Metal coating process

• US 4,101,356 A
• Filed: 10/25/1977
• Issued: 07/18/1978
• Est. Priority Date: 11/05/1976
• Status: Expired due to Term

• Current Assignee: Progress Processing Limited
• Original Assignee: Progress Processing Limited
• Inventors: Savelkouls, Leonardus Joseph
• Primary Examiner(s): Drummond, Douglas J.
• Application Number:
  US05/844,525
• Time in Patent Office: 266 Days
• Field of Search: 156/272, 156/380, 156/71
• US Class Current: 156/71
• CPC Class Codes: B29C 35/08 by wave energy or particle radiation B29C64/00, B29C71/04 take precedence
• CPC Class Codes: B29C 63/0004 Component parts, details or accessories; Auxiliary operations
• CPC Class Codes: B29C 63/0065 Heat treatment
• CPC Class Codes: B29C 63/0069 of tubular articles
• CPC Class Codes: B29C 63/02 using sheet or web-like material B29C63/26 and B29C63/38 take precedence
• CPC Class Codes: B29C 63/065 continuously
• CPC Class Codes: B29C 63/10 around tubular articles
• CPC Class Codes: B29C 63/343 the tubular sheathing having a deformed non-circular cross-section prior to introduction
• CPC Class Codes: B29C 65/02 by heating, with or without pressure
• CPC Class Codes: B29C 65/46 heated by induction
• CPC Class Codes: B29C 65/4815 Hot melt adhesives, e.g. thermoplastic adhesives
• CPC Class Codes: B29C 66/1122 Single lap to lap joints, i.e. overlap joints B29C66/45, B29C66/472, B29C66/52272 take precedence
• CPC Class Codes: B29C 66/4322 by joining a single sheet to itself B29C66/4332 takes precedence
• CPC Class Codes: B29C 66/45 Joining of substantially the whole surface of the articles methods or apparatus for laminating B32B37/00
• CPC Class Codes: B29C 66/49 Internally supporting the, e.g. tubular, article during joining B29C66/63 takes precedence
• CPC Class Codes: B29C 66/53261 Enclosing tubular articles between substantially flat elements
• CPC Class Codes: B29C 66/71 characterised by the composition of the plastics material of the parts to be joined welding bar compositions B29C65/125
• CPC Class Codes: B29C 66/74283 Iron or alloys of iron, e.g. steel
• CPC Class Codes: B29C 66/8126 characterised by the intensive physical properties or by the optical properties of the material constituting the pressing elements, e.g. constituting the welding jaws or clamps
• CPC Class Codes: B29C 66/8161 said pressing elements being supported or backed-up by springs or by resilient material
• CPC Class Codes: B29C 66/8221 : Scissor or lever mechanisms, i.e. involving a pivot point
• CPC Class Codes: B29C 66/83411 : Roller, cylinder or drum types B29C66/83431 takes precedence; rollers, cylinders or drums moving relative to and tangentially to the parts to be joined B29C66/8362
• CPC Class Codes: B29C 66/83413 : cooperating rollers, cylinders or drums
• CPC Class Codes: B29C 66/8362 : Rollers, cylinders or drums moving relative to and tangentially to the parts to be joined
• CPC Class Codes: B29C 66/8612 : Ironing tool type
• CPC Class Codes: B29K 2023/00 : Use of polyalkenes or derivatives thereof as moulding material
• CPC Class Codes: B29K 2023/06 : PE, i.e. polyethylene
• CPC Class Codes: B29K 2027/06 : PVC, i.e. polyvinylchloride
• CPC Class Codes: B29K 2027/18 : PTFE, i.e. polytetrafluorethene , e.g. ePTFE, i.e. expanded polytetrafluorethene
• CPC Class Codes: B29K 2077/00 : Use of PA, i.e. polyamides, e.g. polyesteramides or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2705/00 : Use of metals, their alloys or their compounds, for preformed parts, e.g. for inserts
• CPC Class Codes: B29K 2995/0008 : Magnetic or paramagnetic
• CPC Class Codes: B29L 2009/003 : comprising a metal layer
• CPC Class Codes: B32B 1/08 : Tubular products
• CPC Class Codes: B32B 15/02 : Layer formed of wires, e.g. mesh
• CPC Class Codes: B32B 15/08 : of synthetic resin
• CPC Class Codes: B32B 15/20 : comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2307/714 : Inert, i.e. inert to chemical degradation, corrosion
• CPC Class Codes: B32B 38/0008 : Electrical discharge treatment, e.g. corona, plasma treatment; wave energy or particle radiation heat treatment B32B38/0036
• CPC Class Codes: B32B 7/04 : Interconnection of layers
• CPC Class Codes: B32B 7/12 : using interposed adhesives or interposed materials with bonding properties

Abstract

Metal substrates, such as steel sheeting or steel plates of large containers and similar structures, are coated in a continuous operation by arranging a polymer stratum that comprises a heat or melt bonding composition in contact with the metal substrate and by directing electromagnetic radiation in the radio frequency range through the polymer stratum without substantially heating the latter onto the substrate for briefly heating a surface area of the substrate to a temperature where the heat or melt bonding composition in contact with the substrate is activated to form a heat or melt bonded connection between the polymer stratum and the metal substrate. The heated surface area is moved continuously so as to bondingly coat the surface of the substrate, e.g. the fuel-receiving compartments of a tanker, with the polymer stratum. An apparatus for the coating process is disclosed and comprises an inductor loop for directing radio-frequency radiation through the polymer stratum onto the metal substrate. The inductor loop can be made to conform with the surface of the substrate that is to be coated and made resistant against corrosion.

Claims

1. In the process of coating a metal substrate with a substantially uniform layer of an organic polymer composition by providing a polymer stratum including a heat or melt bonding polymer composition in a contacting relation with said metal substrate, subjecting said metal substrate to electromagnetic radiation capable of heating said substrate for activation of said melt bonding composition, and allowing said metal substrate to cool so as to form a strong interbonding connection between said heat or melt bonding composition and said metal substrate;

the improvement consisting of moving a source of electromagnetic radiation having a frequency in the radio frequency range relative to and over said polymer stratum near a surface thereof that is not in contact with said metal substrate for directing said radiation through said polymer stratum without heating thereof and onto said metal substrate in an area where said metal substrate is in said contacting relation with said polymer stratum and for briefly heating a surface portion of said metal substrate in said area by said radiation to a temperature at which said heat or melt bonding composition is capable of forming said interbonding connection, and continuously displacing said area by said movement of said source of said electromagnetic radiation relative to said substrate.

2. The process of claim 1, wherein said radiation has a frequency in the range of about 200 kilocycles per second to about 800 kilocycles per second.

3. The process of claim 1, wherein said source of said electromagnetic radiation is en elongated inductor loop shaped to substantially conform with said surface portion of said metal substrate.

4. The process of claim 3, wherein said elongated inductor loop is flexible.

5. The process of claim 3, wherein said inductor is operated with a power input of at least about 25 kilowatt per meter of the length of said inductor loop and wherein said frequency is in the range of from about 200 kilocycles per second to about 800 kilocycles per second.

6. The process of claim 1, wherein said polymer stratum including said heat or melt bonding composition is a normally flexible material having a layer of said heat or melt bonding composition and a layer of a second polymer composition.

7. The process of claim 6, wherein said second polymer composition is an olefinic polymer composition.

8. The process of claim 6, wherein said heat or melt bonding composition comprises a polymer selected from the group consisting of synthetic organic homopolymers and copolymers having recurring carboxylic groups in the molecular chain of said polymer.

9. The process of claim 6, wherein said source of said electromagnetic radiation is continuously moved relative to said stratum in physical contact with said second layer thereof so as to press said stratum onto said metal substrate.

10. The process of claim 3, wherein said metal substrate is a substantially continuous surface of a steel structure and wherein elongated web portions of said polymer stratum are laid onto said continuous surface for substantially covering the latter, said elongated inductor loop being moved over said elongated web portions as they are laid onto said continuous surface, and said elongated inductor loop extending transversely to and over the edges of each of said elongated web portions.

11. The process of claim 2, wherein said melt bonding composition is applied onto said metal substrate as a substantially continuous solid layer and wherein said elongated inductor loop is continuously moved relative to and over said solid layer in a contacting relation therewith.

12. The process of claim 4, wherein said elongated flexible inductor loop comprises a radiation-emitting flexible metallic conductor and a flexible non-metallic liquid-impervious tube forming at least one conduit for a fluid coolant that is substantially non-attenuating for said electromagnetic radiation when said non-metallic flexible tube surrounds said flexible metallic conductor.

13. In a process of producing a corrosion resistant coating on a structure having continuous steel surfaces by coating said surfaces with a substantially uniform layer of an organic polymer composition;

the improvement consisting of arranging a polymer stratum including a heat or melt bonding polymer composition in a contacting relation with said surface;

continuously moving a radio frequency emitter over said stratum for directing radio frequency radiation through said stratum and activating said heat or melt bonding polymer composition by means of heat produced by said radiation in an interface portion between said steel surface and said stratum.