Composite plastic with laser altered internal material properties

• US 4,822,973 A
• Filed: 09/28/1987
• Issued: 04/18/1989
• Est. Priority Date: 03/30/1984
• Status: Expired due to Fees

• Current Assignee: Bayer AG
• Original Assignee: Bayer AG
• Inventors: Fahner, Karsten, Depcik, Hans-Werner
• Primary Examiner(s): Albritton, C. L.
• Application Number:
  US07/079,515
• Time in Patent Office: 568 Days
• Field of Search: 219/121.66, 219/121.85, 219/121.65, 219/121.6, 346/76 L
• US Class Current: 219/121.6
• CPC Class Codes: B23K 2103/16 Composite materials , e.g. fibre reinforced
• CPC Class Codes: B23K 2103/42 Plastics B23K2103/16 takes precedence
• CPC Class Codes: B23K 26/0006 taking account of the properties of the material involved B23K26/32, B23K26/40 take precedence
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser

Abstract

An identification mark which remains permanently readable is applied by means of a laser beam through a lightwave window of plastics material to a plastics layer situated behind that window.

Claims

1. A composite plastic part of thermoplastic materials having good adhesion and compatability with one another and similar contraction behavior and having material properties altered by a laser beam, the composite plastic part having a thermoplastic surface layer with a layer thickness of from 0.1 to 2 mm, a light transmission value τ

of greater than 0.8 and more particularly greater than 0.9 at a wavelength of from 1000 to 20,000 um, and an internal thermoplastic material region below the surface layer with a light absorption value to a depth of 2 mm of greater than 80% of incident laser beams, internal thermoplastic material region containing a subsequently laser induced change therein.

2. A composite plastic part as in claim 1 wherein the internal thermoplastic material region contains metallic inclusions.

3. A composite plastic part as in claim 1 wherein the internal thermoplastic material region consists of polyacrylonitrile.

4. A composite plastic part as in claim 1 wherein the subsequently laser induced change in the internal thermoplastic material region is in the form of a carbonized electrically conductive path.

5. A composite plastic part as in claim 3 wherein the subsequently laser induced change in the internal thermoplastic material region is in the form of a carbonized electrically conductive path.

6. A composite plastic part as in claim 1 wherein one thermoplastic material is cellulose acetate and the other thermoplastic material is at least one of acrylonitrile-butadiene-styrene, cellulose acetate and ethylene vinyl acetate.

7. A composite plastic part as in claim 1 wherein one thermoplastic material is polycarbonate and the other thermoplastic material is at least one of polycarbonate and acrylonitrile-butadiene-styrene.