Method of making a plastic material sensitive to laser radiation and enabling it to be marked by a laser, and articles obtained thereby

• US 4,816,374 A
• Filed: 04/09/1986
• Issued: 03/28/1989
• Est. Priority Date: 04/12/1985
• Status: Expired due to Term

• Current Assignee: Societe D'Applications Plastiques Rhone-Alpes
• Original Assignee: Societe D'Applications Plastiques Rhone-Alpes
• Inventors: Lecomte, Gilbert
• Primary Examiner(s): Michl, Paul R.
• Assistant Examiner(s): Wright, Lee C.
• Application Number:
  US06/849,776
• Time in Patent Office: 1,084 Days
• Field of Search: 430/964, 430/495, 430/945, 430/346, 430/374, 430/270, 430/906, 430/18, 346/135.1, 524/409
• US Class Current: 430/270.1
• CPC Class Codes: A01K 11/001 Ear-tags
• CPC Class Codes: B29C 2035/0838 using laser
• CPC Class Codes: B29C 59/16 by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: B44B 7/00 Machines, apparatus or hand tools for branding, e.g. using radiant energy such as laser beamsburning or charring wood stock B27M1/06
• CPC Class Codes: G09F 3/00 Labels, tag tickets, or similar identification or indication means medals or badges A44C3/00; making labels B31D1/02; sheets temporarily attached together B42F; labelling B65C; labels on record carriers G11B23/38, G11B23/40; Seals; Postage or like stamps
• CPC Class Codes: Y10S 430/146 Laser beam
• CPC Class Codes: Y10S 430/165 Thermal imaging composition

Abstract

An opacifier substance is added to a plastic material which is naturally transparent to laser radiation. The opacifier substance is added in powder form as a concentration of 2% to 6% by weight of the plastic material. The opacifier substance is preferably antimony oxide and the resulting plastic material is capable of being permanently marked by a laser beam and is suitable for providing animal ear tags. These tags may be marked with an automatically readable bar code and this code continues to be automatically readable over a period of several years use on the animal.

Claims

1. A method for marking a plastic material by laser radiation whereby the markings thereon are readable by an optical reader, comprising:

(1) uniformly distributing in a plastic material a sufficient amount of a laser radiation opacifier substance selected from the group consisting of antimony, antimony oxide and mixtures thereof, such that the resulting plastic is markable by laser radiation but wherein the said amount is not sufficient to substantially degrade the physical properties of the said plastic;

(2) forming the plastic material into a configuration adaptable to laser radiation;

(3) exposing the formed plastic material to laser radiation such that the formed plastic is permanently marked by the laser radiation so that the markings are easily readable.

2. A method according to claim 1, wherein the concentration of added opacifier substance lies in the range 2% to 6% by weight of the basic plastic material.

3. A method according to claim 1, wherein the opacifier substance is added in the form of a powder whose particles are finer than the particles of the plastic material.

4. A method according to claim 1, wherein the opacifier substance is added in the form of particles which are about 1/20 of the size of the particles of the plastic material.