U.S. patent application number 16/131368 was filed with the patent office on 2019-01-10 for coated electrical or electronic device protected from liquid penetration.
This patent application is currently assigned to P2i Limited. The applicant listed for this patent is P2i Limited. Invention is credited to Stephen Coulson.
Application Number | 20190010351 16/131368 |
Document ID | / |
Family ID | 36010616 |
Filed Date | 2019-01-10 |
![](/patent/app/20190010351/US20190010351A1-20190110-C00001.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00002.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00003.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00004.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00005.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00006.png)
![](/patent/app/20190010351/US20190010351A1-20190110-C00007.png)
United States Patent
Application |
20190010351 |
Kind Code |
A1 |
Coulson; Stephen |
January 10, 2019 |
COATED ELECTRICAL OR ELECTRONIC DEVICE PROTECTED FROM LIQUID
PENETRATION
Abstract
An electrical or electronic device comprising a polymeric
coating, formed by exposing;the device to pulsed plasma comprising
a compound of formula (I), ##STR00001## where R.sup.1, R.sup.2,
R.sup.3 and R.sup.4 are as defined in the specification, for a
sufficient period of time to allow a polymeric layer to form on the
surface of the electrical or electronic device. Devices of this
type are protected from contamination by liquids, in particular
environmental liquids.
Inventors: |
Coulson; Stephen; (Abingdon,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
P2i Limited |
Abingdon |
|
GB |
|
|
Assignee: |
P2i Limited
Abingdon
GB
|
Family ID: |
36010616 |
Appl. No.: |
16/131368 |
Filed: |
September 14, 2018 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
15443114 |
Feb 27, 2017 |
|
|
|
16131368 |
|
|
|
|
12161181 |
Sep 12, 2008 |
9617353 |
|
|
PCT/GB2007/000149 |
Jan 19, 2007 |
|
|
|
15443114 |
|
|
|
|
60762242 |
Jan 26, 2006 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08F 220/24 20130101;
C09D 4/00 20130101; C09D 133/16 20130101; B05D 1/62 20130101; B05D
5/00 20130101; C09D 5/00 20130101; B05D 5/083 20130101; C08F 2/52
20130101 |
International
Class: |
C09D 133/16 20060101
C09D133/16; C09D 4/00 20060101 C09D004/00; C08F 220/24 20060101
C08F220/24; B05D 5/08 20060101 B05D005/08; C08F 2/52 20060101
C08F002/52; C09D 5/00 20060101 C09D005/00; B05D 5/00 20060101
B05D005/00; B05D 1/00 20060101 B05D001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 20, 2006 |
GB |
0601117.5 |
Claims
1. An electrical or electronic device having a polymeric coating,
formed by exposing said device to pulsed plasma comprising a
compound of formula (I) ##STR00006## where R.sup.1, R.sup.2 and
R.sup.3 independently are selected from hydrogen, alkyl, haloalkyl
or aryl optionally substituted by halo; and R.sup.4 is a group
X--R.sup.5 where R.sup.5 is an alkyl or haloalkyl group and X is a
bond; a group of formula --C(O)O(CH.sub.2).sub.nY-- where n is an
integer of 1 to 10 and Y is a bond or a sulphonamide group; or a
group --(O).sub.pR.sup.6(O).sub.q(CH.sub.2).sub.t-- where R.sup.6
is aryl optionally substituted by halo, p is 0 or 1, q is 0 or 1
and t is 0 or an integer of 1 to 10, provided that where q is 1, t
is other than 0, for a sufficient period of time to allow a
protective polymeric layer to form on the surface of the electrical
or electronic device.
2. An electrical or electronic device according to claim 1, which
is selected from communications devices, sound or audio systems
devices, computers or computer-related components, outdoor lighting
systems, or electrical or electronic devices used in transport
vehicles, washing machines and dishwashers; or components of any of
these.
3. An electrical or electronic device according to claim 2, which
is a sound or audio system device.
4. An electrical or electronic device according to claim 3, which
is a loudspeaker, microphone, ringer or buzzer.
5. An electrical or electronic device according to claim 4
comprising a microphone that comprises a foamed plastic cover and
the polymeric layer is present thereon.
6. An electrical or electronic device according to claim 1, wherein
any alkyl chains in R.sup.1, R.sup.2 or R.sup.3, have 1 to 6 carbon
atoms.
7. An electrical or electronic device according to claim 1, wherein
at least one of R.sup.1, R.sup.2 and R.sup.3 is hydrogen.
8. An electrical or electronic device according to claim 1, wherein
R.sup.3 is an alkyl group such as methyl or propyl.
9. An electrical or electronic device according to claim 1, wherein
the compound of formula (I) is a compound of formula (II)
CH.sub.2.dbd.CH--R.sup.5 (II) where R.sup.5 is as defined in claim
1, or a compound of formula (III)
CH.sub.2.dbd.CR.sup.7C(O)O(CH.sub.2).sub.nR.sup.5 (III) where n and
R.sup.5 are as defined in claim 1 and R.sup.7 is hydrogen,
C.sub.1-10 alkyl, or C.sub.1-10haloalkyl.
10. An electrical or electronic device according to claim 1,
wherein R.sup.5 comprises an alkyl group having in the range of 6
to 12 carbon atoms.
11. An electrical or electronic device according to claim 1,
wherein R.sup.5 comprises a perfluoroalkyl group of formula
C.sub.mF.sub.2m+1 where m is an integer of 1 or more, preferably
1-20, and more preferably 4-12 such as 4, 6 or 8.
12. An electrical or electronic device according to claim 9,
wherein the compound of formula (III) is a compound of formula (IV)
##STR00007## where R.sup.7 is as defined in claim 9, and x is an
integer of 1 to 9.
13. An electrical or electronic device according to claim 12,
wherein the compound of formula (IV) is
1H,1H,2H,2H-heptadecafluorodecyl acrylate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is continuation of U.S. application Ser.
No. 15/443,114, filed Feb. 27, 2017, which is a division of U.S.
application Ser. No. 12/161,181, filed Nov. 12, 2008, which issued
as U.S. Pat. No. 9,617,353 on Apr. 11, 2017, which is a U.S.
national stage application under 35 U.S.C. .sctn. 371 of
PCT/GB2007/000149, filed Jan. 19, 2007, which claims priority of
United Kingdom application 0601117.5, filed Jan. 20, 2006 and U.S.
provisional application 60/762,242, filed Jan. 26, 2006, each of
the foregoing of which is incorporated by reference in its
entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to novel products in the form
of electronic or electrical devices, which are treated to protect
them from liquid damage, for example from environmental damage in
particular from water or other liquids, as well as to processes for
their production.
Description of Related Art
[0003] It is well known that electronic and electrical devices are
very sensitive to damage caused by contamination by liquids such as
environmental liquids, in particular water. Contact with liquids,
either in the course of normal use or as a result of accidental
exposure, can lead to short circuiting between electronic
components, and irreparable damage to circuit boards, electronic
chips etc.
[0004] The problem is particularly acute in relation to small
portable electronic equipment such as mobile phones, pagers,
radios, hearing aids, laptop, notebook, palmtop computers and
personal, digital assistants (PDAs), which can be exposed to
significant liquid contamination when moved outside. In addition,
they are prone to accidental exposure to liquids, for example if
dropped or splashed.
[0005] In addition, other types of electronic or electrical devices
are particularly prone to for example, environmental damage because
of their location, for example outdoor lighting systems, radio
antenna and other forms of communication equipment.
[0006] However, most devices of this type are damaged by accidental
spillage or the like. Particular examples may include desktop
devices such as keyboards, or instrumentation for instance used in
control rooms.
[0007] A particular problem arises in relation to devices which are
used in sound reproduction and which utilise transducers such as
loudspeakers, microphones, ringers and buzzers. These are
particularly susceptible to damage by liquid contamination, either
as a result of accidental exposure or from environmental factors
such as rain or spray in use. In many cases, the membranes or
diaphragms used in the devices, particularly the most economical
ones, are liquid absorbent to some degree, and when exposed to
water for example, will absorb considerable amounts. This affects
the operability of the transducer significantly and the quality of
the sound reproduction therefore suffers.
[0008] Many microphones are provided with an open-pore foamed
plastic enclosure surrounding the transducer. However, these must
be gas permeable and they do not provide complete protection
against liquid contamination.
[0009] In the past, this problem has been addressed by introducing
further water protective measures in the microphones. In many
cases, these comprise water-impermeable porous membranes such as
polytetrafluoroethylene (PTFE) membranes (see for example
WO/01/03468 or U.S. Pat. No. 5,420,570) into the device. In all
cases, these membranes will reduce the sensitivity of the
transducer and therefore have an adverse impact on sound
quality.
[0010] In other cases, such as that described in GB 2,364,463, more
rigid protective covers are provided, which are solid and holes
into which pick-up devices are inserted. This solution is costly
and complex and only suitable in certain limited situations.
[0011] Plasma deposition techniques have been quite widely used for
the deposition of polymeric coatings onto a range of surfaces, and
in particular onto fabric surfaces. This technique is recognised as
being a clean, dry technique that generates little waste compared
to conventional wet chemical methods. Using this method, plasmas
are generated from organic molecules, which are subjected to an
electrical field. When this is done in the presence of a substrate,
the radicals of the compound in the plasma polymerise on the
substrate. Conventional polymer synthesis tends to produce
structures containing repeat units that bear a strong resemblance
to the monomer species, whereas a polymer network generated using a
plasma can be extremely complex. The properties of the resultant
coating can depend upon the nature of the substrate as well as the
nature of the monomer used and conditions under which it is
deposited.
BRIEF SUMMARY OF THE INVENTION
[0012] The applicants have found that by utilising a specific type
of monomer under particular deposition conditions, electronic or
electrical devices having highly liquid repellent nano-coatings
thereon can be produced, which does not affect the efficacy of the
device.
DETAILED DESCRIPTION OF THE INVENTION
[0013] According to the present invention there is provided an
electronic or electrical device having a polymeric coating, formed
by exposing said device to pulsed plasma comprising a compound of
formula (I)
##STR00002##
[0014] where R.sup.1, R.sup.2 and R.sup.3 are independently
selected from hydrogen, alkyl, haloalkyl or aryl optionally
substituted by halo; and R.sup.4 is a group X--R.sup.5 where
R.sup.5 is an alkyl or haloalkyl group and X is a bond; a group of
formula --C(O)O(CH.sub.2).sub.nY-- where n is an integer of from 1
to 10 and Y is a bond or a sulphonamide group; or a group
--(O).sub.PR.sup.6(O).sub.q(CH.sub.2).sub.t-- where R.sup.6 is aryl
optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0
or an integer of from 1 to 10, provided that where q is 1, I is
other than 0, for a sufficient period of time to allow a protective
polymeric layer to form on the surface of the electrical or
electronic device.
[0015] As used herein, the expression "in a gaseous state" refers
to gases or vapours, either alone or in mixture, as well as
aerosols.
[0016] The expression "protective polymeric layer" refers to
polymeric layers which provide some protection against liquid
damage, and in particular are liquid (such as oil- and water-)
repellent. Sources of liquids from which the devices are protected
include environmental liquids such as water, and in particular
rain, as well as any other oil or liquid, which may be accidentally
spilled.
[0017] As used herein, the term "electronic or electrical device"
refers includes any piece of electrical or electronic equipment
which may be used, as well as components thereof such as printed
circuit boards (PCBs), transistors, resistors, electronic
components or semi-conductor chips. In particular however, the
coating is applied to the outer surface of a fully assembled
device, for example the fully assembled mobile phone, or
microphone. In such cases, the polymer layer will be applied to,
for example an outer casing or foam cover, as well as any exposed
components such as control buttons or switches, so as to prevent
any liquid reaching the components within.
[0018] The applicants have found that the polymer layer forms
across the entire surface of the device, including where the device
includes different substrate materials, such as a combination of
different plastics (including foamed plastic), metals and/or glass
surfaces, and surprisingly therefore, the entire device is made
liquid repellent. Even where these are not in a water-tight
relationship, for example push buttons on a mobile phone which are
not fused to the surrounding casing, the polymer layer deposited in
this way is sufficiently repellent to prevent liquids penetrating
the device around the edge of the buttons into the device. Thus it
has been found that mobile phones for example, which are generally
very sensitive to liquid damage, can be fully immersed in water
after the treatment of the invention, without any lasting harm.
[0019] As the coating is carried out without requiring immersion in
any liquids,there is no risk to the operations of the device as a
result of exposure to this procedure.
[0020] This broad applicability makes the present procedure
particularly advantageous.
[0021] Particular examples of electrical and electronic devices
include communications devices such as mobile phones and pagers,
radios, and sound and audio systems such as loudspeakers,
microphones, ringers 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 such as Sky, computers and
related components such as laptop, notebook or palmtop computers,
personal digital assistants (PDAs), keyboards, or instrumentation,
games consoles in particular hand-held playstations and the like,
or outdoor lighting systems.
[0022] Other particular examples may include electrical or
electronic components which are particularly at risk of water
contamination, such as those used in transport vehicles include
aircraft and other transport equipment such as trains, automobiles
in addition to other vehicles such as those used by the Military,
and other devices such as washing machines and dishwashers.
[0023] In a particular embodiment, the electronic or electrical
device is a microphone. By utilising the method defined above,
highly advantageous microphones have been produced. In particular,
the main features and benefits of using this approach are that by
coating for example the casing in particular the foam cover of the
microphone, the transducer is protected from liquid contamination
without any loss of sound quality. Levels of protection equal to or
better than those achieved using membranes are achieved without any
resultant "muffling" of the sound quality, which is a feature of
the use of such membranes.
[0024] When applied to the foam cover, the layer does not affect
porosity of the foam. In other words, the layer is not sufficient
to block the pores of the foam or to affect the air permeability in
any way. However, the entire surface of the pores is made liquid
repellent, and this is sufficient to ensure that liquids do not
penetrate the foam.
[0025] However, similar advantages occur in relation to devices
which incorporate small microphones such as communications devices
and sound and audio systems as defined above, and in particular
mobile phones, where coating of the finished phone may further
enhance the levels of protection.
[0026] Electronic or electrical devices treated in this way are
protected to a significant degree, against water and oil
damage.
[0027] Precise conditions under which the plasma polymerization
takes place in an effective manner will vary depending upon factors
such as the nature of the polymer, the electrical or electronic
device etc. and will be determined using routine methods and/or the
techniques.
[0028] Suitable plasmas for use in the method of the invention
include non-equilibrium plasmas such as those generated by
radiofrequencies (Rf), microwaves or direct current (DC). They may
operate at atmospheric or sub-atmospheric pressures as are known in
the art. In particular however, they are generated by
radiofrequencies (Rf).
[0029] Various forms of equipment may be used to generate gaseous
plasmas. Generally these comprise containers or plasma chambers in
which plasmas may be generated. Particular examples of such
equipment are described for instance in WO2005/089961 and
WO02/28548, the content of which is incorporated herein by
reference, but many other conventional plasma generating apparatus
are available.
[0030] In general, the item to be treated is placed within a plasma
chamber together with the material to be deposited in gaseous
state, a glow discharge is ignited within the chamber and a
suitable voltage is applied, which may be pulsed.
[0031] The gas used within the plasma may comprise a vapour of the
monomeric compound alone, but it may be combined with a carrier
gas, in particular, an inert gas such as helium or argon. In
particular helium is a preferred carrier gas as this can minimises
fragmentation of the monomer.
[0032] When used as a mixture, the relative amounts of the monomer
vapour to carrier gas is suitably determined in accordance with
procedures which are conventional in the art. The amount of monomer
added will depend to some extent on the nature of the particular
monomer being used, the nature of the laboratory disposable being
treated, the size of the plasma chamber etc. Generally, in the case
of conventional chambers, monomer is delivered in an amount of from
50-250 mg/min, for example at a rate of from 100-150 mg/min.
Carrier gas such as helium is suitably administered at a constant
rate for example at a rate of from 5-90, for example from 15-30
sccm. In some instances, the ratio of monomer to carrier gas will
be in the range of from 100:1 to 1:100, for instance in the range
of from 10:1 to 1:100, and in particular about 1:1 to 1:10. The
precise ratio selected will be so as to ensure that the flow rate
required by the process is achieved.
[0033] Alternatively, the monomer may be delivered into the chamber
by way of an aerosol device such as a nebuliser or the like, as
described for example in WO2003/097245 and WO03/101621, the content
of which is incorporated herein by reference.
[0034] In some cases, a preliminary continuous power plasma, may be
struck for example for from 2-10 minutes for instance for about 4
minutes, within the chamber. This may act as a surface
pre-treatment step, ensuring that the monomer attaches itself
readily to the surface, so that as polymerisation occurs, the
coating "grows" on the surface. The pre-treatment step may be
conducted before monomer is introduced into the chamber, in the
presence of only the inert gas.
[0035] The plasma is then suitably switched to a pulsed plasma to
allow polymerisation to proceed, at least when the monomer is
present.
[0036] In all cases, a glow discharge, is suitably ignited by
applying a high frequency voltage, for example at 13.56 MHz. This
is suitably applied using electrodes, which may be internal or
external to the chamber, but in the case of the larger chambers are
internal.
[0037] Suitably the gas, vapour or gas mixture is supplied at a
rate of at least 1 standard cubic centimetre per minute (sccm) and
preferably in the range of from 1 to 100 sccm.
[0038] In the case of the monomer vapour, this is suitably supplied
at a rate of from 80-300 mg/minute, for example at about 120 mg per
minute depending upon the nature of the monomer, whilst the pulsed
voltage is applied.
[0039] Gases or vapours may be drawn or pumped into the plasma
region. In particular, where a plasma chamber is used, gases or
vapours may be drawn into the chamber as a result of a reduction in
the pressure within the chamber, caused by use of an evacuating
pump, or they may be pumped or injected into the chamber as is
common in liquid handling.
[0040] Polymerisation is suitably effected using vapours of
compounds of formula (I), which are maintained at pressures of from
0.1 to 200 mtorr, suitably at about 80-100 mtorr.
[0041] The applied fields are suitably of power of from 40 to 500
W, suitably at about 100 W peak power, applied as a pulsed field.
The pulses are applied in a sequence which yields very low average
powers, for example in a sequence in which the ratio of the time on
a time off is in the range of from 1:500 to 1:1500. Particular,
examples of such sequence are sequences where power is on for 20-50
.mu.s, for example about 30 .mu.s, and off for from 1000 .mu.s to
30000 .mu.s, in particular about 20000 .mu.s. Typical average
powers obtained in this way are 0.01 W.
[0042] The fields are suitably applied from 30 seconds to 90
minutes, preferably from 5 to 60 minutes, depending upon the nature
of the compound of formula (I) and the electrical or electronic
device etc.
[0043] Suitably a plasma chamber used is of sufficient volume to
accommodate multiple electrical or electronic devices, in
particular when these are small in size, for example up to 20,000
microphone heads can be processed at the same time with ease and
much more is capably with the correct size equipment.
[0044] A particularly suitable apparatus and method for producing
electrical or electronic devices in accordance with the invention
is described in WO2005/089961, the content of which is hereby
incorporated by reference.
[0045] In particular, when using high volume chambers of this type,
the plasma is created with a voltage as a pulsed field, at an
average power of from 0.001 to 500 w/m.sup.3, for example at from
0.001 to 100 w/m.sup.3 and suitably at from 0.005 to 0.5
w/m.sup.3.
[0046] These conditions are particularly suitable for depositing
good quality uniform coatings, in large chambers, for example in
chambers where, the plasma zone has a volume of greater than 500
cm.sup.3, for instance 0.5 m.sup.3 or more, such as from 0.5
m.sup.3-10 m.sup.3 and suitably at about 1 m.sup.3. The layers
formed in this way have good mechanical strength.
[0047] The dimensions of the chamber will be selected, so as to
accommodate the particular electrical or electronic device being
treated. For instance, generally cuboid chambers may be suitable
for a wide range of applications, but if necessary, elongate or
rectangular chambers may be constructed or indeed cylindrical, or
of any other suitable shape.
[0048] The chamber may be a sealable container, to allow for batch
processes, or it may comprise inlets and outlets for electrical or
electronic devices, to allow it to be utilised in a continuous
process. In particular in the latter case, the pressure conditions
necessary for creating a plasma discharge within the chamber are
maintained using high volume pumps, as is conventional for example
in a device with a "whistling leak". However it will also be
possible to process certain items at atmospheric pressure, or close
to, negating the need for "whistling leaks"
[0049] The monomers used are selected from monomers of formula (I)
as defined above. Suitable haloalkyl groups for R.sup.1, R.sup.2,
R.sup.3 and R.sup.5 are fluoroalkyl groups. The alkyl chains may be
straight or branched and may include cyclic moieties.
[0050] For R.sup.5, the alkyl chains suitably comprise 2 or more
carbon atoms, suitably from 2-20 carbon atoms and preferably from 6
to 12 carbon atoms.
[0051] For R.sup.1, R.sup.2 and R.sup.3, alkyl chains are generally
preferred to have from 1 to 6 carbon atoms.
[0052] Preferably R.sup.5 is a haloalkyl, and more preferably a
perhaloalkyl group, particularly a perfluoroalkyl group of formula
C.sub.mF.sub.2m+1 where m is an integer of 1 or more, suitably from
1-20, and preferably from 4-12 such as 4, 6 or 8.
[0053] Suitable alkyl groups for R.sup.1, R.sup.2 and R.sup.3 have
from 1 to 6 carbon atoms.
[0054] In one embodiment, at least one of R.sup.1, R.sup.2 and
R.sup.3 is hydrogen. In a particular embodiment R.sup.1, R.sup.2,
R.sup.3 are all hydrogen. In yet a further embodiment however
R.sup.3 is an alkyl group such as methyl or propyl.
[0055] Where X is a group --C(O)O(CH.sub.2).sub.nY--, n is an
integer which provides a suitable spacer group. In particular, n is
from 1 to 5, preferably about 2.
[0056] Suitable sulphonamide groups for Y include those of formula
--N(R.sup.7)SO.sub.2.sup.- where R.sup.7 is hydrogen or alkyl such
as C.sub.1-4alkyl, in particular methyl or ethyl.
[0057] In one embodiment, the compound of formula (I) is a compound
of formula (II)
CH.sub.2.dbd.CH--R.sup.5 (II)
[0058] where R.sup.5 is as defined above in relation to formula
(I).
[0059] In compounds of formula (II), X in formula (I) is a
bond.
[0060] However in a preferred embodiment, the compound of formula
(I) is an acrylate of formula (III)
CH.sub.2.dbd.CR.sup.7C(O)O(CH.sub.2).sub.nR.sup.5 (III)
[0061] where n and R.sup.5 as defined above in relation to formula
(I) and R.sup.7 is hydrogen, C.sub.1-10 alkyl, or
C.sub.1-10haloalkyl. In particular R.sup.7 is hydrogen or
C.sub.1-6alkyl such as methyl. A particular example of a compound
of formula (III) is a compound of formula (IV)
##STR00003##
[0062] where R.sup.7 is as defined, above, and in particular is
hydrogen and x is an integer of from 1 to 9, for instance from 4 to
9, and preferably 7. In that case, the compound of formula (IV) is
1H,1H,2H,2H-heptadecafluorodecylacylate.
[0063] In a further aspect, the invention provides a method for
protecting an electrical or electronic device against liquid damage
said method comprising exposing said device to a pulsed plasma,
comprising a compound of formula (I)
##STR00004##
[0064] where R.sup.1, R.sup.2 and R.sup.3 are independently
selected from hydrogen, alkyl, haloalkyl or aryl optionally
substituted by halo; and
[0065] R.sup.4 is a group X--R.sup.5 where R.sup.5 is an alkyl or
haloalkyl group and X is a bond; a group of formula
--C(O)O(CH.sub.2).sub.nY-- where n is an integer of from 1 to 10
and Y is a bond or a sulphonamide group; or a group
--(O).sub.PR.sup.6(O).sub.q(CH.sub.2).sub.t-- where R.sup.6 is aryl
optionally substituted by halo, p is 0 or 1, q is 0 or 1 and t is 0
or an integer of from 1 to 10, provided that where q is 1, t is
other than 0, in a gaseous state for a sufficient period of time to
allow a protective polymeric layer to form on the surface of the
electrical or electronic device.
[0066] Liquid damage from which these devices are protected include
environmental liquids such as water and in particular rain, or any
other liquid, which may be accidentally spilled onto the
device.
[0067] Suitably, the electrical or electronic device is placed in a
plasma deposition chamber, a glow discharge is ignited within said
chamber, and a voltage applied as a pulsed field.
[0068] Suitable monomers and reaction conditions for use in this
method are as described above.
[0069] The invention will now be particularly described by way of
example.
EXAMPLE 1
[0070] Microphones
[0071] A set of 100 microphones were placed into a plasma chamber
with a processing volume of .about.300 litres. The chamber was
connected to supplies of the required gases or vapours, via a mass
flow controller and/or liquid mass flow meter and a mixing injector
or any other vapour/gas introduction mechanism as appropriate.
[0072] The chamber was evacuated to between 3-10 mtorr base
pressure before allowing helium into the chamber at 20 sccm until a
pressure of 80 mtorr was reached. A continuous power plasma was
then struck for 4 minutes using RF at 13.56 MHz at 300 W.
[0073] After this period, 1H,1H,2H,2H-heptadecafluorodecylacylate
(CAS 27905-45-9) of formula
##STR00005##
[0074] was brought into the chamber at a rate of 120 milligrams per
minute and the plasma switched to a pulsed plasma at 30 micro
seconds on-time and 20 milliseconds off-time at a peak power of 100
W for 40 minutes. On completion of the 40 minutes the plasma power
was turned off along with the processing gases and vapours and the
chamber evacuated back down to base pressure. The chamber was then
vented to atmospheric pressure and the microphone heads
removed.
[0075] It was found that the microphone heads were covered with a
water and oil-repellent that protected it from challenge with
water.
* * * * *