Microstructure-bearing composite plastic articles and method of making

• US 5,175,030 A
• Filed: 12/08/1989
• Issued: 12/29/1992
• Est. Priority Date: 02/10/1989
• Status: Expired due to Term

• Current Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Original Assignee: Minnesota Mining and Manufacturing Co (3M Company)
• Inventors: Williams, Todd R., Lu, Shih-Lai
• Primary Examiner(s): Thibodeau, Paul J.
• Assistant Examiner(s): NAKARANI, DHIRAJLAL S
• Application Number:
  US07/444,361
• Time in Patent Office: 1,117 Days
• Field of Search: 428/412, 428/36.9, 428/36.91, 428/30, 428/172, 428/906, 362/31, 362/32
• US Class Current: 428/30
• CPC Class Codes: B29C 2035/0827 using UV radiation
• CPC Class Codes: B29C 35/08 by wave energy or particle radiation B29C64/00, B29C71/04 take precedence
• CPC Class Codes: B29D 11/00605 Production of reflex reflectors
• CPC Class Codes: B32B 37/24 with at least one layer not being coherent before laminating, e.g. made up from granular material sprinkled onto a substrate B32B37/15 takes precedence
• CPC Class Codes: B32B 38/06 Embossing
• CPC Class Codes: G11B 7/26 Apparatus or processes specially adapted for the manufacture of record carriers
• CPC Class Codes: Y10T 428/139 Open-ended, self-supporting conduit, cylinder, or tube-type article
• CPC Class Codes: Y10T 428/1393 Multilayer [continuous layer]
• CPC Class Codes: Y10T 428/24612 Composite web or sheet
• CPC Class Codes: Y10T 428/31507 Of polycarbonate

Abstract

A microstructure-bearing composite plastic article can be superior, both in microstructure and in physical properties, when it is a composite of a tough, flexible substrate, at a surface of which is microstructure formed of a cured oligomeric resin having hard segments and soft segments, which cured resin is substantially confined to the microstructure portion of the composite. Such a composite plastic article can be made by depositing an uncured oligomeric resin composition onto a master negative molding surface in an amount barely sufficient to fill the cavities of the master, filling the cavities by moving a bead of the composition between a substrate and the master, and curing the deposited composition by ultraviolet radiation while keeping the temperature during curing to not more than 50° C. above the typical use temperature of the finished composite plastic article.

Claims

1. A composite plastic article comprising a tough, flexible substrate, one face of which bears a microstructure of utilitarian discontinuites, which discontinuities have a depth of at least 0.025 mm to about 0.5 mm, said microstructure comprising a layer of a cured oligomeric resin having hard segments and soft segments, wherein the total thickness of the layer of cured resin is not more than 20% greater than the depth of the discontinuities.

2. A composite plastic article as defined in claim 1, wherein the substrate comprises a tough, flexible, transparent, thermoplastic film.

3. A composite plastic article as defined in claim 2, the substrate of which is a flexible polycarbonate film.

4. A composite plastic article as defined in claim 2, wherein said microstructure makes the composite plastic article a total internal reflecting film.

5. A composite plastic article as defined in claim 4, and formed into a light pipe having a diameter of less than 7.5 cm.

6. A composite plastic article as defined in claim 1 wherein said utilitarian discontinuities comprise optically utilitarian discontinuities.

7. A composite plastic article as defined in claim 1 wherein each surface of said flexible substrate bears a microstructure of said utilitarian discontinuites.

8. A composite plastic article according to claim 1 wherein said cured oligomeric resin has an experimentally determined thermal expansion coefficient that is from 1.33 to 6 times greater than the experimentally determined thermal expansion coefficient of said flexible substrate.

9. A composite article according to claim 8 wherein the experimentally determined thermal expansion coefficient or said flexible substrate is in the range of 0.3×

10^-4 mm/mm/°

C. to 1.5×

10^-4 mm/mm/°

C. and said cured oligomeric resin has an experimentally determined thermal expansion coefficient in the range of 2×

10^-4 mm/mm/°

C. to 3×

10^-4 mm/mm/°

C.

10. A composite article according to claim 9 wherein one of the hard and soft segments of said cured oligomeric resin has a Tg below room temperature and said flexible substrate has a Tg above room temperature.