / w, more preferably DHA from 2 to 50% w / w, DHP from 2 to 50% w / w and SBM from 2 to 50% w / w, still more preferably DHA about 40% w / w, DHP 10% about w / w and SBM 50%.

[0043] In a further aspect the invention hence concerns a halogenated resin comprising a halogen-containing polymer, preferably polyvinylchloride (PVC), and the stabilizing composition of the invention in an amount in the range from 0.01 to 10 parts by weight, preferably 0.01 to 5 parts by weight, more preferably from 0.1 to 1 parts by weight per 100 parts by weight of polymer (phr).

[0044] In an advantageous and preferred aspect DHP is present in the composition of the invention in an amount from 0.001 to 0.9 parts by weight with respect to 100 parts by weight of the halogen-containing polymer, preferably PVC.

[0045] The halogenated resin comprises the composition comprising from 0.009 to 9 parts by weight of DHA and from 0.001 to 0.74 parts by weight of DHP with respect to 100 parts of halogen-containing polymer, preferably PVC.

[0046] Preferably the halogenated resin comprises the stabilizing composition comprising 0.25 parts by weight of DHA and 0.02 parts by weight of DHP per 100 parts by weight of the halogen-containing polymer.

[0047] The composition comprises DHA.

[0048] DHA is named as dehydroacetic acid, having IIIPAC name

[0049] 3-acetyl-6-methyl-2H-pyran-2.4(3H)-dione of formula

[0050] The composition comprises DHP.

[0051] 5

[0052] SUBSTITUTE SHEET (RULE 26) DHP is named as 3.5-pyridinedicarboxylic acid, having IIIPAC name didodecyl-1 .4- dihydro-2.6-dimethylpyridin-3.5-dicarboxylate of Formula

[0053] The halogenated resin of the invention can be in rigid, semirigid and plasticized formulation.

[0054] It was surprisingly found out that the combination of DHA and DHP has a surprising stabilizing effect when formulated with PVC with respect to their single use.

[0055] Preferably the stabilizing composition comprises SBM, more preferably in an amount in the range from 0.01 to 10 parts by weight, more preferably in the range from 0.01 to 5 parts by weight, still more preferably from 0.1 to 1 parts by weight with respect to 100 parts of the halogen-containing polymer, preferably polyvinyl chloride (PVC).

[0056] Surprisingly the halogen-containing polymer resin formulation of the invention, preferably in the advantageous embodiment with SBM, allowed an efficient stabilization of the halogen-containing polymer.

[0057] The stabilizing composition comprised in the resin formulation of the invention can also comprise one or more stabilizers and co-stabilizers other than tin stabilizer. In a preferred embodiment the composition does not comprise a tin stabilizer.

[0058] The optional stabilizers or costabilizers can be present in the composition of the first aspect of the invention or can be present in the resin formulation.

[0059] The optional stabilizers or costabilizers can be selected from the group consisting of metal soaps, perchlorates and perfluoroalkanesulphonates, disodium adipate, antioxidants, alkanolamines, zeolites and hydrotalcites7polyols, organic phosphites, [3-ami nocroton ic acid esters and organic co-stabilizers such as dihydropyridines, polydihydropyridines and uracil derivatives.

[0060] The optional stabilizer is preferably comprised in the resin in an amount in the range from 0.05 to 5 parts by weight per 100 parts by weight of the halogen-containing polymer, preferably PVC.

[0061] The following can be cited as non-limiting examples of stabilizers.

[0062] Metal soaps

[0063] All metal soaps known for use with a halogen-containing polymer as polyvinyl

[0064] 6

[0065] SUBSTITUTE SHEET (RULE 26) chloride (PVC) stabilizers are suitable for the invention. These are preferably organic sodium, lithium, potassium, calcium, zinc, magnesium and aluminium salts of saturated C2-C22 aliphatic carboxylates, unsaturated C2-C22 aliphatic carboxylates, saturated C2-C22 aliphatic carboxylates substituted with at least one OH group, or whose chain is interrupted by at least one oxygen atom (oxyacids), cyclic or bicyclic carboxylates containing from 5 to 22 carbon atoms, phenylcarboxylates, unsubstituted or substituted with at least one OH group and / or substituted with C1-C16 alkyl, naphthylcarboxylates, unsubstituted or substituted with at least one OH group and / or substituted with C1-C16 alkyl, phenyl- (C1- Ci6)alkylcarboxylates, naphthyl-(Ci-C-i6)alkylcarboxylates, or phenolates, unsubstituted or substituted with C1-C12 alkyl.

[0066] Among these, the following can be cited: metal salts of monovalent carboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, n- heptanoic acid, octanoic acid, neodecanoic acid, 2-ethylhexanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, myristic acid, palmitic acid, lauric acid, isostearic acid, stearic acid, 12-hydroxystearic acid,

[0067] 9.10-dihydroxystearic acid, oleic acid, 3,6-dioxaheptanoic acid, 3,6,9-trioxadecanoic acid, behenic acid, benzoic acid, p-tert-butylbenzoic acid, dimethylhydroxybenzoic acid, 3,5-di-tert-butyl4-hydroxybenzoic acid, toluic (methylbenzoic) acid, dimethylbenzoic acid, ethylbenzoic acid, n-propylbenzoic acid, salicylic acid, p-tert- octylsalicylic acid and sorbic acid; metal salts of bivalent or monoesterified carboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, pentane-1 ,5-dicarboxylic acid, hexane-1 ,6-dicarboxylic acid, heptane-1 ,7-dicarboxylic acid, octane-1 ,8-dicarboxylic acid, 3,6,9-trioxadecane-

[0068] 1 .10-dicarboxylic acid, lactic acid, malonic acid, maleic acid, tartaric acid, oxalic acid, salicylic acid, phthalic acid, isophthalic acid, terephthalic acid, hydroxyphthalic acid, and the diesters or triesters of tri- or tetra-valent carboxylic acids such as hemimellitic acid, trimellitic acid, pyromellitic acid, citric acid, and metal salts of mono- or di-esterified phosphoric acid or monoesterified phosphorous acid as described in JP 3275570; and colophonic acids (rosin acids such as abietic acid), and superbasic carboxylates.

[0069] Metal soaps preferred in the present invention are metal carboxylates of a carboxylic acid containing from 2 to 25 carbon atoms, being typically, acetates, benzoates, or

[0070] 7

[0071] SUBSTITUTE SHEET (RULE 26) alkanoates, and preferably Cs-alkanoates, stearates, oleates, laurates, palmitates, behenates, versatates, hydroxystearates, dihydroxystearates, p-tert- butylbenzoates, and 2-ethylhexanoates.

[0072] According to the invention, a mixture of carboxylates of different structure can also be used as metal soaps. Preference is given to the compositions as aforedescribed containing sodium, zinc and / or calcium soaps.

[0073] Zn, Li, K, Mg, Ca, Na salts of the stated fatty acids containing from 2 to 25 carbon atoms are preferably added to the resin or to the composition / product of the invention.

[0074] Non-metal stabilizers

[0075] Among metal-free stabilizers esters of [3-aminocrotonic acid can be cited.

[0076] Considered suitable among these compounds are for example [3-aminocrotonic acid stearyl ester, 1 ,4-butanediol-di([3-aminocrotonic acid) ester, thio-diethanol-[3- aminocrotonic acid ester.

[0077] Perchlorates and perfluoroalkanesulphonates

[0078] The polymer stabilizing composition can also comprise a compound selected from the group consisting of M(CIO4)k and M(CF3SO3)n in which M is selected from the group consisting of H+, Li+, Na+, K+, Mg2+, Ca2+, Ba2+, Zn2+, Al3+and NH4+, and k and n are 1 , 2 or 3 depending on the valency of M.

[0079] M is preferably selected from the group consisting of Li+, Na+, K+, Mg2+, Ca2+and Zn2+, more preferably M is selected from the group consisting of Na+, K+and Ca2+, and still more preferably it is sodium.

[0080] In case of use of a compound of formula M(CF3SO3)n, this is preferably trifluoromethanesulphonic acid or a sodium salt thereof, more preferably it being sodium trifluoromethanesulphonate.

[0081] Preferred for the purposes of the invention is the use of perchloric acid or perchlorate salts. These can be used in various forms, for example preparations such as salts or aqueous or organic solutions, supported on various materials such as PVC, calcium silicate, zeolites or hydrotalcites or bound to a hydrotalcite by chemical reaction.

[0082] Furthermore, the preferred perchlorates of the invention are complexes of metal perchlorate, more preferably sodium perchlorate, with triethylene glycol, butyldiglycol or polyethylene glycol.

[0083] 8

[0084] SUBSTITUTE SHEET (RULE 26) The composition of the invention can also comprise other additives / excipients able to behave as co-stabilizers, selected from the group consisting of antioxidants, organic co-stabilizers ([3-diketones and dihydropyridines or polydihydropyridines, uracil derivatives), alkanolamines, zeolites and hydrotalcites, polyols, hydrates and oxides of alkali and alkaline-earth metals and organic phosphites.

[0085] Antioxidants

[0086] The organic antioxidants used in the present invention are selected from those already known as additives for plastic materials. For the purposes of the invention, preferred are one or more antioxidants selected from the group consisting of alkylidene-bisphenols, esters of [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or poly-alcohols, esters of [3-(5-tert-butyl-4-hydroxy-3- methylphenyl)propionic acid with mono- or poly-alcohols, esters of |3-(3,5- dicyclohexyl~4-hydroxyphenyl)propionic acid with mono- or poly-alcohols.

[0087] Particularly preferred according to the invention are 2,2’-methylene-bis(6-tert-butyl- 4-methylphenol), commercially available as Lowinox® 22 M46 produced by Chemtura, and esters of [3-(3.5-di-tert-butyl-4-hydroxyphenyl)propionic acid with octadecanol and with pentaerythritol, respectively Arenox® A76 and Arenox® A10, produced by Reagens, and bisphenol A.

[0088] The aforedescribed antioxidants, if present, are preferably included in an amount within the range from 0.01 to 1.0 parts by weight, more preferably from 0.1 to 0.5 parts by weight, per 100 parts by weight of PVC.

[0089] Organic co-stabilizers

[0090] The invention also provides for the optional presence of organic co-stabilizers in the composition of the invention to further increase the effectiveness of the stabilizing composition. The organic co-stabilizers optionally present in the stabilizing composition of the invention can be preferably one or more compounds selected from dihydropyridines, polydihydropyridines, and uracil derivatives.

[0091] The uracil derivatives advantageously present in the composition of the invention are described by general formula (III):

[0092] 9

[0093] SUBSTITUTE SHEET (RULE 26) wherein:

[0094] R4and R5are, independently of one another, hydrogen, C1-C12 alkyl, C3-C6 alkenyl, Cs-Cs cycloalkyl optionally substituted with 1 to 3 C1-C4 alkyl, C1-C4 alkoxy, Cs-Cs cycloalkyl or hydroxyl or with chlorine atoms, or C7-C9 phenylalkyl optionally substituted on the phenol ring with 1 to 3 C1-C4 alkyl, C1-C4 alkoxy, Cs-Cs cycloalkyl or hydroxyl or with chlorine atoms; Y can be oxygen or sulphur.

[0095] Examples of C1-C4 alkyl are methyl, ethyl, n-propyl, isopropyl, n-, iso-, sec-, or tertbutyl.

[0096] Examples of C1-C12 alkyl are, in addition to the aforementioned radicals, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, isooctyl, nonyl, decyl, undecyl, dodecyl.

[0097] Examples of C1-C4 alkoxy are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy.

[0098] Examples of Cs-Cs cycloalkyl are cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl.

[0099] Examples of C7-C9 phenylalkyl are benzoyl, 1 - or 2- phenylethyl, 3-phenylpropyl, a,a-dimethylbenzyl, or 2-phenylisopropyl, preferably benzyl. If the cycloalkyl or phenyl groups of the phenylalkyl radical are substituted, then they are substituted with one or two substituents, preferably selected from chlorine, hydroxyl, methyl or methoxy.

[0100] Examples of Cs-Cs alkenyl are allyl, methallyl, 1 -butenyl, or 1 -hexanyl, preferably allyl.

[0101] Preferred are the compounds of the aforestated formula, in which R4and R5are, each independently of the other, C1-C4 alkyl and hydrogen; in particular, the compound in which R4and R5are methyl is preferred.

[0102] Among the uracil derivatives there can also be optionally present in the composition of the invention oligomeric or polymeric derivatives of formula (III’):

[0103] 10

[0104] SUBSTITUTE SHEET (RULE 26) wherein:

[0105] A is n-octyl, n-octadecyl, oleyl, phenyl, cyclohexyl or 3-hydroxyphenyl and

[0106] B is hexamethylene, 3-methylene-3,5,5-trimethylcyclohexan-1-yl, 4,4’-methylene- bis-cyclohexyl, 4,4’-methylene -bis-phenyl,

[0107] X is oxygen, or if A is phenyl and B is hexamethylene, then X is sulphur; k varies from 0 to 17, preferably from 0 to 2. The oligomer derivatives described above are preferred in the invention.

[0108] The aforedescribed organic co-stabilizers can be present preferably in an amount within the range from 0.01 to 1.0 parts by weight, in particular from 0.1 to 0.5 parts by weight, per 100 parts by weight of the halogen-containing polymer.

[0109] Alkanolamines

[0110] Alkanolamines, advantageously present in the composition of the invention and in the final resin of the invention, are compounds of general formula (IV): wherein x = 1 , 2, 3; y = 1 , 2, 3, 4, 5 or 6; n

[0111] SUBSTITUTE SHEET (RULE 26) n is from 1 to 10

[0112] R1and R2are independently H, C1-C22 alkyl,

[0113] C2-C20 alkenyl, C2-C18 acyl, C4-C8 cycloalkyl, which can also be hydroxyl-substituted in position (3, Ce-C-io aryl, C7-C10 arylalkyl or alkylaryl, or if x = 1 , then R1and R2can be additionally combined with nitrogen to form a cyclo of 4-10 carbon atoms and optionally up to 2 heteroatoms, or if x = 2, then R1can additionally be C2-C18 alkylene, which can be hydroxylsubstituted at both carbon atoms in [3 and / or can be interrupted by one or more NR groups;

[0114] Ra3, Rb3are independently C1-C22 alkyl, C2-C6 alkenyl, Ce-C-io aryl, H or CH2-X-R5, where X is oxygen, sulphur, -O-CO- or CO-O-;

[0115] R4is C1-C18 alkyl, alkenyl or phenyl and

[0116] R5is H, C1-C22 alkyl, C2-C22 alkenyl, or Ce-C-io aryl.

[0117] Preferred trialkanolamines of general formula (IV) are those in which Ra3, Rb3are, each independently of the other, H or methyl, and y = 1 .

[0118] Other alkanolamines are diamines of general formula (V): wherein: n is an integer from 3 to 4, x, y, z are independently of each other an integer from 1 to 20, w is an integer from 1 to 2, R1is a C8-C20 hydrocarbon residue of a compound selected from the group consisting of tallow, cottonseed oil, soya bean oil, and coconut oil. The diamine (V) of the invention is advantageously N,N’,N’-tris(3- hydroxypropyl)-N-coco-alkyl-1.3-propanediamine, N,N,N’-(2-hydroxyethyl)-N’-Ci2- i8-alkyl-1 ,3-propanediamine, N,N’,N’-tris-(2-hydroxyethyl)-N-tallow-alkyl-1 ,3- propanediamine, N,N’,N’-polyoxyethylene(15)-N-tallow-alkyl-1 ,3-propanediamine, or N,N’,N’-tris(2-hydroxyethyl)-N-coco-alkyl-1 ,3-propanediamine.

[0119] Examples of preferred alkanolamines according to the general formula are:

[0120] 12

[0121] SUBSTITUTE SHEET (RULE 26) tri(hydroxyethyl)amine, tri(hydroxypropyl)amine.

[0122] The aforedescribed alkanolamines can be present preferably in an amount within the range from 0.01 to 1.0 parts by weight, in particular from 0.1 to 0.5 parts by weight, per 100 parts by weight of polymer and are preferably used in combination with perchlorates and perfluoroalkanesulphonates.

[0123] Hydrotalcites

[0124] The hydrotalcites optionally present in the compositions of the invention can be described by the following general formula:

[0125] [M2+i.xM3+x(OH)2]x+[An-x / nmH2O]x- wherein M2+represents at least one bivalent metal cation of the group consisting of Mg, Zn, Ni, Ca; M3+represents at least one trivalent metal cation of the group consisting of Al, Fe; An-is an anion having a valency comprised between 1 and 4; x and m represent positive numbers which satisfy the following expressions

[0126] 0.2 < x < 0.33 and m > 0.

[0127] In the general formula above, Anrepresents an anion selected from the group consisting of CO32; OH; HCO3; CIO4; NO3; I; [Fe(CN)e]4; acetate, salicylate, tartrate (bivalent) and oxalate (bivalent).

[0128] The preferred hydrotalcites of the invention are those in which An-is selected from CO32; OH’.

[0129] The preferred empirical formulas for hydrotalcite considered for the invention are: Mg6AI2(OH)i6CO3- H2O

[0130] Mg4AI2(OH)i2CO3'3H2O

[0131] Zeolites

[0132] The zeolites optionally present in the compositions of the invention can be described by the general formula:

[0133] Mq / a[(AIO2)q(SiO2)r] wH2O in which a is the charge on the cation M,

[0134] M is an element of the alkali or alkaline-earth metal group, in particular Na, K, Mg, q is a number greater than or equal to 2, the q / r ratio is a number greater than or equal to 0.4, being preferably a number between 0.4 and 10.5, and w is a number between 0 and 300.

[0135] The preferred zeolites, optionally present in the composition of the invention, are

[0136] 13

[0137] SUBSTITUTE SHEET (RULE 26) described in “Atlas of Zeolite Structure Types”, W. M. Meier and D. H. Olson, Butterworths, 3rd Edition, 1992.

[0138] Particularly preferred are zeolites having a particle size mainly within the range from 0.5 to 10 micron.

[0139] The preferred zeolites, which are known per se, have an effective mean cavity diameter of 3-5 A and can be prepared by known methods.

[0140] Also particularly preferred are zeolites of type NaA, which have an effective mean cavity diameter of 4 A, and are hence known as 4A zeolites, indicated by the formula:

[0141] Nai2Ali2Sii2O48'27H2O.

[0142] Particular preference is given to those zeolites satisfying the aforestated general formula, known as X zeolites and indicated by the formula (Na2,Ca,Mg)29Al58Sii34O384'240H2O.

[0143] Polyols

[0144] Among the polyols, optionally present in the composition of the invention, the following are preferred: pentaerythritol, dipentaerythritol, tripentaerythritol, bistrimethylolpropane, bistrimethylolethane, trimethylolpropane, inosite, polyvinyl alcohol, sorbitol, maltite, isomaltite, lactite, licasine, mannitol, lactose, leucrose, tris(hydroxyethyl)isocyanurate, palatinite, tetramethylolcyclohexanol, tetramethylolcyclopentanol, tetramethylolcyclopyranol, glycerol, diglycerol, polyglycerol, thiodiglycerol, or 1 -0-a-D-glycopyranosyl-D-mannitol dihydrate.

[0145] Most preferred among polyols are tris(hydroxyethyl)isocyanurate (THEIC), pentaerythritol, dipentaerythritol, trimethylolpropane, bistrimethylolpropane, sorbitol.

[0146] The polyols, if present, are present preferably in an amount within the range from 0.01 to 2 parts by weight, more preferably from 0.1 to 1 parts by weight, per 100 parts by weight of halogen-containing polymer. Phosphites

[0147] The phosphites, optionally present in the composition of the invention, are preferably organic phosphites of general formula P(OR)3, in which the radicals R are identical or different and can be Ce-C-is alkyl, Ce-C-is alkenyl, C5-C7 cycloalkyl. Also included as preferred in the invention are acid phosphites of general formula P(OH)R2, in

[0148] 14

[0149] SUBSTITUTE SHEET (RULE 26) which the radicals R are identical or different and selected from Ce-C-is alkyl, Ce-C-is alkenyl, phenyl, mono- or di-alkylphenyl, or C5-C7 cycloalkyl.

[0150] Phosphites with the following general formula can also be present in the composition of the invention: in which R1and R2are identical or different and are Ce-C-is alkyl, Ce-C-is alkenyl, phenyl, mono- or di-alkylphenyl, or C5-C7 cycloalkyl. Preferred of these latter phosphites are those in which R1, R2= stearyl or

[0151] Phosphites with the following general formula can also be present: wherein R1and R3are identical or different and are Ce-C-is alkyl, Ce-C-is alkenyl, phenyl, mono- or di-alkylphenyl, or C5-C7 cycloalkyl, R2is alkyl, alkyloxy, aryl or arylalkyl.

[0152] Each C6-C18 alkyl substituent present is, for example, n-hexyl, n-octyl, n-nonyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl. Preferred are groups having from 8 to 18 carbon atoms.

[0153] The preferred phosphites in the present invention include: tri(isodecyl)phosphite, tri(nonylphenyl)phosphite, tri(isotridecyl)phosphite, diphenyl isodecyl phosphite, di(isodecyl) phenyl phosphite, di(nonylphenyl) phosphite, tetraphenyl dipropyleneglycol diphosphite, 4,4’ isopropylidenediphenol tetra(Ci2-is alcohol) phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearyl

[0154] 15

[0155] SUBSTITUTE SHEET (RULE 26) pentaerythritol diphosphite.

[0156] The phosphites, if present, are preferably in an amount within the range from 0.1 to 2 parts by weight, more preferably from 0.2 to 0.5 parts by weight, per 100 parts by weight of the halogen-containing polymer, preferably PVC.

[0157] In a preferred embodiment of the invention the stabilizing composition consists of DHP and DHA, preferably DHP, DHA and SBM in an amount preferably from 0.01 to 10 parts by weight, more preferably from 0.01 to 5 parts by weight, still more preferably 0.1 -1 parts by weight per 100 parts of halogen-containing polymer, preferably polyvinylchloride.

[0158] The halogenated resin of the invention can be in a rigid, semirigid and plasticized formulation.

[0159] The halogenated resin can be a plasticized or semirigid formulation comprising chlorinated polyvinylchloride formulated with plasticizer compounds.

[0160] The halogenated resin can be a rigid formulation comprising polyvinylchloride and being substantially free of plasticizer compounds.

[0161] The compounds present in the stabilizing composition can be added to the resin formulation by mixing through dry blending. The resin formulation is then used to prepared final articles of PVC. The final products article can be any type of PVC product, which needs an enhanced thermal stabilization, for example: rigid and semirigid films, sheets, profiles, cables, automotive parts, floorings, roofing, injection molded articles. The finished items may be manufactured by any process available to those of ordinary skill in the art including, but not limited to, extrusion, extrusion blowing, film casting, film blowing, calendering, injection molding, compression molding, thermoforming, spinning, rotational casting, slush molding, plastisol curing. In another aspect the invention relates to the use of the composition of the invention for stabilizing polyvinylchloride.

[0162] In another aspect the invention relates to the use of a composition of DHA and DHP in an amount of preferably from 0.01 to 10 parts by weight, more preferably from 0.01 to 5 parts by weight, still more preferably 0.1 -1 parts by weight per 100 parts of the halogen-containing polymer for stabilizing a halogen-containing polymer.

[0163] The invention will be now detailed by illustrative and non-limitative examples. Experimental part

[0164] Different examples were carried out on PVC samples containing different amount of

[0165] 16

[0166] SUBSTITUTE SHEET (RULE 26) DHA, DHP and SBM.

[0167] The degradation rate in terms of b* of according to DIN 5033 was measured, b* is a measure of the degradation of the sample.

[0168] The higher is b*, the higher is yellowing and, thus, the higher is the degradation). Example 1 (synergism DHA + DHP and synergism DHA + DHP + SBM)

[0169] The formulations indicated in the following table 1 were tested using a Weber CE3 extruder (at melt temperature of 180°C).

[0170] Residual thermal stability was evaluated exposing the extruded samples in oven at 180C° for 30, 45 minutes and measuring the colour in term of b* Four Samples were comparative containing either DHA, DHP or SBM, invention example 1 contained both DHA and DHP, while invention example 2 contained DHA, DHP and SBM-

[0171] All the amounts are expressed by parts by weight.

[0172] Table 1

[0173] 17

[0174] SUBSTITUTE SHEET (RULE 26)

[0175] | SUM OF SBM, DHA, DHP | 0.000 | 0.30 | 0.30 | 0.30 | 0.30 | 0.30 |

[0176] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 2 and 3 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention.

[0177] The same occurred with the composition of the invention containing DHA, DHP and SBM (sample 2 of the invention) that produced better results that the comparative samples containing the same amount of the single DHA, DHP and SBM, respectively.

[0178] Samples of the invention therefore demonstrated the synergism between DHA and DHP, and among DHA, DHP and SBM.

[0179] 18

[0180] SUBSTITUTE SHEET (RULE 26) Example 2 (synergism DHA + PHP)

[0181] The formulations indicated in the following table 2 were tested using a Bausano MD30 extruder (at melt temperature of 180°C) measuring the colour of the extruded samples in term of b* according to DIN 5033. All the amounts were expressed in parts by weight.

[0182] Table 2

[0183] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 1 ,2 and 3 that contained DHA, DHP and SBM, respectively in a total amount that was the same of the composition of the invention.

[0184] 19

[0185] SUBSTITUTE SHEET (RULE 26) As it deducible from the value of b the effects obtainable by the invention were the result of a synergism of DHA and DHP, when put together in the same composition. Example 3 (synergism DHA + PHP)

[0186] The formulations indicated in the following table 3 were tested using a Brabender Plasticorder (at 180°C, 40 rpm, 60 g sample, 5 minutes), and measuring the colour of the obtained samples in term of b* according to DIN 5033.

[0187] All the amounts were expressed in parts by weight.

[0188] Table 3

[0189] 20

[0190] SUBSTITUTE SHEET (RULE 26)

[0191] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 1 and 2 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention. As it deducible from the value of b the effects obtainable by the invention were the result of a synergism of DHA and DHP, when put together in the same composition. The composition of the invention contained also SBM and the result was better than the association of SBM with either DHA and DHP.

[0192] Example 4 (synergism DHA + DHP) The formulations indicated in the following table 4 were tested using a Brabender Plasticorder (at 180°C, 40 rpm, 60 g sample, 5 minutes) followed by a two roll mill calendaring at 190°C for 3 minutes) and measuring the colour of the obtained samples in term of b* according to DIN 5033.

[0193] All the amounts were expressed in parts by weight. Table 4

[0194] 21

[0195] SUBSTITUTE SHEET (RULE 26)

[0196] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 1 and 2 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention.

[0197] As it deducible from the value of b the effects obtainable by the invention were the result of a synergism of DHA and DHP, when put together in the same composition. The composition of the invention contained also SBM and the result was better than the association of SBM with either DHA and DHP. Example 5 (synergism DHA + DHP and synergism DHA + DHP + SBM)

[0198] The formulations indicated in the following table 5 were tested using a Brabender Plasticorder (at 180°C, 40 rpm, 60 g sample, 5 minutes), and measuring the colour of the obtained samples in term of b* according to DIN5033.

[0199] All the amounts were expressed in parts by weight. Table 5

[0200] 22

[0201] SUBSTITUTE SHEET (RULE 26)

[0202] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 2 and 3 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention.

[0203] The same occurred with the composition of the invention containing DHA, DHP and SBM (sample 2 of the invention) that produced better results that the comparative samples containing the same amount of the single DHA, DHP and SMP, respectively. Samples of the invention therefore demonstrated the synergism between DHA and DHP, and among DHA, DHP and SBM.

[0204] Example 6 (synergism DHA + DHP)

[0205] The formulations indicated in the following table 6 were tested using a Bausano MD30 extruder (at melt temperature of 180°C) measuring the colour of the extruded samples in term of b* according to DIN5033.

[0206] All the amounts were expressed in parts by weight.

[0207] 23

[0208] SUBSTITUTE SHEET (RULE 26) Table 6

[0209] As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 1 and 2 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention.

[0210] 24

[0211] SUBSTITUTE SHEET (RULE 26) The surprising synergism between the two compounds was more evident with respect to the comparative example 3, containing DHP in the same amount of the composition of the invention.

[0212] The composition of the invention contained also SBM and the result was better than the association of SBM with either DHA and DHP.

[0213] Example 7 (synergism DHA + DHP)

[0214] The formulations indicated in the following table 7 were processed in a two roll mill (at 195°C for 3 minutes). The obtained sheets were pressed at 180°C for 4 minutes into 2 mm compression molded plaques measuring the colour of the obtained samples in term of b* according to DIN5033.

[0215] All the amounts were expressed in parts by weight.

[0216] Table 7 It is evident that there is a synergism between DHA and DHP (20REAZmall2 and 20REAZmaU3 vs. 20REAZmaU11 ).

[0217] 25

[0218] SUBSTITUTE SHEET (RULE 26) As it is evident the sample 1 of the invention showed better colour when compared to the comparative samples 1 and 2 that contained DHA and DHP, respectively in a total amount that was the same of the composition of the invention.

[0219] The surprising synergism between the two compounds was more evident with respect to the comparative example 3 and comparative example 4, containing DHA and DHP, respectively, in the same amount of the composition of the invention.

[0220] 26

[0221] SUBSTITUTE SHEET (RULE 26)

Claims

CLAIMS1. A stabilizing composition comprising DHA (dehydroacetic acid, i.e.3-acetyl-6- methyl-2H-pyran-2.4(3H)-dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2.6-dimethylpyridin-3,5-dicarboxylate), wherein DHA is in an amount from 1 to 10% w / w, and DHP is in an amount from 0.2 to 6% w / w with respect to the total amount of the composition.

2. The stabilizing composition according to claim 1 , wherein the composition further comprises Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1 ,3-dione), preferably in an amount from 1 to 10% w / w.

3. A stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6- methyl-2H-pyran-2.4(3H)-dione) and DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl-1 ,4-dihydro-2,6-dimethylpyridin-3,5-dicarboxylate), wherein DHA is an amount from 1 to 99% w / w and DHP is in amount from 99 to 1 % w / w, preferably DHA is from 2 to 98% w / w and DHP from 98 to 2% w / w, more preferably DHA from 56 to 98% w / w and DHP from 44 to 2% w / w, still more preferably DHA is about 93% w / w and DHP is about 7% w / w.

4. A stabilizing composition consisting of DHA (dehydroacetic acid, i.e.3-acetyl-6- methyl-2H-pyran-2.4(3H)-dione), DHP (3,5-pyridinedicarboxylicacid, i.e. didodecyl- 1 ,4-dihydro-2,6-dimethylpyridin-3,5-dicarboxylate) and Stearoyl Benzoyl Methane (SBM, i.e. phenylicosane-1 .3-dione), wherein DHA is in an amount from 1 to 98% w / w , DHP is in an amount from 1 to 98% w / w and SBM in an amount from 1 to 98% w / w, preferably DHA from 2 to 96% w / w , DHP from 2 to 96% w / w and SBM from 2 to 96% w / w, more preferably DHA from 2 to 50% w / w, DHP from 2 to 50% w / w and SBM from 2 to 50% w / w, still more preferably DHA about 40% w / w, DHP 10% about w / w and SBM 50%.

5. A halogenated resin comprising a halogen-containing polymer and the stabilizing composition according to claims 1 -4.

6. The halogenated resin according to claim 5, wherein the halogen-containing polymer is polyvinyl chloride (PVC).

7. The halogenated resin according to claim 5 or 6, wherein the stabilizing composition is in an amount in the range from 0.01 to 10 parts by weight per 100 parts by weight of the halogen-containing polymer (phr).

8. The halogenated resin according to anyone of claims 5 to 7, wherein the 1SUBSTITUTE SHEET (RULE 26)stabilizing composition comprises DHP from 0.001 to 0.9 parts by weight with respect to 100 parts by weight of the halogen-containing polymer.

9. The halogenated resin according to anyone of claims 5 to 8, wherein the stabilizing composition comprises DHA in an amount from 0.009 to 9 parts by weight and from 0.001 to 0.74 parts by weight of DHP with respect to 100 parts of the halogen-containing polymer,10. The halogenated resin according to anyone of claims 5 to 9, wherein the stabilizing composition comprises 0.25 parts by weight of DHA and 0.02 parts by weight of DHP per 100 parts by weight of the halogen-containing polymer.

11. The halogenated resin according to anyone of claims 5 to 10, wherein the stabilizing composition comprises SBM in an amount in the range from 0.01 to 10 parts by weight, preferably in the range from 0.01 to 5 parts by weight, more preferably from 0.1 to 1 parts by weight with respect to 100 parts by weight of the halogen-containing polymer.

12. The halogenated resin according to anyone of claims 5 to 11 , wherein the halogenated resin is formulated in rigid, semirigid or plasticized formulation.

13. The halogenated resin according to anyone of claims 5 to 12, wherein the resin comprises one or more stabilizers and co-stabilizers selected from the group consisting of metal soaps, perchlorates and perfluoroalkane sulphonates, monosodium adipate, antioxidants, alkanolamines, zeolites and hydrotalcites, polyols, organic phosphites, [3-aminocrotonic acid esters and organic co-stabilizers such as dihydropyridines, polydihydropyridines and uracil derivatives.

14. A use of the composition according to claims 1 -4 for stabilizing a halogencontaining polymer.28SUBSTITUTE SHEET (RULE 26)

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