Light-transmitting fiber

• US 4,693,553 A
• Filed: 02/26/1985
• Issued: 09/15/1987
• Est. Priority Date: 03/02/1984
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Rayon Company Limited (Mitsubishi Chemical Holdings Corporation)
• Original Assignee: Mitsubishi Rayon Company Limited (Mitsubishi Chemical Holdings Corporation)
• Inventors: Yamamoto, Takashi, Sasaki, Isao, Morimoto, Masaru, Nishida, Kozi
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): Mottola, Steven J.
• Application Number:
  US06/705,634
• Time in Patent Office: 931 Days
• Field of Search: 264/1.5, 264/2.7, 350/96.29, 350/96.30, 350/96.31, 350/96.32, 350/96.33, 350/96.34
• US Class Current: 385/143
• CPC Class Codes: C08L 33/00 Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
• CPC Class Codes: C08L 33/12 Homopolymers or copolymers of methyl methacrylate
• CPC Class Codes: G02B 1/046 characterised by the core material

Abstract

A plastic light-transmitting fiber having a core-sheath structure. A polymer having methacrylimide or N-substituted methacrylimide units is used for the core component. A polymer having a refractive index smaller by at least 1% than that of the polymer of the core component is used for the sheath component. The heat resistance of the light-transmitting fiber is highly improved.

Claims

1. A light-transmitting fiber comprising a core component and a sheath component covering the core component, the core component consisting essentially of a polymer comprising 2% to 100% by weight of ring structure units represented by the following general formula (I):

##STR3## wherein R stands for a hydrogen atom or an aliphatic, alicyclic, or aromatic hydrocarbon group having 1 to 20 carbon atoms,

and 0% to 98% by weight of monomer units composed mainly of methyl methacrylate, and the sheath component being composed of a polymer having a refractive index smaller by at least 1% than that of the polymer of the core component.

2. A light-transmitting fiber as set forth in claim 1, wherein the core component contains at least 10% by weight of the ring structure units.

3. A light-transmitting fiber as set forth in claim 1, wherein the polymer of the core component is drawn by at least 10% after spinning.

4. A light-transmitting fiber as set forth in claim 1, wherein the polymer of the core component has a heat distortion temperature of at least 110°

C.

5. A light-transmitting fiber as set forth in claim 1, wherein its thermal shrinkage factor after 1 hour'"'"'s heat treatment at 130°

C. is smaller than 5%.

6. A light-transmitting fiber as set forth in claim 1, wherein R in the general formula (I) is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.

7. A light-transmitting fiber as set forth in claim 6, wherein the aliphatic hydrocarbon group is selected from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, and tert-butyl.

8. A light-transmitting fiber as set forth in claim 1, wherein R in the general formula (I) is an aromatic hydrocarbon group having 6 to 10 carbon atoms.

9. A light-transmitting fiber as set forth in claim 8, wherein the aromatic hydrocarbon group is selected from phenyl and substituted phenyl.