PROCESS FOR STABILIZING POLYOLEFINE PRODUCTS

• Main Authors: GORINI,GIUSEPPE,IT, CASELLI,GIANCARLO,IT
• Format: Patent
• Language: English
• Published: 28.06.1991
• Edition: 5
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WORKING-UP

Disclosed are olefin polymers in nonextruded, aspolymerized particle form having a regular, essentially symmetrical geometrical shape, which are stabilized by depositing on their surface a mixture which is either melted, or in which at least stabilizer (A) is in the liquid state, and which comprises the following stabilizers (percent by weight on the polymer): A) from 0.02% to 0.015% of one or more organic phosphites or phosphonites or mixtures thereof, which are liquid at room temperature or have melting point below 100 DEG C; B) from 0.025% to 0.2% of one or more phenolic antioxidants with melting point from 45 DEG to 130 DEG C; and, optionally, one or more of the following additional components: C) from 0.05% to 0.5% of one or more thioethers, or organic polysulfides or mixtures thereof; D) from 0.1% to 1.0% of one or more light stabilizers which are liquid at room temperature or have a melting point below 150 DEG C, selected from the group consisting of HALS, benzophenone and benzotriazole derivatives; and E) one or more diluents selected from the group consisting of paraffins and cycloparaffins, which are liquid at room temperature, or have a melting point below 110 DEG C, epoxidized soy bean or linseed oil, silicone oils, and olefin oligomers in an amount not greater than 0.3%. r