# Patent

## Title
Hindered amine light stabilizers for polymers

## Abstract

A stabilizing composition consisting of substituted alpha- or beta-naphthindoles, benzoylated or not benzoylated, and combined with organic polyimines such as those of formula 1 of the formulae sheet, in which R is alkyl or dialkyl, ethoxylated alkylmercaptans with 2.varies.8 ethoxy groups and (metal) halides of barium, calcium, lithium, zinc or aluminum, have a strong thermostabilizing effect on chlorine containing thermoplastics, especially on polyvinyl chloride, both homo-M and S polymers thereof, and on polyvinylidene chloride.

## Background
It is known that chlorine containing thermoplastics, such as e.g. polyvinyl chloride, split off HCl under thermal load, accompanied by discoloration and degradation.

In order to prevent this so-called thermostabilizers are added, the little poisonous and most effective of which are the organotin mercaptides and the dialkyltin carboxylates.

Those detrimental to health comprise the organometallic compounds of strontium, cadmium and lead.

U.S. Pat. No. 3,644,246 discloses a mixture of dialkyltin carboxylates and sodium, magnesium, calcium or aluminum salts of halfesters of unsaturated dicarboxylic acids, e.g. maleic acid. Beside the formation of anhydride at elevated temperatures there is the disadvantage that stabilizers on this base if combined with phosphites cannot be kept.

According to British Pat. Nos. 1,229,521 and 1,229,522 and Japanese Pat. specification No. 4723442 organotin mercaptides containing calcium, magnesium and barium compounds are proposed. However, it is known that such combinations develop a strong odour during processing.

The present invention is characterized in that the stabilizer compositions contain no tin, lead, cadmium or strontium, whereas also unsaturated dicarboxylic acids, such as maleic acid, are completely absent.

During processing at elevated temperatures no volatile, prickling or strongly smelling substances are developed, and yet the chlorine containing thermoplastics have an effective protection against degradation at elevated temperatures.

Furthermore no "plate out" occurs during processing on calanders.

The combination with liquid organic phosphites is readily possible; they can serve as light stabilizer and solvent.

Addition of solvents such as glycols, glycol ethers and aromatic solvents is not advisable as at elevated processing temperatures odour, volatile vapours and gases develop.

Moreover the stabilizing composition of the present invention may contain anti-oxidants, such as sterically hindered alkyl phenols, such as 2,6-di-tert. butyl-4-methylphenol and 4-hydroxymethyl-2,6-di-tert. butylphenol.

Addition of (2,4-di-tert.butylphenyl)-3,5-di-tert.butyl-4-hydroxybenzoate provides in combination with organic phosphites a substantially increased light resistance.

According to the present invention it has been found that a stabilizing composition consisting of substituted alpha- or beta-naphthindoles, benzoylated or not benzoylated, and combined with organic polyimines such as those of formula 1 of the formulae sheet, in which R is alkyl or dialkyl, ethoxylated alkylmercaptans with 2-8 ethoxy groups and (metal) halides of barium, calcium, lithium, zinc or aluminum, have a strong thermostabilizing effect on chlorine containing thermoplastics, especially on polyvinyl chloride, both homo-M and S polymers thereof, and on polyvinylidene chloride.

Also copolymers of vinyl chloride and vinyl acetate, copolymers of ethylene, vinyl chloride and vinyl acetate and copolymers of vinylidene chloride are strongly thermally stabilized by the said stabilizing composition.

It is not necessary that the chlorine containing thermoplastic contains a plasticizer.

Both initial and final stability are excellent, also on long-term keeping.

The substitution of the naphthindoles can be alkyl or aryl or combinations of both, whereas also hydroxy, methoxy and ethoxy groups may be present.

Isostearic acid and isostearic acid esters or mixtures thereof may serve as solvent, possibly combined with organic phosphites. If used they also serve as lubricant (vide Belgian Pat. specification No. 872,794) and give the end-product (film or bottle) a strong anti-blocking and anti-sticking effect, whereas to products containing a plasticizer they provide the effect of improved hand and drape.

Metal salts of isostearic acid act strongly as internal and external lubricant. Especially the lithium salt of isostearic acid gives particularly glass-clear film and bottles in combination with benzoylated substituted naphthindoles, polybutyl imine, zinc chloride and an ethoxylated tert.dodecylmercaptan with 4,5 ethoxy groups. Thermal stability is excellent herewith.

Example of a synthesis for some substituted naphthindoles:

A mixture of 468 g (6,5 moles) methyl ethyl ketone and 1500 cc water was heated at 60.degree. C. with nitrogen being passed through, after which 960 g (6.0 moles) bromine was added thereto by dripping. After the end of the reaction the separated oil was washed subsequently with water, sodium bicarbonate solution and water, and finally dried over calcium chloride. After fractional distillation with the aid of a long Vigreux column or Widmer spiral 350 g of a colourless oil, boiling at 45.degree.-47.degree. C./19 mm Hg, was obtained.

138 g of methyl alpha-bromoethyl ketone and 275 g of alpha-naphthylamine (molar ratio 1:2.05) were solved together in 500 ml of 96% ethyl alcohol and boiled for 8 hours. Then, while boiling, water was added to the mixture, until it just started to become turbid. Upon cooling down the naphthindole crystallized. It was filtrated by suction and for purification it was once boiled up with diluted HCl. After filtration by suction and drying 169 g of substantially pure naphthindole (yield 94%) resulted. For obtaining a 100% pure product one may recrystallize from a mixture of benzene and petroleum ether. In that case white silver-glossy leaflets are formed, melting at 150-151.degree. C.

In an analogous way, starting from beta-naphthylamine, 2,3-dimethyl-beta-naphthindole, melting at 131.degree.-132.degree. C., can be obtained in a yield of 72%. During the reaction a slight resinification occurs. Therefore, after the reaction only a small amount of water should be added, whereupon an amount of resin separates, which should be filtrated by suction first, before more water is added to the alcoholic solution until turbidity occurs, after which, upon cooling, the beta-naphthindole separates in the form of colorless hard crystals.

Benzoyl chloride was dripped slowly into a solution of 2,3-dimethyl-alpha-naphthindole. After completion of the addition nitrogen is passed through and the temperature is raised slowly until boiling, whereby the remaining HCl is driven off. The toluene is distilled off under vacuum and ethyl alcohol is added, in which the mass dissolves readily, after which water is added until turbidity occurs. After cooling down the product crystallizes.

In this case in an analogous manner 2,3-di-methyl-beta-naphthindole is benzoylated in solution. Also in this case the solvent is toluene and the recrystallization is carried out in a mixture of ethyl alcohol and water. --CH.sub.2 --)

Commercial butyraldehyde (a by-product of the production of synthetic rubber) having a density of 0,82  g/cm.sup.3, containing 6-7% of acetaldehyde and propionaldehyde and for 75-80% consisting of a mixture of butyraldehyde and isobutyraldehyde, the remainder consisting of water, butanol and minor quantities of higher alcohols and aldehydes, is saturated with NH.sub.3 gas. The reaction product separates into two layers. The upper layer consists of the aldehyde/ammonia, which has a typical odour and is viscous. The lower layer consists of water, containing butyl and other alcohols. The separated butyraldehyde/ammonia is heated at 110.degree. C. for 2-3 hours, during which the viscosity increases by polymerisation of the butyrimine formed.

Example of a synthesis of ethoxylated tert. dodecyl mercaptan, C.sub.12 H.sub.25 S(CH.sub.2.CH.sub.2.O).sub.n H, in which n=2-8.

202 kg of dry tert.dodecyl mercaptan and 1 kg of solid KOH, ground to powder, are put into a stainless steel pressure kettle (6 atm), provided with a blade agitator revolving at 500 r.p.m. and a heating jacket up to 8 atm. for steam heating and water cooling, respectively. The exthylene oxyde is introduced from below into the bottom of the kettle by means of a stainless steel pipe. The introduction can be monitored by means of a looking glass. The tert.dodecyl mercaptan is heated at 130.degree. C. under introduction of nitrogen in order to expel the air. Hereafter the kettle is closed, and addition takes place of: (a) for 2 ethoxy groups 88 kg of ethylene oxide (b) for 4 ethoxy groups 176 kg of ethylene oxide (c) for 7 ethoxy groups 308 kg of ethylene oxide ______________________________________

The pressure as maintained at 0.8-1.2, atm., optionally the temperature is allowed to rise to 150.degree. C. After the reaction neutralisation is carried out with propionic acid. Duration of the reaction is about 3-4 hours, depending on the amount of ethylene oxide added. Practically quantitative yield. Stabilizer M1 ______________________________________ Zinc chloride, anhydrous 105 g Water                  35 g 2-Ethoxy-tert.dodecyl mercaptan 200 g 7-Ethoxy-tert.dodecyl mercaptan 230 g Isostearic acid       430 g ______________________________________

The zinc chloride is solved in the amount of water and mixed under agitation with the 7-ethoxy-tert.dodecyl mercaptan, after which the 2-ethoxy-tert. dodecyl mercaptan and the isostearic acid are added successively under agitation. A clear light yellow liquid is obtained. Stabilizer M2 ______________________________________ Zinc chloride, anhydrous 80 g Lithium chloride, anhydrous 35 g Water                  60 g 2-Ethoxy-tert.dodecyl mercaptan 200 g 7-Ethoxy-tert.dodecyl mercaptan 230 g Isostearic acid       430 g ______________________________________

The zinc chloride and the lithium chloride are solved in the amount of water and mixed with the 7-ethoxy-tert.dodecyl mercaptan under agitation, after which subsequently the 2-ethoxy-tert.dodecyl mercaptan and the isostearic acid are added under agitation. A clear light yellow liquid is obtained. Stabilizer M3 ______________________________________ Zinc chloride, anhydrous 80 g Barium chloride, anhydrous 35 g Water                  62 g 2-Ethoxy-tert.dodecyl mercaptan 200 g 7-Ethoxy-tert.dodecyl mercaptan 230 g Isostearic acid       430 g ______________________________________

Same procedure as M2. Stabilizer M4 ______________________________________ Aluminum chloride, anhydrous 80 g Calcium chloride, anhydrous 35 g Water                  60 g 2-Ethoxy-tert.dodecyl mercaptan 200 g 7-Ethoxy-tert.dodecyl mercaptan 230 g Isostearic acid       430 g ______________________________________

Liquid stabilizing composition for rigid P.V.C., e.g. bottles. Addition: 6.7-7 kg per 100 kg of P.V.C., k-value 55/60. Epoxy soy bean oil         3400   g Trinonyl-phenyl phosphite  600    g Calcium isostearate        300    g Glycerol monoisostearate   250    g Pentaerithritol mono-p-tert.butyl benzoate triisostearate             1200   g Pentaerithritol trimontanate monoisostearate 300    g Wax AC 316, Allied Chemicals (polyethylene wax)                       50     g Benzoyl-2,3-dimethyl-alpha-naphthindole 50     g Polybutyl imine            150    g Stabilizer M1              300    g Isostearic acid            100    g ______________________________________

Heat at 90.degree. under agitation and passing through of nitrogen, until everything has been solved, then cool again to 40.degree. C., after which it is ready for use.

Liquid stabilizing composition for rigid P.V.C., e.g. film and bottles. Per 100 kg of PVC also 8 kg of modified Kane Ace B 28 (MBS) is added, as an impact resistance component. Addition: as in Example I. Epoxy soy bean oil         3400   g Trinonyl-phenyl phosphite  600    g Calcium isostearate        300    g Pentaerythritol monoisostearate 600    g Pentaaerythritol di-p-tert.butyl benzoate diisostearate              600    g Butane-1,4-diol monomontanate monoisistearate 300    g Wax AC 316                 50     g 2,3-Dimethyl-alpha-naphthindole 100    g Polybutyl imine            100    g Stabilizer M2              300    g Isostearic acid            80     g ______________________________________

Procedure as described in Example I.

Liquid stabilizing composition for rigid P.V.C., especially for injection molding purposes. Per 100 kg of P.V.C., k-value 55/60, 6.7-7 kg of stabilizing composition and 8 kg of Kane Ace B 28 impact resistance component are used. Epoxy soy bean oil        3400   g Trinonyl-phenyl phosphite 600    g Calcium isostearate       300    g Trimethylolpropane monoisostearate 250    g Pentaerythritol tri-p-tert.butylbenzoate monoisostearate           1200   g Pentaerythritol dimontanate diisostearate 300    g Wax AC 316                50     g Benzoyl-2,3-dimethyl-alpha-naphthindole 50     g Dimethyl-beta-naphthindole 25     g Polybutyl imine           275    g Stabilizer M3             300    g Isostearic acid           100    g ______________________________________

Procedure as described in Example I.

Liquid stabilizing composition for soft P.V.C., suitable for film and injection molding articles. Per 100 kg of P.V.C., k-value 68/72, 4.2-5 kg of the present stabilizing compositions and 50 kg of dioctyl adipate are added. Epoxy soy bean oil         1000   g Diphenyl-myristyl phosphite 400    g Calcium isostearate        300    g Glycerol monostearate      250    g Pentaerythritol tetraisostearate 1200   g Pentaerythritol trimontanate monoisostearate 300    g Isostearic acid            250    g Benzoyl-2,3-dimethyl-alpha-naphthindole 100    g Stabilizer M4              300    g Polybutyl imine            150    g ______________________________________

Procedure as described in Example I.

Liquid stabilizing composition for soft P.V.C., suitable for film, injection molding and plastisols. Per 100 kg of P.V.C., k-value 70/72, 4.4-5 kg of the present stabilizing composition is added. Epoxy soy bean oil         1000   g Diphenyl-myristyl phosphite 600    g Lithium isostearate        300    g Glycerol monostearate      250    g Pentaerythritol tetraisostearate 1200   g Pentaerythritol trimontanate monoisostearate 300    g Isostearic acid            250    g Benzoyl-2,3-dimethyl-beta-naphthindole 50     g 2,3-Dimethyl-alpha-naphthindole 25     g Polybutyl imine            150    g Stabilizer M2              300    g Stabilizer M2 (2,4-di-tert.butylphenyl)-3,5-di-tert.butyl-4- hydroxybenzoate            50     g ______________________________________

Procedure as describes in Example I.

Plastisol from S P.V.C., k-value 70/72, plasticizer content 50%. Per 100 kg of P.V.C. 2.7-3 kg of the stabilizing composition of the present Example is used corresponding with 200 kg of plastisol (P.V.C.: plasticizer=1:1). Lithium isostearate       300 g Stabilizer M2             300 g Polybutyl imine           300 g Benzoyl-2,3-dimethyl-alpha-naphthindole 100 g Pentaerythritol monomontanate triisostearate 300 g Pentaerythritol monoisostearate monoadipate 800 g Isostearic acid           150 g Triphenyl phosphite       300 g ______________________________________

Procedure as described in Example I. P.V.C. resin, k-value 67/68 100        parts by weight Omya BSH (calcium carbonate) 8          " Carbon black      0.6        " Calcium dialkyl-phenolate 2.76       " Stabilizer M1     0.30       " Polybutyl imine   0.10-0.40  " Trimethylol diisostearate 0.60       " Diphenyl isooctyl phosphite 0.30       " Benzoyl-2,3-dimethyl-alpha- naphthindole      0.05       " Epoxy soya bean oil 2.00       " Isostearic acid   0.50       " ______________________________________

The above components are mixed at ambient temperature until a dry powder is obtained. This powder is suitable for the extrusion of tubes. As mixing apparatus the Nautamixer with Rotor-Dispenser can be used. P.V.C. resin, k-value 67/71 100     parts by weight Omya BSH (chalk)   10      " Barium dialkyl-phenolate 2.75    " Titanium dioxyde   0.50    " Stabilizer M1      0.30    " Polybutyl imine    0.10    " Benzoyl-2,3-dimethyl-alpha- naphthindole       0.005   " Diphenyl isooctyl phosphite 0.60    " Epoxy soya bean oil 2.00    " Dibutyl phthalate  15.00   " Dioctyl phthalate  35.00   " Pentaerythritol tetraisostearate 0.40    " (Dipropylene glycol) adipate (polymer)          10.00   " Isostearic acid    0.30    " ______________________________________

The above components are heated at 100.degree. C., until a dry powdery agglomerate is obtained. This powdery agglomerate is suitable for injection molding of e.g. shoe soles and other flex. P.V.C. injection molding products as well as for the extrusion of garden-hose and flexible profiles. Emulsion-type P.V.C. resin, k-value 70/72                100     parts by weight Barium dialkyl-phenolate 2.75    " Stabilizer M1        0.30    " Diphenyl isooctyl phosphite 1.00    " Polybutyl imine      0.10    " 2,3-Dimethyl-alpha-naphthindole 0.005   " Epoxy soy bean oil   3.00    " Dibutyl phthalate    20.00   " Dioctyl adipatae     30.00   " Dioctyl phthalate    30.00   " (Dipropylene glycol) adipate (polymer)            20.00   " Pentaerythritol tetraisostearate 0.40    " Isostearic acid      0.08    " Silicone oil         0.02    " ______________________________________

The above components are mixed at ambient temperature in a Nautamixer, provided with a Rotor-Dispenser to obtain a homogeneous well flowing thick liquid, which, after standing for a few hours, becomes totally free of air. This liquid can be processed, amongst others, to obtain PVC-dips and PVC-pastes. After gelation the material is perfectly transparent and light resistant. By the addition of pigments every desired colour can be obtained, both transparent and non-transparent. P.V.C. resin, k-value 67/71 100     parts by weight Stabilizer M2      0.3     " Trinonyl phenyl phosphite 0.4     " Polybutyl imine    0.1     " Benzoyl-2,3-dimethyl-alpha- naphthindole       0.05    " Epoxy soy bean oil 3.0     " Glycerol monoleate 0.2     " Glycerol dioleate  0.2     " Diisobutyl adipate 10.0    " Dioctyl adipate    10.0    " Aceto-tri-n-butylcitrate 40.0    " Pentaerythritol tetraisostearate 1.0     " Oleic acid         0.3     " ______________________________________

The above components are heated at 100.degree./110.degree. C. until a dry agglomerate is obtained, which is suitable for calandering of flex. P.V.C. film for packaging of i.a. meat-products. P.V.C. resin, k-value 67/71 100     parts by weight Stabilizer M2      0.3     " Trinonyl phenyl phosphite 0.4     " Poly-2-methylbutyl imine 0.1     " Benzoyl-2,3-dimethyl-alpha- naphthindole       0.05    " Epoxy soy bean oil 3.0     " Lithium isostearate 1.2     " Glycerol monoisostearate 0.2     " Glycerol disostearate 0.2     " Isostearic acid    0.5     " Diisobutyl adipate 10.0    " Dioctyl adipate    10.0    " Aceto-tri-n-butylcitrate 40.0    " ______________________________________

The above components are heated at 100.degree./110.degree. C. until a dry agglomerate is obtained, which is suitable for calandering flex. P.V.C. glass-clear film. This film can be used for packaging foods. P.V.C. resin, k-value 67/71 100     parts by weight Lithium isostearate 1.2     " Stabilizer M3      0.3     " Diphenyl isooctyl phosphite 0.4     " Poly-2-methylbutyl imine 0.1     " Benzoyl-2-phenyl-3-methyl naphthindole       0.03    " Epoxy soy bean oil 3.0     " Pentaerythritol monoisostearate 0.2     " Diisooctyl adipate 20.0    " Dioctyl phthalate  30.0    " Poly-(dipropylene)-glycol adipate 10.0    " Isostearic acid    0.5     " ______________________________________

The above components are heated at 100.degree./110.degree. C. until a dry agglomerate is obtained. This agglomerate is suitable for calandering flex. P.V.C., glass-clear and light resistant film and can also be processed on injection molding apparatus to obtain highly transparent and light resistant products.

The stabilizing effect of the stabilizers prepared according to the Examples I-XII and the formulations according to the invention is compared with a Ba/Cd/Zn-stabilizer having metal contents of about 5.3% barium, 3.2% cadmium and 0.5% zinc, which has shown to be suitable for calander processing. To this end 100 g of S. P.V.C. (k-value 70), 50 g of dioctyl phthalate, 0.5 g of paraffin wax and 2.0 g of stabilizer is mixed in a high velocity mixing apparatus and the heat stability is tested by a milling test at 190.degree. C. Samples were taken at 5 minute intervals and the results are shown in the following table. __________________________________________________________________________ Stabilizer Rolled 5' 10' 15' 20' 25' 30' 35' 40' 45' 50' film Ba/Cd/Zn 5,6 9,6 11,7 14 15,9 15,2  31,1 Brown stabilizer According to 2,0 2,1 3,2 4,8 5,2 5,8 6,3 7,8 8,5 9,1 9,8 Example I, Rigid P.V.C. According to 2,0 2,0 2,8 3,2 4,0 4,2 4,8 5,3 6,2 7,8 8,4 Example II, Rigid P.V.C. According to 2,0 2,0 2,1 2,6 3,3 3,8 4,0 4,6 5,1 5,8 6,2 Example III, Rigid P.V.C. According to 2,2 2,2 2,4 2,6 3,1 3,5 3,8 4,1 4,8 5,2 5,8 Example IV, Flex. P.V.C. According to 2,2 2,2 2,3 2,3 2,6 3,0 3,2 3,8 4,0 4,9 5,8 Example V, Flex. P.V.C. According to 2,0 2,0 2,2 2,8 3,2 3,8 4,6 5,3 6,8 7,4 8,9 Example VI, Rigid P.V.C. According to Black Bl. Bl. Bl. Bl. Bl. Bl. Bl. Bl. Bl. Bl. Example VII, Rigid P.V.C. black According to White Wh. Wh. Wh. Wh. Wh. Wh. Wh. Wh. Wh. Yellow Example VIII, Flex. P.V.C. white According to 2,2 2,2 2,2 2,2 2,3 2,6 3,0 3,8 4,6 5,8 7,2 Example IX, Flex. P.V.C. According to 2,2 2,3 2,6 3,0 3,6 4,2 5,8 6,3 6,8 7,6 8,2 Example X, Flex. P.V.C. According to 2,2 2,2 2,4 2,6 2,8 3,2 3,8 4,6 5,3 6,1 6,9 Example XI, Flex. P.V.C. According to 2,2 2,2 2,2 2,3 2,6 2,8 3,2 3,8 4,6 5,2 5,8 Example XII, Flex. P.V.C. __________________________________________________________________________

The table shows the superiority of the stabilizer and the formulation of the present invention, which is still emphasized by the remarkable stabilizing effect with respect to rigid and flexible P.V.C.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

## Claims

1. Liquid stabilizing composition for use in chlorine containing thermoplastic polymers, comprising aluminum chloride or mixtures of the zinc chloride and/or aluminum chloride with magnesium chloride, calcium chloride, lithium chloride and barium chloride; ethoxy groups; acids and/or aliphatic saturated and branched monocarboxylic acids;

2. Composition according to claim 1, characterized in that the said aliphatic monocarboxylic acid contains from 6 to 18 carbon atoms.

3. Composition according to claim 1, characterized in that the said unsaturated aliphatic monocarboxylic acid contains from 16 to 18 carbon atoms.

4. Composition according to claim 1, characterized in that the said aliphatic monocarboxylic acid is branched on the alpha-position.

5. Composition according to claim 1, characterized in that the said aliphatic monocarboxylic acid is saturated and contains from 8 to 13 carbon atoms.

6. Composition according to claim 1, characterized in that it comprises polybutyl imine as component e.

7. Composition according to claim 1, characterized in that it comprises poly-2-methylbutyl imine as component e.

8. Composition according to claim 1, characterized in that it comprises 2,3-dimethyl-alpha- or -beta-naphthindole as component f.

9. Composition according to claim 1, characterized in that it comprises 2-phenyl-3-methyl-alpha- or -beta-naphthindole as component f.

10. Composition according to claim 1, characterized in that it comprises benzoyl-2,3-dimethyl-alpha- or -beta-naphthindole as component f.

11. Composition according to claim 1, characterized in that it comprises benzoyl-2-phenyl-3-methyl-alpha-or -beta-naphthindole as component f.

12. Composition according to claim 1, characterized in that it comprises an ethoxylated tert.dodecyl mercaptan as component b.

13. Composition according to claim 1, characterized in that it comprises an alkyl aryl phosphite as component d.

14. Composition according to claim 13, characterized in that it comprises a dialkyl phenyl phosphite.

15. Composition according to claim 13, characterized in that the alkyl group contains from 8 to 14 carbon atoms.

16. Composition according to claim 15, characterized in that it comprises ditetradecyl phenyl phosphite, didecyl phenyl phosphite, dimyristyl phenyl phosphite, myristyl diphenyl phosphite or (dinonylphenyl) isotridecyl phosphite.

17. Composition according to any one of the preceding claims, comprising furthermore an antioxidant selected from the group consisting of sterically hindered alkyl phenols, such as 2,6-di-tert.butyl-4-methylphenol and 4-hydroxymethyl-2,6-di-tert.butylphenol.

18. Stabilized compositions comprising a thermoplastic polyvinyl halide substrate selected from one member of the group consisting of polyvinyl chloride and polyvinylidene chloride and 0.5-8% by weight, based upon the total composition, of the stabilizing composition of any one of the preceding claims.

19. Composition according to claim 18 characterized in that it comprises a polymer of, or based upon, vinyl chloride.

20. Composition according to claim 19, comprising furthermore a plasticizer.

21. Composition according to claim 19, characterized in that the polymer is an S- or an M-polyvinyl chloride.