Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Reexamination Certificate
1998-02-26
2001-01-23
Lovering, Richard D. (Department: 1712)
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
C252S363500, C516S077000, C516S105000
Reexamination Certificate
active
06176917
ABSTRACT:
TECHNICAL FIELD
The technical field of the present invention is that of the solubilization of boron-containing compounds, especially, but without implying a limitation, for the purpose of adding boron-containing compositions to starch pastes.
More precisely, the invention relates to the incorporation of boric acid and/or borates, such as borax, into aqueous compositions, for example the starch compositions of the type employed for the manufacture of starch pastes. The latter are useful especially in the paper/cardboard industry and more particularly for the manufacture of cardboard and cardboard packagings.
Even more precisely, the invention relates to a boron-containing aqueous solution and to its use e.g. for addition to starch pastes, said solution being of the type containing at least one amino compound, preferably an aminohydroxylated compound or an alkylamine, and/or one polyhydroxylated compound.
PRIOR ART
Boron-containing or boracic products are derivatives of the chemical element boron (B) and reference will be made to this meaning in the present disclosure. Thus, in terms of the present invention, these derivatives are especially boric acid and borates, for example borax pentahydrate, borax decahydrate, sodium pentaborate tetrahydrate, sodium metaborate octahydrate, potassium tetraborate tetrahydrate and potassium pentaborate octahydrate. These commercial boron-containing products are widely used as more or less active ingredients in all kinds of compositions such as fertilizers, detergents, metallurgical cutting oils, drugs, cosmetics or starch-based products like paper/cardboard adhesives.
If starch pastes are taken as an example, it is necessary to know that they contain native starch and/or modified starch such as crosslinked starches. To be able to develop their power as a vehicle, said starches have to be heated in the presence of sodium hydroxide so as to cause all the starch grains to burst. This forms a paste to which the secondary starch is added. The latter defines the adhesive power of the paste since the combination of the temperature generated by the fluted rollers and the application of the paste to the cardboard makes it possible to form a complex bonded by the fact that the secondary starch has burst. One of the difficulties encountered by the applicators during the formation of the paste concerns viscosity control. The viscosity must be carefully fixed so as to allow easy coating onto the substrates to be glued. Thus it is known to use boron-containing adjuvants for this purpose, said adjuvants having plasticizing, reinforcing, thickening and adhesion promoting effects (inter alia) on starch paste.
Conventionally the boron-containing product added consists of borax powder, which is incorporated continuously or semicontinuously into the starch paste during its formation. This pulverulent boron-containing form is the cause of several disadvantages. Firstly, borax powder presents storage problems because it tends to absorb water, resulting in caking phenomena. Now, it is clear that a caked product is difficult to handle, especially because it does not flow. Secondly, borax powder (whether caked or not) is liable to cause dosage inaccuracies because of the blocking or jamming incidents which can occur in the powder feed systems (hopper, feed screw) conventionally employed in continuous paste manufacturing processes. Thirdly, borax powder mixes poorly with the starch paste during its formation; this necessitates sophisticated stirring means and longer reaction or incorporation times.
In an attempt to surmount these difficulties, it has been proposed to add the boric acid or the hydrated borax in the form of a solution since obviously the handling of a liquid and the intimate mixing of a liquid with a liquid are simpler than the handling of a solid.
Thus European patent application No. 326 247 describes a process for the addition of boric acid or borate to a starch paste during its preparation. The boron-containing liquid composition used in the invention according to said patent application of the prior art comprises 25 to 35% by weight of boric acid or borate, 55 to 35% by weight of water and 20 to 30% by weight of monoethanolamine or a polyhydroxylated organic compound. Such compositions are relatively poor in boron-containing active principle. Consequently the corresponding theoretical concentrations of boron trioxide, B
2
O
3
, are even lower. These are not optimal conditions for the efficacy of the boron-containing product as a starch paste adjuvant. Moreover, it demonstrates a certain inability of the invention according to said patent application EP no. 326 247 to improve the solubility of boron-containing products in water, said solubility being known to be very low. Furthermore, in this process of the prior art, care is taken to prepare the boron-containing liquid composition at dissolution temperatures below 70° C. The intention here is to avoid the formation of a soluble complex between the boron-containing product and the ingredients of the monoethanolamine type or polyhydroxylic compound type. This technical provision conceals the fear of an organic perturbation or even a lowering of the efficacy of the boron-containing product in the event that it should form a complex. Finally, this known boron-containing liquid composition has poor performance characteristics and consequently a low economic viability.
American U.S. Pat. No. 4,332,609 describes a boron-containing fertilizer comprising a compound of boric acid with an alkanolamine. Said document has no bearing inter alia on the use of boron-containing liquid as a starch paste adjuvant.
It therefore has to be concluded that the prior art is imperfect, or even has failed, as regards the provision of a liquid boron-containing substitute for traditional borax powder, especially in the context of addition to various compositions, for example starch pastes, decontaminating compositions for radioactive products, biocidal compositions or brightening and waxing compositions, inter alia.
This being so, one of the essential objectives of the invention is to provide a boron-containing adjuvant, especially for starch paste, which is in the form of a stable liquid and which has a high efficacy per unit mass, especially when functioning as an adhesion promoter, plasticizer and cohesion strengthener for starch adhesive.
Another objective of the invention is to provide a boron-containing liquid adjuvant, especially for starch pastes, decontaminating compositions for radioactive products, biocidal compositions or brightening and waxing compositions, which is easy to prepare and handle.
Another essential objective of the invention is to provide a boron-containing liquid adjuvant, especially for starch pastes, decontaminating compositions for radioactive products, biocidal compositions or brightening and waxing compositions, which is economic by virtue of using a single product for several actions.
Another essential objective of the invention is to provide a substitute boron-containing liquid adjuvant, especially for starch pastes, decontaminating compositions for radioactive products, biocidal compositions or brightening and waxing compositions, said adjuvant being in the form of a solution.
Another essential objective of the invention is to provide a boron-containing liquid adjuvant, especially for starch pastes, decontaminating compositions for radioactive products, biocidal compositions or brightening and waxing compositions, which possesses at least one of the following properties: bactericidal, fungicidal and antifoaming (inter alia).
Another objective of the invention is to provide a simple and inexpensive process for the preparation of the above-mentioned adjuvant.
BRIEF DESCRIPTION OF THE INVENTION
These and other objectives are achieved by the present invention, which relates first and foremost to a boron-containing aqueous solution, especially for addition to starch paste, said solution containing at least one amino compound (alkylamino and/or aminohydroxylated and/or arylamino compound) and/or one
De Pannemacker Ren{acute over (e)}
Duclaud Didier Marcel
Lago Jean-Christophe
Bacon & Thomas
Development, Activities Chimiques Distribution
Lovering Richard D.
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