Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Patent
1996-02-05
1998-05-19
Bell, Mark L.
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
106410, 106411, 106413, 106 3176, 106 3177, 106 3178, C09B 6750
Patent
active
057530220
DESCRIPTION:
BRIEF SUMMARY
This application claims benefit of international application PCT/GB94/02786, filed Dec. 20, 1994.
The present invention related to a process for making a non-aqueous dispersion (NAD) of a copper phthalocyanine (CuPc) which is especially suitable for direct incorporation into a printing ink.
In order to disperse pigments uniformly in a non-aqueous medium especially designed dispersing agents are required to produce dispersions having acceptable viscosity and stability properties, which when incorporated into printing inks give inks with acceptable flow characteristics. Thus, GB 1,373,660 discloses polyesteramine dispersants obtainable by reacting poly(hydroxycarboxylic acids) (hereinafter PHCA) with diamines, especially alkylenediamines, and salts thereof. GB 2,001,083 discloses polyesteramine dispersants obtainable by reacting PHCA with poly(C.sub.2-4 -alkyleneimine) (hereafter PAI) and salts thereof. U.S. Pat. No. 5,000,792 discloses polyesteramine dispersants obtainable by reacting 2 parts of PHCA with 1 part of a di-alkylenetriamine. NAD containing high concentrations of pigment often exhibit high viscosity and are difficult to handle and formulate into inks and paints. It has therefore been proposed to incorporate fluidising agents into such NAD's as disclosed in GB 1,508,576 (U.S. Pat. No. 4,057,436).
Offset inks and varnishes are presently made by first converting crude CuPc to pigmentary CuPc by salt milling in the presence of a water-miscible solvent such as ethylene glycol followed by washing with water to form a press paste which is either (1) dried and dispersed in an aliphatic medium or oil and formulated into an ink or (2) flushed into the aliphatic medium to make a "flush" colour which is then incorporated into the aliphatic medium to form the printing ink or varnish. The direct dispersion of crude CuPc into the aliphatic medium is difficult to achieve and the salt grinding process is expensive and produces an effluent which poses an environmental hazard. There is a clear advantage of avoiding salt milling by milling the crude CuPc in the solvent medium itself.
It has recently been proposed, in U.S. Pat. No. 5,175,282, to mill crude CuPc in 1 to 10% of an organic solvent at elevated temperature and then heat the milled paste in an aqueous medium in order to obtain pigmentary CuPc which when formulated in compositions such as surface coatings and printing inks exhibits improved flow characteristics compared with compositions containing dry-ground CuPc pigments.
It has now been found that brighter and greener shades of CuPc in inks and varnishes are obtainable in NAD if the crude CuPc is milled with dispersing agents in a non-aqueous solvent itself at a temperature above 50.degree. C.
Thus, according to the invention there is provided a method of preparing a NAD of CuPc which comprises milling crude CuPc in a high boiling liquid at a temperature from 50.degree. to 150.degree. C. in the presence of an amine with a PHCA of formula (1)
The precise structure of the chain terminating group Y is not critical provided it is inert to the other components of the composition under the normal processing conditions to which it is subjected. It is preferably free from ionic and strongly polar groups and preferably has a molecular weight of less than 300 and contains only C and H or C, H and O atoms.
The optionally substituted hydrocarbyl group Y is preferably alkyl or alkenyl containing up to 35 carbon atoms, especially from 7 to 25, and more especially from 7 to 20 carbon atoms such as heptyl, octyl, undecyl, lauryl, heptadecyl, heptadecenyl, heptadecadienyl, stearyl, oleyl, linoleyl or such a group substituted by a hydroxy, halo or alkoxy group, especially C.sub.1-4 alkoxy. Other values for Y include, C.sub.4-8 -cycloalkyl, such as cyclohexyl; polycycloalkyls, for example, polycyclic terpenyl groups which are derivable from naturally occurring acids such as abietic acid; aryl, such as phenyl; aralkyl, such as benzyl and polyaryl, such as naphthyl, biphenyl, stilbenyl and phenylmethylphenyl. Such groups ar
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Database WPI, Section Ch, Week 8824, Derwent Publications Ltd., Class E23, AN 88-124791 & DD.A.243 182. Feb. 25, 1987 see abstract.
Schofield John David
Thetford Dean
Bell Mark L.
Hertzog Scott L.
Zeneca Limited
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