WO2008023249A1 - Polyvinylchloride composition - Google Patents

Abstract

ABSTRACT This invention relates to a polyvinylchloride (PVC) composition for use in PVC pipes, which is environmentally friendly and has smoke-suppressant properties. The PVC composition includes an organic based stabilizer (OBS) and a smoke suppressant, which are synergistic in reducing smoke and toxic gas (HCl) emission in the event of the PVC composition combusting.

Description

POLYVINYLCHLORIDE COMPOSITION

BACKGROUND OF THE INVENTION

THIS invention relates to a polyvinylchloride (PVC) composition

PVC is a commodity polymer, developed in the late 1800s and first patented in 1912. Despite many attempts to reduce its consumption over the years, mainly due to ecological reasons, it remains one of the most used polymers today, and around 200 thousand tonnes are consumed in South Africa per annum.

The largest application for PVC in South Africa is for rigid pipe, fittings and profiles. The main end uses are in underground mines and in domestic building applications, where fire and smoke are considered safety hazards. Although, as a polymer PVC is inherently flame retardant due to its high content of chlorine atoms, unfortunately as a result PVC decomposes with the formation of smoke and hydrogen chloride (HCI).

HCI is naturally evolved when PVC is heated according to the following scheme:

-

The HCI evolved in the first step acts to initiate further loss, which unchecked proceeds to loss of all of the chlorine as HCI.

Under fire conditions, in addition to rapid evolution of HCI, PVC formulations emit copious amounts of black smoke. It has been shown (Mulliner et al, Heavy Metal Free PVC Compounds for Cables, paper presented at the PVC1999 Conference, Brighton) that this smoke is a result of formation of benzenoid structures from the degraded PVC after dehydrochlorination has occurred, as shown in the following schematic:

etc.

+ char

It is an object of this invention to provide a PVC composition, particularly for use in PVC pipes that has improved smoke and HCI suppressant properties. SUMMARY OF THE INVENTION

This invention relates to a PVC composition, particularly for use in PVC pipes, the composition including an organic based stabilizer (OBS), typically based on a uracil compound, and a smoke suppressant.

The OBS and smoke suppressant are present in amounts which are synergistic in reducing smoke and HCI emission in the event of the PVC composition combusting.

The OBS may include a compound of the Formula 1 :

O

wherein:

Y is O or S; and

Ri, R₂, and R₃ are monovalent substituents selected from the group consisting of hydrogen, halogen, hydroxyl, alkyl, aryl, aralkyl, acyl, amino, aminoalkyl, aminoaryl, and hydrazine

Preferably, Y is O; R₁ and R₂ are alkyl, phenyl or hydrogen; and R₃ is an electron-donating group. -A-

The organic based stabiliser is preferably a combination of A) at least one compound of Formula I:

O

wherein:

R₃ Is NH_2,

R₁ and R₂ are each independently of the other CVCi₂ alkyl, C₃-Ce alkenyl,

C₅-C₈ cycloalkyl that is unsubstituted or substituted by from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or by chlorine atoms, or C₇-C₉ phenylalkyl that is unsubstituted or substituted at the phenyl ring from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or chlorine atoms, and R₁ and R₂ may additionally be hydrogen and C₁-C₁₂ alkyl, and

Y is S or O;

and B) at least one compound selected from the group consisting of perchlorate compounds, glycidil compounds, beta-diketones and beta-keto esters, dihydropyridines and polydihydropyridines, polyols and disaccharide alcohols, sterically hindered amines (tetraalkylpiperidine compounds), alkali aluminosilicates, hydrotalcites and alkali aluminocarbonates (dawsonites), alkali(or alkaline earth-) carboxylates, -(bi)carbonates or hydroxides, antioxidants, lubricants or organotin compounds which are suitable for stabilising chlorine-containing polymers, especially PVC. The smoke suppressant is preferably heavy-metal free and based on a magnesium / zinc complex oxide of the general formula (Mg₇Zn)O, containing typically 60% as MgO and which is free of Antimony.

Typically, the ratio of OBS to smoke suppressant is from 1 :2 to 1 :1 (by mass).

The OBS typically comprises 1-3, preferably 1-2 phr of the PVC composition and the smoke suppressant typically comprises 1-4, preferably 1-2 phr of the PVC composition.

Preferably, the PVC composition excludes acid scavengers such as calcium stearate, carbonate, oxide or hydroxide, magnesium stearate, carbonate or hydroxide, or zinc stearate or hydroxide.

The invention also relates to a method of manufacturing a stabilised PVC product, the method including the steps of mixing PVC and OBS until the mixture reaches a temperature from 10O⁰C to 12O⁰C, cooling the mixture to a temperature below 6O⁰C, typically about 40⁰C, and then adding a smoke suppressant to the cooled mixture.

The composition of the stabilised PVC product is as described above.

DESCRIPTION OF PREFERRED EMBODIMENTS

This invention relates to a PVC composition, particularly for use in PVC pipes, which is both environmentally friendly and has smoke-suppressant properties, includes an organic based stabilizer (OBS) and a smoke suppressant, which are synergistic in reducing smoke and toxic gas (HCI) emission in the event of the PVC composition combusting. Organic Based Stabilizer (OBS)

The OBS may include a compound of the Formula 1 :

O

wherein Y is O or S, preferably O₁ and R₁, R₂, and R₃ are monovalent substituents selected from the group consisting of hydrogen, halogen, hydroxyl, alkyl, aryl, aralkyl, acyl, amino, aminoalkyl, aminoaryl, and hydrazino. These compounds are described in more detail in US 3,436,362, the content of which is incorporated herein by reference.

The OBS used in this invention is preferably that described in US 5,925,969 (the content of which is incorporated herein by reference). A description of the OBS, from the specification of US 5,925,969 is provided below: The OBS is preferably a combination of A) at least one compound of Formula 1 :

O

wherein: R₃ is NH₂

Ri and R₂ are each independently of the other C₁-C₁₂ alkyl, C₃-C₆ alkenyl, C₅-C₈ cycloalkyl that is unsubstituted or substituted by from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or by chlorine atoms, or C₇-C₉ phenylalkyl that is unsubstituted or substituted at the phenyl ring from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or chlorine atoms, and R₁ and R₂ may additionally be hydrogen and Ci-C₁₂ alkyl, and Y is S or O;

and B) at least one compound selected from the group consisting of perchlorate compounds glycidil compounds, beta-diketones and beta-keto esters, dihydropyridines and polydihydropyridines, polyols and disaccharide alcohols, sterically hindered amines (tetraalkylpiperidine compounds), alkali aluminosilicates, hydrotalcites and alkali aluminocarbonates (dawsonites), alkali(or alkaline earth-) carboxylates, -(bi)carbonates or hydroxides, antioxidants, lubricants or organotin compounds which are suitable for stabilising chlorine-containing polymers, especially PVC.

For compounds of Formula 1 :

C₁-C₄ Alkyl is, for example: methyl, ethyl, n-propyl, isopropyl, n-, iso- , sec- or tert-butyl.

C₁-C₁₂ Alkyl is, for example, in addition to the radicals just mentioned, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, isooctyl, decyl, nonyl, undecyl or dodecyl.

C₁-C₄ Alkoxy is, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy or isobutoxy.

C₅-C₈ Cycloalkyl is, for example, cyclopentyl, cyclohexyl, cycloheptyl or cyclooctyl.

C₇-C₉ Phenylalkyl is, for example, benzyl, 1- or 2-phenylethyl, 3- phenylpropyl, α,α-dimethylbenzyl or 2-phenylisopropyl, preferably benzyl.

When the cycloalkyl groups or the phenyl group of the phenylalkyl radicals are substituted, then they are substituted preferably by two or one substituents and, of the substituents, especially by Cl, hydroxy, methyl or methoxy. C₃ -C₆ Alkenyl is, for example, vinyl, allyl, methallyl, 1-butenyl or 1-hexenyl, preferably allyl.

Preference is given to compounds of Formula I wherein R₁ and R₂ are each independently of the other Ci -C₄ alkyl and hydrogen. Especially preferably, either R₁ and R₂ are identical and are methyl, ethyl, propyl, butyl or allyl, or they are different and are ethyl and allyl.

The compounds of the groups mentioned under B) are illustrated as follows: Perchlorate compounds:

Examples are those of formula M(CIO₄)_n, wherein M is Li, Na, K, Mg, Ca, Sr, Zn, Al, La or Ce. According to the value of M, the index n is 1 , 2 or 3. The perchlorate salts may be complexed with alcohols (polyols, cyclodextrins) or ether alcohols or ester alcohols. The ester alcohols include also the polyol partial esters. Also suitable in the case of polyhydric alcohols or polyols are their dinners, trimers, oligomers and polymers, such as di-, tri-, tetra- and poly-glycols, and di-, tri- and tetra-pentaerythritol or polyvinyl alcohol in various degrees of polymerisation. The perchlorate salts can be introduced in various known forms, for example in the form of a salt or an aqueous solution applied to a substrate, such as PVC, calcium silicate, zeolites or hydrotalcites, or bound in a hydrotalcite by chemical reaction. Glycerol monoethers and glycerol monothioethers are preferred as polyol partial ethers. Other forms are described in EP 394 547, EP 457 471 and WO 94/24200. The perchlorates can be used in an amount of, for example, from 0.001 to 5, advantageously from 0.01 to 3, especially from 0.01 to 2, parts by weight, based on 100 parts by weight PVC.

Glycidyl compounds:

These contain the glycidyl group

which is bonded directly to carbon, oxygen, nitrogen or sulfur atoms and wherein either R₁ and R₃ are both hydrogen, R₂ is hydrogen or methyl and n=0, or R₁ and R₃ together are -CH₂ -CH₂ - or -CH₂ --CH₂ -CH₂ -, in which case R₂ is hydrogen and n=0 or 1.

I) Glycidyl and β-methylglycidyl esters obtainable by reacting a compound having at least one carboxy group in the molecule with epichlorohydrin or glycerol dichlorohydrin or b-methyl-epichlorohydrin. The reaction is advantageously carried out in the presence of bases. Aliphatic carboxylic acids may be used as compounds having at least one carboxy group in the molecule. Examples of those carboxylic acids are glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid or dimerised or trimerised linoleic acid, acrylic acid and methacrylic acid, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid and pelargonic acid, and the acids mentioned in connection with the organic zinc compounds. It is, however, also possible to use cycloaliphatic carboxylic acids, such as cyclohexanecarboxylic acid, tetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4- methylhexahydrophthalic acid. It is also possible to use aromatic carboxylic acids, such as benzoic acid, phthalic acid, isophthalic acid, trimellitic acid or pyromellitic acid. Carboxy-terminated adducts, for example of trimellitic acid and polyols, such as glycerol or 2,2-bis(4-hydroxycyclohexyl)propane can also be used. Other epoxide compounds that can be used within the scope of this invention are to be found in EP 0 506 617.

II) Glycidyl or (β-methylglycidyl) ethers obtainable by reacting a compound having at least one free alcoholic hydroxy group and/or phenolic hydroxy group and a suitably substituted epichlorohydrin under alkaline conditions, or in the presence of an acid catalyst with subsequent treatment with an alkali. Ethers of that 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 C₇-C₉ alkanol and C₉-Cn alkanol mixtures. They are, however, also derived, 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 have 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 phenol, resorcinol or hydroquinone, or they are based on polynuclear phenols, such as bis(4- hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3,5-di bromo-4-hydroxyphenyl)propane, 4,4'-dihydroxydiphenylsulfone, or on condensation products of phenols with formaldehyde obtained under acid conditions, such as phenol novolaks. Other possible terminal epoxides are, for example: glycidyl-1 -naphthyl ether, glycidyl-2-phenylphenyl ether, 2- biphenylglycidyl ether, N-(2,3-epoxypropyl) phthalimide and 2,3- epoxypropyl-4-methoxyphenyl ether.

III) (N-Glycidyl) compounds obtainable by dehydrochlorinating the reaction products of epichlorohydrin with amines containing at least one aminohydrogen atom. Those amines are, for example, aniline, N- methylaniline, toluidine, n-butylamine, bis(4-aminophenyl)methane, m- xylylenediamine or bis(4-methylaminophenyl)methane, but also N₁N₁O- triglycidyl-m-aminophenol or N,N,O-triglycidyl-p-aminophenol. The (N- glycidyl) compounds also include, however, N,N'-di-, N,N',N"-tri and N,N',N",N'"-tetra-glycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1 ,3-propyleneurea, and N,N'-diglycidyl derivatives of hydantoins, such as 5,5-dimethylhydantoin or glycoluril and triglycidyl isocyanurate.

IV) S-Glycidyl compounds, such as di-S-glycidyl derivatives, that are derived from dithiols, such as ethane-1 ,2-dithiol or bis(4- mercaptomethylphenyl) ether.

V) Epoxide compounds containing a radical of formula I wherein R₁ and R₃ together are -CH₂ -CH₂ — 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 containing a radical of formula I wherein R₁ and R₃ together are -CH₂ -CH₂ - and n is 1 is, for example, 3,4-epoxy-6-methylcyclohexanecarboxylic acid (3',4-epoxy- 6'-methylcyclohexyl)-methyl ester. Suitable terminal epoxides are, for example (TMdenotes®): a) liquid diglycidyl ethers of bisphenol A, such as Araldite.TM.GY 240, Araldite.TM.AGY 250, Araldite.TM.GY 260, Araldite.TM.GY 266, Araldite.TM.GY 2600, Araldite.TM.MY 790;

b) solid diglycidyl ethers of bisphenol A, such as Araldite.TM.GT 6071 , Araldite.TM.GT 7071 , Araldite.TM.GT 7072, Araldite.TM.GT 6063, Araldite.TM.GT 7203, Araldite.TM.GT 6064, Araldite.TM.GT 7304, Araldite.TM.GT 7004, Araldite.TM.GT 6084, Araldite.TM.GT 1999, Araldite.TM.GT 7077, Araldite.TM.GT 6097, Araldite.TM.GT 7097, Araldite.TM.GT 7008, Araldite.TM.GT 6099, Araldite.TM.GT 6608, Araldite.TM.GT 6609, Araldite.TM.GT 6610;

c) liquid diglycidyl ethers of bisphenol F, such as Araldite.TM.GY 281, Araldite.TM.PY 302, Araldite.TM.PY 306;

d) solid polyglycidyl ethers of tetraphenylethane, such as CG Epoxy Resin.TM.0163;

e) solid and liquid polyglycidyl ethers of phenolformaldehyde novolak, such as EPN 1138, EPN 1139, GY 1180, PY 307;

f) solid and liquid polyglycidyl ethers of o-cresolformaldehyde novolak, such as ECN 1235, ECN 1273, ECN 1280, ECN 1299;

g) liquid glycidyl ethers of alcohols, such as Shell.TM.glycidyl ether 162, Araldite.TM.DY 0390, Araldite.TM.DY 0391;

h) liquid glycidyl ethers of carboxylic acids, such as Shell.TM. Cardura E terephthalic acid ester, trimellitic acid ester, Araldite.TM.PY 284;

i) solid heterocyclic epoxy resins (triglycidyl isocyanurate), such as Araldite.TM.PT 810;

j) liquid cycloaliphatic epoxy resins, such as Araldite.TM.CY 179;

k) liquid N,N,O-triglycidyl ethers of p-aminophenol, such as Araldite.TM.MY 0510;

I) tetraglycidyl-4,4'-methylenebenzamine or N,N,N',N'-tetraglycidyl- diaminophenylmethane, such as Araldite.TM.MY 720, Araldite.TM.MY 721.

Preference is given to the use of epoxide compounds having two functional groups. It is, however, also possible in principle to use epoxide compounds having one, three or more functional groups. There are predominantly used epoxide compounds, especially diglycidyl compounds, having aromatic groups. Where appropriate, a mixture of different epoxide compounds can also be used. Especially preferred as terminal epoxide compounds are diglycidyl ethers based on bisphenols, such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4- hydroxyphenyl)-methane or mixtures of bis(ortho/para- hydroxyphenyl)methane (bisphenol F). The terminal epoxide compounds can be used in an amount of, preferably, at least 0.1 part, for example from 0.1 to 5, advantageously from 1 to 5 based on 100 parts by weight PVC.

Beta-diketones, beta-keto esters:

1.3-Dicarbonyl compounds that can be used may be linear or cyclic dicarbonyl compounds. Preference is given to the use of dicarbonyl compounds of the following formula:

P₁ CO CHR₂ '-COR's

wherein

• R\ is C_rC₂₂ alkyl, C₅-C₁₀ hydroxyalkyl, C₂-C₁₈ alkenyl, phenyl, phenyl substituted by OH, C₁-C₄ alkyl, C₁-C₄ alkoxy or by halogen, C₇-Ci₀ phenylalkyl, C₅-C₁₂ cycloalkyl, C₅-C₁₂ cycloalkyl substituted by C₁-C₄ alkyl, or is a group --R'₅ -S--R'₆ or -R'₅ -O--R'₆,

• R'₂ is hydrogen, C₁-C₈ alkyl, C₂-C₁₂ alkenyl, phenyl, C₇-C₁₂ alkylphenyl, C₇-Ci₀ phenylalkyl or a group -CO-R₄,

• R'₃ has one of the meanings given for R¹ _! or is C-i -C₁₈ alkoxy,

• R'₄ is C₁-C₄ alkyl or phenyl,

• R'5 is Ci-Ci₀ alkylene and

• R'e is C₁-C₁₂ alkyl, phenyl, C₇-C₁₈ alkylphenyl or C₇-C₁₀ phenylalkyl.

Those compounds include the hydroxy group-containing diketones of EP 346 279 and the oxa- and thia-diketones of EP 307 358, as well as the keto esters based on isocyanic acid of U.S. Pat No. 4,339,383. R'i and R'₃ as alkyl may be, especially, C₁-C₁₈ alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, decyl, dodecyl or octadecyl.

R'i and R'₃ as hydroxyalkyl are, especially, a group — (CH_2)n —OH, wherein n is 5, 6 or 7.

R'-i and R'₃ as alkenyl may be, for example, vinyl, allyl, methallyl, 1- butenyl, 1-hexenyl or oleyl, preferably allyl.

R¹ _! and R'₃ as phenyl substituted by OH, alkyl, alkoxy or halogen may be, for example, tolyl, xylyl, tert-butylphenyl, methoxyphenyl, ethoxyphenyl, hydroxyphenyl, chlorophenyl or dichlorophenyl.

R^ and R'₃ as phenylalkyl are especially benzyl. R'₂ and R'₃ as cycloalkyl or alkylcycloalkyl are especially cyclohexyl or methylcyclohexyl.

R'₂ as alkyl may be, especially, C₁-C₄ alkyl. R'₂ as C₂-C₁₂ alkenyl may be, especially, allyl. R'₂ as alkylphenyl may be, especially, tolyl. R'₂ as phenylalkyl may be, especially, benzyl. R'₂ is preferably hydrogen. R'₃ as alkoxy may be, for example, methoxy, ethoxy, butoxy, hexyloxy, octyloxy, dodecyloxy, tridecyloxy, tetradecyloxy or octadecyloxy. R'₅ as C₁-Ci₀ alkylene is especially C₂-C₄ alkylene. R'₆ as alkyl is especially C₄-Ci₂ alkyl, such as butyl, hexyl, octyl, decyl or dodecyl. R'₆ as alkylphenyl is especially tolyl. R'₆ as phenylalkyl is especially benzyl.

Examples of 1 ,3-dicarbonyl compounds of the above formula and their alkali metal, alkaline earth metal and zinc chelates are acetylacetone, butanoylacetone, heptanoylacetone, stearoylacetone, palmitoylacetone, lauroylacetone, 7-tert-nonylthio-heptane-2,4-dione, benzoylacetone, dibenzoylmethane, lauroylbenzoylmethane, palmitoyl-benzoylmethane, stearoyl-benzoylmethane, isooctylbenzoylmethane, 5-hydroxycapronyl- benzoylmethane, tribenzoylmethane, bis(4-methylbenzoyl)methane, benzoyl-p-chlorobenzoylmethane, bis(2-hydroxybenzoyl)methane, A- methoxybenzoyl-benzoylmethane, bis(4-methoxybenzoyl)methane, 1- benzoyl-1 -acetylnonane, benzoyl-acetylphenylmethane, stearoyl-4- methoxybenzoylmethane, bis(4-tert-butylbenzoyl)methane, benzoyl- formylmethane, benzoyl-phenylacetylmethane, biscyclohexanoyl-methane, di-pivaloyl-methane, 2-acetylcyclopentanone, 2-benzoylcyclopentanone, diacetoacetic acid methyl, ethyl and allyl ester, benzoyl-, propionyl- and butyryl-acetoacetic acid methyl and ethyl ester, triacetylmethane, acetoacetic acid methyl, ethyl, hexyl, octyl, dodecyl or octadecyl ester, benzoylacetic acid methyl, ethyl, butyl, 2-ethylhexyl, dodecyl or octadecyl ester, and propionyl- and butyryl-acetic acid CrC₁₈ alkyl ester. Stearoylacetic acid ethyl, propyl, butyl, hexyl or octyl ester and polynuclear β-keto esters as described in EP 433 230 and dehydroacetic acid and the zinc, magnesium or alkali metal salts thereof.

Preference is given to 1,3-diketo compounds of the above formula wherein R^ is C₁-C₁₈ alkyl, phenyl, phenyl substituted by OH, methyl or by methoxy, C₇-C₁₀ phenylalkyl or cyclohexyl, R'₂ is hydrogen and R'₃ has one of the meanings given for RV

The 1 ,3-diketo compounds can be used in an amount of, for example, from 0.01 to 10, advantageously from 0.01 to 3, and especially from 0.01 to 2, parts by weight, based on 100 parts by weight PVC.

Dihydropyridines, polydihydropyridines:

Suitable monomeric, dihydropyridines are described, for example, in FR 20 39 496, EP 2007, EP 0 362 012, EP 0 286 887 and EP 0 024 754.

Preference is given to those of the formula

wherein Z is CO₂ CH₃, CO₂ C₂ H₅, CO₂" C₁₂ H₂₅ or CO₂ C₂ H₄ Sⁿ C₁₂ H₂₅. Suitable polydihydropyridines are especially compounds of the following formula

wherein T is C₁-C₂₂ alkyl that is unsubstituted or substituted by C₁-Ci₈ alkoxy, C₁-C₁₈ alkylthio, hydroxy, acryloyloxy, methacryloyloxy, halogen, phenyl or by naphthyl;

• C5-C₁₀ aryl that is unsubstituted or substituted by C₁-CiS alkyl, C₁- Ci₈ alkoxy or by halogen and that may also be heterocyclic;

• C₃-C₁₀ alkβnyl, CH₃ -CO-CH₂ -CO-OR'-, CH₃ -CO-CH₂ -COO- R¹, CH₃ -C(NR¹VCH-COOR- or CH₃ -C(NR¹¹¹^=CHCO-OR'-;

• L has the same meanings as T or is a tri- or poly-valent radical from an unsubstituted or Ci -C₁₂ alkoxy-, C₁ -C₁₂ thioalkoxy-, C₆-C₁₀ aryl-, C₁-C₁₂ carboxy- or hydroxy-substituted straight-chained or branched alkyl group,

• m and n are numbers from O to 20,

• k is O or 1 ,

• j is a number from 1 to 6 and the conditions j (k+m+n)>1 and m+n>0 are satisfied,

• R and R' are each independently of the other methylene or phenylene or an alkylene group of the type ~(-C_p H_2p -X-)_t C_p H_2p - - that is unsubstituted or carries substituents from the series C₁-Ci₂ alkoxy, CrCi₂ thioalkoxy, C₆-Ci₀ aryl, Ci-C₁₂ carboxy and hydroxy,

o p is from 2 to 18,

o t is from O to 10,

o X is oxygen or sulfur,

o or, when k is O and j>1 , R and R¹ together with L form a direct bond,

• R" is hydrogen, or C₁-C₁₈ alkyl, C₂-Ci₈ alkoxycarbonyl or C₆-Ci₀ aryl each of which is unsubstituted or substituted by one or more C₁-Ci₂ alkyl, C₁-C₈ alkoxy, halogen or NO₂ substituents, • and the two R¹" radicals are identical or different and are hydrogen, C₁-C₁₈ alkyl, C₁-C₁₈ -hydroxyalkyl or C₁-C₁₈ alkoxyalkyl or together are uninterrupted or O-interrupted C₃-C₅ alkylene,

• or are straight-chained or branched C₂-C₂₂ alkenyl.

Such compounds are described in more detail in EP 0 286 887.

Thiodiethylene-bis[5-methoxycarbonyl-2,6-dimethyl-1 ,4-dihydropyridine- 3-carboxylate] is especially preferred.

The (Poly-)Dihydropyridine can be present in chlorine containing polymer in an amount of from 0,001 to 5 parts and especially 0,005 to 1 parts by weight based on 100 parts by weight PVC.

Polyols, disaccharide alcohols:

Examples of suitable compounds of that type are: pentaerythritol, dipentaerythritol, tripentaerythritol, bistrimethylolpropane, bistrimethylolethane, trismethylolpropane, inosite, polyvinylalcohol, sorbitol, maltite, isomaltite, lactite, lycasin, mannitol, lactose, leucrose, tris(hydroxyethyl) isocyanurate, palatinite, tetramethylolcyclohexanol, tetramethylolcyclopentanol, tetramethylolcyclopyranol, glycerol, diglycerol, polyglycerol, thiodiglycerol or 1-0-α-D-glycopyranosyl-D-mannitol dihydrate.

Of those compounds, preference is given to the disaccharide alcohols.

The polyols can be used in an amount of, for example, from 0.01 to 5, advantageously from 0.1 to 5, parts by weight, based on 100 parts by weight PVC.

Sterically hindered amines (tetraalkylpiperidine compounds): The sterically hindered amines, especially piperidine compounds that can be used according to the invention are known especially as light stabilisers. Those compounds contain one or more groups of the formula

UJC "^"T Jp¹CtU They may be compounds of relatively low molecular weight (<700) or of relatively high molecular weight. In the latter case they may be oligomeric or polymeric products. Preference is given to tetramethylpiperidine compounds having a molecular weight of more than 700 that contain no ester groups.

Especially important as stabilisers are the following classes of tetramethylpiperidine compounds.

In the following classes a) to f), substituents having subscript indices in their formula drawings correspond (for technical reasons) to the substituents having superscript indices in the description or definition belonging to the formula drawing in question. Thus, for example, the substituent "R₁" in formula (II) corresponds to "R¹" in the descriptions. a) Compounds of formula Il

wherein n is a number from 1 to 4, preferably 1 or 2,

• Ri is hydrogen, oxy, C₁-Ci₂ alkyl, C₃-C₈ alkenyl, C₃-C₈ alkynyl, C₇- C₁₂ aralkyl, C₁-C₈ alkanoyl, C₃-C₅ alkenoyl, glycidyl or a group --CH₂ CH(OH)-Z, wherein Z is hydrogen, methyl or phenyl, R¹ being preferably C₁-C₄ alkyl, allyl, benzyl, acetyl or acryloyl, and,

• when n is 1 , R² is hydrogen, C₁-C₁₈ alkyl that is uninterrupted or interrupted by one or more oxygen atoms, cyanoethyl, benzyl, glycidyl, a monovalent radical of an aliphatic, cycloaliphatic, araliphatic, unsaturated or aromatic carboxylic acid, carbamic acid or phosphorus-containing acid or a monovalent silyl radical, preferably a radical of an aliphatic carboxylic acid having from 2 to 18 carbon atoms, a cycloaliphatic carboxylic acid having from 7 to 15 carbon atoms, an α,β-unsaturated carboxylic acid having from 3 to 5 carbon atoms or an aromatic carboxylic acid having from 7 to 15 carbon atoms, and, when n is 2, R₂ is C₁-Ci₂ -alkylene, C₄-Ci₂ alkenylene, xylylene, a divalent radical of an aliphatic, cycloaliphatic, araliphatic or aromatic dicarboxylic acid, dicarbamic acid or phosphorus-containing acid or a divalent silyl radical, preferably a radical of an aliphatic dicarboxylic acid having from 2 to 36 carbon atoms, a cycloaliphatic or aromatic dicarboxylic acid having from 8 to 14 carbon atoms or an aliphatic, cycloaliphatic or aromatic dicarbamic acid having from 8 to 14 carbon atoms, and, when n is 3, R₂ is a trivalent radical of an aliphatic, cycloaliphatic or aromatic tricarboxylic acid, an aromatic tricarbamic acid or a phosphorus-containing acid or a trivalent silyl radical and, when n is 4, R₂ is a tetravalent radical of an aliphatic, cycloaliphatic or aromatic tetracarboxylic acid.

When any of the substituents are C₁-C₁₂ alky!, they are, for example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2- ethyl-hexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.

In the meaning of C₁-C₁₈ alkyl, R² may be, for example, the groups listed above and, in addition, for example, n-tridecyl, n-tetradecyl, n-hexadecyl or n-octadecyl.

When R-_I is C₃-C₈ alkenyl, it may be, for example, 1-propenyl, allyl, methallyl, 2-butenyl, 2-pentenyl, 2-hexenyl, 2-octenyl or 4-tert-butyl-2- butenyl.

R-_I as C₃-C₈ alkynyl is preferably propargyl.

As C₇-C₁₂ aralkyl, R¹ is especially phenethyl and more especially benzyl.

R₁ as C₁-C₈ alkanoyl is, for example, formyl, propionyl, butyryl, octanoyl, but preferably acetyl, and as C₃-C₅ alkenoyl is especially acryloyl.

When R₂ is a monovalent radical of a carboxylic acid, it is, for example, an acetic acid, caproic acid, stearic acid, acrylic acid, methacrylic acid, benzoic acid or β-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid radical. When R₂ is a divalent radical of a dicarboxylic acid, it is, for example, a malonic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, maleic acid, phthalic acid, dibutylmalonic acid, dibenzylmalonic acid, butyl-(3,5di-tert-butyl-4-hydroxybenzyl)-malonic acid or bicycloheptenedicarboxylic acid radical.

When R₂ is a trivalent radical of a tricarboxylic acid, it is, for example, a trimellitic acid or nitrilotriacetic acid radical.

When R₂ is a tetravalent radical of a tetracarboxylic acid, it is, for example, the tetravalent radical of butane-1 ,2,3,4-tetracarboxylic acid or of pyromellitic acid. When R² is a divalent radical of a dicarbamic acid, it is, for example, a hexamethylenedicarbamic acid or a 2,4-toluylene- dicarbamic acid radical.

The following compounds are examples of polyalkylpiperidine compounds of that class:

1 ) 4-hydroxy-2,2,6,6-tetramethylpiperidine

2) 1 -allyl-4-hydroxy-2,2,6,6-tetramethylpiperidine

3) 1-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine

4) 1-(4-tert-butyl-2-butenyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine

5) 4-stearoyloxy-2,2,6,6-tetramethylpiperidine

6) 1 -ethyM-salicyloyloxy^^.e.e-tetramethylpiperidine

7) 4-methacryloyloxy-1 ,2,2,6,6-pentamethylpiperidine

8) 1 ,2,2,6,β-pentamethylpipericlin-4-yl-β-(3,5-di-tert-butyl-4- hydroxyphenyl) propionate

9) di(1-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) maleinate

10) di(2,2,6,6-tetramethylpiperidin-4-yl) succinate

11) di(2,2,6,6-tetramethylpiperidin-4-yl) glutarate

12) di(2,2,6,6-tetramethylpiperidin-4-yl) adipate 13) di(2,2,6,6-tetramethylpiperidin-4-yl) sebacate

14) di(1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate

15) di(1,2,3,6-tetramethyl-2,6-diethylpiperidin-4-yl) sebacate

16) di(1-allyl-2,2,6,6-tetramethylpiperidin-4-yl) phthalate

17) 1 -propargyl-4β-cyanoethyloxy-2,2,6,6-tetramethylpiperidine

18) 1-acetyl-2,2,6,6-tetramethylpiperidin-4-yl acetate

19) trimellitic acid tri(2,2,6,6-tetramethylpiperidin-4-yl) ester

20) 1 -acryloyl-4-ben2yloxy-2,2,6,6-tetramethylpiperidine

21 ) diethylmalonic acid di(2,2,6,6-tetramethylpiperidin-4-yl) ester

22) dibutylmalonic acid di(1 ,2,2,6,6-pentamethylpiperidin-4-yl) ester

23) butyl-(3,5-di-tert-butyl-4-hydroxybenzyl)-malonic acid di(1 ,2,2,6,6pentamethylpiperidin-4-yl) ester

24) dibenzyl-malonic acid di(1 ,2,2,6,6-pentamethylpiperidin-4-yl) ester

25) dibenzyl-malonic acid di(1 ,2,3,6-tetramethyl-2,6-diethyl-piperidin-4- yl) ester

26) hexane-1 \6'-bis(4-carbamoyloxy-1 -n-butyl-2,2,6,6-tetramethyl- piperidine)

27) toluene-2',4^l-bis(4-carbamoyloxy-1 -n-propyl-2,2,6,6- tetramethylpiperidine)

28) dimethyl-bis(2,2,6,6-tetramethylpiperidin-4-oxy)silane

29) phenyl-tris(2,2,6,6-tetramethylpiperidin-4-oxy)silane

30) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl)phosphite

31) tris(1-propyl-2,2,6,6-tetramethylpiperidin-4-yl) phosphate

32) phenyl-[bis(1, 2,2,6, 6-pentamethylpiperidin-4-yl)]phosphonate 33) 4-hydroxy-1 ,2,2,6,6-pentamethylpiperidine

34) 4-hydroxy-N-hydroxyethyl-2,2,6,6-tetramethylpiperidine

35) 4-hydroxy-N-(2-hydroxypropyl)-2,2,6,6-tetramethylpiperidine

36) 1 -glycidyl-4-hydroxy-2,2,6,6-tetramethylpiperidine

b) Compounds of formula (III)

wherein n is the number 1 or 2,

• R-_I is as defined for a),

• R₃ is hydrogen, C₁-Ci₂ alkyl, C₂-C₅ hydroxyalkyl, C₅-C₇ cycloalkyl, C₇-C₈ aralkyl, C₂-Ci₈ alkanoyl, C₃-C₅ alkenoyl or benzoyl, and,

• when n is 1 , R₄ is hydrogen, C₁-Ci₈ alkyl, C₃-C₈ alkenyl, C₅-C₇ cycloalkyl, C₁-C₄ alkyl substituted by a hydroxy, cyano, alkoxycarbonyl or carbamide group, glycidyl, a group of the formula --CH₂ -CH(OH)-Z or of the formula -CONH--Z, wherein Z is hydrogen, methyl or phenyl; and, when n is 2, R₄ is C₂-C₁₂ alkylene, C₆-C₁₂ arylene, xylylene, a -CH₂ -CH(OH)-CH₂ - group or a group -CH₂ -CH(OH)-CH₂ -0-D-O-, wherein D is C₂-C₁₀ alkylene, C₆- Ci₅ arylene or C₆-C₁₂ cycloalkylene, or,

o with the proviso that R₃ is not alkanoyl, alkenoyl or benzoyl,

• R₄ may also be a divalent radical of an aliphatic, cycloaliphatic or aromatic dicarboxylic acid or dicarbamic acid or also the group — CO- or, • when n is 1 , R₃ and R₄ together may be the divalent radical of an aliphatic, cycloaliphatic or aromatic 1 ,2- or 1 ,3-dicarboxylic acid.

When any of the substituents are C₁-C₁₂ - or C₁-C₁₈ -alkyl, they are as already defined above under a).

When any of the substituents are C₅-C₇ cycloalkyl, they are especially cyclohexyl.

As C₇-C₈ aralkyl, R₃ is especially phenylethyl or more especially benzyl. As C₂-C₅ hydroxyalkyl, R₃ is especially 2-hydroxyethyl or 2-hydroxypropyl.

R³ as C₂-C₁₈ alkanoyl is, for example, propionyl, butyryl, octanoyl, dodecanoyl, hexadecanoyl, octadecanoyl, but preferably acetyl, and as C₃- C₅ alkenoyl is especially acryloyl.

When R₄ is C₂-C₈ alkenyl, then it is, for example, allyl, methallyl, 2- butenyl, 2-pentenyl, 2-hexenyl or 2-octenyl.

R₄ as C₁-C₄ alkyl substituted by a hydroxy, cyano, alkoxycarbonyl or carbamide group may be, for example, 2-hydroxyethyl, 2-hydroxypropyl, 2- cyanoethyl, methoxycarbonylmethyl, 2-ethoxycarbonylethyl, 2-aminocarbonylpropyl or 2-(dimethylaminocarbony!)-ethy).

When any of the substituents are C₂-C₁₂ alkylene, they are, for example, ethylene, propylene, 2,2-dimethylpropylene, tetramethylene, hexamethylene, octamethylene, decamethylene or dodecamethylene.

When any of the substituents are C₆-C₁₅ arylene, they are, for example, o-, m- or p-phenylene, 1 ,4-naphthylene or 4,4'-diphenylene.

As C₆-C₁₂ cycloalkylene, D is especially cyclohexylene.

The following compounds are examples of polyalkylpiperidine compounds of that class:

37) N,N^I-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1 ,6- diamine

38) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)hexamethylene-1 ,6- diacetamide and 1 ,6-diformamide

39) 1-acetyl-4-(N-cyclohexylacetamido)-2,2,6,6-tetramethylpiperidine

40) 4-benzoylamino-2,2,6,6-tetramethylpiperidine 41) N,N'-bis(2,2,6,6-tetramethylpiperidrn-4-yl)-N,N'-ctibutyl-adipamicle

42) N,N^I-bis(2,2,6,6-tetramethylpiperidin-4-yl)-N,N^I-dicyclohexyl-2- hydroxypropylene-1 ,3-diamine

43) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)-p-xylylene-diamine

44) N,N'-bis(2,2,6,6-tetramethylpiperidin-4-yl)succine-diamide

45) N-(2,2,6,6-tetramethylpiperidin-4-yl)-β-aminodipropionic acid di(2,2,6,6~tetramethylpiperidin-4-yl) ester

46) the compound of the formula

47) 4-(bis-2-hydroxyethyl-amino)-1 ,2,2,6,6-pentamethylpiperidine 48) 4-(3-methyl-4-hydroxy-5-tert-butyl-benzoic acid amido)-2,2,6,6- tetramethylpiperidine

49) 4-methacrylamido-1 ,2,2,6,6-pentamethylpiperidine c) Compounds of formula (IV)

wherein n is the number 1 or 2,

• R-_I is as defined under a) and,

• when n is 1 , R₅ is C₂-C₈ alkylene or C₂-C₈ hydroxyalkylene or C4-C22 acyloxyalkylene, and, when n is 2, R₅ is the group (~CH₂)₂ C(CH₂ - )₂.

When R₅ is C₂-C₈ alkylene or C₂-C₈ hydroxyalkylene, it is, for example, ethylene, 1-methyl-ethylene, propylene, 2-ethyl-propylene or 2-ethyl-2- hydroxymethylpropylene.

As C₄-C₂₂ acyloxyalkylene, R₅ is, for example, 2-ethyl-2- acetoxymethylpropylene.

The following compounds are examples of polyalkylpiperidine compounds of that class:

50) 9-aza-8,8,10,1Q-tetramethyl-1 ,5-dioxaspiro[5.5]undecane

51 ) 9-aza-8,8, 10, 10-tetramethyl~3-ethyl-1 ,5-dioxaspiro[5.5]undecane

52) 8-aza-2,7,7,8,9,9-hexamethyl-1 ,4-dioxaspiro[4.5]decane

53) 9-aza-3-hydroxymethyl-3-ethyl-8,8,9,10,10-pentamethyl-1 ,5- dioxaspiro[5.5]undecane

54) 9-aza-3-ethyl-3-acetoxymethyl-9-acetyl-8,8,10,10-tetramethyl- 1 ,5dioxaspiro[5.5]undecane

55) 2,2,6,6-tetramethylpiperidine-4-spiro-2'-(1',3^l-dioxane)-5^I-spiro-5"- (rⁱ,3^1I-dioxane)-2"-spiro-4"^I-(2^I",2"^I,6"^I,6^I"-tetramethylpiperidine). d) Compounds of formulae VA, VB and VC

wherein n is the number 1 or 2,

• R-_I is as defined under a),

• R₆ is hydrogen, C_rCi₂ alkyl, allyl, benzyl, glycidyl or C₂-C₆ alkoxyalkyl and,

• when n is 1 , R₇ is hydrogen, C₁-Ci₂ alkyl, C₃-C₅ alkenyl, C₇-C₉ aralkyl, C₅-C₇ cycloalkyl, C₂-C₄ hydroxyalkyl, C₂-C₆ alkoxyalkyl, C₆- Cio aryl, glycidyl or a group of the formula ~(CH₂)_P— COO— Q or of the formula -(CH₂)_p-0-C0~Q, wherein p is 1 or 2 and Q is C_rC₄ alkyl or phenyl, and, when n is 2, R⁷ is C₂ -C₁₂ alkylene, C₄-C₁₂ alkenylene, C₆-C₁₂ arylene, a group --CH₂ -CH(OH)-CH₂ -0-D- CH₂ -CH(OH)-CH₂ --, wherein D is C₂-C₁₀ alkylene, C₆-C₁₅ arylene, C₆-C₁₂ cycloalkylene, or a group -CH₂ CH(OZ')CH₂ -(OCH₂ - CH(OZ')CH₂)₂ - wherein Z¹ is hydrogen, C₁ -Ci₈ alkyl, allyl, benzyl, C₂ -C₁₂ alkanoyl or benzoyl, T-) and T₂ are each independently of the other hydrogen, C₁ -C₁₈ alkyl, or unsubstituted or halo- or C₁-C₄ alkyl-substituted C₆-Ci₀ aryl or C₇-Cg aralkyl, or T₁ and T₂ together with the carbon atom that binds them form a C₅-C₁₂ cycloalkane ring. When any of the substituents are C₁-C₁₂ alkyl, they are, for example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2- ethyl-hexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.

Any substituents having the definition of C₁-C-_I8 alkyl may be, for example, the groups listed above and in addition, for example, n-tridecyl, n- tetradecyl, n-hexadecyl or n-octadecyl.

When any of the substituents are C₂-C₆ alkoxyalkyl, they are, for example, methoxymethyl, ethoxymethyl, propoxy methyl, tert-butoxymethyl, ethoxyethyl, ethoxypropyl, n-butoxyethyl, tert-butoxyethyl, isopropoxyethyl or propoxypropyl.

When R₇ is C₃-C₅ alkenyl, it is, for example, 1-propenyl, allyl, methallyl, 2butenyl or 2-pentenyl.

As C₇-C₉ aralkyl, R, T₁ and T₂ are especially phenethyl or more especially benzyl. When T₁ and T₂ together with the carbon atom form a cycloalkane ring, that ring may be, for example, a cyclopentane, cyclohexane, cyclooctane or cyclododecane ring.

When R⁷ is C₂-C₄ hydroxyalkyl, it is, for example, 2-hydroxyethyl, 2- hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.

As C₆-C₁₀ aryl, _R7, T₁ and T₂ are especially phenyl, a- or β-naphthyl, which are unsubstituted or substituted by halogen or by C₁-C₄ alkyl.

When R⁷ is C₂-C_t2 alkylene, it is, for example, ethylene, propylene, 2,2dimethylpropylene, tetramethylene, hexamethylene, octamethylene, decamethylene or dodecamethylene.

As C₄-Ci₂ alkenylene, R₇ is especially 2-butenylene, 2-pentenylene or 3- hexenylene.

When R₇ is C₆-C₁₂ arylene, it is, for example, o-, m- or p-phenylene, 1 ,4naphthylene or 4,4'-diphenylene.

When Z' is C₂-C₁₂ alkanoyl, it is, for example, propionyl, butyryl, octanoyl, dodecanoyl, but preferably acetyl.

• D as C₂-C₁₀ alkylene, C₆-C₁₅ arylene or C₆-C₁₂ cycloalkylene is as defined under b).

The following compounds are examples of polyalkylpiperidine compounds of that class: 56) 3-benzyl-1 ,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane-2,4-clione

57) 3-n-octyi-1 ,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane-2,4-dione

58) 3-allyl-1 ,3,8-triaza-1 ,7,7,9,9-pentamethylspiro[4.5]decane-2,4-dione

59) 3-glycidyl-1 ,3,8-triaza-7,7,8,9,9-pentamethylspiro[4.5]decane-2,4- dione

60) 1 ,3,7,7,8,9,9-heptamethyl-1 ,3,8-triazaspiro[4.5]decane-2,4-dione

61 ) 2-isopropyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo- spiro[4.5]decane

62) 2,2-di butyl-7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo- spiro[4.5]decane

63) 2,2,4,4-tetramethyl-7-oxa-3,20-diaza-21-oxo-dispiro[5.1.11.2 ]henicosane

64) 2-butyl-7,7,9,9-tetramethyl-1-oxa-4,8-diaza-3-oxo-spiro[4.5]decane

65) 8-acetyl-3-dodecyl-1 ,3,8-triaza-7,7,9,9-tetramethylspiro[4.5]decane- 2,4dione or the compounds of the following formulae:

-continued

e) Compounds of formula Vl

wherein n is the number 1 or 2 and R₃ is a group of the formula

wherein R₁ is as defined under a),

• E is -O- or --NR¹¹ -,

• A is C₂-C₆ alkylene or — (CH₂₎₃ -O- and

• x is the number 0 or 1 ,

• R₉ is identical to R₈ or is one of the groups -NRn Ri₂, -O₁₃, - NHCH₂ OR₁₃ or -N(CH₂ OR₁₃)₂,

• when n=1 , R₁₀ is identical to R₆ or R₉ and, when n=2, R₁₀ is a group -E-B-E-, wherein B is C₂-C₆ alkylene that is uninterrupted or interrupted by -N(R^11)- R_1I is C₁-C₁₂ alkyl, cyclohexyl, benzyl or C₁-C₄ hydroxyalkyl or a group of the formula

R₁₂ is C₁-C₁₂ alkyl, cyclohexyl, benzyl, C₁-C₄ hydroxyalkyl and

R₁₃ is hydrogen, C₁-C₁₂ alkyl or phenyl, or

R₁₁ and R₁₂ together are C₄-C₅ alkylene or C₄-C5 oxaalkylene, for example

are a group of the formula

or alternatively R₁₁ and R₁₂ are each a group of the formula

When any of the substituents are C₁-C₁₂ alkyl, they are, for example, methyl, ethyl, n-propyl, n-butyl, sec-butyl, tert-butyl, n-hexyl, n-octyl, 2- ethylhexyl, n-nonyl, n-decyl, n-undecyl or n-dodecyl.

When any of the substituents are C₁-C₄ hydroxyalkyl, they are, for example, 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl, 2-hydroxybutyl or 4-hydroxybutyl.

When A is C₂-C₆ alkylene, it is, for example, ethylene, propylene, 2,2- dimethylpropylene, tetramethylene or hexamethylene.

When R¹¹ and R¹² together are C₄-C₅ alkylene or C₄-C₅ oxaalkylene, they are, for example, tetramethylene, pentamethylene or 3-oxapentamethylene .

The compounds of the following formulae are examples of polyalkylpiperidine compounds of that class:

wherein R=

, wherein R is

wherein R-

wherein R-

f) Oligomeric or polymeric compounds, the structural repeating unit of which contains one or more 2,2,6,6-tetraalkylpiperidine radicals of formula (I), especially polyesters, polyethers, polyamides, polyamines, polyurethanes, polyureas, polyaminotriazines, poly(meth)acrylates, polysiloxanes, poly(meth)acrylamides and the copolymers thereof that contain such radicals.

Examples of 2,2,6,6-polyalkylpiperidine light stabilisers of that class are the compounds of the following formulae wherein m is a number from 2 to approximately 200.

whereinR_*.

{obtainable by reacting the reaction product of trichlorotriazine and NH₂ ~ (CH₂₎3 -NH-(CHj₀₂ --(CH₂)S -NH₂ with 4-N-butyl-2,2,6,6-tetramethylpiperidine}

Of those classes, classes e) and f) are especially suitable, especially those tetraalkylpiperidine compounds that contain s-triazine groups. Also especially suitable are compounds 74, 76, 84, 87, 92, 95 and 96.

The preparation of the N-piperidinyl-triazines is known from the literature (cf., for example, Houben-Weyl "Methoden der organischen Chemie", Vol. ViII, p. 233-237, 3^rd Ed., Thieme Verlag Stuttgart 1971). There may be used as starting material for the reaction with various N-piperidylamines cyanuric chloride, diamino-chloro-1,3,5-triazine or variously substituted bisdialkylamino-chloro-1 ,3,5-triazines or dialkylamino- or alkylamino- dichloro-1 ,3,5-triazines.

Technically important examples of tetra- and penta-alkylpiperidine compounds are: bis(2,2,6,6-tetramethyl-piperidyl) sebacate, bis(2,2,6,6tetramethyl-piperidyl) succinate, bis(1 ,2,2,6,6-pentamethylpiperidyl) sebacate, n-butyl-S.δ-di-tert-butyl^-hydroxybenzyl-malonic acid bis(1 ,2,2,6,6pentamethylpiperidyl) ester, the condensation product of 1- hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidine and succinic acid, the condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidy()- hexamethyienediamine 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-tetramethyl-piperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy-2,2,6,6-tetramethylpiperidine, bis(1 ,2,2,6,6-pentamethylpiperidyl)-2-n-buty!-2-(2-hydroxy-3,5-di-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, the condensation product of N,N¹-bis(2_>2,6_I6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-rnorpho!ino-2,6-dichloro-1 ,3,5-triazine, the condensation product of 2-chloro-4,6-di(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1 ,3,5-triazine and 1 ,2-bis(3-aminopropylamino)ethane, the condensation product 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, δ-acetyl-S-dodecyl^J.Θ.Θ-tetramethyl-I .S^-triazaspiro^.δJdecane^^- dione, 3-dodecyl-1 -(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione, 3- dodecyl-1-(1 ,2,2,6,6-pentamethyl-4-piperidyl)-pyrrolidine-2,5-dione.

Instead of a single sterically hindered amine, it is possible within the scope of the present invention also to use a mixture of different sterically hindered amines.

The amount of sterically hindered amine added depends on the desired degree of stabilisation. In general, from 0.01 to 0.5% by weight, especially from 0.05 to 0.5% by weight, based on the polymer, is added.

Hydrotalcites and alkali (alkaline earth) aluminosilicates (zeolites): The chemical composition of these compounds is known to a person skilled in the art, for example from patent specifications DE 38 43 581 , U.S.

Pat. No. 40,00,100, EP 062 813, WO 93/20135. Compounds from the hydrotalcite series can be described by general formula VII

M²V_x M³⁺ _x (OH)₂ (A^b-U*αΗ₂ o (VII) wherein

• M²⁺ =one or more of the metals from the group Mg, Ca, Sr, Zn or Sn,

. M³⁺ =AI, or B,

o Aⁿ is an anion having the valency n,

o b is a number from 1 to 2,

• 0<x£ 0.5,and

• m is a number from 0 to 20. Preferably,

• Aⁿ =OH^", CIO₄-, HCO₃-, CH₃ COO^", C₆ H₅ COO^", CO₃ ^2', (CHOHCOO)₂ ^2", (CH₂ COO)₂ ²-, CH₃ CHOHCOO^", HPO₃ ^' or HPO₄ ² -

Examples of hydrotalcites are

• Al₂ O₃.6MgO.CO₂.12H₂ O (i), Mg₄,5 Al₂ (OH)₁₃.CO₃.3.5H₂ O (ii), 4MgO-AI₂ O₃.CO₂.9H₂ O (iii), 4MgO.AI₂ O₃.CO₂.6H₂ O, ZnO.3MgO.AI₂ O₃.CO₂.8-9H₂ O and ZnO.3MgO.AI₂ O₃-CO₂. 5-6H₂ O. Special preference is given to types i, ii and iii.

Zeolites (alkali and alkaline earth aluminosilicates) These can be described by general formula (VIII) M_x/n [(AIO_2)X (SiO₂)_y ].wH₂0(VIII) wherein n is the charge of the cation M;

• M is an element of Group I or Group II, 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

Na₁₂ Al₁₂ Si₁₂ O₄₈. 27 H₂ O [zeolite A]₁ Na₆ Al₆ Si₆ O₂₄. 2 NaX. 7.5 H₂ O,

X=OH, halogen, CIO₄ [sodalite]; Na₆ Al₆ Si₃₀ O₇₂. 24 H₂ O; Na₈ Al₈ Si₄₀ O₉₆.

24 H₂ O; Na₁₆ AIi₆ Si₂₄ O₈₀.16 H₂ O; Na₁₆ AIi₆ Si₃₂ O₉₆.16 H₂ O; Na₅₆ Al₅₆

Si₁₃e 038₄- 250 H₂ O [zeolite Y], Na₈₆ Al₈₆ Si₁₀₆ O₃₈₄- 264 H₂ O [zeolite X];

• or the zeolites that can be formed by partial or complete replacement of the Na atoms by Li, K, Mg, Ca, Sr or Zn atoms, such as

• (Na,K)i₀ Al₁₀ Si₂₂ O₆₄. 20 H₂ O; Ca₄.5 Na₃ [(AIO₂)I₂ (SiO₂)I₂ ]■ 30 H₂ O; K₉ Na₃ [(AIO₂₎₁₂ (SiO₂)₁₂ ]. 27 H₂ O.

Preferred zeolites correspond to the formulae

• Na₁₂ Al₁₂ Si₁₂ O₄₈. 27 H₂ O [zeolite A],

. Na₆ Al₆ Si₆ O₂₄. 2NaX. 7.5 H₂ O, X=OH, Cl, CIO₄, 1/2CO₃ [sodalite]

• Na₆ Al₆ Si₃₀ O₇₂.24 H₂ O,

• Na₈ Al₈ Si₄₀ O₉₆.24 H₂ O,

. Na₁₆ AI₁₆ Si₂₄ O₈₀.16 H₂ O,

• Na₁₆ Al₁₆ Si₃₂ O₉₆.16 H₂ O₁

• Na₅₆ Al₅₆ Si₁₃₆ O₃₈₄. 250 H₂ O [zeolite Y]

• Na₈₆ Al₈₆ Si₁₀₆ O₃₈₄. 264 H₂ O [zeolite X] • and zeolites of the X or Y type possessing an Al/Si ratio of about 1 :1 ,

• or the zeolites that can be formed by partial or complete replacement of the Na atoms by Li, K, Mg, Ca, Sr, Ba or Zn atoms, such as

• (Na₁K)₁₀ Al₁₀ Si₂₂ O₆₄. 20 H₂ O

. Ca₄,5 Na₃ [(AIO₂)₁₂ (SiO₂)₁₂ ]. 30 H₂ O

. K₉ Na₃ [(AIO₂₎₁₂ (SiO₂)₁₂ ]. 27 H₂ O

The zeolites listed may also have a lower water content or may be anhydrous. Other suitable zeolites are:

. Na₂ 0.Al₂ O₃.(2 to 5) SiO₂.(3.5 to 10) H₂ O [zeolite P]

. Na₂ 0.Al₂ O₃.2 SiO₂.(3.5-10)H₂ O (zeolite MAP)

• or the zeolites that can be formed by partial or complete replacement of the Na atoms by Li, K or H atoms, such as

. (Li₁Na₁K₁H)₁₀ Al₁₀ Si₂₂ O₆₄. 20 H₂ O

. K₉ Na₃ [(AIO₂)₁₂ (SiO₂)₁₂ ]. 27 H₂ O

• K₄ Al₄ Si₄ O₁₆.6 H₂ O [zeolite K-F]

Na₈ Al₈ Si₄₀ O₉₆.24 H₂ O zeolite D₁ as described in Barrer et al., J. Chem. Soc. 1952,1561-1571 , and in U.S. Pat. No. 2,950,952; The following zeolites are also suitable:

• potassium offretite, as described in EP-A-400 961;

• zeolite R₁ 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; • Na₃ K₆ Al₉ Si₂₇ O₇₂.21 H₂ 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;

• Na₃₀ Al₃₀ Si₆₆ Oi9₂.98 H₂ O [zeolite ZK-5, zeolite Q].

Special preference is given to the use of zeolite P types of formula I wherein x is from 2 to 5 and y is from 3.5 to 10, especially zeolite MAP of formula I wherein x is 2 and y is from 3.5 to 10, and very especially zeolite Na-P, that is to say M is Na. That zeolite generally occurs in variants Na-P- 1 , Na-P-2 and Na-P-3, which are differentiated by their cubic, tetragonal or orthorhombic structure (R. M. Barrer, B. M. Munday, J. Chem. Soc. A 1971 , 2909-2914). The literature just mentioned also describes the preparation of zeolite P- 1 and P-2. According to that publication, zeolite P-3 is very rare and is therefore of little practical interest. The structure of zeolite P-1 corresponds to the gismondite structure known from the above-mentioned Atlas of Zeolite Structures. In more recent literature (EP-A 384 070) a distinction is made between cubic (zeolite B or P_c) and tetragonal (zeolite P₁₎ zeolites of the P type. That publication also mentions relatively new zeolites of the P type having Si:AI ratios of less than 1.07:1. Those are zeolites designated MAP or MA-P for "Maximum Aluminium P". Depending upon the preparation process, zeolite P may contain small quantities of other zeolites. Very pure zeolite P has been described in WO 94/26662.

Within the scope of the invention it is also possible to use finely particulate, water-insoluble sodium aluminosilicates which have been precipitated and crystallised in the presence of water-soluble inorganic or organic dispersants. Those compounds can be introduced into the reaction mixture in any desired manner before or during the precipitation and/or the crystallisation.

Sodium zeolite A and sodium zeolite P are very especially preferred.

The hydrotalcites and/or zeolites can be used in amounts of, for example, from 0.1 to 10 parts by weight, based on 100 parts by weight of halogen-containing polymer.

Alkali aluminocarbonates (dawsonites) These are compounds of the formula

. {(M₂ O)_m.(AI₂ O₃)_π.Z₀.pH₂ O}, wherein M is H, Li, Na, K, Mgi_/2, Cai_/2, Sri_/2 or Zn_1/2 ; Z is CO₂, SO₂, (Cl₂ Oz)_1Z2, B₄ O₆, S₂ O₂ (thiosulfate) or C₂ O₂ (oxalate): m is a number from 1 to 2 when M is Mg₁^₂ or Ca_1Z2, and in all other cases is a number from 1 to 3; n is a number from 1 to 4; o is a number from 2 to 4; and p is a number from 0 to 30.

The alumino salt compounds of formula (I) that can be used according to the invention may be naturally occurring minerals or synthetically prepared compounds. The metals may partially replace one another. The mentioned alumino salt compounds are crystalline, partially crystalline or amorphous or may be present in the form of a dried gel. The alumino salt compounds may also be present in relatively rare crystalline modifications. A process for the preparation of such compounds is described in EP 394 670. Examples of naturally occurring alumino salt compounds are indigirite, tunisite, aluminohydrocalcite, para-aluminohydrocalcite, strontiodresserite and hydrostrontiodresserite. Other examples of alumino salt compounds are potassium aluminocarbonate ((K₂ O)₁(AI₂ O₃₎.(CO₂₎₂.2H₂ O}, sodium aluminothiosulfate {(Na₂ O). (Al₂ O₃₎.(S₂ O₂₎₂.2H₂ O}, potassium aluminosulfite ((K₂ O)₁(AI₂ O₃₎.(SO₂₎₂.2H₂ O}, calcium aluminooxalate ((CaO)-(AI₂ O₃₎.(C₂ O₂₎₂.5H₂ O}, magnesium aluminotetraborate ((MgO)-(AI₂ O₃J-(B₄ O₆₎₂.5H₂ O}, {([Mg_o.2 Na_o.6 ]₂ O)-(AI₂ O₃₎.(CO₂₎₂.4.1 H₂ O}, {([Mg_o.2 Na_o.6 ]₂ O)₁(AI₂ O₃₎.(CO₂₎₂.4.3H₂ 0} and {([Mg_o-3 Na_o.4 ]₂ O)-(AI₂ O₃₎.(CO₂₎₂.2.4.9H₂ 0}.

The mixed alumino salt compounds can be obtained in accordance with processes known per se by cation exchange, preferably from the alkali alumino salt compounds or by combined precipitation (see, for example, U.S. Pat. No. 5,055,284).

Preference is given to alumino salt compounds of the above formula wherein

• M is Na or K; Z is CO₂, SO₂ or (Cl₂ O₇) i/2 ; m is 1-3; n is 1-4; o is 2- 4 and p is 0-20. Z is especially CO₂.

Preference is given also to compounds that can be represented by the following formulae: M₂ 0.Al₂ O₃.(CO₂)₂. pH₂ O (Ia) (M₂ O)₂-(AI₂ O₃₎₂.(CO₂)₂.pH₂ O(lb) M₂ 0.(Al₂ O₃₎₂.(CO₂)₂.pH₂ O(lc) wherein M is a metal, such as Na, K, Mg-i/2, Ca-ι/2, Sr-ι/2 or Zn-,/2 and p is a number from O to 12.

Special preference is given to sodium aluminodihydroxycarbonate (DASC) and to the homologous potassium compound (DAPC).

Dawsonites may also be substituted by lithium-alumohydroxycarbonates or lithium-magnesium-alumohydroxycarbonates, as described in EP 549,340 and DE 4,425,266.

The dawsonites can be used in an amount of, for example, from 0.01 to 5, advantageously from 0.1 to 3, especially from 0.1 to 2, parts by weight, based on 10O parts by weight of halogen-containing polymer.

The stabiliser combination preferably comprises component A) and, as component B), at least one substance from the following groups: perchlorate compounds, glycidyl compounds, or dihydropyridines and polydihydropyridines. Other organic based stabilizers are described in more detail in United States Patents Nos. 6,194,494, 6,232,375, and 6,274,654, the contents of which are incorporated herein by reference.

Preferred organic based stabilizers are Mark OBSTM101 and other Mark OBSTM100 series stabilisers available from Chemtura Corporation.

Smoke suppressant

The smoke-suppressant is preferably based on a magnesium/zinc complex oxide of the general formula (Mg₁Zn)O and containing typically 60% as MgO, and which is free of Antimony. The smoke suppressant is specifically considered to be heavy-metal free. The preferred smoke suppressant is Ongard™2 available from Chemtura Corporation.

An object of this invention is to reduce smoke and emission of HCI from PVC.

It has been found that with in PVC compositions of the present invention containing a heavy metal-free smoke suppressant having zinc and/or magnesium, these metals act to prevent the formation of benzenoid structures during thermal decomposition of PVC. In addition the zinc and magnesium in the smoke suppressant act as costabilisers by reaction with HCI to form metallic chlorides.

Further, the OBS, in addition to its primary function as stabilizer, assists with the reduction of smoke due to preventing the formation of benzenes. The heavy metal free smoke suppressant in addition to its primary function as a smoke suppressant assists with heat stability by its reaction with HCI formed during burning. Apart from the fact that the combination of these compounds has not been practiced in the past, it has surprisingly been found the use of these together to be synergistic in reducing the amount of smoke and HCI emitted; and the amount of HCI is reduced in comparison to a PVC composition containing a Pb stabiliser. It has further, most surprisingly, been found that a PVC composition containing the smoke-suppressant based on a magnesium/zinc complex which is heavy metal free does not require the inclusion of "acid scavengers" (i.e. basic compounds that react with HCI to form a metal chloride such as calcium stearate, carbonate, oxide or hydroxide, magnesium stearate, carbonate or hydroxide, or zinc stearate or hydroxide). In fact, the inclusion of such acid scavengers increases the amount of HCI emitted and PVC compositions of the invention exclude such acid scavengers.

The compositions of the invention are environmentally friendly, making use of environmental synergies between organic based stabilizer (based on a uracil compound) and a smoke suppressant (based on a magnesium/zinc complex). In the case of use in the mines the reduction in smoke and HCI emission coupled with absence of heavy metals is desirous. In the case of building applications the use of the combination is also desirous to a more environmentally friendly application.

The organic based stabilizer may be used at 1.5-3% by mass in rigid PVC articles, together with lubricants, fillers and impact modifiers. The smoke suppressant may be used in rigid PVC articles at 1-4% by mass. The synergistic combination of an organic based stabilizer, heavy metal free smoke suppressant/flame retardant and acid scavenger has not been practiced before.

The invention will now be described in more detail with reference to the following non-limiting examples. In the examples, the stabiliser is Mark OBS™101 , and smoke suppressant is Ongard™2, both available from the Chemtura Corporation. The Pb stabiliser was a one-pack containing Tribasic lead sulphate plus lubricants. Example 1

A typical formulation comprised of:

PVC, K Value 67 100 phr#

Stabiliser* 2.5 phr

Titanium dioxide 1.0 phr

Calcium carbonate 2.5 phr

Smoke Suppressant** 2.0 phr

Pigments as required for effect

# parts per hundred PVC resin

* one pack Mark OBS™101 including lubricants ** Ongard2

Method - 100 parts Corvic S6721 were added to a Pappenmeier high speed mixer. The mixer was switched on at low speed (750 rpm) and the stabilizer was added. The mixer was switched to high speed (1500 rpm) and the lubricants added. On reaching a temperature of 120⁰C the mix was dumped to a cooling mixer. Smoke suppressant, fillers and pigments were added and the mix cooled to 40⁰C. It is important that the smoke suppressant is added to the cooling mixer and not to the high speed mixer to avoid discolouration.

Results - Plaques of 75x75x10 mm were compression moulded. The prepared plaques were tested in a Smoke Density Chamber according to ASTM E662 for smoke generation, and ASTM D2863 for flammability as limiting oxygen index. The results are shown in Table 1 below:

Table 1

Example 2

PVC compounds were produced by mixing PVC powder, stabilizer, lubricants and chlorinated polyethylene as impact modifier in a high speed mixer according to the formulations shown. The mix was dropped to a cooler mixer at 110⁰C and cooled to 4O⁰C before processing. The mixes were compression moulded into plaques of 76mm x 76mm x 5mm for further testing.

The resultant plaques were tested for smoke generation by ASTM662 and the smoke density, time to maximum obscuration and the mass loss measured is shown in Table 2 below:

Table 2

The data in Table 2 indicates that increasing the ratio of OBS to Ongard by 10% brings a significant reduction in smoke and increase in time to maximum obscuration. Further, mass loss due to dehydrochlorination is lower in the case of OBS compared to Pb at the same stabilizer level. Accordingly the combination of OBS and Ongard performs better than the combination of the Pb stabiliser and Ongard.

Example 3

The loss of hydrogen chloride was examined in greater detail: 1 ) in comparison to a Pb stabiliser; 2) including HC) scavengers; and

3) as a function of: varying the level of OBS and Ongard 2. Plaques were produced in the same manner as Example 2. The results are provided in Table 3 below:

Conductivity was measured according to IEC 60754-2. 1 mg compound is weighed into a combustion boat which is placed in a furnace and heated to 900⁰C. The gases from the combustion of the PVC, which include HCI are led into a wash bottle containing deionised water. The conductivity of the water is measured after 30 minutes. The higher the conductivity the higher the level of HCI dissolved in the water and consequently emitted from the sample.

Table 3

It is clear from Table 3 that:

1 ) the combination of the OBS and Ongard has lower HCl emissions than a combination of a Pb stabiliser and Ongard;

2) the addition of acid scavengers (MgOH and CaCO₃) leads to an increase in HCI emission; and 3) the best results are obtained where the ratio of OBS to Ongard2 is 1 :2 to 1 :1 (by mass), with amounts of 1-3, preferably 1-2 phr OBS and 1-4, preferably 1-2 phr Ongard 2.

Example 4

The above data was put to use in a commercial scale test. The results of the test are provided in Table 4.

Table 4

1. Pb stabilized commercial pipe without smoke suppressant

2. OBS stabilized with 2 phr Ongard 2

Claims

CLAlMS

1. A PVC composition including an organic based stabilizer (OBS) and a smoke suppressant.

2. The PVC composition according to claim 1 , wherein the OBS is based on a uracil compound.

3. The PVC composition according to claim 2, wherein the OBS includes a compound of the Formula 1 :

O

wherein:

Y is O or S; and

R₁, R₂, and R₃ are monovalent substituents selected from the group consisting of hydrogen, halogen, hydroxyl, alkyl, aryl, aralkyl, acyl, amino, aminoalkyl, aminoaryl, and hydrazino.

4. The PVC composition according to claim 3, wherein Y is O; R₁ and R₂ are alkyl, phenyl or hydrogen; and R₃ is an electron-donating group.

5. The PVC composition according to claim 1 , wherein the organic based stabiliser is a combination of A) at least one compound of Formula I: O

wherein: R₃ is NH₂,

R₁ and R₂ are each independently of the other CrCi₂ alkyl, C₃-C₆ alkenyl, C₅-C₈ cycloalkyl that is unsubstituted or substituted by from 1 to 3 C₁-C₄ alkyl, CrC₄ alkoxy, Cs-C₈ cycloalkyl or by hydroxy groups or by chlorine atoms, or C₇-C₉ phenylalkyl that is unsubstituted or substituted at the phenyl ring from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, Cs-C₈ cycloalkyl or by hydroxy groups or chlorine atoms, and R*i and R*₂ may additionally be hydrogen and C₁-C₁₂ alkyl, and Y is S or O;

and B) at least one compound selected from the group consisting of perchlorate compounds, glycidil compounds, beta-diketones and beta-keto esters, dihydropyridines and polydihydropyridines, polyols and disaccharide alcohols, sterically hindered amines (tetraalkylpiperidine compounds), alkali aluminosilicates, hydrotalcites and alkali aluminocarbonates (dawsonites), alkali(or alkaline earth-) carboxylates, -(bi)carbonates or hydroxides, antioxidants, lubricants or organotin compounds which are suitable for stabilising chlorine-containing polymers.

6. The PVC composition according to any one of the preceding claims, wherein the smoke suppressant is heavy-metal free and based on a magnesium / zinc complex.

7. The PVC composition according to claim 6, wherein the smoke suppressant is based on a magnesium / zinc complex oxide.

8. The PVC composition according to claim 7, wherein the magnesium / zinc complex oxide is of the general formula (Mg₁Zn)O.

9. The PVC composition according to claim 8, wherein the magnesium / zinc complex oxide containing typically 60% as MgO.

10. The PVC composition according to any one of the preceding claims, wherein the ratio (by mass) of OBS to smoke supressant is from 1 :2 to 1 :1.

11. The PVC composition according to any one of the preceding claims, wherein the OBS comprises 1-3 phr of the composition.

12. The PVC composition according claim 11 , wherein the OBS comprises 1-2 phr of the composition.

13. The PVC composition according to any one of the preceding claims, wherein the smoke suppressant comprises 1-4 phr of the composition.

14. The PVC composition according to claim 13, wherein the smoke suppressant comprises 1-2 phr of the composition.

15. The PVC composition according to any one of claims 1 to 14 excluding acid scavengers.

16. A method of manufacturing a stabilised PVC product, the method including the steps of mixing PVC and OBS until the mixture reaches a temperature from 100⁰C to 12O⁰C₁ cooling the mixture to a temperature below 60⁰C, and then adding a smoke suppressant to the cooled mixture.

17. The method according to claim 16, wherein the mixture is a cooled to a temperature of about 40°C before adding the smoke suppressant.

18. The method according to claim 16 or 17, wherein the OBS is based on a uracil compound.

19. The method according to claim 18, wherein the OBS includes a compound of the Formula 1 :

O

wherein:

Y is O or S; and

R-i, R₂, and R₃ are monovalent substituents selected from the group consisting of hydrogen, halogen, hydroxyl, alkyl, aryl, aralkyl, acyl, amino, aminoalkyl, aminoaryl, and hydrazino.

20. The method according to claim 19, wherein Y is O; R₁ and R₂ are alkyl, phenyl or hydrogen; and R₃ is an electron-donating group.

21. The method according to claim 16 or 17, wherein the organic based stabiliser is a combination of A) at least one compound of Formula I:

O

wherein:

R₃Is NH₂,

R₁ and R₂ are each independently of the other Ci-C₁₂ alkyl, C₃-C₆ alkenyl,

C₅-C₈ cycloalkyl that is unsubstituted or substituted by from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or by chlorine atoms, or C₇-C₉ phenylalkyl that is unsubstituted or substituted at the phenyl ring from 1 to 3 C₁-C₄ alkyl, C₁-C₄ alkoxy, C₅-C₈ cycloalkyl or by hydroxy groups or chlorine atoms, and R-i and R₂ may additionally be hydrogen and C₁-C₁₂ alkyl, and

Y is S or O;

and B) at least one compound selected from the group consisting of perchlorate compounds, glycidil compounds, beta-diketones and beta-keto esters, dihydropyridines and polydihydropyridines, polyols and disaccharide alcohols, sterically hindered amines (tetraalkylpiperidine compounds), alkali aluminosilicates, hydrotalcites and alkali aluminocarbonates (dawsonites), alkali(or alkaline earth-) carboxylates, -(bi)carbonates or hydroxides, antioxidants, lubricants or organotin compounds which are suitable for stabilising chlorine-containing polymers.

22. The method according to any one of claims 16 to 21 , wherein the smoke suppressant is heavy-metal free and based on a magnesium / zinc complex.

23. The method according to claim 22, wherein the smoke suppressant is based on a magnesium / zinc complex oxide.

24. The method according to claim 23, wherein the magnesium / zinc complex oxide is of the general formula (Mg₁Zn)O.

25. The method according to claim 24, wherein the magnesium / zinc complex oxide containing typically 60% as MgO.

26. The method to any one of claims 16 to 25, wherein the OBS and smoke suppressant are added at a ratio (by mass) of from 1:2 to 1 :1.

27. The method according to any one of claims 16 to 26, wherein the OBS is added in an amount of 1-3 phr of the composition.

28. The method according claim 27, wherein the OBS is added in an amount of 1-2 phr of the composition.

29. The method according to any one of claims 16 to 28, wherein the smoke suppressant is added in an amount of 1-4 phr of the composition.

30. The method according to claim 29, wherein the smoke suppressant is added in an amount of 1-2 phr of the composition.

31. The method according to any one of claims 16 to 30, wherein no acid scavengers are added to the composition.