Ciba-geigy Corporation

Sankyo Company, Limited

Heimo Brunetti

Jean Rody

Tomoyuki Kurumada

Nobuo Soma

Hanns Lind

Ivan Orban

Siegfried Rosenberger

Helmut Muller

Kurt Schwarzenbach

Michael Rasberger

Martin Dexter

Andreas Schmidt

Bernard Gilg

Martin Knell

Rolf Hugi

Zdenek Mazour

Derivatives of sterically hindered 4-aminopiperidines are effective as light-stabilizers for organic polymers, especially for polyolefins. The piperidine ring is substituted with at least five alkyl groups, preferably methyl and ethyl groups. The 4-amino group is substituted with mono- or divalent acyl groups. The nitrogen in 1-position may also be substituted with a monovalent organic substituent. The compounds can be synthesized starting from higher homologs of acetone in sequence of several reaction steps.

Derivatives of 4-aminopiperidine as stabilizers for polymers

Polymers, both natural and synthetic, are stabilized against the deterioration resulting from heat and/or light by the incorporation of certain 2,2,6,6-tetra-substituted-4-piperidinol derivatives which additionally have an alkyl, alkenyl, alkynyl or aralkyl substituent at one or both of the 3- and 5- positions.

Stabilization of synthetic polymers by penta-or-hexa-substituted

Sterically hindered piperidines having at least 5 alkyl groups in ring positions 2,3,5 and 6 are usable as light-stabilizers for organic polymers. The nitrogen may be unsubstituted or may bear a mono- to tetravalent substituent. The compounds can be synthesized by a Wolf-Kishner reduction of polyalkyl 4-oxopiperidines optionally followed by a N-substitution reaction in a second step. The stabilizers are added to the polymers in an amount of from 0.01 to 5% by weight. Preferred is the stabilization of polyolefins, styrene polymers, polyamides and polyurethanes.

Stabilization of poly(mono-olefins)

Cyclic ketals of sterically hindered 4-oxopiperidines are effective light-stabilizers for organic polymers. These compounds have at least five alkyl groups in ring positions 2,3,5 and 6 and four alkyl groups in ring positions 2 and 6, preferably methyl and ethyl groups. The ring nitrogen may be unsubstituted or substituted with a monvalent substitutent. The new compounds can be synthesized by ketalization of the corresponding 4-oxopiperidines with diols, triols or tetrols. Using triols the obtained ketals possess hydroxyl groups which may be esterified or etherified in a subsequent reaction step. Ketalization with tetrols yields cyclic bis-ketals.

Derivatives of 4-oxopiperidines and their use as polymer stabilizers

Novel 7,7,9,9-tetra-substituted-1,3,8-triazaspiro�4.5!decane-2,4-diones having an alkyl or allyl group at either the 6- or the 10- position are useful for the stabilization of polymers against photo- and thermal- deterioration.

1,3,8-Triazaspiro�4.5!decane-2,4-dione polymer stabilizers

Stabilization of polymers by penta- or hexa-substituted 4-piperidinol

A process for stabilizing homo- or copolymeric polyolefins, especially polypropylene, with certain symmetrical or asymmetrical diacyl dihydrazides is disclosed, said diacyl dihydrazides possessing good color properties, and said process being particularly advantageous with respect to thermooxidative decomposition in the presence of transition metals.

Stabilizing polyolefins with diacyl dihydrazides

Process for the production of phosphite chlorides comprising the reaction of phosphorus trichloride and a trialkyl phosphite or a triphenyl phosphite in the presence of a hydrous quaternary compound of nitrogen or phosphorus.

Process for the production of phosphite chlorides

1,2-Diacylhydrazines are prepared by a new process by reacting acylhydrazides and carbonic acids in the presence of an inorganic acid chloride.

Process for the manufacture of acylhydrazines

N,N'-bis-salicyloyl-hydrazine is a suitable stabilizer for polymers against deterioration induced by transition metals.

Bis-salicyloyl-hydrazine as stabilizer for polymers

New 3,5-dialkyl-4-hydroxybenzyl-oxiranes and the corresponding thiiranes are used as stabilizers for polymers. The oxiranes are prepared from the corresponding olefins by reaction with percarboxylic acids or from alkali phenoxides and epichlorohydrines. The thiiranes are prepared from the oxiranes by the usual sulfidation methods.

3,5-DIALKYL-4-HYDROXYBENZYL-OXIRANES

2,2,6,6-Tetramethyl-4-oxopiperidine is prepared from 2,2,4,4,6-pentamethyl-2,3,4,5-tetramethylpyrimidine (acetonine) by heating in the presence of acetone, diacetone alcohol or water. These regents may be used in excess or an organic solvent is added. The preferred modification is the heating of acetonine hydrate in an excess of acetone or in an acetone-methanol mixture to about 40.degree. to 65.degree.C for several hours. The use of diacetone alcohol permits higher reaction temperatures leading to shorter reaction times.

Process for the preparation of 2,2,6,6-tetramethyl-4-oxopiperidine

Bicyclic phosphites are used alone or in combination with other stabilisers for stabilising polyolefines.

Bicyclic phosphites

2,2,6,6-Tetramethyl-4-oxopiperidine is prepared from acetone and ammonia in the presence of acidic catalysts. Suitable catalysts are Lewis acids, protionic acids and their salts with ammonia or with organic bases, as for example BF.sub.3, NH.sub.4 Cl or H.sub.2 SO.sub.4. The addition of an alcohol such as methanol as well as the use of a cocatalyst may promote the reaction. The process may be carried out in two steps, in the first of which the temperature is held below 35.degree.C. In the second step a further amount of acetone is added and the temperature is rised to about 40.degree. to 65.degree.C.

2,2,6,6-Tetramethyl-4-oxopiperidine is prepared from 2,2,4,4,6-pentamethyl-2,3,4,5-tetrahydropyrimidine by treatment with an acidic catalyst. Suitable catalysts are Lewis acids, protonic acids and their salts with ammonia or organic bases. The reaction may be carried out in organic solvents, preferably in acetone, by gentle heating, for example at 40.degree. to 65.degree.C. Yields of 95% are obtainable after a reaction of several hours.

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Reinach, Switzerland

Heimo Brunetti