Note: Descriptions are shown in the official language in which they were submitted.
5~
BACICGROUND OF THE INV13NTION
___~ __,_ ~_________________
1. Field of the Invention
The present invention relates to a photosensitive litho-
graphic printing plate and more particularly, the invention relates
to a lithographic printing plate having a photosensitive layer of
a novel and improved photosensitive diazo-oxide resin.
2. Description of the Prior Art
It is well known to use a photosensitive diazo-oxide in
the production of photocopies or photoresists and also as a
photosensitive rnaterial for litho~raphic printing plates. In
these techniques, as the result of light exposure, due to the
properties of the photosensitive diazo-oxide, a difference in
soluhilit~v between the exposed areas and the unexposed areas~
results and by treating the exposed layer of such a material
with an appropriate solvent, a desired image portion remains on
the support while undesired portions are washed away from the
support. These techniques are described in detail in the specl-
fications of, e.g , U.S. Patent Nos. 3,046,1~1, 3,046,122, and
3,046,123. In the above patents, the ester or acid amide of
benzenediazo-oxide or naphthalenediazo-oxide is used as the
photosensitive material for photosensitive lithographic printing
plates. Other various materials for thls purpose have also been
reported.
~ Iowever, almost all of these compounds are low molecular
weight compounds and when such a compound is used individually for
a photosensitive litho~raphic printing plate, crystallization
occurs, which results in a poor film of the compound being obtained,
and thus the ima~e formed has low mechanical strength~ This makes
it difficult to ohtain many satisfactory copies or prints. There-
fore, the aforeE;aid photosensitive materjal is frequently used
~p~
together with an alkali-soluble reslnous binder or as a compound
formed by the reaction thereof with an alkali-soluble resinous
material.
Such polymers are described in the specifications of
United States Patent Number 3,046,120, British Patent Number
1,113,759, and United States Patent Number 3,759,711. The
compounds described in these specifications are mainly
polymers such as phenol resins and aminostyrene resins.
However, although these compounds may have good sensi-
tivity and provide sufficient difference in solubility between
the exposed areas and the unexposed areas, they have the dis-
advantages that coated layers of these compounds are brittle and
have a comparatively poor flexibility.
SUMMARY OF THE INVENTION
An object of this invention is, therefore, to provide
a photosensitive lithographic printing plate having a layer of
a photosensitive diazo-oxide resin without the above-described
disadvantages.
Another object of this invention is to provide a stab]e
photosensitive lithographic printing plate having a layer of a
photosensitive diazo-oxide resin comprising a polymer in which
a diazo-oxide compo~nd, which is a photosensitive group, is
bonded, as a side chain, to the main chain of a homopolymer or
copolymer of hydroxystyrene.
Still another object of this invention is to provide a
photosensitive lithographic printing plate having a photosensitive
layer having a large difference in solubility in a developer
between the exposed portions and the unexposed portions thereof.
A further object of this invention is to provide a
photosensitive lithographic printing plate having a long press
life and high sensitivity.
As the results of various investigations on attaining
the above-described objects of this invention, the photosensitive
lithographic printing plate of this invention has been obtained.
That is to say, according to the present invention there is
provided a photosensitive lithographic printing plate comprising
a support having thereon a layer of a photosensitive diazo-oxide
resin containing a hydroxystyrene unit and a hydroxystyrene unit
having an o-quinonediazide group bonded thereto through the oxygen
atom of hydroxystyrene.
1~ Also, according to another embodiment of this invention
there is provided a photosensitive lithographic printing plate
comprising a support having thereon a layer of a photosensitive
composition comprising a photosensitive diazo-oxide resin and an
alkali-soluble resin, the photosensitive diazo-oxide resin con-
taining a hydroxystyrene unit and a h~droxystyrene unit having
an o-quinonediazide group bonded thereto through the oxygen atom
of hydroxystyrene.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
__,____________________________._____________. _
Figure 1 is a schematic cross sectional view showing
an embodiment of the photosensitive lithographic printing plate
of this invention.
Figure 2 is a cross sectional view of the photosensitive
lithographic pxinting plate shown in Figure 1 after exposure.
Figure 3 is a cross sectional view of the photosensitive
lithographic printing plate shown in Figure 2 after development~
DETAILED DESCRIPTION OF THE INVENTION
_____________________________________
The lithographic printing plate of this invention
comprises a support ~ith a hydrophilic surface having thereon a
photosensitive layer mainly comprising a specific photosensitive
diazo-oxide resin.
The support used in this inven~ion is a dimensionally
stable support such as a sheet or plate and various kinds of
supports which have hitherto been used for printing plates can
be used in this invention. Examples o~ such supports include
paper, a paper coated with a polymer (such as polyethylene,
polypropylene, polystyrene, etc.); a plate or a sheet of a metal
such as aluminum, an aluminum alloy, zinc, copper, etc.; a film
of a polymer such as cellulose diacetate, cellulose triacetate,
cellulose propionate, cellulose butyrate, cellulose acetate
butyrate, cellulose nitrate, polyethylene terephthalate, poly-
~thylene, polystyrene, polypropylene, polycarbonate, polyvinyl
acetal, etc~; a paper or a polymer film having coated or vacuum
deposited thereon a metal as described above.
Of these supports, an aluminum support is dimensionally
stable, is inexpensive, and is particularly preferred. Further-
more, a composite sheet of a polyethylene terephthalate film
having an alum;num sheet bonded thereto is also preferred as a
support.
Particularly,~ the surface of the support must be hydro-
philic and various methods are known for rendering the surface
hydrophilic.
For instance, for a support with a polymer surface,
surface treatments such as a chemical treatment, a corona dis-
charge treatment, a flame treatment, an ultraviolet treatment,
a high frequency wave treatment, a glow discharge treatment, a
laser treatmentr etc., (as described in the specifications of
U.S. Patent Nos. 2,764,520, 3,497,407, 3,145,242, 3,376,208,
3,072,483, 3,475,193 and 3,360,448 and the speci~ication of
1 British Patent No. 7g8,365) can be used and a method where the
surface is subjected to the aforesaid suxface treatment and then
a subbing layer is formed on the treated surface of the polymer
layer can be employed. A suitable subbing layer comprises a
coating of a 1~ by weight acrylic acid aqueous solution or a
coating of polyvinyl alcohol onto a grained aluminum plate, which,
when washed, provides a hydrophilic coating. A diazo resin layer
is then coated thereon. Suitable examples of subbing layers are
disclosed in British Patent 918,599 and U.S. Patent 3,064,562.
Various approaches have been used for forming a subbing
layer on the polymer surface. For ins-tance, a double layer method
in which a hydrophobic resin layer which adheres well to the poly-
mer surface and has good solubility is formed on the polymer
surface as a first layer and then a h~drophilic layer is formed
as a second layer and a single layer method in which a layer of
a polymer havin~ a hydrophobic group and a hydrophilic group in
the same molecule is formed on the polymer surface have been used.
~ lso, in the case of a support having a metallic surEace,
in particular, the surface of aluminum, preferably the surface of
the metallic layer or support has been subjected to a graining
treatment~ an immersion treatment in an aqueous solution of
sodium silicate, potassium fluorozirconate, a phosphate, etc.,
or an anodic oxidation treatment. Also, an aluminum plate which
is grained and immersed in an aqueous solution of sodium silicate
as described in the specification of U.S. Patent No. 2,714,066
and an aluminum plate which is subjected to an anodic oxidation
treatment and then immersed in an aqueous solution of an alkali
metal silicate as described in the specification of U.S. Patent
No. 3,181,~61 can be used appropriately in this invention~ The
above-described anodic oxidation treatment can be conducted by
_ 5 _
Y placing the aluminum plate in an electrolyte of an aqueous solu-
tion or a non-aqueous solution of an inorganic acid such as
phosphoric acid, chromic acid, sulfuric acid, boric acid, etc.,
an organic acid such as oxalic acid, sulfamic acid, etc., or a
salt thereof or of a combination of these solutions and an
electric current is passed using the aluminum plate as the anode.
Moreover, the electrodeposition of silicate as described
in the specification of ~.S. Patent No. 3,658,662 can be effect-
ively employed for the surface treatment of an aluminum layer or
1~ sheet.
The above-described surface treatment is employed, in
addition to rendering surface of a support hydrophilic, to prevent
the occurrence of any harmful reactions with the photosensitive
composition formed thereon and to improve the adhe:rence between
the support surface and the photosensitive layer formed thereon.
In particular, however, when aluminum is used as the support,
the surface thereof has sufficient hydrophilic property without
the necessity oE any surface treatment to render the surface
hydrophilic and hence the surface treatment as described above
is applied to the surface o the aluminum support mainly for
preventing the occurrence of any harmful reactions with the
photosensitive composition and improving the adherence between
the support surface and the photosensitive layer formed thereon.
The photosensitive diazo-oxide resin used in this
invention contains at least a hydroxystyrene unit and a hydroxy-
styrene unit having an o-quinonediazide group bonded thereto
through the oxygen atom of the hydroxystyrene. Examples of such
a resin are those containing therein structural units represented
by the following general formulas (I) and (II)
--~CH2-CH ) X ( C~2-CH~
OH
Xl 1
-~-C 2 )x ~ 2 ~
OH
X CH2
Rl CH--OH
C 2 2
wherein X represents a connecting group such as a sulfonyl group
~ .
-~ S ~- , or a carbonyl group ( C ~--, etc.; Rl represents an
o
aromatic o-quinonediazide group such as 1,2-benzoquinonediazide,
1,2-naphthoquinonediazide, 3,3',4,4'-biphenyl-bis-quinonediazide,
2,3-phenanthrenequinonediazide, etc., in which the o-quinone-
diazide group can have a substituent on the aromatic nucleus,
for instance, an alkyl group (e.g., having generally l to 8
carbon atoms such as a methyl group, an ethyl group, a propyl
group, a butyl group, an amyl group, a hexyl group, a heptyl
group, an octyl group, etc.) or an alkoxy group (e.g., having
generally l to 8 carbon atoms such as a methoxy group, an ethoxy
group, a propoxy group, a butoxy group, an amyloxy group, a
~V61~
1 hexyloxy group, a heptyloxy group, an octyloxy group, etc.);
and R2 represents an alkyl group (e.g., having l to 4 carbon
atoms), an aryl group (e.g., a phenyl group, a tolyl group, a
xylyl group, a naphthyl group, etc.3, or a substituted aryl
group and further R2 can include a quinonediazide group substi~
tuted witll an alkyl or aryl group if the photodecomposition of
the quinonediazide is not affected by such a substituent. Here-
inafter, for brevity, the compound containing therein structural
units of the general formula (I) is designated "compound of the
i general formula (I)" and the compound containing therein struc-
tural units of the general formula (II) is designated "compound
of the general formula (II)".
The molecular weight of the compound of the general
formula (I) can range from ahout l,000 to about 30(),000, pre-
ferably from 3,000 to lO0,000, x and y each represents the molar
proportions of the components designated and x/x+y is from about
0 05 to 0.5, preferably from 0.1 to 0.4.
The compound of the general formula (I~ can be pre-
pared using, for instance, the following polymerization reaction.
That is to say, poly(p-hydroxystyrene) which becomes the main
chain of the polymer and an acid halide of a diazo-o~ide to be
reacted, such as, for instance, quinonediazidosulfonyl chloride,
quinonediazidocarbonyl chloride, etc., are uniformly dissolved
in a common solvent such as dioxane, tetrahydrofuran, acetoner
etc., and then the reaction, generally at about -10C to ~0C,
preferably 20C to 40C, is conducted by adding, for instance,
sodium carbonate, sodium bicarbonate, potassium carbonate,
potassium bicarbonate, pyridine, etc., to the solution as a base,
generally in an amount substantially equivalent to the quinone-
diazido acid halide. A suitable molax ratio of the acid halide
to the poly-(p-hydroxystyren~ is about 0.1 to 1 equivalent, pre-
ferably 0.2 to 0.8 equivalent, per hydroxyl group equivalent.
Then, by purifying the reaction mixture thus obtained by a re-
crystallization method, the photosensitive diazo-oxide resin
of this invention is obtained. The poly-(p-hydroxystyrene) can
be prepared in accordance with the disclosure in J. Poly. Sci.
A-l, 7, 2175 ~ 2184 (1969~ and ibid., 7, 2405 ~ 2410 (1969).
The molecular weight of the compound shown by general
formula (II) can range from about 1,000 to about 300,000, pre-
ferably from 3,000 to 100,000. Also, x, y and z each represents
the molar proportions of the components designated and the ratio
x/xfy~z is from about 0.05 to 0.5 and the ratio y/x+y-~z is from
about 0.05 to 0.2.
The compound of the general formula (II) can be prepar~d
in the following manner. That is to say, poly-(p-hydroxystyrene)
which is also used as a starting material in the production of
the compound of general formula (I) is first reacted with a
glycidyl ether such as phenylglycidyl ether in a solvent such
as acetone, tetrahydrofuran, methyl ethyl ketone, dioxane, etc.,
preferably methyl ethyl ketone, in the presence of triethylamine,
1,4-diazabicyclo[2,2,2]octane etc., in an amount of about 0.005
to 0.1 g, preferably 0.01 to 0.2 g, per g of the poly-(p-hydroxy-
styrene), e.g., at about -10C to 80C, preferably 20C to 40C,
particularly preferably at reflux, to form the polymer containing
therein structural units represented by the following general
formula (III)
_ g _
( CH2-CH )x ( C 2 1 ~
(III)
OH o
CH2
Cll CH2 0 ~
I
OH
wherein x and y are as described above.
Then, by reacting the polymer of general formula (II~)
thus formed with the acid halide of a diazo-oxide as in the case
of producing the compound of general ormula (I) and under the
conditions as described above, th~ compound of general formula
~II) is obtained. Alkyl substituted glycidyl ethers and alkyl
substituted phenyl glycidyl ethers in which the alkyl moiety has
1 to 4 carbon atoms can also be used as a starting material in
the above procedures.
In the above-described processes of producing the photo-
sensitive diazo-oxide resin of this invention, polyhydroxystyrene
is used as the starting material but in place of such a compound,
a copolymer of hydroxystyrene and a monomer not having a group
with which the o-quinonediazide and the photodecomposition pro-
duct thereof reacts can also be used as the starting material.
Examples of such a copolymerizable comonomer for the copolymer
are phthalic anhydride, styrene, acrylonitrile, an acrylic acid
ester, and a methacrylic acid ester.
The photosensitive diazo-oxide compound of this inven-
tion can be used individually as a photosensitive layer of the
photosensitive lithographic printing plate of this invention but
it is more preferable to use the compound together with an
-- 10 --
alkaline solution-soluble resin as a binder therefor. Preferred
examples of such an alkali-soluble resin are phenol formaldehyde
resins, cresol resins, styrene-male;c anhydride copolymers, and
shellac. A suitable molecular weight range for the phenol-form-
aldehyde resins and the cresol resins can ran~e from about 2,000
to 50,000, preferably 4,000 to 10,000, and for the styrene-maleic
anhydride copolymer can range from about 5,000 to 20,000, pre-
ferably 8,000 to 14,000. Such a resin is soluble in an alkaline
solution, has high adhesivity to support, and provides desirable
1~ effects in printability. Examples of such resins are disclosed
in Synthetic Resins_in Coating, H.P. Preuss Noyes Development
Corp., Pearl River, New York (1965).
In using the mixture of the photosensitive diazo-oxide
compound of this invention and the alkaline solution-soluble
binder resin, a suitable propo~tion of the photosensitive diazo-
oxide is more than about 20~ by weight. If the proportion of
the photosensitive diazo-oxide is less than about 20% by weight
of the mixture, difficulties in development occur providing images
which are not sufficient and hence good prin-ts are not obtained.
XO Furthermore, by incorporating the various additives as
described hereinafter in the photosensitive layer of the photo-
sensitive lithographic printing plate of this invention, the
printing plate can be provided with desired specific properties.
For instance, in order to obtain visible images by light exposure
and development of the photosensitive lithographic printing plate,
a dye can be incorporated in the photosensitive layer of the
printing plate. Suitable examples of appropriate dyes which can
be used for this purpose include C.I. 26,105 (Oil Red RR), C.I.
21,260 (Oil Scarlet ~308~, C.I. 74,350 (Oil Blue), C.I. 52,015
(Methyl Blue), C.I. 42,555 (Crystal Violet), etc. Such a dye
-- 11 --
1 can be incorporated in the photosensitive layer in an amount
which provides a suf~iciently clear contrast between the color
of the hydrophilic surface of the support exposed by light-exposure
and development o~ the photosensitive layer of the photosensitive
lithographic printing plate and the color of the remaining portions
of the photosensitive layer and, in general, it is appropriate to
incorporate the dye at a level of less than about 7% by weight to
the total amount of the photosensitive composition ~or forming the
photosensitive layer.
~ Also, the photosensitive composition can contain a
plasticizer for imparting the desired flexibility to the photo-
sensitive layer formed on the support. Examples of effective
plasticizers which can be used for this purpose are phthalic acid
esters such as dimethyl phthalate, diethyl phthalat:e, dibutyl
phthalate, diisobutyl phthalate, dioctyl phthalate, octylcapryl
phthalate, dicyclohexyl phthalate, ditridecyl phthalate, butyl-
benzyl pht-halate, diisodecyl phthalate, diaryl phthalate, etc.;
glycol esters such as dimethylglycol phthalate, ethylphthalylethyl
glycolate, meth~lphthalylethyl glycolate, butylphthalylbutyl
glycolate, triethyleneglycol dicaprylic acid ester, etc.;
phosphoric acid esters such as tricresyl phosphate, triphenyl
phosphate, etc.; aliphatic dicarboxylic acid esters such as
diisobutyl adipate, dioctyl adipate, dimethyl sebacate, dioctyl
azelate, dibutyl maleate, etc.; polyglycidyl methacrylate; citric
acid triethyl ester; glycerin triacetyl ester; and butyl laurate.
~ he plasticizer is usually employed in an amount of
less than about 5% by weight to the total amount o~ the photo-
sensitive composition.
Also, in order to obtain visible images i-mmediately
by exposing the photosensitive lithographic printing plate of
this invention, the following spiropyran compounds which are
discolored by light exposure can be incorporated in the photo-
sensitive compositions as described in the specification of
British Patent No. 1,154,716. Suitable examples include 6-nitro-
ben70indolinospiropyran, 1,3,3-trimethylindolino-8'-methoxy-6'-
nitrobenzospiropyran, 6'-nitro-1,3,3-trimethy]indoline benzospiro-
pyran, 1,3,3-trimethylindolinobenzospiropyran, 1,3,3-trimethyl-
indolino-~-naphthospiropyran, xantho-~-benzospiropyran, 6'-nitro-
1,3,3-trimethylspiro(indoline-2,2'-2'H-chromene), 6',8'-dichloro-
l,313-trimethylspiro(indoline-2,2'-2'~-chromene), etc. A suitahle
amount of the spiropyran compound is ahout 2 to 20% by wei~ht to
the total amount of the photosensitive composition.
The photosensitive composition containing the photo-
sensitive diazo-oxide compound of this invention together with,
if desired, the above-described additives is coated on a support
having a hydrophilic surface as a solution or a dispersion in an
appropriate solvent. Examples of the solvent which can be used
for this purpose are organic solvents such as ketones, e.g.,
methyl ethyl ketoner acetone, methyl isobutyl ketone, etc.;
ethyleneglycol monoalkyl ethers, e.g., ethyleneglycol methyl
ether, ethyleneglycol monoethyl ether, etc.; ethers, e.g., dioxane,
tetrahydrofuran, etc.; and a mixed solvent thereof, such as
ethylene dichloride and methyl cellosolve acetate. When the
photosensitive composition is coated as a solution thereof, pre-
ferably the concentration of the composition in the solution is
about 1 to 50~ by weight, preferably 4 to 20% by weight.
The coating composition can be coated using conventional
methods such as, for instance, dip coating, air knife coating,
bead coating, curtain coating, and also extrusion coating using
the hopper as descrihed in the specification of U.S. Patent ~o.
2,68],294.
- 13 -
The amount of the photosensitive layer coated on a
support generally ranges from about 0.1 g/m2 to about 5 g/m2 but
the amount of the photosensitive layer suitable for obtaining
from about 10 to 10,000 good copies ranyes from about 1.0 y/m2
to about 3.5 g/m . If particular care is taken, however, in
making the printing plate or in printing, about 5,000 good copies
can be obtained with a coated amount of as low as about 1 g/m2.
If a longer press life is required, the coating composition pre-
ferably is coated in an amount of about 3.5 g/m2. In this case,
a considerable amount of exposure is required at image exposure
o~ the photosensitive layer.
The photosensitive lithographic printing plate of this
invention is exposed to active light, such as a carbon arc lamp,
a mercury lamp, a xenon lamp, a tungsten lamp, etc~, and then
the exposed portions of the photosensitive layer are removed by
proc~ssing the plate with a developer, whereby the hydrophilic
surface of the support is uncovered at the portions removed.
Suitable developers for the photosensitive lithographic
printing plate of this invention basically include conventional
alkaline solutions which have hitherto been used as developers
for a photosensitive layer comprising a photosensitive diazo-
oxide compound. Such alkaline solutions can suitably have a pH
of about 9.5 to 12. For instance, an aqueous solution of an
alkali such as sodium hydroxide, potassium hydroxide, sodium
silicate, potassium silicate, sodium tertiary phosphate, sodium
primary phosphate, sodium carbonate, potasslum carbonate, etc.,
or an aqueous solution of a basic solvent such as ethanolamine
is used. These alkaline aqueous solutions as described above
can be used individually or as a mixture thereof. Furthermore,
if desired, the alkaline aqueous solution can further contain
ertain organic solvents, for instance, benzyl alcohol, 2-butoxy-
ethanol, 2-metho~yethanol, n-propanol, etc., in an amount of less
than about 10~ by weight, preferably about 1 to 2% by weight.
By using a small amount of the organic solvent as indicated above,
the speed of the development can be remarkably increased.
Furthermore, if desired, the developer can contain a
wetting agent (e.g., a surface active agent). Examples of pre-
ferred wetting agen~s include compounds having mor~ than 6 carbon
atoms, each having a hydrophilic group such as a hydroxyl group,
a carboxyl group, a sodium carboxylate group, a sulfo group, a
sodium sulfonate group, and an alkyleneoxy group. Such wetting
agents are well known as anionic surface active agents and non-
ionic surface active agents. Examples of anionic surface active
agents which can be used as a wetting agent in the developer
are long chain alcohol (e.g., having about 8 to 22 carbon atoms)
sulfuric acid esters, aliphatic alcohol phosphoric acid esters,
sulfonates of dibasic aliphatic acid esters, aliphatic amido-
sulfonates, etc~
Examples of nonionic surface active agents are polyoxy-
29 ethylene alkyl ethers, polyoxyethylene alkyl esters, sorbitanalkyl estersl polyoxypropylene ethers, polyoxyethylene ethers,
etc. Specific examples of these surface active agents are
described in Kaimen Kasseizai Binran (Handbook of Surface~Active
Agents), published by Sangyo Tosho K.K. in 1961.
Specifically preferred wetting agents used in this
invention are DUPONOL ME (the trade mark of the sodium salt of
lauryl alcohol sulfate made by E.I du Pont de Nemours ~ Co.),
*
MONOGEN Y-100 (the trade mark of sodium lauryl sulfate made by
Daiichi Kogyo Seiyaku K.K.), the sodium salt of octyl alcohol
sulfuric acid ester, the ammonium salt of lauryl alcohol sulfuric
* Trade Mark
1,~,,
acid esterr the sodium salt of xylenol sulfuric acid Pster,
DUPONOL LS (the trade mark of the sodium salt of oleyl alcohol
sulfuric acid ester made by E.I. du Pont de Nemours ~ Co ~, the
monosodium salt of N,N~dihydroxyethylglycine, and the like. Of
these compounds, the sodium salt of lauryl alcohol sulfuric acid
ester is most preferred. These surface active agents can be
used individually or as a combination of two or more compounds.
Also, the amount of the surface active agent can vary but generally
the surface active agent is used at about 0.005 to 30% by weight,
preferably 0.5 to 10% by weight, most preferably 4 to 8~ by
weight of the developer.
The development is conducted by contacting the image
exposed photosensitive layer of the photosensitive lithographic
printing pla~e of this invention with the developer as described
above. The contact can be used in various methods such as, for
instance, immersion, spraying, etc.
After contacting the photosensitive layer and the
developer for 60 to 180 seconds, the surface of the printing
plate is softly rubbed using an appropriate brush, absorbent
cotton, etc., whereby only the exposed portions of the photo
sensitive layer are removed. In order to conduct development
more effectively, the exposed surface preferably is processed
with a developer at a temperature higher than about room temper-
ature (about 20 ~ 30C), for instance, at about 40 to 50C.
To further clarify the invention, the invention will
be explained additionally by referring to the accompanying
drawings.
In an embodiment of the photosensitive lithographic
printing plate of this invention as illustrated in Figure l, a
photosensitive layer 2 mainly consisting of the novel diazo-oxide
* Trade Mark
- 16 -
1 compound of this invention is formed on a support 1, such as an
aluminum support, having a hydrophilic surface.
By image exposing the photosensitive lithographic
printing plate showh in Figure 1, the exposed portion 2a becomes
alkaline solution-soluble as shown in Figure 2.
~ he state of the image exposed photosensitive layer
after development is shown in Figure 3 as a cross sectional viewO
As shown in Figure 3, the exposed portions 2a of the photosensi-
tive layer 2 have heen removed and the hydrophilic surface of the
support 1 has been uncovered there. The uncovered surface of the
support is hydrophi]ic and oleophobic. On the other hand, the
unexposed portions 2b of the photosensitive layer 2 remain on
the support after development and the surface thereof is oleo-
philic and hydrophobic. Thus, a printing plate is obtained.
In the present invention, by using the novel photo-
sensitive diazo-oxide compound, a photosensitive lithographic
printing plate having high sensitivity and exhibiting excellent
printability is obtained. Furthermore, the lithographic printing
plate of this invention is supexior in ink-receptivity and the
control of fountain solution in printing becomes quite simple
in the case of using the printing plate made from the photo-
sensitive lithographic printing plate of this invention. More-
over, the lithographic printing plate of this invention is stable
to the passage of time.
Thus, by using the lithographic prinJcing plate of this
invention, very excellent copies are obtained.
The invention will be described further by reference
to the following examples. Unless otherwise indicated herein,
all parts, percents, ratios and the like are by weight.
3~
- 17 -
SYNTEIESIS EXAMPLE 1
27 g of naphthoquinone-1,2-diazido-5-sulfonyl chloride
and 12 g of poly-(p-hydroxystyrene) haviny a mean molecular weight
of 4,770 were dissolved in 100 mQ of tetrahydrofuran at room
temperature. While stirring the solution, ~0 g of an aqucous
solution of 13% by weight sodium carbonate was added dropwise to
the solution at 30C over a period of 45 minutes. After distil-
ling off excess tetrahydrofuran under reduced pressure, 100 mQ
of the reaction mixture was added to about 1 Q of water followed
by stirring vigorously, whereby yellow precipitates were formed.
The precipitates were recovered by filtration, washed with water
several times, and dried at room temperature under reduced
pressure to provide 21 g of the photosensitive diazo-oxide resin.
SYNTHESIS EXA~IPLE 2
.
18 g of poly-(p-hydroxystyrene), 1 mQ of triethylamine,
and 2.3 g of phenylglycidyl ether were reacted in 120 mQ of methyl
ethyl ketone under refluxing for 8.5 hours. Thereafter, methyl
ethyl ketone was distilled off under reduced pressure, the solid
obtained was recovered and dissolved in about 100 mQ of methanol.
Then, the solution was added to about 750 mQ of water, whereby
precipitates were formed. The precipitates were reco~ered by
filtration and dried under a reduced pressure to obtain 17 g of
a resin. 15 g of this resin was reacted with 27 g of naphtho-
quinone-1,2-diazo-5-sulfonyl chloride in the same manner as
described in Synthesis Example 1 to provide 22 g of the photo-
sensitive diazo-oxide resin.
EXAMPLE 1
~ ne part by weight of the photosensitive diazo-oxide
resin prepared in Synthesis Example 1 described above, 2 parts
- 18 -
1 by weight of a novolak-type phenol resin (a phenol-formaldehyde
(1:0~8 molar ratio) condensation product obtained under acid
conditions; molecular weight about 1,200 to 1,500), and 0.02
parts by weight of a dye, Oil Blue, were uniformly dissolved in
30 parts by weight of a mixed solvent of 12 parts by weight of
ethylene dichloride and 18 parts by weight of methyl cellosolve
acetate. The coating composition thus prepared was coated on an
aluminum plate of a thickness of 0.24 mm, the surface of which
had been grained using a rotary coating machine and dried. The
1~ coated amount was 3.1 g/m~ on a dry basis.
The photosensitive lithographic printing plate thus
obtained was exposed behind a transparent positive image to a
Plano PS light (3.5 amperes, using a metal halide lamp) made by
Fuji Photo Film Co., Ltd., at a distance of 1 meter from the
light source for 40 seconds and after immersing the exposed plate
in a developer containing 5~ by weight anhydrous sodium silicate
for one minute at 25C, the surface of the lithographic printing
plate was softly rubbed, whereby the exposed portions were removed
and a positive image of the original was obtained.
When the pxinting plate thus obtained was mounted on a
rotary printer and used for printing, 50,000 good copies were
obtained.
EXAMPLE 2
Three parts by weight of the photosensitive lithographic
printing plate prepared in Synthesis E~ample 1 and 0.02 parts by
weight of a dye, Oil Blue, were uniformly dissolved in 30 parts
by weight of a mixed solvent of 12 parts by weight of ethylene
dichloride and 18 parts by weight of methyl cellosolve acetate.
The coating composition was coated on an aluminum plate of a
thickness of 0.3 mm, which had been subjected to graining using
- 19 ~
a rotary coatin~ machine. In this case the coated amount was
2.6 g/m2 on a dry basis.
The photosensitive lithographic printing plate thus
obtained was exposed behind a transparent positive image to a
Plano P5 Light made by Fuji Photo Film Co., Ltd., as a light
source for 3 minutes with a distance of 1 meter from the light
source as in Example 1 and after immersing the exposed plate
in a developer containing 5% by weight anhydrous sodium silicate
for one minute at 25C, the surface of the plate was softly
1~ rubbed, whereby the exposed portions were removed and a good
printing plate was obtained.
When the printing plate was mounted on a rotary printer
and used for printing, 45,000 good copies were obtained.
EXAMPLE 3
One part by weight of the photosensitive diazo-oxide
resin prepared in Example 2, 2 parts by weight of a novolak-type
phenol resin, and 0.02 part by weight of a dye, Oil Blue, were
uniformly dissolved in 30 parts by weight of a mixed solvent of
12 parts by weight of ethylene dichloride and 18 pcrts by weight
of methyl cellosolve acetate. The coating composition thus pre-
pared was coated on an aluminum plate of a thi~kness of 0.3 rnm,
which had been subjected to graining using a rotary coating
machine and dried. The coated amount was 2.4 g/m2 on a dry basis.
The photosensitive lithographic printing plate was
exposed behind a transparent positive image to the light source
as described in Example 1 with a distance of 1 meter from the
light source for 40 seconds and after irnmersing the exposed plate
for one minute in a developer of 15 parts by weight of butyl
cellosolve, 1 part by weight of sodium primary phosphate, 7.5
parts by weight of sodiurn tertiary phosphate, 10 parts by weight
- 20 -
of polyvinyl pyrrolidone K-15 (made by General Aniline and Film
Corp.), 2 parts by weight of Monogen Y-100 ~trade name, made by
Daiichi Kogyo Seiyaku K.K.), and 200 parts by weight of water,
the surface of the plate was softly rubbed to provide a printing
plate having excellent positive image.
When the printing plate thus obtained was used for
printing on a rotary printer, 50,000 good copies were obtained.
EXAMPLE 4
_
Three parts by weight of the photosensitive diazo-oxide
resin prepared in Example 2 and 0.02 part by weight of a dye,
Oil Blue, were dissolved in 30 parts by weight of a mixed solvent
of 12 parts by weight of ethylene dichloride and 18 parts by
weight of methyl cellosolve acetate and the coating composition
was coated on an aluminum plate, which had been subjected to
graining using a rotary coating machine so that the coated amount
was 2.3 g/m on a dry basis.
The photosensitive lithographic printing plate was
exposed behind a transparent positive image to a Plano PS Light
made by Fuji Photo Film Co., Ltd. with a distance of 1 meter
from the light source for 3 minutes and after immersing the
exposed plate for 1 minute in a developer having the same compo-
siticn as described in Example 3, the plate was softly rubbed to
provide a printing plate having a good positive image.
When the printing plate thus obtained was used for
printing on a rotary printer, 50,000 good copies were obtained.
While the invention has been described in detail and
with reference to specific embodiments thereof, it will be
apparent to one skilled in the art that various changes and
modifications can be made therein without departing from the
spirit and scope thereof.
