Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2000-08-17
2003-09-23
Sanders, Kriellion A. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C526S259000, C524S548000, C008S509000
Reexamination Certificate
active
06624219
ABSTRACT:
The present application relates to a set of novel (co)polymers, dispersion formulations, solid solutions and formulation conditions able to disperse a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in a stable nanoparticular form (nanodispersions) in an aqueous medium.
BACKGROUND OF THE INVENTION
Disperse dyes like a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye, in an aqueous medium are used, in various continuous and batchwise dyeing methods, in two basically different forms. The dyes are usually introduced into the dye bath in the form of a fine dispersion. The fineness of subdivision of the dyes is a critical factor in their use. Subdivision corresponding to a average particle size range of from 0.1 to 5.0 &mgr;m (100-5000 nm) is achieved by mechanically comminuting the dyes, obtained from their synthesis, by conventional methods, for example in stirred ball mills or kneeders in the presence of surfactants (dispersants). The function of the surfactants added is, on the one hand, to accelerate the mechanical comminution process and, on the other hand, to maintain the state of fine subdivision of the dyes in the dye bath, which state, when achieved, is thermodynamically unstable.
Mechanical comminution methods entail expensive apparatus and high expenditure of energy, and give low space-time yields. The lower limit of average particle size achievable by mechanical comminution methods is about 0.5 &mgr;m.
The use of the disperse dyes is fundamentally different in a process described in DE-OS 2,342,659. In that process the dyes are released from a previously dyed water-insoluble polymer material, which has a lower affinity than have the (textile) materials to be dyed, and which acts as a dye depot, into the dye liquor, from which the dyes then go onto the fibers to be dyed.
As a result of short-cycle dyeing processes, the fineness of subdivision and stability of dispersed dyes in dyeing liquors in recent years had to conform with evermore stringent requirements.
However, the dye dispersions of the type described are thermodynamically unstable and tend, under dyeing conditions, in particular under high temperature dyeing conditions, to recrystallize or agglomerate so as to form coarse particles. This interferes with the dyeing process, because the dye is filtered out, and hence gives unsatisfactory, uneven dyeings.
U.S. Pat. No. 4,286,959 relates to free-flowing formulations of disperse dyes, their preparation and their use for dyeing synthetic fibers. Said formulations comprise
(a) one or more disperse dyes, and
(b) one or more polymers which are soluble or colloidally soluble, both in water at a pH of from 1 to 9 and in an organic solvent, said polymers being prepared by free radical or ionic polymerization or by a poly-Menschutkin reaction,
(a) being enclosed in a matrix of (b) in the form of a solid solution in a state of molecular dispersion of extremely fine subdivision so that in an X-ray defraction pattern the dyes appear amorphous, said formulation having been prepared from a solution in said organic solvent which contains (a) and (b), with (a) being present in the solution in a state of molecular dispersion, by removing the solvent.
It is an object of the present invention to offer (co)polymers which perform better as dispersing agents for a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in an aqueous medium than the (co)polymers described in U.S. Pat. No. 4,286,959. It is another object of the present invention to offer novel dispersion formulations for a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in an aqueous medium with improved stability.
SUMMARY OF THE INVENTION
The present invention provides a set of novel (co)polymers, dispersion formulations and formulation conditions able to disperse a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in a stable nanoparticular form (nanodispersions) in an aqueous medium. Stable particles are defined as particles that do not crystallize, aggregate, flocculate, or precipitate out of the aqueous medium for a period of time depending on the application.
Novel (co)polymers which are employed in said dispersion formulations are random radical (co)polymers containing
20 to 50 mol % of styrene as component A,
15 to 35 mol % of acrylic acid as component B, and
15 to 60 mol % of dimethylaminoethylmethacrylate (DMAEM) or 4-vinyl pyridine as component C.
Said novel (co)polymers are usually obtained by free radical polymerization in a conventional manner.
In another embodiment of the present invention, high throughput or combinatorial techniques may be employed to discover or optimize the novel random radical (co)polymers by parallel design and/or synthetic and screening techniques.
The novel dispersion formulations contain
one of said novel (co)polymers,
a dye selected from the group consisting of a monoazo dye, a quinophthalone dye, an anthraquinone dye,
optionally further assistants useful for dyeing processes wherein said dispersion formulations are employed,
an aqueous system.
The average particle size reported in terms of hydrodynamic radius (r
H
) of the dispersed particles in said dispersion formulations is from 10-500 nm, preferably from 20-50 nm, more preferably from 20-30 nm. The average particle size may be characterized by light scattering measurements, especially Fiber Optic DLS measurements (FODLS), as described in detail later in the specification.
Said dispersion formulations are preferably obtained from solutions which comprise one of said novel (co)polymers, a dye selected from the group consisting of a monoazo dye, a quinophthalone dye, an anthraquinone dye, and optionally further assistants useful for dyeing processes wherein said dispersion formulations are employed. Said solutions are dried, preferably by spray drying, to obtain solid solutions. Said solid solutions are mixed with an aqueous system to obtain said dispersion formulations.
In another embodiment of the present invention, high throughput or combinatorial techniques may be employed to optimize or discover novel dispersion formulations for particular applications. Such techniques use parallel design and/or synthetic and screening techniques.
Solid solutions of said dispersion formulations, which are obtained after drying the solutions comprising one of said novel (co)polymers, a dye selected from the group consisting of a monoazo dye, a quinophthalone dye, an anthraquinone dye, and optionally further assistants useful for dyeing processes wherein said dispersion formulations are employed, are also claimed in the present invention.
Said novel dispersion formulations and solid solutions are especially useful for imprinting and dyeing paper and wall paper, for imprinting foils, transparences, paper for the reproduction of photographic pictures and graphics as well as for dyeing fibers for textiles, leather and furs and imprinting textiles, preferably by the release-paper process. Additionally, said novel dispersion formulations can be employed in inks, especially inks for ink-jets.
A further understanding of the nature and advantages of the invention herein may be realized by reference to the remaining portions of the specification.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a set of novel (co)polymers, novel dispersion formulations, novel solid solutions and formulation conditions able to disperse stable particles, nanodispersions, especially of a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in an aqueous medium.
While dispersion formulations of a dye selected from the group consisting of a monoazo dye, a quinophthalone dye and an anthraquinone dye in an aqueous medium have been made previously, this work has several novel and unique features. First, the formulations use (co)polymers of novel
Auweter Helmut
Carlson Eric
Han-Ting Chang
Heger Robert
Horn Dieter
BASF - Aktiengesellschaft
Keil & Weinkauf
Sanders Kriellion A.
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