Process for manufacturing an automotive trim piece having a polymeric skin mounted to a substrate

A process for manufacture of a belt molding for installation on the exterior of a vehicle door along a lower edge of a window opening, the process comprising the steps of:

• rollforming a metal core to have a generally "U"-shaped cross-section for fitting to the car door with a first leg of the "U" facing outwardly;
• applying a first activatable adhesive to an obverse face of the first leg for adhesively bonding a thermoplastic polymeric layer thereto;
• activating the adhesive to ready the core for application of the polymeric layer to the first leg;
• extruding the thermoplastic polymeric layer onto the obverse face of the first leg;
• applying to the extruded layer an adhesive for bonding a skin of thermoplastic material thereto;
• cutting the core to a predetermined length to form an elongate substrate for the belt molding;
• molding a decorative skin of thermoplastic material in a mold separate from the substrate so as to have a rear face for abutment with the extruded thermoplastic polymeric layer of the substrate, and first and second pairs of lips extending rearwardly from the rear face of the skin, the first pair of lips being located at lengthwise ends of the skin and shaped for engaging abutment with corresponding ends of the substrate, the second pair of lips running from end to end of the skin and shaped for engaging abutment with corresponding edges of the substrate, wherein the thermoplastic material has the property that upon cooling to a relatively rigid state, the skin molded therefrom shrinks;
• partially cooling the skin while in the mold to a non-molten and relatively elastic state;
• removing the skin from the mold while the skin is in the relatively elastic state;
• assembling the skin in the relatively elastic state and the substrate together with the rear face of the skin and the adhesive applied to the extruded layer in contact with each other;
• and
• wherein upon further cooling the skin shrinks with respect to the substrate to produce a snug fit of the substrate between the lips of the skin from end to end and from edge to edge of the substrate and the rear face of the skin is adhesively secured to the extruded layer of the substrate.

A process for manufacture of an automotive trim piece having a substrate with a polymeric skin fastened there,to, the process comprising the steps of:

• preparing the substrate by applying an adhesive to a first area of a metal core for securing a polymeric material to the core;
• extruding a layer of the polymeric material onto the first area of the core;
• applying an adhesive to an obverse face of the extruded polymeric material, for adhering the skin to the extruded polymeric material when the trim piece is assembled;
• cutting the core to length;
• molding the polymeric skin, separately from the substrate from a molten polymer, the skin having a rear face for abutment with the adhesive of the obverse face of the extruded polymeric material, and a pair of lips extending from ends of the rear face of the skin, the lips facing each other for engaging abutment with corresponding edges of the substrate, wherein the polymer has the property that upon cooling to a relatively rigid state, the skin molded therefrom shrinks;
• partially cooling the skin to a non-molten and relatively elastic state;
• assembling the skin, while in the relatively elastic state, and the substrate together with the rear face of the skin and the obverse face of the extruded polymeric material having the adhesive applied thereto in abutting contact and with the edges of the substrate between the lips of the skin;
• and
• further cooling the skin, wherein the lips are located such that when further cooled, the skin lips in abutment with the corresponding edges of the substrate and shrinkage forces of the skin produce a snug fit from edge to edge of the skin to the substrate and the skin becomes relatively rigid.