Note: Descriptions are shown in the official language in which they were submitted.
K-23 3 8
PRINTING PLATE PRESENSITIZED WITH AN
O-NAPHTHOQUINONE-DIAZIDE COMPOUND
This invention relates to a printing plate presensitized by means
of an o-naphthoquinone diaæide compound, which plate contains a novo-
lak or a resol resin in its copying layer and includes an aluminum
support with an electrolyticalLy oxidized coated surface, the printing
plate exhibiting an improved adhesion of the copying layer to the oxi-
dized surface of the support.
Printing plates of the above-described type sensitized by means
of o-quinone diazide compounds are known. The adheslon of their resin-
containing copying layers to the electrolyticaLly oxidlzed aluminum sur-
faces is good. Nevertheless, an improvement of the adhesion is s1:ill
desirable, because pnnting forms prepated from such printing plates
yield longer runs. It already has been proposed to further improve the
adhesion between the copying layer and the support in printing plates of
this type by a further treatment of the electrolytically oxidized aluminum
surfaces, but this means that an additional process step is requLred for
the preparation of the printing plate, which increases the cost of the
plate and renders it more difficult to control the manufacturing process.
- It is the object of the present invention to provide a presensitiz-
ed printing plate of the above-described type in which the adhesion of
the copying layer to the oxidized aluminum surface is improved in a
simpler manner. In the presensitized printing plate according to the
presentinvention, the copying layer contains an amino alkoxy silane
compound of the following formula
R - (CH ) - Si - (OR')
2 n I m
.~
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?~ 8
wherein
R is an amino group or an aminoalkyl amino
group with 1 to 4 carbon atoms,
R' is an alkyl group with 1 to 4 carbon atoms, and
R" is either the methyl group or R-(CH2),
and wherein
m is 2 or 3,
n isl, 2, or3, and
p is either 0 or 1, and m and p, taken together, being 3,
- 10 by which the adhesion of the copying layer to the oxidized surface of
the support is improved.
Examples of suitable amino alkoxy silane compounds which may
be present in the copying layer to improve the adhesion between the
copying layer and the support are the following compounds:
!~ aminomethyl triethoxy silane
NH2-CH2-Si- (OC2H~)3
,13-aminoethyl triethoxy silane
NH2-(CH2)2-Si-(OC2H5)3
~-aminopropyl triethoxy silane
NH2-(CH2)3-Si-(oc2H5)3
~-aminopropyl trimethoxy silane
N H2 ~ (CH2) 3 -Si- (OCH3) 3
N-(~-aminoethyl)-~-aminopropyl trimethoxy silane
NH2 CH2-CH2-NH-(CH2)3-Si-(ocH )
The amino alkoxy silane compound contained in the copying layer
is a bi-fun tional compound. Probably, it combines on the one hand
with the oxidized surface of the support and on the other hand with the
novolak or resol, thus improving the adhesion between the copying layer
K- 2 3 3 8
and the aluminum surface, It is assumed that at least part of the amino
alkoxy silane compound improving the adhesion of the copying layer to
the surface of the support is attached to the novolak or resol and to the
surface of the support. The proportion of amino alkoxy silane compound
in the copying layer is very small. It ranges from 0. 3 to 5 per cent by
weight, preferably from 0 . 8 to 1. 5 per cent by weight, based on the
weight of the total quantity of resin contained in the copying layer.
The total ~uantity of resin is composed entirely or substantially
entirely of novolak or resol or of a mixture of novolak and resol. Other
resins, if any, are present in minor quantities only, i.e. not more than
10 per cent by weight, calculated on the total quantity of resin present.
Epoxy resin, pplyvinyl ether, polyvin~l acetate, and polyvinyl acetal
I
are examplary of resins of which only minor quantities may be present~
The printing plates prepared in accordance with the present in-
vention have the advantage that from the printing forms obtained there-
from, longer runs may be obtained until they are worn off than from simi-
lar printing plates containing no amino alkoxy silane compound In the
copying layer. Printing plates containing a dye in the copying layer, in
order that the developed printing image of the printing form obtained is
more visible, have still another advantage, viz. if corrections should
become necessary, the corrected areas of the printing forms obtained
from the printing plates according to the invention have the same appear-
ance as other background areas, whereas in the case of printing forms
made from similar printing plates containing no amino alkoxy silane
compound in the copying layer, the corrected areas differ from the re-
maining background areas~ so that the entire image assumes a mottled
appearance which impedes visual fault control of the printing form. As
compared with other known printing plates of the same type, in which
-- 3 --
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the improved adhesion is produced by an addLtlonal process step, the
prlnting plates according to the invention have the advantage that thelr
manufas~ture is slmpler and can be con-trolled more easlly.
The following examples wlll further lllustrate the lnvention:
Example 1
An eleGtro-chemlcally roughened and anodlzed surface of an
- ~ aluminum foll with an oxide layer welghing about 3 grams pe~ square
meter was whirler-coated wlth a light-sensltlve layer of the following
composition. - The quantities stated are ln per cent by welght, -
6.6% of a novolak ("Alnovol PN 429"),
1.1% of the cumyl phenol ester of naphtl4oquinone-
` - (1, 2) -dlazide- (2) -sulfonic acid- (4),
~. . .
0.6% of 2, 2'-bis~naphthoquinone-(1, 2)-dlazide-(2)-
sulfonyloxy-(5) }dinaphthyl-(l, 1') methane,
0,08% of crystal vlolet,
0,24% of 1, 2-naphthoqulnone-diazide-(2)-sulfo
chloride~
0.066% of y-aminopropyl trlethoxy silane, and
91.314% of a solvent mixture of 80 per cent by weight
; ~ ~ 20 of glycol monomethyl ether and 20 per cent
by weight of butyl acetate,
The coated plate was dried at 120C.
For the preparatlon of an offset prlnting form, the resultlng
printing plate was exposed, developed wlth an alkallne developer, and
then corrected. The plate was then used for prlntlng in an offset ma-
chlne ("Multillth 1850"), As cornpared with a prlntlng form obtained
from a slmilar prlntlng plate whlch contained no amlno alkoxy silane
compound, the length of the run was increased by at least 40%, viz.
159, 000 coples as compared wlth 111, 000 coples.
ale~narl~
K 2338
Example 2
A light-sensltlve offset printlng plate was produced as descrlbed
ln Example 1, using the following formulation:
6.3% of novolak ("Alnovol PN 430"),
1.48% of the condensation product of 2, 3, 4-trihydroxy-
~. !
benzophenone and naphthoqulnone-(l, 2)-dlazlde-
~: (2~-sulfochlorlde-(5),
Q, 7% of 2, 2 ' -bis ~ naphthoquinone- (1, 2~ -dlazlde- (2) -
sulfonyloxy-(5) ~dlnaphthyl-(1, 1')-methane,
- 10 0.3% of a resol resin ("Phenodur PR 897"),
~t ~ ~
~; ~ 0.2% of 1, 2-naphtho~uinone diazlde-(2)-sulfochlorlde,
0.066% of N-(~-amlnoethyl)-7-aminopropyl-trimethoxy-
silane,
.,
0.084% of me-thyl violet, and
90, 8 7% of the solvent mlxture used ln Example 1 .
, ~ A prlnting form was prepared ln the usual manner and used for
prirltlng in an offset machine of the type "Heidelberger offset rll,achine
KOR" . ~ prlnting form containlng no amino alkoxy silane ylelded a run
of 170, 000 copies, whereas a plate containing such an a~ditlon yielded
a run of 260, 000 prints, which corresponds ~o an increase of more than
50 per cent.
Example 3
A light-sensltlve prlnting plate was prepared as descrlbed in
Example 1, using the following formulation:
6.3% of novolak (as ln Example 1),
0.~% of an epoxy resin ("Epikote 1001", a product
of Deutsche Shell Chemle CmbH.),
0,3% of a resol resln (as in Example 2),
r~dema~ ~ 5 _
K-2338
1O48% of the condensation product of 2,3,4~-trihydroxy-
benzophenone and naphthoquinone-(1,2)-
diazide- (2) -sulfonic acid- (5),
0 . 7% of 2, 2' ~bis-[naphthoquinone-(l, 2)-diazide-(2)-
sulEonyl-oxy- (5)~ -dinaphthyl- (1 ,1 ' ) -methane,
0.2% of 1,2-naphthoquinone-diazide-(2)-sulfochloride-(4),
0 . 088% of methyl violet,
O.066% of N-(,B-aminoethyl)-~-aminopropyl-trimethoxy
silane, and
90.466Yo of the solvent mixture used in Example 1.
The printing form obtained from the resulting printing plate was
used :Eor printing on a "Heidelberger GTO" offset machine.
The run obtainable was increased by rou~hly 25%, viz. 225,000
copies as compared with 178,000 copies. ~ I
EXAMPLE 4
The surface of an aluminum foil was first silicated in an alkaline
solution by an electro-chemical process and then anodized, and the re-
sulting plate was then coated, as described in Example 1, wLth a light-
sensitlve layer of the following composition:
6.6% of novolak (as in Example l),
1.1% of the condensation product of 2,3,4-trihydroxy-
benzophenone and naphthoquinone- (1, 2~-diazide-
(2)-sulfonic acid-(5)r
0.55% of 2,2' bis-~naphthoquinone-(1,2~-diazide-(2)-
sulfonyl~oxy- (5)~ -dinaphthyl- (1 ,1 ' ) -methane,
0 . 078% of crystal violet,
O . 24% of 1, 2-naphthoquinone-diazide-(2)-sulfochloride,
K-2 3 3 8
O . 049% of N - (,B-aminoethyl)- ~-aminopropyl-tri-
methoxy silane, and
91.383% of the solvent mixture used in Example 1.
The resulting printing form yielded a run which was increased
by 45%, i . e ., 1 46, 000 copies a s compared with 98, 000 copies .
It will be obvious to those skilled in the art that many modifi-
,~ ,
cations may be made within the scope of the present invention withoutdeparting from the spirit thereof, and the invention includes all such
modification s .
