System and method for curing polymeric moldings

• US 7,384,590 B2
• Filed: 12/10/2003
• Issued: 06/10/2008
• Est. Priority Date: 12/17/2002
• Status: Active Grant

• Current Assignee: Alcon Incorporated
• Original Assignee: Novartis Ag
• Inventors: Burnett, George E., Kelly, William Michael, Gilliard, Allen
• Primary Examiner(s): Vargot; Mathieu D.
• Application Number:
  US10/732,566
• Publication Number:
  US 20040178541A1
• Time in Patent Office: 1,644 Days
• Field of Search: 425/808, 425/174.4, 249/116, 249/134, 249/135, 264/1.1, 264/2.5, 264/1.36, 264/1.38, 264/104, 264/105, 264/494, 264/496
• US Class Current: 264/496
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/0888 using transparant moulds
• CPC Class Codes: B29L 2011/0016 Lenses
• CPC Class Codes: Y10S 425/808 Lens mold

Abstract

A system and method for forming a polymeric molding. A mold component includes a UV-absorptive material for preventing undesired reflection or transmission of curing energy within the mold cavity, thereby providing more precise control of the edge geometry of the molding.

Claims

1. A molding system comprising first and second mold components, said first mold component comprising a generally circular disc-shaped transmissive portion and a masking collar having an inner diameter adapted to fit in close engagement with the transmissive portion, wherein said transmissive portion is made from an optically clear material and allows passage of curing energy therethrough, and wherein the masking collar is made from a material comprising a UV-blocker and substantially blocks passage of curing energy therethrough, wherein said masking collar comprises a polymeric material impregnated with carbon black filler, wherein the masking collar generally resembles a washer or a doughnut, with a center hole for receiving the transmissive portion, wherein the transmissive portion is pressed into the center opening of the masking collar and the masking collar is mounted within a bushing sleeve, said second mold component comprising a UV-absorptive material.

2. The molding system of claim 1, wherein the said second mold component comprising said UV-absorptive material comprises a female mold profile.

3. The molding system of claim 1, wherein said UV-absorptive material comprising a cyclic-olefin copolymer impregnated with a UV-blocking filler.

4. The molding system of claim 1, wherein said second mold component comprises a female mold profile.

5. The molding system of claim 1, wherein said second mold component is mounted within a bushing sleeve.

6. A molding system comprising:

a first mold component comprising a generally circular disc-shaped UV-transmissive portion and a masking collar having an inner diameter adapted to fit in close engagement with the transmissive portion, wherein said transmissive portion is made from an optically clear material and allows passage of curing energy therethrough, and wherein the masking collar is made from a material comprising a UV-blocker and substantially blocks passage of curing energy therethrough, wherein said masking collar comprises a polymeric material impregnated with carbon black filler, wherein the masking collar generally resembles a washer or a doughnut, with a center hole for receiving the transmissive portion, wherein the transmissive portion is pressed into the center opening of the masking collar and the masking collar is mounted within a bushing sleeve; and

a second mold component comprising a UV-absorptive material that is generally transparent to infrared energy,

wherein the first and second mold components are engageable to define a mold cavity and wherein said UV-absorptive material is a cyclic-olefin copolymer impregnated with a UV blocking filler.

7. The molding system of claim 6, wherein the first mold component comprises a male mold profile, and wherein the second mold component comprises a female mold profile.

8. A method of forming a polymeric molding, said method comprising

engaging a first mold component and a second mold component to define a mold cavity, said first mold component comprising a generally circular disc-shaped transmissive portion and a masking collar having an inner diameter adapted to fit in close engagement with the transmissive portion, wherein said transmissive portion is made from an optically clear material and allows passage of curing energy therethrough, and wherein the masking collar is made from a material comprising a UV-blocker and substantially blocks passage of curing energy therethrough, wherein said masking collar comprises a polymeric material impregnated with carbon black filler, wherein the masking collar generally resembles a washer or a doughnut, with a center hole for receiving the transmissive portion, wherein the transmissive portion is pressed into the center opening of the masking collar and the masking collar is mounted within a bushing sleeve and said second mold component comprising a UV-absorptive material;

depositing a dose of prepolymer material within the mold cavity; and

exposing at least a portion of the prepolymer material to UV energy through the UV-transmissive portion of the first mold component; and

reducing reflection of UV energy within the mold cavity by absorption of incident energy upon the UV-absorptive material of the second mold component.

9. The method of claim 8, wherein the first mold component comprises a male mold profile, and wherein the second mold component comprises a female mold profile, and wherein the step of depositing a dose of prepolymer material within the mold cavity comprises depositing prepolymer material within the second mold component prior to engaging the first and second mold components.