DE2756612A1 - STERICALLY DISABLED PHENOLHYDRAZONE AND THEREFORE STABILIZED MASS - Google Patents

Description

CIBA-GEIGY AG, Basel, Switzerland V ^ I ^ J ^ A ** "" ¹ VJ1— | \ JJ

Case 3-10904 / GC 805 / +
GERMANY

STERICALLY DISABLED PHENOLHYDRAZONE AND THEREFORE STABILIZED MASS

The present invention relates to a novel class of hindered phenol hydrazone compounds which are useful as stabilizers for polymers. These hydrazones correspond to the formula

HO

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where R, for hydrogen or straight-chain or branched alkyl with 1 to 8 carbon atoms, R ₂ for straight-chain or branched alkyl with 1 to 8 carbon atoms, η for an integer from 1 to 5 and preferably 2, R ¹ for hydrogen or alkyl with 1 up to 8 carbon atoms and R, for alkyl with 1 to 18 carbon atoms, for phenyl optionally substituted by 1 to 3 alkyl groups with 1 to 4 carbon atoms or for an interrupted alkyl, which under the formulas

Ii

ft TT C! f * TT κ ιν \ / 3 fi TT Q ft TT f \ r ^ 1J

~ ° p 2P t ^H 2t + l " ¹ ^" ^u p ^H 2p ~ ^£> ~ ^o t ^H 2t " ^u " ^t ' ^K 4 is selected, where ρ and t are independently integers from 1 to 18 and R ^ for an alkyl group with up to 17 carbon atoms or an olefinic group of the formula

- (CH ^) - CH = CH (CH.,),. CH-, in which ζ and y are independent of a- t- ζ c. y j

other integers from 1 to 12, or R, the group

R-

OR ¹ HI

CH _n -CN ¹ HU = CTn 2n

represents where T is a direct bond, alkylene with 1 to

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6 carbon atoms or alkylene of the formula ^ CH ₂ -) X- (C Ji, _a -) interrupted by sulfur or oxygen, where X is sulfur or oxygen and a is an integer from 1 to 6.

As alkyl, R ₁ , R ₂ and R 'are, independently of one another, for example straight-chain or branched alkyl with 1-8 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, η-butyl, sec-butyl, tert-butyl, 2 -Aethylbutyl and n-octyl and tert-octyl. For R-. and Rp, α-branched alkyl radicals having 3-8 carbon atoms are preferred, and tert-butyl is particularly preferred. The group R · is preferably hydrogen or alkyl having 1 to 4 carbon atoms.

In the definition of R, alkyl, which can be straight-chain or branched, or phenyl is preferred, and if it is an interrupted alkyl, the integer ρ preferably represents 2 to 6 and in particular 2 to 4 and t represents 8 to 18. The Whole numbers ζ and y are preferably 4 to 12. If R is a sterically hindered phenolic alkanoate hydrazone group of the above formula, T preferably represents a direct bond, alkylene with 1 to 4 carbon atoms or various phenylene isomers such as 1,3-, 1,4- or 1,2-phenylene. If T is an interrupted alkylene, X is preferably sulfur and a is 1 or 2, in particular 1.

The novel sterically hindered phenolhydrazone compounds according to the invention are produced by a method in which it is the implementation of a sterically hindered phenol hydrazine with an optionally substituted alkyl

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aldehyde or ketone, the substituent being a thioalkyl or thioalkylene ester group. The sterically hindered phenol hydrazines and their preparation are in US U.S. Patent 3,660,438, which is hereby expressly pointed out will. The classes of aldehydes and ketones used in the preparation of the hydrazones are known and are well known illustrates the following formulas:

a) R ₅ CH (R) CH ₂ CH

b) R ₅ SCH (R) CH ₂ CH ₀

c) R ^ CO- (CH ₂ ) _n -S-CH (R) CH ₂ CH

d) R ¹ CR ₃

where R ^ has the meaning given above and R _{5 represents} alkyl with 1-12 carbon atoms or aryl, in particular phenyl and alkyl-substituted phenyl, and R represents methyl or hydrogen. The reaction is generally carried out in an inert solvent such as an alcohol at a temperature of 25 ° to 100 ° C. and preferably 40 ° -70 ° C. for about 2 to 5 hours. It is sometimes useful to use a catalytic amount of a Lewis acid such as AlCl, MgBr ₂ or ZnCl ₂ and in particular BF, or acids such as hydrochloric acid, sulfuric acid or phosphoric acid, in order to accelerate the reaction. This is especially true when one of the reactants used is a less reactive ketone. The aldehydes (a) are generally commercially available and can also be prepared by oxidation of the corresponding alcohols, reduction of the corresponding acids or rearrangement of terminal epoxides. The aldehydes (b) can best by the base-catalyzed

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Attachment of a mercaptan to an α, ß-unsaturated aldehyde getting produced. The aldehydes (c) can be prepared by the same method as the aldehydes (b), except that one Mercaptans of the formula RcC-O- (CHp) -SH are used. The ketones (d) are generally commercially available or would be by oxidation the corresponding secondary alcohols or by condensation of two identical or different acid molecules can be prepared in the presence of a base.

The compounds of the invention are useful as Stabilizers for various polymers, in particular olefin homopolymers and copolymers and diene rubbers. Explanatory Examples of olefin polymers are:

1. Polymers derived from mono- or diolefins, for example optionally crosslinked polyethylene, polypropylene, polyisobutylene, polymethylbutene-1, polymethylpentene-1, polyisoprene and polybutadiene.

2. Mixtures of the homopolymers listed under 1), for example mixtures of polypropylene and polyethylene, polypropylene and polybutene-1 as well as polypropylene and polyisobutylene.

3. Copolymers of the monomers that are the basis for the below

1) represent listed homopolymers, for example ethylene /. Propylene copolymers, propylene / butene-1 copolymers, propylene / isobutylene copolymers, ethylene / butene-1 copolymers and terpolymers of ethylene and propylene with a diene, for example hexadiene, dicyclopentadiene or ethylidenenorbornene, or with acrylates, methacrylates, vinyl acetate or the like Comonomers copolymerized monoolefins.

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Substrates by the compounds according to the invention are particularly well stabilized are rubbers containing diene such as polybutadiene and butadiene copolymers such as SBR (styrene / butadiene rubber), ABS (acrylonitrile / butadiene / styrene copolymer, thermoplastic SBR (styrene / butadiene / styrene block copolymers), Methacrylate / acrylonitrile / butadiene / styrene copolymers and barrier resins (ABS copolymers with a high acrylonitrile content) and various ethylene / propylene / diene rubbers. The above Stabilizers are used in amounts of 0.01 to 5% by weight based on the butadiene rubber. Particularly preferred is the stabilizer concentration was 0.05 to 2% by weight Rubber. The addition of further stabilizers and other additives before and / or during production is in the works. strive to pull.

The following examples are for the purpose of illustration of the present invention are given below and are not to be construed as a limitation on the invention.

EXAMPLE 1

Preparation of 3- (3 ", 5" -di-t-butyl-4 ¹ -hydroxyphenyl) -propionyl hydrazide

Methyl 3- (3 ', 5'-di-t-butyl-4 ¹ -hydroxyphenyl) propionate (146 g, 0.5 mol) is dissolved in 500 ml of dry methanol. This solution is treated with hydrazine hydrate (101 g, 2 mol) at room temperature. The mixture is then refluxed for 10 hours. The product crystallizes out on cooling to room temperature. It is isolated by filtration, washed with a little cold methanol and dried. 116.7 g are obtained (80% yield)

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AT

white solid with a melting point of 149-151 ⁰ C.

EXAMPLE 2 Production of n-dodecylthio-3-methylpropanal

In the course of 65 minutes, add crotonaldehyde (72 g, 1.0 mol) (202 g, 1.0 mole) to a stirred solution of n-dodecylmercaptan and triethylamine (2 g), maintaining the temperature at 55-6O ⁰ C is held. After the addition is complete, the reaction mixture obtained in this way is heated to 85 ^° C. for 0.5 hour. Thin-layer analysis (DSC) shows that the reaction is complete, and this intermediate product is used to prepare the product described in Example 3 without further purification.

If acrolein or cinnamaldehyde is used instead of crotonaldehyde in the above reaction, n-dodecylthiopropanal is obtained or n-dodecylthio-3-phenylpropanal.

EXAMPLE 3

Preparation of n-dodecylthio-3-methylpropanal-3- (3 ', 5'-di-t- butyl-4'-hydroxyphenyl) propionyl hydrazone

3- (3 ', 5'-di-tbutyl-4 ^r -hydroxyphenyl) propionyl hydrazide (58.4 g, 0.20 mol) prepared in Example 1 is heated in 2-propanol (500 ml) with stirring 60 ⁰ C. added dropwise in the course of 15 minutes example 2 made of n-dodecylthio-3-methyl-propanal (54.5 g, 0.20 mol). The resulting solution is stirred under reflux for 3.5 hours. The solvent is then driven off at 70 ° C./20 torr. This gives 112 g of residue which solidifies to a white solid with a melting point of 53-7 ° C. The raw

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ΛΑ

is product from a mixture of ethanol (50 ml) to give (750 ml) and Yiasser and provides 82 g solid of melting point 69-72 ⁰ C, which shows the following analysis. Calculated for C ₃₃ H ₅₇ N ₂ O ₂ S: C, 72.61; H, 10.52; N, 5.13; S, 5.87

Found: C, 72.76; H, 10.97; N, 5.22; S, 5.78

EXAMPLE 4

Production of n-dodecylthiopropanal-3- (3 ^!, 5'-t-butyl-4'-hydroxy phenyl) propionyl hydrazone

Proceed as in example 3 with the difference that n-Dodecylthiopropanal (prepared in the second part of the example 2) is used, the above compound is obtained.

EXAMPLE 5

Production of ethylthio-3-methylpropanal oleate-3 '- (3 ", 5" -di-t- butyl-4 "-hydroxyphenyl) propionyl hydrazone

The solution of 3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionyl hydrazide (13.89 g, 0.0475 mol) in 125 ml of 2-propanol is heated to 60 under nitrogen with stirring ⁰ C and mixed with a solution of ethylthio-3-methylpropanaloleate in the course of about 0.25 hour. After the addition, the resulting mixture is stirred and refluxed for 4 hours. After cooling, the reaction mixture is freed from the solvent and dried, which gives an amber-colored syrup. NMR analysis confirms the formation of the desired product, which gives the following analysis:

Calculated for ^c z _t i ^H 70 ° 4 ^N 2 ^{S: C} » ⁷¹ » ⁶⁷ » ^H » ¹⁰ » ² 7» Ν, 4.08

Found: C, 71.89; H, 9.80; N, 4.74 Aethylthio-3-methylpropanal-

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oleate, ethylthio-3-methylpropanal stearate, ethylthio-3-methylpropanal laurate or use ethylthio ~ 3-methylpropanalacetate, which gives the corresponding products.

EXAMPLE 6

The following connections are made according to the working method prepared according to Example 3 and using the appropriate reactants:

a) n-Tridecylthio-3-methylpropanal-3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone - syrup

b) n-Dodecylal-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionyl hydrazone - Melting point 74-77 ° C

c) N-2-0ctyliden-N'-3- (3 ", 5" -di-t-butyl-4 'hydroxyphenyl) propionyl hydrazone - 83-88 ⁰ C

d) N-α-methylbenzylidene-N'-3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone - 192-196 ° C

e) N-2,6,8-trimethyl-4-nonylidene-N '-3' - (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone - syrup

f) 2,3-Dimethylvaleral-3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone - Melting point 109-113 ° C

g) isovaleral-3- (3 ', 5'-di-t-butyl-4-hydroxyphenyl) -propionylhydrazon - melting point 177-180 ⁰ C.

h) 5-methyl-2-pentylidene-3 '- (3 ", 5" -di-t-butyl-4-hydroxyphenyl) -propionyl-hydrazone - melting point 149-152 ⁰ C.

i) 2-Methylpropylal-3 '- (3 ", 5"-di-t-butyl-4' hydroxyphenyl) propionyl hydrazone - melting point 195-198 ⁰ C.

j) n-Pentylal-3- (3 ^f , 5'-di-t-butyl-4-hydroxyphenyl) propionyl hydrazone - melting point 149-151 ° C

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k) 1,4-phenylene-diformal-bis [3 '- (3 ", 5" -di-t-butyl-4-hydroxyphenyl) -propionyl-hydrazone] melting point 275-280 ° C (decomposition) 1) Aethandial-bis- [3- (3 ', 5'-di-t-butyl-4 ~ hydroxyphenyl) propionyl hydrazone] - Melting point 271-273 ° C

m) 1,3-propanedial-bis [3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone] - Melting point 150 ~ 157 ° C η) 1,3-phenylene-diformal-bis- [3 '- (3 ", 5" -cli-t-butyl-4-hydΓoxyphenyl) -propionyl-hydrazone] - Melting point 253-26l ° C.

The following compounds are also prepared in accordance with the procedure according to Example 3 with the difference that the corresponding starting materials are used: n-Dodecylthio-3-methylpropanal-3 '- (3 ^M , 5 "-di-t-octyl-4" hydroxyphenyl) propionyl hydrazone

n-Octadecylthio-octadecanal-2- (3 '»5'-dimethyl-4'-hydroxyphenyl) acetyl hydrazone

n-Octylthioethanol-3- (3'-methyl-5'-t-butyl-4'-hydroxyphenyl) propionyl hydrazone

n-Dodecylthiopropanal-3- (3 '»6 ^! -di-t-butyl-4 ¹ -hydroxyphenyl) -propionylhydrazone.

EXAMPLE 7

Preparation of Nl, 7-dimethyl-4-heptylidene-N ^l -3 ^l - (3 ", 5" -di-t- butyl-4 "-hydroxyphenyl) -propionylhydrazone

A 3- (3 *, 5'-di-tbutyl-4 ¹ -hydroxyphenyl) propionyl hydrazide (14.62 g, 0.05 mol), diisobutyl ketone (7.82 g, 0.055 mol) prepared according to Example 1 The mixture consisting of 2-propanol (100 ml) is stirred and refluxed for 5 hours. A catalytic amount (0.5 ml) of boron

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trifluoride etherate (47% w / v) and reflux for a further 1.5 hours. After cooling to room temperature and distilling the solvent under reduced pressure, a residue consisting of 20.6 g of white solid is obtained. Two recrystallizations from heptane deliver 13.2 g of product of melting point 132-9 ⁰ C. After 5 hours of drying at 100 ° / 0, l Torr yields the following analysis. Calculated for C ₂₆ H ₄₄ N ₂ O ₂ : C, 74.95; H, 10.65; N, 6.72 Found: C, 75.17; H, 11.07; N, 6.61 The following compounds are prepared according to the procedure of Example 7, but using the appropriate starting materials:

a) 5-Methyl-3-heptylidene-3 '- (3 ", 5"-di-t-butyl-4' hydroxyphenyl) propionyl hydrazone - melting point 114-120 ⁰ C.

b) 4-Methyl-2-octylidene-3 ^f - (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) -propionyl-hydrazone - yellow syrup

c) N-a-n-Butylbenzylidene-N'-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl ) propionyl hydrazone - melting point 161-163 ° C.

As indicated above, the sterically hindered phenol hydrazone compounds described above are used as stabilizers useful for butadiene-containing rubber. Furthermore are these compounds can also be used as stabilizers for natural and synthetic oils, in particular as stabilizers for turbine oils. The following examples serve further Illustrative of the present invention, and more particularly, it relates to those with the hydrazone compounds described above stabilized masses.

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Extraction of the stabilizer from commercially available rubber

The rubber substrates used in the tests described below are commercially available materials that contain the commercially available stabilizer BHT. Before such rubbers can be used for testing, one must therefore first extract the BHT from the substrate. This is done by dissolving the rubber (polybutadiene or polyisoprene) in toluene and precipitation with isopropanol. This is repeated twice, after which the rubber is vacuumed at room temperature is dried to constant weight.

Stabilization of polybutadiene during processing

Dried polybutadiene (Solprene 235), from which the commercially available stabilizer BHT has been removed, and the desired amount of the hydrazone stabilizer according to the invention are quickly added to a Brabender Plasticorder mixer and mixed. When the blades are rotating, the recording of the torque begins on the recorder. The mixing is continued for 30 minutes or until the crosslinking of the sample at 60 rpm and 150 ⁰ C. As the mixing proceeds, the torque generally decreases gradually until crosslinking occurs. If the torque is plotted against the time, the slope of the curve is initially negative, but becomes positive at the start of the meshing. The point in time at which networking occurs appears as a turning point in the curve.

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TABLE I.

stabilizer

Time to network

Blind test

0.1% compound from Example 3

0.1% "■■» 5

1 Min 10 ti 15th It 8th Il 5 Il 19th dd 8th ti 19th Il 9 ti 15th dd 26th Il 30th It 25th dd 25th dd 25th It 30th Il

Blind test

0.2% compound from example 6 (b) 0.2% "» « 6 (a) 0.2%» »« 6 (j) blank test

0.2% compound from Example 6 (c)

0.2% It 0.2% dd 0.2% dd 0.2% ti 0.2% ti

dd 6 (d) Il 6 (e) It 6 (f) dd 7th It 6 (g)

Note: The horizontal lines in the table above separate different test series from each other, which lead to different Times were running.

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Oven aging of polybutadiene at 70 ° C. The desired amount of stabilizer is incorporated into polybutadiene (Solprene 235 after extraction of the commercially available stabilizer) under nitrogen at 110 ° C. in a Brabender Plasticorder. The stabilizer is added after kneading for one minute and the rubber is mixed for a further four minutes. 1.78 mm 2.54 cm 2.54 cm panels are compression-molded from the mixed rubber. In order to determine the start of gelation, the plates are then ^{aged at 70 °} C. in the oven. Polybutadiene is usually so soft that it can be easily cut with a spatula or fingernail. When crosslinked, it hardens and finally becomes brittle. Gelation begins at the point in time when the sample can no longer be easily cut with a spatula or fingernail, but nevertheless returns to its original shape after the spatula has been removed. The results of the aging test are given in the table below.

TABLE II

Stabilizer onset of gelation

Blind test 65 hours

0.1% compound from Example 3 1014 "

0.1% compound from example 5 590 "

0.2% compound from Example 6 (b) 672 "

0.2% compound from Example 6 (3) 384 ^w

Note: The horizontal lines in the table above separate different test series from each other, which lead to different Times were running.

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Oven aging of polyisoprene at IQO ⁰ C

A stabilizer is incorporated into rubber at a concentration of the specified level under nitrogen in a Brabender Plasticorder for four minutes at HO ^{0 C.} 0.635 mm thick compression molded plates of 5.08 cm 2.54 cm χ χ 0.635 mm and about 1 g weight are aged in a circulating air oven at 100 ⁰ C.

When the decomposition begins, the sample becomes sticky and soft. At the first sign of stickiness, the Sample regarded as failed.

The sterically hindered phenol hydrazone compounds according to the invention can be combined with other known additives such as ozone protection agents, UV light protection agents and light-absorbing agents, metal deactivators and others, as in the German Offenlegungsschrift 2,427,853 at pages 18-24.

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Claims (16)

275661? PATENT CLAIMS: 1. Sterically hindered phenol hydrazones of the formula CH ₀ CNHN = CR, η ZTitt j wherein R ^ is hydrogen or straight or branched chain Alkyl with 1 to 8 carbon atoms, Rp for straight chain or branched alkyl with 1 to 8 carbon atoms, η for an integer from 1 to 5, R 'for hydrogen or alkyl with 1 to 8 carbon atoms and R, for alkyl of 1 to 18 carbon atoms or represents phenyl which is optionally substituted by 1 to 3 alkyl groups having 1 to 4 carbon atoms interrupted alkyl groups of the formulas ^and is selected, where ρ and t are independently integers from 1 to 18 and R ^ is an alkyl group having 1 to 17 carbon atoms or an olefinic group of the formula - (CH ₂ ) _Z -CH = CH (CH ₂ ) CH , in which ζ and y are independently integers from 1 to 12, or R-, the Group -" , U I CH ₀ -CKHN = C-Τη Zn - 16 - _ ^ 809828/0586 ORIGINAL INSPECTED represents where T is a direct bond, alkylene having 1 to 6 carbon atoms, or interrupted by sulfur or oxygen Alkylene of the formula - (C Hp4X- (C ft4, where X Sulfur or oxygen and a is an integer from 1 to 6. 2. Compounds according to claim 1, characterized in that R, and Rp branched alkyl groups, each in the ortho position to hydroxyl, η 2 and R, an interrupted alkyl group with ρ represent 2 to 6 and t represent 8 to 18. 3. Compounds according to claim 2, characterized in that R and Rp are tert-butyl groups. 4. n-Dodecylthio-3-methylpropanal-3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) propionyl hydrazone as a connection according to claim 5. n-dodecylthio-propanal-3- (3 ', 5'-t-butyl-4 ¹ -hydroxyphenyl) propionyl hydrazone as a compound according to claim 1. 6. 01eoylethylthio-2-methylpropanal-3 '- (3 ", 5" -di-t-butyl-4 "-hydroxyphenyl) -propionylhydrazone as a compound according to claim 1. 7. Compounds according to claim 1, characterized in that that R and Rp are branched alkyl groups, each in the ortho position to hydroxyl, η 2 and R ^ hydrogen, alkyl or phenyl represent. 8. Compounds according to claim 7, characterized in that R ₁ and Rp are tert * -butyl groups. 9. n-Dodecylal-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionyl hydrazone as a compound according to claim 8. 10. Isovaleral-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) - ~ ¹⁷ ~ 8 09828/0586 Propionyl hydrazone as a compound according to claim 8. 11. Compounds according to claim 1, characterized in that R ₁ and R ₂ branched alkyl groups, each in the ortho position to the hydroxyl, η 2 and R, a group of the formula ? 2 1 j OR ^x HO (O) C _n H _2n -CNHN = CT- ^R l represent. 12. Compounds according to claim 11, characterized in that R ₁ and R _{2 are} tert «-butyl groups. 13. Butadiene-containing rubber stabilized against thermal and oxidative degradation, characterized in that 0.01 to 5 wt .-% of a compound according to claim 1 are incorporated therein. 14. masses according to claim 13 »characterized in that said rubber is selected from polybutadiene, styrene / butadiene copolymer, acrylonitrile / butadiene / styrene copolymer and polyisoprene is. 15. Composition according to claim 14, characterized in that said rubber is polybutadiene. 16. Compounds according to claim 13 »characterized in that the hydrazone stabilizer is 3- (3 ', 5'-di-t-butyl-4 ¹ -hydroxyphenyl) propionyl (n-tridecylthio-2-methylpropanal) hydrazone. - 18 - 809828/0586