Note: Descriptions are shown in the official language in which they were submitted.
7~7
A LIGHrr'~SENSITIVE MIXl'URE, LIt~HT-SEN,SIl'I~TE COl?YING
MATERIATJ PREPARED THEREFROM, AND A PROCES~S FOR THE
PREP~RA'rION OF A PRI~TI~ FORM FROM THE
COPYI~G l`lA:~E~IAL
~ACRGROUND OF THE INVEMTION
The invention relates to a light-sensitive
mixture containing a water-insoluble bin~er, which is
solu~le in a~ueous-alkaline solutions, an~ a liqht-
sensitive comPound, to a liq'nt-sensitive coPving
material co~ose~ of a laYer support an~ a lig~t-
., ' ~
?
~5~78~
sensiti~e laver consti~ute~ bv the mixture, and to a
orocess ~r the ~re~aration o a ~rintin~ Eorm ',~v
exPOSinq, ~evelonin~, an~ heatinq the co~Yinq
material.
Processes ~or ~he ~re~aration o~ nrin-ting
forms hv heatin~ or baking of the image laver o-E
exPosed an~ developed copYinq materials have heen
disclosed, for example, bv Britis'n Patent
Specifications ~o. 1,1~ and No. 1,1~4,744. In
these processes, a light-sensitive copvin~ material
which is either positive-~orkinq (anA ~re~era~lY con-
tains an o-quinone-~iazi(1e), or is ne~ative-workinq
(and pre~erably contains a ~-quinone-diazide), is
ex~osed in an imagewise fashion, developed, and then
~neated to a temPeratUre above 1~0C for such a ~eriod
and to such a temperature level t~at the imaqe
backqroun~, previouslY develoPed cleanlY, is stainetl
~y thermal Aecom~ositioll ~roducts o~ t~ image laver.
~uhsequentlY, the ima~e background is cleane~ again by
once more treatin~ it with develo~er solution.
~ormall~, tem~eratures o~ ~20 - ~4noc are used for
heatinq, and the duratlon o~ heatinq is a~out ; - 60
minutes. This post-treatment achieves a hardeninq of
the printin~ laver and, hence, a consi~erable exten-
sion o~ the print run. When the baking tem~eraturesare at the u~per limit of the indicated range, the
required hakint~ times are, o~ course, relativelY
short. It has heen ound that the use o~ relatively
hiqh temperatures in this Drocess is disatl~7anta~eous.
30 on t~e one hand, these temperatures cause the
~2~ 787
formatiQll of a relatively firmlv adherinq preciPitate
in the background areas, and this can ~e cleanlv
removed only ~v means of quite stronq solu~ions, and
there is also a risk o~ an attack on the printing
stencil. Moreover r at the relatively hiqh bakinq
tem~eratures or with khe relativelY long ~aking times,
there is a risk o the conventionallY used supPorts o~
aluminum beinq deforme~ an~, thus, of the printing
form obtained being damaged or rendere~ useless.
As described in German Offenlequngsschrift
~,h2~,473l the irst-~entione~ ~isadvantaqe can be
avoi~ed bv coatin~ the hackqround sur'ace he~ore
bakinq with a laver of a water-solu~le orqanic
substance or an inorganic salt, which layer can ~e
readily washed oE~ ater bakinq. To prevent a
~1e'ormation of the sup~ort, it would be desira~le,
however, to he able to 'oake at lower temperatures.
~urthermore, it would also be desira~le to be able to
avoid the additional ~rocess ste~ o' che in~ermediate
treatment with an aqueous solution.
German O~fenlegungsschrift ~o. 3,107,109
discloses a light-sensitive mixture ~or the prepara-
tion of lit-nographic printin~ plates, wherein a halo-
genated novolak is contained as hinder. The material
has an im~roved resistance to a~ueous-alkaline
develo~er solutions, to hv~rocarhon solvents~ and to
alcohol-containin~ ountain solutions. ~e ~ehavior
~uring baking o~ the develo~e~ Printinq stencils
prePare~l in accordance with this pu~lication is not
chanqe~ hY the a~dition o~ these novolaks.
_ 4 ~ ~2~7~7
In German OF~enlequnqsschri~t l~o. ~,3~2,2~0,
liqht-sensitive litho~raphic Printing ~lates are
described which contain polvvin~l ~henols as ~inders,
instead o~ novolaks~ The prin-tinq Eor~s prepared
therewith are said to be ~istinquishe~ 'oy oarticularlv
high print runs. Nothinq is stated concerning the
behavior o~ t~ese printing forms after ba'~in~.
SUM~A~Y ~F ~rHE IN~ NlrIoN
It is therefore an ob~ect Oe the present
invention to ~rovide an im~roved light-sensitive mix-
ture and a copying material ~reoared there~rom. It is
also an obiect o~ -the invention to provide such a
co~ying material which is sllitable ~or the oroduction
o~ lithoqraphic printin~ forms an~ which, a~ter expo-
sure and fleve~o~ment, can he bake~ under conditionssuch that no difficult-to-remove bakin~ remainders are
le~t on the non-i~age areas oE t~e layer support.
Anot'ner ob;ect of the invention resides in Providinq a
copYing material with whic'n an intermeaiate treatment
ste~ compeising the apPlication oE a water-soluhle
protective laver can he omitted. Still another obiect
of the invention is to provi~e a process ~or preparing
a printinq ~orm.
In accomplishinq the foreqoinq ohjects,
there has been provide~, in accordance with one aspect
o~ the ~resent invention/ a liqht-sensiti~e ~ixture
which comPrises ~1) a li~ht-sensitive composition
comPrisinq at least one liqht-sensitive compoun~ or a
li~ht-sensitive ~ombination o~ com~ounds and (2)
~inder material comorising a halogenated polvvinyl
~2~
phenol comPoun~ which is insoluhle in water ~ut
solu~le in aqueous-alkaline solutions, the solubilitY
oF sai~ mixture in an aqueous-alkaline solution l~eing
caPable of cban~inq upon exPoSure to actinic
radiation.
In Eurther accom~lishinq the ~oreqoing
o~jects, there has also heen ~rovit~e~ a liqht-sensitive
conYinq material comprise~ of a laver sup2ort an~ a
li~ht-sensitive layer which is constitu,.e-~ ~y the
above-define-1 mixture.
In accor~ance with t~e invention, there is
further ~rovi~e~ a process ~nr the ~renaration o~ a
printing form com~rising t'ne stePS o~ (a) ~re~aring a
liq'~t-sensitive copvinq material comPrisin~ a la~er
suP~ort an~ a light-sensitive laver, the soluhilitv o~
which in an aaueous-alkaline solution is caPable of
changinq u~on irra-~iation, said liqht-sensitive layer
com~rising (i) a lig~t-sensitive composition which
comprises at least ~ne light-sensitive com~oun~ or a
li~ht-sensitive comhination oE co~ounds and (ii)
binder material comprising a halogenate~ Polvvin~l
phenol ~om~ound which is insoluble in water but soluble
in aqueous-alkaline solutions; (b) imagewise exposin~
said light-sensitive laYer to actinic radiation; (c)
thereafter washing away the non-i~age areas of said light-
sensitive layer with an aqueous-alkaline developer
solution; an~ ~d) then heating said material
suEEicientlv to harden the remaining image areas of
said light-sensitive layer.
3n Other objects, features, and advantages of
the present invention will become apparent from the
detailed description given hereinafter; it should be
understood, however, that the detailed description and
~5~178~
s~eciic examples, ~hile indicatinq pre~errea embodi-
~ents of the invention, are qiven hy waY of illustra-
tion onl~,7~ since various changes and modifications
within ~he spirit and scope of the invention will
become aPParent to t'nose skille~ in the art ~rom this
detaile~ descrip-tion.
i ~ETAILEn DE~CRIPTION OF PR~FERRED EM~ODIMENT~
._ _ __ _ __ __ _ __ _ _ _~_ _ _ _ _ __ _ __ _
The process of t'~le invention is charac-
terized in that the ~olvvinyl phenol emploved as a
'ninder material is halo~enated.
The halo~enated vinvl phenol polYmers
emPloved are pre~erahlY chlorinated or bro-minated, in
particular brominated, polYmers. Apart from
haloqenate~ homo~olYmerst co~olvmers o~ 'nalogenate~
~invl o'~enols and other vinvl compounds, such as, for
example, styrene or arvlic acid esters, can also be
used. In general, the polYmers o~ p-vinYl phenol are
preferred. The halogen content of the halogenated
polYvin~l phenols usually varies between 20 an~ nn~ bv
1 20 weight, ~re~erably between ~0 and ~8~ by weiqht.
The brominated pol~-p-vinvl phenol is
prepared in a known manner by hrominatinq the
corresponaing p-vinvl phenol polYmer~ ~he polYvinvl
phenols themselves can be pre~ared bv a mass
polymerization, emulsion ~olymerization, or solution
polymerization of the corresponding monomers in the
^
~ ~ 7 ~ 20731-844
~25~7~7
presence of a cationic catalyst. They can, however, also
be obtained by means of a free-radical polymerization in the
presence of suitable catalysts, such as azodiisobutyric acid
nitrile.
Polymerization processes of this kind are described
in "Journal of Polymer Science," part A-l, volume 7 (196g),
pages 2,175 to 2,184 and 2,405 to 2,410, and in "Journal of
Organic Chemistry," volume 24 (1959), pages 1,345 to 1,347.
The concentration of the halogenated polyvinyl phenols
in the light-sensitive mixture can vary widely, depending on
the nature of the light-sensitive system. In general, their
proportion is between 10 and 95% by weight, preferably
between 40 and 80~ by weight, relative to the weight of the
non-volatile constituents of the light-sensitive mixture.
; Futhermore, the light-sensitive mixtures according
to the invention contain a light-sensitive compound or a light-
sensitive combination of compounds. Above all, positive-working
compounds, that is to say, compounds which are rendered soluble
by exposure, are suitable for this purpose. These include
o-quinone-diazides andcombinations of photolyticacid donors
and compounds which can be split by acid, such as orthocarboxylic
acid compounds and acetal compounds. p-Quinone-diazides and
diazonium salt polycondensation products are also suitable as
light-sensitive compounds.
- R - ~ ~ 5 ~787
The mixture an~ Process accordin~ to the
invention have particular advantages le thev are used
in combination with liqht-sensitive materials basefl on
o-quinone-~iazides, since, employin~ these, the num~er
oE Prints ohtained can be particularly considerablY
increasea b~ hakinq. ~uitahle materials o~ this ty~e
are '~nown an~ describe~, ~or example in German Patent
~o. 4~8,233, and in German ~Ffenlegun~sschriften No.
~,~31,377, No. ?,~47,90~, and No. ~,8~8,037. The
pre~erred o-quinone-~ia~i~es are na~hthoquinone-(1,~)-
dia~iae(~)-4- or -~-sulfonic acid esters or amides.
Amongst these, the esters, es~eciallv those o~ the
5-sul~onic acid, are ~articularlv Preferred. In
general, the quantitv of o-quinone-~ia2ide com~oun~s
is ~ to ~0~ by weight, pre~erahly 7 to 3~% bv weight,
relati~Te to the non-volatile constituents o~ t'ne
mixture.
Materials based on compounds w~ich can be
sPlit hv acid can also he baked with qood e~fect and
used in the process accordin~ to the invention.
Co~ying materials of this tYpe are known and
are ~escribed, ~or example, in U.S. Patent No.
; ~,779,778 and No. 4,101,32~, in German Patent No.
2,718,~4, and in German Of~enlequng~sschri~ten No.
~,8~,S12 and No. ~ 9,~11. As the compounds which
can he s~lit hy acid, the a~orementioned cooyin~
materials contain ort'nocar~oxylic acid ~erivatives,
monomeric or pol~meric acetals, enol ethers, or acvli-
minocar~onates. As the compounds which are sensitive
to radiation an~ eliminate acid, the copvin~ materials
predominantlv contain orqanic halo~en compounds, in
particular s-triazines or ~-trichloromethvl~ ,4-
oxadiazoles which are su~stituted by haloqenomethvl
grou~s. ~
. .
~lZ5~7~7
~mong the orthocar~oxvlic aci~ derivatives
aescribe~ in IJ.S. Patent Mo. ~,lnl,323, the
~is-1,3-dioxan-2-yl ethers oE aliphatic ~iols are
Particularly use~l.
Among tlle polYacetals ~escribed in German
Patent No. 2,718,~54, those with alipnatic al~ehvde
units and liol units are preEerre~.
Further, verv suita~le mixtures are
described in ~,erman Of~enlequngsschrift No. 2,928,63~.
In the latter, Poly~eric ortho-esters with recurrent
ortho-ester qrou~s in the main chain are described as
com~ounds which can be split by acid.
These qrou~s are 2-alk~l ethers o~
1,3-dioxa-cYcloalkanes havin~ ~ or ~ rin~ members.
Polymers with recurrent l,~-dioxa-cYclohex-~-vl alkyl
ether unitsl in which the alkYl ether group can ~e
interruPted bY ether oxY~en atoms and is prefera~lY
honded to the 5-position of t~e adiacent rinq, are
articularlY preferred.
The quantitative Pro~ortion o~ the compounds
wnich can ~e sPlit bv acid in tne liq~t-sensitive
~ixture is in general between ~ and 65~ bv weiqht,
Preferahly between 14 and 44~ hv weight, r~lative to
the non-volatile constituents of the mixture. The
quantitv of the compound which eliminates acid is
~etween n.l and 10~ hv weiqht, preferably hetween 0.2
and ~% hv weight.
Along with the haloqenated polyvinvl
~henols, numerous otner resins can he empl~ved in the
light-sensitive mixtures o~ the invention, vinvl polY-
mers, such as polYvinyl acetates, Polyacrvlates~
~s~
-- 10 --
polYvinvl ethers, ~01~l~7inYl acetals, PolYvinvl
pYrroli~ones an~ coPolYmers o~ the monomers on which
these are based ~einq pre~erred. Further suitable
binders ~hich are soluble or swella~le in alkaline
solutions are natural resins, such as shellac an~
colo~honY an~ sYnthetic resins, such as copolYmers o~
stvrene and maleic acid anhyaride,- anA, in partlcular,
novolaks. ~he most advantageolls ~roportion of these
resins ~epends on the technological requirements and
on the in~luence on the ~evelopment con~itions an~, in
general, this is not more than ~0% bv weight of the
haloqenated Polvvinvl Phenol. To meet special
re~uire~ents, such as flexibilitv, a~hesion, qloss,
coloration, color change, and the like, the
liqht-sensitive svstem can aflditionallv also contain
substances, such as ~olyglvcols, cellulose deriva-
ti~7es, such as ethyl cellulose, sur~actants, dyes,
adhesion ~romotors and inelv divided pigments, and
also IrV-absorhers, i~ required.
; 20 For coa~ing a suitable support, the mixtures
are in general dissolved in a solvent. The selection
of the solvents must be matcned to the envisaged
coatin~ Process~ the laver thickness anA the ~rYing
conAitions. Suitable solvents for the mix-ture
accordinq to the invention are ketones, such as methYl
ethYl ketone, chlorinated hy~rocarbons, such as
trichloroethvlene and l,l,l-trichloroethane, alcohols,
such as n-Pro~anolr ethers such as tetrahv~rofuran,
alcohol-ethers, such as ethylene glycol monoethvl
ether, and ester~s, such as hutvl acetate. ~t is also
2~L78~
~ossi'ole to use mixtures which, for sPecial pur~oses,
can contain additional solvents, such a~s acetonitrile,
~i~xane, or ~imethvlformamide. In ~rinciPle, all those
solvents can he used which ~o not irreversihly react
with the laver comPonents.
~ he supports used for laver thicknesses o~
less than about 1~ ~m are in most cases metals. The
following mav be used for offset prinkinq Plates:
brignt-rolled, mechanicallv or electrochemicallY
roughene~ aluminum whic~ esired, i~s anodicallY
oxidize~ and which additionally can also have been
chemicallY pretreated, for e~ample, with Polyvi-
nylphospnonic aci~, silicates, 'nexafluoro~irconates,
hydrolysed tetraethYl orthosilicate, or phos~hates.
Coatinq of t'ne support material is carried
out in a known manner ~v spin-coating, sQraving,
flipping, on rollers, by means of slot ~ies or blade-
sPreadin~, or bv means Oc coater a~plication.
T.iqht sources customarv in in~ustrv are use
for exposure. Irradiation witn electrons or a laser
is another Possibility for Pro~ucinq an imaqe.
The aqueous-alkaline solutions whic~ are
used or ~evelopinq have qraduate~ alkalinitv, that
is, theY have a P'tl whic~ preferably is between ln and
14, an~ thev also can contain minor amounts o~ organic
solvents or surfactants, remove t'nose areas o~ the
coPyinq laver which have been struck ~v li~ht, an~
thus produce a positive imaqe of the oriqinal.
Ne~ative lavers can he ~evelo~ed bv means o~ similar
developerS.
- 12 - ~25~
The preferred use oE the light-sensitive
mixtures accordin~ to the invention is in the prePara-
tin o~ Printing ~orms, in Particular, o~set ~rintin~
~orms, usinq aluminum as the suoport.
~fter development, the ~rintinq orm is
heated in a manner known ~er se. The hakinq tem-
Peratures selected can be in the ran~e ~rom about 180
to 240-', prefera'olv ~rom ~OQ to ?40C, and heating
periods o 1 - 20, ~re~erably ~ to 10, minutes being
normally re~uired. If the supPort material is stable
at higher temperatures it is o~ course also possi'~le
~o bake at hi~her ~emperatures above ~4noc and to
select corres~onainql~7 shorter heatinq ~eriods.
~he mi~ture o~ this invention and the
liqht-sensitive co~yinq material pre~ared t~erqfrom
are distinq~lished by the fact that a~ter haking prac-
tically no remainders due to baking are le~t on the
image-free areas o~ the support. It is therefore no
longer necessarv to apply an additional water-soluhle
protective laver before hakin~, or to remove the
remainders subsequently bv treatment with ~eveloper.
Neit~er ~y means of the known haloqenated
novolaks nor by means o~ the known non-haloqenated
novolaks is this advantaqe achieved. As compared with
non-halogenated polyvinvl Phenol binders, another
advantage ~resented by the use o~ haloqenated
~olYvinyl phenols as binders resides in the ~arkedlv
improved re~istance of the non-baked ~rinting stencil
to auxiliaries used in ~rintinq, such as, ~or exa~ple,
certain hyflrocarbon solvents or alcohol-containing
~25~7~
fountain solutions, which are commonlv emploved durinq
co~vinq or in the ~rinting press.
The invention is explained in greater detail
bv reference to the examples which follow, wherein
parts by weiqht (~.b.w.l and parts by ~olume (P.b.v.)
have the same relationship as the g to the cm3.
Jnless otherwise stated, -oercentages are precent bv
weiqht.
ExamPle 1
An electrochemicallY roughened and
anodicallY oxidized aluminum ~late was coated with a
solution of
1.~ p.b.w. of the esteri~ication product obtained
from 1 mole of 2,3,4-trihydroxv-kenzo-
phenone and ~ moles of napht~oquinone-
(1,2~-diazide-(2)-~-sulfonic aci~
chloride,
h p.b.w. of brominated ~olY-p-vinvl phenol 'naving
a melting range of 190 - 220C, a
bromine content o~ about ~n~, and an
average molecular weiqht oE ~,ono,
0.1~ p,b.w. o~ ~-(4-ethoxv-naphth-1-yl~ 4,fi-bis-
trichloro,nethyl-~-triaæine, and
- 14 - ~2~7~
n.n7 ~.h.~. o~ crvstal violet, in
.
~.b.w. o~ etnvlene ~1YCO1 monometh~l ether and
~0 p.~.w. of tetrahYdrofuran.
~efore application o~ the light-sensitive
co~ving layer, the anodicallv oxidized support ~ad
been treated with an aqueous solution o~ 0.1~ by
weight strenqth Polyvinylphosphonic acid.
The presensitiæed material thus prepared,
which had a laver weight o~ %. n q/m~, was exPosed in
an imagewise fashion under a crans~arent positive ori-
ginal and subsequently develo~ed with an 0.~% strengt~
aqueous solution o~ sodium meta~silicate x 9 H~O.
The areas of the copYinq laYer which had
been struck bv liqht were removed bY the development,
lS an~ the unexposed image areas remained on the support,
~roducin~ a ~rintin~ stencil corresponding to the
original beinq o~tained.
~ n an offset Printin~ ~ress, it was possible
to ohtain 100 ,no~ perfect print~ Fro,n tne Printing
form thus prepared.
In order to extend the print run and to
harden the printing stencil, the Printin~ form was
subJected to a heat treatmenc. ~or this purpose, the
dried ~rinting ~orm, after develo~ment, r~7a~s heated in
a baking oven or 5 minutes to 2~nt`.
As a result oF heating the Drintinq ~orm in
the oven, the ~rinting stencil was hardened and the
L25;~7~7
laYer became resistant to chemicals, such as, -for
examPle~ deletion ~luids, and thus insoluhle in
orqanic solvents, SllCh as acetone, alcohols, toluene
or xvlene.
After the heatinq steP~ the printing sten~il
can be immeaiatelY inXed ~ith ~reasv ink, in the Pre-
sence o~ water, without an ad~itional post-treat~ent
o~ the Drintinq ~orm bein~ re~uired. ~0 ,n~o perfect
prints could be run in an ofset ~rinting press.
The aavantage which the haloqenated
Polvvinvl phenol binders of the invention possess in
liqht-sensi-tive mix-tures over non-halo~enated polv-
vinvl Phenol hinders~ hecomes apparent when the
brominated ~olY-p-vinvl ~henol in Exam21e 1 is
replaced by the corresponding non-brominated
Poly-p-vinyl ~henol. Whereas the printinq stencil
~rePared in accordance with Example 1 is alreadv
resistant to deletion fluids and insoluble in organic
solvents, such as acetone, after a bakina time of only
; minutes at ~30C, tne Printing stencil of a
corresP~nding Drinting form containing the non-
hrominated polY-p-vinyl phenol as the binder is
dissolved bv the deletion fluid, and the laver remains
soluble in acetone, even after a bakin~ time of 10
minutes, under otherwise identical test con~itions.
Even hefore bakin~, the Printing stencil
according to Example 1 exhibits an excellent
resistance to auxiliaries used in Printinq, such as
~ounta ;n solutions, roller cleansinq aqents, or ~late
wash-out solutions. ~hereas the ~rintinq stencil
- lh _ ~Z5~7~
preparPd in accordance with Example l is nat visibly
attacke~ a~ter ~ minutes' action of a ~0~ strenqt~
isoproPanol solution rendered acidic with phosphoric
acid, t~e corres~onding printinq stencil containinq
pol~-p-vinyl Phenol as the binder is alreadv detached
from the support after 15 seconds.
When the hrominated polv-p-vinyl ~henol in
Example 1 is re~laced by t~e same amount o~ a cresol-
~ormal~ehyde novolak or of a brominated cresol-formalde-
hyde novolak havinq a bromine content Oe 3~%, asdescrihed in D~-A 3,107,1~, and the developed
printinq form is ~aked under otherwise identical
conditions at ~30C, then, in contrast to the
corresPonding printin~ form containinq Poly-p-vinvl
hromo~henol as the hin~er, strony ~o?ging ~henomena
apPear in the imaqe-free areas uPon inkin~ with greasY
ink, which cannot be removed.
In the ~xamPles below, further coatinq
solutions are ~escribea, with whicll similar results
were obtained. ~nless other~ise statefl, the Prepara-
tion and Processing o~ t'ne ~rintinq plates o~tained
usinq tnese solutions correspond to the conditions
aescribed in ~xam~le 1.
ExamPle
_ __
An electrochemically roughened and
anodicallY oxidized aluminum Plate~ the surface o~
which na~ been treated with an a~ueous solution o~
. .
- 17 - ~2~7~7
~olyvinvlphosPhonic aci~, ~as coated with a solution
o~
p.h.w~ of the esteri:~ication product ohtained
from 1 mole o~ ,4-trihydroxv-benzo-
Phenone and ~ moles oE naphtho~uinone-
(l,~)-diaziAe-(~ -sulfonic acid
chloride,
4 p.b.w. of the brominated poly-p-vinYl phenol o~
ExamPle 1,
0 ~ o~ . o~ a cresol-~ormaldehyde novolak havinq
a soteninq Point o~ ln~ to 120C,
0.16 p.b.w. of ~ (acenaphth-~-Yl)-4,5-bis-
trichloromethy~-s-triazine, and
n.n7 p.b.w. of crvstal violet, in
~o p.b.w~ of ethvlene glycol monomethvl ether an~
~.b.w. o~ tetra~v~ro~uran.
~ he printing form was exPosed throuqh a
trans~arent ~ositive original and developea with a 1
strenqth aqueous solution of sodium metasilicate.
- 18 - ~2
Exam~le ~
An electrochemicallv roughened and
anodically oxidized aluminum plate was coated with a
solution of
2.4 p.b.w. of a ~0% strenqth solution, in toluene,
o~ a polYortho-ester pre~ared from
- 7,7-bis-hydroxymethyl-~-oxa-nonan-(1)-ol
and trimethvl ortho~ormate
n.2 ~.~.w. of ~-(4-ethoxv-naphth-1-yl)-4,~-his-
trichloromethYl-s-triazine~
p.~.w. of the brominated poly-~-vinyl phenol of
~xample 1, and
.n35 p.h.w. of crystal violet hase, in
~0 p.b.w. o ethvlene ql~col monomethvl ether and
p.~.w. o~ tetrahydrofuran.
The printing plate thus prepared was exPosed
in an imagewise fashion ~or ~0 seconds, at a distance
o~ 110 cm, under a 5 kW metal hali~e lamp and sub-
: sequently developed with the developer solution of
Example 1.
. .
- 19 - ~2~ 7
~xam~le d
An electrochemicallY roughened an~
anodicall~ oxidized aluminum plate was coated with a
solution of
n.~5 ~.b.w. of a oolYacetal prenared from triethY-
lene glycol and 2-ethyl butYraldehyde
0.1 ~.b.w. of 2-(4-ethoxy-naphth-1-yl1-4,6-bis-
trichloromethyl-s-triazine,
~ .w. of the hrominated ~oly-P-vinyl pnenol of
ExamPle 1, and
0.~ p.~.w. of a cresol-formaldehyde novolak having
; a softening point of 105 to 1~0C, and
O.nlh p.h.w. of crvstal violet base, in
20 p.h.w. of ethylene g1YCO1 monomet'nyl ether and
15 20 p.b.W. of tetrah~drofuran.
The printing plate thus prepared was exPosed
in an imagewise fashion for 10 seconds, at a distance
o~ lln cm, under a ~ kW metal halide lamp and
subsequentl~ developed with a 1~ strength aqueous
solution of sodium metasilicate.
