Pigments and compositions for use in laser marking

• US 6,825,265 B2
• Filed: 11/21/2001
• Issued: 11/30/2004
• Est. Priority Date: 11/21/2000
• Status: Expired due to Term

• Current Assignee: TE Connectivity Solutions GmbH (TE Connectivity Ltd. (United Kingdom))
• Original Assignee: Tyco Electronics Corporation (TE Connectivity Ltd. (United Kingdom))
• Inventors: Daga, Vijay, Dahl, Klaus J.
• Primary Examiner(s): Moore, Margaret G.
• Assistant Examiner(s): Zimmer, Marc S
• Application Number:
  US09/990,107
• Publication Number:
  US 20020155291A1
• Time in Patent Office: 1,105 Days
• Field of Search: 524/430, 524/544, 524/545, 524/546, 428/405
• US Class Current: 524/544
• CPC Class Codes: B41M 5/267 Marking of plastic artifacts, e.g. with laser
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/50 Agglomerated particles
• CPC Class Codes: C01P 2004/54 Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/62 Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/84 one phase coated with the other
• CPC Class Codes: C01P 2006/12 Surface area
• CPC Class Codes: C01P 2006/60 Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C01P 2006/80 Compositional purity
• CPC Class Codes: C08K 9/06 with silicon-containing compounds
• CPC Class Codes: C08L 27/12 containing fluorine atoms
• CPC Class Codes: C09C 1/04 Compounds of zinc C09C1/0003, C09C1/0009, C09C1/0015, C09C1/0078 take precedence
• CPC Class Codes: C09C 1/043 Zinc oxide
• CPC Class Codes: C09C 1/3684 Treatment with organo-silicon compounds
• CPC Class Codes: C09C 3/12 Treatment with organosilicon compounds C09C3/006 takes precedence
• CPC Class Codes: H01B 3/305 Polyamides or polyesteramides
• CPC Class Codes: H01B 3/306 Polyimides or polyesterimides
• CPC Class Codes: H01B 3/445 from vinylfluorides or other fluoroethylenic compounds
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2995 : Silane, siloxane or silicone coating

Abstract

Pigments and compositions for use in laser marking. A colorless UV-absorbing pigment at least partially coated with a synergist has the formula

[R_m(SiO_n)]_pR′_q,

wherein (a) m is 1 to 3, n is 1 to 3, p is at least 1, and q is 0 to 3, and (b) at least one R or R′ is a substituent that upon pyrolysis generates a black material suitable for providing a mark. Such pigments are useful in fluoropolymers used for wire and cable insulation.

Claims

1. A composition suitable for laser marking when exposed to radiation from an excimer laser, said composition comprising

(1) a fluoropolymer having a processing temperature T_p,

(2) 0.1 to 50% by weight of the composition of a colorless UV-absorbing pigment, and

(3) a synergist having the formula

2. A composition according to claim 1 wherein the fluoropolymer is a melt-processible fluoropolymer.

3. A composition according to claim 2 wherein the fluoropolymer comprises PFA, MFA, ETFE, or FEP.

4. A composition according to claim 1 wherein the fluoropolymer comprises PTFE.

5. A composition according to claim 1 wherein the synergist comprises a silsesquioxane or a polyhedral oligomeric (POSS).

6. A composition according to claim 5 wherein the synergist comprises dodecaphenylsilsesquioxane.

7. A composition according to claim 1 wherein the synergist is present at at least 20% by weight of the pigment.

8. A composition according to claim 1 wherein the pigment comprises TiO₂, ZnO, or ZnS.

9. A composition suitable for laser marking when exposed to radiation from an excimer laser, said composition comprising

(1) polytetrafluoroethylene,

(2) 0.1 to 50% by weight of the composition of a colorless UV-absorbing pigment, and

(3) a synergist having the formula

10. An insulated conductor which comprises

(A) an elongate wire, and

(B) an insulating layer surrounding said wire, said layer comprising a composition which comprises

(1) a fluoropolymer having a processing temperature T_p,

(2) 0.1 to 25% by weight of the composition of a colorless UV-absorbing pigment, and

(3) a synergist having the formula

11. A conductor according to claim 10 wherein the composition comprises a perfluoropolymer.

12. A conductor according to claim 11 wherein the periluoropolymer is PTFE.

13. A conductor according to claim 12 wherein the synergist comprises dodecaphenylsilsesquioxane.

14. A conductor according to claim 10 which, when exposed to an excimer laser at a wavelength of 308 nm and a fluence of 800 mJ/cm², produces a mark having a contrast of at least 70%.