Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
12965S9
METHOD FOR FORMING IMAGES
This invention relates to a method for forming images
from liquid coatings on substrates by exposures to actinic
radiation at different wavelengths.
Conventionally, production of an image by means of
photopolymerisation is achieved by coating a support with a
solution in a volatile organic solvent of a photopolymerisable
substance, causing or allowing the solvent to evaporate so leaving
a film of the photopolymerisable substance, irradiating the
film with actinic radiation as through an image whereby the parts
of the film struck by the irradiation become photopolymerised (and
less soluble) while those parts shielded from the irradiation
remain substantially unaffected, then dissolving away the
unirradiated, unphotopolymerised parts of the film by means of a
suitable solvent which does not dissolve the irradiated,
photopolymerised parts. This last stage is conventionally known
as "development".
It would be desirable to have a process in which a layer
of a photopolymerisable substance were applied to a support and
this layer were converted into a substantially solid, non-tacky
state, ready for irradiation through an image, without the use
of organic solvents. Not only would, in this stage, the use be
avoided of solvents which might present problems of toxicity and
flammability and also cause expense in their recovery, but
production on a continuous basis of coated supports, ready for
1 lZ96559
imagewise irradiation, would be facilitated.
We have found that this object can be achieved by the use,
in liquid form, of certain mixtures of substances which contain
either two or more materials, or at least one dual functional
material, or both, that polymerise when exposed to actinic radiation
but in which the two materials, or the two functions of the dual
functional material, are sensitive at different wavelengths.
Solidification is effected by exposure to actinic radiation at
the longer wavelength to which the mixture is sensitive, giving
a stable, solid, but still photosensitive layer. However, since
the other radiation-sensitive material or function is only sensitive
at a shorter wavelength, i.e. to actinic radiation of higher
energy, prolonged exposure to radiation of higher wavelength, i.e.
of lower energy, has a negligible effect on the solidified material.
It may therefore be solidified at the higher wavelength without
requiring very careful control over exposure times, and, following
this, may be stored for prolonged periods, in the absence of
radiation of the shorter wavelength. When desired, parts of the
composition are exposed to the radiation of a shorter wavelength
at which the composition is sensitive. Further polymerisation
then occurs in the exposed areas, so that a difference in physical
properties is caused between those areas receiving the second
exposure and those not receiving the second exposure. Contact
with a suitable solvent or other means of development removes
~Z965S9
the area receiving only one exposure and so a negative image is
formed.
United States Patent Specification No. 4 291 118 describes
a method for forming relief images from a film of a liquid
photopolymerisable material, comprising solidifying the film by
chemical hardening, usually by exposure to actinic radiation,
then re-exposing the solidified film to actinic radiation in
the form of a pattern so that parts of the film become chemically
differentiated, and then selectively removing the portions of
the film not exposed to the patterned exposure to actinic radiation
by washing with a solvent.
There is no mention made of the possibility of using
actinic radiation of two different wavelengths for the two
exposures. In the example given, both exposures are to radiation
from the same stationary pulse xenon source. The only photo-
polymerisable materials mentioned are mixtures of polyenes with
polythiols. This method is not easy to carry out successfully.
When the initial solidification is carried out by irradiation,
great care must be taken to give the right amount of irradiation
since, if too little is given, the liquid composition will not
solidify and if too much is given it will not be possible to
obtain a good image after the second irradiation. Furthermore,
the reaction between the polyene and the polythiol, which is
initiated on exposure to actinic radiation, continues when such
lZ96SS9
exposure is interrupted. For this reason the specification
recommends commencing the second irradiation less than 30 minutes,
and preferably less than 10 minutes after the first irradiation,
stating that, in many systems, a retention time between treatments
of 30 minutes or longer would result in the inability to attain
a proper differentiationin the chemical condition in the solidified
mass. This time limitation is a further constraint on industrial
utilisation of the process.
It is a feature of the process of the present invention
that the curable composition contains two different residues
through which polymerisation or curing takes place, one of these
residues being activated, directly or indirectly, with actinic
radiation at a wavelength that is longer than the longest at which
the other residue is activated, so that irradiation can selectively
solidify one residue whilst having a negligible effect on the
other, which remains photocurable. That such treatment gives a
solid coating that will form an image when irradiated a second
time, even when there is a long period between the two exposures,
is not disclosed in the prior art.
Dual radiation processes for the production of images
have also been disclosed in United States Patents Nos. 4 413 052
and 4 416 975. In the first of these a liquid composition
containing a compound having in the same molecule both a
(meth)acryloyl group and an anthryl group is solidified by
1296559
-- 5 --
exposure to actinic radiation and an image is formed by a second
exposure through a negative. The second patent describes a similar
process, except that the anthryl group is replaced by a 2,3-
disubstituted maleimido group. In neither of these patents is
there mentioned the possibility of using radiation of different
wavelengths for the two exposures. The difference between the
effects of the first and second exposures is a function of the
exposure times - the second exposure requiring 15 to 100 times
the light energy of the first. It follows that if the first
exposure is continued beyond the minimum time needed for
solidifi~ation, there is a risk that some complete cure will take
place which would prevent formation of an image. A further
drawback of the methods described in these two patents is the need
to have a prolonged second exposure, times of up to 20 minutes
being exemplified. If a more reactive system were to be used as
the second photopolymerisable material, there would be a greater risk
of the First exposure causing complete cure and hence production
of an image would be difficult or impossible. A comparatively long
second exoosure is therefore inevitable.
The use of mixtures of photocurable materials has previously
been described in US Patent Specification No. 4 426 431, which
claims such compositions as abrasion-resistant coatings. This
specification describes compositions comprising
1. a polymerisable epoxy compound, such as a polyglycidyl
--- 1296559
-- 6 --
ether of an aliphatic polyol,
2. a cationic initiator for the polymerisation of 1,
such as an aromatic onium salt,
3. a polymerisable acrylic compound, such as
pentaerythritol triacrylate,
4. a haloalkylated aromatic ketone as free radical
initiator for 3, such as a halomethylated benzophenone, and
5. a polymerisable organofunctional silane, such as an
epoxysilane or acrylated silane.
These compositions are applied as a liquid and cured by
a single exposure to U.V. radiation. The formation of images
using these compositions is not mentioned.
The use of a bifunctional curing system, both functions
of which are activated by exposure to radiant energy, is described
in US Patent Specification No. 4 428 807. This specification
describes compositions comprising a partially esterified epoxy
ester, prepared from a polyepoxide and a terminally unsaturated
monocarboxylic acid, together with a bifunctional curing system
capable of initiating both free radical and cationic polymerisation
when exposed to radiant energy. This curing system is a mixture
of a free radical initiator, such as benzoin or acyloin ethers,
with an aromatic onium salt such as p-tert.butylphenyl iodonium
hexafluorophosphate. These compositions are cured by irradiation
from a single radiant source. The compositions are used as coatings
1296559
- 7 ~
having a good adhesion to metals such as aluminium. There is
no indication that radiation in two stages from two difFerent
sources would be advantageous.
East German Patent No. 158 281, which is summarised
in Chemical Abstracts, 99 96846y discloses the formation of
images using a composition containing an ethylenically unsaturated
compound, an initiator for the radical polymerisation of this
compound, a cationically polymerisable material, and a co-
initiator for this. An exemplified composition contained glycidyl
methacrylate, an acrylic acid-ethyl acrylate-styrene copolymer,
benzoin isopropyl ether, and p-methoxy benzenediazonium hexafluoro-
phosphate. These compositions, which are stated to have improved
photosensitivity, a high crosslinking rate, and improved mechanical
properties, are cured by a single exposure to radiation.
The formation of images by a process in which solidification
is first effected at one wavelength, and then the image is formed
by a second exposure at a shorter, (i.e. more energetic) wavelength
has not hitherto been described.
This invention therefore provides a process for the
production of an image which comprises
(i) applying to a substrate a layer of a liquid
composition comprising either
I (A) a residue that is polymerisable by means of free
radicals, together with
'~ ~
1296559
-- 8 --
(B) a radiation activated, free radical-forming polymerisation
initiator for (A) and
(C) a radiation-curable residue that is different from (A),or
II (A), (B) and (C) together with
(D) a radiation-activated catalyst for the cure of (C),
the residue (C) being curable through activation thereof, or through
activation of the catalyst (D), by radiation having a wavelength that
is shorter than that at which the residue (A) is polymerizable by
activation of initiator (B),
(ii) subjecting the composition to actinic radiation having a wavelength
at which the initiator (B) is activated but at which the residue
(C) and/or the catalyst (D) are not substantially activated, thereby
polymerising (A) such that the layer of liquid composition is
solidified, but remains curable,
(iii) subjecting the solidified layer in a predetermined pattern
to actinic radiation having a wavelength that is shorter than that
of the radiation used in stage (ii) and at which the radiation-
curable residue (C) and/or the catalyst (D) is activated, such that
in the exposed areas (C) is substantially cured, and
(iv) removing areas of the solidified layer that have not been
substantially cured.
The expression "subjecting..... in a predetermined pattern to
actinic radiation" includes both exposure through an image-bearing
transparency consisting of opaque and transparent parts, and also
subjection to a beam of actinic radiation moved in a predetermined
pattern, for example as directed by a computer, so as to form an
image.
The curable liquid compositions used in accordance with
B
1296559
- 8A -
the present invention may comprise a mixture of one or more substances
that are polymerised t~y exposure to actinic radiation at a certain
\
B~
-- ~296559
_ 9 _
wavelength, together with one or more substances that are polymerised
by exposure to actinic radiation only at a shorter wavelength.
Alternatively, it may comprise one or more "dual-functional"
substances, that is substances having in the same molecule two
types of photopolymerisable function, one of which is activated only
by irradiation at a wavelength that is shorter than that at which
the other may be activated. The compositions may further comprise a
mixture of one or more dual functional substances, as described,
together with one or more substances that are polymerised by
exposure to actinic radiation at the longer or shorter wavelengths
at which the dual functional material is polymerised.
In a preferred method, the first irradiation is effected
using radiation in the visible spectrum, and the second irradiation
is effected using ultraviolet radiation; however both irradiations
may be made using ultraviolet radiation, but of different wavelengths.
Residues that are polymerisable by means of free radicals
suitable for use as part (A) of the liquid composition, are well
known and are preferably esters of ethylenically unsaturated
monocarboxylic acids, vinyl group containing compounds, or mixtures
of a polyene with a polythiol.
Preferred esters of ethylenically unsaturated monocarboxylic
acids have at least one group of formula
CH2=C(R1)Cûû-
1296SS9
- 10 -
where
R1 is a hydrogen, chlorine, or bromine atom or an alkyl
group of 1 to 4 carbon atoms, especially a hydrogen atom or a
methyl group. Suitable such esters are acrylates and 2-substituted
acrylates of monohydric alcohols such as 2-methoxyethanol,
2-cyanoethanol, furfuryl alcohol, glycidol, and cyclohexanol,
and full or partial esters of polyhydric alcohols such as butane
diol, pentaerythritol, dipentaerythritol, tri- and tetra-
ethylene glycols, trimethylolpropane and glycerol. Also suitable
are esters formed by reaction of an alkylene oxide, particularly
ethylene oxide or propylene oxide, with an acrylic acid, typically
2-hydroxyethyl and 2-hydroxypropyl acrylates and methacrylates.
There may also be used esters formed by reaction of a compound
containing one or more glycidyl groups, especially a mono-
or polyglycidyl ether of a mono- or polyhydric alcohol or phenol
or a N-glycidylhydantoin, with acrylic or methacrylic acid.
Other suitable compounds are esters formed by reaction of a
diepoxide with an adduct of a hydroxyalkyl acrylate or
2-substituted acrylate with a saturated or unsaturated dicarboxylic
acid anhydride such as succinic, maleic, or phthalic anhydride.
Typical such compounds include 1,4-bis(2-hydroxy-3-
acryloyloxypropoxy)butane, a poly(2-hydroxy-3-acryloyloxypropyl)
ether of a bisphenol or a phenol-formaldehyde novolak, 2,2-bis(4-
(2-hydroxy-3-(2-acryloyloxyethoxy)succinyloxypropoxy)phenyl)propane,
1-(2-hydroxy-3-acryloyloxypropoxy)-butane, -octane, and -decane,
- 1296559
bis(2-hydroxy-3-acryloyloxypropyl) adipate, 2-hydroxy-3-
acryloyloxypropyl propionate, 3-phenoxy-2-hydroxypropyl acrylate,
2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, trimethylol-
propane trisacrylate, pentaerythritol tetracrylate, and the
corresponding methacrylates.
There is a wide range of vinyl group-containing compounds
that may be used as part (A) of the liquid composition including
vinyl-substituted aromatic compounds such as styrene, alpha
methyl styrene, and vinyl toluene, vinyl esters such as vinyl
acetate, allyl compounds such as diallyl maleate and dimethallyl
fumarate, and vinyl heterocylics such as 2-, 3-, or 4-vinyl
pyridine and 2- or 3-vinyl pyrrolidine.
Polyenes that, mixed with polythiols, may be used as
part (A), have at least two groups of the formula
R2 _ R R2
- - C C = C - R2 Il
R2 _ m
or I ~ 2
-X - C = C - R III
where
the groups R2, which may be the same or different,
are selected from hydrogen, fluorine and chlorine atoms and
furyl, thienyl, pyridyl, phenyl, substituted phenyl, benzyl
and substituted benzyl, alkyl, substituted alkyl, alkoxy and
` lZ96559
- 12 -
substituted alkoxy of from 1 to 9 carbon atoms and cycloalkyl
and substituted cycloalkyl groups of from 3 to 8 carbon atoms,
the substituents being selected from chlorine and fluorine atoms
and acetoxy, nitro, acetamido, phenyl, benzyl, alkyl, alkoxy
and cycloalkyl groups,
m is an integer of from 1 to 9, and
X represents a group -NR2-, -0-, or -S-.
Polythiols that, mixed with these polyenes, may also be
used as part (A) have the general formula
R (SH)n IV
where
R3 is a polyvalent organic group free from reactive carbon-to-
carbon unsaturation and n is at least 2.
Preferably the organic group R3 is an aliphatic chain of
2 to 10 carbon atoms, an arylene group of 6 to 10 carbon atoms,
an alkarylene group of 7 to 16 carbon atoms, a cycloalkylene
group of 5 to 10 carbon atcms, or a cycloalkyl alkylene group
of 6 to 16 carbon atoms, any of which may be substituted and
may contain oxygen atoms or ester groups in the alkylene chains.
Specific examples of preferred polythiols include ethylene glycol
bis(thioglycolate), ethylene glycol bis(beta-mercaptopropionate),
trimethylol propane tris(thioglycolate), trimethylolpropane
- 13 - 1296559
tris(beta mercaptopropionate), pentaerythritol tetrakis (thioglycolate),
pentaerythritol tetrakis(beta-mercaptopropionate), and
thioglycolates, beta-mercaptopropionates and 3-mercapto-2-hydroxy-
propyl ethers of polyoxyalkylene glycols and triols such as polypropylene
ether glycol bis(beta-mercaptopropionate) and a 3-mercapto-2-
hydroxypropyl ether of a polyoxypropylene triol derived from glycerol.
The molar ratio of ene:thiol groups must be selected so
as to give a solid product on exposure to radiation, ratios within
the range 1:û.5-2 being preferred.
As mentioned above, photocurable polyene-polythiol
mixtures continue to cure even when the source of actinic radiation
is removed, so that the use of such mixtures in compositions that
are solidified and an image formed by two exposures to actinic
radiation of the same wavelength requires very careful control
and a minimum of delay between the two exposures. In the
present process however, the initial exposure may be allowed to
cure completely the polyene-polythiol component of the mixture,
so that long term storage can have very little effect on it.
The radlation curable residue present in the composition that is
unaffected by radiation of the wavelength used to cure the polyene
polythiol mixture is also unaffected by long term storage. When
the imagewise exposure is carried out at a wavelength that does
affect this second radiation curable residue, a developable
image is formed.
The polymerisation initiator (B) that forms free radicals
that polymerise the residue (A) when exposed to actinic radiation,
may be sensitive to visible light or to ultraviolet radiation.
- 14 _ ~296S59
Such initiators are known and include benzoin ethers, acyloin
ethers, halogenated alkyl or aryl derivatives, aromatic carbonyl
derivatives, metallocenes, mixtures of Group IVA organometallic
compounds with photoreducible dyes, mixtures of quinones with
aliphatic amines having hydrogen attached to an aliphatic alpha
carbon atom, aliphatic dicarbonyl compounds, optionally mixed
with an amine, 3-ketocoumarins, acyl phosphine oxides, metal
carbonyls, and mixtures of photoreducible dyes with reducing
agents. Preferred polymerisation initiators (B) are camphorquinone
with a tertiary amine having a hydrogen atom attached to an
aliphatic alpha carbon atom, such as bis(4-dimethylamino)benzo-
phenone and triethanolamine, biacetyl, dimanganese decacarbonyl,
benzil dimethyl ketal, isobutyl benzoin ether, 2,2,2-trichloro-4'-
tert.butylacetophenone, diethoxyacetophenone, coumarins having a
carbocyclic or heterocyclic aromatic ketone group in the 3-
position, such as 3-benzoyl-7-methoxy coumarin or 3-(4-cyanobenzoyl)-
5,7-dipropoxy coumarin, mixtures of photoreducible dyes, typically
methylene blue or rose bengal, with a stannane such as trimethyl
benzyl stannane, tributyl benzyl stannane, tributyl 4-methylbenzyl
stannane or dibutyl dibenzyl stannane, mixtures of photoreducible
dyes with an electron donor such as sodium benzenesulphinate or
benzenesulphinic acid, and a titanium metallocene such as bis(pi-
methylcyclopentadienyl)bis(sigma pentafluorophenyl)titanium (IV)
or bis(pi-methylcyclopentadienyl)bis(sigma hexyloxytetrafluorophenyl)
titanium (IV).
Compositions as described in which the initiator (B)
-` 1296559
- 15 -
is a metallocene or a mixture of a Group IVA organometallic
compound with a photoreducible dye are themselves new. This
invention therefore provides new compositions, suitable for use
in the process described comprising either
I (A) a residue that is polymerisable by means of free
radicals, together with
(B) a radiation-activated, free radical forming polymerisation
initiator for (A) that is a metallocene or a mixture of a Group IVA
organometallic compound with a photoreducible dyej and
(C) a radiation-curable residue that is different from (A),or
Il (A), (B) and (C) together with
(D) a radiation-activated catalyst for the cure of (C),
the residue (C) being curable through activation thereof, or through
activation of the catalyst (D), by radiation having a wavelength that
is shorter than that at which the residue (A) is polymerizable by
activation of initiator (s).
Preferred metallocenes that are used in the new compositions
are the titanocenes of formula
R4 \ / R5
Ti V
R4 ~ ~ R6
where
each group R4 is independently selected from an optionally
substituted cyclopentadienyl or indenyl group or together they
form an alkylidene group of 2 to 12 carbon atoms, a cycloalkyl-
idene group having from 5 to 7 carbon atoms in the ring, a group
si(R7)2 or Sn(R7)2, or an optionally substituted group of formula
.~ .
--` lZ96559
~ x1~
x1 denotes a methylene, ethylene, or 1,3-propylene group,
R denotes a 6-membered carbocyclic or 5- or 6-membered
heterocyclic aromatic ring, substituted by a fluorine atom in at
least one of the two positions ortho to the metal-carbon bond,
the ring optionally being further substituted, or
R5 with R6 denotes a group -Q-Y-Q-,
Q denotes a 5- or 6-membered carbocyclic or heterocyclic
aromatic ring, in which each of the two bonds ;s ortho to-the Q-Y
bond, and each position meta to the Q-Y bond is substituted by
fluorine, the groups Q optionally being further substituted,
Y denotes a methylene group, an alkylidene group having
from 2 to 12 cabon atoms, a cycloalkylidene group having from
5 to 7 carbon atoms in the ring, a direct bond, a group NR7, an
oxygen or sulphur atom, or a group -S02-, -CO-, -si(R7)2- or
-Sn(R7)2_,
R6 denotes an alkynyl or phenylalkynyl group that may be
substituted, an azido or cyano group, or a group of formula
si(R7)2 or Sn(R7)2, or it has the same meaning as the group R , and
1296S59
R7 denotes an alkyl group of from 1 to 12 carbon ato~s,
a cycloalkyl group of from 5 to 12 carbon atoms, an aryl group of
from 6 to 16 carbon atoms, or an aralkyl group of from 7 to 16 carbon
atoms.
'I . '~
The R groups are preferably idencical. SuiCable subst~tuenCs for R
are: linear or branched alkyl, alkoxy and alkenyl of preferably up
co 18, especially up co 12 and most preferably up co 6, carbon
acoms, e.g. methyl, eChyL, propyl, isopropyl, n-butyl, tert-butyl,
pentyl, hexyl, octyl, decyl, dodecyl, cetradecyl, he~adecyl,
octadecyl and corresponding alkenyl and alkoxy groups; cycloalkyl
and cycloalkenyl containing preferably 5 co 8 ring carbon acoms,
e.g. cyclopencyl, cyclohexyl, cyclohepcyl, meChylcyclopencyl and
mechylcyclohe~yl; aryl of preferably 6 to 16 carbon atoms and
aralkyl of preferably 7 co 16 carbon atoms, e.g. phenyl, naphthyl,
biphenyl, benzyl and phenylechyl; nitrilo, halogen, preferably F, Cl
and Br, and also amino, preferably tertiary amino which may contain
linear or branc'ned alkyl groups of 1 to 12, preferably 1 co 6,
carbon atoms, in parcicular mechyl or ethyl, or phenyl and benzyl,
which amino groups can also be quaternised, in particular wich
linear or branched alkyl halides containing preferably 1 to 12
carbon aComs, preferably methyl or echyl halides; linear or branched
aminoalkyl, preeerably tertiary aminoalkyl which may also be
quaternised, in particular with alkyl halides, and the alkylene
group in the aminoalkyl can be linear or branched and concains
preferably 1 to 12, most preferably 1 to 6, carbon acoms, and is
most preferably -branched Cl-Cl2alkyl.
The radicals R4 may contain 1 to 3 substicuents, but preferably
contain one substituent. It is preferred chat both subseituencs R
are cyclopentadienyl or meehylcyclopentadienyl .
Alkylidene groups X1 and Y preferably contain 2 to 6 carbon
atoms.~ Exemplary of alkylidene groups and cycloalkylidene
groups X1 and Y are ethylidene, 2,2-propylidene, butylidene, he~yl-
idene, phenylmechylene, diphenyl-methyl2ne, cyclopenCylidene and
cyclohexylidene. X is most preferably mechylene. R as alkyl
.
lZ96559
- 18 -
preferably contains 1 to 6 carbon atoms and is e.g. methyl, ethyl,
propyl, butyl or hexyl; R as cycloalkyl is preferably cyclopentyl
or cyclohexyl; and as aryl is preferably phenyl; and as aralkyl is
preferably benzyl.
R5 is preferably substituted in both ortho-positions by fluorine.
R as carbocyclic aromatic and fluorine-substituted ring may be
indene, indane, fluorene, naphthalene and preferably phenyl.
Examples are: 4,6-difluoroinden-5-yl, 5,7-difluoroind-6-yl,
2,4-difluorofluoren-3-yl, 1,3-difluoronaphth-2-yl and, preferably,
2,6-difluorophen-1-yl.
R as heterocyclic aromatic 5-membered ring preferably contains one
hetero-atom and, as 6-membered ring, contains preferably 1 or 2
hetero-atoms. Examples of such rin~s substituted by two fluorine
atoms are: 2,4-difluoropyrrol-3-yl, 2,4-difluorofur-3-yl, 2,4-di-
fluorothiophen-3-yl, 2,4-difluoropyrid-3-yl, 3,5-difluoropyrid-4-yl
and 4,6-difluoropyrimid-5-yl.
R and R6 together as a group of formula -Q-Y-Q- may be e.g.:
~-- -- N- o-N
R ~
~Y_ , . ~Y_o ~ ,
\ / \ / \ / \ /
,=. .=. ~=o o ~
/ \ / \ / \ / \
F F F F
-- -- -N N--
N ~Y- N , ~-Y-
\/\/ \/\/
= o = -
/\ /\ /\ /\
F F F F
-- lZ96559
- 19 -
F F
/ \ / \
~ l andll ll ll ll
~y~
\/ \/ /\/ \/\
E E F E E F
wherein E is 0, S or NH. Y is preferably methylene, ethylidene,
2,2-propylidene, a direct bond, or 0.
The radicals R5and the groups ~ in groups -Q-Y-Q- can
be partly or completely substituted by further groups. Suitable
groups are: linear or branched alkyl or alkoxy, each preferably of
l to 18, most preferably l to 6, carbon atoms, e.g. methyl, ethyl,
propyl, butyl, pentyl, hexyl, and the correspondinv alkoxy groups,
with methy], methoxy and hexyloxy being preferred;
cycloalkyl containing preferably 5 or 6 ring carbon atoms, aryl of
preferably 6 to 16 carbon atoms and aralkyl of preferably 7 to 16
carbon atoms, e.g. cyclopentyl, cyclohexyl, phenyl or benzyl;
hydroxyl, carboxyl, CN, halogen such as F, Cl or ~r, and amino,
preferably tertiary amino which may be quaternised with an alkyl
halide such as methyl chloride, methyl bromide or methyl iodide,
examples of amino groups being methylamino, ethylamino, dimethyl-
amino, diethylamino, pyrrolidyl, piperidyl, piperazyl, morpholyl,
N-methylpiperazyl;
alkoxycarbonyl containing preferably l to 18, most preferably l to
6, carbon atoms in the alkoxy moiety, aminocarbonyl containing one
or two Cl-Cl2alkyl groups in the amino group, or aminocarbonyl
containing heterocyclic amines such as pyrrolidine, piperidine,
piperazine, N-methylpiperazine, and morpholine;
aminoalkyl, especially tertiary aminoalkyl which preferably contains
Cl-C6alkyl groups and which may be quaternised with an alkyl halide,
most preferably tertiary aminoalkyl which may be substituted by
Cl-C6alkyl, e.g. dimethylaminomethyl and trimethylammoniummethyl
iodide.
559
R6 as alkynyl is e.g. 2-butynyl and, preferably, propargyl.
Examples of substituents for R as phenylalkynyl are halogen such as
F, Cl, Br, Cl-C6alkyl and Cl-C6alkoxy, carboxyl, OH and C~. R6
preferably has the meaning of R .
In a preferred embodiment of the invention, R and R in formula V
are unsubscicuted or substituted 2,6-difluorophen-1-yl or RS and R6
together form a radical of the formula
// \\ /! ~
y_ ~
\ ./ \ /
.=, ~=,
/ \ / \
F F
wherein Y has the above meaning and is in parcicular a di-ect bond,
-CH2 or-O-.
A preferred group of meCallocenes of ehe formula V comprises those
compounds wherein each R4 is ~-cyclopentadienyl or ~-cyclopentadien-
yl which is substituted by Cl-C4alkyl, preferably meChyl, and each
of R and R is a radical of che formula
- o
R `\\ Q2 Va
;.!
/ \ 3
wherein each of Q , Q and Q independently is a hydrogen atom, F,
Cl, Br, a tertiary amino group, preferably morpholino group~or an
alkoxy group, preferably a methoxy or hexyloxy group . The
amino or alkoxy group is preferably attached in the para-position to
the free bond. A preferred subgroup comprises those metallocenes
of the formula V, wherein each R4 is ~-methylcyclpentadienyl or
~r-cyclopentadienyl, and each of R5 and R6 is a radical of the
~296SS9 ~
,. ..
- 21 _
formula Va, wherein ql and ~ are H, F, Cl or 8r and Q2 is H,
f or alkoxy. Preferably, each of q1 and ~3 independently is a
hydrogen or fluorine atom, and Q2 i~ fluorine, or hexyloxy.
Compounds of formula V, and their preparation,sre described `-
in Australian Patent Specification No. ~424454, published on August 16,1984
Preferred Group IVA organometallic compounds used in the
new compo~itiona are organoJtJnnanes of formula VI
9 ~ R8
~ ~Rz-Sn - R VI ~ ;
where r. ".
R8 denote~ an alkyl group of from 1 to 4 carbon atoms, or
an alkenyl or olkynyl group of from 2 to 4 carbon atoms, and
R9 denotea a hydrogen or halogen atom or an alkyl or ;~
alkoxy group of from 1 to 4 carbon atom~.
Prererred compounds of formulo VI nr~ those where R denotes
an alkyl group ot 1 to 4 carbon atom~ and R9 denotes ~ hrdrogen
atom or an aLkyl group o- 1 to 4 carbon atoms. ~s
The~e organostannane~ are prepared by Grignard coupling ~-
of a benzyl magne~ium halide with a trialkyltin halide in an inert
~olvent, ~ollo~ed by filtrstion, aqueou~ wa~hing and distillation i;:
of the product.
Pre~erred photoreducible dyes that are used with these
organo~tannanea are methylene blue and rose bengal.
The radiation curable residue (C) m~y be one in which
polymerisation ia effected by direct activation of photosensitive ;Sr
`? !,"
A }~
-- 1296559
- 22 -
groups through radiation, or those in which the radiation activates
a suitable catalyst (D) which then activates polymerisable groups.
Materials having photosensitive groups are well known and
include those having at least two, and preferably three or more,
groups which are azido, coumarin, stilbene, maleimido, pyridinone,
chalcone, propenone, pentadienone, anthracene, or acrylic ester
groups which are substituted in their 3- position by a group having
ethylenic unsaturation or aromaticity in conjugation with the
ethylenic double bond of the acrylic group.
Materials in which photopolymerisation is effected by
activation of a photoinitiator which then activates polymerisable
groups include epoxide resins, phenolic resins, cyclic ethers, vinyl ethers,
cyclic esters, cyclic sulphides, cyclic amines and organosilicon
cyclics in combination with , as D, a radiation-sensitive aromatic 'onium
salt, such as diazonium, sulphonium, iodonium, and sulphoxonium
salts, or a radiation-sensitive aromatic iodosyl salt.
Examples of suitable azides are those containing at least
two groups of formula
N3Ar- VII
where Ar denotes a mononuclear or dinuclear divalent aromatic
radical containing in all from 6 to at most 14 carbon atoms,
especially a phenylene or naphthylene group.
~Z~6559
Examples of suitable coumarins are those containing groups
of the formula
~ R1û _ VIII
where R10 is an oxygen atom, a carbonyloxy group (-COO-), a
sulphonyl group, or a sulphonyloxy group.
Examples of those containing stilbene groups are those
containing groups of the formula
R11 ~ -CH=CH- IX
.
where R11 is the residue, containing up to 8 carbon atoms in
all, of a five or six-membered nitrogen-containing heterocyclic
ring, fused to a benzene or naphthalene nucleus, and linked through
a carbon atom of the said heterocyclic ring adjacent to a nitrogen
hetero atom thereof to the indicated benzene nucleus, such as a
benzimidazolyl, benzoxazolyl, benzotriazolyl, benzothiazolyl, or a
naphthotriazolyl residue.
Examples of those containing maleimide units are those
having groups of the formula
R1 Cû ~
ll N- X
C
S59
- 24 -
where each R12 is an alkyl group of 1 to 4 carbon atoms, a chlorine
atom, or a phenyl group, and especially a methyl group.
Examples of those containing pyridinone units are those
- having groups of the formula
R a ~ XI
where
R13 is an aliphatic or cycloaliphatic radical of 1 to 8
carbon atoms and
a is zero or an integer of 1 to 4.
Examples of compounds containing chalcone, propenone, and
pentadienone groups are those containing groups of formula
R14a R14a R14a
R9 ~ ~ R14
XII XIII
where
each R14 is a halogen atom, or an alkyl, cycloalkyl,
alkenyl, cycloalkenyl, alkoxy, cycloalkoxy, alkenoxy, cycloalkenoxy,
1296559
- 25 -
carbalkoxy, carbocycloalkoxy, carbalkenoxy, or carbocycloalkenoxy
group, such organic groups containing 1 to 9 carbon atoms, or is a
nitro group, or a carboxyl, sulphonic, or phosphoric acid group
in the form of a salt,
a has the meaning previously assigned,
R15 represents a valency bond or a hydrogen atom,
y1 represents a grouping of Formula o
, 1 e ~ C-C=CH ~ H=C-C_
tcH=c ~ c t c =CH ~ R18
XIV XV
or
-CH=C-C ~ O R19
C- C=CH- XVI
R16 and R17 are each individually a hydrogen atom, an alkyl
group, e.g., of 1 to 4 carbon atoms, or an aryl group, preferably
a mononuclear group such as a phenyl group, or R16 and R17
conjointly denote a polymethylene chain of 2 to 4 methylene groups,
R18 and R19 are each a hydrogen atom, an alkyl group, e.g.,
of 1 to 4 carbon atoms, or an aryl group which is preferably a
mononuclear group such as a phenyl group,
b and c are each zero, 1, or 2, with the proviso that
-~ -- lZ96559
- 26 -
they are not both zero, and
Z is an oxygen or sulphur atom.
Suitable anthracenes are those containing anthryl groups,
such as 1-, 2-, or 9-anthryl groups, which are unsubstituted or
have one or two bromo, chloro, methyl, or nitro substituents.
Suitable 3-substituted acrylates contain groups of the
general formula
R2ocH=c(R21)coo- XVII
where
R20 is an aliphatic or mononuclear aromatic, araliphatic,
or heterocyclic group which, as already indicated, has ethylenic
unsaturation or aromaticity in conjugation with the ethylenic
double bond shown, such as phenyl, 2-furyl, 2- or 3- pyridyl,
prop-2-enyl, or styryl group, and
R21 is a hydrogen or chlorine atom or a methyl or ethyl
group.
Typical epoxide resins that may be used as component (C)
are polyglycidyl esters obtainable by reaction of a compound
containing two or more carboxylic acid groups per molecule with
epichlorohydrin or glycerol dichlorohydrin in the presence of an
alkali. Such glycidyl esters are preferably derived from aliphatic
di and polycarboxylic acids, e.g., succinic acid, glutaric acid,
-` lZ9655g
- 27 -
adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic
acid, or dimerised or trimerised linoleic acid; from cycloaliphatic
di and polycarboxylic acids such as 1,2-cyclohexane dicarboxylic
acid, and from aromatic di and polycarboxylic acids such as phthalic
acid, isophthalic acid, and terephthalic acid.
Further examples are di and polyglycidyl ethers obtainable
by reaction of a compound containing two or more free alcoholic
hydroxyl and/or phenolic hydroxyl groups per molecule with
epichlorohydrin under alkaline conditions or, alternatively, in
the presence of an acidic catalyst and subsequent treatment with
alkali. These ethers may be made from acyclic alcohols such as
ethylene glycol, poly(oxyethylene)glycols, propane-1,2-diol,
poly(oxypropylene) glycols, propane-1,3-diol, butane-1,4-diol,
poly(oxytetramethylene) glycols, glycerol, pentaerythritol,
and poly(epichlorohydrin). Or they may be made from mono and
polynuclear phenols, such as resorcinol, bis(4-hydroxyphenyl)
methane, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl) sulphone,
1,1,2,2-tetrakis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)-
propane (otherwise known as bisphenol A), 2,2-bis(3,5-dibromo-4-
hydroxyphenyl)propane, and novolaks formed from aldehydes such as
formaldehyde with a phenol.
Other suitable compoents (C) are poly(N-glycidyl) compounds
including, for example, those obtained by dehydrochlorination of
-- h~ r~
- 28 -
the reaction products of epichlorohydrin with amines containing
at least two amino-hydrogen atoms, such as aniline, n-butylamine,
and bis(4-aminophenyl)methane; triglycidyl isocyanurate; and
N,N'-diglycidyl derivatives of cyclic alkylene ureas, such as
ethyleneurea, and of hydantoins such as 5,5-dimethylhydantoin.
Epoxide resins in which some or all of the epoxide groups
are not terminal may also be employed, such as vinylcyclohexene
dioxide, limonene dioxide, dicyclopentadiene dioxide, 4-oxatetra-
cyclo[6.2.1.02'7.03'5]undec-9-yl glycidyl ether, the bis(4-
oxatetracyclo[6.2.1.02'7.03'5]undec-9-yl) ether of ethylene glycol,
3,4-epoxycyclohexylmethyl 3',4'-epoxycyclohexanecarboxylate and
its 6,6'-dimethyl derivative, the bis(3,4-epoxycyclohexanecarboxylate)
of ethylene glycol, 3-(3,4-epoxycyclohexyl)-8,9-epoxy-2,4-dioxaspiro-
[5,5]undecane, and epoxidised butadienes or copolymers of butadiene
with ethylenic compounds such as styrene and vinyl acetate. If
desired a mixture of compounds (C) may be used.
Especially preferred epoxide resins used as component (C)
in the process of this invention are diglycidyl ethers of dihydric
phenols such as 2,2-bis(4-hydroxyphenyl)propane and bis(4-hydroxy-
phenyl)methane and of dihydric alcohols such as of butane-1,4-diol,
polyglycidyl ethers of novolaks, especially cresol-formaldehyde
novolaks and cycloaliphatic epoxide resins such as 3,4-epoxycyclohexyl-
methyl-3',4'-epoxycyclohexanecarboxylate and 1,4-bis(3,4-epoxy-
cyclohexylmethyl)butanedicarboxylate.
~96S5~
- 29 -
Onium salts which, when combined with an epoxide resin
or other cationically-polymerisable substances, give
photopolymerisable mixtures, are described in United States
Patent Specifications Nos. 4 05B 400 and 4 058 401. Suitable
sulphoxonium salts that may be used for the same purpose are
disclosed in United States Patent Specifications Nos. 4 299 938
4 339 567 and 4 383 025. Iodonium salts that may also be used
for this purpose are described in British Patent Specification No.
1 516 352. Iodosyl salts that may be used are described in
European Patent Specification No. û 104 143.
If desired the free radical polymerisable residue (A)
and the radiation curable residue (C) may form part of the same
molecule, i.e. a dual-functional material. Preferred dual
functional materials are those containing an ester of an
ethylenically unsaturated monocarboxylic acid, particularly
an ester group of formula I, with an epoxide group, a compound
containing both an ethylenically unsaturated carboxylic ester
group and an anthryl group or a substance containing
both an epoxide group and an ally1 or methallyl group.
The first type of dual functional material may be
prepared by reaction of an unsaturated monocarboxylic acid with a
stoichiometric deficit of a di- or polyepoxide. The second type
of dual functional material may be prepared by reaction of a
compound containing both a 1,2-epoxide group and an unsaturated
ester group with an anthryl compound containing a group capable
~296559
- 30 -
of reaction with the 1,2-epoxide group, such as a carboxylic acid,
phenolic, or alcoholic hydroxyl or imido group. The third type of
dual functional material may be an allylic epoxide resin produced,
for example,by glycidylation of an allyl-substituted bisphenol.
The reaction of epoxide with unsaturated acids follows well known
procedures. Reaction of an epoxide with a suitable anthryl compound
is described in US 4 413 052.
The weight ratio of free radical polymerisable material
(A) to radiation curable residue (C) is not critical, as long as
effective amounts of both components are used. Where (A) and (C)
are on separate molecules, the weight ratio (A):(C) is generally
within the range 1:0.1-10, especially 1:1-5. The amount of
polymerisation initiator (B) that is used is also not critcal, as
long as there is enough to initiate polymerisation of (A) during
the first exposure to actinic radiation. Typical amounts of (B)
are within the range 0.1-50 parts by weight of (B) per 1ûO parts
of (A), especially 0.2 to 10 parts.
Suitable sources of actinic radiation include carbon arcs,
mercury vapour arcs, fluorescent lamps with phosphors emitting
ultraviolet light, argon and xenon glow lamps, tungsten lamps,
and photographic flood lamps. It is important that the first
irradiation is effected using radiation of a longer wavelength
than that used in the second irradiation. The use of filters,
to screen out irradiation of short wavelengths, may be found to
be advantageous since, in this way, a single, wide spectrum
- 1296~S~
- 31 -
source of irradiation may be used. If such a single source of
radiation is used, the first exposure is effected with a
filter preventing short wavelength irradiation from reaching
the composition, so that only residue (A) is polymerised. In
the second exposure, the whole unfiltered spectrum of radiation
may be used, so that the short wavelength irradiation effects
cure of residue (C).
The compositions as described may be applied as a
liquid to a substrate such as steel, aluminium, copper, paper,
silicon or plastics. After the coating has been applied, the
first exposure takes place, resulting in solidification of the
composition. The coated substrate is then stable and may be
stored for prolonged periods away from short wavelength actinic
irradiation. When desired, the coated substrate is given an
imagewise exposure to actinic radiation of a shorter wavelength
than that used in the first exposure. Those parts of the coating
that have not received the second exposure may then be removed,
usually by washing in a suitable solvent such as cyclohexanone,
2-ethoxyethanol, diethylene glycol monobutyl ether, gamma butyrolactone,
toluene, acetone, propylene carbonate, 1,1,1-trichloroethane and
mixtures thereof, and aqueous solvents such as dilute aqueous sodium
carbonate or sodium hydroxide. The coated substrate may be heated
after the imagewise exposure and before development to increase
resistance to developer in exposed areas of the coating. Dry development,
such as plasma etching, may also be used. Thus the process of this
5S9
invention may be used in the production of printing plates and
printed circuits, using well known techniques.
The following examples illustrate the lnvention. All
parts are by weight. The resins used in these examples are as
follows:
Resin 1
This denotes an epoxidised o-cresol novolak having a
softening point of 99C and an epoxide content of 4.2
equivalents/kg.
Resin 2
_
This denotes 2-hydroxyethyl methacrylate.
Resln 3
This denotes 1,4-bis(3,4-epoxycyclohexylmethyl)butane
dicarboxylate, having an epoxide content of 4.8 equivalents/kg.
Resin 4
This denotes trimethylolpropane trismethacrylate.
Resin 5
.
Thls is prepared by the following method:
bisphenol A diglycidyl ether (250 9) is heated to 120C and a
mixture of acrylic acid (94.9 9), chromium III tris octanoate
(0.16 9; 5O solution in ligroin), and 2,6-di-tert.butyl-4-methyl
phenol (0.5 9) is added dropwise with stirring. Heating is
continued for 5 hours, by which time the epoxide content of the
mixture is negligible. The product, Resin 5, is 2,2-bis(4-(3-
acryloyloxy-2-hydroxypropoxy)phenyl)propane.
`` - lZ96559
- ~3 -
Resin 6
This is prepared by the following method:
anthracene-9-carboxylic acid (4 9) is added to a mixture at
100C of glycidyl methacrylate (2.8 9), tetramethylammonium
chloride (0.1 9), and 2,6-di-tert.butyl-4-methylphenol (0.1 9).
The mixture is stirred at 100C for 4 hours, by which time the
epoxide content is negligible, to give Resin 6, which is 2-
hydroxy-3-methacryloyloxypropyl anthracene-9-carboxylate.
Resin 7
This denotes 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane
carboxylate.
Resin 8
This is prepared according to the procedure described in
J. Polym. Sci. Polym. Chem. (1983) 21 1785.
A mixture of bisphenol A (45.6 9, 0.2 mole), powdered sodium
hydroxide (24 9,0.6 mole) and dimethyl sulphoxide (DMS0) (75 ml)
is heated at 70C for an hour under a nitrogen blanket. 2-Chloro-
ethylvinyl ether (64 9, 0.6 mole) is added dropwise over 30 minutes,
keeping the temperature below 80C. When the addition is complete,
a further 25 ml DMS0 is added and the reaction mixture is stirred
for a further 5 hours at 70C. This is cooled and poured into water
(100 ml). An oily layer separates which is dissolved in diethyl ether
(60 ml). The ethereal layer is washed with water (3 x 50 ml), dried
(anhydrous magnesium sulphate), and concentrated to dryness on a
12965S9
- 34 -
rotary evaporator. The pale yellow oil is recrystallised from 95O
ethanol to give 59.8 9 of Resin 8, 2,2-bis(4-vinyloxyethoxyphenyl)-
propane, IR (KBr disc) 3070, 3050, 2980, 2950, 2939, 2880, 1620,
1511, 1453, 1322, 1251, 1209, 1075, 982, 841, 821 cm 1; NMR
(Acetone-d6) 1.65 (s, 6H), 3.8-4.5 (m, 12H), 6.5-7.5 (m, 10H~.
Resin 9
This denotes trimethyiolpropane trisacrylate.
Resin 10
This denotes the tris(3-mercapto-2-hydroxypropyl) ether
of a polyoxypropylene triol derived from glycerol and having
an average molecular weight of 800.
Resin 11
This denotes a diglycidyl ether of 2,2-bis(3-allyl-4-
hydroxyphenyl)propane, having an epoxide content of 4.5 equivalents/kg.
Dimethyltricyclo~3.3.1.1.3'7)decane-1-carbonylmethyl-sulfoxonium
hexafluorophosphate used in Examples11 and 14 is prepared as
described in EP-A-0 164 314.
`` ~2~ 9
- 35 -
EXAMPLE 1
A mixture of Resin 1 (27.5 parts), Resin 2 (11 parts),
and Resin 3 (10 parts) is added to a mixture of Rose bengal
(0.05 part), tri n-butyl benzyl stannane (5 parts), and
triphenylsulphonium hexafluorophosphate (5 parts), and stirred
until homogeneity is obtained.
The mixture is coated onto a copper clad laminate to a
thickness of 15 micrometres. The coated laminate is then irradiated
using a 500w tungsten-halogen lamp producing radiation with a
wavelength over 400 nm at a distance of 200 mm for 3 minutes, by
which time the coating is solid and non-tacky. The solidified
coating is then irradiated through a transparency using a 5000w
metal halide lamp producing radiation within a wavelength of
340-450 nm, at a distance of 750 mm for 3 minutes. Development
in gamma butyrolactone produces a negative image of the
transparency.
EXAMPLE 2
A mixture of Resin 1 (27.5 parts), Resin 2 (11 parts),
Resin 3 (10 parts) and Resin 4 (1.4 parts) is added to a mixture
of methylene blue (0.05 part), tri n-butyl benzyl stannane
(5 parts) and triphenylsulponium hexafluorophosphate (5 parts),
and mixed to obtain a homogeneous solution. The mixture is
coated onto a copper clad laminate to a thickness of 15 micrometres
-`` 12~?6SS~
- 36 -
and the coating is solidified by irradiation using a 500w tungsten
halogen lamp at a distance of 200 mm for 32 minutes. The solidified
coating is then irradiated through a transparency using a 5000w
metal halide lamp at a distance of 750 mm for 3 minutes. Development
in gamma butyrolactone gives a negative image of the transparency.
EXAMPLE 3
Resin 1 (6.5 parts), Resin 2 (3.5 parts), Resin 3 (1 part)
and Resin 5 (1 part) are mixed, and the mixture combined with
Rose bengal (0.02 part), di n-butyl diphenyl stannane (0.3 part)
and triphenylsulphonium hexaflurophosphate (0.3 part). The mixture
is coated onto a copper clad laminate to a thickness of 6-a
micrometres, and solidified by exposure to a 400w metal halide
lamp, with an output at 420 nm, at a distance of 400 mm for
4 mins. The solidified coating is then irradiated through a
transparency using a 125w metal halide lamp with an output at 313 nm,
at a distance of 750 mm for 3 minutes. Development in gamma
butyrolactone gives a negative image of the transparency.
EXAMPLE 4
Resin 1 (65 parts) and Resin 2 (35 parts) are mixed
with triphenyl sulphonium hexafluorophosphate (5 parts) and
bis(pi~methylcyclopentadienyl) bis(sigma pentafluorophenyl)-
titanium (IV) (1 part) in acetone (1 part). The mixture is coated
onto a copper clad laminate to a thickness of 30 micrometres, and
irradiated for 1 minute under nitrogen, using the 500w tungsten
1 29~i Sr~;9
- 37 -
halogen lamp described in Example 1, at a distance of 200 mm.
The solidified, non-tacky coating is then irradiated
through a transparency using the 500ûw metal halide lamp described
in Example 1. Irradiation is at a distance of 750 mm and
continues for 4 minutes. Development in a 3:1 mixture of gamma
butyrolactone and butyl digol (the monobutyl ether of diethylene
glycol), produces a sharp, glossy negative image of the transparency.
The laminate can be etched using an aqueous solution of ferric
chloride (40O FeCl3) at 30C for 3l minutes, leaving the coated
image intact.
EXAMPLE 5
Example 4 is repeated, replacing the triphenylsulphonium
hexafluorophosphate by an equal weight of diphenyiiodonium
hexafluorophosphate. Imagewise exposure is continued for 5
minutes, producing a clear, negative image of the transparency.
EXAMPLE 6
Resin 6 (85 parts), Resin 2 (15 parts) and bis(pi-
methylcyclopentadienyl)-bis(sigma pentafluorophenyl) titanium
(IV) (1 part) are mixed and coated onto a copper clad laminate
to a thickness of 15 micrometres. The coating is irradiated under
nitrogen using the 500w tungsten halogen lamp described in Example
1 at a distance of 200 mm for 5 minutes. The coating becomes
solid and tack-free.
~`~ 12~6S~ig
The solidified coating is then irradiated through a
transparency using a 8ûw per cm medium pressure mercury lamp
that produces radiation with a wavelength in the region of
2ûû-40û nm at a distance of 250 mm for 1 2 minutes. Development
in toluene produces a negative image of the transparency.
EXAMPLE 7
Example 4 is repeated, but to show that over-exposure
in the first irradiation is not deleterious, this first exposure
is carried out for 1 minute, to give a solid, non-tacky coating,
and the irradiation is continued for a further 5 minutes. The
second irradiation is then carried out as described in Example
4. Development in a 3:1 mixture of gamma butyrolactone and
butyl digol gives an image that is of the same quality as that
obtained in Example 4.
EXAMPLE 8
The mixture used in Example 4 is coated onto a copper-clad
laminate to a thickness of 30 micrometres and irradiated for 1 minute
under nitrogen, using the 50ûw tungsten halogen lamp described in
Example 1 at a distance of 25û mm to give a solid coating. The
coated laminate is left in laboratory daylight, from which the ultra-
violet portion is filtered out, for 1 week. The coating is then
irradiated through a negative using a 50ûOw metal halide lamp at
a distance of 750 mm for 4 mins. Development in a 3:1 mixture of gamma
butyrolactone and butyl digol produces a sharp negative image.
-- lZ96559
- 39 -
EXAMPLE 9
The mixture used in Example 5 is coated onto a copper clad
laminate to a thickness of 30 micrometres. The coating is solidified
by irradiation under nitrogen for 1 minute using the 500w tungesten
halogen lamp described in Example 1 at a distance of 200 mm. The
solidified coating is left for storage in U.V. filtered laboratory
light for 1 week. The coating is then irradiated through a negative
using a 5000w metal halide lamp at a distance of 750 mm for 5
minutes. Development in a 3:1 mixture of gamma-butyrolactone and
butyl digol produces a negative image.
EXAMPLE 10
A mixture of Resin 1 and Resin 2 in the ratio of 65:35
(100 parts) is added to rose bengal (0.5 part), tri-n-butyl
4-methylbenzyl stannane (5 parts) and triphenylsulphonium
hexafluorophosphate (5 parts). The resulting composition is
coated onto a copper-clad laminate to a thickness of 30 micrometres
and solidified by irradiation using the 500w tungsten halogen
lamp described ln Example 1 at a distznce of 25o mm for 3 minutes.
The solidified coating is left exposed to ambient light, from whicih
the ultra-violet light is filtered out, for 1 week. The coating is
then exposed through a negative using a 5000w metal halide lamp at
a distance of 750 mm for 4 minutes. On development in a 3:1 mixture
of gamma-butyrolactone and butyl digol a negative image is obtained.
lZ965S9
- 40 -
EXAMPLE 11
Resin 1 (65 parts) and Resin 2 (35 parts) are mixed with
dimethyltricyclo[3,3,1,13'7]decane-1-carbonylmethylsulphoxonium
hexafluorophosphate (5 parts), benzil dimethyl ketal (3 parts3 and
acetone (1 part). The mixture is coated onto a copper clad laminate
to a thickness of 30 micrometres. The coating is solidified by
irradiation for 30 seconds at a distance of 75O mm using a 500w
metal halide lamp fitted with a plastic filter so that light of less
than 300nm is prevented from reaching the coating. The solidified
coating is irradiated through a negative using the medium pressure
mercury arc lamp described in Example 6 at a distance of 200 mm
for two minutes. Development in a 3:1 mixture of gamma-butyrolactone
and butyl digol produces a clear negative image.
EXAMPLE 12
Resin 1 (66 parts), Resin 2 (34 parts), Resin 7 (10 parts),
triphenylsulphonium hexafluoroantimonate (10 parts), dimanganese
decacarbonyl (5 parts) and 1,1,1-trichloroethane (2 parts) are
mixed until homogeneous. The mixture is coated onto a copper-clad
laminate to a thickness of 36 micrometres. The coating is
solidified by irradiation under nitrogen using the 500w tungsten
halogen lamp described in Example 1 fitted with a filter to cut out
radiation below 450 nm at a distance of 200 mm for 15 minutes. The
solidified coating is then irradiated through a transparency using a
5000w metal halide lamp at a distance of 750 mm for 5 minutes.
Development in 1,1,1-trichloroethane with rubbing gives a negative
~ lZ96559
- 41 -
image of the transparency.
EXAMPLE 13
Resin 8 (3 parts), Resin 9 (2 parts), bis(pi-methylcyclo-
pentadienyl)bis(sigma 4-hexyloxy tetrafluorophenyl)titanium (IV)
(0.05 part) and triphenylsulphonium hexafluoroantimonate (1 part)
are mixed until homogeneous. The mixture is coated onto a copper
clad laminate to a thickness of 36 micrometres. The coat;ng is
solidified by irradiation under nitrogen using the 500w tungsten
lamp as described in Example 1 at a distance of 200 mm for 30 seconds.
The solidified coating is irradiated through a transparency using
a 5COOw metal halide lamp at a distance of 750 mm for 2 minutes.
The coating is then heated at 90C for 5 minutes and developed
in a mixture of propylene carbonate (5 parts), butyl digol (3 parts)
and gamma-butyrolactone (2 parts) to produce a negative image of
the transparency.
EXAMPLE 14
A mixture of Resin 1 (21.5 parts), Resin 11 (50 parts), Resin
10 (25 parts), ethylene glycol bisthioglycolate (10 parts), benzil
dimethyl ketal (2.5 parts) and dimethyltricyclo[3,3,1,13-7]decane-1-
carbonylmethylsulphoxonium hexafluorophosphate (3.5 parts) is coated
onto a copper clad laminate to a thickness of 30 micrometres. The
coating is solidified by irradiating through a filter preventing
light of less than 310 nm reaching the coating using a 5000w metal
halide lamp at a distance of 750 mm for 4 minutes. The solidified
lZ965.~i9
- 42 -
layer is exposed imagewise using the medium pressure mercury arc
lamp described in Example 6 at a distance of 20û mm for 3 minutes.
Development in a 3:1 mixture of gamma-butyrolactone and butyl digol
produces a negative image.
