WO1997030112A1

WO1997030112A1 - Stabilisation of polyolefin-recyclates

Info

Publication number: WO1997030112A1
Application number: PCT/EP1997/000497
Authority: WO
Inventors: Rudolf Pfaendner; Heinz Herbst; Kurt Hoffmann
Original assignee: Ciba Specialty Chemicals Holding Inc.
Priority date: 1996-02-15
Filing date: 1997-02-04
Publication date: 1997-08-21
Also published as: EP0880557A1; JP2000506185A; AU1600597A; CA2243697A1; TW364911B

Abstract

Polyolefin recyclates can, by adding at least one secondary aromatic amine and at least one polyfunctional epoxide, be stabilized against oxidative, thermal or light-induced degradation.

Description

Stabilisation of polvolefin-recvclates

The invention relates to a process for stabilizing polyolefin recyclates, to a stabilizer mixture, and to the recycled polyolefins obtainable by the process.

The stabilization of recycled plastics for processing and re-use gives rise to specific problems as a result of prior damage and associated structural alteration of the polymer chains, and as a result of the impurities often present. The resulting differences from virgin plastics have necessitated the development of stabilizers for recyclates. From WO-A- 94/07946, WO-A-94/07950, WO-A-94/07951 and WO-A-94/29377 it is known that combinations of phenolic antioxidants, phosphites and epoxides are suitable for stabilizing previously damaged thermoplastics. With these systems, however, it is necessary to use at least three components.

So that the concentrations in which they are used can be kept low, epoxides of high epoxide content are expedient. However, commercially available epoxides of high epoxide content are often liquid or low-melting products, whereas the abovementioned phosphites and phenolic antioxidants are solids. The addition of both liquid and solid products at the same time in the course of processing may, however, cause problems, or may necessitate extensive technical equipment. Yet as a result of the low use concentrations of liquid epoxides and their overall low price, there are economic advantages.

The object of the present invention was therefore to provide a stabilization system which has very good stabilizing properties and consists as far as possible of liquid, homogeneously miscible components. Furthermore, the stabilizer system should be economically acceptable for use in recyclates, i.e. it should either be effective in low concentrations or consist of inexpensive components.

It has now surprisingly been found that a mixture comprising a secondary aromatic amine and a polyfunctional epoxide is particularly suitable for stabilizing polyolefin recyclates in accordance with the requirements set out above. The present invention therefore provides a process for stabilizing a polyolefin recyclate against oxidative, thermal or light-induced degradation, which comprises adding thereto at least one secondary aromatic amine and at least one polyfunctional epoxide.

The invention is particularly important in connection with polyolefin recyclates as are obtained from production waste, collections of recyclable material from households, in retail outlets or through obligatory takeback schemes, for example in the automotive industry, such as for old battery cases, or in the electrical sector. Examples of the products involved are films, such as agricultural films, pouches, bottles and other containers. These polyolefin recyclates may have suffered a wide variety of oxidative, thermal and/or light-induced damage. Furthermore, these recyclates may also, in minor amounts, include admixed plastics of different structure, for example styrene polymers (IPS, EPS, ABS, ASA), polyesters (PET) or polyamides, and also customary impurities, for example paint residues, traces of metal, fuel residues, ethylene glycol, isopropanol or else traces of water.

Polyolefin recyclates are derived from the following pure polyolefins:

1. Polymers of mono- and diolefins, for example polypropylene, polyisobutylene, polybut-1- ene, poly-4-methylpent-1 -ene, polyisoprene or polybutadiene, and also polymers of cycloolefins, for example of cyclopentene or norbornene; furthermore polyethylene (which can be crosslinked), for example high-density polyethylene (HDPE), high-density polyethylene of high molar mass (HDPE-HMW), high-density polyethylene of ultra high molar mass (HDPE-UHMW), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE) and branched low-density polyethylene (VLDPE).

Polyolefins, i.e. polymers of monoolefins exemplified in the preceding paragraph, especially polyethylene and polypropylene, can be prepared by different, and especially by the following, methods:

a) free-radically (normally under high pressure and at a high temperature)

b) by means of a catalyst, the catalyst normally containing one or more metals of group IVb, Vb, VIb or Vlll. These metals usually have one or more ligands, such as oxides, halides, alcoholates, esters, ethers, amines, alkyls, alkenyls and/or aryls that may be either π- or σ-coordinated. These metal complexes may be in free form or fixed on substrates, for example on activated magnesium chloride, titanium (III) chloride alumina or silica. These catalysts may be soluble or insoluble in the polymerization medium. The catalysts can be active as such in the polymerization or further activators may be used, for example metal alkyls, metal hydrides, metal alkyl halides, metal alkyl oxides or metal alkyloxanes. The metals being elements of groups la, lla and/or Ilia. The activators may be modified, for example, with further ester, ether, amine or silyl ether groups. These catalysts are usually termed Phillips, Standard Oil Indiana, Ziegler (-Natta), TNZ (DuPont), metallocene or single site catalysts (SSC).

2. Mixtures of the polymers mentioned under 1 ), for example mixtures of polypropylene with polyisobutylene, polypropylene and polyethylene (e.g. PP/HDPE, PP/LDPE) and mixtures of different types of polyethylene (e.g. LDPE/HDPE).

3. Copolymers of monoolefins and diolefins with each other or with other vinyl monomers, for example ethylene-propylene copolymers, linear low-density polyethylene (LDPE) and mixtures thereof with low-density polyethylene (LDPE), propylene-but-1 -ene copolymers, propylene-isobutylene copolymers, ethylene-but-1 -ene copolymers, ethylene-hexene copolymers, ethylene-methylpentene copolymers, ethylene-heptene copolymers, ethylene- octene copolymers, propylene-butadiene copolymers, isobutylene-isoprene copolymers, ethylene-alkyl acrylate copolymers, ethylene-alkyl methacrylate copolymers, ethylene-vinyl acetate copolymers and copolymers thereof with carbon monoxide, or ethylene-acrylic acid copolymers and salts thereof (ionomers), and also terpolymers of ethylene with propylene and a diene, such as hexadiene, dicyclopentadiene or ethylidenenorbornene; furthermore, mixturers of such copolymers with each other and with polymers mentioned under 1 ), for example polypropylene/ethylene-propylene copolymers, LDPE/ethylene-vinyl acetate copolymers, LDPE/ethylene-acrylic acid copolymers, LLDPE/ethylene-vinyl acetate copolymers, LLDPE/ethylene-acrylic acid copolymers and alternating or random polyalkylene-carbon monoxide copolymers and mixtures thereof with other polymers, for example polyamides. The polyolefin recyclate is preferably a copolymer recyclate of mono- and diolefins, especially a polypropylene copolymer recyclate from battery cases or a polyethylene copolymer recyclate.

Polyethylene recyclates or polypropylene recyclates are also particularly preferred.

Preference is given to the novel process for stabilizing a polyolefin recyclate against oxidative, thermal and/or light-induced degradation wherein both the secondary aromatic amine and the polyfunctional epoxide are in liquid form.

Secondary aromatic amines are, for the purposes of this invention, preferably compounds of the formula I

in which

Ri is hydrogen or Cι-C₂₅alkyl,

R₂ is hydrogen, Cι-C₂ alkyl or benzyl,

R₃ is hydrogen, CrC₂₅alkyl, C₃-Cι₂cycloalkyl, benzyl, α-methylbenzyl or α,cc-dimethylbenzyl;

or R₂ and R₃ together form a divalent group

R₄ is hydrogen, Cι-C_2Salkyl or benzyl,

R₅ is hydrogen or Cι-C₂₅alkyl,

Rβ is hydrogen, d-C₂₅alkyl or benzyl,

R₇ is hydrogen, d-C^alkyl, C₅-Cι₂cycloalkyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl or — N

R₈ is hydrogen, Cι-C₂₅alkyl or benzyl, R₉ is hydrogen or Cι-C₂₅alkyl, and

R₁₀ is C₅-C₁₂cycloalkyl,

Alkyl of up to 25 carbon atoms is a branched or unbranched radical such as, for example, methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1 ,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1 ,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1 ,1,3-trime- thylhexyl, 1 ,1 ,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octa¬ decyl, eicosyl or docosyl. One of the preferred definitions of Ri, R₂, R₄, R₅, Rβ and R₈ is for example C C₁₈alkyl, especially CrCι₂alkyl, for instance Cι-C_βalkyl. A preferred definition of R₃ and R₇ is for example Cι-Cι₈alkyl, especially CrCι₂alkyl, for instance C -C₁₂alkyl. A parti¬ cularly preferred definition of R₃ and R₇ is C₄-Cιoalkyl, especially C₄-C_βalkyl, for instance tert-butyl or tert-octyl.

C₅-Cι₂cycloalkyl is, for example, cyclopentyl, cyclohexyl, cycloheptyi, cyclooctyl, cyclodecyl or cyclododecyl. A preferred definition of R₃, R₇ and Rio is for example Cs-Cβcycloalkyl, es¬ pecially C₅-C₇cycloalkyl, for instance cyclohexyl.

Particularly preferred compounds of the formula I are those in which

Ri and R₂ independently of one another are hydrogen or CrCι_βalkyl,

R₃ is hydrogen, Cι-Cι_βalkyl, Cs-C₈cycloalkyl, benzyl, α-methylbenzyl or α,α-dimethylbenzyl;

or R₂ and R₃ together form a divalent group

R_4l R₅ and R₆ independently of one another are hydrogen or Cι-C ₈alkyl,

R is hydrogen, Ci-Ciβalkyl, C₅-Cβcycloalkyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl or — N

R₈ and R₉ independently of one another are hydrogen or C -Cι₈alkyl, and

R₁₀ is C₅-C₈cycloalkyl, T| — ] — R₉ or

Of particular interest are the secondary aromatic amines of the formula I in which R_u R₄, R₅, R₆ and R₈ are hydrogen.

Of specific interest are the compounds of the formula I in which

R and R₂ are hydrogen,

R₃ is hydrogen, C₄-Cι₂alkyl, cyclohexyl, benzyl, α-methylbenzyl or α,α-dimethylbenzyl; or R₂

and R₃ together form a divalent group

R , R₅ and R₆ are hydrogen,

R₇ is hydrogen,

cyclohexyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl or

H /

- ^■ ^R10

R₈ and R₉ are hydrogen, and

Rio is cyclohexyl, phenyl or β-naphthyl.

Very particular preference is given to the secondary aromatic amines of the formulae la, lb, lc, Id, Ie and If.

As secondary aromatic amines, specific preference is given to the compounds of the formulae Ie [4,4'-di-tert-octyldiphenylamine, Irganox® 5057 (Ciba-Geigy)] and If [N,N'- diphenyl-p-phenylenediamine] and to the compounds of the formula I in which Ri, R2. R4, Rs. Rβ and R_β are hydrogen, R₃ is hydrogen or C₈alkyl, H /

R₇ is C₈alkyl or — N and

^R10

R₁₀ is phenyl.

The compounds of the formula I are known; some of them are available commercially and some can be prepared as described in R. Gachter and H. Mϋller, Hanser Verlag, "Plastics Additives Handbook, 3rd Ed.", page 44 to 45 (1990), in analogy to the literature references cited therein.

For the purposes of this invention, polyfunctional epoxides can have an aliphatic, aromatic, cycloaliphatic, araliphatic or heterocyclic structure; they include epoxide groups as side groups, or these groups form part of an alicyclic or heterocyclic ring system. The epoxide groups are preferably attached as glycidyl groups to the remainder of the molecule by way of ether or ester linkages, or the compounds involved are N-glycidyl derivatives of hetero¬ cyclic amines, amides or imides. Epoxides of these types are generally known and commer¬ cially available.

The polyfunctional epoxides comprise two epoxide radicals, for example those of the formu¬ la II

which are attached directly to carbon, oxygen, nitrogen or sulfur atoms, in which R and Rι₃ are both hydrogen, Rι₂ is hydrogen or methyl and n is 0; or in which Ru and Rι₃ together are -CH₂CH₂- or -CH₂CH₂CH₂-, Rι₂ is then hydrogen, and n is 0 or 1.

Examples of epoxides are: 1. Diglycidyl and di(β-methylglycidyl) esters obtainable by reacting a compound with two carboxyl groups in the molecule and epichlorohydrin and or glycerol dichlorohydrin and/or β-methylepichlorohydrin. The reaction is expediently carried out in the presence of bases.

As compounds of two carboxyl groups in the molecule, aliphatic dicarboxylic acids can be used. Examples of these dicarboxylic acids are glutaric acid, adipic acid, pimelic acid, sube¬ ric acid, azelaic acid, sebacic acid or dimerized or trimerized linoleic acid.

It is however also possible to employ cycloaliphatic dicarboxylic acids for example tetrahy- drophthalic acid, 4-methyltetrahydrophthalic acid, hexahydrophthalic acid or 4-methylhexa- hydrophthalic acid.

Furthermore, aromatic dicarboxylic acids, for example phthalic acid or isophthalic acid, can be used.

2. Diglycidyl, or di(β-methyiglycidyl) ethers obtainable by reacting a compound with two free alcoholic hydroxyl groups and/or phenolic hydroxyl groups and a suitable substituted epi¬ chlorohydrin under alkaline conditions, or in the presence of an acidic catalyst with subse¬ quent alkali treatment.

Ethers of this type are derived, for example, from acyclic alcohols, such as ethylene glycol, diethylene glycol and higher poly(oxyethylene) glycols, propane-1 ,2-diol,or polyoxypropy¬ lene) glycols, propane- 1 ,3-diol, butane-1 ,4-diol, poiy(oxytetramethylene) glycols, pentane- 1 ,5-diol, hexane-1 ,6-diol, sorbitol, and from polyepichlorohydrins.

However, they are also derived, for example, from cycloaliphatic alcohols such as 1,3- or 1 ,4-dihydroxycyclohexane, bis(4-hydroxycyclohexyl)methane, 2,2-bis(4-hydroxycyclo-hexyl)- propane or 1 ,1-bis(hydroxymethyl)cyclohex-3-ene, or they possess aromatic nuclei, such as N,N-bis(2-hydroxyethyl)aniline or p,p'-bis(2-hydroxyethylamino)diphenylmethane.

The epoxides can also be derived from mononuclear phenols, for example from resorcinol, pyrocatechol or hydroquinone; or they are based on poiynuclear phenols such as, for example, on 4,4'-dihydroxybiphenyl, bis(4-hydroxphenyl)methane, 2,2-bis(4-hydroxy-phe- nyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3,5-dibromo-4-hydroxy- phenyl)propane, 4,4'-dihydroxybiphenyl sulfone, 9,9'-bis(4-hydroxyphenyl)fluorene, or on a condensate of phenols with formaldehyde obtained under acidic conditions, such as phenol novolaks.

3. Di(N-glycidyl) compounds are obtainable, for example, by dehydrochlorination of the reaction products of epichlorohydrin with amines containing two amino hydrogen atoms. Examples of these amines are aniline, toluidine, n-butylamine, bis(4-aminophenyl)methane, m-xylylenediamine or bis(4-methylaminophenyl)methane.

Also included among the di(N-glycidyl) compounds, however, are N,N'-diglycidyl derivatives of cycloalkyleneureas, such as ethyleneurea or 1 ,3-propyleneurea, and N,N'-diglycidyl deri¬ vatives of hydantoins such as of 5,5-dimethylhydantoin.

4. Di(S-glycidyl) compounds, such as di-S-glycidyl derivatives derived from dithiols, for example ethane-1 ,2-dithiol or bis(4-mercaptomethylphenyl) ether.

5. Epoxides with a radical of the formula II in which Rn and Rι₃ together are -CH₂CH₂- and n is 0 are, for example, bis(2,3-epoxycyclopentyl) ether, 2,3-epoxycyclopentyl glycidyl ether or 1 ,2-bis(2,3-epoxycyclopentyloxy)ethane; examples of epoxides with a radical of the formula II in which R and R_i3 together are -CH₂CH₂- and n is 1 are (3',4'-epoxy-6'-methylcyclohe- xyl)methyl 3,4-epoxy-6-methylcyclohexanecarboxylate and 3,4-epoxycyclohexylmethyl 3,4- epoxycyclohexanecarboxylate.

Owing for example to the preparation process, the abovementioned difunctional epoxides may include small amounts of mono- or trifunctional fractions.

Predominantly, use is made of diglycidyl compounds having aromatic structures.

If desired, it is also possible to employ a mixture of epoxides of different structure.

Preference is given to the novel process for stabilizing polyolefin recyclates against oxida¬ tive, thermal and/or light-induced degradation wherein the polyfunctional epoxide is a di¬ functional epoxide. Examples of suitable difunctional epoxides are:

a) liquid bisphenol A diglycidyl ethers, such as Araldit®GY 240, Araldit®GY 250, Araldit®GY 260, Araldit®GY 266, Araldit®GY 2600 or Araldit®MY 790;

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

c) liquid bisphenol F diglycidyl ethers, such as Araldit®GY 281 , Araldit®GY 282, Araldit®PY 302, or Araldit®PY 306;

d) liquid glycidyl ethers of alcohols, such as Shell®Glycidyiether 162, Araldit®DY 0390 or Araldit®DY 0391;

e) liquid glycidyl esters of carboxylic acids, such as Shell®Cardura E terephthalic ester, trimellitic ester, AralditΦPY 284 or mixtures of aromatic glycidyl esters, for example Araldit®PT 910;

f) liquid cycloaliphatic epoxy resins such as Araldit®CY 179.

On the other hand, tri- and polyfunctional epoxides can be employed supplementarily, in order, if desired, to obtain branching sites. Examples thereof which are suitable are:

a) solid polyglycidyl ethers of tetraphenylethane, such as CG Epoxy Resin®0163;

b) solid and liquid polyglycidyl ethers of phenol-formaldehyde novolak such as EPN 1138, EPN 1139, GY 1180, PY 307; c) solid and liquid polyglycidyl ethers of o-cresole-formaldehyde novolak, such as ECN 1235, ECN 1273, ECN 1280, ECN 1299;

d) solid heterocyclic epoxy resins (triglycidyl isocyanurate) such as Araldit®PT 810;

e) liquid N,N,O-triglycidyl ethers of p-aminophenol, such as Araldit®MY 0510;

f) tetraglycidyl-4-4'-methylenebenzamine or N.N.N'.N'-tetraglycidyldiaminophenylmethane, such as Araldit®MY 720, Araldit®MY 721.

Particularly preferred difunctional epoxides are liquid or low-melting diglycidyl ethers based on bisphenols, for example on 2,2-bis-(4-hydroxyphenyl)propane (bisphenol A) or mixtures of bis(ortho/para-hydroxyphenyl)methane (bisphenol F).

Very particularly preferred epoxides are bisphenol A diglycidyl ethers, for example: Araldit®GT 6071 or Araldit®GY 260; bisphenol F diglycidyl ethers, for example Araldit® PY 306; liquid cycloaliphatic epoxy resins, for example Araldit®CY 179; or phenol novolak epoxy resins, e.g. Araldit®PY EPN 1139.

The process can be carried out in any vessels which can be heated and are fitted with a stirring device. These may, for example, be closed apparatus from which atmospheric oxy¬ gen is excluded, working for example under an inert gas atmosphere such as nitrogen. The process is preferably conducted in an extruder.

The polyolefin recyclate to be heated and the mixture comprising a secondary aromatic amine and a difunctional epoxide are normally charged to the apparatus at the beginning of heating; however, subsequent metered addition of the novel mixture to the polyolefin re¬ cyclate is a further option, it being possible to add the mixture as such or else to add the individual components in any desired sequence.

For addition, the secondary aromatic amine and the polyfunctional epoxide can, indepen¬ dently of one another, be present in the form of a liquid, powder, granules or in compacted form, or else on a carrier material such as silica gel, or together with a polymer powder or wax, for example a polyethylene wax. In the present novel process, liquid addition is pre¬ ferred.

For each 100 parts of polyolefin recyclate, it is preferred to employ from 0.01 to 5 parts of a secondary aromatic amine and from 0.01 to 10 parts of a polyfunctional epoxide. In this context, particular preference is given to the use of from 0.05 to 5 parts, especially from 0.05 to 2 parts, of a secondary aromatic amine, and from 0.05 to 5 parts, especially from 0.05 to 2 parts, of a polyfunctional epoxide.

The novel process has the advantage that the polyolefin recyclate is stabilized in short reac¬ tion times, and the additives, for example the secondary aromatic amine and the polyfunc¬ tional epoxide, can be added in liquid form. The combination of secondary aromatic amines with polyfunctional epoxides leads synergistically to the stabilization of polyolefin recyclates.

The present invention also provides a mixture comprising a) a secondary aromatic amine and b) a polyfunctional epoxide, the weight ratio of the components a): b) being from 10:1 to 1:10, in particular from 5:1 to 1:5, for example from 2:1 to 1:2. Special preference is given to a weight ratio of components a): b) of from 1.5:1 to 1 :1.5, in particular from 1.1:1 to 1:1.1 , for example 1 :1.

The preferences regarding a) and b) correspond to those for the novel process.

In addition to the mixture of a secondary aromatic amine and a polyfunctional epoxide, addi¬ tional stabilizers and additives can be added to the polyolefin recyclate. The following are examples of such additives:

1. Antioxidants

1.1. Alk lated monophenols. for example 2,6-di-tβrt-butyl-4-methylphenol, 2-tert-butyl-4,6-di- methylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-bu- tyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2-(α-methylcyclohexyl)-4,6-dimethyl- phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-di-tert-butyl-4- methoxymethylphenol, nonylphenols which are linear or branched in the side chains, for example, 2,6-di-nonyl-4-methylphenoI, 2,4-dimethyl-6-(1 '-methylundec-1 '-yl)phenol, 2,4-di- methyl-6-(1 '-methylheptadec-1 '-yl)phenol, 2,4-dimethyl-6-(1 '-methyitridec-1 '-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols. for example 2,4-dioctylthiomethyl-6-tert-butylphenol, 2,4-dioc- tylthiomethyl-6-methylphenol, 2,4-dioctylthiomethyl-6-ethylphenol, 2,6-di-dodecylthiomethyl- 4-nonylphenol.

1.3. Hvdroquinones and alkylated hvdroαuinones. for example 2,6-di-tert-butyl-4-methoxy- phenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4-octade- cyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert- butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis-(3,5-di-tert-butyl-4- hydroxyphenyl) adipate.

1.4. Tocopherols. for example α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and mixtures thereof (Vitamin E).

1.5. Hvdroxylated thiodiphenyl ethers, for example 2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylphenol), 4,4'-thiobis(6-tert-butyl- 2-methylphenol), 4,4'-thiobis-(3,6-di-sec-amylphenol), 4,4'-bis(2,6-dimethyl-4-hydroxyphe- nyl)disulfide.

1.6. Alkylidenebisphenols. for example 2,2'-methylenebis(6-tert-butyl-4-methylphenol), 2,2'- methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis[4-methyl-6-(α-methylcyclohexyl)- phenol], 2,2'-methylenebis(4-methyl-6-cyclohexylphenol), 2,2'-methylenebis(6-nonyl-4-me- thylphenol), 2,2^,-methylenebis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butyl- phenol), 2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis[6-(a-methylben- zyl)-4-nonylphenol], 2,2'-methylenebis[6-(a,a-dimethylbenzyl)-4-nonylphenol], 4,4'-methy- lenebis(2,6-di-tert-butylphenol), 4,4'-methylenebis(6-tert-butyl-2-methylphenol), 1,1-bis(5- tert-butyl-4-hydroxy-2-methylphenyl)butane, 2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)- 4-methylphenol, 1 ,1 ,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane, 1 ,1-bis(5-tert-butyl- 4-hydroxy-2-methyl-phenyl)-3-n-dodecylmercaptobutane, ethylene glycol bis[3,3-bis(3'-tert- butyl-4'-hydroxyphenyl)butyrate], bis(3-tert-butyl-4-hydroxy-5-methyl-phenyl)dicyclopentadi- ene, bis[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl]terephtha- late, 1 ,1-bis-(3,5-dimethyl-2-hydroxyphenyl)butane, 2,2-bis-(3,5-di-tert-butyl-4-hydroxyphe- nyl)propane, 2,2-bis-(5-tert-butyl-4-hydroxy2-methylphenyl)-4-n-dodecylmercaptobutane, 1 ,1 ,5,5-tetra-(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-. N- and S-benzyl compounds, for example 3,5,3\5 etra-tert-butyl-4,4'-dihydroxydi- benzyl ether, octadecyl-4-hydroxy-3,5-dimethylbenzylmercaptoacetate, tridecyl-4-hydroxy- 3,5-di-tert-butylbenzylmercaptoacetate, tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine, bis(4- tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithioterephthalate, bis(3,5-di-tert-butyl-4-hydroxy- benzyl)sulfide, isooctyl-3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates. for example dioctadecyl-2,2-bis-(3,5-di-tert-butyl-2-hy- droxybenzyl)-malonate, di-octadecyl-2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)-malonate, di- dodecylmercaptoethyl-2,2-bis-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, bis[4-(1 ,1 ,3,3-te- tramethylbutyl)phenyl]-2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Aromatic hvdroxybenzyl com^pounds, for example 1 ,3,5-tris-(3,5-di-tert-butyl-4-hydroxy- benzyl)-2,4,6-trimethylbenzene, 1 ,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetrame- thylbenzene, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine Compounds, for example 2,4-bis(octylmercapto)-6-(3,5-di-tert-butyl-4-hy- droxyanilino)-1 ,3,5-triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1 ,3,5- triazine, 2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1 ,3,5-triazine, 2,4,6- tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1 ,2,3-triazine, 1 ,3,5-tris-(3,5-di-tert-butyl-4-hydroxy- benzyl)isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate, 2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine, 1 ,3,5-tris(3,5-di-tert-butyl-4- hydroxyphenylpropionyl)-hexahydro-1 ,3,5-triazine, 1 ,3,5-tris(3,5-dicyclohexyl-4-hydroxyben- zyl)isocyanurate.

1.11. Benzylphosphonates. for example dimethyl-2,5-di-tert-butyl-4-hydroxybenzylphospho- nate, diethyl-3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hy- droxybenzylphosphonate, dioctadecyl-5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt of the monoethyl ester of 3,5-di-tert-butyl-4-hydroxybenzylphosphonic acid. 1.12. Acylaminophenols. for example 4-hydroxylauranilide, 4-hydroxystearaπilide, octyl N- (3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3.5-di-tert-butyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1 ,6-hexanediol, 1,9- nonanediol, ethylene glycol, 1 ,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethy¬ lene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hy- droxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylol¬ propane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.14. Esters of ^β-⁽5-tert-butyl-4-hvdroxy-3-methylphenvt propionic acid with mono- or poly¬ hydric alcohols, e.g. with methanol, ethanol, n-octanol, i-octanol, octadecanol, 1,6-hexane- diol, 1,9-nonanediol, ethylene glycol, 1 ,2-propanediol, neopentyl glycol, thiodiethylene gly¬ col, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxamide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.15. Esters of β-(3.5-dicvclohexyl-4-hydroxyphenyl)propionic acid with mono- or polyhydric alcohols, e.g. with methanol, ethanol, octanol, octadecanol, 1 ,6-hexanediol, 1 ,9-nonanediol, ethylene glycol, 1 ,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox- amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy- droxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.16. Esters of 3.5-di-tert-butyl-4-hvdroxyphenyl acetic acid with mono- or polyhydric alco¬ hols, e.g. with methanol, ethanol, octanol, octadecanol, 1 ,6-hexanediol, 1 ,9-nonanediol, ethylene glycol, 1 ,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)ox- amide, 3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol, trimethylolpropane, 4-hy- droxymethyl-1-phospha-2,6,7-trioxabicyclo[2.2.2]octane.

1.17. Amides of β-(3.5-di-tert-butyl-4-hvdroxyphenvnpropionic acid e.g. N,N'-bis(3,5-di-tert- butyl-4-hydroxyphenylpropionyl)hexamethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxy- phenylpropionyljtrimethylenediamide, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)- hydrazide, N,N'-bis[2-(3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyloxy)ethyl]oxamide (Naugard^βXL-1 supplied by Uniroyal).

1.18. Ascorbic acid (vitamin C)

1.19. Aminic antioxidants. for example N.N'-di-isopropyl-p-phenylenediamine, N,N'-di-sec- butyl-p-phenylenediamine, N,N'-bis(1 ,4-dimethylpentyl)-p-phenylenediamine, N,N'-bis(1 - ethyl-3-methylpentyl)-p-phenylenediamine, N,N'-bis(1-methylheptyl)-p-phenylenediamine, N.N'-dicyclohexyl-p-phenylenediamine, N.N'-diphenyl-p-phenylenediamine, N,N'-bis(2-naph- thyl)-p-phenylenediamine, N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1 ,3-dimethylbutyl)- N'-phenyl-p-phenylenediamine, N-(1 -methylheptyl)-N'-phenyl-p-phenylenediamine, N-cyclo- hexyl-N'-phenyl-p-phenlenediamine, 4-(p-toluenesulfamoyl)diphenylamine, N,N'-dimethyl- N.N'-di-sec-butyl-p-phenylenediamine, diphenylamine, N-allyldiphenylamine, 4-isopropoxy- diphenylamine, N-phenyl-1-naphthylamine, N-(4-tert-octylphenyl)-1-naphthylamine, N-phe- nyl-2-naphthylamine, octylated diphenylamine, for example p,p'-di-tert-octyldiphenylamine, 4-n-butylaminophenol, 4-butyryiaminophenol, 4-nonanoylaminophenol, 4-dodecanoylamino- phenol, 4-octadecanoylaminophenol, bis(4-methoxyphenyl)amine, 2,6-di-tert-butyl-4-dime- thylamino ethylphenol, 2,4'-diaminodiphenylmethane, 4,4^,-diaminodiphenylmethane, N.N.N'.N'-tetramethyW^'-diaminodiphenylmethane, 1,2-bis[(2-methylphenyl)amino]ethane, 1 ,2-bis(phenylamino)propane, (o-tolyl)biguanide, bis[4-(1',3'-dimethylbutyl)phenyl]amine, tert-octylated N-phenyl-1-naphthylamine, a mixture of mono- and dialkylated tert-butyl/tert- octyldiphenylamines, a mixture of mono- and dialkylated nonyldiphenylamines, a mixture of mono- and dialkylated dodecyldiphenylamines, a mixture of mono- and dialkylated isopro- pyl/isohexyldiphenylamines, a mixture of mono- und dialkylated tert-butyldiphenylamines, 2,3-dihydro-3,3-dimethyl-4H-1 ,4-benzothiazine, phenothiazine, a mixture of mono- und dial¬ kylated tert-butyl/tert-octylphenothiazines, a mixture of mono- und dialkylated tert-octyl-phe- nothiazines, N-allylphenothiazin, N,N,N',N'-tetraphenyl-1 ,4-diaminobut-2-ene, N,N-bis- (2,2,6,6-tetramethyl-piperid-4-yl-hexamethylenediamine, bis(2,2,6,6-tetramethylpiperid-4-yl)- sebacate, 2,2,6,6-tetramethylpiperidin-4-one, 2,2,6,6-tetramethylpiperidin-4-ol.

2. UV absorbers and light stabilisers 2.1. 2-{2'-Hvdroxy^phenyl)benzotriazoles. for example 2-(2'-hydroxy-5'-methylphenyl)-benzo- triazole, 2-(3',5^,-di-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(5'-tert-butyl-2'-hydroxyphe- nyl)benzotriazole, 2-(2'-hydroxy-5'-(1 ,1 ,3,3-tetramethylbutyl)phenyl)benzotriazole, 2-(3',5'-di- tert-butyl-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl- 2'-hydroxy-5'-methylphe- nyl)-5-chloro-benzotriazole, 2-(3^,-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2- (2'-hydroxy-4'-octyloxyphenyl)benzotriazole, 2-(3^,,5'-di-tert-amyl-2'-hydroxyphenyl)benzotri- azole, 2-(3^,,5'-bis-(α,α-dimethylbenzyl)-2^,-hydroxyphenyl)benzotriazole, 2-(3'-tert-butyl-2'-hy- droxy-5'-(2-octyloxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-5'-[2-(2- θthylhexyloxy)-carbonylethyl]-2'-hydroxyphenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hy- droxy-5^,-(2-methoxycarbonylethyl)phenyl)-5-chloro-benzotriazole, 2-(3'-tert-butyl-2'-hydroxy- 5'-(2-methoxycarbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxy- carbonylethyl)phenyl)benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-ethylhexyloxy)carbonylethyl]-2'- hydroxyphenyl)benzotriazole, 2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(3'- tert-butyl-2'-hydroxy-5'-(2-isooctyloxycarbonylethyl)phenylbenzotriazole, 2,2'-methylene-bis- [4-(1,1,3,3-tetramethylbutyl)-6-benzotriazole-2-ylphenol]; the transesterification product of 2- [3'-tert-butyl-5'-(2-methoxycarbonylethyl)-2^,-hydroxyphenyl]-2H-benzotriazole with polyethy¬

lene glycol 300; [R-CH₂CH₂— COO-CH₂CH₂-3- where R = 3'-tert-butyl-4'-hydroxy-5'-2H-

benzotriazol-2-ylphenyl, 2-[2'-hydroxy-3'-(α,α-dimethylbenzyl)-5'-(1 ,1 ,3,3-tetramethylbutyl)- phenyl]benzotriazole; 2-[2'-hydroxy-3'-(1 ,1 ,3,3-tetramethylbutyl)-5'-(α,α-dimethylbenzyl)- phenyl]benzotriazole.

2.2.2-Hvdroxybenzophenones. for example the 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyl- oxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives.

2.3. Esters of substituted and unsubstituted benzoic acids, as for example 4-tertbutyl-phenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylben- zoyl) resorcinol, benzoyi resorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzo- ate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxy- benzoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.

2.4. Acrylates. for example ethyl α-cyano-β,β-diphenylacrylate, isooctyl α-cyano-β,β-diphe- nylacrylate, methyl α-carbomethoxycinnamate, methyl α-cyano-β-methyl-p-methoxy-cinna- mate, butyl α-cyano-β-methyl-p-methoxy-cinnamate, methyl α-carbomethoxy-p-methoxycin- namate and N-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

2.5. Nickel compounds, for example nickel complexes of 2,2'-thio-bis-[4-(1 ,1 ,3,3-tetrame- thylbutyl)phenol], such as the 1 :1 or 1:2 complex, with or without additional ligands such as n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel dibutyldithiocarbamate, nickel salts of the monoalkyl esters, e.g. the methyl or ethyl ester, of 4-hydroxy-3,5-di-tert- butylbenzylphosphonic acid, nickel complexes of ketoximes, e.g. of 2-hydroxy-4-methylphe- nyl undecylketoxime, nickel complexes of 1 -phenyl-4-lauroyl-5-hydroxypyrazole, with or without additional ligands.

2.6. Sterically hindered amines, for example bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(2,2,6,6-tetramethyl-4-piperidyl)succinate, bis(1 , 2,2,6, 6-pentamethyl-4-piperidyl)seba- cate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1 ,2,2,6,6-pentamethyl-4-pi- peridyl) n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the condensate of 1 -(2-hydroxy- ethyl)-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinic acid, linear or cyclic conden¬ sates of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-tert-octylami- no-2,6-dichloro-1 ,3,5-triazine, tris(2,2,6,6-tetramethyl-4-piperidyl)nitrilotriacetate, tetrakis- (2,2,6,6-tetramethyl-4-piperidyl)-1 ,2,3,4-butane-tetracarboxylate, 1 , 1 '-(1 ,2-ethanediyl)-bis- (3,3,5,5-tetramethylpiperazinone), 4-benzoyl-2,2,6,6-tetramethylpiperidine, 4-stearyloxy- 2,2,6,6-tetramethylpiperidine, bis(1 ,2,2,6,6-pentamethylpiperidyl)-2-n-butyl-2-(2-hydroxy-3,5- di-tert-butylbenzyl)malonate, 3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decan-2,4- dione, bis(1 -octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate, bis(1 -octyloxy-2,2,6,6-tetrame- thylpiperidyl)succinate, linear or cyclic condensates of N,N'-bis-(2,2,6,6-tetramethyl-4-piperi- dyl)hexamethylenediamine and 4-morpholino-2,6-dichloro-1 ,3,5-triazine, the condensate of 2-chloro-4,6-bis(4-n-butylamino-2,2,6,6-tetramethylpiperidyl )-1 ,3,5-triazine and 1 ,2-bis(3- aminopropylamino)ethane, the condensate of 2-chloro-4,6-di-(4-n-butylamino-1 ,2,2,6,6-pen- tamethylpiperidyl)-1 ,3,5-triazine and 1 ,2-bis-(3-aminopropylamino)ethane, 8-acetyl-3-dode- cyl-7,7,9,9-tetramethyl-1 ,3,8-triazaspiro[4.5]decane-2,4-dione, 3-dodecyl-1 -(2,2,6,6-tetrame- thyl-4-piperidyl)pyrrolidin-2,5-dione, 3-dodecyl-1 -(1 ,2,2,6,6-pentamethyl-4-piperidyl)pyrroli- dine-2,5-dione, a mixture of 4-hexadecyloxy- and 4-stearyloxy-2,2,6,6-tetramethylpiperidine, a condensation product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and 4-cyclohexylamino-2,6-dichloro-1 ,3,5-triazine, a condensation product of 1 ,2-bis(3-ami- nopropylamino)ethane and 2,4,6-trichloro-1 ,3,5-triazine as well as 4-butylamino-2,2,6,6-te- tramethylpiperidine (CAS Reg. No. [136504-96-6]); N-(2,2,6,6-tetramethyl-4-piperidyl)-n-do- decylsuccinimid, N-(1 ,2,2,6,6-pentamethyl-4-piperidyl)-n-dodecylsuccinimid, 2-undecyl- 7,7,9,9-tetramethyl-1-oxa-3,8-diaza-4-oxo-spiro[4,5]decane, a reaction product of 7,7,9,9- tetramethyl-2-cycloundecyl-1-oxa-3,8-diaza-4-oxospiro [4,5]decane und epichlorohydrin, 1 ,1 -bis(1 ,2,2,6, 6-pentamethyl-4-piperidyloxycarbonyl)-2-(4-methoxyphenyl)ethene, N,N'-bis- formyl-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine, diester of 4-methoxy- methylene-malonic acid with 1 ,2,2,6,6-pentamethyl-4-hydroxypiperidine, poly[methylpropyl- 3-oxy-4-(2,2,6,6-tetramethyl-4-piperidyl)]siloxane, reaction product of maleic acid anhydride- α-olefin-copolymer with 2,2,6,6-tetramethyl-4-aminopiperidine or 1 ,2,2,6,6-pentamethyl-4- aminopiperidine.

2.7. Oxamides. for example 4,4'-dioctyloxyoxanilide, 2,2'-diethoxyoxanilide, 2,2'-dioctyloxy- 5,5'-di-tert-butoxanilide, 2,2^,-didodecyloxy-5,5'-di-tert-butoxanilide, 2-ethoxy-2'-ethyloxani- lide, N,N'-bis(3-dimethylaminopropyl)oxamide, 2-ethoxy-5-tert-butyl-2'-ethoxanilide and its mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butoxanilide, mixtures of o- and p-methoxy-disub- stituted oxanilides and mixtures of o- and p-ethoxy-disubstituted oxanilides.

2.8. 2-(2-Hydroxyphenyl)-1 ,3.5-triazines. for example 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)- 1 ,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1 ,3,5-triazine, 2- (2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1 ,3,5-triazine, 2,4-bis(2-hydroxy-4-pro- pyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis- (4-methylphenyl)-1 ,3,5-triazine, 2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphe- nyl)-1 ,3,5-triazine, 2-(2-hydroxy-4-tridecyloxyphenyl)-4,6-bis(2,4-dimethylphenyi)-1 ,3,5-tri- azine, 2-[2-hydroxy-4-(2-hydroxy-3-butyloxy-propoxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5-tri- azine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxy-propyloxy)phenyl]-4,6-bis(2,4-dimethyl)-1,3,5- triazine, 2-[4-(dodecyloxy/tridecyloxy-2-hydroxypropoxy)-2-hydroxy-phenyl]-4,6-bis(2,4-di- meth vlphenyl)-1 ,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-dodecyloxy-propoxy)phenyl]-4,6- bis(2,4-dimethylphenyl)-1 ,3,5-triazine, 2-(2-hydroxy-4-hexyioxy)phenyl-4,6-diphenyl-1 ,3,5- triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1 ,3,5-triazine, 2,4,6-tris[2-hydroxy-4- (3-butoxy-2-hydroxy-propoxy)phenyl]-1 ,3,5-triazine, 2-(2-hydroxyphenyl)-4-(4-methoxyphe- nyl)-6-phenyl-1 ,3,5-triazine, 2-{2-hydroxy-4-[3-(2-ethylhexyl-1 -oxy)-2-hydroxypropyloxy]phe- nyl}-4,6-bis(2,4-dimethylphenyl)-1 ,3,5-triazine. 3. Metal deactivators. for example N,N'-diphenyloxamide, N-salicylal-N'-salicyloyl hydrazine, N.N'-bis(salicyloyl) hydrazine, N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl) hydrazine, 3-salicyloylamino-1 ,2,4-triazole, bis(benzylidene)oxalyl dihydrazide, oxanilide, isophthaloyi dihydrazide, sebacoyl bisphenylhydrazide, N,N'-diacetyladipoyl dihydrazide, N,N'-bis(salicyl- oyl)oxalyl dihydrazide, N,N'-bis(salicyloyl)thiopropionyl dihydrazide.

4. Phosphites and phosphonites. for example triphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl) phosphite, trilauryl phosphite, trioctadecyl phos¬ phite, distearyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,6- di-tert-butyl-4-methylphenyl)-pentaerythritol diphosphite, diisodecyloxypentaerythritol di¬ phosphite, bis(2,4-di-tert-butyl-6-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tris(tert- butylphenyl)pentaerythritol diphosphite, tristearyl sorbitol triphosphite, tetrakis(2,4-di-tert-bu- tylphenyl) 4,4'-biphenylene diphosphonite, 6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-di- benz[d,g]-1 _f3,2-dioxaphosphocin, 6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyl-dibenz[d,g]- 1 ,3,2-dioxaphosphocin, bis(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite, bis(2,4-di- tert-butyl-6-methylphenyl) ethyl phosphite, 2,2^,,2"-nitrilo[triethyltris(3,3^,,5,5'-tetra-tert-butyl- 1 ,1 '-biphβnyl-2,2'-diyl)phosphite], 2-ethylhexyl(3,3',5,5^,-tetra-tert-butyl-1 ,1 '-biphenyl-2,2'-di- yl)phosphite.

Especially preferred are the following phosphites:

Tris(2,4-di-tert-butylphenyl) phosphite (lrgafos*168, Ciba-Geigy), tris(nonylphenyl) phos¬ phite,

Very particular preference is given to tris(2,4-di-tert-butylphenyl) phosphite [lrgafos*168, Ciba-Geigy], bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite [lrgafos^β38, Ciba-Geigy, formula (G)] and 2,2^,,2"-nitrilo[triethyl-tris(3,3^,,5,5^,-tetra-tert-butyl-1 ,1^*-biphenyl-2,2'-diyl)- phosphite [lrgafos'12, Ciba-Geigy, formula (B)]. 5. Hvdroxylamines. for example, N,N-dibenzylhydroxylamine, N,N-diethylhydroxylamine, N,N-dioctylhydroxylamine, N,N-dilaurylhydroxylamine, N,N-ditetradecylhydroxylamine, N,N- dihexadecylhydroxylamine, N,N-dioctadecylhydroxylamine, N-hexadecyl-N-octadecylhy- droxylamine, N-heptadecyl-N-octadecylhydroxylamine, N,N-dialkylhydroxylamine derived from hydrogenated tallow amine.

6. Nitrones. for example, N-benzyl-alpha-phenyl-nitrone, N-ethyl-alpha-methyl-nitrone, N-oc- tyl-alpha-heptyl-nitrone, N-lauryl-alpha-undecyl-nitrone, N-tetradecyl-alpha-tridcyl-nitrone, N- hexadecyl-aipha-pentadecyl-nitrone, N-octadecyl-alpha-heptadecyl-nitrone, N-hexadecyl- alpha-heptadecyl-nitrone, N-ocatadecyl-alpha-pentadecyl-nitrone, N-heptadecyl-alpha-hep- tadecyl-nitrone, N-octadecyl-alpha-hexadecyl-nitrone, nitrone derived from N,N-dialkylhy- droxylamine derived from hydrogenated tallow amine.

7. Thiosynerαists. for example, dilauryl thiodipropionate or distearyl thiodipropionate.

8. Peroxide scavenαers. for example esters of β-thiodipropionic acid, for example the lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole or the zinc salt of 2-mercapto- benzimidazole, zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol tetrakis(β- dodecylmercapto)propionate.

9. Polyamide stabilisers, for example, copper salts in combination with iodides and/or phos¬ phorus compounds and salts of divalent manganese.

10. Basic co-stabilisers, for example, melamine, polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamides, polyurethanes, al¬ kali metal salts and alkaline earth metal salts of higher fatty acids for example calcium stea¬ rate, zinc stearate, magnesium behenate, magnesium stearate, sodium ricinoleate and po¬ tassium palmitate, antimony pyrocatecholate or zink pyrocatecholate.

11. Nucleating agents, for example, inorganic substances such as talcum, metal oxides such as titanium dioxide or magnesium oxide, phosphates, carbonates or sulfates of, pre¬ ferably, alkaline earth metals; organic compounds such as mono- or polycarboxylic acids and the salts thereof, e.g. 4-tert-butylbenzoic acid, adipic acid, diphenylacetic acid, sodium succinate or sodium benzoate; polymeric compounds such as ionic copolymers (ionomers).

12. Fillers and reinforcing agents, for example, calcium carbonate, silicates, glass fibres, glass bulbs, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, car¬ bon black, graphite, wood flour and flours or fibers of other natural products, synthetic fi¬ bers.

13. Other additives, for example, plasticisers, lubricants, emulsifiers, pigments, rheology additives, catalysts, flow-control agents, optical brighteners, flameproofing agents, antistatic agents and blowing agents.

14. Benzofuranones and indolinones. for example those disclosed in U.S. 4,325,863; U.S. 4,338,244; U.S. 5,175,312; U.S. 5,216,052; U.S. 5,252,643; DE-A-4316611 ; DE-A-4316622; DE-A-4316876; EP-A-0589839 or EP-A-0591102 or 3-[4-(2-acetoxyethoxy)- phenyl]-5,7-di-tert-butyl-benzofuran-2-one, 5,7-di-tert-butyl-3-[4-(2-stearoyloxyethoxy)phe- nyi]benzofuran-2-one, 3,3'-bis[5,7-di-tert-butyl-3-(4-[2-hydroxyethoxy]phenyl)benzofuran-2- one], 5,7-di-tert-butyl-3-(4-ethoxyphenyl)benzofuran-2-one, 3-(4-acetoxy-3,5-dimethylphe- nyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(3,5-dimethyl-4-pivaloyloxyphenyl)-5,7-di-tert-bu- tyl-benzofuran-2-one, 3-(3,4-dimethylphenyl)-5,7-di-tert-butyl-benzofuran-2-one, 3-(2,3-di- methylphenyl)-5,7-di-tert-butyl-benzofuran-2-one.

The additional additives and/or stabilizers are preferably added to the novel mixture compri¬ sing a) a secondary aromatic amine and b) a polyfunctional epoxide.

With the exception of the fillers, reinforcing agents (item 12 in the list) and glass fibres, the additional additives are added to the polyolefin recyclate in concentrations, for example, of from 0.01 to 10 %, based on the overall weight of the polyolefin recyclate to be stabilized.

The fillers and reinforcing agents (item 12 in the list) such as, for example, talc, calcium car¬ bonate, mica or kaolin, are added to the polyolefin recyclate in concentrations, for example, of from 0.01 to 40 %, based on the overall weight of the polyolefin recyclate to be stabilized. The fillers and reinforcing agents (item 12 in the list) such as, for example, metal hydroxides, especially aluminium hydroxide or magnesium hydroxide, are added to the polyolefin recyclate in concentrations, for example, of from 0.01 to 60 %, based on the overall weight of the polyolefin recyclate to be stabilized.

Carbon black as a filler is added to the polyolefin recyclate expediently in concentrations of from 0.01 to 5 %, based on the overall weight of the polyolefin to be stabilized.

Glass fibres as reinforcing agent are added to the polyolefin recyclate expediently in con¬ centrations of from 1 to 30 %, based on the overall weight of the polyolefin recyclate to be stabilized.

Further customary polyolefin additives can also be polymers which enhance the material properties of the previously damaged polyolefin, such as elastomers (impact modifiers) or compatibilizers (i.e. additives which improve compatibility).

Impact modifiers are homo- or copolymers which are able to modify brittle polyolefins in such a way that they retain impact strength even in the cold. Suitable examples are EPM polymers, EPDM polymers, ABR, BR or SBR graft polymers.

Examples of possible compatibilizers are copolymers, especially block copolymers, of sty¬ rene with butadiene with or without acrylonitrile. Further compatibilizers can be copolymers of ethylene and propylene with or without a third monomer component, such as butadiene, for example. Chlorinated polyethylene, or ethylene-vinyl acetate copolymers, are also sui¬ table as compatibilizers, a critical factor being of course the respective composition of the recyclate. Further suitable compatibilizers contain, in particular, polar groups, for example maleic anhydride-styrene copolymers or graft polymers containing acrylic acid groups.

The compatibilizers are preferably used in amounts of from 2 to 20 %, based on the overall weight of the polyolefin recyclate to be stabilized.

Also of interest is the novel process for stabilizing polyolefin recyclates against oxidative, thermal and/or light-induced degradation wherein further additives over and above at least one secondary aromatic amine and at least one polyfunctional epoxide are added, especial- ly UV absorbers and light stabilizers (item 2 in the list); amides of β-(3,5-di-tert-butyl-4-hy- droxyphenyl)propionic acid (metal deactivators, item 1.17 in the list); nucleating agents (item 11 in the list); fillers and reinforcing agents (item 12 in the list); and or compatibilizers.

Very special interest attaches to the novel process for stabilizing polyolefin recyclates against oxidative, thermal and/or light induced degradation wherein at least one compati¬ bilizer is added as a further additive in addition to at least one secondary aromatic amine and at least one polyfunctional epoxide.

The incorporation of the secondary aromatic amine and the polyfunctional epoxide, and of further additives if appropriate, into the polyolefin recyclate is accomplished by known methods, for example prior to or during shaping or else by applying the liquid, dissolved or dispersed stabilizer mixture to the polyolefin recyclate, with or without subsequent evapora¬ tion of the solvent. The stabilizer mixture can also be added in the form of a masterbatch, containing said stabilizer mixture in a concentration, for example, of from 2.5 to 25 % by weight, based on the weight of the polyolefin recyclate or virgin polyolefin material, to the polyolefin recyclates which are to be stabilized.

The novel stabilizer mixtures can be incoφorated in pure form or encapsulated in waxes, oils or polymers into the polyolefin recyclate which is to be stabilized.

The novel stabilizers, such as the secondary aromatic amine and the polyfunctional epoxide or mixtures thereof, can also be sprayed onto the polyolefin recyclate which is to be stabi¬ lized. They are capable of diluting other additives (for example the customary additives in¬ dicated above) and/or their melts, and consequently can also be sprayed together with these additives onto the polyolefin recyclate which is to be stabilized.

The polyolefin recyclates thus stabilized can be used for a very wide variety of purposes, for example for pipes, profiles and panels, such as insulating panels, pallets, cable insulation, sporting equipment, garden furniture, films, construction components, parts of vehicles and machines, containers of all kinds, such as bottles, or packaging material.

The polyolefin recyclate can also be employed in a form mixed with virgin polyolefin material or together with virgin material, for example in a coextrusion process. The invention additionally provides for the use of a mixture comprising a secondary aroma¬ tic amine and a polyfunctional epoxide for stabilizing polyolefin recyclates against oxidative, thermal and/or light-induced degradation. The preferences regarding the use correspond to those for the process.

The invention also provides a composition comprising a) a polyolefin recyclate, b) a secon¬ dary aromatic amine, and c) a polyfunctional epoxide. The preferences regarding the com¬ position correspond to those for the process.

The invention additionally provides polyolefin recyclates obtainable by the novel process.

The examples which follow illustrate the invention in more detail without limiting it thereto. As in the remainder of the description, parts and percentages are by weight unless stated otherwise.

Example 1 : Stabilizing polypropylene copolymer recyclate from battery cases.

In a Plasticorder from Brabender with a W 50 mixing chamber, regrind from used battery cases (polypropylene copolymer) is kneaded at a temperature of 210°C and at 40 revolu¬ tions/minute for 60 minutes together with the additives indicated in Table 1. The torque of the polymer is determined after 30, 45 and 60 minutes. The greater the number, the better the stabilization. After 60 minutes, the melt index (MFR) is measured (at 235°C under 2.16 kg in accordance with ISO 1 133). A large increase in the melt index denotes severe chain degradation, and therefore poor stabilization. The results are compiled in Table 1.

Table 1 :

Melt

Torque [Nm] after

Example Additives index

30 min. 45 min. 60 min. [g/10 min.]

1a^β) 1.4 0.6 0.3 >150

1b^β) 0.50 % lrganox*5057^a) 5.8 5.4 4.6 5.1

1c^β) 0.50 % Araldit'GY 260^b) 2.1 1.0 0.5 >150

1d^β) 0.50 % Araldit*PY 306^c) 2.3 1.0 0.5 >150

1e^β) 0.50 % Araldit'GT 6071 ^d) 1.9 0.9 0.4 >150

0.25 % lrganox*5057^a)

If 6.2 5.8 5.4 3.3 0.25 % Araldi GY 260^b)

0.25 % lrganox*5057^a) ig° 6.1 5.6 5.3 3.4 0.25 % Araldit*PY 306^c)

0.25 % lrganox*5057^a)

Ih 6.0 5.7 5.4 3.0 0.25 % Araldit'GT 6071 ^d)

a) lrganox^β5057 (Ciba-Geigy) is 4,4'-di-tert-octyldiphenylamine (see formula Ie). b) Araldit'GY 260 (Ciba-Geigy) is a liquid epoxide of the bisphenol A diglycidyl ether type. c) Araldit'PY 306 (Ciba-Geigy) is a liquid epoxide of the bisphenol F diglycidyl ether type [diglycidyl ether of bis(ortho/para-hydroxyphenyl)methane (Bisphenol F)]. d) Araldit'GT 6071 (Ciba-Geigy) is bisphenol A diglycidyl ether with an epoxide number of 2.15-2.22 Eq/kg and a softening range of 70-75°C. e) Comparison examples. f) Novel examples.

Example 2: Stabilizing mixed polyolefin recyclates.

In a plasticorder from Brabender with a W 50 mixing chamber, a mixture of used plastics consisting of about 80 % by weight of HD-polyethylene, about 15 % by weight of LD-poly- ethylene and about 5 % by weight of polypropylene is kneaded at a temperature of 190°C and at 40 revolutions/minute for 60 minutes together with the additives indicated in Table 2. The torque of the polyolefin mixture is determined after 20, 40 and 60 minutes. The larger the number, the better the stabilization. After 60 minutes, the melt index (MFR) is measured (at 235°C under 2.16 kg in accordance with ISO 1133). A large increase in the melt index denotes severe chain degradation, and thus poor stabilization. The results are compiled in Table 2.

Table 2:

Torque [Nm] after Melt

Example Additives index

20 min. 40 min. 60 min. [g/10 min.]

2a^d) 5.3 4.4 3.7 7.7

0.25 % lrganox*5057^a)

2b^β) 5.6 4.7 4.0 6.1 0.25 % Araldit^βCY 179^b)

0.25 % Irganox'δOδT¹

2c^β) 5.9 5.0 4.2 6.3 0.25 % Araldi EPN 1139^c)

a) lrganox^β5057 (Ciba-Geigy) is 4,4'-di-tert-octyldiphenylamine (see formula Ie). b) Araldit'CY 179 (Ciba-Geigy) is liquid 3,4-epoxycyclohexylmethyl 3,4-epoxy- cyclohexanecarboxylate, epoxide content 7.0-7.5 equivalents/kg. c) Araldit'EPN 1139 (Ciba-Geigy) is a liquid phenol novolak epoxy resin, epoxide content 5.6-6.8 equivalents/kg. d) Comparison example. e) Novel examples.

Claims

WHAT IS CLAIMED IS:

1. A process for stabilizing a polyolefin recyclate against oxidative, thermal or light-induced degradation, which comprises adding thereto at least one secondary aromatic amine and at least one polyfunctional epoxide.

2. A process according to claim 1 , wherein both the secondary aromatic amine and the polyfunctional epoxide are in liquid form.

3. A process according to claim 1 , wherein the secondary aromatic amine is a compound of the formula I

in which

Ri is hydrogen or Cι-C₂₅alkyl,

R₂ is hydrogen, C C^alk l or benzyl,

R₃ is hydrogen, C C₂₅alkyl, C₅-Cι₂cycloalkyl, benzyl, α-methylbenzyl or α,α-dimethylbenzyl;

or R₂ and R₃ together form a divalent group

R₄ is hydrogen, Cι-C_2Salkyl or benzyl,

R₅ is hydrogen or Cι-C₂₅alkyl,

R₆ is hydrogen, d-C^lkyl or benzyl,

R₇ is hydrogen, Cι-C₂₅alkyl, Cs-Cι₂cycloalkyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl or —

R,o is C₅-C₁₂cycloalkyl,

4. A process according to claim 3, wherein

Ri and R₂ independently of one another are hydrogen or Ci-CiβalkyI,

R₃ is hydrogen, C -Cι₈alkyl, C₅-C₈cycloalkyl, benzyl, α-methylbenzyl or α.α-dimethylbenzyl;

or R₂ and R₃ together form a divalent group

R^, R₅ and R₆ independently of one another are hydrogen or Cι-Cι₈alkyl,

R is hydrogen, Cι-Cι₈alkyl, C₅-C₈cycloalkyl, benzyl, α-methylbenzyl, α,α-dimethylbenzyl

or —

Rβ and R₉ independently of one another are hydrogen or Cι-Cι₈alkyl, and

Rio is C₅-C₈cycloalkyl,

5. A process according to claim 3, wherein R_1t R₄, R_s, R_β and R₈ are hydrogen.

6. A process according to claim 3, wherein Ri and R₂ are hydrogen, R₃ is hydrogen, C -Cι₂alkyl, cyclohexyl, benzyl, α-methylbenzyl or α.α-dimethylbenzyl; or R₂

and R₃ together form a divalent group

R₄, R₅ and R₆ are hydrogen,

R₇ is hydrogen, C₄-Cι₂alkyl, cyclohexyl, benzyl, α-methylbenzyl, α.α-dimethylbenzyl or

H /

-\ .

^R10

Rβ and R₉ are hydrogen, and

R₁0 is cyclohexyl, phenyl or β-naphthyl.

7. A process according to claim 3, wherein Ri, R₂, R₄, R₅, Re and R₈ are hydrogen,

R₃ is hydrogen or C₈alkyl,

H /

R₇ is C₈alkyl or — N and

^R10

Rio is phenyl.

8. A process according to claim 1 , wherein the polyfunctional epoxide is a compound which comprises epoxide radicals of the formula II

which are attached directly to carbon, oxygen, nitrogen or sulfur atoms, in which R_{1 t} and Rι₃ are both hydrogen, Rι₂ is hydrogen or methyl and n is 0; or in which Ru and Rι₃ together are -CH₂CH₂- or -CH₂CH₂CH₂-, Rι₂ is then hydrogen, and n is 0 or 1.

9. A process according to claim 1 , wherein the polyfunctional epoxide is a difunctional epoxide.

10. A process according to claim 1 , wherein the polyfunctional epoxide is a bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, liquid cycloaliphatic epoxy resin or phenol novolak epoxy resin.

11. A process according to claim 1 , wherein from 0.01 to 5 parts of the secondary aromatic amine and from 0.01 to 10 parts of the polyfunctional epoxide are used per 100 parts of polyolefin recyclate.

12. A process according to claim 1 , wherein the polyolefin recyclate is a copolymer recyclate of mono- and diolefins.

13. A process according to claim 1 , wherein the polyolefin recyclate is a polypropylene copolymer recyclate or polyethylene copolymer recyclate.

14. A mixture comprising a) a secondary aromatic amine and b) a polyfunctional epoxide, the weight ratio of the components a): b) being from 10:1 to 1:10.

15. The use of a mixture comprising a secondary aromatic amine and a polyfunctional epoxide for stabilizing polyolefin recyclates against oxidative, thermal or light-induced degradation.

16. A composition comprising a) a polyolefin recyclate, b) a secondary aromatic amine, and c) a polyfunctional epoxide.

17. A polyolefin recyclate obtainable by a process according to claim 1.