Planographic printing

Details Planographic printing Planographic printing

2001-09-05

2004-07-20

Huff, Mark F. (Department: 1752)

Radiation imagery chemistry: process, composition, or product th

Imaging affecting physical property of radiation sensitive...

Making printing plates

C430S303000, C430S270100, C430S271100, C430S281100, C430S328000, C430S909000, C430S911000, C430S905000, C101S453000, C101S454000, C101S456000, C101S457000, C101S458000, C101S465000, C101S466000, C101S467000

Reexamination Certificate

active

06764807

ABSTRACT:

This invention relates to planographic printing and provides a planographic printing member precursor, a method of preparing a planographic printing member and such a printing member per se.
Planographic and/or lithographic processes involve establishing image (printing) and non-image (non-printing) areas on a substrate, substantially on a common plane. When such processes are used in printing industries, non-image areas and image areas are arranged to have different affinities for printing ink. For example, non-image areas may be generally hydrophilic or oleophobic and image areas may be oleophilic. In “wet” lithographic printing, a dampening or fountain (water-based) liquid is applied initially to a plate prior to application of ink so that it adheres to the non-image areas and repels oil based inks therefrom. In “dry” printing, ink is repelled from non-image areas due to their release property.
There are numerous known processes for creating image and non-image areas. Some processes rely on the differential solubility of exposed and non-exposed areas in a developer; others use incident radiation to break covalent bonds of radiation sensitive formulations or to ablate a layer of material.
It is an object of the present invention to provide a novel planographic printing member precursor and/or method of preparing the same and/or method of preparing a printing member and/or such a printing member per se.
According to the present invention, there is provided a planographic printing member precursor comprising a first component and a second component, said first and second components being arranged to interact in areas exposed to imaging radiation for providing a surface having a first affinity for ink and one of either said first or second components being removable in non-exposed areas for providing a surface having a second affinity for ink different to said first affinity.
Suitably, only one of either said first or second components is removable in non-exposed areas. Preferably, said surface having a second affinity for ink is arranged to be defined, at least in part, by said first or second component which is not removable in non-exposed areas.
Said surface having a first affinity for ink is preferably relatively hydrophilic and/or oleophobic. Said surface having a second affinity for ink is preferably relatively oleophilic.
Said first and second components preferably include respective first and second functional groups or precursors thereof which are arranged to interact, especially to react, with one another for the formation of covalent bonds between the first and second components. Preferably, prior to said interaction said first and second components are not covalently bonded to one another. Thus, imaging radiation suitably does not break any covalent bonds between said first and second components.
Preferably, said first component includes a functional group or a functional group precursor capable of undergoing a condensation reaction with a functional group of said second component. The term “functional group precursor” includes a reference to a functional group which can be converted to another group or moiety in situ which can react as described. Said first component preferably includes one or more hydroxy groups. Said first component preferably comprises a polymer having hydroxy groups. Said polymer may comprise an inorganic polymer, for example a glass or an organic polymer for example a resin such as a phenolic resin and/or a resole resin and/or an epoxy resin and/or a hydroxypropylcellulose and/or a polyvinyl butyral and/or a polyvinyl alcohol.
Said first component preferably includes an oleophilic and/or hydrophobic moiety. It is preferably oleophilic and/or hydrophobic when in isolation.
Said second component may include a functional group or functional group precursor capable of undergoing a condensation reaction with a functional group, especially a hydroxy group, of said first component. Said functional group or precursor preferably includes a moiety —O—; it may be an hydroxy or an optionally-substituted alkoxy group. When it is an alkoxy group, the group may suitably represent a functional group precursor which may undergo an initial transformation prior to said condensation reaction.
Said second component preferably includes a hydrophilic and/or oleophobic moiety.
Said second component may comprise an optionally-substituted siloxane or, preferably, is of general formula
wherein M represents a silicon or a titanium atom and each of R
1
, R
2
, R
3
and R
4
is independently selected from hydrogen or halogen atoms; a hydroxy group; an optionally-substituted alkyl, alkenyl or alkynyl group; an optionally-substituted alkoxy group; or an optionally-substituted saturated or unsaturated cyclic or heterocyclic group.
Unless otherwise stated in this specification, an alkyl, alkenyl or alkynyl group may have up to 20, suitably up to 10, preferably up to 8, more preferably up to 6, especially up to 4 carbon atoms with methyl, ethyl, propyl and vinyl groups being preferred; an alkoxy group may have up to 10, suitably up to 8, preferably up to 6, more preferably up to 4 carbon atoms; a saturated or unsaturated cyclic group may have up to 12, suitably up to 10, preferably up to 8, more preferably up to 6, carbon atoms and includes an aromatic group. A heterocyclic group may have 5 or 6 ring atoms.
Unless otherwise stated, where any group is stated to be “optionally-substituted” in this specification, it may be substituted by one or more: halogen atoms, especially fluorine, chlorine or bromine atoms; hydroxy or cyano groups; carboxyl groups or carboxy derivatives, for example carboxylic acid salts; and optionally-substituted alkyl, alkenyl, alkynyl, alkoxy, amino, sulphinyl, sulphonyl, sulphonate and carbonyl groups.
At least two, preferably at least three, of R
1
, R
2
, R
3
and R
4
includes a moiety —O— bonded to atom M.
Preferably, R
1
represents a hydroxy group or an optionally-substituted, especially an unsubstituted, alkoxy group.
R
2
may represent a hydroxy group or an optionally-substituted alkoxy, alkyl, alkenyl, cycloalkyl or phenyl group. Preferably, R
2
represents a hydroxy group or an optionally-substituted, especially an unsubstituted, alkoxy group.
R
3
may represent a hydroxy group or an optionally-substituted alkoxy, alkyl, alkenyl, cycloalkyl or phenyl group. R
3
preferably represents a hydroxy group or an optionally-substituted alkoxy group. A preferred optionally-substituted alkoxy group may include a saturated or unsaturated carbon chain and may be substituted by a group —COOQ, where Q represents an optionally-substituted, especially an unsubstituted, alkyl group or a cationic group, especially a group NH
4
+
.
R
4
may represent a group which confers hydrophilicity and/or oleophobicity on said second component. R
4
may represent an optionally-substituted alkoxy, alkyl, alkenyl, cycloalkyl or phenyl group. A preferred optionally-substituted alkoxy group may be as described above for group R
3
. A preferred optionally-substituted alkyl group is substituted by a group —S(O)
x
(OH)
y
where x and y independently represent 0, 1, 2 or 3 provided that x+y=3. Preferably, y represents 1. R
4
preferably represents an optionally-substituted alkoxy or alkyl group.
Where M represents a titanium atom, R
1
and R
2
preferably represent hydroxy groups and R
3
and R
4
preferably represent alkoxy groups substituted by a group —COOQ as described above.
Where M represents a silicon atom, R
1
, R
2
and R
3
may be the same or different, preferably the same, and may represent a hydroxy group or an optionally-substituted, especially an unsubstituted, alkyl group. R
4
preferably represents an optionally-substituted alkyl group. In one class of compounds, R
4
may represent an alkyl group substituted by a group —S(O)
x
(OH)
y
as described above. In another class of compounds, R
4
may represent an alkyl group substituted by a group Rf —(Y)
m
—(X)
n
— wherein X represents —NR
5
— wherein R
5
represents a hydrogen atom or an optionally-subs

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