Radiation imagery chemistry: process – composition – or product th – Diazo reproduction – process – composition – or product – Composition or product which contains radiation sensitive...
Reexamination Certificate
2001-03-08
2002-10-01
Chu, John S. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Diazo reproduction, process, composition, or product
Composition or product which contains radiation sensitive...
C430S175000, C430S176000, C525S061000
Reexamination Certificate
active
06458503
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of the Invention
This invention is directed to a fluorinated aromatic acetal polymer composition, a method of preparing such a composition, a photosensitive composition which comprises such a polymer composition and a diazo resin, and imageable members such as lithographic printing plate precursors comprising such a photosensitive composition. After imaging, such a precursor is useful as a lithographic printing plate.
2. Background Information
The use of acetal polymers in photosensitive compositions is well known to those skilled in the art, as disclosed for example in: U.S. Pat. Nos. 5,169,897; 5,219,699; 5,262,270; and 5,534,381. However, although photosensitive compositions containing such acetal polymers have generally performed in an effective manner, improvement in terms of enhanced press life of printing plates containing such compositions is desirable. In addition, enhanced water repellency (to retain high image quality by maximizing hydrophobicity with respect to the hydrophilic portions of the composition) and resistance to plate cleaner solutions (to permit plate cleaning without concurrent reduction in image quality) are desirable.
It is also well known to those skilled in the art that photosensitive compositions comprising a diazonium compound and a polymeric binder may be prepared and used in imageable members such as lithographic printing plates. For example, U.S. Pat. No.3,790,382 discloses an oleophilic composition suitable for use as the ink-receptive layer of a printing plate, in which the oleophilic composition comprises a light-sensitive diazo resin, a polyamide resin binder, and a polymer containing a non-aromatic fluorinated component. However, in contrast to the photosensitive composition of the present invention, the oleophilic composition disclosed in U.S. Pat. No. 3,790,382 contains a fluoropolymer component which must be non-aromatic.
It has now been found that photosensitive compositions comprising the novel fluorinated aromatic acetal polymers of this invention and at least one diazo resin advantageously provide enhanced press life, water repellency and resistance to plate cleaner solutions when such photosensitive compositions are employed as part of an imageable element such as a lithographic printing plate. Accordingly, it is an object of this invention to provide this novel fluorinated aromatic acetal polymer. It is another object of this invention to provide a method of preparing such a fluorinated aromatic acetal polymer. It is yet another object of this invention to provide a photosensitive composition comprising at least one diazo resin and at least one such fluorinated aromatic acetal polymer of this invention. It is yet another object of this invention to provide a method of preparing such a photosensitive composition. It is yet another object of this invention to provide an imageable member comprising a support and a photosensitive composition of this invention.
SUMMARY OF THE INVENTION
The fluorinated aromatic acetal polymer composition of this invention comprises at least one unit of A and at least one unit of either B or C, or at least one unit of each of A, B and C, and optionally further comprises at least one unit of either D or E, or at least one unit of each of D and E, wherein the units are linked together by single covalent C—C bonds and have the formulae:
where A, B, C, D and E are present in the corresponding ratio n
1
l:n
2
: n
3:n
4
:n
5
, where n
1
=10-80 mole %; n
2
=0-65 mole %; n
3
=0-65 mole %; n
4
=0-50 mole %; n
5
=0-20 mole %; R
A
is H or a C
1
-C
11
alkyl group, or an aryl group that does not contain fluorine, and R
B
and R
C
are aryl groups that contain fluorine, including (trifluoromethyl) phenyl and fluorophenyl groups. Here an aryl group is defined as any group obtained from an aromatic compound by removing one of the hydrogen atoms attached to an aromatic carbon atom.
In one preferred embodiment, the unit B has the formula:
where each of R
1
and R
2
is independently F, H, or an alkyl group. The fluorinated aromatic acetal polymer composition is preferably prepared by the process comprising reacting a hydrolyzed polyvinyl acetate polymer or copolymer with at least one non-fluorinated aldehyde component, and at least one fluorinated aromatic component.
The photosensitive composition of this invention comprises at least one diazo resin, and at least one fluorinated aromatic acetal polymer composition as described above. The imageable member of this invention comprises a support and the photosensitive composition as described above applied to the support. In a particularly preferred embodiment, the imageable member of this invention is used as a lithographic printing plate precursor, and upon imaging is used as a lithographic printing plate.
DETAILED DESCRIPTION OF THE INVENTION
The fluorinated aromatic acetal polymer composition of this invention comprises at least one unit of A and at least one unit of either B or C or at least one unit of each of A, B and C, and may further comprise at least one unit of either D or E, or at least one unit of each of D and E, wherein the units are linked together by single covalent C—C bonds and have the formulae:
where A, B, C, D and E are present in the corresponding ratio n
1
:n
2
:n
3
:n
4
: n
5
, where n
1
=10-80 mole %, n
2
=0-65 mole %, n
3
=0-65 mole %, n
4
=0-50 mole % n
5
=0-20 mole %, R
A
is H or a C
1
-C
11
alkyl group, or an aryl group that does not contain fluorine, and R
B
and R
C
are aryl groups that contain fluorine, including (trifluoromethyl) phenyl and p-fluorophenyl groups. The non-fluorinated alkyl and aryl groups may be substituted or unsubstituted. Aralkyl groups are particularly preferred.
In a preferred embodiment, and unit B has the formula:
where each of R
1
and R
2
is independently F, H or an alkyl group. In a particularly preferred embodiment, R
1
and R
2
are each F.
In a preferred embodiment, the composition of the invention further comprises at least one acid group having a pKa equal to or less than 11. The acid group is preferably a carboxylic acid group and most preferably is derived from a carboxybenzaldehyde. The composition preferably further comprises at least one photopolymerizable ethylenically unsaturated group, at least one photocrosslinkable group, or a combination thereof.
The fluorinated aromatic acetal polymer composition of this invention is preferably prepared by the process comprising reacting a hydrolyzed polyvinyl acetate polymer or copolymer with at least one non-fluorinated aldehyde component and at least one fluorinated aromatic component. The term aldehyde component includes aldehyde derivatives such as acetals. The reaction conditions which may be used are those that will be well known and understood by those skilled in the art for reacting such components. For example, the components may be reacted at temperatures in the range of from ambient to about 150° C., preferably from about 40° C. to about 100° C., for a period of time ranging from about 30 minutes to about 24 hours, preferably about 2 hours to about 8 hours. Relative to the hydrolyzed polyvinyl acetate polymer or copolymer, the non-fluorinated aldehyde components may be reacted in amounts from about 10 to about 80 mole %; the fluorinated components may be reacted in amounts of from about 5 to about 65 mole %.
In a preferred embodiment, the hydrolyzed polyvinyl acetate polymer or copolymer is prepared as follows. Vinyl acetate is polymerized, or copolymerized with other monomers, to produce a polyvinyl acetate polymer or copolymer. The weight average molecular weight (M
w
) of the polyvinyl acetate polymer or copolymer is about 20,000 to about 130,000 g/mole, preferably about 35,000 to about 130,000 g/mole. Vinyl alcohol groups are then produced by hydrolysis of the acetate groups. Acetate groups are hydrolyzed to the extent of about 70-98 mole %, preferably about 80-98 mole %. Other monomers useful in making a copolymer include vinyl esters o
Alden Melinda
Perron Paul
Platzer Stephan
Baker & Botts L.L.P.
Chu John S.
Kodak Polychrome Graphics LLC
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