AU629804B2

AU629804B2 - Polyolefin molding composition for long term contract with extractive media

Info

Publication number: AU629804B2
Application number: AU26956/88A
Authority: AU
Inventors: Klaus Lotzsch; Gerhard Pfahler
Original assignee: Hoechst AG
Current assignee: Clariant Produkte Deutschland GmbH
Priority date: 1987-12-18
Filing date: 1988-12-16
Publication date: 1992-10-15
Anticipated expiration: 2008-12-16
Also published as: DE3742933A1; JPH01201345A; EP0324106B1; ZA889396B; DE3851047D1; BR8806675A; HK1007153A1; NO885505D0; JP2680649B2; CA1330675C; NO302530B1; ATE109812T1; ES2060640T3; AU2695688A; EP0324106A1; NO885505L

Abstract

A polyolefin moulding composition which has excellent chemical stability on long-term contact with extracting media contains, as stabilisers, a symmetrical triaryl phosphite and an ester of 3,3-bis(3'-t-butyl-4'-hydroxyphenyl)butanoic acid.

Description

WCFAA too HOECHST AKTIENGESELLS

AFT

Prokurist Authorized Signato y ppa. Isenbruck t.V. Lapice PAT 510 1'4

I

COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952469 COMPLETE SPECIFICATION

(ORIGINAL)

Form Class I t. Class Application Number: Lodged: Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name of Applicant: Address of Applicant: Actual Inventor: Addrcss for Service: HOECHST AKTIENGESELLSCHAFT 45 Bruningstrasse, D6230 Frankfurt/Main Federal Republic of Germnany GERHARD PFAHLER and KLAUS LOTZSCH EDWD. WATERS SONS, 50 QUEEN STREET, MELBOURNE, AUSTRALIA, 3000.

Complate Specification for the invention entitled: POLYOLEFIN MOLDING FOR LONG TERM CONTACT WITH EXTRACTIVE MEDIAA The following statement is a full description of this invention, Including the best method of performing it known to us HOECHST AKTIENGESELLSCHAFT HOE87/F 377 Dr.DA/rh Description PolyoLefin molding Le \w1 for Long term contact with extractive media The present invention relates to molding Com An based on polyolefins which have a particular chemicaL stability in contact with extractive media.

It is known that polyolefins must be protected by suitable stabilizing systems against oxidative degradation during production, processing and use. Stabilizer systems of this kind comprise for example a phenolic antioxidant, which in particular must ensure the long-term S 15 stability in use of the finished component, and one or more costabilizers, which control the processing stability and to some extent enhance the effect of the phenolic component synergistically.

20 A stabilizer combination of this kind which has been *.Oo disclosed comprises a phenolic antioxidant with a symmetrical triaryl phosphate of the formula

R

I

R

1 25 R 2 0 -P R 3 3 where the radicals R may be various aliphatic or aromatic radicals and R 2 and R may additionally be hydrogen (cf. US-B-4,187,212). In particular tris-(2,4-dit-butylphenyl) phosphite in association with a phenolic antioxidant is often used in practice. These frequently used stabilizers are however not suitable for all applications. In many instances the mclding compounds which are stabilized in the manner described come fit U"! 1_ S 2 into contact with liquid media in use. Thus it is necessary that the stabilizers added to the molding \EB= #pow*i have sufficient chemical resistance to the individual contact media. Where this is not the case the finished component fails in long-term use long before the time which can be inferred from laboratory tests carried out under dry conditions. For components of this kind such as water pipes, underwater cables or tanks a considerable danger results.

114 15

I

It 4 ti Ip 4 tl( The object was to provide a polyolefin molding \Ta 4e10m Iwhich loses as little chemical stability as possible in long-term contact with extractive media.

It has been found that this .object can be achieved by a polyolefin molding 'Bef W \which contains a particular organic phosphite and a particular phenolic compound.

it I C I 41 4 II at The invention thus relates to a polyolefin molding pvEFd- comprising 90 to 99.98 by weight of an olefin polymer, 0.01 to 5 by weight of a triaryl phosphite and 0.01 to 5 by weight of a phenolic antioxidant, wherein the triaryl phosphite is one of the type shown in 25 formula I 441114

I

1(

R

2 p where R is a t-butyl, 1,1-dimethylpropyl, cyclohexyl- or a phenyl group and 4 R 2 and R are identical or different and are a hydrogen atom, a methyl, t-butyl, 1,1-dimethyl- -3propyl, cycLohexyL, or phenyL group and the phenolic antioxidant is an ester of 3,3-bis-(3'jtbuty L-4'-h)'droxypheny L)-but ano ic a c id o f the f o rmu La

OH

F t-C 4H9 0 CHH -C4

C

3 CH2 -C 0 ~~OH t49n(I L I where R~ is a Cl-Cl 2 -aLkyL radicaL or a Cl-Cl 2 -aLkyLene radicaL and n is 1 or 2.

The poLyoLefin in the moLding =Op*U4=_\ac cord ing to the invention can for exampLe be one of the poLymers men- J o tioned as follows: 1 Polymers of mono- or dlioLef ins, for exarnpLe poLyethylene (which if necessary may be cro,,;sLinked), polypropylene, poLy isobutyLene, poLy-1-buteie, poLymethyL-1-pentene, poLyisoprene or poLybutadiene as *o p.

so*,,well as polymers of cycLooLefins such as for exampLe f rom cycLopentene or nz'rbornene.

2. Mixtures of the polymers mentioned in 1 eg. mixtures of polypropylene with poLyisobutyLene, 3. CopoLymers of mono- and dioLefins with one another or with other vinyl monomers such as for example ethyLene/ pi-opyLene copoLymers, p ropy Lene/ I1-butene copoLymers, propyLene/ isobutytene copoLymers, ethyLene/1-butene NL.4copoLymers, propyLene/ butadiene uu.poL ymers,

UE

4 -4isobutyLene/isoprene copolymers, ethyLer'e/aLkyL acryLate copolymers, ethyLene/alkyl methacryLate copoLymers, ethylene/vinyL acetate copolymers or ethylene/acryL ic acid copolyrners and their salts (ionomers), as well as.

terpolymers of ethyLene with propyLene and a dliene, such as hexadiene, dicycLopentadiene or ethylidlenenorbornene.

The proportion of polyolefin in the moLding~ according to the invention is in the range 90 to 99.98, preferably in the range 98 to 99.92% by weight.

The molding contains as stabitizer an organic phosphite and a phenoLic antioxidlant.

The organic phosphite is a triaryL phosphite of the f ormula 010 R2 Q an P 3(rI)nia o ifrn ndaeahd 00 g is ama eL t-buty, 1,1-dimethypropy, cycl rphLo group andey rop rs(,4d--uyphnL hs phite is particularLy preferred.

The phenoLic antioxidlant is an ester of 3,3-bis-(3't-butyL-4-hydroxyphenyL)butanoic acid of the formula II CjIA.

H

O t-C 4H9 0; 4 CH 3 C-CH 2-C-O 0_R 0 t-C 4H 9

OH

n where R4represents a Cl-C 12 -aLkyL radicaL or a lC2 aLkyLene radlicaL and n is 1 or 2. PreferabLy, Ris a

C

2

-C

4 -aLkyLene radlical, particularLy a C 2 -aLkyLene C415 radic aL.

c The proportion of -the phosphite and of the phenoLic anti- :1 oxidant in the moLding ajccording to the invention is in the range 0.01 to 5, preferabLy 0.04 to 1% by weight for the phosphite and to 5, preferabLy 0.04 to 1% by weight for the phenoLic antioxidlant.

0 If required the molding accordling to the invention may contain other additives, such as for example: 1. Antioxidants 1.1 ALkyLated monophenoLs 2,6-Di-tert.-butyL-4-methyLpheno,, 2-tert.-butyL-4,6dimethyLphenoL, ?,6-di-tert.-butyk-4-ethyLphenoL, 2,6-ditert.-butyL-4-n-butyLphenol, 2,6-0l-tert butyL-4-i-butyLphenol, 2,6-di-cycLopentyL-4-methyLphenoL, 2-(a-methyLcyclohexyL )-4,6-dimethyLphenoL, 2,6-di-octadecyL-4-methyLphenol, 2,4,6-tri-cyc LohexyLphenoL, 2,6-di-tert.-butyL-4metitoxymethyLphenoL.

1.2 ALkytated hydroquinones 2,6-D i-tert.-butyL-4-methoxyphenoL, PLLII h yd ro qu ino ne 2,5-di-tert amyL-hydroqu inane, ta 4 atla 44 att r a a at ~a at a t 4 a ta a a a t a; a4 a 4 a a a; a Ba a; aaa t a a a 14 a a 4 at...

SaaB a 4 -6- 2,6-diphenyL-4-octadecycLooxyphenoL.

1.3 Hydroxytated diphenyt thioethers 2,2'-Thio-bis-(6-tert.-butyL-4-iethyLphenoL), 2,2 '-th jobis-(4-octyLphenoL), 4,4' -thio-bis-(6-tert.-butyL-3-methyLphenol), 4,4'-thio-bis-(6-tert.-butyL-2-methyLphenoL).

1.4 Atkytidene bisphenoLs 2,2'-MethyLene-bis-(6-tert.-butyt-4-methyLphenoL), 2,2'methyLene-bis-(6-tert.-butyL-4-ethytphenoL), 2,21-methy- Lene-bis--E4-methyL-6-Cct-methyLcycLohexyL )phlenoLJ, 2,2'rethyLene-bis-C4-methyL-6-cycLohexyLphenoL.), 2,2'-methy- Lene-bis-(6-nonyL-4-methyLphenoL), 2,2'-methyLene-bis- (4,6-di-tert.-butyLphenoL), 2,2'-ethyL idene-bis-(4,6-di- 15 tert.-butyLphenoL), 2,2'-ethyL idene-bis-(6-tert.-butyL- 4-isobutyLphenoL), 2,2'-methyLene-bis-E6-(ca-methyLbenzyL 4-nonyiphenoL], 2,2'-methyLene-bisE6-a,i--dimethyLbenzyL)- 4-nonyiphenoL J, 4,4'-nethyLene-bis-(2,6-di-tert butyLphenoL), 4,4'-methyLene--bis-(6-tert.-butYL-2-methyLphenoL 1,1-bis-(5-tert.-buityL,-4-hydroxy-2-methy!,phenyL )butane, 2,6-di--(3-tert bijtyL-5-methyL-2-hydroxybenzyL )-4-methyLphenol, 1,1,3-tr is-(5-tert butyL-4-hydroxy-2-methyLphenyL )butane, 1,1-bis-C5-tert.-butyL-4-hydroxy-2-methyLphenyL )-3-r-dodecyLmercaptobutane, di-(3-tert.-butyL-4- 25 hydroxy-5-methyLphenyL )dicycLopentadiene, di-E2-(3'-tert.butyL-21-hydroxy-5'-methyLbenzyL)-6-tert.-butyL-4-methyLphenyl terephthaLate.

1.5 BenzyL compounds 1,3,5-Tri-(3,5-di-tert.-butyL-4-hydroxybenzyL )-2,4,6-trimethyLbenzene, di-(3,5-di-tert.-butyL-4-hydroxybenzyt suLfide, isooctyL (3,5-di-ter't.-butyL-4-hydroxybenzyL merceptoacetate, bis-(4-tert butyL-3-hydroxy-2,6-dimethyLbenzyL )dithioL ter-ephthalate, 1,3,5-tris-(3,5-ditert.-butyL-4-hydroxybenzyL) isocyanurate, 1,3,5-tI'ris-(4tert.-butyL-3-hydroxy-2,6-diiethyvLbenzyL) isocyanurate, dioctadecyl (3,5-d'-tert.-butyL-4-hydroxybenzyL )phosphonate, catc jun monoethyt (3,5-di-tert.-butyL-4-hydroxybenzyL) phosphonate.

S 1.6 Acylaminophenots 4-hydroxy--Laur an i Llce, 4-hydroxy-ste aran iL ide, 2,4-bisoctyLmercapto-6-(3,5-di-tert.-butyL-4-hydroxyanitno)str iaz ine, oc tyL N-(3,5-d i-te, t but yL-4-hydroxy-phenyL carbamate.

1.7 Estert of 0-(3,5-di-tert.-butyt-4-hydroxyphenyL)propior~ic acid with monohydnic or poLyhydric aLcohoLs, such as for exampL-: with methanoL dli'?thyLene gLycoL o c tadle ca no L triethyLene gLycoL 1,6-hexanedioL pentaerythr itol neopentyL gLycot tris-hydroxyethyL isot th io-dli e th y Ce ne gLycoL cyanurate 0,15 di-hydroxyethyL (oxaLyLf4 1.8 Esters of 8-CS-tert.-butyL-4-hydroxy-3-methyLphenyL)propionic acid withi monohydric or polyhydric aLcohols, such as for exampLe with methanoL dliethytene gLycoL 'r ocaeao retyeegy o c 1tityeegyo I t tI( t di-hydroxyethyL(oxatyL- 1.9 Amides of 0-( 3 ,5-di-tert.-butyL-4-hydroxyphenyL.

propionic acid, such as -for exampLe N,'d-35d-et-uyL4hdoyhn rpoy)hexarethyLenediamine, N,N -di-(3,5-dli-tert.-butyL-4hydroxyphenyipropionyL )-trimethyLenediamine, di-tert.-butyL-4-hydroxyptenyLpropionyL )-hydrazine.

2. UV adsorbers and Light stabitizers 2.1 2 2 1-HydroxyprethyL)-benzotriazotes, such as for -8example the 5'-methyL-, 3',5'-dli-tert.-butyL-, butyL-, 1,1,3,3-tetramethyLbutyL 5-chLoro-3'U,5 '-di- 41-octoxy-, 3',5'-di-tert.-amyL- and 3',5'-bis-(ct,c-dimethyLbenzyL) derivatives.

2.2 2-Hydroxybenzophenones, such as for example the 4hydroxy-, 4-methoxy-, 4-octoxy-, 4-decyLoxy-, 4-c'edecyLoxy-, 4-benzyLoxy-, 4,2',4'-trihydroxy- and 2'-hydroxy-4,4'dlimethoxy derivatives.

2.3 Esters of optionally substituted benzenecarboxyLic acids, such as for example 15 4-tert.-butyL-phenyL saLicyLate, phenyL saLicyLate, octylf 15 phenyL salicyLate, dibenzoyL resorcinoL, bis-(4-tert.fitj butyLbenzoyL)resorcinoL, benzoyL resorcinoL, 2,4-di-tert.- 4 butyLphenyL 3,5-di-tert.-butyL-4-hydroxybenzoate and hexa- ~cdecyL 3,5-di-tert.-butyL-4-hydroxybenzoate.

2.4 Acrytates, such as for example ethyl ct-cyano-a,a-diphenyLacryLate or isooctyL c-cyano-a,a 0-diphenylacryLate methyl (x-carbomethoxy-cinnamate, methyl 1 t I a-cyano-0--methyL-p-methoxy-cinnamate or butyL c-cyano-Bmethyl-p-methoxy-c innamate, methyl ca-carbomethoxy-p-meth- S 25 oxy-cinnamate and N-(O-carbomethoxy-B-cyanovinyL)-2-methyLindloLine.

2.5 NickeL compounds, such as for example nickel complexes of 2,21-thio-bis-4-( 1, 1,3,3-tetramethyLbutyL)-phenoLJ, such as the 1:1- or 1:2 complex, which may have additional Ligands such as n--butyLamine, triethanoLamine or N-cyc LohexyL-diethanoLamine, nickel aLkyLdithiocarbamates, nickel salts of monoaLkyL esters of 4-hydroxy-3,5-di-tert.-butyL-benzyLphosphonic acid such as those from the methyl or ethyl esters, nickel complexes of ketoximes such as of 2-hydroxy-4-methyLphenyL-undecyL kitone oxime and nickel complexes of 1-phenyl-4-LauroyL-5hydroxypyrazoLe, which may have additional Ligands.

9- 2,6 StericatLy hindered amines, such as for example b is- (2 ,2 ,6 6- te t ra met h y Lp ipe r idl se ba ca t e, b is 1, 2, 2, 6 6 pentamethyLpiperidyL) sebacate bis-(1,2,2,6,6-pentamethylpiperidyL)(n-butyL-3,5-di-tert.-butyL-4-hydroxybelzyLmalonate, condensation product from 1-hydroxymethyL-2,2,6, 6-tetramethyl-4-hydroxypiperidine and succinic acid, condensation product from N,N'-C2,2,6,6-tetramethyL-4-p iperidyL )-hexamethyLenedi amine and 4-tert.-octyLamino-2,6-dichloro-1,3,5-s-traizime, tris-(2,2,6,6--tetramethyL-4-pi peridyl itr i Lo tr i acetate, tetraki s-(2,2,6,6-tetramethyL-4piperidyl )-1,2,3,4--butane-tetracarboxyL ic acid and, 1,1'- (1,2-ethanediyL)-bis-(3,3,5,5-tetramlethyL-piperazinone).

2.7 OxaLyLdiarmides, such as for exampLe 15 4,4'-di-octyLoxy-oxaniL ide, 2,2'-di-octyLoxy-5,5'-di-tert.butyL-oxanil ide, 2,2'-djdodecyLoxy-5,5'-di-tert.-butYLoxanilidle, 2-ethoxy-2'-ethyL-oxani Lide, N,NI-bis-(3-dimethyLaminopropyL )-oxaLamide, 2-ethoxy-5-tert.-butyL-2'ethyLoxanilide and a mixture of the Latter with 2-ethoxy- 2'-ethyL-5,4'-di-tert.-butyL-oxaniLide, mixtures of orthoand para-methoxy- as weLL as of o- and p-ethoxy-di-substituted oxaniL ides.

44 04 E *441 o

I

'Vt a O t

IL~

41 t 4 t 41 4* *4 44 4 49 a 0 3. MetaL deactivators, such as for example N ,N I- d iph en y Lo xaLy Ldli a m id e, N -sa L ic y La L sa L i cy Lo y Lh ydcr a z ine, N,NI- b is sa L i cy Lo y L-h ydlr a z in e, N b is ,5 di-tert.-butyL-4-hydroxyphenyLpropionyL )-hydrazine, 3-saL icyLoyL-amino-1,2,3-tr iazoLe and bis-ben eyL idene-oxaLyL dlihydrazidle.

4 44 44 4 4444 44 4 I 4. Phosphites and phosphonites, such as f or example triphenyL phosphite, diphenyLaLkyt phosphites, phenyLdiaLkyL phosphi tes, tr i-(nonyLphenyL phosph ite, tri LauryL phosph ite, trioctadlecyl phosphi te, distearyL-pentaerythritoL dliphosphite, tris-(2,4--di-tert.-butyLphenyL) phosphite, dliisodecyLpentaerythritoL dliphosphi te, dli-(2,4-dli-tert.-butyLphenyt )-pentaerythritoL dliphosphite, tristearyL-sorbitoL triphosphite, tetrakis-(2,4-di-tert.-butyLphenyL biphenylene diphosphonite and 10 3,9-bis-(2,4-di-tert.-butyLphenoxy-2,4,8,10-tetraoxa- 3 9 Peroxide destroying compounds, such as for example esters of B-thio-dip.opionic acid, for example the Lauryl, stearyl, myristyl or tridecyl esters, mercaptobenzimidazole, the zinc salt of 2-mercaptobenzimidazole. zincalkyl-di-thiocarbamates, dioctadecylsulfide, pentaerythrityl-tetrakis-(8-dodecyLmercapto)-propionate.

15 ri t 4 4

I.'

30 44 or 44 2' 4 .30 6. Basic costabilizers, such as for example melamine, polyvinylpyrroLidone, dicyandiamide, triallyl cyanurate, urea derivatives, hydrazine derivatives, amines, polyamines, polyurethanes, alkali metal saLts and alkaline earth metal salts of higher fatty acids, for example calcium stearate, zinc stearate, magnesium stearate, sodium ricinoleate, potassium palmitate, antimony pyrocatecholat2 or tin pyrocatecholate.

7. Nucleating agents, such as for example 4-tert,-Butylbenzoic acid, adipic acid and diphenylacetic acid.

8. Fillers and reinforcing agents, such as for example Calcium carbonate, silicates, glass fibers, asbestos, talc, kaolin, mica, barium sulfate, metal oxides and hydroxides, carbon black, graphite.

9. Other additives, such as for example Plasticizers, lubricants, emulsifiers, pigments, optical brighteners, flame retardants, antistatic agents, blowing agents.

The production of the molding r p according to the invention is car'ried out by customary methods. This may be for example by incorporating stabilizers and other additives if necessary by procedures which are customary in the art before or during molding, or also by coating the polymer with the dissolved or dispersed p if i I ~r r li; li;i ~l i~ 11 necessary evaporating the solvents afterwards. The stabi- 1 lizers can also be added when producing the molding iefpmmnd in the form of a master batch, which may contain these products at a level of about 2.5 to 25% by weight.

An addition before possible crosslinking is also possible.

The different supplementary additives of groups 1 to 7 mentioned previously are added to the molding compound according to the invention in an amount of from 0.01 to 10, preferably 0.01 to 5% ,by weight, based on the total weight of the molding crep'rd-. The proportion of additives from groups 8 and 9 is in the range 1 to 80, preferably 10 to, 50% by weight, based on the total molding tz Com 19ooS The polyolefin molding according to the invention is remarkable for having a very good Long term stability in the presence of extractive media. The ester St of 3,3-bis-(3'-t.-butyl-4'-hydroxyphenyl)-butanoic acid to be used according to the invention is extraordinarily stable to hydrolysis, not only as the pure substance, but also in the presence of the triaryl phosphite of formula I.

In this instance the esters of 8-(3,5-di-t.-butyl-4-hyi, t25 droxyphenyl)-propionic acid which are very often used as phenolic antioxidants show a clear tendency to hydrolyse when in contact with the plastic containing them due to the humidity of the surrounding air. A thin layer chro- S matogram shows that on storage the phenol in the polymer is systematically altered and upon extraction with water degradation products enter the contacting medium. In the presence of a phosphite.of formula I this splitting of the stabilizer into smaller degradation products is drastically accelerated and is more pronounced the longer the storage time.

Com p&lz:\oYs The molding d according t the invention is par- AL4, ticularly suitable for producing objects, which remain in S f long-term contact with extractive media, in particular

/I

ii I~ ~I:i i- i~ r 12 water, such as for example pipes, tanks, cable sheathing, small containers, nets, ropes or sheet-like fabrics.

The :oLLowing examples are intended to explain the invention further.

Example 1 Radioactive labeled compourds9 tetrakis-E3-(3,5-di-t.-butyL- 4 -hydroxyphenyl)-propionyoxy-methyeneJ-methane-(propionyl-1- 14 C) pentaerythritoL ester of butyl-4-hydroxyphenyLpropionic acid A01) and qa- -RAwo-- t ethytene-di-(3,3-bis t -bu y 4-hydroxyphernyL)butanoate)-butanoy-3- 4 C) 3,3-bis-(-t.-buty-4hydroxyphenyl)-butanoic acid AOII) were produced.

It The incorporation of 14C Labeled antioxidants in polyethylene powder was carried out in a laboratory rotary evaporator (Heidolph). The antioxidants were first dissolved in acetone; the solvent was stoutwy removed by distillation under vacuum. The following were mixed in this way: 498.5 1 ethylene copolymer (unstabilized), denrity 0.95 g/cm MFI 190/5 0.4 g/10 minutes 1 g calcium stearate 0.2%) rS 14 0.5 g 1 labeled antioxidant The production of test pieces was carried out on a pilot plant sc51e on an injection molding machine, ot the Arburg Allrounder type, With a plasticizing screw of constantly increasing root diameter with 20 flight intervals and an electrically heated injection unit. circular test pieces, of diameter 39 mm (in particular v es also 12 mm) were punched out from the drop shaped injection moldings (2.3 y, 1 mm thickness) using a press with a rotational assembly.

The test pieces were supported in a spiral of silvered wire nd were complete ly immersed in this apparatus in a glass weighing vesset containing the Water test medium.

13 fter certain interva1s samples of the Liquid were removed and the ratioactivity was measured with a Liquid scintiLlation counter. The migra tion was calculated from this.

The results are summarized in TrabLe 1.

L 44 t I r 9s .4 9 9, C C .9 .9.9 S C 9 .9 9. 9 4 9 9

C

C 9 .999 @04 9 9 009

C

C C a a

C

a 0* 9 9.9 .9 SC #4* S Ct 0 0 9* CC 9 .9 4 t~ C .9 4 4, 44090 .949 C CC C 4 Extraction period (days) TABLE 1 Migration (mg/dm 20 months immediately after production of test specimens 0.1% AOI 0.1% AOII 0.1% AOI 0.1% AOII 0.05% AOI 0.05% AOII 0.05% AOI 0.05% AOPI 1 0.05% AOII 0.05% AOPI 24 monihs 0.1% AOI 0.1% AOII L 4 0.043 0.005 0.011 0.007 0.084 0.131 0.006 0.012 0.033 0.064 0.097 0.002 0.004 0.006 0.021 0.025 0.010 0.013 0.175 0.014 0.031 0.037 0.015 0.041 0.016 0.048 0.017 0.066 0.019 0.129 0.008 0.170 0.010 0.062 0.116 0.171 0.220 0.285 0.342 0.402 0.002 0.004 0.006 0.007 0.009 0.011 0.015 0.059 0.120 0.181 0.234 0.005 0.009 0.014 0.016 0.239 0.300 0.373 0.018 0.021 0.025 0.206 0.250 0.012 0.015 0.377 0.454 0.026 0=032 Migration oi antioxidants from HDPE into water at 49°C as a function of the storage time of test specimens AOPI tris-(2,4-di-t.-butylphenyl) phosphite frequently used stabilizers are however not suitaoie Tor all applications. In many instances the molding compounds which are stabilized in the manner described come C -I ~'ILilLi I II C1 71( -r ma r- ^*alt t 1 ti:I lll~-~PI P IIIIIIC ~-1~1 4 I i4 15 Example 2 Test pieces were produced as in Example 1 but with the following recipe: 93.75 parts of ethylene copolymer as in Example 1, 6.25 parts of pigment concentrate (40% by weight carbon black).

0.2 part of calcium stearate, 0.05 part of phenolic antioxidant, 0.05 part of tris-(2,4-di-tert.-butylphenyL)-phosphite.

The test pieces were stored in a wter bath at 80 0 C for different periods. Small samples were taken subsequently.

Using a DSC apparatus (Differential Scanning Calorimetry) the period at 2000C was determined at which an exothermic 15 reaction in an oxygen stream at 50 cm /minute indicated exhaustion of the stabilizing system. This period is designated the oxidation induction time The re- Ssults are presented in Table 2. It is noticeable that the diminution of the OIT for the stabilizer combination according to the invention of AO II with phosphite-(I) after contact with water is less than that of AO I.

'4r: 0r I 4 4 Table 2 Phenolic antioxidant OIT in minutes after sto.age in water (80 0

C)

for 0 hours 500 hours 1,000 hours 4*#4 I 4 0.05 part of AO II 0.05 part of AO I Example 3 Test specimens were produced as described in Example 1 but with the following recipe: 100 parts of propylene homopolymer (density 0.90 g/cm 3 (at 23 0 melt index 230/2.16: 2 g/10 minutes) 0.2 part of calcium ste-rate 0.1 part phenolic an io.idant (AO II or AO I).

Iphenyl group and Rand R3are identical or different and are a hydrogen atom, a methyl, t-butyL, 1,1-dimethyL- V J I, 16 The results are presented in Table 3.

TabLe 3 Migration of AO 11- 14 C and AOC -4 from into water at 49 0

C

polypropylene EL apsed time d ays Quantity of migrated stabilizer in jig/cm 2 AO I I 0.004 0.007 0.010 0.012 0.014 0.019 0.026 AO I 0.018 0.040 0.055 0.071 0.091 0. 135 0. 194 4 A I 4*44 *44 4 .4 I I i~

I

4 I It I 4 k~ *4 4 4 A tI .1 I 44 4 41 4 11444

I

j 1~ 4, 4*44

A

4,411% A

Claims

1. A liquid conduit resistant to corrosion against long term contact with extractive media traversing said conduit, said liquid conduit comprising: to 99.98% by weight of an olefin polymer, 0.01 to 5% by weight of a triaryl phosplhie, and 0.01 to 5% by weight of a phenolic antioxidant, wherein the triaryl phosphite is one of type shown in formula i 0 P I r I o r a t a L C I (I L I) I s D *O r o r r where R1 is a t-butyl, 1,1-dimethylpropyl, cyclohexyl or a phenyl group and R2 and R3 are identical or different and are a hydrogen atom, a methyl, t-butyl, 1,1- dimethylpropyl, cyclohexyl, or phenyl group and the phenolic antioxidant is an ester of 3,3-bis-(3'-t-butyl-4'-hydroxyphenyl)- butanoic acid of the formula ii *t-C 4 H 9 0 O II CH 2 C 0 R 4 where R4 is a C 1 -C 12 -alkyl radical or a Ci-C12-alkYlene radical and n is 1 or 2. i 1.Z ALKytatea nyaroquiiiwiuca 2 ,6-Di-tert.-butyL-4-ethoxyphenoL, hydroquilofe, 2,5-di-tert amy L-hydroqu inone, 18

2. A liquid conduit as claimed in claim 1 wherein the triaryl phosphite is t ri Is (2,4 4- di-t-butyl-phenyl) phosphite and the phenolic antioxidant is the glycol ester of 3,3- bis-(3'-t-butyl-4'-hydroxyphenyl)- butanoic acid. A method of producing objects which remain in long term contact with extractive media comprising admixing a moulding composition comprising to 99.98% by weight of an olefin polymer, O001 to 5% by weight of a triaryl phosphtp, and 0.01 to 5% by weight of a phenolic antioxidant, whorein the triaryl phosphite is one of type shown in formula i 0 F 4 4 0 0 OS .4 0 *4 where R1 is a t-butyl, 1,1-dimethyipropyl, cyclohexyl or a phenyl group and R 2 and R3 are identical or different and are a hydrogen atom, a methyl, t-butyl, 1 1 dimethyipropyl, cyclohexyl, or phenyl group and the phenolic antioxidlant is an ester of 3,3-bis-(3'-t-butyl-4'-hydroxyphenyl)- butanoic acid of the formula ii OH t-0 4 H- 9 0. 0 CH 3 C -CH 2 C-0- R 4 (11) 0 t-C 4 H- 9 ter t .butyL3hydroxy-2,6-d imet hyLben ZYL J1 SULyollui d ioc tadecyl.

3 5 -d itert .butyL-4hydroxybenzy L )ph osphoflate calcium nonoethyl 3 5 -di-tert.bUtyL-4hydroxybenzyL) phosphoflate. 19 where R4 is aC,-C 12 -alkyl radical or aCi -C12-alkylene radical and n is 1 or 2 with conventional excipients and additives used in plastic moulding processes.

4. Amethod asclaimed in claim 3 wherein the triaryl phosphite is tris- (2,4-di-t- butyl-phenyl) phosphite and the phenolic antioxidant is the glycol ester of 3,3 -bis-(3' t-butyl-4'-hydroxyphenyl)- butanoic icid.

A polyolefin moulding composition comprising to 99.98% by weight of an olefin polymer, 0.01 to 5% by weight of a triaryl phosphite and 0.01 to 5% by weight of a phenolic antioxidant, wherein the triaryl phosphile is one of the type shown in formula i 0- -P 44 4 4 C 44 4 4 a a 4 444 4 4444 44 4 C 4~ 4' Cr CC r CC c CCC. CC C 4 C where Ri is a t-butyl, 1 ,1-dimethylpropyl, cyclohexyl or a phenyl group and R 2 and R3 are identical or different and are a hydrogen atom, a methyl, t-butyl, 1 1 dimethylpropyl, cyclohexyl, or phenyl group and the phenolic a~ntioxidant is an ester of 3,3-bis-(3'-t-butyl-4'-hydroxyphenyl)- butanoic acid of the formula ii .4 2. UIV adsorbers and tight stabilizers 2.1 2 2 1-HydroxymethyL)-benzotriazoLes, such as for r~. CH 3 0 11 CH 2 C 0- t-C 4 H- 9 where R4 is a Cl-C 12 -alkyl radical or a C 1 -012-alkylene radical and n is 1 or 2.

6. A polyolefin moulding composition as claimed in claim 5, wherein the triaryl phosphite is tris-(2,4-di't-butyl-phenyl) phosphite and the phenolic antioxidlant is the glycol ester of 3,3-(bis-(3'-t-butyl-4'-hydroxyphenyl)-butanoic acid. QAIED. this 4th day of August, 1992. HOECHST AKTIENGESELLSCHAFT WATERMARK PATENT TRADEMARK ATTORNEYS THE ATRIUM 290 BURWOGjD ROAD HAWTHORN VICTORIA 3122 AUSTRALIA DBM:KJS:BB/M L AU2695688.WPC DOC 16 I 9 9 *94 9 9 S S 9 9* 9 S 99 S 9 9*9* 9 9 5 9 99 9 9t 9