Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-04-19
2001-10-23
Jagannathan, Vasu (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C523S160000, C106S410000, C106S411000, C106S412000, C106S413000, C540S141000
Reexamination Certificate
active
06306938
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for the production of copper phthalocyanine pigment compositions which are useful in the coloration of surface coatings, especially oil ink formulations used in printing.
The production of copper phthalocyanine pigments via milling of crude copper phthalocyanine in the presence of grinding auxiliaries such as organic/inorganic salts followed by either a separate solvent treatment with partially water miscible solvents, as detailed in British Patent number GB 140836, or, a separate aqueous emulsion treatment of the milled mass with liquid amines in the presence of surfactants such as an alkali metal salt of wood rosin, as detailed in U.S. Pat. No. U.S. Pat. No. 5,449,774, are known. Where the solvent treatment step involves the use of polar aliphatic solvents, as disclosed in GB 1140836, the initial dry (substantially liquid free) milling step requires a high proportion of the grinding auxiliary such as organic/inorganic salts, typically 2 parts grinding auxiliary to 1 part of crude copper phthalocyanine.
Surprisingly we have now found that the milling of crude copper phthalocyanine in combination with natural or chemically-modified resins followed by a separate solvent conditioning or aqueous emulsion conditioning treatment leads to copper phthalocyanine compositions which exhibit superior pigmentary properties versus pigment compositions produced according to the method of GB1140836 or U.S. Pat. No. 5,449,774. In particular, the copper phthalocyanine compositions of the present invention demonstrate improved colour strength; gloss; and dispersion properties, especially when formulated into oil ink formulations. Furthermore, the process according to the present invention allows for a significant reduction, versus the process of GB1140836, in the amount of traditional grinding auxiliary material, such as organic/inorganic salts, when the subsequent conditioning step involves solvent. The use of the process of the present invention provides a more efficient and effective throughput of pigmentary material versus the process disclosed in GB 1140836.
SUMMARY OF THE INVENTION
Accordingly, the present invention provides a process for the production of pigmentary copper phthalocyanine in the beta crystalline phase comprising:
a) dry or aqueous milling of crude copper phthalocyanine in combination with a natural or chemically modified resin and, optionally, a grinding auxiliary followed by;
b) isolation of the milled mass followed by;
c) conditioning treatment of the milled mass.
DESCRIPTION
As an essential step in the process according to the present invention the crude copper phthalocyanine is co-milled with a natural or chemically modified resin and optionally a grinding auxiliary. Crude in respect of copper phthalocyanine, as defined herein, means of non-pigmentary size, typically more than about 10 microns.
The crude copper phthalocyanine is prepared by any of the well established processes such as reaction at elevated temperature of phthalic anhydride with urea and a copper salt in the presence of a catalytic amount of a transition metal compound such as ammonium molybdate, the reaction being carried out in a high boiling aromatic solvent such as nitrobenzene or in the absence of solvent in a “dry-bake” process. Standard processes for the production of crude copper phthalocyanine are detailed in “Phthalocyanine Compounds” by Moser and Thomas, Reinhold Publishing Corporation 1963 the disclosures of which are incorporated herein by reference.
Resins suitable for use in the process of the present invention include rosin, the principal component of which is abietic acid; chemically modified rosins such as hydrogenated, dehydrogenated or disproportionated rosin; dimerised or polymerised rosin; partially esterified rosin; non-esterified or partially esterified maleic- or phenolic-modified rosin and rosin or rosin derivatives polymerised with substances like formaldehyde and mixtures thereof. Preferred resins for use herein include such commercially available materials as Staybelite® resin (hydrogenated rosin) available from Hercules (United States), Recoldis A resin® (disproportionated rosin) as distributed in Britain by Langley Smith (Britain), and Dymerex® resin (dimerised rosin) available from Hercules (United States). In the milling stage, the natural or chemically-modified resin is generally present in an amount of from about 1% to about 15%, preferably from about 2% to about 5% by weight, based on the weight of crude copper phthalocyanine charged to the milling apparatus. The preferred resins in the present invention are hydrogenated rosin and disproportionated rosin.
A grinding auxiliary, as defined herein, means any material used to aid the reduction in size of copper phthalocyanine from crude to pigmentary using attrition/grinding technology. Grinding auxiliary materials suitable for use in the process of the present invention include, calcium chloride, sodium chloride, sodium sulphate, sodium formate, sodium acetate or other organic or inorganic salt, phthalimide or phthalic anhydride and mixtures thereof The preferred grinding auxiliaries in the present invention are sodium formate, sodium chloride and sodium acetate. Where the milling is effected by a dry milling technique, the grinding auxiliary is present in an amount of from about 2% to about 15 %, preferably from about 6% to about 8 % by weight, based on the weight of crude copper phthalocyanine charged to the milling apparatus.
Milling, as defined herein, means a process by which the solids are subjected to attrition, grinding etc. to achieve particle size reduction. Dry milling, as defined herein, means a process by which the solids are subjected to attrition, grinding etc. to achieve particle size reduction while substantially free of liquid. However as detailed later herein, a low level of solvent (or amine) may be added during the milling stage. Milling of the crude copper phthalocyanine and resin mixture of the present invention may be effected by either a dry or aqueous technique. If the milling is effected by a dry technique, suitable apparatus may be a ball mill or a vibration mill. If the milling is performed in an aqueous medium, the apparatus used is conveniently a bead mill. Where the milling is effected in an aqueous medium, there is no requirement for a grinding auxiliary.
As a second essential step in the process according to the present invention the milled mixture (of crude copper phthalocyanine, resin and optionally grinding auxiliary) is isolated. Where the milling step was essentially a dry process the milled mass may be isolated by direct discharge from the milling apparatus. Where milling was effected by an aqueous milling technique, the milled mass is isolated in powder form. However, if the conditioning of the milled mass is to be effected by emulsion treatment, then the milled mass which has been generated by an aqueous milling technique may optionally be isolated and used in the subsequent emulsion conditioning step in the form of a “filter cake”.
As a further essential step in the process of the present invention the isolated milled mixture of crude copper phthalocyanine, resin, and optionally, grinding auxiliary is conditioned either by treatment with a solvent, an emulsion or with a carboxylic acid.
Where conditioning is effected via treatment with a solvent the milled mass is dispersed into the solvent by addition, either portion-wise or a single addition, and agitation until fully “wetted out” so that all the dry mass is in contact with solvent. An aqueous solution of the resin may be added at this stage at a level of from 0 to about 10%, preferably from about 1% to about 5% by weight of the crude copper phthalocyanine. The resultant slurry is then heated to temperatures ranging from about 50° C. to the boiling point of the solvent. The solvent treatment is performed for sufficient time to allow conversion of the pigmentary copper phthalocyanine to substantially the beta crystalline modification. Such phase change can be routinel
Dykes Kenneth Grant
Healy Thomas
Keirs David
Mathers Richard Ernest
Ciba Specialty Chemicals Corp.
Crichton David R.
Jagannathan Vasu
Shosho Callie E.
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