Ion implantation of plastics

• US 4,743,493 A
• Filed: 10/06/1986
• Issued: 05/10/1988
• Est. Priority Date: 10/06/1986
• Status: Expired due to Term

• Current Assignee: Spire Corporation A Corporation MA
• Original Assignee: Spire Corporation
• Inventors: Sioshansi, Piran, Oliver, Richard W.
• Primary Examiner(s): Ives, P. C.
• Application Number:
  US06/915,414
• Time in Patent Office: 582 Days
• Field of Search: 428/412, 428/696, 428/421, 428/217, 428/522, 428/523, 427/38
• US Class Current: 428/217
• CPC Class Codes: B29C 2035/0872 using ion-radiation, e.g. alpha-rays
• CPC Class Codes: B29C 59/14 by plasma treatment plasma tubes per se H01J
• CPC Class Codes: B29C 59/16 by wave energy or particle radiation , e.g. infrared heating B29C59/007 takes precedence
• CPC Class Codes: B29D 11/00 Producing optical elements, e.g. lenses or prisms grinding or polishing of optical elements B24B; constructional form of optical elements G02B; optical parts of spectacles G02C7/00
• CPC Class Codes: B29K 2023/0683 UHMWPE, i.e. ultra high molecular weight polyethylene
• CPC Class Codes: B29K 2033/08 Polymers of acrylic acid esters, e.g. PMA, i.e. polymethylacrylate
• CPC Class Codes: B29K 2069/00 Use of PC, i.e. polycarbonates or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2995/0058 Inert to chemical degradation
• CPC Class Codes: B29K 2995/007 Hardness
• CPC Class Codes: B29L 2011/00 Optical elements, e.g. lenses, prisms
• CPC Class Codes: Y10T 428/24983 Hardness
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/3154 Of fluorinated addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31935 Ester, halide or nitrile of addition polymer
• CPC Class Codes: Y10T 428/31938 Polymer of monoethylenically unsaturated hydrocarbon

Abstract

An ion implantation process for plastics is disclosed which materially enhances their surface hardness and their resistance to chemical attack. The plastics include the polycarbonates, the acrylics and their combinations, and ultra high molecular weight polyethylenes. The plastics are ion implanted by energetic ions such as aluminum, magnesium, silicon, titanium, yttrium, fluorine and chlorine ions. Such ion implanted plastics, in their transparent form, find uses such as aircraft, spacecraft, auto transparencies, lenses for safety and eyeglasses and contact lenses, face and gas masks and the like. In their non-transparent form, the ion implanted plastics are useful as ball bearings, safety helmets, floor coverings, appliance and auto moldings and the like.

Claims

1. An inflexible plastic material with improved surface characteristics, including increased surface hardness and increased surface resistance to chemical attack, comprising:

(a) a layer formed of said inflexible plastic material of one of a group of plastic materials comprising the polycarbonates, the acrylics, a combination of polycarbonates and acrylics, and ultra high molecular weight polyethylenes;

(b) said layer composed of at least two integral stratums;

a thin stratum and a thick stratum contiguous therewith, wherein said thin stratum has a thickness from about 0.1 to about 5 micrometers;

(c) said thin stratum being ion implanted with an ion beam of energetic ions, wherein said implanted ions within said thin stratum impart to said layer said increased surface hardness and said increased surface chemical resistance;

said implanted ions comprising aluminum, magnesium, silicon, titanium, yttrium, fluorine and chlorine ions.

2. The plastic material of claim 1 which is transparent.

3. The plastic material of claim 1 wherein the surface of said thin stratum is hydrophobic, and wherein said thin stratum has increased density of material, and wherein said hydrophobic surface possesses decreased surface energy.

4. The plastic material of claim 1 wherein said implanted ions within said thin stratum cause radiation damage so as to crosslink with certain of the polymer chains of said plastic material.

5. The plastic material of claim 1 wherein said implanted ions react with the polymer chains of said inflexible plastic material and form precipitate chemical compounds, said precipitate chemical compounds including:

Al₂ O₃, TiO₂, Y₂ O₃, MgO, SiO₂, and fluorinated and chlorinated hydrocarbons.