Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Patent
1993-11-15
1995-01-10
Bell, Mark L.
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
106493, C09B 4501, C09B 4100
Patent
active
053803639
DESCRIPTION:
BRIEF SUMMARY
This specification describes an invention relating to a process for the manufacture of azo metal salt pigments, also known as lake or toner pigments, by incorporating polymeric dispersing agents during the manufacturing process.
Processes for the manufacturing of azo metal salt pigments such as CI Pigment Red 48 (also known as 2B Toner or Permanent Red 2B), CI Pigment Red 53 (also known as Red Lake C or Lake Red C) and CI Pigment Red 57 (also known as 4B Toner, Lithol Rubine, Rubine Toner or Permanent Red 4B) are well known. There are three main stages: and
Preparation of the azo compound involves diazotisation of an amine, such as a toluidene derivative, and coupling of the diazotised amine onto a naphthol derivative, such as 2-naphthol or 2-hydroxy-3-naphthoic acid.
Resination is generally achieved by the addition of an aqueous solution of a high acid value resin, such as a rosin. Rosins are mainly mixtures of C.sub.20 fused-ring monocarboxylic acids typified by levopimaric and abietic acids. A more detailed description of rosins and other natural resins is given in "Encyclopaedia of Chemical Technology", Third Edn., ed. Kirk-Othmer, vol. 20, pp. 197-206. The point at which the resin is added during in the manufacturing process will depend on the properties required of the final pigment, see American Inkmaker, December 1986, pp. 30-33.
Laking is generally achieved by the addition of a water-soluble inorganic salt of the metal to the resinated pigment. It is also well known that heat treatments subsequent to the laking stage can influence transparency, strength and intensity of the final pigment.
British Patent No. 1,342,746 discloses the use of a compound of the formula: dispersing lake or toner pigments in organic liquids. The polyester is derived either from a hydroxycarboxylic acid of the formula: least 8 carbon atoms in which there are at least 4 carbon atoms between the hydroxy and carboxylic acid groups, or, from a mixture of a hydroxycarboxylic acid of the formula (2) and a carboxylic acid which is free from hydroxy groups.
British Patent 1,373,660 discloses the use of a compound of the formula: through which it is attached to the carbonyl group, acid or a quaternary ammonium salt group, and of the formula (1): as a dispersant for dispersing lake or toner pigments in organic liquids. The patents also disclose the use of these dispersions in the production of gravure printing inks.
As the dispersants of the formulae (1) and (3) are widely used in the dispersion of azo metal salt pigments, it would be desirable to incorporate them in the pigment. However, they are insoluble in water and cannot, therefore, be easily incorporated into the aqueous based processes used in the manufacture of azo metal salt pigments. It has now been found that these dispersants are sufficiently compatible with a basic aqueous solution of an acid resin to allow the preparation of a clear or translucent solution of the dispersants in the resin solution, which can be readily incorporated into the pigment at the resination stage, in place of the simple aqueous solution of the resin alone, to give an azo metal salt pigment which exhibits superior brightness, strength, gloss and/or flow in organic media, such as paints and inks.
In the process of the present invention, the azo metal salt pigment is obtained by laking, with a metal, a monoazo pigment formed from toluidine derivative such as 1-amino-5-methylbenzene-2-sulfonic acid (p-toluidine-m-sulfonic acid), 1-amino-4-methyl-5-chlorobenzene-2-sulfonic acid or 1-amino-4-chloro-5-methylbenzene-2-sulfonic acid as a diazo component and 2-naphthol or 2-hydroxy-3-naphthoic acid as a coupling component. The metal used for the above laking includes Ca, Ba, Sr, Mn, Zn, Al, Mg and Fe.
The dispersant of the formula (1) used in the present invention will be detailed hereinafter.
The salts of the polyesters can be either salts of the polyesters with metal atoms or salts with bases such as ammonia or organic derivatives thereof. The metal salts can conveniently be obtained, for example, by
REFERENCES:
patent: 3778287 (1973-12-01), Stansfield et al.
patent: 3996059 (1976-12-01), Stansfield et al.
patent: 4334932 (1982-06-01), Roueche
Coispeau Gerard
Schofield John D.
Bell Mark L.
Francolor Pigments SA
Hertzog Scott L.
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