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EP-4739743-A1 - METHODS OF METALLIZING POLYPROPYLENE COMPOUNDS AND METALLIZED ARTICLES THEREOF

EP4739743A1EP 4739743 A1EP4739743 A1EP 4739743A1EP-4739743-A1

Abstract

Disclosed are methods that involve bonding a metal layer to thermoplastic that comprises (a) polypropylene and (b) one or more of the following polar polymers: polyvinylpyrrolidone, polypropyelene acrylic acid, polyethylene acrylic acid, poly(vinyl alcohol), ethylene vinyl alcohol, polypropylene acrylate, polyethylene acrylate, polypropylene methacrylate, polyethylene methacrylate, polyacrylic acid, polymethacrylic acid, polyacrylate, and polymethacrylate, wherein the percentage of polar groups in the one or more polar polymers is in a range of 5% to 100%. Also disclosed are articles comprising the metallized thermoplastic.

Inventors

  • NAYAK, Pradipta
  • VELATE, SURESH
  • DHANABALAN, ANANTHARAMAN
  • BATUBARA, Shahad H
  • MOIDEEN, Mohammed Ashraf

Assignees

  • SABIC Global Technologies B.V.

Dates

Publication Date
20260513
Application Date
20240703

Claims (15)

  1. 1. A method comprising: etching a surface of a thermoplastic that comprises (a) polypropylene and (b) one or more of the following polar polymers: polyvinylpyrrolidone, polypropylene acrylic acid, polyethylene acrylic acid, poly(vinyl alcohol), ethylene vinyl alcohol, polypropylene acrylate, polyethylene acrylate, polypropylene methacrylate, polyethylene methacrylate, polyacrylic acid, polymethacrylic acid, polyacrylate, and polymethacrylate, wherein the percentage of polar groups in the one or more polar polymers is in a range of 5% to 100%; and after etching the surface of the thermoplastic, bonding a metal layer to the thermoplastic.
  2. 2. The method of claim 1, wherein the thermoplastic comprises 0.5 wt. % to 30 wt. % of the one or more polar polymers.
  3. 3. The method of any of claims 1 and 2, wherein the thermoplastic comprises 5 wt. % to 40 wt.% of an inorganic additive.
  4. 4. The method of claim 3, wherein the inorganic additive comprises one or more of the following: aluminum oxide, zinc oxide, titanium dioxide, zirconium oxide, calcium carbonate, talc, silica, glass beads, hallow glass beads and glass fibers, aluminum oxide fibers, carbon fibers, and graphene.
  5. 5. The method of any of claims 1 to 4, wherein the thermoplastic comprises 30 wt. % to 95 wt. % polypropylene.
  6. 6. The method of any of claims 1 to 5, wherein etching the surface of the thermoplastic comprises etching a surface of the thermoplastic with an oxidizing agent.
  7. 7. The method of claim 6, wherein the oxidizing agent comprises any of hexachrome sulfuric acid (HCSA), tri-chrome, potassium permanganate, and manganese-based etching solutions, or a combination thereof.
  8. 8. The method of any of claims 6 and 7, wherein (i) the bonding is between the metal layer and the etched surface and (ii) the bonding is carried out by electroless plating or a combination of electroless plating and electroplating.
  9. 9. The method of any of claims 1 to 8, wherein the bond between the metal layer and the thermoplastic has a peel strength of 0.2 to 2 N/mm.
  10. 10. A metallized thermoplastic article comprising: a metal layer bonded to thermoplastic that comprises: (a) polypropylene; (b) an inorganic additive; and (c) one or more of the following polar polymers: polyvinylpyrrolidone, polypropylene acrylic acid, polyethylene acrylic acid, poly(vinyl alcohol), ethylene vinyl alcohol, polypropylene acrylate, polyethylene acrylate, polypropylene methacrylate, polyethylene methacrylate, polyacrylic acid, polymethacrylic acid, polyacrylate, and polymethacrylate, wherein the percentage of polar groups in the one or more polar polymers is in a range of 5% to 100%.
  11. 11. The article of claim 10, wherein the thermoplastic comprises 0.5 wt. % to 30 wt. % of the one or more polar polymers.
  12. 12. The article of any of claims 10 and 11, wherein the thermoplastic comprises 5 wt. % to 40 wt.% of the inorganic additive.
  13. 13. The article of claim 12, wherein the inorganic additive comprises one or more of the following: aluminum oxide, zinc oxide, titanium dioxide, zirconium oxide, calcium carbonate, talc, silica, glass beads, hallow glass beads and glass fibers, aluminum oxide fibers, carbon fibers, and graphene.
  14. 14. The article any of claims 10 to 13, wherein the thermoplastic comprises 30 wt. % to 95 wt.% polypropylene.
  15. 15. The article of any of claims 10 to 14, wherein the article is configured to be comprised in one or more of the following: an electrical or electronic device, a component of a telecommunication device, radio-frequency (RF) filter, EMI shielding, wave-guide, antenna substrate, frequency selective surface, components of appliances, packaging, automotive interior components, automotive exterior components, badges, trims, electrical vehicle battery cover, and thermal management component.

Description

METHODS OF METALLIZING POLYPROPYLENE COMPOUNDS AND METALLIZED ARTICLES THEREOF CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the benefit of priority from European Patent Application No. EP23183981 filed July 6, 2023, the disclosure of which is incorporated herein by reference in its entirety. FIELD [0002] The present disclosure generally relates to compounds that comprise propylene (polypropylene compounds). More specially, the present disclosure relates to metallizing polypropylene compounds and metallized articles thereof. BACKGROUND [0003] In recent years, manufacturers have increased the use of metallized plastic components in a variety of products. For example, metallized polymer components are used in electrical and electronic (E&E) devices, automotive equipment, computer body parts, office equipment, machinery, and packaging. Typically, metal deposition on plastic surfaces is accomplished by techniques such as electroless plating, electroplating, and the like. Key challenges in electroless plating of plastic’s polymer surface is creating a strong and durable adhesion between metal and the polymer, as they have properties that make them inherently incompatible with each other; for example, they have disparate surface energies and coefficient of thermal expansions (CTEs). Generally, to promote a strong adhesion of metal to a polymer surface, chemical and/or surface morphological changes have to be made to the surface of the polymer substrate. [0004] The conventional procedure used to make changes to the surface of the polymer substrate involves etching the polymer surface with strong oxidizing solutions such as hexachrome sulfuric acid or acidified potassium permanganate, prior to the electroless plating. This etching step results in (i) the formation of nano/micro-pores that allow the anchoring/nucleation of metal particles and/or the mechanical interlocking and/or (ii) the creation of polar groups such as hydroxyl, carbonyl, and carboxyl groups on the polymer surface. The efficiency of such etching step has been widely proven for certain thermoplastic polymers such as acrylonitrile-butadiene-styrene copolymer (ABS). In the ABS matrix, the butadiene (BD) domains are uniformly dispersed within the styrene acrylonitrile (SAN) in which the double bond of butadiene will get selectively etched with oxidizing agents leading to the formation of micro-cavities and polar groups. On the other hand, in the case of hydrophobic thermoplastic polymers such as polypropylene (PP), the above etching step is generally not effective. [0005] It appears that several approaches have been explored to improve the adhesion of metal onto polypropylene substrates. For example, pre-treatments such as flame treatment, corona discharge treatment, plasma treatment, grafting of glycidyl methacrylate, and grafting of maleic anhydride have been suggested to enhance the adhesion of metal onto substrate. Melt blending of chelating monomers such as methacrylate, maleimide, and metal-bonding groups in diketone and aspartic acid have also been used with polypropylene to functionalize the polymer and enhance the metal adhesion. Low polarity rubber, and homopolymer or copolymer ethylene, mineral additives and carbon black have also been used to enhance the adhesion of metal onto polypropylene. BRIEF SUMMARY [0006] There is a need for polypropylene compounds that are amenable to metallization with standard electroless plating and electroplating processes. The present thermoplastic polypropylene compounds are amenable to etching as a result of polar polymers included in them. [0007] Some configurations of the disclosure include a method that comprises bonding a metal layer to thermoplastic that comprises (a) polypropylene and (b) one or more of the following polar polymers (which can be copolymers): polyvinylpyrrolidone, polypropylene acrylic acid, polyethylene acrylic acid, poly(vinyl alcohol), ethylene vinyl alcohol, polypropylene acrylate, polyethylene acrylate, polypropylene methacrylate, polyethylene methacrylate, polyacrylic acid, polymethacrylic acid, polyacrylate, and polymethacrylate, wherein the percentage of polar groups in the one or more polar polymers is in a range of 5% to 100%. [0008] Some configurations of the disclosure include a method that comprises etching a surface of a thermoplastic that comprises (a) polypropylene and (b) one or more of the following polar polymers: polyvinylpyrrolidone, polypropylene acrylic acid, polyethylene acrylic acid, poly(vinyl alcohol), ethylene vinyl alcohol, polypropylene acrylate, polyethylene acrylate, polypropylene methacrylate, polyethylene methacrylate, polyacrylic acid, polymethacrylic acid, polyacrylate, and polymethacrylate, wherein the percentage of polar groups in the one or more polar polymers is in a range of 5% to 100%; and after etching the surface of the thermoplastic, bonding a metal layer to the thermoplastic. [0009] Some configurations of