Methods for laser welding articles molded from polyolefins to those molded from other thermoplastic resins, and welded articles prepared therefrom

Abstract

Processes for laser welding polyolefin compositions to different thermoplastic resins are disclosed. Such polyolefin compositions comprise 80-99 weight percent of a first polyolefin and 1 to 20 weight percent of a second polyolefin (modified with a carboxylic acid, a carboxylic acid anhydride, and/or an epoxy group), based on the total weight of the polyolefin and modified polyolefin. These compositions can be laser welded to polyamides and polyesters, for example. Additives such as flame retardants, impact modifiers and the like may be incorporated in conventional amounts. Moreover, black colorants may also be selected for use in these compositions for molding transparent articles for laser welding. Laser welded articles made using these processes are also contemplated.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application No. 60 / 497,253 filed Aug. 22, 2003, which is incorporated by reference herein for all purposes as if fully set forth.BACKGROUND OF THE INVENTION [0002] It is known in the art to join together two molded parts made from polymer resins where one part (the “transparent” part) is at least partially transparent to a laser beam at a given wavelength and the other part absorbs a significant portion of incident light at that wavelength (the “opaque” part), by positioning them to contact along adjoining surfaces, irradiating the surface of the transparent part with a laser beam at the given wavelength such that at least a portion of the laser energy is transmitted to the junction of the transparent and opaque parts, causing the polymer at the junction of the two parts to be melted and joined together. This technique is commonly referred to as “laser welding”. Several advantages f...

AI Technical Summary

Problems solved by technology

When selecting thermoplastic resins for laser welding, the materials chosen for each part are typically miscible with each other.

There are disadvantages and difficulties associated with attempting to laser weld together two molded parts made of different thermoplastic resins that are not miscible with each other.

Thus, a longstanding problem in the field of laser welding has been the difficulty in using the technique to join parts

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