Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-05-24
2004-02-24
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...
C523S160000, C524S057000, C524S062000, C524S160000, C524S306000, C524S310000, C524S312000, C524S315000, C524S317000, C524S320000, C524S321000
Reexamination Certificate
active
06696508
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to a polymer dispersion with improved biodegradability.
2. Description of the Related Art
In printing shops, automatic ink stations which can prepare printing pastes in a fully automatic process are increasingly employed. The presence of liquid metering components, such as liquid dye and thickener formulations, is advantageous for automatic dosage. A printing paste essentially consists of water, a thickener and a dye, as well as other auxiliary agents in accordance with the printing method employed.
Textile printing methods can be divided into pigment printing, dye printing, carpet printing, carpet spray printing and others. The classes of dyes employed include, for example, pigments, reactive dyes, disperse dyes, acid dyes, basic dyes, metal complex dyes and/or vat dyes. The printing plants employed include, for example, rotary machine printing, flat printing, roller printing, spray printing, ink jet printing, space printing, Vigoureux (melange) printing and others.
In addition to woven and knitted fabrics, worsted yarns, engineering fabrics, fleeces, sheets, papers etc., carpets are also printed. In this case, rotary machine printing and carpet spray printing are mainly employed. In carpet spray printing, two types of plants are prevalent which use different methods of working and are designated by the two suppliers as Chromojet® (Zimmer) and Millitron® (Milliken). Today, the Chromojet® plant is predominantly operated with synthetic printing thickeners. The principle is that a printing paste is supplied under pressure to a magnetically controlled nozzle whose timing is controlled by a computer in accordance with the pattern to be printed. In the Millitron® plant, a permanent jet of printing paste is deflected onto the substrate or back into the storage vessel in accordance with the printing image. Both Chromojet® and Millitron® are equipped with a large number of nozzles.
All printing methods require a particular viscosity and rheology in order to obtain a printing performance which is the best in each case. Thus, the thickeners (printing gums) are of central importance in every printing paste formulation.
In principle, for the mentioned printing methods, dyes and substrates, native or synthetic thickeners can be used.
Known synthetic printing thickeners mostly comprise polyacrylates or copolymers of acrylic acid with other ethylenically unsaturated compounds which may additionally be cross-linked. The pure polyacrylic acid derivatives are in the form of powders and thus only conditionally suitable for automatic metering devices. Further, for polyacrylic acid in the form of powder, a maximum allowable concentration was established in the newly introduced category 4 (non-genotoxic carcinogens which allow for threshold values to be established). Thus, in the future, restrictions to the handling of polyacrylic acid in the form of powder are possible.
Today, in addition to the use of powdery thickeners for manual dosage, the state of the art is to use paste-like synthetic thickeners which may be obtained either by emulsion polymerization of acrylic acid or its derivatives or by dispersing the powdery polyacrylic acid or its derivatives in a suitable dispersant. Paste-like thickeners which are currently on the market are predominantly based on mineral oils as water-in-oil emulsions with a high solids content, and their use results in the pollution of waste water with poorly biodegradable or non-biodegradable hydrocarbons. The mineral oils are deposited in the sewage sludge of water treatment plants and degraded by microorganisms only in very low amounts.
A precondition for the use of paste-like formulations of powdery polyacrylic acid derivatives is the preparation of a stable dispersion. A number of factors are responsible for the stability of such dispersions, for example, viscosity, rheology, density of the carrier medium, pH value, filler content, use of dispersing aids and the like. As to viscosity, carrier media having too low a viscosity are less suitable because stable dispersions can hardly be obtained therewith. But too high a viscosity is also disadvantageous because in this case, the paste-like polyacrylic acid derivatives can no longer be processed in automated ink formulation plants.
To obtain polyacrylates having a good thickening effect, the polyacrylic acid must be neutralized. The prior art especially comprises ammonium, sodium, potassium salts and quaternary amines.
The water-in-oil emulsions currently on the market must be inverted when incorporated in water; only then, the polymer can swell and become active in its function as a printing thickener. With self-swelling paste-like thickener systems, this reversal of the emulsion can proceed by itself upon incorporation into water, but with non-self-swelling systems, a surface-active compound must be added, or high shear forces must be applied.
In EP 0 208 217 A, environment-friendly flocculant organosols based on dicarboxylic acid esters are described. In industrial-scale syntheses, they are prepared with economic efficiency and constant quality. Consequently, the biological degradation proceeds from the oxygen-containing sites of the molecule, perhaps after a preliminary hydrolytic cleavage of the ester group, for example, catalyzed by enzymes, and both the carbon chains of the dicarboxylic acid and those of the alcohol are microbially degraded by &bgr;-oxidation to the highest possible extent.
DE 33 02 069 A describes preparations in which the oil phase may consist of a mixture of aliphatic or aromatic hydrocarbons with natural vegetable or animal triglycerides, and of fatty acid monoesters, preferably C-
1-4
alkyl esters of C
12-24
fatty acids.
EP 0 045 720 A and EP 0 080 976 A describe water-in-oil emulsion polymerizates for use in cosmetic agents which require hydrophobic organic liquids, such as aliphatic or aromatic hydrocarbons, oils of animal or vegetable origin, and the corresponding denaturing oils as the oil phase for the polymerization.
The present invention is concerned with the problem of the pollution of waste water with hydrocarbons by the paste-like formulation of printing thickeners. At the same time, easier-to-handle paste-like formulations of polymers were to be developed.
SUMMARY OF THE INVENTION
In a first embodiment, the invention relates to a polymer dispersion containing one or more polymers in a synthetic carrier medium which is completely or partially biodegradable. For a constant product quality, it is advantageous to use biodegradable synthetic carrier media.
In particular, the invention relates to a polymer dispersion containing one or more polymers and a synthetic carrier medium based on a biodegradable component, or a mixture of biodegradable components, or a mixture of one or more biodegradable components with one or more less readily biodegradable components.
The term “polymer dispersion” within the meaning of the present invention also comprises emulsions of polymers.
Natural vegetable oils or their derivatives often consist of a mixture of different fatty acids. They contain residues of different chain lengths and different degrees of saturation, depending on the respective vegetable base. In some cases, a smaller amount of polymer can be incorporated in a vegetable oil than can be incorporated in formulations based on mineral oil or synthetic carrier media. Therefore, according to the present invention, these are less suitable as a carrier medium for the polymer dispersion.
As compared to vegetable oils, synthetic carrier media have the advantage that they can be produced in a constant quality. As a rule, they contain one or more defined compounds or, for multiple esters, they contain the acid in different stages of esterification. Further, it was found that a higher active content of polymer dispersions is achieved in many cases in synthetic carrier media. This means that a higher amount of powdery polyacrylic acid can be dispersed in a synthetic carrier medium before its viscosity becomes to
Fischer Thomas
Willmer Kurt
CHT R Beitlich GmbH
Sanders Kriellion A.
Venable LLP
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