Use of UV absorbers in the production of transparent polyamide molded parts

A method of reducing deposits on production tool surfaces in the production of transparent polyamide products or transparent polyamide molded parts, wherein the method comprises:

• (a) providing in a mixer or extruder a polyamide molding material comprising at least 50 wt. % polyamide consisting of at least one transparent polyamide, a mixture of transparent polyamides, or a blend of transparent polyamides with at least one partially crystalline polyamide;
• (b) adding to said polyamide molding material in the mixer or extruder at least one UV absorber selected from a group consisting of 1-(4-methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione and 2-(4′-diethylamino-2′-hydroxybenzoyl)benzoic acid-n-hexylester in a fraction between 0.01 and 1.0 wt. % relative to the weight of the polyamide molding material;
• and
• (c) thermoplastically processing the mixture produced of (a) and (b) by injection molding, injection compression molding, closure embossing, expansion embossing, or extrusion to produce transparent polyamide products or transparent polyamide molded parts,
• melts of the polyamide molding material comprising said at least one UV absorber leave no visible blooming on surfaces with which they come into contact during processing or production of transparent polyamide products or transparent polyamide molded parts.

A method of reducing deposits on production tool surfaces in the production of transparent polyamide products or transparent polyamide molded parts, wherein the method comprises:

• (a) providing in a mixer or extruder a polyamide molding material comprising at least 50 wt. % of polyamide consisting of at least one transparent polyamide, a mixture of transparent polyamides, or a blend of transparent polyamides with at least one partially crystalline polyamide;
• (b) adding to said polyamide molding material in the mixer or extruder an UV absorber which is a mixture of 1-(4-methoxyphenyl)-3-(4-tert-butylphenyl)propane-1,3-dione and 2-(4′-diethylamino-2′-hydroxybenzoyl)benzoic acid-n-hexylester;
• in a fraction between 0.01 and 1.0 wt. % relative to the weight of the polyamide molding material;
• and
• (c) thermoplastically processing the mixture produced of (a) and (b) by injection molding, injection compression molding, closure embossing, expansion embossing, or extrusion to produce transparent polyamide products or transparent polyamide molded parts,
• wherein melts of the polyamide molding material comprising said UV absorber leave no visible blooming on surfaces with which they come into contact during processing or production of transparent polyamide products or transparent polyamide molded parts.