AU621630B2

AU621630B2 - Process for the stabilization of polyolefins

Info

Publication number: AU621630B2
Application number: AU36690/89A
Authority: AU
Inventors: Rolf Mulhaupt; Jean Rody; Mario Slongo
Original assignee: Ciba Geigy AG
Current assignee: BASF Schweiz AG
Priority date: 1988-06-30
Filing date: 1989-06-21
Publication date: 1992-03-19
Anticipated expiration: 2009-06-21
Also published as: CA1340912C; JPH0253807A; EP0350444A1; DD297832A5; KR910000880A; CN1039605A; ZA894936B; BR8903236A; MX169511B; AU3669089A

Description

ik I -1 1 1, 1 Cur Ref: 280340

AUSTRALIA

Patents Act COMPLETE SPECIFICATION

(ORIGINAL)

FORM B<L2 630 Application Number: Lodged: Complete Specification Lodged: r Accepted: a Published: ft 0 Priority: I Related Art: t ft( #0 t 0SS 0 S Applicant(s): Ciba-Gigy AG Klybeckstrasse 141 4002 BASLE

SWITZERLAND

ARTHUR S. CAVE CO.

Patent Trade Mark Attovnerys Level 10, 10 Barrack Straet SYDNEY NSW 2000 Address for Service: Complete specification for the invention entitled "Process for the stabilizat.on of polyolefins".

Thk following statement is a full description of this invention, icluding the best mjthod of performing it known to met- -1-I 5020 JA Process for the stabilization of polyolefins The invention relates to a process for the stabilization or polyolefins and olefin copolymers by the addition of certain stabilizers to the polymerization, the polymerization occurring by a certain process. The invention also relates to the olefin polymers stabilized in this way.

The low pressure polymerization of olefins using organometallic ccmplex catalysts (for example Ziegler-Natta catalysts) normally leads to a fine polymer powder, which has to be granulated in an extruder before the S shaping processing. Stabilizers and other additives are added during this granulation.

Success has recently been achieved in preparing spherically granular S polymers which no longer have to be granulated, but can be directly t ti S" t processed, by the use of solid supported catalysts. Spherical magnesium halides of a certain particle size, as, for example, described in US-A 4,111,835 have in particular proved suitable as supports for these S" solid catalysts. The anhydrous magnesium halide forms insoluble complexes

I

with TiC14 and electron donors, which are then activated with aluminium S alkyls. The stereospecificity and activity are enhanced by the co-use of electron donors, for example carboxylic acid esters or compounds with Si-O-C bonds, described for example in EP-A 45 977.

S Furthermore it has recently been found (EP-A 192 987) that in this kind ,of olefin polymerization, stabilizers of the sterically hindered piperidine type can be added to the polymerization without the polymerization process thereby being impaired.

In this case neither the polymerization yield nor the quality of the polymer are reduced and a stabilizatipn against thermal, oxidative and photochemical ageing is achieved which is at least equal to the effect in i I 2 the case of subsequent edition of a stabilizer of this type to the finished polymer. The advantage is the saving of an operative procedure, namely mixing and granulation.

This stabilization process is described in EP-A, 192 987 and a large number of compounds are described there which are suitable as stabilizers for this process, including also those sterically hindered piperidine derivatives which contain a s-triazine group in their molecule.

In further work in this area it has been found that certain piperidine derivatives which contain at least one s-triazine group in their molecule are particularly suitable for the stabilization of olefins by addition to the polymerization.

c r

S

C a S. t In detail, the invention relates to a process for the stabilization of polyolefins and olefin copolymers, which are prepared by low pressure polymerization on a solid catalyst, which is prepared by the reaction of an aluminium alkyl with a solid product of a magnesium dihalide in active form and a titanium compound, the stabilization being carried out by the addition of a sterically hindered piperidine derivative to the polymerization, wherein a piperidine derivative of the formula I is used, a.

St *4 Si l~i~ ~ir i) in which n is 1-4, R I is C 1 -C4alkyl, allyl, benzyl or acetyl, and is also hydrogen in the case of n 2, R 2 is Ci-Cisalkyl, Os-C12cycloalky C phlkyl,C2penylakyl, C3-Clzalkyl interrupted by or or is a group of the formula II, R' -C CRN (I)

C,\H

_.ir I -3-

R

3 is a group -OR 5

-SR

5 or -N /R6 RI has-one of the meanings given for R3 when n 1, is one of the groups -X-R 8 113 -Nf i-0-o -0or in which q is 2-6, when n 2, is one of the groups -N-k(R -C)H2 3-N or -0CHCH 6 3 6CH2CHZQ- SO CH 2 CH 2

CH

2

O-

when n 3, and is a group c* -N(RG )CH2CH2,--CHC2--CHCH-N(P, or -N(R )-(C11 2 3

(CH

2 (CHZ)3-N(R6)- when n 4,

R

5 is Cl-Ciealkylt C 3

-C

1 Zalkenyl, Cs-Clzcycloakyl, C 7 -Clzphenylalkyl, phenyl or phenyl substituted by CI-C4alkyL, Cl-Ctalkoxy or halogen, R 6 and R 7 are independently of one another hydrogen, CI'Ci$41kyl, Cs-C12cycloa),kyl, C7-Cl2phenylalkyl or a group of the formula II, or R 6 and R 7 are together C4-Cioa1,ylene or CS-Coxa- or azaalkylene, RI is C2zC 1 2 alkylene, C4-Cizalkyleoee interupted by or Cs-Ci,2cycLOalkylene or phenylene, R 9 is hydrogen or methyl, X and Y are independently of one another or m is 2 or 3 and p is 2-10.

The radical R' as C 1 -C4 can, for example, be methyl, ethyl, propyl or butyl and preferably RI is miethyl.

-4- R1, R 5 R' and R 7 as Cl-Claalkyl may be an unbranched or branched alkyl.

Examples thereof are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, sec-pentyl, n-hexyl, 2-ethylbutyl, n-octyl, 2-ethyihexyl, n-decyl, isodecyl, n-dodecyl, 2,2,4,4-tetramethylbutyl, n-tetradecyl, n-hexadecyl or n-octadecyl. RI as al~kyl interrupted by 0 or

N(R

6 may, for example, be 2-methoxyethyl, 2-ethoxyethyl, 2-butoxyethyl, 3-methoxypropyl, 2 -dime thylamino ethyl or 3-diethylaminopropyl.

R

2 R R 6 and IR as CS-Cizcycloalkyl may, for example, be cyclopentyl, cyclohexyl, cyclooctyl or cyclododecyl. A radical of this type is preferably cyclohexyl.

R

2

R

5

R

6 and R 7 as C 7 -Cl 2 phenylalkyl may, for example, be benzyl, 2-phenylethyl, 1-phenylethyl or c,c-dimethylbenzyl. A radical of this *type is preferably benzyl.

R5 as C 3 -Cl 2 alkenyl may, for example, be allyl, methqllyl, but-2- S enyli but-3-enyl, hex-2-enyl, hex-5--enyl, oct-7-enyl or dec-9-enyl.

Compounds with unsaturated substituents of this type p~an copolymerize in o*the react~ n medium.

R

5 as phenyl substituted with alkyl, alkoxy or halogen may, for O o:example, be p-tolyl, m-tolyl, 4-tert--butylphenyl, 4-methoxyphenyl, 03-ethoxyphenyl o'r 4"chlorophpnyl.

R

8 as 02-Cl 2 alkylene may be unbranched or branched alkylene. Examples thereof are di-, tri-, tetra-, hexa-, octa-, deca- and do de came thylene, 1,2-propylene or 2,2-dimethyl-1,3-propylene, If the alkylene radical is interrupted, by 0 or N(R6), this may, for example, be 3-oxapenta- .:methylene, 4-oxaheptamethy].ene, 3, 6-dioxaoc tamnethylene or 3-aza- or 3-methylazapentamethylene.

R

8 as cycloalkylene may in particular be cyclohexylene.

When R' and R' together are alkylene, oxa- or azaalkylene, they form, together with the N atom to which they are bonded, a heterocyclic ring, for example a pyrrolidine, piperidine, hexamethyleneimino, morpholine or piperazine ring. These rings may be alkyl-substituted.

Those compounds of the formula I are preferably used in which n is 1-4, R' is Ci-Cz 4 alkyl, and is also hydrogen in the case of n 2, R 2 is CI-Cizalkyl, cyclohexyl, benzyl or a group of the formula II, R 3 is a group -OR 5 or -N(R 6

)(R

7 R4 has one of the meanings given for

R

3 when n 1, is a group -X-R 8 or -NI >C1 2 Cli2-N(R' when n 2, is a group -N(R 6

)-(CH

2 M_ _(CH 2 M_ w~hen n and is a group -N(,R 6 )-HC2 -HCZ--HC or

S-N(R

6

)-CH

2

CH

2

CH

2 -4-(CH2) p- -C1 2

C

2 CHz-N(R 6 when n =4, 5 is Cl-Cizalkyl, cyclohexyl, benzyl, phenyl or tolyl, R 6 is hydrogen, ,4 Ci-Cazalkyl, cyclohexyl, benzyl or a group of the formula II, TV is *44CI-Gazalkyl, cyclohexyl or a group of the formula II or R6 and R 7 are 4 together tetramethylene, pentamethylene or 3-oxapentamethylene, R8 is C2-Clzalkylene, cyclohexylene or 'henylene, X and Y are or -N(R 6 m is 2 or 3 and p is 2-6.

4 Preferably, R1 is methyl and R 2 is CI-Cealkyl or a group of the formula II. Preferably R 3 is a group -N(RB)(RI) When n I in *formula I, R4 is preferably a group -N(R (R 7 When n 2, X and Y are preferably a group and RI is preferably CZ-Csalkylene.

When n =3 or 4, RB is preferably hydrogen or Cl-Ci~alkyl, particularly methyl.

The compounds of the formula I are known compounds or can be prepare4d by analogy thereto. Compounds of this type are described for example in 'Us-A 3,925,376, US-A 4,108,829, EP-A 107 615, DE-A 3 727 977, DE-A 3 809 628, Er-A 292 437, EP-A 299 925.

Examples of piperidine compounds which may be used according to the invention are the compounds of the following formulae: -6- 19 01131K kli 9 X 2I CHN3C-N \0 9 4-11N 4, CH3 >-C13 t 1 i C 8 11 4 44 4 *1 NJ1 ,.N>-Cfl3 7- 8. R- R13 (022 A H

I

I qln(Ci 3 2

,N\

N R2 8 7/ V 2 11 >t 1 N

N

R2-.

8- AH3 R3= A4Rz

A

y2H R /2~-R A3 y 16. R i 4 1 19 4 1 16 Ri -(fl)-y-CC

H

I2- -(CHiz, 3

_R

\R ILI\N 'R

A

1 R el "OR~ I Y8/ v/) R"3 3 R/3 "N R 3A 3 -9- 19- CH3- 9/

C~

3 ~V\.i4 H9 /NN CH/ -N>-CH 3 1kHC 8 Hl7.

21. CU3-NI Ei N-CH1 3 21, H~N(1.RIgk \s N-CH 3 \/i *44. 22 W A4 A I 4 1 24, -Rla

A

t 0 1.4I** t H- 4ll I Q 4'1

A

1 BLN i> R .4 4 WiNtx R l'R 4e

N

/1 I\

R

5 -I-cU 2 CN\ X- 4444

NH

'4 4r *d In: the fomulae 1-:26, is a 1 ,2,2,6,6-pentamethylpptdine raidical.

4.44 4 4o The polymerization ctal~ysts used ar~e solid catalysts. They comprise an anhydrous mognesium dihalicle in aqtivo form and a titanium compound, A magnesium dihalido in actiVq form is to be umur~stood As meaning a magnesium dihalide Jin whose X~-ray spectrum the I tli the stronsest reflection is broadened in compai*son with the 0oz'esponding l~ine in the spectrom of the inactive wagnesiur halide.

The maneSoi'm halide used is prefEerably magnosiom diohlordo or magnesium bromide, Preforablys spherical maonosiom chloride is used The titanium.

compound preferably contains At least o titaniur-halogen bond, And titanium tetrachlorid is particularly preferably used, 11 The titanium compound can be used in combination with an electron donor, for example a carboxylic acid ester, as described in EP-A 45.977.

After the reaction of the magnesium halide component with the titanium compound and, if desired, with the electron donor, the excess of titanium compound and the excess of electron donor are expediently washed out with an inert solvent for example with hexane or heptane.

The catalyst prepared in this way is activated by reaction with an aluminiumalkyl, which is preferably used as a solution in an alkane.

Examples of suitable aluminium alkyls are Al(CzH 5 3 or Al(C4H9) 3 Here, an electron donor can be added as coactivator, for example an organosilicon compound which contains at least one Si-O-C bond, as described for example in EP-A 45 977. Example.. of silicon compounds of this type are phenyltriethoxysilane, phenyltri ethoxysilano, diphenyldimethoxysilane methyltriethoxysilane, dimethyldiethoxysilane or ethyltrimethoxysilane.

1 o o.

99 9 4,j The polymerization with these catalysts can be carried out in the liquid 0 *0 Sor gaseous phase, It is preferable to operate in the liquid phase, for SD" example in alkanes or in the liquid monomer.

The stabilizer (piperidine compound) can be added at the beginning of the polymerization, during the polymerization.r ate-- th- end- -thc p- .er- Saation. It is preferably added during the polymerization.

Vigorous stirring is expediently used to ensure as homogeneous a distribution as possible of the catalyst and of the stabilizer in the polymerization medium, 9 9 The quantity of piperidine stabilizer added is governed by the desired degree of stabilization. Generally 0.01 to 5 by weight, particularly 0.05 to 1 by weight, relative to the polymer are added.

-12 Ap~irt from the piperidine stabilizer, other stabilizers may also be added during polymerization. Phospho~rus'III) esters aire particularly suitable as other .ztabiJl,zers. These may be phosphites, phosphonites or phosphinites. They may contain one or more phosphorus ester groups. Preferably A trio rg anopho sphi te is added. Examples of phosphorus(III) esters of this type are: tripheny. phosphite, decyl diphenyl phosphite, phenyl didecyl phosphite, tris.(nonylphenyl) phosphite, trilauryl phosphite, trioctaf*'-cyl phosphite distearyl pentaerythritol diphosphite, tris(2, 4 di-tert-'butylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, tristearyl sorbitol triphosphite, te traki s(2, 4-di- ter t-bu tylphenyl N-4, 4'-biphenylene diphosphonite, bis(2,6-di-tert-butyl-4.-methylphenyl) pentaerythritol diphosphite.

Alternatively or in addition to the phosphQrus-(III) esters, other stabilizers or additives which do not impair the polymerization. process may also be added, for example antioxidants of the sterically hindered phenol type.

*The following compounds are examples of antioxidants of this type: Alkyl'-substituted monophenols,, for example 2, 6-di-tqrt-butyl-4-methylphenol, 2-tert-butyl-4,6-diiethylphenol, 2 ,6-di-tert-butyl-4-ethylphenol, t2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl-4-isobutylphenol, t ?,6-dicyclopentyl-4-niethylphenol, 2 -(ct-me thylcycl ohexyl) -4 6 -dime tbyl- I phenol, 2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol, 1. 2,6,,di-tert-butyl-4-methoxymethylphenoI and 2,6-dinonyJ,-4-methylphenol.

Alkyl-substituted hydrociuinones, for example 2,6-di-tert-butyl--4-methoxy- Sphenol, 2,5-di-tert-butyihydroquinone, a,5-di-tert-amylhydroquinone and 2,6-diphenyl-4-octadeoyloxyphdnol.

Iydroxyl-substituted thiodiphenyl ethers, for examplte 2,2'-thio-bis(6ter t-bu tyli-4-me thylphenol) 202'-thio-bis(4-octylphanol), 4,4'-thio-bis- (6-tert-butyl-3-.methylphenol) and 4,4'-thiio-bis(S-ter~'-butyl1-2-methylphenol).

11 Alkylidene-bisphenols, for example 2,2'-methylene-bia(E.-tort-buty'--4methylphenol), 2,2 '-methylene-bis(6-tert-buty!l-4-ethj-,lhenol), 2,2methylene-bis (4--methyl-6-(ci-methylcyclohexyl) phenol I, 2,2 '-methylenebis( 4-me thyl-6-cyclohexylpheno 2,2'-me thylene-bis( 6-nonyi.4-methylphenol), 2,2 '-inethylene-bis(,4,6-di-tert-butylphenol), 2,2'-ethylidene-, bis(4,6-di-tert-butylpbenol), 2,2'-ethylidene--bis(6-tert-butyl-4-isobutylyphenolt), 22 mtyeebs6(Lr~hlezl--oypeo] 2,2 '-methylene-bis[6-(c,a-dimethylbenzyl)-4-nonylphenolI, 4,4'-methyloinebis(2,6-di-tert-butylphenol), 4, 4'-me thylene-bis tert-butyl-2-ie thy 1phenol), 1, I -bi ter t-bu tyl-4-hydroxy-2.-me thyphenyl) butane, 2,6-his- (3-tert-butyl-5-methyl--hydroxybeniyl)-4-methylphenoll,1, -ri( tert-butyl-4-hydroxy-2-me, hylphenyl)butane, 1 ,1-bis(5-tert-butyl-4hydroxy-2-ne thylph enyl) 3n-do de cylne r cap tobu tane ethylene glycol bis f3,3-bis(3'-'tert-butyl-4'-hydroxyphenyl) butyra.tel, bis(3-tert-buillyl-4- 4 00I hydroxy- 5-me thy lpbenyl) dicyclopen tadiene and bisl2-(3'-tert-butyl-2'- *NO# hydroxy-5-methylbenzyl)--6-tert-butyl-4-metliylphenylI terephthalate.,

I,

4 44 4 .4 9, 9 9, 44 9 .94' 9, 99 44 4 o A -9 4~ 44 9, 9 9 44 4 9 4 49 44 49 0 4444 4 4 4 9A 4 9 44 4 44 Benzyl compounds, for example 1,3,5-tris-(,5-di- tert-butyl-4-hydIroxybenzyl)-2,4, 6-trimethylbenzene, bis(3,5-di-tert-butyl-4-hydro, :,zl) sulfide, isooctyl. 3, 5-di-tert-butyl-4-hydroxybenzylmerqaptoa f bis(4-tert-buty-3-hydroxy-2 ,6-dimethylbenzyl)dithiql, tereplhali 1 i-tris(3,5-dU,-tert-butyl-4-hydroxybenzy1) isocyanurate, 1, tert- butylt-3-hydroxy-2 ,6-dimethylbenzyl isoayanurate, dio, 3,5-di-tert-butyl-4-yroxybenzylphosphona.Ze, 'he Ca salt of monoethyl 31,5-'di-tert-buty,-4-hydoxybenzylphosphoriate atid 1 ,3,S-tris(3,j5-dcycJloboxyl-4-hydroxybenzyl) isocyanurate.

Acylaminophenol s, for example 4-hydroxylauranilide, 4-hydroxcystearanilide, 2,4-bis(octylmercapto)-6-(3,5-di-tet-bity'- 4 hydroxyanilino)-s-riaine and octyl N-(3,5-di-tet-butyl-4-hydroxyphenyl)carbarnate.

I

14 Esters of R-(3,5-di-tert-butyl-4-ydroyphenyl)-propionic acid with monohydric or polyhydric alcohols, for example with methanol, octadecanol, 1, 6-hexanediol, neopentyl glycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pentaerythritol, tri(hydroxyethyl) isocyanurate or N4li'-bis(hydroxyethyl)oxalamide.

Esters of 5-tert-butyl-4-hydroxy-3-methylplen y])-propionic acid with monohydric or polyhydric alcohols, for example with ilethanol, octadecanol, 1 ,6-hexanedio,, neopentyl gl~ycol, thiodiethylene glycol, diethylene glycol, triethylene glycol, pen1taerythritol, tris(hydroxy) eLtyl isocyanurate or N,N'-bis(hydroxyethyl)oxgiamide.

Esters of B-(3,5-dicyclohexyl-4-hydroxyphonyl)-propionic acid with monohydric or polyhydric alcohols, for example wi,,h methanol, octadecanol, 1,6-hexanediol, neopenty. glycol, thLodiethylene glcyol, diethylene glycol, triethylene glycol, pentaerythritol, tris(hydroxy) ethyl isocyanurate or N,N'-bis(hydroxvyethyl)oxalamide.

Amides of_1-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionic acid, for example N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropi'onyl)hexamethylenediamine, N ,N -bis( 3,5-di-tert-buty1--4-hydroxyphenylpropionil)t rime thylenediamine and N,N'-bis(3,5-di-tert-butYl-4-hydroxyphenylpropionyl)hydrazine.

The amount of phosphor'Us(III) estev or other stabilizers is governed by the amount of piperidine compound added. Generall~y 0.01 to 1 by weight, *Qparticularly 0.05 to 0.5 by weight, is used relative to the polymer.

The process according to the invention relates tt, the addition of stabilizers to the polymerization or copolymerizaton of olefins. The olefins may be ethylene or ca-olefins. Examples of an a-oJlef in are propylene, 1-butenej I-pentene, 3-me thyl-1 tone, 4-methyl-I-pentr'ne or For copolymer~ization, mixtures of olefins witb one another can be used, or mixtures of olefins wit~h other ethylenically 15 unsaturated compounds, for example with vinyl acetate, vinyl chloride or alkyl acrylates. The process is of particular interest for the polymerization of propylene.

The invention also relates to the polymers or copolymers of olefins which have been stabilized according to the invention, particularly a polypropylene stabilized in this way.

The following examples illustrate the process in more detail without limiting it to the scope of the examples. Parts and percentages therein are by weight, unless stated otherwise.

Example 1: Polymer'zation of propylene The polymerization is carried out in a thermostatically controlled 4-litre stainless steel autoclave, equipped with a stirrer, which is dried before the beginning of the polymerization by purging for one hour with propylene gas at 70°C. The preparation of the solid catalyst component made from spherical MgClz and TiCl1 is carried out as described in Example 1 of US-A 4,111,835. It contains 2.9 of Ti and 19 of Mg.

mg of this catalyst are suspended in 25 ml of n-hexane and a mixture of 685 mg of triethylaluminium, 80 mg of phenyltriethoxysilane and 200 ml of hexane is added. This catalyst suspension is transferred under propylene gas to the autoclave. After closing the autoclave 1.25 1 of highly pure hydrogen are injected and finally 1.2 kg of liquid propylene are added under pressure. The contents are heated to 700C with stirring (500 rpm) and kept at this temperature for 2 hours. Then the excess of c propylene is released and the polymer obtained is treated with steam at 100 0 C for 10 minutes and subsequently dried at 50°C for 8 hours. The polymer consists of spherical particles. The following investigations of the polymer are carried out.

The catalyst activity (g of polymer/g of catalyst) is calculated from the Mg; content determined by atomic absorption and from the polymer yield.

I

16 The isotacticity is determined as the percentage proportion of the polymer which is insoluble in hot xylene. For this purpose the polymer is dissolved in hot xylene and after cooling the insoluble portion is filtered off and dried to constant weight.

The polymer morphology is qualitatively assessed visually, in order to determine wihether agglomerations have occurred.

The colour of the polymer is characterized by the Yellowness Index in accordance with ASTM D 1925-70.

As an indirect measure of the molecular weight, the intrinsic viscosity in tetrachloroethylene at 135°C is determined as well as the melt flow index in accordance with ASTM D 1238 at 230°C/2160 g.

.41

I

polo 4 04 4 W 0 4 4) ea *4 a 4.

«<4 4* 44 4 4* 4 4 The stability to oxidative degradation is determined from the time which elapses until there is a discernible emb_-c.lement of the polymer during oven ageing at elevated temperature. This cest is carried out on sheets, which are produced by press moulding at 220°C.

The following values resulted for the unstabilized polypropylene described above: Catalyst activity Isotacticity Intrinsic viscosity Morphology Melt flow index Yellowness Index Oven ageing of sheets 45.5 kg 97.0% 1.8 dl/g spherical 15 g/10 min at 135C. 0.75 h at 150°C: 0.50 h l -uL r^rrrrr.

17 Example 2: Stabilization The procedure described in Example 1 is repeated. About 10 minutes after the beginning of the polymerization a solution of 0.45 g of the stabilizer (piperidine compound) given in Table 1 in 50 ml of hexane is added to the autoclave. Polymerization, working-up and characterization of the polymer are carried out as in Example 1. The characteristic values obtained are listed in Table 1.

Table 1 49 w 91 4 9*

,J

4Q Stabiliser (Comp. no.) 1 2 4 8 9 10 11 Catalyst activity (kg/g) 45,5 43 41,8 40 43 45,5 45,5 Isotacticity 97.1 97.1 96.8 96.9 97.0 97.1 97.2 Intrinsic viscosity (dl/g) 1.9 1.8 2.0 1.8 1.84 1.56 1.55 Morphology Melt flow index (g/10 min) 6.6 9.0 6.0 6.3 13.3 15.3 14.2 Yellowness Index 2.2 1.9 2.4 2.5 2.2 2.4 2.3 Oven ageing at 135°C >700 >700 700 >700 860 900 860 at 150°C 180 325 370 320 250 55 240 as in Example 1 Table 1 (continued) Stabiliser (Comp. no.) 13 14 15 17 18 Catalyst activity (kg/g) 45.5 45.5 40.9 45.5 45.5 Isotacticity 97.0 96.9 97.0 97.0 97.0 Intrinsic viscosity (dl/g) 1.55 1.73 1.54 1.90 1.75 Morphology Melt flow index (g/10 min) 16.7 13.8 14.2 8.1 12.6 Yellowness Index 2.8 2.6 4.4 2.8 2.4 Oven ageing at 1350C 410 458 220 700 860 at 150 0 C 25 250 70 370 119 as in Example 1 :I ;ai I t 18 Table 1 (continued) Stabiliser (Comp. no.) 19 20 21 22 23 124 Catalyst activity (kg/g) 43. 2 45. 5 45. 5 43 43.2 45.5 44.1 Isotacticity ()97 97 97 97 97 92.2 97 Morphology MHelt flow index (g/10 min) 5.8 5.4 7.3 8.4 6.2 14.2 2.8 Yellowness index 3.2 3.4 3.3 3.4 3.2 4.0 3.7 Oven ageing at 150'C 288 216 408 400 410 240 400 Example 3: The procedure described in Example 1 is repeated. One h-our after the beginning of the polymerization a solution of 0.21 g of compound No. 3 in 50 ml of hexane is added to the polymerization mixture.

Working-up and -characterization are carried out as in Example 1.

The following values were obtained: a ~a a o ~a

O~

o a~ o a a a, a, a p a a a aa a, 9* a. a a, qa a a a.

A,

p Catalyst activity Isotacticity Intrinsic viscosity Morphology Melt flow index Yellowness Index Oven ageing of sheets 45. 5 kg 97,0% 1.9 dlfg as in '.xample 1 7.4 (g/10 min) at 13500: >100 h at 150'C: 144 h a a a. a.

a a.

Claims

1. A process for the stabilization of poJlyolefins and olefin copolymers, which are prepared by low pressure polymerization on a solid catalyst, which is prepared by the reaction of an aluminium al~kyl with a solid pioduct of a magnesium dihalide in active form and a titanium compound, the stabilization being carried out by the addition of a sterically hindered piperidine derivative to the reaction mixture before or during polymerization, wherein a piperidine derivative of the formula I is used, C 3 CH 3 Cfi\CH 3 L in in which n is 1-4, RI is CI-C~alkyl, allyl, benzyl or acetyl, and Is S also hydrogen in the case of n R 2 is Cl-Claalkyl, Cs-Cl2cyclo- alkyl, C7-Cl2phenylalkyl, C3-CI2alkyl interrupted by or -N(R1 or is a group of the formula II, C 3 /CH3 R1 (n) o" cw3 R 3 is a group -0R5 -SR$ or '\R7 R 4 has one of the meanings given for R 3 when n 1, is one of the groups -X-R 8 Y-, 0- K or -I -CH 2) in which 9 is 2-6, when n 2f is one of the groups IA4/ I -C2 wcH 2 B) 3 -N or -OCH 2 CH 2 R 8 CH 2 CH2o- when n and is a group -N(R 5 )-CH 2 CHi 2 -A-CH2CH2--1C1H 2 CH 2 or 2 3 -A-(CH 2 p-k(H)3NR) when n 4, R 5 is Cl-CBalkyl, C 3 -G 1 2 alkenyl, Cs-C 1 2 tycloakyl, Cr-Clapheny2,alkyl, phenyl or phenyl substituted by Cl-Ci~alkyl, CI-C~.alkoxy or halogen, RI and R 7 are independently of one another hydrogen; Ci-C,8alkyl, CS-C12- cycjloalkyl, C 7 "Clzphenylalkyl. or a group of the formula II, or R 6 and R 7 are together 04-Cioalkylene ot CS-C7oxa- or azaal1kylene, RI is C 2 -C12- al1kylene, Ci-Cazalkylene interrupted by or -N(R 6 C 5 -C1 2 CYClo- .alkylene or phenylene, R 9 is hydrogen or methyl, X and Y are indepen- 4 dently of one another or -N(R 6 m is 2 or 3 and p is 2-10.

2. The process according to claim 1 wherein a piperidine derivative of the formula I is used, in which n is 1-4, R! isC-C4alkyl, and is also *#JtlA.SJ 5 *S 14 tO0C 'JA U )2 4* .0 Jj U. 5, tJ 4I4~O *0*4 9 9, 4a 4 aa 4 9 4* @4 9 S 4aa4 U 4 4* 4 44 4

4. a a 4 49 group of the .ioruiula II', R 3 is a grouip -ORS or has one of the meanings, given for R 3 whem n is a group or -<>-CH2CH2-N(R6)- when n is a group -NR -C1)m -CZmNR) when n =3 and is a group -N(R~6 )-Cfl 2 C1Iz-g-C zH--t2Cl-() or -N(R6)-CHl2CH 2 CHZ-A(C"iz) p-kC1C2C2Re) when n -4, R5 is CI-Ca2alkylo cyclohexyl, benZyl, pbenyl. or tolyl, R' 6 is hydrogen, Cl-Cl2alkyl, rqyclobexcyl, bemzyl or a group of the formula II, R 7 is CI-C12alkyJ, cqyclohexyl or a group of the formula 11 ov 10 and R1 are together tetramethyleme, pentamethylene or 3-oxapen tame thylene R' is C2-Clzalkylene, cyclohexylene or phenylone, X and Y are or m is 2 or 3 and p is 2-6. <4 21 3. The process according to claim 1 wherein in formula I, R I is methyl. 4. The process according Ci-Csalkyl or a group of The p-oce,is according -N(R 6 (R 7

6. The process according is a group -N(R 6 )(R 7 to claim 1 wherein in the formula II. formula I, R 2 is to claim 1 wherein in formula I, R 3 is a group to claim 1 wherein in formula I, n 1 and R 4

7. The process according to claim 1 wherein in formula I, n 2, X and Y are a group -N(R 6 and R 8 is Cz-Csalkylene.

8. The process according to clainm I wherein in formula I, n 2 and RI *4 94 a 04 4 4 4 9 4 0 44* as 4' *44 4 4 a. is a group -NH-CH2C 2

9. The process according to claim 1 wherein in R 6 is hydrogen or Ci-Cialkyl. formula I, n= 3 or 4 and The process according to claim I wherein the catalyst from spherical magnesium chloride. is prepared

11. The process according to claim 1 wherein titanium tetrachloride is used as titanium compound in the preparation of the catalyst.

12. The process the addition of

13. The process having at least according to claim 1 wherein the catalyst is activated by an electron donor. according to claim 12 wherein an or nosilkco compound one Si-O-C bond is used as electro .,nor. 22 14, The process according to claim 1 wherein, apart from the sterically hindered piperidin compound, a phosphorus(III) ester is added to the polymerization. The process according to claim 14 wherein a triorganophosphite is added, 16, The process according to either of claims 1 or 14, wherein an anti- oxidant of the sterically hindered phenol type is additionally added to the polymerization, 17, The process according to qlai 1 wherein the process is used for the polymerization of propylene

18. A polymer stabilized by the process of claim 1. a ts<' g4th I

19. A polypropylene stabilized by the process of claim 1. ,4 S 20, A process a4cording to Claim L, or a polymer According to Is 1 Claim 18, substantially as herein desaribed, with reference to Pc 6 a ny one of the foQregoing examples thereof, *4 I Dated the 20Wt .M or ue 1989 CIBA-GEIGY A 4 G. a Oy Its Patent Attorneys ARTHUR S. CAVE CO.