DESCRIPTION FIELD OF THE INVENTION

The invention concerns a stabilized chlorinated polyvinylchloride (CPVC) having also an appropriate short fusion time. The stabilized CPCV is obtainable through the use of a stabilizing composition comprising disodium adipate in suitable amounts and in absence of stannous and stannic stabilizers.

STATE OF THE ART

Chlorinated polyvinyl chloride (CPVC) is gaining more and more importance in the industry in view of its superior mechanical properties with respect to PVC (Journal of Vinyl and Additive Technology1986, 8(4), 146-150). In particular PVC has a higher VICAT softening temperature than PVC.

Halogen-containing polymers must be subjected to temperatures within more or less wide range around 190 °C in order to be worked by known processes, such as molding, calendaring and extrusion.

It is known that halogen-containing polymers tend to degrade at the above cited processing temperatures due to the inherent degradation temperature of the halogenated polymers themselves, that at said temperatures release hydrochloric acid with formation of double bonds.

These alteration phenomena of the structure of the chlorinated polymers manifest themselves as a deterioration of the mechanical properties and a darkening effect in colour. This problem of deterioration is exacerbated when the residence time at higher temperature during working is longer.

Tin stabilizers are traditionally used as CPVC stabilizers but it is known that they are toxic and it is desirable to eliminate them from stabilizing compositions for halogenated polymers.

Moreover, presently known CPVC stabilizers provide a limited thermal stability. In US 2017/0029593 a composition resin for molding including a chlorinated vinyl chloride, a thermal stabilizer a polyalcohol and/or a partial ester of a polyalcohol is described. The stabilizing composition for CPVC is proposed with the aim of avoiding the use of metal stabilizers, specifically tin stabilizers. The herein described thermal stabilizer contains at least one of a compound represented by the formula Cai-xZn _x (OH)2, where x satisfies the inequality 0<x<1 and a compound represented by the formula Cai- _y Zn _y O where y satisfies the inequality 0<y<1. In EP2083044 a stabilizing composition for halogen-containing polymers comprising disodium adipate and at least one compound selected from the group consisting of metal perchlorates and trifluoro-sulfates is proposed. In Example 4 the stabilization of C-PVC is suggested, but the final stabilizing composition still contains tin derivative stabilizers in order to guarantee good Congo red (CR) stabilities with low yellowness indexes.

Furthermore, in case of CPVC it is also desirable to have an appropriately short time to fusion in processing (as for example in an extruder) to obtain good quality articles.

Therefore it is still felt the need of a stabilizing composition, that guarantees good stabilizing effects in absence of tin stabilizers and is capable to give appropriately short time to fusion in processing in order to obtain good quality articles.

SUMMARY OF THE INVENTION

The present inventors surprisingly found out that disodium adipate used in a specific amount can efficiently stabilize chlorinated polyvinylchloride with also heat short fusion time, when used in a stabilizing composition that does not contain tin stabilizers.

In a first aspect the invention hence concerns a halogenated resin comprising chlorinated polyvinylchloride (CPVC) and a stabilizing composition comprising disodium adipate in an amount above 0.3 parts by weight per 100 parts of polymer (phr) and wherein the halogenated resin does not comprise tin stabilizers.

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

When in the present invention the following terms are used:

- “Halogenated resin in plasticized formulation” or“halogenated resin in semirigid formulation” it is meant a resin comprising chlorinated polyvinylchloride formulated with a certain amount of plasticizer compounds; - “Halogenated resin in rigid formulation”, it is meant a resin formulation comprising chlorinated polyvinylchloride and substantially free of plasticizer compounds.

The stabilizing composition of the invention comprises the salt disodium adipate as essential component in an amount above 0.3 parts by weight per 100 parts of CPVC.

It was surprisingly found out that the specific amount of disodium adipate has a surprising stabilizing effect when formulated with CPVC with respect to PVC, even in absence of tin stabilizers. Surprisingly the CPVC resin formulation of the invention showed short fusion time, thus allowing a better workability of the resin itself.

In a preferred embodiment, the disodium adipate of the stabilizing composition shows a particle size distribution showing a D90 value lower than 32.0 micron, a D50 value lower than 9.6 micron and a D10 value lower than 0.8 micron.

The present inventors surprisingly also found out that disodium adipate stabilizes chlorinated polyvinylchloride at a particularly efficient extent if fine in particle size. As disodium adipate is particularly useful in solid form providing easier handling, the particle size of the disodium adipate is of peculiar technical importance.

In another aspect the invention relates to the use of disodium adipate in an amount of above 0.3 parts by weight per 100 parts of polymer for stabilizing chlorinated polyvinylchloride in absence of tin stabilizers.

DETAILED DESCRIPTION OF THE INVENTION

Therefore the invention relates to a halogenated resin comprising chlorinated polyvinylchloride (CPVC) and a stabilizing composition comprising disodium adipate in an amount above 0.3 parts by weight per 100 parts of polymer (phr) and wherein the halogenated resin does not comprise tin stabilizers.

The disodium adipate salt of the stabilizing composition of CPVC resin is present in an amount of above 0.3 parts by weight per 100 parts of polymer (phr), preferably from 0.35 to 1.6, still more preferably equals to 0.9 parts by weight per 100 parts by weight of CPVC.

In a preferred embodiment, the disodium adipate of the stabilizing composition shows a particle size distribution showing a D90 value lower than 32.0 micron, a D50 value lower than 9.6 micron and a D10 value lower than 0.8 micron.

More preferably, the disodium adipate of the stabilizing composition shows a particle size distribution showing a D90 value lower than 16.0 micron, a D50 value lower than 4.8 micron and a D10 value lower than 0.7 micron.

Even more preferably, the disodium adipate of the stabilizing composition shows a particle size distribution showing a D90 value lower than 8.0 micron, a D50 value lower than 1.8 micron and a D10 value lower than 0.6 micron.

The present inventors surprisingly also found out that disodium adipate stabilizes chlorinated polyvinylchloride at a particularly efficient extent if fine in particle size. As disodium adipate is particularly useful in solid form providing easier handling, the particle size of the disodium adipate is of peculiar importance.

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. The optional stabilizers or costabilizers can be selected from the group consisting of metal soaps, perchlorates and perfluoroalkanesulphonates, monosodium adipate, antioxidants, alkanolamines, zeolites and hydrotalcites _T polyols, organic phosphites, b-aminocrotonic acid esters and organic co-stabilizers such as dihydropyridines, polydihydropyridines and uracil derivatives.

The optional stabilizer is preferably comprised in the stabilizing composition in a amount in the range from 0.05 to 4 parts by weight per 100 parts of CPVC.

The following can be cited as a non-limiting examples of stabilizers:

Metal soaps

All metal soaps known for use as polyvinyl 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 C-i- C16 alkyl, phenyl- (Ci-Ci6)alkylcarboxylates, naphthyl-(Ci-Ci6)alkylcarboxylates, or phenolates, unsubstituted or substituted with C1-C12 alkyl.

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, 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-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.

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 alkanoates, and preferably Cs-alkanoates, stearates, oleates, laurates, palmitates, behenates, versatates, hydroxystearates, dihydroxystearates, p-tert-butylbenzoates, and 2-ethylhexanoates.

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.

Zn, Li, K, Mg, Ca, Na salts of the aforestated fatty acids containing from 2 to 25 carbon atoms are preferably added to the resin or to the composition/product of the invention. Non-metal stabilizers

Among metal-free stabilizers esters of b-aminocrotonic acid can be cited.

Considered suitable among these compounds are for example b-aminocrotonic acid stearyl ester, 1 ,4-butanediol-di^-aminocrotonic acid) ester, thio-diethanol-b- aminocrotonic acid ester.

Perchlorates and perfluoroalkanesulphonates

The polymer stabilizing composition can also comprise a compound selected from the group consisting of M(CI0 ₄ )k and M(CF3S03)n in which M is selected from the group consisting of H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ , Ba ²⁺ , Zn ²⁺ , Al ³⁺ and NH ₄ ⁺ , and k and n are 1 , 2 or 3 depending on the valency of M.

M is preferably selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ , Mg ²⁺ , Ca ²⁺ and Zn ²⁺ , more preferably M is selected from the group consisting of Na ⁺ , K ⁺ and Ca ²⁺ , and still more preferably it is sodium.

In case of use of a compound of formula M(CF3S03)n, this is preferably trifluoromethanesulphonic acid or a sodium salt thereof, more preferably it being sodium trifluoromethanesulphonate.

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.

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

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 (b-diketones and dihydropyridines or polydihydropyridines, uracil derivatives), alkanolamines, zeolites and hydrotalcites, polyols, hydrates and oxides of alkali and alkaline-earth metals and organic phosphites.

Antioxidants

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 -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or poly-alcohols, esters of -(5-tert-butyl-4-hydroxy-3- methylphenyl)propionic acid with mono- or poly-alcohols, esters of b-(3,5- dicyclohexyl-4-hydroxyphenyl)propionic acid with mono- or poly-alcohols.

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 -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid with octadecanol and with pentaerythritol, respectively Arenox ^® A76 and Arenox ^® A10, produced by Reagens, and bisphenol A.

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 CPVC.

Organic co-stabilizers

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 are preferably one or more compounds selected from dihydropyridines, polydihydropyridines, and uracil derivatives.

Dihydropyridines (DHP). Preferred monomeric dihydropyridine derivatives for use in the present invention include carboxylic acids esters of general formula (II):

wherein Z is CO2C2H5 or C02(n-Ci2H25) and R” is hydrogen, C1 -C18 alkyl, C2-C18 alkoxycarbonyl or Ce-C-io aryl.

Particularly preferred are 3-bisdodecyloxycarbonyl-2,6-dimethyl-1 ,4- dihydropyridine, commercially available as Stavinor ^® D507 (PMC Group).

Uracil derivatives. The uracil derivatives advantageously present in the composition of the invention are described by general formula (III):

wherein:

R ⁴ and R ⁵ are, independently of one another, hydrogen, C1-C12 alkyl, C3-C6 alkenyl, C5-C8 cycloalkyl optionally substituted with 1 to 3 Ci-C ₄ alkyl, Ci-C ₄ alkoxy, Cs-Cs cycloalkyl or hydroxyl or with chlorine atoms, or C7-C9 phenylalkyl optionally substituted on the phenol ring with 1 to 3 Ci-C ₄ alkyl, Ci-C ₄ alkoxy, Cs-Cs cycloalkyl or hydroxyl or with chlorine atoms; Y can be oxygen or sulphur.

Examples of Ci-C ₄ alkyl are methyl, ethyl, n-propyl, isopropyl, n-, iso-, sec-, or tert- butyl.

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

Examples of Ci-C ₄ alkoxy are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy.

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

Examples of C3-C6 alkenyl are allyl, methallyl, 1 -butenyl, or 1 -hexanyl, preferably allyl.

Preferred are the compounds of the aforestated formula, in which R ⁴ and R ⁵ are, each independently of the other, Ci-C ₄ alkyl and hydrogen; in particular, the compound in which R ⁴ and R ⁵ are methyl is preferred.

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

(HI’)

wherein:

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

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

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.

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 CPVC.

Alkanolamines

Alkanolamines, advantageously present in the composition of the invention, are compounds of general formula (IV):

wherein

x = 1 , 2, 3;

y = 1 , 2, 3, 4, 5 or 6;

n is from 1 to 10

R ¹ and R ² are independently H, C1-C22 alkyl,

C2-C20 alkenyl, C2-C18 acyl, C ₄ -Cs cycloalkyl, which can also be hydroxyl- substituted in position b, Ce-C-io aryl, C7-C10 arylalkyl or alkylaryl, or

if x = 1 , then R ¹ and R ² can 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 R ¹ can additionally be C2-C18 alkylene, which can be hydroxyl- substituted at both carbon atoms in b and/or can be interrupted by one or more NR groups;

R _a ³ , Rb ³ are independently C1-C22 alkyl, C2-C6 alkenyl, Ce-C-io aryl, H or CH2-X-R ⁵ , where X is oxygen, sulphur, -O-CO- or CO-O-;

R ⁴ is C1-C18 alkyl, alkenyl or phenyl and

R ⁵ is H, C1-C22 alkyl, C2-C22 alkenyl, or Ce-C-io aryl.

Preferred trialkanolamines of general formula (IV) are those in which R _a ³ , Rb ³ are, each independently of the other, H or methyl, and y = 1.

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, R ¹ is 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.

Examples of preferred alkanolamines according to the general formula are: tri(hydroxyethyl)amine, tri(hydroxypropyl)amine.

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.

Hvdrotalcites

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

[M ²⁺ i-xM ³⁺ x(0H)2] ^x+ [A ⁿ - _x/n mH20] ^x - wherein M ²⁺ represents at least one bivalent metal cation of the group consisting of Mg, Zn, Ni, Ca; M ³⁺ represents at least one trivalent metal cation of the group consisting of Al, Fe; A ⁿ is an anion having a valency comprised between 1 and 4; x and m represent positive numbers which satisfy the following expressions 0.2 < x < 0.33 and

m > 0.

In the general formula above, A ⁿ represents an anion selected from the group consisting of CO3 ² , OH , HCO ³ , CIO ⁴ , NO ³ , I , [Fe(CN)6] ⁴ , acetate, salicylate, tartrate (bivalent) and oxalate (bivalent).

The preferred hydrotalcites of the invention are those in which A ⁿ is selected from COs ² , OH .

The preferred empirical formulas for hydrotalcite considered for the invention are:

Mg ₆ Al2(0H)i6C03-4H20

Mg ₄ Al2(0H)i2C03-3H ₂ 0

Zeolites

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

Mq/a[(AI02)q(Si02)r]'WH20

in which a is the charge on the cation M,

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.

The preferred zeolites, optionally present in the composition of the invention, are described in“Atlas of Zeolite Structure Types”, W. M. Meier and D. H. Olson, Butterworths, 3rd Edition, 1992.

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

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.

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:

Nai2Ali2Sii20 ₄₈ -27H20.

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.

Polyols

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.

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

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

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 which the radicals R are identical or different and selected from C6- C18 alkyl, Ce-C-is alkenyl, phenyl, mono- or di-alkylphenyl, or C5-C7 cycloalkyl.

Phosphites with the following general formula can also be present in the composition of the invention: in which R ¹ and R ² are 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 R ¹ , R ² = stearyl or

Phosphites with the following general formula can also be present:

(R ¹ 0) ₂ -P0-R ² -0P— (OR ³ ) ₂ wherein R ¹ and R ³ are identical or different and are Ce-C-is alkyl, Ce-C-is alkenyl, phenyl, mono- or di-alkylphenyl, or C5-C7 cycloalkyl, R ² is alkyl, alkyloxy, aryl or aryl alkyl.

Each Ce-C-is 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.

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-i5 alcohol) phosphite, bis(2,4-di-t-butylphenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite.

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 CPVC.

In a preferred embodiment of the invention the stabilizing composition consists of disodium adipate in an amount above 0.3 parts by weight per 100 parts of chlorinated polyvinylchloride and no other stabilizers or co-stabilizers are used. The halogenated resin of the invention can be in a rigid, semirigid and plasticized formulation.

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

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

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 CPVC. The final products article can be any type of CPVC product, which needs an enhanced thermal stabilization, for example: extruded and injection molded articles, rigid and semirigid films, sheets, profiles, automotive parts. The articles may be manufactured by any process available to those of ordinary skill in the art including, but not limited to, extrusion, injection molding, compression molding, thermoforming, slush molding.

In another aspect the invention relates to the use of disodium adipate in an amount of above 0.3 parts by weight per 100 parts of polymer for stabilizing chlorinated polyvinylchloride in absence of tin stabilizers.

The invention will be now detailed by illustrative and non-limitative examples

Experimental part

Examples 1-7

All starting materials were commercially available.

Main Ingredients:

Chlorinated polyvinylchloride (CPVC) Disodium adipate

CPVC was available from Sekisui, Kaneka, Kern One as Sekisui HA-58K, Kaneka H829F, Kern One RB 1 167, Kern One RB 8065, Kern One RB 8067, Sekisui HA- 24KL

Disodium adipate was available from Reagens S.p.A. and had the following particle size by volume density as measured by a Malvern Metasizer 3000 equipped with Aero S accessory for powder analysis:

The resin formulation contained the above specified further main ingredients and ingredients in the amounts, expressed as parts by weight per 100 parts by weight of CPVC (phr), as summarized in the following Table 1 :

Table 1 : resin formulation (I) according to the invention for Examples 4-7

Formulations indicated with (C) were a comparative ones (Examples 1 ,2 and 3) and contained the same ingredients as Formulation (I) of the invention other than the amount of disodium adipate as it will be evident from the Table 2 below.

Formulations (I) and (C) were two roll milled to obtain 0.3-0.5 mm sheets, for 3 minutes at 190°C. Rectangular samples (1.5x24 cm) were cut from each sheets. The following tests were used.

Test for the evaluation of thermal stabilization:

The sheets were submitted to heating at 200 °C in glass tubes according to the well-known Congo Red test until color change to red of an indicator paper placed on top of the tubes due to the evolution of HCI triggered by the chlorinated resin degradation. According to this rule, the higher the time to color change to red the better the thermal stabilization. This test, as it was performed on thermoformed samples at high temperature was representative of the long term thermal stabilization of the processing of Chlorinated polyvinylchloride.

Test for the evalution of VICAT:

VICAT softening temperature was evaluated according to ISO306 on 2 mm compression molded plaques of the tested formulations

This test, as it was performed on thermoformed samples at high temperature was representative of the VICAT temperature of chlorinated polyvinylchloride samples (CPVC).

Test for the evaluation of fusion:

In order to evaluate the fusion, the reology behavior of the formulations (C) and (I) was evaluated.

The rheology was evaluated with a Brabender PL2100/3 torque rheometer fitted with a W50EH roller mixer head at 190°C, 40 rpm and 62 g sample formulation as in Table 1 for 8 minutes. Time to fusion was the time to maximum torque that indicated the fusion time.

This test, as it was performed on high temperature processing with rotors similar to the ones of an extruder was representative of the fusion behavior in an extruder of chlorinated polyvinylchloride (CPVC) added with disodium adipate.

The results for Resin formulations (I) and (C) are reported in the following table 2 together with the amounts of disodium adipate

Formulations according to the present invention in Table 2 fulfill all the following desirable features:

-Congo red stability > 53 min. This value is the minimum value in order to obtain a chlorinated resin formulation capable to withstand the industrially used processing procedure;

-VICAT > 82°C;

-Time to fusion < 78 sec. This value is the maximum value in order to obtain a chlorinated resin formulation capable to provide good quality articles.

The formulations of the inventions (I) hence allow obtaining a stabilized CPVC formulations with short fusion time also in absence of tin stabilizers.

Examples 8-9

Evaluation of disodium adipate with the following different particle size (obtained with a Malvern Metasizer 3000 equipped with Aero S accessory for powder analysis) was run according to the experimental procedures described in Examples 1 -7:

The results are reported in the following table:

As shown from the above results, both the compositions according to Example 8 and 9 achieve a suitable Congo Red stability in order to obtain a chlorinated resin formulation capable to withstand the industrially used processing procedure. At the same time, it can be noticed that the use of disodium adipate with finer a particle size (example 8) allow obtaining a stabilized CPVC formulation with an even higher thermal stability, also in absence of tin stabilizers, thus demonstrating the relevance of the particle size of the disodium adipate and the preferability of a particle size showing a D90 value lower than 32.0 micron, a D50 value lower than 9.6 micron and a D10 value lower than 0.8 micron.

Examples 10- 1 1

Evaluation of disodium adipate and disodium succinate with analogue particle size as disodium adipate 1 was run according to the experimental procedures described in Examples 1 -7.

The results are reported in the following table:

As shown from the above results, in example 10 a stabilized CPVC formulation with higher thermal stability, also in absence of tin stabilizers, is obtained, compared to example 1 1 , where a stabilizing formulation based on disodium succinate was used. This demonstrates the importance of the anion of the sodium salt in the stabilizing composition.