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US-20260125574-A1 - COATINGS

US20260125574A1US 20260125574 A1US20260125574 A1US 20260125574A1US-20260125574-A1

Abstract

The present invention provides an electronic or electrical device or component thereof comprising a cross-linked polymeric coating on a surface of the electronic or electrical device or component thereof; wherein the cross-linked polymeric coating is obtainable by exposing the electronic or electrical device or component thereof to a plasma comprising a monomer compound and a crosslinking reagent for a period of time sufficient to allow formation of the cross-linked polymeric coating on a surface thereof.

Inventors

  • Stephen Richard Coulson
  • Delwyn EVANS
  • Angeliki SIOKOU
  • Clive Telford

Assignees

  • P2I LTD

Dates

Publication Date
20260507
Application Date
20251219
Priority Date
20150609

Claims (20)

  1. 1 - 20 . (canceled)
  2. 21 . An electronic device, electrical device, or component thereof comprising a protective cross-linked polymeric coating on a surface of the electronic device, electrical device, or component thereof; wherein the protective cross-linked polymeric coating is obtained by exposing the electronic or electrical device or component thereof to a plasma comprising a monomer compound and a crosslinking reagent for a period of time sufficient to allow formation of the protective cross-linked polymeric coating on a surface thereof, wherein the monomer compound has the following formula: where R 1 , R 2 , and R 4 are each independently selected from hydrogen, optionally substituted branched or straight chain C 1 -C 6 alkyl or halo alkyl or aryl optionally substituted by halo, and R 3 is selected from: where each X is independently selected from hydrogen, a halogen, optionally substituted branched or straight chain C 1 -C 6 alkyl, halo alkyl or aryl optionally substituted by halo; where A is alicyclic optionally substituted by halo; and n 1 is an integer from 0 to 27; and wherein the crosslinking reagent comprises two or more unsaturated bonds attached by means of one or more linker moieties and has a boiling point of less than 500° C. at standard pressure.
  3. 22 . The electronic device, electrical device, or component thereof according to claim 21 , wherein the protective cross-linked polymeric coating is a physical barrier to mass and electron transport.
  4. 23 . The electronic device, electrical device, or component thereof according to claim 21 , wherein the protective cross-linked polymeric coating forms a liquid repellent surface defined by a static water contact angle (WCA) of at least 90°.
  5. 24 . The electronic device, electrical device, or component thereof according to claim 21 , wherein the crosslinking reagent has one of the following structures: where Y 1 , Y 2 , Y 3 , Y 4 , Y 5 , Y 6 , Y 7 and Y 8 are each independently selected from hydrogen, optionally substituted cyclic, branched or straight chain C 1 -C 6 alkyl or aryl; and L is a linker moiety.
  6. 25 . The electronic device, electrical device, or component thereof according to claim 24 , wherein for compound (i) L has the following formula: each Y 9 is independently selected from, a bond, —O—, —O—C(O)—, —C(O)—O—, —Y 11 —O—C(O)—, —C(O)—O—Y 11 —, —OY 11 —, and —Y 11 O—, where Y 11 is an optionally substituted cyclic, branched or straight chain C 1 -C 8 alkylene; and Y 10 is selected from optionally substituted cyclic, branched or straight chain C 1 -C 8 alkylene and a siloxane group.
  7. 26 . The electronic device, electrical device, or component thereof according to claim 25 , wherein for compound (i) L has one of the following structures:
  8. 27 . The electronic device, electrical device, or component thereof according to claim 25 , wherein for compound (i) L has one of the following structures:
  9. 28 . The electronic device, electrical device, or component thereof according to claim 25 , wherein Y 10 has the following formula: wherein each Y 12 and Y 13 is independently selected from H, halo, optionally substituted cyclic, branched or straight chain alkyl, or —OY 14 , where Y 14 is selected from optionally substituted branched or straight chain C 1 -C 8 alkyl or alkenyl, and n is an integer from 1 to 10.
  10. 29 . The electronic device, electrical device, or component thereof according to claim 28 , wherein each Y 12 is H and each Y 13 is H.
  11. 30 . The electronic device, electrical device, or component thereof according to claim 29 , wherein n is from 4 to 6.
  12. 31 . The electronic device, electrical device, or component thereof according to claim 25 , wherein Y 10 has the following formula: wherein each Y 15 is independently selected from optionally substituted branched or straight chain C 1 -C 6 alkyl.
  13. 32 . The electronic device, electrical device, or component thereof according to claim 31 , wherein each Y 15 is methyl, and each Y 9 is a bond.
  14. 33 . The electronic device, electrical device, or component thereof according to claim 25 , wherein Y 10 has the following formula: wherein Y 16 to Y 19 are each independently selected from H and optionally substituted branched or straight chain C 1 -C 8 alkyl or alkenyl.
  15. 34 . The electronic device, electrical device, or component thereof according to claim 33 , wherein Y 18 is H or vinylene, and Y 16 , Y 17 and Y 19 are each H.
  16. 35 . The electronic device, electrical device, or component thereof according to claim 21 wherein the crosslinking reagent is selected from divinyl adipate (DVA), 1,4-butanediol divinyl ether (BDVE), 1,4-cyclohexanedimethanol divinyl ether (CDDE), 1,7-octadiene (17OD), 1,2,4-trivinylcyclohexane (TVCH), 1,3-vivinyltetramethyldisiloxane (DVTMDS), diallyl 1,4-cyclohexanedicarboxylate (DCHD), 1,6-divinylperfluorohexane (DVPFH), 1H,1H,6H,6H-perfluorohexanediol diacrylate (PFHDA) and glyoxal bis (diallyl acetal) (GBDA).
  17. 36 . The electronic device, electrical device, or component thereof according to claim 24 , wherein for compound (ii), L is selected from a branched or straight chain C 1 -C 8 alkylene or an ether group.
  18. 37 . The electronic device, electrical device, or component thereof according to claim 21 wherein each X is H.
  19. 38 . The electronic device, electrical device, or component thereof according to claim 21 , wherein each X is F.
  20. 39 . The electronic device, electrical device, or component thereof according to claim 21 , wherein the electronic device, electrical device, or component thereof is selected from mobile phones, smartphones, pagers, radios, sound and audio systems such as loudspeakers, microphones, ringers and/or buzzers, hearing aids, personal audio equipment such as personal CD, tape cassette or MP3 players, televisions, DVD players including portable DVD players, video recorders, digi and other set-top boxes, computers and related components such as laptop, notebook, tablet, phablet or palmtop computers, personal digital assistants (PDAs), keyboards, or instrumentation, games consoles, data storage devices, outdoor lighting systems, radio antennae and other forms of communication equipment, and printed circuit boards.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a continuation of U.S. application Ser. No. 17/219,388, filed Mar. 31, 2021; which is a continuation of U.S. application Ser. No. 16/547,728 filed Aug. 22, 2019, now U.S. Pat. No. 11,041,087; which is a continuation of U.S. application Ser. No. 15/735,130, filed Dec. 8, 2017, now U.S. Pat. No. 10,421,876, which is a U.S. national stage filing of Patent Cooperation Treaty (PCT) Application No. PCT/GB2016/051688, filed on Jun. 8, 2016; which claims the benefit of European Application No. 15386017.6, filed Jun. 9, 2015, wherein the entirety of each of said patent applications is incorporated herein by reference. FIELD OF THE INVENTION This invention relates to protective coatings. Specifically, the present invention relates to protective coatings for electronic or electrical devices and components thereof, and methods of forming such coatings. The coatings can protect by being hydrophobic and so resist the ingress of water-based liquid into electronic devices, or they can protect by forming a barrier coating and so provide electrical resistance between the electrical parts of the phone and water based liquid. BACKGROUND OF THE INVENTION Monounsaturated monomers are used to make barrier coatings using plasma polymerisation processes (see co-pending application). The perfluoroalkyl chain monomers are also used for generating hydrophobic surfaces from pulsed plasma deposition processes (see WO 9858117 A1). The power of the plasma initiated polymerisation affects the nature of the polymer produced. The higher average energy inputs of continuous wave plasmas lead to more fragmentation of the monomer, and so the polymer loses structural properties of the monomer. In the case of 1H, 1H,2H,2H-perfluorodecyl acrylate (PFAC8), there's less retention of the perfluoroalkyl chain and the contact angle of the surface coating is compromised. Higher plasma energies also lead to more crosslinking. For the lower average energy inputs of pulsed plasmas, there's better retention of monomer structure and less crosslinking. The greater retention of the perfluoro chain under low energy, pulsed plasma conditions leads to best levels of contact angles for the surface coating. When the perfluoroalkyl chains have eight or more fluorinated carbons (long chain), the polymer made from the monomer has a crystalline structure. When the perfluoroalkyl chains have less than eight fluorinated carbons, the resulting polymer is amorphous and so can be unstable in the presence of water (see “Molecular Aggregation Structure and Surface Properties of Poly(fluoroalkyl acrylate) Thin Films, Marcomolecules, 2005, vol 38, p 5699-5705) When long chain perfluoroalkyl polymers are produced by high average power (continuous wave or CW) or low average power (pulsed wave or PW) plasmas, then because of the crystalline structure of the long chains, the polymers are non-stick to the touch and stable in the presence of water. However, the feel and water stability of shorter chain polymer coatings is affected by the plasma power levels used. For example, when PFAC6 (1H,1H,2H,2H-perfluorooctyl acrylate) is polymerised in low power plasma conditions, the resulting polymer coating can have several disadvantages. For example the coating can cause water drops to spread out a little (slump), be marked by the presence of a water drop on its surface, have a tacky feel, or can be easily smeared (for example on substrates of silicon wafer and ABS plastic). By increasing the power of the plasma used for polymerisation, the polymer becomes more crosslinked and becomes more resistant to smearing. However, increasing the power has the concomitant effect of decreasing the water contact angle through more monomer fragmentation (as described above). FIG. 1 shows the effect of increasing the power to monomer flow ratio for CW plasmas in a 125 litre chamber: at a ratio of 4 W/μl/min, the water contact angle is ˜85-95 degrees and the coating is tack-free. However, as the ratio drops, the contact angle increases and the occurrence of tacky/smudgy coatings increases too. FIG. 2 shows the same effect for pulsed plasma conditions. These results show that the process window for producing tack and smudge-free coatings have a limited plasma processing range and the final coating has a compromised water contact angle. Accordingly, it is an aim to solve one or more of the above-mentioned problems with the prior art coatings. STATEMENT OF INVENTION An aspect of the present invention provides an electronic or electrical device or component thereof comprising a protective cross-linked polymeric coating on a surface of the electronic or electrical device or component thereof; wherein the protective cross-linked polymeric coating is obtainable by exposing the electronic or electrical device or component thereof to a plasma comprising a monomer compound and a crosslinking reagent for a period of time sufficient to allow formation of the