Sumitomo Chemical Company, Limited

Hiroki Yamamoto

Shinichi Yachigo

Yukoh Takahashi

Tamaki Ishii

Manji Sasaki

Haruki Okamura

Hideo Nagasaki

Yuzo Maegawa

Shinya Tanaka

Isao Kurimoto

Tetsuo Yamaguchi

Tatsuo Kaneoya

Eizo Okino

Takeshi Takata

Masakatsu Yoshimura

Isao Nakamae

Eiiti Yoneyama

Norimitsu Numadate

Crude N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)alkanediamine represented by the formula: ##STR1## wherein n is an integer of 2 to 10, is purified by crystallization from a ketone solvent of 3 to 9 carbon atoms. The purified product thus obtained has a purity of 98% by weight or more, a 2,2,6,6-tetramethyl-4-piperidone content of 150 ppm or less, and an initial APHA value of 30 or less. The purified product is also inhibited from discoloration with the passage of time.

Process for producing

A process for producing granules of a 2,2,6,6-tetramethylpiperidine-containing light stabilizer, which comprises mixing a 2,2,6,6-tetramethylpiperidine-containing light stabilizer having a melting point of not less than 60.degree. C. with a lubricant selected from the group consisting of water and an aqueous solution of an alcohol having 1 to 4 carbon atoms, and granulating the resultant mixture while pressure is applied thereto. The granular light stabilizer product has low dusting property and excellent free-flowing property.

Process for granulating 2,2,6,6-tetramethylpiperidine-containing light

A stabilized polyolefin composition having improved weathering resistance is provided, whereby the following four components are incorporated into a polyolefin:

Stabilized polyolefin composition

An ammonium slat represented by the formula ##STR1## wherein X represents aliphatic group or alicyclic group, each of which may contain halogen, oxygen, nitrogen or sulfur in the group;

Novel ammonium salt useful as modifiers for rubber

A styrene polymer is stabilized by incorporating into said styrene polymer

Stabilized styrene polymer

A stabilizer for synthetic resins containing as an effective ingredient a hindered piperidine compound represented by the general formula: ##STR1## wherein R.sub.1 represents a C.sub.1 -C.sub.18 alkyl group, R.sub.2 represents a hydrogen atom or a C.sub.1 -C.sub.4 alkyl group, n represents an integer of 1 to 12, and C.sub.n H.sub.2n represents a straight-chain or branched alkylene group.

Stabilizer for synthetic resins

Piperidine derivatives represented by the general formula (1) ##STR1## (wherein R.sub.1 is a hydrogen atom, an alkyl group of 1 to 3 carbon atoms or an acyl group of 2 to 18 carbon atoms; and k, m and n each are independently an integer of 1 to 3), a process for producing said derivatives, and stabilizers for organic substances containing said derivatives as an active component.

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Nishinomiya, Japan

Hiroki Yamamoto